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  • 1. Dussex, Nicolas
    et al.
    von Seth, Johanna
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Swedish Museum of Natural History, Sweden.
    Knapp, Michael
    Kardailsky, Olga
    Robertson, Bruce C.
    Dalén, Love
    Complete genomes of two extinct New Zealand passerines show responses to climate fluctuations but no evidence for genomic erosion prior to extinction2019Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 15, nr 9, artikel-id 20190491Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Human intervention, pre-human climate change (or a combination of both), as well as genetic effects, contribute to species extinctions. While many species from oceanic islands have gone extinct due to direct human impacts, the effects of pre-human climate change and human settlement on the genomic diversity of insular species and the role that loss of genomic diversity played in their extinctions remains largely unexplored. To address this question, we sequenced whole genomes of two extinct New Zealand passerines, the huia (Heteralocha acutirostris) and South Island kokako (Callaeas cinereus). Both species showed similar demographic trajectories throughout the Pleistocene. However, the South Island kokako continued to decline after the last glaciation, while the huia experienced some recovery. Moreover, there was no indication of inbreeding resulting from recent mating among closely related individuals in either species. This latter result indicates that population fragmentation associated with forest clearing by Maori may not have been strong enough to lead to an increase in inbreeding and exposure to genomic erosion. While genomic erosion may not have directly contributed to their extinctions, further habitat fragmentation and the introduction of mammalian predators by Europeans may have been an important driver of extinction in huia and South Island kokako.

  • 2. Gil-Romera, Graciela
    et al.
    Adolf, Carole
    Benito, Blas M.
    Bittner, Lucas
    Johansson, Maria U.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Grady, David A.
    Lamb, Henry F.
    Lemma, Bruk
    Fekadu, Mekbib
    Glaser, Bruno
    Mekonnen, Betelhem
    Sevilla-Callejo, Miguel
    Zech, Michael
    Zech, Wolfgang
    Miehe, Georg
    Long-term fire resilience of the Ericaceous Belt, Bale Mountains, Ethiopia2019Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 15, nr 7, artikel-id 20190357Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fire is the most frequent disturbance in the Ericaceous Belt (ca 3000-1300 m.a.s.l.), one of the most important plant communities of tropical African mountains. Through resprouting after fire, Erica establishes a positive fire feedback under certain burning regimes. However, present-day human activity in the Bale Mountains of Ethiopia includes fire and grating systems that may have a negative impact on the resilience of the ericaceous ecosystem. Current knowledge of Erica-fire relationships is based on studies of modern vegetation, lacking a longer time perspective that can shed light on baseline conditions for the fire feedback. We hypothesite that fire has influenced Erica communities in the Bale Mountains at millennial time-scales. To test this, we (1) identity the tire history ot the Bale Mountains through a pollen and charcoal record from Garba Guracha, a lake at 3950 m.a.s.l., and (2) describe the long-term bidirectional feedback between wildfire and Erica, which may control the ecosystem's resilience. Our results support fire occurrence in the area since ca 14 000 years ago, with particularly intense burning during the early Holocene, 10.8-6.0 cal ka BP. We show that a positive feedback between Erica abundance and fire occurrence was in operation throughout the Lateglacial and Holocene, and interpret the Ericaceous Bolt of the Ethiopian mountains as a long-term fire resilient ecosystem. We propose that controlled burning should be an integral part of landscape management in the Bale Mountains National Park.

  • 3.
    Kolm, Niclas
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Temrin, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Miklósi, Ádám
    Kubinyi, Enikő
    Garamszegi, László Zsolt
    The link between selection for function and human-directed play behaviour in dogs2020Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 16, nr 9, artikel-id 20200366Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Human-directed play behaviour is a distinct behavioural feature of domestic dogs. But the role that artificial selection for contemporary dog breeds has played for human-directed play behaviour remains elusive. Here, we investigate how human-directed play behaviour has evolved in relation to the selection for different functions, considering processes of shared ancestry and gene flow among the different breeds. We use the American Kennel Club (AKC) breed group categorization to reflect the major functional differences and combine this with observational data on human-directed play behaviour for over 132 breeds across 89 352 individuals from the Swedish Dog Mentality Assessment project. Our analyses demonstrate that ancestor dogs already showed intermediate levels of human-directed play behaviour, levels that are shared with several modern breed types. Herding and Sporting breeds display higher levels of human-directed play behaviour, statistically distinguishable from Non-sporting and Toy breeds. Our results suggest that human-directed play behaviour played a role in the early domestication of dogs and that subsequent artificial selection for function has been important for contemporary variation in a behavioural phenotype mediating the social bond with humans.

