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  • 1.
    Ah-King, Malin
    et al.
    Stockholm University, Faculty of Humanities, Department of Ethnology, History of Religions and Gender Studies. Uppsala University, Sweden; University of California, USA.
    Gowaty, Patricia Adair
    A conceptual review of mate choice: stochastic demography, within-sex phenotypic plasticity, and individual flexibility2016In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 6, no 14, p. 4607-4642Article, review/survey (Refereed)
    Abstract [en]

    Mate choice hypotheses usually focus on trait variation of chosen individuals. Recently, mate choice studies have increasingly attended to the environmental circumstances affecting variation in choosers' behavior and choosers' traits. We reviewed the literature on phenotypic plasticity in mate choice with the goal of exploring whether phenotypic plasticity can be interpreted as individual flexibility in the context of the switch point theorem, SPT (Gowaty and Hubbell ). We found >3000 studies; 198 were empirical studies of within-sex phenotypic plasticity, and sixteen showed no evidence of mate choice plasticity. Most studies reported changes from choosy to indiscriminate behavior of subjects. Investigators attributed changes to one or more causes including operational sex ratio, adult sex ratio, potential reproductive rate, predation risk, disease risk, chooser's mating experience, chooser's age, chooser's condition, or chooser's resources. The studies together indicate that choosiness of potential mates is environmentally and socially labile, that is, induced - not fixed - in the choosy sex with results consistent with choosers' intrinsic characteristics or their ecological circumstances mattering more to mate choice than the traits of potential mates. We show that plasticity-associated variables factor into the simpler SPT variables. We propose that it is time to complete the move from questions about within-sex plasticity in the choosy sex to between- and within-individual flexibility in reproductive decision-making of both sexes simultaneously. Currently, unanswered empirical questions are about the force of alternative constraints and opportunities as inducers of individual flexibility in reproductive decision-making, and the ecological, social, and developmental sources of similarities and differences between individuals. To make progress, we need studies (1) of simultaneous and symmetric attention to individual mate preferences and subsequent behavior in both sexes, (2) controlled for within-individual variation in choice behavior as demography changes, and which (3) report effects on fitness from movement of individual's switch points.

  • 2. Ardehed, Angelica
    et al.
    Johansson, Daniel
    Schagerström, Ellen
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Johannesson, Kerstin
    Pereyra, Ricardo T.
    Complex spatial clonal structure in the macroalgae Fucus radicans with both sexual and asexual recruitment2015In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 5, no 19, p. 4233-4245Article in journal (Refereed)
    Abstract [en]

    In dioecious species with both sexual and asexual reproduction, the spatial distribution of individual clones affects the potential for sexual reproduction and local adaptation. The seaweed Fucus radicans, endemic to the Baltic Sea, has separate sexes, but new attached thalli may also form asexually. We mapped the spatial distribution of clones (multilocus genotypes, MLGs) over macrogeographic (>500km) and microgeographic (<100m) scales in the Baltic Sea to assess the relationship between clonal spatial structure, sexual recruitment, and the potential for natural selection. Sexual recruitment was predominant in some areas, while in others asexual recruitment dominated. Where clones of both sexes were locally intermingled, sexual recruitment was nevertheless low. In some highly clonal populations, the sex ratio was strongly skewed due to dominance of one or a few clones of the same sex. The two largest clones (one female and one male) were distributed over 100-550km of coast and accompanied by small and local MLGs formed by somatic mutations and differing by 1-2 mutations from the large clones. Rare sexual events, occasional long-distance migration, and somatic mutations contribute new genotypic variation potentially available to natural selection. However, dominance of a few very large (and presumably old) clones over extensive spatial and temporal scales suggested that either these have superior traits or natural selection has only been marginally involved in the structuring of genotypes.

  • 3. Astor, Tina
    et al.
    Strengbom, Joachim
    Berg, Matty P.
    Lenoir, Lisette
    Marteinsdottir, Bryndis
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bengtsson, Jan
    Underdispersion and overdispersion of traits in terrestrial snail communities on islands2014In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 4, no 11, p. 2090-2102Article in journal (Refereed)
    Abstract [en]

    Understanding and disentangling different processes underlying the assembly and diversity of communities remains a key challenge in ecology. Species can assemble into communities either randomly or due to deterministic processes. Deterministic assembly leads to species being more similar (underdispersed) or more different (overdispersed) in certain traits than would be expected by chance. However, the relative importance of those processes is not well understood for many organisms, including terrestrial invertebrates. Based on knowledge of a broad range of species traits, we tested for the presence of trait underdispersion (indicating dispersal or environmental filtering) and trait overdispersion (indicating niche partitioning) and their relative importance in explaining land snail community composition on lake islands. The analysis of community assembly was performed using a functional diversity index (Rao's quadratic entropy) in combination with a null model approach. Regression analysis with the effect sizes of the assembly tests and environmental variables gave information on the strength of under- and overdispersion along environmental gradients. Additionally, we examined the link between community weighted mean trait values and environmental variables using a CWM-RDA. We found both trait underdispersion and trait overdispersion, but underdispersion (eight traits) was more frequently detected than overdispersion (two traits). Underdispersion was related to four environmental variables (tree cover, habitat diversity, productivity of ground vegetation, and location on an esker ridge). Our results show clear evidence for underdispersion in traits driven by environmental filtering, but no clear evidence for dispersal filtering. We did not find evidence for overdispersion of traits due to diet or body size, but overdispersion in shell shape may indicate niche differentiation between snail species driven by small-scale habitat heterogeneity. The use of species traits enabled us to identify key traits involved in snail community assembly and to detect the simultaneous occurrence of trait underdispersion and overdispersion.

  • 4.
    Audusseau, Helene
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology.
    Janz, Niklas
    Stockholm University, Faculty of Science, Department of Zoology.
    Implications of a temperature increase for host plant range: predictions for a butterfly2013In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 3, no 9, p. 3021-3029Article in journal (Refereed)
    Abstract [en]

    Although changes in phenology and species associations are relatively well-documented responses to global warming, the potential interactions between these phenomena are less well understood. In this study, we investigate the interactions between temperature, phenology (in terms of seasonal timing of larval growth) and host plant use in the polyphagous butterfly Polygonia c-album. We found that the hierarchy of larval performance on three natural host plants was not modified by a temperature increase as such. However, larval performance on each host plant and temperature treatment was affected by rearing season. Even though larvae performed better at the higher temperature regardless of the time of the rearing, relative differences between host plants changed with the season. For larvae reared late in the season, performance was always better on the herbaceous plant than on the woody plants. In this species, it is likely that a prolonged warming will lead to a shift from univoltinism to bivoltinism. The demonstrated interaction between host plant suitability and season means that such a shift is likely to lead to a shift in selective regime, favoring specialization on the herbaceous host. Based on our result, we suggest that host range evolution in response to temperature increase would in this species be highly contingent on whether the population undergoes a predicted shift from one to two generations. We discuss the effect of global warming on species associations and the outcome of asynchrony in rates of phenological change.

