| 1. |
- Pizzari, T., et al.
(author)
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A novel test of the phenotype-linked fertility hypothesis reveals independent components of fertility
- 2004
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In: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970 .- 0962-8452 .- 1471-2954. ; 271:1534, s. 51-58
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Journal article (peer-reviewed)abstract
- The phenotype-linked fertility hypothesis predicts that male sexual ornaments signal fertilizing efficiency and that the coevolution of male ornaments and female preference for such ornaments is driven by female pursuit of fertility benefits. In addition, directional testicular asymmetry frequently observed in birds has been suggested to reflect fertilizing efficiency and to covary with ornament expression. However, the idea of a phenotypic relationship between male ornaments and fertilizing efficiency is often tested in populations where environmental effects mask the underlying genetic associations between ornaments and fertilizing efficiency implied by this idea. Here, we adopt a novel design, which increases genetic diversity through the crossing of two divergent populations while controlling for environmental effects, to test: (i) the phenotypic relationship between male ornaments and both, gonadal (testicular mass) and gametic (sperm quality) components of fertilizing efficiency, and (ii) the extent to which these components are phenotypically integrated in the fowl, Gallus gallus. We show that consistent with theory, the testosterone-dependent expression of a male ornament, the comb, predicted testicular mass. However, despite their functional inter-dependence, testicular mass and sperm quality were not phenotypically integrated. Consistent with this result, males of one parental population invested more in testicular and comb mass, whereas males of the other parental population had higher sperm quality. We found no evidence that directional testicular asymmetry covaried with ornament expression. These results shed new light on the evolutionary relationship between male fertilizing efficiency and ornaments. Although testosterone-dependent ornaments may covary with testicular mass and thus reflect sperm production rate, the lack of phenotypic integration between gonadal and gametic traits reveals that the expression of an ornament is unlikely to reflect the overall fertilizing efficiency of a male.
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| 2. |
- Smolla, Marco, et al.
(author)
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Underappreciated features of cultural evolution
- 2021
-
In: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954 .- 0962-8436 .- 1471-2970. ; 376:1828
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Journal article (peer-reviewed)abstract
- Cultural evolution theory has long been inspired by evolutionary biology. Conceptual analogies between biological and cultural evolution have led to the adoption of a range of formal theoretical approaches from population dynamics and genetics. However, this has resulted in a research programme with a strong focus on cultural transmission. Here, we contrast biological with cultural evolution, and highlight aspects of cultural evolution that have not received sufficient attention previously. We outline possible implications for evolutionary dynamics and argue that not taking them into account will limit our understanding of cultural systems. We propose twelve key questions for future research, among which are calls to improve our understanding of the combinatorial properties of cultural innovation, and the role of development and life history in cultural dynamics. Finally, we discuss how this vibrant research field can make progress by embracing its multidisciplinary nature.
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| 3. |
- Abbott, Jessica K.
(author)
-
Intra-locus sexual conflict and sexually antagonistic genetic variation in hermaphroditic animals
- 2011
-
In: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 278:1703, s. 161-169
-
Research review (peer-reviewed)abstract
- Intra-locus sexual conflict results when sex-specific selection pressures for a given trait act against the intra-sexual genetic correlation for that trait. It has been found in a wide variety of taxa in both laboratory and natural populations, but the importance of intra-locus sexual conflict and sexually antagonistic genetic variation in hermaphroditic organisms has rarely been considered. This is not so surprising given the conceptual and theoretical association of intra-locus sexual conflict with sexual dimorphism, but there is no a priori reason why intra-locus sexual conflict cannot occur in hermaphroditic organisms as well. Here, I discuss the potential for intra-locus sexual conflict in hermaphroditic animals and review the available evidence for such conflict, and for the existence of sexually antagonistic genetic variation in hermaphrodites. I argue that mutations with asymmetric effects are particularly likely to be important in mediating sexual antagonism in hermaphroditic organisms. Moreover, sexually antagonistic genetic variation is likely to play an important role in inter-individual variation in sex allocation and in transitions to and from gonochorism (separate sexes) in simultaneous hermaphrodites. I also describe how sequential hermaphrodites may experience a unique form of intra-locus sexual conflict via antagonistic pleiotropy. Finally, I conclude with some suggestions for further research.
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| 4. |
- Abbott, Jessica K., et al.
(author)
-
Sex chromosome evolution : Historical insights and future perspectives
- 2017
-
In: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 284:1854
-
Research review (peer-reviewed)abstract
- Many separate-sexed organisms have sex chromosomes controlling sex determination. Sex chromosomes often have reduced recombination, specialized (frequently sex-specific) gene content, dosage compensation and heteromorphic size. Research on sex determination and sex chromosome evolution has increased over the past decade and is today a very active field. However, some areas within the field have not received as much attention as others.We therefore believe that a historic overviewof key findings and empirical discoveries will put current thinking into context and help us better understand where to go next. Here, we present a timeline of important conceptual and analytical models, as well as empirical studies that have advanced the field and changed our understanding of the evolution of sex chromosomes. Finally, we highlight gaps in our knowledge so far and propose some specific areas within the field that we recommend a greater focus on in the future, including the role of ecology in sex chromosome evolution and newmultilocus models of sex chromosome divergence.