  • 4.
    Kotrschal, Alexander
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Corral-Lopez, Alberto
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Kolm, Niclas
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Large brains, short life: selection on brain size impacts intrinsic lifespan2019Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 15, nr 5, artikel-id 20190137Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The relationship between brain size and ageing is a paradox. The cognitive benefits of large brains should protect from extrinsic mortality and thus indirectly select for slower ageing. However, the substantial energetic cost of neural tissue may also impact the energetic budget of large-brained organisms, causing less investment in somatic maintenance and thereby faster ageing. While the positive association between brain size and survival in the wild is well established, no studies exist on the direct effects of brain size on ageing. Here we test how brain size influences intrinsic ageing in guppy (Poecilia reticulata) brain size selection lines with 12% difference in relative brain size. Measuring survival under benign conditions, we find that large-brained animals live 22% shorter than small-brained animals and the effect is similar in both males and females. Our results suggest a trade-off between investment into brain size and somatic maintenance. This implies that the link between brain size and ageing is contingent on the mechanism of mortality, and selection for positive correlations between brain size and ageing should occur mainly under cognition-driven survival benefits from increased brain size. We show that accelerated ageing can be a cost of evolving a larger brain.

  • 5.
    Lehmann, Philipp
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Stellenbosch University, South Africa .
    Javal, Marion
    Terblanche, John S.
    Oxygen limitation is not the cause of death during lethal heat exposure in an insect2019Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 15, nr 1, artikel-id 20180701Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Oxygen- and capacity-limited thermal tolerance (OCLTT) is a controversial hypothesis claiming to explain variation in, and mechanistically determine, animal thermal limits. The lack of support from Insecta is typically argued to be a consequence of their high-performance respiratory systems. However, no studies have reported internal body oxygen levels during thermal ramping so it is unclear if changes in ambient gas are partially or fully offset by a compensatory respiratory system. Here we provide such an assessment by simultaneously recording haemolymph oxygen (pO(2)) levels-as an approximation of tissue oxygenation-while experimentally manipulating ambient oxygen and subjecting organisms to thermal extremes in a series of thermolimit respirometry experiments using pupae of the butterfly Pieris napi. The main results are that while P. napi undergo large changes in haemolymph pO(2) that are positively correlated with experimental oxygen levels, haemolymph pO(2) is similar pre-and post-death during thermal assays. OCLTT predicts that reduction in body oxygen level should lead to a reduction in CTmax. Despite finding the former, there was no change in CTmax across a wide range of body oxygen levels. Thus, we argue that oxygen availability is not a functional determinant of the upper thermal limits in pupae of P. napi.

  • 6.
    Lindenfors, Patrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi. Stockholms universitet, Humanistiska fakulteten, Centrum för evolutionär kulturforskning.
    Neocortex evolution in primates: the 'social brain' is for females2005Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 1, s. 407-410Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    According to the social intelligence hypothesis, relative neocortex size should be directly related to the degree of social complexity. This hypothesis has found support in a number of comparative studies of group size. The relationship between neocortex and sociality is thought to exist either because relative neocortex size limits group size or because a larger group size selects for a larger neocortex. However, research on primate social evolution has indicated that male and female group sizes evolve in relation to different demands. While females mostly group according to conditions set by the environment, males instead simply go where the females are. Thus, any hypothesis relating to primate social evolution has to analyse its relationship with male and female group sizes separately. Since sex-specific neocortex sizes in primates are unavailable in sufficient quantity, I here instead present results from phylogenetic comparative analyses of unsexed relative neocortex sizes and female and male group sizes. These analyses show that while relative neocortex size is positively correlated with female group size, it is negatively, or not at all correlated with male group size. This indicates that the social intelligence hypothesis only applies to female sociality.