  • 5. Birkhofer, Klaus
    et al.
    Bylund, Helena
    Dalin, Peter
    Ferlian, Olga
    Gagic, Vesna
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Klapwijk, Maartje
    Mestre, Laia
    Roubinet, Eve
    Schroeder, Martin
    Stenberg, Johan A.
    Porcel, Mario
    Björkman, Christer
    Jonsson, Mattias
    Methods to identify the prey of invertebrate predators in terrestrial field studies2017In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 7, no 6, p. 1942-1953Article, review/survey (Refereed)
    Abstract [en]

    Predation is an interaction during which an organism kills and feeds on another organism. Past and current interest in studying predation in terrestrial habitats has yielded a number of methods to assess invertebrate predation events in terrestrial ecosystems. We provide a decision tree to select appropriate methods for individual studies. For each method, we then present a short introduction, key examples for applications, advantages and disadvantages, and an outlook to future refinements. Video and, to a lesser extent, live observations are recommended in studies that address behavioral aspects of predator-prey interactions or focus on per capita predation rates. Cage studies are only appropriate for small predator species, but often suffer from a bias via cage effects. The use of prey baits or analyses of prey remains are cheaper than other methods and have the potential to provide per capita predation estimates. These advantages often come at the cost of low taxonomic specificity. Molecular methods provide reliable estimates at a fine level of taxonomic resolution and are free of observer bias for predator species of any size. However, the current PCR-based methods lack the ability to estimate predation rates for individual predators and are more expensive than other methods. Molecular and stable isotope analyses are best suited to address systems that include a range of predator and prey species. Our review of methods strongly suggests that while in many cases individual methods are sufficient to study specific questions, combinations of methods hold a high potential to provide more holistic insights into predation events. This review presents an overview of methods to researchers that are new to the field or to particular aspects of predation ecology and provides recommendations toward the subset of suitable methods to identify the prey of invertebrate predators in terrestrial field research.

  • 6.
    Fors, Lisa
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Mozuraitis, Raimondas
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Nature Research Centre, Lithuania.
    Blažytė‐Čereškienė, Laima
    Verschut, Thomas A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Selection by parasitoid females among closely related hosts based on volatiles: Identifying relevant chemical cues2018In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 8, no 6, p. 3219-3228Article in journal (Refereed)
    Abstract [en]

    Parasitoid fitness is influenced by the ability to overcome host defense strategies and by the ability of parasitoid females to select high-quality host individuals. When females are unable to differentiate among hosts, their fitness will decrease with an increasing abundance of resistant hosts. To understand the effect of mixed host populations on female fitness, it is therefore necessary to investigate the ability of female parasitoids to select among hosts. Here, we used behavioral assays, headspace volatile collection, and electrophysiology to study the ability of Asecodes parviclava to use olfactory cues to select between a susceptible host (Galerucella calmariensis) and a resistant host (Galerucella pusilla) from a distance. Our studies show that parasitoid females have the capacity to distinguish the two hosts and that the selection behavior is acquired through experiences during earlier life stages. Further, we identified two volatiles (-terpinolene and [E]--ocimene) which amounts differ between the two plant-herbivore systems and that caused behavioral and electrophysiological responses. The consequence of this selection behavior is that females have the capacity to avoid laying eggs in G.pusilla, where the egg mortality is higher due to much stronger immune responses toward A.parviclava than in larvae of G.calmariensis.

  • 7.
    George, Rushingisha
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Tanzania Fisheries Research Institute (TAFIRI), Tanzania .
    Gullström, Martin
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Mangora, Mwita M.
    Mtolera, Matern S. P.
    Björk, Mats
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    High midday temperature stress has stronger effects on biomass than on photosynthesis: A mesocosm experiment on four tropical seagrass species2018In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 8, no 9, p. 4508-4517Article in journal (Refereed)
    Abstract [en]

    The effect of repeated midday temperature stress on the photosynthetic performance and biomass production of seagrass was studied in a mesocosm setup with four common tropical species, including Thalassia hemprichii, Cymodocea serrulata, Enhalus acoroides, and Thalassodendron ciliatum. To mimic natural conditions during low tides, the plants were exposed to temperature spikes of different maximal temperatures, that is, ambient (29-33 degrees C), 34, 36, 40, and 45 degrees C, during three midday hours for seven consecutive days. At temperatures of up to 36 degrees C, all species could maintain full photosynthetic rates (measured as the electron transport rate, ETR) throughout the experiment without displaying any obvious photosynthetic stress responses (measured as declining maximal quantum yield, Fv/Fm). All species except T.ciliatum could also withstand 40 degrees C, and only at 45 degrees C did all species display significantly lower photosynthetic rates and declining Fv/Fm. Biomass estimation, however, revealed a different pattern, where significant losses of both above- and belowground seagrass biomass occurred in all species at both 40 and 45 degrees C (except for C.serrulata in the 40 degrees C treatment). Biomass losses were clearly higher in the shoots than in the belowground root-rhizome complex. The findings indicate that, although tropical seagrasses presently can cope with high midday temperature stress, a few degrees increase in maximum daily temperature could cause significant losses in seagrass biomass and productivity.

  • 8.
    Hambäck, Peter A.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Weingartner, Elisabeth
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Dalén, Love
    Wirta, Helena
    Roslin, Tomas
    Spatial subsidies in spider diets vary with shoreline structure: Complementary evidence from molecular diet analysis and stable isotopes2016In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 6, no 23, p. 8431-8439Article in journal (Refereed)
    Abstract [en]

    Inflow of matter and organisms may strongly affect the local density and diversity of organisms. This effect is particularly evident on shores where organisms with aquatic larval stages enter the terrestrial food web. The identities of such trophic links are not easily estimated as spiders, a dominant group of shoreline predator, have external digestion. We compared trophic links and the prey diversity of spiders on different shore types along the Baltic Sea: on open shores and on shores with a reed belt bordering the water. A priori, we hypothesized that the physical structure of the shoreline reduces the flow between ecosystem and the subsidies across the sea-land interface. To circumvent the lack of morphologically detectable remains of spider prey, we used a combination of stable isotope and molecular gut content analyses. The two tools used for diet analysis revealed complementary information on spider diets. The stable isotope analysis indicated that spiders on open shores had a marine signal of carbon isotopes, while spiders on reedy shores had a terrestrial signal. The molecular analysis revealed a diverse array of dipteran and lepidopteran prey, where spiders on open and reedy shores shared a similar diet with a comparable proportion of chironomids, the larvae of which live in the marine system. Comparing the methods suggests that differences in isotope composition of the two spider groups occurred because of differences in the chironomid diets: as larvae, chironomids of reedy shores likely fed on terrestrial detritus and acquired a terrestrial isotope signature, while chironomids of open shores utilized an algal diet and acquired a marine isotope signature. Our results illustrate how different methods of diet reconstruction may shed light on complementary aspects of nutrient transfer. Overall, they reveal that reed belts can reduce connectivity between habitats, but also function as a source of food for predators.

