Change search
Refine search result
1 - 21 of 21
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Auffret, Alistair G.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Aggemyr, Elsa
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Spatial scale and specialization affect how biogeography and functional traits predict long-term patterns of community turnover2017In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 31, no 2, p. 436-443Article in journal (Refereed)
    Abstract [en]

    1. Immigration, extirpation and persistence of individual populations of species are key processes determining community responses to environmental change. However, they are difficult to study over long time periods without corresponding historical and modern-day species occurrences.

    2. We used historical and present-day plant species occurrence data from two different spatial scales (resolutions) to investigate the plant community turnover during the 20th century in a Baltic Sea archipelago. Patterns of turnover were analysed in relation to plant functional traits relating to dispersal and competition/persistence, as well as biogeographical variables.

    3. Turnover was largely driven by interactions between functional traits and measures of area, connectivity and distance to mainland. However, the combinations of traits and biogeographical variables that were most important for predicting immigration and extirpation differed between data sets, and between species associated with grassland management and the entire species pool.

    4. Taller plants were more likely to persist regardless of scale and biogeography, reflecting the grazing abandonment that occurred in the study area. Interactions between dispersal traits and biogeography were related to immigrations when the entire species pool was considered. However, increased dispersal potential, a smaller island size and increasing distance to mainland combined to promote extirpations in management-associated species. A perennial life span and seed banking contributed to species persistence. At the larger spatial scale, trait-driven turnover was not mediated by the biogeographical context.

    5. We showed that it is important to consider functional traits, biogeographical variables and their interactions when analysing community turnover over time. Furthermore, we found that the understanding of how combinations of traits and biogeography predict turnover depends on the source and spatial scale of the available data, and the species pool analysed.

  • 2. Bejarano, Sonia
    et al.
    Jouffray, Jean-Baptiste
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Royal Swedish Academy of Sciences, Sweden.
    Chollett, Iliana
    Allen, Robert
    Roff, George
    Marshell, Alyssa
    Steneck, Robert
    Ferse, Sebastian C. A.
    Mumby, Peter J.
    The shape of success in a turbulent world: wave exposure filtering of coral reef herbivory2017In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 31, no 6, p. 1312-1324Article, review/survey (Refereed)
    Abstract [en]

    While environmental filters are well-known factors influencing community assembly, the extent to which these modify species functions, and entire ecosystem processes, is poorly understood. Focusing on a high-diversity system, we ask whether environmental filtering has ecosystem-wide effects beyond community assembly. We characterise a coral reef herbivorous fish community for swimming performance based on ten functional traits derived from fish morphology. We then investigate whether wave exposure modifies the functional make-up of herbivory, and the absolute and relative feeding frequency of distinct feeding functional groups. Herbivorous fish species conformed to either laterally compressed or fusiform body plans, which differ in their morphological design to minimise drag. High wave exposure selectively limited the feeding function of the deepest body shapes with highest caudal thrust efficiency, and favoured fusiform bodies irrespective of pectoral fin shape. Traditionally recognised herbivore feeding functional groups (i.e. grazers-detritivores and scrapers-small excavators) differed in swimming performance, and in their capacity to feed consistently across levels of wave exposure. We therefore emphasise the distinctness of their ecological niche and functional complementarity. Species within the same feeding functional group also had contrasting responses to wave exposure. We thereby reveal a further ecological dimension of niche partitioning, and reiterate the risk of assuming functional redundancy among species with a common feeding mode. Contrasting responses of species within feeding functional roles (i.e. response diversity) allowed the preservation of critical trophic functions throughout the gradient (e.g. macroalgal browsing), and likely explained why overall levels of herbivory were robust to filtering. Whether ecosystem functioning will remain robust under the additive effects of environmental stress and human-induced disturbances remains to be tested.

  • 3.
    Burian, Alfred
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. University of Derby, UK.
    Grosse, Julia
    Winder, Monika
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Boschker, Henricus T. S.
    Nutrient deficiencies and the restriction of compensatory mechanisms in copepods2018In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 32, no 3, p. 636-647Article in journal (Refereed)
    Abstract [en]

    1. The flexible regulation of feeding behaviour and nutrient metabolism is a prerequisite for consumers to grow and survive under variable food conditions. Thus, it is essential to understand the ecological trade-offs that restrict regulatory mechanisms in consumers to evaluate the consequences of nutrient limitations for trophic interactions.

    2. Here, we assessed behavioural and physiological adjustments to nutrient deficiencies in copepods and examined whether energy limitation, food digestibility or co-limitation with a second nutrient restricted compensatory mechanisms.

    3. A combination of C-13-labelling and compound-specific stable isotope measurements revealed that copepods compensated nitrogen deficiencies by raising retention efficiencies of amino acids (AA). The costs of higher retention efficiencies were reflected in the doubling of structural fatty acids (FA), probably required for morphological adaptations of the gut. A depletion of highly unsaturated FA in storage lipids and their selective retention suggested that these FA became co-limiting and restricted a further increase in AA retention efficiencies.