  • 7.
    Lindenfors, Patrik
    et al.
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur, Centrum för evolutionär kulturforskning. Institute for Futures Studies, Box 591, 101 31 Stockholm, Sweden;Centre for Cultural Evolution, Stockholm University, Sweden.
    Wartel, Andreas
    Centre for Cultural Evolution, Stockholm University, Sweden.
    Lind, Johan
    Centre for Cultural Evolution, Stockholm University, Sweden.
    ‘Dunbar's number’ deconstructed2021Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 17, nr 5, s. 1-4, artikel-id rsbl.2021.0158Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A widespread and popular belief posits that humans possess a cognitive capacity that is limited to keeping track of and maintaining stable relationships with approximately 150 people. This influential number, ‘Dunbar's number’, originates from an extrapolation of a regression line describing the relationship between relative neocortex size and group size in primates. Here, we test if there is statistical support for this idea. Our analyses on complementary datasets using different methods yield wildly different numbers. Bayesian and generalized least-squares phylogenetic methods generate approximations of average group sizes between 69–109 and 16–42, respectively. However, enormous 95% confidence intervals (4–520 and 2–336, respectively) imply that specifying any one number is futile. A cognitive limit on human group size cannot be derived in this manner.

    Ladda ner fulltext (pdf)
    Lindenfors-Wartel-Lind-2021-biol-lett.pdf
  • 8. Maklakov, Alexei A.
    et al.
    Immler, Simone
    Gonzalez-Voyer, Alejandro
    Rönn, Johanna
    Kolm, Niclas
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Brains and the city in passerine birds: re-analysis and confirmation of the original result2013Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, nr 6, artikel-id 20130859Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Our original paper [1] included two Bayesian analyses [2] of the association between brain size and the probability of a passerine species of bird breeding in the city centre—at the level of families and at the level of individual species—with both analyses suggesting the same pattern. It has since been brought to our attention that in one of the analyses at the level of individual species, the residual variance was not fixed to 1 resulting in overestimation of the variance. We re-ran the analysis using fixed residual variance and the results support the original conclusion that relative brain size is associated with breeding in the city centre (ln brain size: posterior mean, 324.53, 95% credibility interval, 52.61–601.35; ln body size: posterior mean, −276.22, 95% credibility interval, −490.60 to −70.32). Furthermore, we applied a complimentary approach using logistic regression to test whether brain size predicts breeding in the city centre (yes/no) without accounting for phylogeny. This analysis also resulted in a significant positive association between brain size and breeding in city centres (likelihood ratio tests: ln brain size: d.f. = 1, χ2 = 11.08, p = 0.0009; ln body size: d.f. = 1, χ2 = 11.26, p = 0.0008). Thus, our results are confirmed by both phylogenetic and non-phylogenetic analyses.

  • 9.
    Maklakov, Alexei
    et al.
    Uppsala Universitet.
    Immler, Simone
    Uppsala Universitet.
    Gonzalez-Voyer, Alejandro
    Rönn, Johanna
    Uppsala universitet.
    Kolm, Niclas
    Brains and the city: big-brained passerine birds succeed in urban environments2011Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 7, nr 5, s. 730-732Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Urban regions are among the most human-altered environments on Earth and they are poised for rapid expansion following population growth and migration. Identifying the biological traits that determine which species are likely to succeed in urbanized habitats is important for predicting global trends in biodiversity. We provide the first evidence for the intuitive yet untested hypothesis that relative brain size is a key factor predisposing animals to successful establishment in cities. We apply phylogenetic mixed modelling in a Bayesian framework to show that passerine species that succeed in colonizing at least one of 12 European cities are more likely to belong to big-brained lineages than species avoiding these urban areas. These data support findings linking relative brain size with the ability to persist in novel and changing environments in vertebrate populations, and have important implications for our understanding of recent trends in biodiversity.