  • 9. Hudson, Lawrence N.
    et al.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Samnegård, Ulrika
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Lund University, Sweden.
    The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project2017In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 7, no 1, p. 145-188Article in journal (Refereed)
    Abstract [en]

    The PREDICTS project-Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)-has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.

  • 10. Hudson, Lawrence N.
    et al.
    Newbold, Tim
    Contu, Sara
    Hill, Samantha L. L.
    Lysenko, Igor
    De Palma, Adriana
    Phillips, Helen R. P.
    Senior, Rebecca A.
    Bennett, Dominic J.
    Booth, Hollie
    Choimes, Argyrios
    Correia, David L. P.
    Day, Julie
    Echeverria-Londono, Susy
    Garon, Morgan
    Harrison, Michelle L. K.
    Ingram, Daniel J.
    Jung, Martin
    Kemp, Victoria
    Kirkpatrick, Lucinda
    Martin, Callum D.
    Pan, Yuan
    White, Hannah J.
    Aben, Job
    Abrahamczyk, Stefan
    Adum, Gilbert B.
    Aguilar-Barquero, Virginia
    Aizen, Marcelo A.
    Ancrenaz, Marc
    Arbelaez-Cortes, Enrique
    Armbrecht, Inge
    Azhar, Badrul
    Azpiroz, Adrian B.
    Baeten, Lander
    Baldi, Andras
    Banks, John E.
    Barlow, Jos
    Batary, Peter
    Bates, Adam J.
    Bayne, Erin M.
    Beja, Pedro
    Berg, Ake
    Berry, Nicholas J.
    Bicknell, Jake E.
    Bihn, Jochen H.
    Boehning-Gaese, Katrin
    Boekhout, Teun
    Boutin, Celine
    Bouyer, Jeremy
    Brearley, Francis Q.
    Brito, Isabel
    Brunet, Joerg
    Buczkowski, Grzegorz
    Buscardo, Erika
    Cabra-Garcia, Jimmy
    Calvino-Cancela, Maria
    Cameron, Sydney A.
    Cancello, Eliana M.
    Carrijo, Tiago F.
    Carvalho, Anelena L.
    Castro, Helena
    Castro-Luna, Alejandro A.
    Cerda, Rolando
    Cerezo, Alexis
    Chauvat, Matthieu
    Clarke, Frank M.
    Cleary, Daniel F. R.
    Connop, Stuart P.
    D'Aniello, Biagio
    da Silva, Pedro Giovani
    Darvill, Ben
    Dauber, Jens
    Dejean, Alain
    Diekoetter, Tim
    Dominguez-Haydar, Yamileth
    Dormann, Carsten F.
    Dumont, Bertrand
    Dures, Simon G.
    Dynesius, Mats
    Edenius, Lars
    Elek, Zoltan
    Entling, Martin H.
    Farwig, Nina
    Fayle, Tom M.
    Felicioli, Antonio
    Felton, Annika M.
    Ficetola, Gentile F.
    Filgueiras, Bruno K. C.
    Fonte, Steven J.
    Fraser, Lauchlan H.
    Fukuda, Daisuke
    Furlani, Dario
    Ganzhorn, Joerg U.
    Garden, Jenni G.
    Gheler-Costa, Carla
    Giordani, Paolo
    Giordano, Simonetta
    Gottschalk, Marco S.
    Goulson, Dave
    Gove, Aaron D.
    Grogan, James
    Hanley, Mick E.
    Hanson, Thor
    Hashim, Nor R.
    Hawes, Joseph E.
    Hebert, Christian
    Helden, Alvin J.
    Henden, John-Andre
    Hernandez, Lionel
    Herzog, Felix
    Higuera-Diaz, Diego
    Hilje, Branko
    Horgan, Finbarr G.
    Horvath, Roland
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Isaacs-Cubides, Paola
    Ishitani, Masahiro
    Jacobs, Carmen T.
    Jaramillo, Victor J.
    Jauker, Birgit
    Jonsell, Mats
    Jung, Thomas S.
    Kapoor, Vena
    Kati, Vassiliki
    Katovai, Eric
    Kessler, Michael
    Knop, Eva
    Kolb, Annette
    Koroesi, Adam
    Lachat, Thibault
    Lantschner, Victoria
    Le Feon, Violette
    LeBuhn, Gretchen
    Legare, Jean-Philippe
    Letcher, Susan G.
    Littlewood, Nick A.
    Lopez-Quintero, Carlos A.
    Louhaichi, Mounir
    Loevei, Gabor L.
    Lucas-Borja, Manuel Esteban
    Luja, Victor H.
    Maeto, Kaoru
    Magura, Tibor
    Mallari, Neil Aldrin
    Marin-Spiotta, Erika
    Marshall, E. J. P.
    Martinez, Eliana
    Mayfield, Margaret M.
    Mikusinski, Grzegorz
    Milder, Jeffrey C.
    Miller, James R.
    Morales, Carolina L.
    Muchane, Mary N.
    Muchane, Muchai
    Naidoo, Robin
    Nakamura, Akihiro
    Naoe, Shoji
    Nates-Parra, Guiomar
    Navarrete Gutierrez, Dario A.
    Neuschulz, Eike L.
    Noreika, Norbertas
    Norfolk, Olivia
    Noriega, Jorge Ari
    Noeske, Nicole M.
    O'Dea, Niall
    Oduro, William
    Ofori-Boateng, Caleb
    Oke, Chris O.
    Osgathorpe, Lynne M.
    Paritsis, Juan
    Parra-H, Alejandro
    Pelegrin, Nicolas
    Peres, Carlos A.
    Persson, Anna S.
    Petanidou, Theodora
    Phalan, Ben
    Philips, T. Keith
    Poveda, Katja
    Power, Eileen F.
    Presley, Steven J.
    Proenca, Vania
    Quaranta, Marino
    Quintero, Carolina
    Redpath-Downing, Nicola A.
    Reid, J. Leighton
    Reis, Yana T.
    Ribeiro, Danilo B.
    Richardson, Barbara A.
    Richardson, Michael J.
    Robles, Carolina A.
    Roembke, Joerg
    Romero-Duque, Luz Piedad
    Rosselli, Loreta
    Rossiter, Stephen J.
    Roulston, T'ai H.
    Rousseau, Laurent
    Sadler, Jonathan P.
    Safian, Szabolcs
    Saldana-Vazquez, Romeo A.
    Samnegård, Ulrika
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Schueepp, Christof
    Schweiger, Oliver
    Sedlock, Jodi L.
    Shahabuddin, Ghazala
    Sheil, Douglas
    Silva, Fernando A. B.
    Slade, Eleanor M.
    Smith-Pardo, Allan H.
    Sodhi, Navjot S.
    Somarriba, Eduardo J.
    Sosa, Ramon A.
    Stout, Jane C.
    Struebig, Matthew J.
    Sung, Yik-Hei
    Threlfall, Caragh G.
    Tonietto, Rebecca
    Tothmeresz, Bela
    Tscharntke, Teja
    Turner, Edgar C.
    Tylianakis, Jason M.
    Vanbergen, Adam J.
    Vassilev, Kiril
    Verboven, Hans A. F.
    Vergara, Carlos H.
    Vergara, Pablo M.
    Verhulst, Jort
    Walker, Tony R.
    Wang, Yanping
    Watling, James I.
    Wells, Konstans
    Williams, Christopher D.
    Willig, Michael R.
    Woinarski, John C. Z.
    Wolf, Jan H. D.
    Woodcock, Ben A.
    Yu, Douglas W.
    Zaitsev, Andrey S.
    Collen, Ben
    Ewers, Rob M.
    Mace, Georgina M.
    Purves, Drew W.
    Scharlemann, Joern P. W.
    Purvis, Andy
    The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts2014In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 4, no 24, p. 4701-4735Article in journal (Refereed)
    Abstract [en]

    Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species' threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project - and avert - future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups - including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems - ). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.

  • 11.
    Kivelä, Sami M.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. University of Oulu, Finland.
    Välimäki, Panu
    Gotthard, Karl
    Stockholm University, Faculty of Science, Department of Zoology.
    Evolution of alternative insect life histories in stochastic seasonal environments2016In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 6, no 16, p. 5596-5613Article in journal (Refereed)
    Abstract [en]

    Deterministic seasonality can explain the evolution of alternative life history phenotypes (i.e., life history polyphenism) expressed in different generations emerging within the same year. However, the influence of stochastic variation on the expression of such life history polyphenisms in seasonal environments is insufficiently understood. Here, we use insects as a model and explore (1) the effects of stochastic variation in seasonality and (2) the life cycle on the degree of life history differentiation among the alternative developmental pathways of direct development and diapause (overwintering), and (3) the evolution of phenology. With numerical simulation, we determine the values of development (growth) time, growth rate, body size, reproductive effort, adult life span, and fecundity in both the overwintering and directly developing generations that maximize geometric mean fitness. The results suggest that natural selection favors the expression of alternative life histories in the alternative developmental pathways even when there is stochastic variation in seasonality, but that trait differentiation is affected by the developmental stage that overwinters. Increasing environmental unpredictability induced a switch to a bet-hedging type of life history strategy, which is consistent with general life history theory. Bet-hedging appeared in our study system as reduced expression of the direct development phenotype, with associated changes in life history phenotypes, because the fitness value of direct development is highly variable in uncertain environments. Our main result is that seasonality itself is a key factor promoting the evolution of seasonally polyphenic life histories but that environmental stochasticity may modulate the expression of life history phenotypes.

  • 12.
    Kodandaramaiah, Ullasa
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Indian Institute of Science Education & Research (IISER), India.
    Lindenfors, Patrik
    Stockholm University, Faculty of Science, Department of Zoology.
    Tullberg, Birgitta S.
    Stockholm University, Faculty of Science, Department of Zoology.
    Deflective and intimidating eyespots: a comparative study of eyespot size and position in Junonia butterflies2013In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 3, no 13, p. 4518-4524Article in journal (Refereed)
    Abstract [en]

    Eyespots are conspicuous circular features found on the wings of several lepidopteran insects. Two prominent hypotheses have been put forth explaining their function in an antipredatory role. The deflection hypothesis posits that eyespots enhance survival in direct physical encounters with predators by deflecting attacks away from vital parts of the body, whereas the intimidation hypothesis posits that eyespots are advantageous by scaring away a potential predator before an attack. In the light of these two hypotheses, we investigated the evolution of eyespot size and its interaction with position and number within a phylogenetic context in a group of butterflies belonging to the genus Junonia. We found that larger eyespots tend to be found individually, rather than in serial dispositions. Larger size and conspicuousness make intimidating eyespots more effective, and thus, we suggest that our results support an intimidation function in some species of Junonia with solitary eyespots. Our results also show that smaller eyespots in Junonia are located closer to the wing margin, thus supporting predictions of the deflection hypothesis. The interplay between size, position, and arrangement of eyespots in relation to antipredation and possibly sexual selection, promises to be an interesting field of research in the future. Similarly, further comparative work on the evolution of absolute eyespot size in natural populations of other butterfly groups is needed.

  • 13.
    Kodandaramaiah, Ullasa
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Indian Institute of Science Education & Research (IISER) - Thiruvananthapuram.
    Simonsen, Thomas J.
    Bromilow, Sean
    Wahlberg, Niklas
    Sperling, Felix
    Deceptive single-locus taxonomy and phylogeography: Wolbachia-associated divergence in mitochondrial DNA is not reflected in morphology and nuclear markers in a butterfly species2013In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 3, no 16, p. 5167-5176Article in journal (Refereed)
    Abstract [en]

    The satyrine butterfly Coenonympha tullia (Nymphalidae: Satyrinae) displays a deep split between two mitochondrial clades, one restricted to northern Alberta, Canada, and the other found throughout Alberta and across North America. We confirm this deep divide and test hypotheses explaining its phylogeographic structure. Neither genitalia morphology nor nuclear gene sequence supports cryptic species as an explanation, instead indicating differences between nuclear and mitochondrial genome histories. Sex-biased dispersal is unlikely to cause such mito-nuclear differences; however, selective sweeps by reproductive parasites could have led to this conflict. About half of the tested samples were infected by Wolbachia bacteria. Using multilocus strain typing for three Wolbachia genes, we show that the divergent mitochondrial clades are associated with two different Wolbachia strains, supporting the hypothesis that the mito-nuclear differences resulted from selection on the mitochondrial genome due to selective sweeps by Wolbachia strains.

  • 14.
    Kubrak, Olga I.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology.
    Flatt, Thomas
    Nässel, Dick R.
    Stockholm University, Faculty of Science, Department of Zoology.
    Leimar, Olof
    Stockholm University, Faculty of Science, Department of Zoology.
    Adaptation to fluctuating environments in a selection experiment with Drosophila melanogaster2017In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 7, no 11, p. 3796-3807Article in journal (Refereed)
    Abstract [en]

    A fundamental question in life-history evolution is how organisms cope with fluctuating environments, including variation between stressful and benign conditions. For short-lived organisms, environments commonly vary between generations. Using a novel experimental design, we exposed wild-derived Drosophila melanogaster to three different selection regimes: one where generations alternated between starvation and benign conditions, and starvation was always preceded by early exposure to cold; another where starvation and benign conditions alternated in the same way, but cold shock sometimes preceded starvation and sometimes benign conditions; and a third where conditions were always benign. Using six replicate populations per selection regime, we found that selected flies increased their starvation resistance, most strongly for the regime where cold and starvation were reliably combined, and this occurred without decreased fecundity or extended developmental time. The selected flies became stress resistant, displayed a pronounced increase in early life food intake and resource storage. In contrast to previous experiments selecting for increased starvation resistance in D. melanogaster, we did not find increased storage of lipids as the main response, but instead that, in particular for females, storage of carbohydrates was more pronounced. We argue that faster mobilization of carbohydrates is advantageous in fluctuating environments and conclude that the phenotype that evolved in our experiment corresponds to a compromise between the requirements of stressful and benign environments.