    4. Copepods feeding on phosphorus-limited algae showed a marked increase in ingestion rates but were not fully able to compensate dietary deficiencies. The increase in ingestion rates was thereby not restricted by higher foraging costs because energy storage in copepods increased. Instead, thicker cell walls of nutrient-limited algae indicated that algal digestion resistance restricted the extent of surplus feeding.

    5. The strongly nutrient-specific response of copepods had large implications for recycling rates, growth efficiencies and the potential top-down control at the plant-animal interface. Compensatory mechanisms to mitigate nutrient deficiencies are therefore an essential aspect of trophic interactions and have the potential to alter the structure of food web.

  • 4. Capek, Petr
    et al.
    Kotas, Petr
    Manzoni, Stefano
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Santruckova, Hana
    Drivers of phosphorus limitation across soil microbial communities2016In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 30, no 10, p. 1705-1713Article in journal (Refereed)
    Abstract [en]

    Nutrient limitation of soil microbial communities controls the rates of plant litter and soil organic matter decomposition and nutrient mineralization, and as such, it is central to soil and ecosystem models. According to ecological stoichiometry theory, when the carbon (C)-to-nutrient (E) ratio of resources used by a microbial community is higher than a critical ratio (C:E-CR), that nutrient is limiting. The C-to-phosphorus (P) critical ratio (C:P-CR) that determines P limitation is largely unknown for soils, and thus, it is the subject of our study. Our results show that the C:P-CR in widely different soils ranges from 26<bold></bold>6 to 465<bold></bold>1 or from 20<bold></bold>9 to 740<bold></bold>7 when accounting for 95% confidence intervals. Using constant or narrowly fluctuating C:P-CR in ecosystem models is therefore inaccurate. The C:P-CR cannot be simply predicted from microbial community C:P or available soil P. C:P-CR was only related to relative abundance of phospholipid fatty acids, which reflects microbial community structure and physiology. Our data suggest complex controls over microbial community C:P-CR. We further propose that using P storage compounds that allow the microbial community to temporarily buffer variability in available P can represent a widely adopted strategies across soils.

  • 5. Fulton, Christopher J.
    et al.
    Abesamis, Rene A.
    Berkström, Charlotte
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Swedish University of Agricultural Sciences, Sweden.
    Depczynski, Martial
    Graham, Nicholas A. J.
    Holmes, Thomas H.
    Kulbicki, Michel
    Noble, Mae M.
    Radford, Ben T.
    Tano, Stina
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Tinkler, Paul
    Wernberg, Thomas
    Wilson, Shaun K.
    Form and function of tropical macroalgal reefs in the Anthropocene2019In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 33, no 6, p. 989-999Article, review/survey (Refereed)
    Abstract [en]

    Tropical reefs have been subjected to a range of anthropogenic pressures such as global climate change, overfishing and eutrophication that have raised questions about the prominence of macroalgae on tropical reefs, whether they pose a threat to biodiversity, and how they may influence the function of tropical marine ecosystems. We synthesise current understanding of the structure and function of tropical macroalgal reefs and how they may support various ecosystem goods and services. We then forecast how key stressors may alter the role of macroalgal reefs in tropical seascapes of the Anthropocene. High levels of primary productivity from tropical canopy macroalgae, which rivals that of other key producers (e.g., corals and turf algae), can be widely dispersed across tropical seascapes to provide a boost of secondary productivity in a range of biomes that include coral reefs, and support periodic harvests of macroalgal biomass for industrial and agricultural uses. Complex macroalgal reefs that comprise a mixture of canopy and understorey taxa can also provide key habitats for a diverse community of epifauna, as well as juvenile and adult fishes that are the basis for important tropical fisheries. Key macroalgal taxa (e.g., Sargassum) that form complex macroalgal reefs are likely to be sensitive to future climate change. Increases in maximum sea temperature, in particular, could depress biomass production and/or drive phenological shifts in canopy formation that will affect their capacity to support tropical marine ecosystems. Macroalgal reefs can support a suite of tropical marine ecosystem functions when embedded within an interconnected mosaic of habitat types. Habitat connectivity is, therefore, essential if we are to maintain tropical marine biodiversity alongside key ecosystem goods and services. Consequently, complex macroalgal reefs should be treated as a key ecological asset in strategies for the conservation and management of diverse tropical seascapes. A plain language summary is available for this article.

  • 6.
    Hagman, Mattias
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Hayes, Andrew
    Capon, Rob
    Shine, Richard
    Alarm cues experienced by cane toad tadpoles affect post-metamorphic morphology and chemical defences2009In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 23, p. 126-132Article in journal (Refereed)
    Abstract [en]

     Summary: In many anuran species, larvae modify their developmental trajectories and behaviour in response to chemical cues that predict predator risk. Recent reviews highlight a dearth of studies on delayed (post-metamorphic) consequences of larval experience.