  • 10.
    Mitchell, David J.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Vega-Trejo, Regina
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Kotrschal, Alexander
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Wageningen University, The Netherlands.
    Experimental translocations to low predation lead to non-parallel increases in relative brain size2020Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 16, nr 1, artikel-id 20190654Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Predation is a near ubiquitous factor of nature and a powerful selective force on prey. Moreover, it has recently emerged as an important driver in the evolution of brain anatomy, though population comparisons show ambiguous results with considerable unexplained variation. Here, we test the reproducibility of reduced predation on evolutionary trajectories of brain evolution. We make use of an introduction experiment, whereby guppies (Poecilia reticulata) from a single high predation stream were introduced to four low predation streams. After 8-9 years of natural selection in the wild and two generations of common garden conditions in the laboratory, we quantified brain anatomy. Relative brain region sizes did not differ between populations. However, we found a general increase and striking variation in relative brain size of introduced populations, which varied from no change to a 12.5% increase in relative brain weight, relative to the ancestral high predation population. We interpret this as evidence for non-parallel evolution, which implies a weak or inconsistent association of relative brain size with fitness in low predation sites. The evolution of brain anatomy appears sensitive to unknown environmental factors, or contingent on either chance events or historical legacies of environmental change.

  • 11. Ollivier, Morgane
    et al.
    Tresset, Anne
    Frantz, Laurent A. F.
    Bréhard, Stéphanie
    Bălăşescu, Adrian
    Mashkour, Marjan
    Boroneanţ, Adina
    Pionnier-Capitan, Maud
    Lebrasseur, Ophélie
    Arbogast, Rose-Marie
    Bartosiewicz, László
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur.
    Debue, Karyne
    Rabinovich, Rivka
    Sablin, Mikhail V.
    Larson, Greger
    Hänni, Catherine
    Hitte, Christophe
    Vigne, Jean-Denis
    Dogs accompanied humans during the Neolithic expansion into Europe2018Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 14, nr 10, artikel-id 20180286Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Near Eastern Neolithic farmers introduced several species of domestic plants and animals as they dispersed into Europe. Dogs were the only domestic species present in both Europe and the Near East prior to the Neolithic. Here, we assessed whether early Near Eastern dogs possessed a unique mitochondrial lineage that differentiated them from Mesolithic European populations. We then analysed mitochondrial DNA sequences from 99 ancient European and Near Eastern dogs spanning the Upper Palaeolithic to the Bronze Age to assess if incoming farmers brought Near Eastern dogs with them, or instead primarily adopted indigenous European dogs after they arrived. Our results show that European pre-Neolithic dogs all possessed the mitochondrial haplogroup C, and that the Neolithic and Post-Neolithic dogs associated with farmers from Southeastern Europe mainly possessed haplogroup D. Thus, the appearance of haplogroup D most probably resulted from the dissemination of dogs from the Near East into Europe. In Western and Northern Europe, the turnover is incomplete and haplogroup C persists well into the Chalcolithic at least. These results suggest that dogs were an integral component of the Neolithic farming package and a mitochondrial lineage associated with the Near East was introduced into Europe alongside pigs, cows, sheep and goats. It got diluted into the native dog population when reaching the Western and Northern margins of Europe.

  • 12.
    Peña, Carlos
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Wahlberg, Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Prehistorical climate change increased diversification of a group of butterflies2008Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 4, s. 274-278Artikel i tidskrift (Refereegranskat)
  • 13.
    Rydin, Catarina
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Bolinder, Kristina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Moonlight pollination in the gymnosperm Ephedra (Gnetales)2015Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, nr 4, artikel-id 20140993Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Most gymnosperms are wind-pollinated, but some are insect-pollinated, and in Ephedra (Gnetales), both wind pollination and insect pollination occur. Little is, however, known about mechanisms and evolution of pollination syndromes in gymnosperms. Based on four seasons of field studies, we show an unexpected correlation between pollination and the phases of the moon in one of our studied species, Ephedra foeminea. It is pollinated by dipterans and lepidopterans, most of them nocturnal, and its pollination coincides with the full moon of July. This may be adaptive in two ways. Many nocturnal insects navigate using the moon. Further, the spectacular reflection of the full-moonlight in the pollination drops is the only apparent means of nocturnal attraction of insects in these plants. In the sympatric but wind-pollinated Ephedra distachya, pollination is not correlated to the full moon but occurs at approximately the same dates every year. The lunar correlation has probably been lost in most species of Ephedra subsequent an evolutionary shift to wind pollination in the clade. When the services of insects are no longer needed for successful pollination, the adaptive value of correlating pollination with the full moon is lost, and conceivably also the trait.