  • 15.
    König, Malin A. E.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Butterfly oviposition preference is not related to larval performance on a polyploid herb2016In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 6, no 9, p. 2781-2789Article in journal (Refereed)
    Abstract [en]

    The preference-performance hypothesis predicts that female insects maximize their fitness by utilizing host plants which are associated with high larval performance. Still, studies with several insect species have failed to find a positive correlation between oviposition preference and larval performance. In the present study, we experimentally investigated the relationship between oviposition preferences and larval performance in the butterfly Anthocharis cardamines. Preferences were assessed using both cage experiments and field data on the proportion of host plant individuals utilized in natural populations. Larval performance was experimentally investigated using larvae descending from 419 oviposition events by 21 females on plants from 51 populations of two ploidy types of the perennial herb Cardamine pratensis. Neither ploidy type nor population identity influenced egg survival or larval development, but increased plant inflorescence size resulted in a larger final larval size. There was no correlation between female oviposition preference and egg survival or larval development under controlled conditions. Moreover, variation in larval performance among populations under controlled conditions was not correlated with the proportion of host plants utilized in the field. Lastly, first instar larvae added to plants rejected for oviposition by butterfly females during the preference experiment performed equally well as larvae growing on plants chosen for oviposition. The lack of a correlation between larval performance and oviposition preference for A. cardamines under both experimental and natural settings suggests that female host choice does not maximize the fitness of the individual offspring.

  • 16.
    König, Malin A. E.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Timing of flowering and intensity of attack by a butterfly herbivore in a polyploid herb2015In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 5, no 9, p. 1863-1872Article in journal (Refereed)
    Abstract [en]

    Timing of plant development both determines the abiotic conditions that the plant experiences and strongly influences the intensity of interactions with other organisms. Plants and herbivores differ in their response to environmental cues, and spatial and temporal variation in environmental conditions might influence the synchrony between host plants and herbivores, and the intensity of their interactions. We investigated whether differences in first day of flowering among and within 21 populations of the polyploid herb Cardamine pratensis influenced the frequency of oviposition by the butterfly Anthocharis cardamines during four study years. The proportion of plants that became oviposited upon differed among populations, but these differences were not related to mean flowering phenology within the population in any of the four study years. Attack rates in the field were also not correlated with resistance to oviposition estimated under controlled conditions. Within populations, the frequency of butterfly attack was higher in early-flowering individuals in two of the four study years, while there was no significant relationship in the other 2years. Larger plants were more likely to become oviposited upon in all 4years. The effects of first flowering day and size on the frequency of butterfly attack did not differ among populations. The results suggest that differences in attack intensities among populations are driven mainly by differences in the environmental context of populations while mean differences in plant traits play a minor role. The fact that within populations timing of flowering influenced the frequency of herbivore attack only in some years and suggests that herbivore-mediated selection on plant phenology differs among years, possibly because plants and herbivores respond differently to environmental cues.

  • 17.
    Lindenfors, Patrik
    Stockholm University, Faculty of Science, Department of Zoology.
    The green beards of language2013In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 3, no 4, p. 1104-1112Article in journal (Refereed)
    Abstract [en]

    Language transfers information on at least three levels; (1) what is said, (2) how it is said (what language is used), and, (3) that it is said (that speaker and listener both possess the ability to use language). The use of language is a form of honest cooperation on two of these levels; not necessarily on what is said, which can be deceitful, but always on how it is said and that it is said. This means that the language encoding and decoding systems had to evolve simultaneously, through mutual fitness benefits. Theoretical problems surrounding the evolution of cooperation disappear if a recognition system is present enabling cooperating individuals to identify each other if they are equipped with green beards. Here, I outline how both the biological and cultural aspects of language are bestowed with such recognition systems. The biological capacities required for language signal their presence through speech and understanding. This signaling cannot be invaded by false green beards because the traits and the signal of their presence are one and the same. However, the real usefulness of language comes from its potential to convey an infinite number of meanings through the dynamic handling of symbols through language itself. But any specific language also signals its presence to others through usage and understanding. Thus, languages themselves cannot be invaded by false green beards because, again, the trait and the signal of its presence are one and the same. These twin green beards, in both the biological and cultural realms, are unique to language.

  • 18. Magnusson, Magnus
    et al.
    Bergsten, Arvid
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Ecke, Frauke
    Bodin, Örjan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Bodin, Lennart
    Hörnfeldt, Birger
    Predicting grey-sided vole occurrence in northern Sweden at multiple spatial scales2013In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 3, no 13, p. 4365-4376Article in journal (Refereed)
    Abstract [en]

    Forestry is continually changing the habitats for many forest-dwelling species around the world. The grey-sided vole (Myodes rufocanus) has declined since the 1970s in forests of northern Sweden. Previous studies suggested that this might partly be caused by reduced focal forest patch size due to clear-cutting. Proximity and access to old pine forest and that microhabitats often contains stones have also been suggested previously but never been evaluated at multiple spatial scales. In a field study in 2010–2011 in northern Sweden, we investigated whether occurrence of grey-sided voles would be higher in (1) large focal patches of >60 years old forest, (2) in patches with high connectivity to sur- rounding patches, and (3) in patches in proximity to stone fields. We trapped animals in forest patches in two study areas (V€asterbotten and Norrbotten). At each trap station, we surveyed structural microhabitat characteristics. Land- scape-scale features were investigated using satellite-based forest data combined with geological maps. Unexpectedly, the vole was almost completely absent in Norrbotten. The trap sites in Norrbotten had a considerably lower amount of stone holes compared with sites with voles in V€asterbotten. We suggest this might help to explain the absence in Norrbotten. In V€asterbotten, the distance from forest patches with voles to stone fields was significantly shorter than from patches without voles. In addition, connectivity to surrounding patches and size of the focal forest patches was indeed related to the occurrence of grey-sided voles, with connectivity being the overall best predictor. Our results support previous findings on the importance of large forest patches, but also highlight the importance of connectivity for occurrence of grey-sided voles. The results further suggest that proximity to stone fields increase habitat quality of the forests for the vole and that the presence of stone fields enhances the voles’ ability to move between nearby forest patches through the matrix

  • 19. Marzal, Julia Carolina Segami
    et al.
    Rudh, Andreas
    Rogell, Björn
    Stockholm University, Faculty of Science, Department of Zoology.
    Ödeen, Anders
    Lovlie, Hanne
    Rosher, Charlotte
    Qvarnström, Anna
    Cryptic female Strawberry poison frogs experience elevated predation risk when associating with an aposematic partner2017In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 7, no 2, p. 744-750Article in journal (Refereed)
    Abstract [en]