  • 2 We raised cane toad (Bufo marinus) tadpoles either under control conditions or in the presence of non-lethal predator cues (crushed conspecifics).
  • 3 Exposure to these chemical cues massively reduced size at metamorphosis, as predicted by theory. Parotoid glands were larger relative to body size in post-metamorphic animals from the experimental treatment, suggesting higher investment in chemical defences.
  • 4 Exposure to chemical cues from crushed conspecifics during larval life reduced total bufadienolide content of metamorphs, but increased amounts of one specific bufadienolide (bufalin).
  • 5 Hence, cane toads respond to perceived predation risk in the aquatic environment by metamorphosing at a smaller size and modifying their investment in defensive toxins during post-metamorphic life.
  • 6 Phenotypically flexible responses to larval conditions vary among amphibian taxa, and can involve significant carry-over effects into post-metamorphic life.
  • 7. Hasper, Thomas B.
    et al.
    Wallin, Göran
    Lamba, Shubhangi
    Hall, Marianne
    Jaramillo, Fernando
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Laudon, Hjalmar
    Linder, Sune
    Medhurst, Jane L.
    Räntfors, Mats
    Sigurdsson, Bjarni D.
    Uddling, Johan
    Water use by Swedish boreal forests in a changing climate2016In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 30, no 5, p. 690-699Article in journal (Refereed)
    Abstract [en]

    1. The rising levels of atmospheric carbon dioxide concentration ([CO2]) and temperature have the potential to substantially affect the terrestrial water and energy balance by altering the stomatal conductance and transpiration of trees. 2. Many models assume decreases in stomatal conductance and plant water use under rising [CO2], which has been used as a plausible explanation for the positive global trend in river run-off over the past century. Plant water use is, however, also affected by changes in temperature, precipitation and land use, and there is yet no consensus about the contribution of different drivers to temporal trends of evapotranspiration (ET) and river run-off. 3. In this study, we assessed water-use responses to climate change by using both long-term monitoring and experimental data in Swedish boreal forests. Historical trends and patterns in ET of large-scale boreal landscapes were determined using climate and run-off data from the past 50 years, while explicit tree water-use responses to elevated [CO2] and/or air temperature were examined in a whole-tree chamber experiment using mature Norway spruce (Picea abies (L.) Karst.) trees. 4. The results demonstrated that ET estimated from water budgets at the catchment scale increased by 18% over the past 50 years while run-off did not significantly change. The increase in ET was related to increasing precipitation and a steady increase in forest standing biomass over time. The whole-tree chamber experiment showed that Norway spruce trees did not save water under elevated [CO2] and that experimentally elevated air temperature did not increase transpiration as decreased stomatal conductance cancelled the effect of higher vapour pressure deficit in warmed air. 5. Our findings have important implications for projections of future water use of European boreal coniferous forests, indicating that changes in precipitation and standing biomass are more important than the effects of elevated [CO2] or temperature on transpiration rates.

  • 8.
    Johansson, Victor
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Swedish University of Agricultural Sciences, Sweden.
    Lönnell, Niklas
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Swedish University of Agricultural Sciences, Sweden.
    Rannik, Ullar
    Sundberg, Sebastian
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Air humidity thresholds trigger active moss spore release to extend dispersal in space and time2016In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 30, no 7, p. 1196-1204Article in journal (Refereed)
    Abstract [en]

    Understanding the complete dispersal process is important for making realistic predictions of species distributions, but mechanisms for diaspore release in wind-dispersed species are often unknown. However, diaspore release under conditions that increase the probability of longer dispersal distances and mechanisms that extend dispersal events in time may have evolutionary advantages. We quantified air humidity thresholds regulating spore release in the moss Brachythecium rutabulum. We also investigated the prevailing micrometeorological conditions when these thresholds occur in nature and how they affect dispersal distances up to 100m, using a mechanistic dispersal model. We show that moss spores were mainly released when the peristome teeth were opening, as relative air humidity (RH) decreased from high values to relatively low (mainly between 90% and 75% RH). This most often occurred in the morning, when wind speeds were relatively low. Surprisingly, the model predicted that an equally high proportion of the spores would travel distances beyond 100m (horizontally) when released in the wind conditions prevailing during events of RH decrease in the morning, that lead to peristome opening, as in the highest wind speeds. Moreover, a higher proportion of the spores reached high altitudes when released at the lower wind speeds during the morning compared to the higher speeds later in the day, indicating a possibility for extended dispersal distances when released in the morning. Dispersal in the morning is enhanced by a combination of a more unstable atmospheric surface layer that promotes vertical dispersal, and a lower wind speed that decreases the spore deposition probability onto the ground, compared to later in the day. Our study demonstrates an active spore release mechanism in response to diurnally changing air humidity. The mechanism may promote longer dispersal distances, because of enhanced vertical dispersal and because spores being released in the morning have more time to travel before the wind calms down at night. The mechanism also leads to a prolonged dispersal period over the season, which may be viewed as a risk spreading in time that ultimately also leads to a higher diversity of establishment conditions, dispersal distances and directions.