  • 14. Tichit, Pierre
    et al.
    Alves-dos-Santos, Isabel
    Dacke, Marie
    Baird, Emily
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Lund University, Sweden.
    Accelerated landings in stingless bees are triggered by visual threshold cues2020Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 16, nr 8, artikel-id 20200437Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Most flying animals rely primarily on visual cues to coordinate and control their trajectory when landing. Studies of visually guided landing typically involve animals that decrease their speed before touchdown. Here, we investigate the control strategy of the stingless bee Scaptotrigona depilis, which instead accelerates when landing on its narrow hive entrance. By presenting artificial targets that resemble the entrance at different locations on the hive, we show that these accelerated landings are triggered by visual cues. We also found that S. depilis initiated landing and extended their legs when the angular size of the target reached a given threshold. Regardless of target size, the magnitude of acceleration was the same and the bees aimed for the same relative position on the target suggesting that S. depilis use a computationally simple but elegant ‘stereotyped' landing strategy that requires few visual cues.

  • 15. Tsuboi, Masahito
    et al.
    Gonzalez-Voyer, Alejandro
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi. Universidad Nacional Autonoma de Mexico, Mexico.
    Kolm, Niclas
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för etologi.
    Functional coupling constrains craniofacial diversification in Lake Tanganyika cichlids2015Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, nr 5, artikel-id 20141053Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Functional coupling, where a singlemorphological trait performs multiple functions, is a universal feature of organismal design. Theory suggests that functional coupling may constrain the rate of phenotypic evolution, yet empirical tests of this hypothesis are rare. In fish, the evolutionary transition from guarding the eggs on a sandy/rocky substrate (i.e. substrate guarding) to mouthbrooding introduces a novel function to the craniofacial system and offers an ideal opportunity to test the functional coupling hypothesis. Using a combination of geometric morphometrics and a recently developed phylogenetic comparative method, we found that head morphology evolution was 43% faster in substrate guarding species than in mouthbrooding species. Furthermore, for species in which females were solely responsible for mouthbrooding the males had a higher rate of head morphology evolution than in those with biparental mouthbrooding. Our results support the hypothesis that adaptations resulting in functional coupling constrain phenotypic evolution.

  • 16.
    Uggla, Caroline
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Sociologiska institutionen.
    Andersson, Gunnar
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Sociologiska institutionen.
    Higher divorce risk when mates are plentiful? Evidence from Denmark2018Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 14, nr 9, artikel-id 20180475Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Work from social and biological sciences has shown that adult sex ratios are associated with relationship behaviours. When partners are abundant, opportunities for mate switching may increase and relationship stability decrease. To date, most of the human literature has used regional areas at various levels of aggregation to define partner markets. But, in developed countries, many individuals of reproductive age spend a considerable amount of time outside their residential areas, and other measures may better capture the opportunities to meet a (new) partner. Here, we use Danish register data to test whether the sex ratio of the occupational sector is linked to divorce. Our data cover individuals in Denmark who married during 1981-2002 and we control for age at and duration of marriage, education and parity. Results support the prediction that a higher proportion of opposite-sex individuals in one's occupational sector is associated with higher divorce risk. This holds for both men and women, but associations are somewhat stronger for men and vary by education. Our results highlight the need to study demographic behaviours of men and women simultaneously, and to consider partner markets beyond geographical areas so that differing strategies for males and females may be examined.