    Population divergence in sexual signals may lead to speciation through prezygotic isolation. Sexual signals can change solely due to variation in the level of natural selection acting against conspicuousness. However, directional mate choice (i.e., favoring conspicuousness) across different environments may lead to gene flow between populations, thereby delaying or even preventing the evolution of reproductive barriers and speciation. In this study, we test whether natural selection through predation upon mate-choosing females can favor corresponding changes in mate preferences. Our study system, Oophaga pumilio, is an extremely color polymorphic neotropical frog with two distinctive antipredator strategies: aposematism and crypsis. The conspicuous coloration and calling behavior of aposematic males may attract both cryptic and aposematic females, but predation may select against cryptic females choosing aposematic males. We used an experimental approach where domestic fowl were encouraged to find digitized images of cryptic frogs at different distances from aposematic partners. We found that the estimated survival time of a cryptic frog was reduced when associating with an aposematic partner. Hence, predation may act as a direct selective force on female choice, favoring evolution of color assortative mating that, in turn, may strengthen the divergence in coloration that natural selection has generated.

  • 20.
    Olsen, Morten Tange
    et al.
    Stockholm University, Faculty of Science, Department of Genetics, Microbiology and Toxicology.
    Pampoulie, Christophe
    Danielsdottir, Anna K.
    Lidh, Emmelie
    Stockholm University, Faculty of Science, Department of Genetics, Microbiology and Toxicology.
    Berube, Martine
    Vikingsson, Gisli A.
    Palsbøll, Per J.
    Stockholm University, Faculty of Science, Department of Genetics, Microbiology and Toxicology.
    Fin whale MDH-1 and MPI allozyme variation is not reflected in the corresponding DNA sequences2014In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 4, no 10, p. 1787-1803Article in journal (Refereed)
    Abstract [en]

    The appeal of genetic inference methods to assess population genetic structure and guide management efforts is grounded in the correlation between the genetic similarity and gene flow among populations. Effects of such gene flow are typically genomewide; however, some loci may appear as outliers, displaying above or below average genetic divergence relative to the genomewide level. Above average population, genetic divergence may be due to divergent selection as a result of local adaptation. Consequently, substantial efforts have been directed toward such outlying loci in order to identify traits subject to local adaptation. Here, we report the results of an investigation into the molecular basis of the substantial degree of genetic divergence previously reported at allozyme loci among North Atlantic fin whale (Balaenoptera physalus) populations. We sequenced the exons encoding for the two most divergent allozyme loci (MDH-1 and MPI) and failed to detect any nonsynonymous substitutions. Following extensive error checking and analysis of additional bioinformatic and morphological data, we hypothesize that the observed allozyme polymorphisms may reflect phenotypic plasticity at the cellular level, perhaps as a response to nutritional stress. While such plasticity is intriguing in itself, and of fundamental evolutionary interest, our key finding is that the observed allozyme variation does not appear to be a result of genetic drift, migration, or selection on the MDH-1 and MPI exons themselves, stressing the importance of interpreting allozyme data with caution. As for North Atlantic fin whale population structure, our findings support the low levels of differentiation found in previous analyses of DNA nucleotide loci.

  • 21. Ord, Terry J.
    et al.
    Emblen, Jack
    Hagman, Mattias
    University of New South Wales Evolution and Ecology Research Centre and the School of Biological Kensington NSW, Australia.
    Shofner, Ryan
    Unruh, Sarah
    Manipulation of habitat isolation and area implicates deterministic factors and limited neutrality in community assembly2017In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 7, no 15, p. 5845-5860Article in journal (Refereed)
  • 22. Pfeifer, M.
    et al.
    Lefebvre, V.
    Gardner, Toby A.
    Stockholm University, Stockholm Environment Institute.
    Arroyo-Rodriguez, V.
    BIOFRAG – a new database for analyzing BIOdiversity responses to forest FRAGmentation2014In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 4, no 9, p. 1524-1537Article in journal (Refereed)
    Abstract [en]

    Habitat fragmentation studies have produced complex results that are challenging to synthesize. Inconsistencies among studies may result from variation in the choice of landscape metrics and response variables, which is often compounded by a lack of key statistical or methodological information. Collating primary datasets on biodiversity responses to fragmentation in a consistent and flexible database permits simple data retrieval for subsequent analyses. We present a relational database that links such field data to taxonomic nomenclature, spatial and temporal plot attributes, and environmental characteristics. Field assessments include measurements of the response(s) (e.g., presence, abundance, ground cover) of one or more species linked to plots in fragments within a partially forested landscape. The database currently holds 9830 unique species recorded in plots of 58 unique landscapes in six of eight realms: mammals 315, birds 1286, herptiles 460, insects 4521, spiders 204, other arthropods 85, gastropods 70, annelids 8, platyhelminthes 4, Onychophora 2, vascular plants 2112, nonvascular plants and lichens 320, and fungi 449. Three landscapes were sampled as long-term time series (>10 years). Seven hundred and eleven species are found in two or more landscapes. Consolidating the substantial amount of primary data available on biodiversity responses to fragmentation in the context of land-use change and natural disturbances is an essential part of understanding the effects of increasing anthropogenic pressures on land. The consistent format of this database facilitates testing of generalizations concerning biologic responses to fragmentation across diverse systems and taxa. It also allows the re-examination of existing datasets with alternative landscape metrics and robust statistical methods, for example, helping to address pseudo-replication problems. The database can thus help researchers in producing broad syntheses of the effects of land use. The database is dynamic and inclusive, and contributions from individual and large-scale data-collection efforts are welcome.

  • 23.
    Stålhandske, Sandra
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Lehmann, Philipp
    Stockholm University, Faculty of Science, Department of Zoology.
    Pruisscher, Peter
    Stockholm University, Faculty of Science, Department of Zoology.
    Leimar, Olof
    Stockholm University, Faculty of Science, Department of Zoology.
    Effect of winter cold duration on spring phenology of the orange tip butterfly, Anthocharis cardamines 2015In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 5, no 23, p. 5509-5520Article in journal (Refereed)
    Abstract [en]

    The effect of spring temperature on spring phenology is well understood in a wide range of taxa. However, studies on how winter conditions may affect spring phenology are underrepresented. Previous work on Anthocharis cardamines (orange tip butterfly) has shown population-specific reaction norms of spring development in relation to spring temperature and a speeding up of post-winter development with longer winter durations. In this experiment, we examined the effects of a greater and ecologically relevant range of winter durations on post-winter pupal development of A. cardamines of two populations from the United Kingdom and two from Sweden. By analyzing pupal weight loss and metabolic rate, we were able to separate the overall post-winter pupal development into diapause duration and post-diapause development. We found differences in the duration of cold needed to break diapause among populations, with the southern UK population requiring a shorter duration than the other populations. We also found that the overall post-winter pupal development time, following removal from winter cold, was negatively related to cold duration, through a combined effect of cold duration on diapause duration and on post-diapause development time. Longer cold durations also lead to higher population synchrony in hatching. For current winter durations in the field, the A. cardamines population of southern UK could have a reduced development rate and lower synchrony in emergence because of short winters. With future climate change, this might become an issue also for other populations. Differences in winter conditions in the field among these four populations are large enough to have driven local adaptation of characteristics controlling spring phenology in response to winter duration. The observed phenology of these populations depends on a combination of winter and spring temperatures; thus, both must be taken into account for accurate predictions of phenology.