  • 9.
    Karlsson, Bengt
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Stjernholm, Fredrik
    Stockholm University, Faculty of Science, Department of Zoology.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Test of a developmental trade-off in a polyphenic butterfly: direct development favours reproductive output2008In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 22, no 1, p. 121-126Article in journal (Refereed)
    Abstract [en]

    1.Evolutionary theory predicts that resource allocation decisions taken during development are adjusted to an organism's life-history. These decisions may have irreversible effects on body design and strong fitness consequences. Holometabolous insects that have a long expected life span typically postpone reproduction, and so are expected to allocate resources for somatic maintenance prior to investing in reproduction. In contrast, insects that have a short expected life span are expected to allocate relatively less to soma and more to reproduction. In support of this theory, an earlier investigation of resources allocated to soma vs. reproductive reserves in the comma butterfly, Polygonia c-album, revealed that short-lived females indeed allocate more resources to reproductive reserves as compared to longer lived females that hibernate before reproduction suggesting that short-lived females should have higher fecundity.

    2. Here we test this prediction, using the comma butterfly as our study organism. Depending on daylength and temperature this butterfly produces one of two morphs: (i) a light summer morph that reproduces directly after adult eclosion and has a short expected life span of a couple of weeks; or (ii) a darker winter morph that normally lives for 8–9 months before the onset of reproduction. Our test is based on experimental manipulation that allowed us to induce reproduction without prior hibernation in winter morph comma butterflies, and comparing lifetime fecundity among three groups: (i) directly reproducing summer morph commas; (ii) directly reproducing winter morph commas; and (iii) winter morph commas reproducing after overwintering. This protocol allowed us to tease apart trade-offs during development and the hibernation period.

    3. The results showed that the short-lived summer morph had a substantially higher fecundity (total number of eggs = 586 ± 19, mean ± SE) than the winter morph females manipulated to reproduce without hibernation (total number of eggs = 334 ± 42). We argue that this is a consequence of a resource allocation trade-off during early development observed in this species; females with a short expected life as adults allocate relatively more of their resources to reproductive parts and thereby reach a higher reproductive output compared to females predisposed for a long adult life.

    4. There was no significant difference in lifetime fecundity between winter morph females that did, or did not, hibernate before reproduction. This suggests that the cost of hibernation per se is small and hence corroborates our conclusion that the life-history implemented trade-off made during early development underlies the lower reproductive output of the winter morph butterflies.

  • 10. Kivelä, Sami M.
    et al.
    Davis, Robert B.
    Esperk, Toomas
    Gotthard, Karl
    Stockholm University, Faculty of Science, Department of Zoology.
    Mutanen, Marko
    Valdma, Daniel
    Tammaru, Toomas
    Comparative analysis of larval growth in Lepidoptera reveals instar-level constraints2020In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435Article in journal (Refereed)
    Abstract [en]

    Juvenile growth trajectories evolve via the interplay of selective pressures on age and size at maturity, and developmental constraints. In insects, the moulting cycle is a major constraint on larval growth trajectories. Surface area to volume ratio of a larva decreases during growth, so renewal of certain surfaces by moulting is likely needed for the maintenance of physiological efficiency. A null hypothesis of isometry, implied by Dyar's Rule, would mean that the relative measures of growth remain constant across moults and instars. We studied ontogenetic changes and allometry in instar-specific characteristics of larval growth in 30 lepidopteran species in a phylogenetic comparative framework. Relative instar-specific mass increments (RMI) typically, but not invariably, decreased across instars. Ontogenetic change in RMIs varied among families with little within-family variation. End-of-instar growth deceleration (GD) became stronger with increasing body size across instars. Across-instar change in GD was conserved across taxa. Ontogenetic allometry was generally non-isometric in both RMI and GD. Results indicate that detailed studies on multiple species are needed for generalizations concerning growth trajectory evolution. Developmental and physiological mechanisms affecting growth trajectory evolution show different degrees of evolutionary conservatism, which must be incorporated into models of age and size at maturation.