  • 17.
    Valdiosera, C.
    et al.
    Centro UCM-ISCIII de Evolucio´n y Comportamiento Humanos,C/Sinesio Delgado 4, 28029 Madrid, Spain.
    Garcia, N.
    Centro UCM-ISCIII de Evolucio´n y Comportamiento Humanos,C/Sinesio Delgado 4, 28029 Madrid, Spain.
    Dalen, L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Smith, C.
    Departamento de Paleobiologı´a, Museo Nacional de Ciencias Naturales.
    Kahlke, R. D.
    Forschungsstation für Quartärpalä ontologie Weimar, ForschungsinstitutSenckenberg, Am Jakobskirchhof 4, 99423 Weimar, Germany.
    Liden, K.
    Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur. Stockholms universitet, Humanistiska fakulteten, Institutionen för arkeologi och antikens kultur, Arkeologiska forskningslaboratoriet.
    Angerbjörn, A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Arsuaga, J. L.
    Centro UCM-ISCIII de Evolucio´n y Comportamiento Humanos,C/Sinesio Delgado 4, 28029 Madrid, Spain.
    Götherström, A.
    Department of Evolutionary Biology, Uppsala University.
    Typing single polymorphic nucleotides in mitochondrial DNA as a way to access Middle Pleistocene DNA2006Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 2, nr 4, s. 601-603Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, we have used a technique designed to target short fragments containing informative mitochondrial substitutions to extend the temporal limits of DNA recovery and study the molecular phylogeny of Ursus deningeri. We present a cladistic analysis using DNA recovered from 400 kyr old U. deningeri remains, which demonstrates U. deningeri's relation to Ursus spelaeus. This study extends the limits of recovery from skeletal remains by almost 300 kyr. Plant material from permafrost environments has yielded DNA of this age in earlier studies, and our data suggest that DNA in teeth from cave environments may be equally well preserved.

  • 18. Wedell, Nina
    et al.
    Wiklund, Christer
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Bergström, Jonas
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Coevolution of non-fertile sperm and female receptivity in a butterfly.2009Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 5, nr 5, s. 678-81Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sexual conflict can promote rapid evolution of male and female reproductive traits. Males of many polyandrous butterflies transfer nutrients at mating that enhances female fecundity, but generates sexual conflict over female remating due to sperm competition. Butterflies produce both normal fertilizing sperm and large numbers of non-fertile sperm. In the green-veined white butterfly, Pieris napi, non-fertile sperm fill the females' sperm storage organ, switching off receptivity and thereby reducing female remating. There is genetic variation in the number of non-fertile sperm stored, which directly relates to the female's refractory period. There is also genetic variation in males' sperm production. Here, we show that females' refractory period and males' sperm production are genetically correlated using quantitative genetic and selection experiments. Thus selection on male manipulation may increase the frequency of susceptible females to such manipulations as a correlated response and vice versa.

  • 19. Zimova, Marketa
    et al.
    Moberg, Dick
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Mills, L. Scott
    Dietz, Andreas J.
    Angerbjörn, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Colour moult phenology and camouflage mismatch in polymorphic populations of Arctic foxes2022Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 18, nr 11, artikel-id 20220334Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Species that seasonally moult from brown to white to match snowy backgrounds become conspicuous and experience increased predation risk as snow cover duration declines. Long-term adaptation to camouflage mismatch in a changing climate might occur through phenotypic plasticity in colour moult phenology and or evolutionary shifts in moult rate or timing. Also, adaptation may include evolutionary shifts towards winter brown phenotypes that forgo the winter white moult. Most studies of these processes have occurred in winter white populations, with little attention to polymorphic populations with sympatric winter brown and winter white morphs. Here, we used remote camera traps to record moult phenology and mismatch in two polymorphic populations of Arctic foxes in Sweden over 2 years. We found that the colder, more northern population moulted earlier in the autumn and later in the spring. Next, foxes moulted earlier in the autumn and later in the spring during colder and snowier years. Finally, white foxes experienced relatively low camouflage mismatch while blue foxes were mismatched against snowy backgrounds most of the autumn through the spring. Because the brown-on-white mismatch imposes no evident costs, we predict that as snow duration decreases, increasing blue morph frequencies might help facilitate species persistence.

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