  • 24.
    Stålstedt, Jeanette
    et al.
    Swedish Museum of Natural History, Sweden.
    Bergsten, Johannes
    Swedish Museum of Natural History, Sweden.
    Ronquist, Fredrik
    Swedish Museum of Natural History, Sweden.
    “Forms” of water mites (Acari: Hydrachnidia): intraspecificvariation or valid species?2013In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 3, no 10, p. 3415-3435Article in journal (Refereed)
    Abstract [en]

    In many groups of organisms, especially in the older literature, it has been common practice to recognize sympatrically occurring phenotypic variants of a species as “forms”. However, what these forms really represent often remains unclear, especially in poorly studied groups. With new algorithms for DNA-based species delimitation, the status of forms can be explicitly tested with molecular data. In this study, we test a number of what is now recognized as valid species of water mites (Hydrachnidia), but have in the past been treated as forms sympatrically occurring with their nominate species. We also test a form without prior taxonomical status, using DNA and morphometrics. The barcoding fragment of COI, nuclear 28S and quantitative analyses of morphological data were used to test whether these taxa merit species status, as suggested by several taxonomists. Our results confirm valid species. Genetic distances between the form and nominate species (Piona dispersa and Piona variabilis, COI 11%), as well as likelihood ratio tests under the general mixed-Yule coalescent model, supported that these are separately evolving lineages as defined by the unified species concept. In addition, they can be diagnosed with morphological characters. The study also reveals that some taxa genetically represent more than one species. We propose that P. dispersa are recognized as valid taxa at the species level. Unionicola minor (which may consist of several species), Piona stjordalensis, P. imminuta s. lat., and P. rotundoides are confirmed as species using this model. The results also imply that future studies of other water mite species complexes are likely to reveal many more genetically and morphologically distinct species.

  • 25. Tsuboi, Masahito
    et al.
    Shoji, Jun
    Sogabe, Atsushi
    Ahnesjö, Ingrid
    Kolm, Niclas
    Stockholm University, Faculty of Science, Department of Zoology.
    Within species support for the expensive tissue hypothesis: a negative association between brain size and visceral fat storage in females of the Pacific seaweed pipefish2016In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 6, no 3, p. 647-655Article in journal (Refereed)
    Abstract [en]

    The brain is one of the most energetically expensive organs in the vertebrate body. Consequently, the high cost of brain development and maintenance is predicted to constrain adaptive brain size evolution (the expensive tissue hypothesis, ETH). Here, we test the ETH in a teleost fish with predominant female mating competition (reversed sex roles) and male pregnancy, the pacific seaweed pipefish Syngnathus schlegeli. The relative size of the brain and other energetically expensive organs (kidney, liver, heart, gut, visceral fat, and ovary/testis) was compared among three groups: pregnant males, nonpregnant males and egg producing females. Brood size in pregnant males was unrelated to brain size or the size of any other organ, whereas positive relationships were found between ovary size, kidney size, and liver size in females. Moreover, we found that the size of energetically expensive organs (brain, heart, gut, kidney, and liver) as well as the amount of visceral fat did not differ between pregnant and nonpregnant males. However, we found marked differences in relative size of the expensive organs between sexes. Females had larger liver and kidney than males, whereas males stored more visceral fat than females. Furthermore, in females we found a negative correlation between brain size and the amount of visceral fat, whereas in males, a positive trend between brain size and both liver and heart size was found. These results suggest that, while the majority of variation in the size of various expensive organs in this species likely reflects that individuals in good condition can afford to allocate resources to several organs, the cost of the expensive brain was visible in the visceral fat content of females, possibly due to the high costs associated with female egg production.

  • 26. Vehmaa, Anu
    et al.
    Hogfors, Hedvig
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Brutemark, Andreas
    Holmborn, Towe
    Engström-Öst, Jonna
    Projected marine climate change: effects on copepod oxidative status and reproduction2013In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 3, no 13, p. 4548-4557Article in journal (Refereed)
    Abstract [en]

    Zooplankton are an important link between primary producers and fish. Therefore, it is crucial to address their responses when predicting effects of climate change on pelagic ecosystems. For realistic community-level predictions, several biotic and abiotic climate-related variables should be examined in combination. We studied the combined effects of ocean acidification and global warming predicted for year 2100 with toxic cyanobacteria on the calanoid copepod, Acartia bifilosa. Acidification together with higher temperature reduced copepod antioxidant capacity. Higher temperature also decreased egg viability, nauplii development, and oxidative status. Exposure to cyanobacteria and its toxin had a negative effect on egg production but, a positive effect on oxidative status and egg viability, giving no net effects on viable egg production. Additionally, nauplii development was enhanced by the presence of cyanobacteria, which partially alleviated the otherwise negative effects of increased temperature and decreased pH on the copepod recruitment. The interactive effects of temperature, acidification, and cyanobacteria on copepods highlight the importance of testing combined effects of climate-related factors when predicting biological responses.

  • 27.
    Verschut, Thomas A.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Blažytė-Čereškienė, Laima
    Apšegaitė, Violeta
    Mozūraitis, Raimondas
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Institute of Ecology, Nature Research Centre, Lithuania.
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Natal origin affects host preference and larval performance relationships in a tritrophic system2017In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 7, p. 2079-2090Article in journal (Refereed)
    Abstract [en]

    Many insects face the challenge to select oviposition sites in heterogeneous environments where biotic and abiotic factors can change over time. One way to deal with this complexity is to use sensory experiences made during developmental stages to locate similar habitats or hosts in which larval development can be maximized. While various studies have investigated oviposition preference and larval performance relationships in insects, they have largely overlooked that sensory experiences made during the larval stage can affect such relationships. We addressed this issue by determining the role of natal experience on oviposition preference and larval performance relationships in a tritrophic system consisting of Galerucella sagittariae, feeding on the two host plants Potentilla palustris and Lysimachia thyrsiflora, and its larval parasitoid Asecodes lucens. We firstly determined whether differences in host-derived olfactory information could lead to divergent host selection, and secondly, whether host preference could result in higher larval performance based on the natal origin of the insects. Our results showed that the natal origin and the quality of the current host are both important aspects in oviposition preference and larval performance relationships. While we found a positive relationship between preference and performance of natal Lysimachia beetles, natal Potentilla larvae showed no such relationship and developed better on L. thyrsiflora. Additionally, the host selection by the parasitoid was mainly affected by the natal origin, while its performance was higher on Lysimachia larvae. With this study we showed that the relationship between oviposition preference and larval performance depends on the interplay between the natal origin of the female and the quality of the current host. However, without incorporating the full tritrophic context of these interactions, their implication in insect fitness and potential adaptation cannot be fully understood.