  • 11.
    Kullberg, Cecilia
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology.
    Kaby, Ulrika
    Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Impaired flight ability prior to egg laying: A cost of being a capital breeder2005In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 19, no 1, p. 98-101Article in journal (Refereed)
    Abstract [en]
    • 1To investigate flight ability in captive Zebra Finches during reproduction we compared change in escape take-off ability and wing load of reproducing females with their mates and non-reproducing females when attacked by a model raptor.
    • 2Initially females had 18% higher wing load than males. Non-reproducing females and females that had started egg-laying flew slower than males. Reproducing females reduced wing load during egg-laying and flew faster when the clutch was completed. Non-breeding females remained on high wing load and flow slower than breeding females that had completed their clutch.
    • 3The increase in flight speed of breeding females was explained by a reduction in wing load during egg-laying.
    • 4Zebra Finches use accumulated reserves to produce eggs and pay a cost in terms of reduced flight ability, but then regain flight performance when the clutch is laid, probably demonstrating a predation cost of capital breeding in birds.
  • 12.
    Larsdotter-Mellström, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. University of Western Australia, Australia.
    Eriksson, Kerstin
    Stockholm University, Faculty of Science, Department of Zoology.
    Janz, Niklas
    Stockholm University, Faculty of Science, Department of Zoology.
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology.
    Carlsson, Mikael A.
    Stockholm University, Faculty of Science, Department of Zoology.
    Male butterflies use an anti-aphrodisiac pheromone to tailor ejaculates2016In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 30, no 2, p. 255-261Article in journal (Refereed)
    Abstract [en]

    When females mate with multiple partners, the risk of sperm competition depends on female mating history. To maximize fitness, males should adjust their mating investment according to this risk. In polyandrous butterflies, males transfer a large, nutritious ejaculate at mating. Larger ejaculates delay female remating and confer an advantage in sperm competition. We test whether male ejaculate size in the butterfly Pieris napi (Lepidoptera) varies with female mating history and thus sperm competition, and whether males assess sperm competition using the male-transferred anti-aphrodisiac methyl salicylate (MeS) as a cue. Both sexes responded physiologically to MeS in a dose-dependent manner. Males, however, were more sensitive to MeS than females. Ejaculates transferred by males mating with previously mated females were on average 26% larger than ejaculates transferred by males mating with virgin females, which conforms to sperm competition theory and indicates that males tailored their reproductive investment in response to sperm competition. Furthermore, ejaculates transferred by males mating with virgin females with artificially added MeS were also 26% larger than ejaculates transferred to control virgin females. Male-transferred anti-aphrodisiac pheromone not only functions as a male deterrent, but also carries information on female mating history and thus allows males to assess sperm competition.

    Download full text (pdf)
    fulltext
  • 13.
    Liljestrand Rönn, Johanna
    et al.
    Uppsala universitet.
    Katvala, Mari
    Arnqvist, Göran
    Correlated evolution between male and female primary reproductive characters in seed beetles2011In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 25, no 3, p. 634-640Article in journal (Refereed)
    Abstract [en]

    Because males and females of internally inseminating species interact directly during mating, adaptations in one sex in primary reproductive traits may trigger an evolutionary response in the other sex. Divergent postcopulatory sexual selection is considered the main driving force behind the evolution of many male and female reproductive traits, generating unique morphologies and physiologies that can contribute to reproductive isolation and, ultimately, speciation. 2. The focus of most previous studies of the evolution of primary reproductive characters has been male reproductive traits and ejaculate or sperm characteristics. However, in order to more fully understand the evolution of primary reproductive characters it is crucial that we also include female traits. 3. In insects, both the size and the composition of the ejaculate have been shown to influence female reproduction in numerous ways by affecting female remating behaviour, female fecundity and female life span. Here, we employ a phylogenetic comparative approach to assess correlated evolution between primary reproductive characters in males and those in females in a group of seed beetles (Chrysomelidae: Bruchinae). We further explore correlated evolution between ejaculate size and female fitness in these insects. 4. Our analyses revealed positive correlated evolution between three internal female reproductive traits and ejaculate weight as well as correlated evolution between ejaculate weight and female fitness. We discuss the causal factors behind this correlated evolution and suggest that the evolution of larger ejaculates, primarily by postcopulatory sexual selection, causes selection for larger primary sexual traits in females to allow females to more rapidly process ejaculates. This may then feedback on postcopulatory selection in males, reinforcing selection for larger ejaculates. 5. Our results show that the primary reproductive traits of males and females show correlated evolution and suggest that intersexual co-evolution may affect the evolution of female fitness.

  • 14.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Escape flight in moulting tree sparrows (Passer montanus)2001In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 15, no 1, p. 29-35Article in journal (Refereed)
    Abstract [en]
    • 1 Impaired predator evasion in birds as a cost in different life-history periods has received increasing attention in the last decade. Evasive abilities in birds have been found to be detrimentally affected by migratory fuel load, reproduction and moult. These results suggest that during these periods of their lives birds suffer from increased predation risk due to impaired evasive abilities.
    • 2 Theoretically, moult should have a detrimental effect on flight, and empirical work on starlings has shown impaired escape ability due to moult. However, a recent theoretical investigation found a surprisingly small effect of moult on flight in birds.
    • 3 In this study, 31 Tree Sparrows, a sedentary species with a slow moult, were used to investigate the effect of natural and manipulated moult on escape ability. No effect was found due to natural moult, however, when experimentally increasing moult gap size a strong negative effect was found.
    • 4  With support from empirical and theoretical work, this is the first study to suggest that slow moult may not increase predation risk due to impaired evasive abilities. Compensatory physiological adaptations probably cause this result and may be very important during moult.
    • 5 Predation risk is probably an important factor in the evolution of moult patterns and moult strategies.
  • 15.
    Lindestad, Olle
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    von Schmalensee, Loke
    Stockholm University, Faculty of Science, Department of Zoology.
    Lehmann, Philipp
    Stockholm University, Faculty of Science, Department of Zoology.
    Gotthard, Karl
    Stockholm University, Faculty of Science, Department of Zoology.
    Variation in butterfly diapause duration in relation to voltinism suggests adaptation to autumn warmth, not winter cold2020In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435Article in journal (Refereed)
    Abstract [en]

    The life cycles of animals vary in relation to local climate, as a result of both direct environmental effects and population-level variation in plastic responses. Insects often respond to the approach of winter by entering diapause, a hormonally programmed resting state where development is suspended and metabolism suppressed. Populations often differ in the duration of diapause, but the adaptive reasons for this are unclear. We performed a common-garden overwintering experiment with respirometric measurements in order to investigate the progression of diapause in the butterfly Pararge aegeria. Both the duration of diapause and the depth of metabolic suppression were shown to vary between populations. In contrast to previous results from various insects, diapause duration did not correspond to the local length of winter. Instead, the observed pattern was consistent with a scenario in which diapause duration is primarily a product of selection for suppressed metabolism during warm autumn conditions. The relationship between optimal diapause duration and the length of the warm season is complicated by variation in the number of yearly generations (voltinism). These results shed new light on variation in diapause ecophysiology, and highlight voltinism as an integrated product of selection at multiple points in the seasonal cycle. A free Plain Language Summary can be found within the Supporting Information of this article.

  • 16.
    Löwenborg, Kristin
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Shine, Richard
    Kärvemo, Simon
    Hagman, Mattias
    Stockholm University, Faculty of Science, Department of Zoology.
    Grass snakes exploit anthropogenic heat sources to overcome distributional limits imposed by oviparity2010In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 24, no 5, p. 1095-1102Article in journal (Refereed)
    Abstract [en]

    P>1. A lack of warm nest-sites prevents oviparous reptile species from reproducing in cool climates; such areas are dominated by viviparous species because sun-seeking pregnant females can maintain high temperatures for their developing offspring. 2. Our field and laboratory studies show that one oviparous species (the grass snake, Natrix natrix) escapes this cold-climate constraint (and hence, extends much further north in Europe than do other oviparous taxa) by ovipositing in a thermally distinctive man-made microhabitat (manure heaps on farms). 3. In the field, temperatures inside manure heaps averaged 30 center dot 7 degrees C, much higher than compost heaps (20 center dot 6 degrees C) or potential natural nest-sites under logs and rocks (15 center dot 5 degrees C). 4. In the laboratory, higher incubation temperatures not only hastened hatching, but also increased hatching success and modified the body sizes, colours, and locomotor abilities of hatchlings. Incubation temperatures typical of manure heaps (rather than alternative nest-sites) resulted in larger, faster offspring that hatched earlier in the season. 5. Thus, anthropogenic activities have generated potential nest-sites offering thermal regimes not naturally available in the region; and grass snakes have exploited that opportunity to escape the thermal limits that restrict geographic distributions of other oviparous reptile taxa.

  • 17.
    Plue, Jan
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. Södertörn University, Sweden.
    Kimberley, Adam
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Slotte, Tanja
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Interspecific variation in ploidy as a key plant trait outlining local extinction risks and community patterns in fragmented landscapes2018In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 32, no 8, p. 2095-2106Article in journal (Refereed)
    Abstract [en]

    1. Polyploidy is associated with a plethora of phenotypic and genetic changes yielding transformative effects on species' life-history and ecology. These biological attributes can contribute to the success of species on ecological timescales, as observed in the invasion success or rapid environmental and climatic adaptation of polyploids. However, to date there has been a distinct lack of empirical evidence linking species' local extinction risk, species distributions and community structure in fragmented landscapes with interspecific variation in ploidy. 2. We aimed to investigate the relationship between levels of habitat fragmentation and patterns in both diversity and the frequency of species with different ploidy levels. We included additional persistence-and dispersal related life-history traits, to establish the relative importance of ploidy in determining species richness and frequencies following habitat fragmentation. We therefore collected plant community presence-absence data and landscape data from grassland fragments from south-central Sweden. 3. Community-level analysis uncovered that interspecific variation in ploidy proved the strongest predictor of plant community species richness and turn-over across grassland fragments. Local extinction risk decreased as ploidy increased, with diploids most prone to local extinction. 4. In the species-level analysis, ploidy outweighed the combined explanatory power of commonly used life-history traits such as clonality, dispersal mechanism and mating system; key predictors of plant species distributions across fragmented landscapes. 5. Ploidy appears to capture parallel variation in a series of advantageous genetic and life-history mechanisms which operate on ecological timescales, emerging as the strongest predictor of local extinction risk even after accounting for variation in other crucial life-history traits. Our results therefore highlight the importance of genomic traits such as ploidy and total chromosome number as valuable factors explaining and predicting local extinction risk in fragmented landscapes.