  • 28. Wang, Houshuai
    et al.
    Holloway, Jeremy D.
    Janz, Niklas
    Stockholm University, Faculty of Science, Department of Zoology.
    Braga, Mariana P.
    Stockholm University, Faculty of Science, Department of Zoology.
    Wahlberg, Niklas
    Wang, Min
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology.
    Polyphagy and diversification in tussock moths: Support for the oscillation hypothesis from extreme generalists2017In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 7, no 19, p. 7975-7986Article in journal (Refereed)
    Abstract [en]

    Theory on plasticity driving speciation, as applied to insect-plant interactions (the oscillation hypothesis), predicts more species in clades with higher diversity of host use, all else being equal. Previous support comes mainly from specialized herbivores such as butterflies, and plasticity theory suggests that there may be an upper host range limit where host diversity no longer promotes diversification. The tussock moths (Erebidae: Lymantriinae) are known for extreme levels of polyphagy. We demonstrate that this system is also very different from butterflies in terms of phylogenetic signal for polyphagy and for use of specific host orders. Yet we found support for the generality of the oscillation hypothesis, in that clades with higher diversity of host use were found to contain more species. These clades also consistently contained the most polyphagous single species. Comparing host use in Lymantriinae with related taxa shows that the taxon indeed stands out in terms of the frequency of polyphagous species. Comparative evidence suggests that this is most probably due to its nonfeeding adults, with polyphagy being part of a resulting life history syndrome. Our results indicate that even high levels of plasticity can drive diversification, at least when the levels oscillate over time.

  • 29. Winsa, Marie
    et al.
    Öckinger, Erik
    Bommarco, Riccardo
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Roberts, Stuart P. M.
    Wärnsberg, Johanna
    Bartomeus, Ignasi
    Sustained functional composition of pollinators in restored pastures despite slow functional restoration of plants2017In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 7, no 11, p. 3836-3846Article in journal (Refereed)
    Abstract [en]

    Habitat restoration is a key measure to counteract negative impacts on biodiversity from habitat loss and fragmentation. To assess success in restoring not only biodiversity, but also functionality of communities, we should take into account the re-assembly of species trait composition across taxa. Attaining such functional restoration would depend on the landscape context, vegetation structure, and time since restoration. We assessed how trait composition of plant and pollinator (bee and hoverfly) communities differ between abandoned, restored (formerly abandoned) or continuously grazed (intact) semi-natural pastures. In restored pastures, we also explored trait composition in relation to landscape context, vegetation structure, and pasture management history. Abandoned pastures differed from intact and restored pastures in trait composition of plant communities, and as expected, had lower abundances of species with traits associated with grazing adaptations. Further, plant trait composition in restored pastures became increasingly similar to that in intact pastures with increasing time since restoration. On the contrary, the trait composition of pollinator communities in both abandoned and restored pastures remained similar to intact pastures. The trait composition for both bees and hoverflies was influenced by flower abundance and, for bees, by connectivity to other intact grasslands in the landscape. The divergent responses across organism groups appeared to be mainly related to the limited dispersal ability and long individual life span in plants, the high mobility of pollinators, and the dependency of semi-natural habitat for bees. Our results, encompassing restoration effects on trait composition for multiple taxa along a gradient in both time (time since restoration) and space (connectivity), reveal how interacting communities of plants and pollinators are shaped by different trait-environmental relationships. Complete functional restoration of pastures needs for more detailed assessments of both plants dispersal in time and of resources available within pollinator dispersal range.

  • 30. Wirta, Helena K.
    et al.
    Vesterinen, Eero J.
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Weingartner, Elisabeth
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Rasmussen, Claus
    Reneerkens, Jeroen
    Schmidt, Niels M.
    Gilg, Olivier
    Roslin, Tomas
    Exposing the structure of an Arctic food web2015In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 5, no 17, p. 3842-3856Article in journal (Refereed)
    Abstract [en]

    How food webs are structured has major implications for their stability and dynamics. While poorly studied to date, arctic food webs are commonly assumed to be simple in structure, with few links per species. If this is the case, then different parts of the web may be weakly connected to each other, with populations and species united by only a low number of links. We provide the first highly resolved description of trophic link structure for a large part of a high-arctic food web. For this purpose, we apply a combination of recent techniques to describing the links between three predator guilds (insectivorous birds, spiders, and lepidopteran parasitoids) and their two dominant prey orders (Diptera and Lepidoptera). The resultant web shows a dense link structure and no compartmentalization or modularity across the three predator guilds. Thus, both individual predators and predator guilds tap heavily into the prey community of each other, offering versatile scope for indirect interactions across different parts of the web. The current description of a first but single arctic web may serve as a benchmark toward which to gauge future webs resolved by similar techniques. Targeting an unusual breadth of predator guilds, and relying on techniques with a high resolution, it suggests that species in this web are closely connected. Thus, our findings call for similar explorations of link structure across multiple guilds in both arctic and other webs. From an applied perspective, our description of an arctic web suggests new avenues for understanding how arctic food webs are built and function and of how they respond to current climate change. It suggests that to comprehend the community-level consequences of rapid arctic warming, we should turn from analyses of populations, population pairs, and isolated predator-prey interactions to considering the full set of interacting species.

  • 31. Zeng, Yu
    et al.
    Lou, Shang Ling
    Liao, Wen Bo
    Jehle, Robert
    Kotrschal, Alexander
    Stockholm University, Faculty of Science, Department of Zoology.
    Sexual selection impacts brain anatomy in frogs and toads2016In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 6, no 19, p. 7070-7079Article in journal (Refereed)
    Abstract [en]

    Natural selection is a major force in the evolution of vertebrate brain size, but the role of sexual selection in brain size evolution remains enigmatic. At least two opposing schools of thought predict a relationship between sexual selection and brain size. Sexual selection should facilitate the evolution of larger brains because better cognitive abilities may aid the competition for mates. However, it may also restrict brain size evolution due to energetic trade-offs between brain tissue and sexually selected traits. Here, we examined the patterns of selection on brain size and brain anatomy in male anurans (frogs and toads), a group where the strength of sexual selection differs markedly among species, using a phylogenetically controlled generalized least-squared (PGLS) regression analyses. The analysis revealed that in 43 Chinese anuran species, neither mating system, nor type of courtship, or testes mass was significantly associated with relative brain size. While none of those factors related to the relative size of olfactory nerves, optic tecta, telencephalon, and cerebellum, the olfactory bulbs were relatively larger in monogamous species and those using calls during courtship. Our findings support the mosaic model of brain evolution and suggest that while the investigated aspects of sexual selection do not seem to play a prominent role in the evolution of brain size of anurans, they do impact their brain anatomy.

1 - 31 of 31
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