  • 18.
    Vega-Trejo, Regina
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Australian National University, Australia.
    Fox, Rebecca J.
    Iglesias-Carrasco, Maider
    Head, Megan L.
    Jennions, Michael D.
    The effects of male age, sperm age and mating history on ejaculate senescence2019In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 33, no 7, p. 1267-1279Article in journal (Refereed)
    Abstract [en]

    1. In polyandrous species, a male's reproductive success depends on his ability to fertilize females, which, in turn, depends on his mating ability and his ability to produce competitive ejaculates. In many species, sperm traits differ between old and young males in ways that are likely to decrease the sperm competitiveness and fertility of older males. This age-ejaculate quality relationship is attributed to male ageing (i.e., senescence). 2. In a natural setting, male age and mating history are usually confounded: older males have usually mated and replenished their sperm supplies more often, so they have made a greater lifetime reproductive effort. In principle, the costs of reproduction, independent of any causal effect of male age, could generate an age-related decline in ejaculate quality. 3. To date, only a handful of studies have determined how male age, reproductive effort or their interaction affect ejaculate quality. Here, we experimentally manipulated the long-term mating history of 209 adult male mosquitofish (Gambusia holbrooki) over 14 weeks (N = 1,118 sperm samples). Males either had direct access to females and could mate freely, or had only visual and olfactory access to females. We documented the effect of mating history, adult male age (3, 9 and 14 weeks post-maturation) and their interaction on sperm velocity, sperm reserves and the rate of sperm replenishment. For sperm velocity, we additionally examined the effects of sperm age, because when older males mate less (or more) often than younger males there will be a correlation between mean sperm age and male age. 4. Sexually active males produced fewer sperm and replenished their sperm at a lower rate, and their sperm had lower velocity than males prevented from mating. Though older males produced more sperm, the rate of replenishment and velocity of their sperm was lower than the sperm of younger males. We also tested for a difference in the velocity of recently replenished (<24 hr) and older sperm (i.e., post-meiotic sperm senescence). There was no evidence that male age or mating history affects the extent of sperm senescence, but older sperm swam faster than recently produced sperm. Crucially, complex interactions are evident between male age and male mating history with respect to sperm number and the proportion of sperm that are replenished. 5. These results suggest that male age and mating history will interact to determine the reproductive success of a male under sperm competition. They reveal a complex relationship between a male's age and his ejaculate quality. We suggest that both mating history and sperm age should be controlled for when measuring the intrinsic rate of senescence for male reproductive traits if the goal is to isolate effects that are solely attributable to a male's chronological age.

  • 19.
    Verschut, Thomas A.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Becher, Paul G.
    Anderson, Peter
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Disentangling associational effects: both resource density and resource frequency affect search behaviour in complex environments2016In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 30, no 11, p. 1826-1833Article in journal (Refereed)
    Abstract [en]

    Neighbouring resources have been found to either decrease or increase the likelihood that a consumer organism attacks a focal resource. These phenomena are referred to as associational resistance (AR) and associational susceptibility (AS), respectively. While associational effects have been observed in various field studies, little is known on how resource heterogeneity can cause associational effects. We used a laboratory approach in which we studied the effects of resource density and frequency in the search behaviour of Drosophila melanogaster as a model organism for olfactory-guided behaviour in insects. We first determined whether D.melanogaster could discriminate between odour sources that differ quantitatively. Secondly, we determined what the effect of resource density and frequency was on the search behaviour of D.melanogaster by combining these resources into various patch arrangements. Finally, we used the outcome of our experiments to disentangle the role of resource density and frequency in associational effects. We found that D.melanogaster has the ability to discriminate between quantitatively different resources, but that the attraction to resource density is constrained by an optimum after which attraction decreases. Furthermore, in heterogeneous environments, flies showed a strong preference towards the more apparent resource, leading to AS for the more apparent resources and AR for the less apparent resource. The strength of this interaction increased with a decreasing frequency of the more apparent resource. These results imply that D.melanogaster mainly selects patches at the level of individual resources. Consequently, when a patch contains qualitatively different resources, the more apparent resource will attract a higher number of flies than the less apparent resource irrespective of the frequency of the apparent resource within the patch. Our study shows that associational effects can be explained by determining the hierarchical level at which a consumer selects its resources. When a consumer selects resources at the individual level rather than at the patch level, our results can be used to explain the population dynamics of host plants and their associated consumers under field conditions.

  • 20. Williams, Gareth J.
    et al.
    Graham, Nicholas A. J.
    Jouffray, Jean-Baptiste
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Royal Swedish Academy of Sciences, Sweden.
    Norström, Albert V.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Nyström, Magnus
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Gove, Jamison M.
    Heenan, Adel
    Wedding, Lisa M.
    Coral reef ecology in the Anthropocene2019In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 33, no 6, p. 1014-1022Article in journal (Refereed)
    Abstract [en]

    We are in the Anthropocene-an epoch where humans are the dominant force of planetary change. Ecosystems increasingly reflect rapid human-induced, socioeconomic and cultural selection rather than being a product of their surrounding natural biophysical setting. This poses the intriguing question: To what extent do existing ecological paradigms capture and explain the current ecological patterns and processes we observe? We argue that, although biophysical drivers still influence ecosystem structure and function at particular scales, their ability to offer predictive capacity over coupled social-ecological systems is increasingly compromised as we move further into the Anthropocene. Traditionally, the dynamics of coral reefs have been studied in response to their proximate drivers of change rather than their underlying socioeconomic and cultural drivers. We hypothesise this is limiting our ability to accurately predict spatial and temporal changes in coral reef ecosystem structure and function. We propose social-ecological macroecology as a novel approach within the field of coral reef ecology to a) identify the interactive effects of biophysical and socioeconomic and cultural drivers of coral reef ecosystems across spatial and temporal scales; b) test the robustness of existing coral reef paradigms; c) explore whether existing paradigms can be adapted to capture the dynamics of contemporary coral reefs; and d) if they cannot, develop novel coral reef social-ecological paradigms, where human dynamics are part of the paradigms rather than the drivers of them. Human socioeconomic and cultural processes must become embedded in coral reef ecological theory and practice as much as biophysical processes are today if we are to predict and manage these systems successfully in this era of rapid change. This necessary shift in our approach to coral reef ecology will be challenging and will require truly interdisciplinary collaborations between the natural and social sciences. A plain language summary is available for this article.

  • 21. Woodhead, Anna J.
    et al.
    Hicks, Christina C.
    Norström, Albert V.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Williams, Gareth J.
    Graham, Nicholas A. J.
    Coral reef ecosystem services in the Anthropocene2019In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 33, no 6, p. 1023-1034Article in journal (Refereed)
    Abstract [en]

    Coral reefs underpin a range of ecosystem goods and services that contribute to the well-being of millions of people. However, tropical coral reefs in the Anthropocene are likely to be functionally different from reefs in the past. In this perspective piece, we ask, what does the Anthropocene mean for the provision of ecosystem services from coral reefs? First, we provide examples of the provisioning, regulating, cultural and supporting services underpinned by coral reef ecosystems. We conclude that coral reef ecosystem service research has lagged behind multidisciplinary advances in broader ecosystem services science, such as an explicit recognition that interactions between social and ecological systems underpin ecosystem services. Second, drawing on tools from functional ecology, we outline how these social-ecological relationships can be incorporated into a mechanistic understanding of service provision and how this might be used to anticipate future changes in coral reef ecosystem services. Finally, we explore the emergence of novel reef ecosystem services, for example from tropicalized coastlines, or through changing technological connections to coral reefs. Indeed, when services are conceived as coming from social-ecological system dynamics, novelty in services can emerge from elements of the interactions between people and the ecosystem. This synthesis of the coral reef ecosystem services literature suggests the field is poorly prepared to understand the changing service provision anticipated in the Anthropocene. A new research agenda is needed that better connects reef functional ecology to ecosystem service provision. This research agenda should embrace more holistic approaches to ecosystem service research, recognizing them as co-produced by ecosystems and society. Importantly, the likelihood of novel ecosystem service configurations requires further conceptualization and empirical assessment. As with current ecosystem services, the loss or gain of services will not affect all people equally and must be understood in the context in which they occur. With the uncertainty surrounding the future of coral reefs in the Anthropocene, research exploring how the benefits to people change will be of great importance. A is available for this article.

  • 1 - 21 of 21
    CiteExportLink to result list
    Permanent link
    Cite
    Citation style
    • apa
    • ieee
    • modern-language-association-8th-edition
    • vancouver
    • Other style
    More styles
    Language
    • de-DE
    • en-GB
    • en-US
    • fi-FI
    • nn-NO
    • nn-NB
    • sv-SE
    • Other locale
    More languages
    Output format
    • html
    • text
    • asciidoc
    • rtf
    v. 2.35.10
    | | | |