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| 5. |
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| 6. |
- Alerstam, Thomas, et al.
(author)
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A polar system of intercontinental bird migration
- 2007
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In: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 274:1625, s. 2523-2530
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Journal article (peer-reviewed)abstract
- Studies of birdmigration in the Beringia region of Alaska and eastern Siberia are of special interest for revealing the importance of bird migration between Eurasia and North America, for evaluating orientation principles used by the birds at polar latitudes and for understanding the evolutionary implications of intercontinental migratory connectivity among birds as well as their parasites. We used tracking radar placed onboard the ice-breaker Oden to register bird migratory flights from 30 July to 19 August 2005 and we encountered extensive birdmigration in the whole Beringia range from latitude 64 degrees N in Bering Strait up to latitude 75 degrees N far north of Wrangel Island, with eastward flights making up 79% of all track directions. The results from Beringia were used in combination with radar studies from the Arctic Ocean north of Siberia and in the Beaufort Sea to make a reconstruction of a major Siberian-American birdmigration system in a wide Arctic sector between longitudes 1108 E and 130 degrees W, spanning one-third of the entire circumpolar circle. This system was estimated to involve more than 2 million birds, mainly shorebirds, terns and skuas, flying across the Arctic Ocean at mean altitudes exceeding 1 km (maximum altitudes 3-5 km). Great circle orientation provided a significantly better fit with observed flight directions at 20 different sites and areas than constant geographical compass orientation. The long flights over the sea spanned 40-80 degrees of longitude, corresponding to distances and durations of 1400-2600 km and 26-48 hours, respectively. The birds continued from this eastward migration system over the Arctic Ocean into several different flyway systems at the American continents and the Pacific Ocean. Minimization of distances between tundra breeding sectors and northerly stopover sites, in combination with the Beringia glacial refugium and colonization history, seemed to be important for the evolution of this major polar bird migration system.
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| 7. |
- Alerstam, Thomas, et al.
(author)
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Convergent patterns of long-distance nocturnal migration in noctuid moths and passerine birds.
- 2011
-
In: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 278, s. 3074-3080
-
Journal article (peer-reviewed)abstract
- Vast numbers of insects and passerines achieve long-distance migrations between summer and winter locations by undertaking high-altitude nocturnal flights. Insects such as noctuid moths fly relatively slowly in relation to the surrounding air, with airspeeds approximately one-third of that of passerines. Thus, it has been widely assumed that windborne insect migrants will have comparatively little control over their migration speed and direction compared with migrant birds. We used radar to carry out the first comparative analyses of the flight behaviour and migratory strategies of insects and birds under nearly equivalent natural conditions. Contrary to expectations, noctuid moths attained almost identical ground speeds and travel directions compared with passerines, despite their very different flight powers and sensory capacities. Moths achieved fast travel speeds in seasonally appropriate migration directions by exploiting favourably directed winds and selecting flight altitudes that coincided with the fastest air streams. By contrast, passerines were less selective of wind conditions, relying on self-powered flight in their seasonally preferred direction, often with little or no tailwind assistance. Our results demonstrate that noctuid moths and passerines show contrasting risk-prone and risk-averse migratory strategies in relation to wind. Comparative studies of the flight behaviours of distantly related taxa are critically important for understanding the evolution of animal migration strategies.
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| 8. |
- Ameen, Carly, et al.
(author)
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Specialized sledge dogs accompanied Inuit dispersal across the North American Arctic
- 2019
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In: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 286:1916
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Journal article (peer-reviewed)abstract
- Domestic dogs have been central to life in the North American Arctic for millennia. The ancestors of the Inuit were the first to introduce the widespread usage of dog sledge transportation technology to the Americas, but whether the Inuit adopted local Palaeo-Inuit dogs or introduced a new dog population to the region remains unknown. To test these hypotheses, we generated mitochondrial DNA and geometric morphometric data of skull and dental elements from a total of 922 North American Arctic dogs and wolves spanning over 4500 years. Our analyses revealed that dogs from Inuit sites dating from 2000 BP possess morphological and genetic signatures that distinguish them from earlier Palaeo-Inuit dogs, and identified a novel mitochondrial clade in eastern Siberia and Alaska. The genetic legacy of these Inuit dogs survives today in modern Arctic sledge dogs despite phenotypic differences between archaeological and modern Arctic dogs. Together, our data reveal that Inuit dogs derive from a secondary pre-contact migration of dogs distinct from Palaeo-Inuit dogs, and probably aided the Inuit expansion across the North American Arctic beginning around 1000 BP.
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| 9. |
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| 10. |
- Andersen, K. H., et al.
(author)
-
Damped trophic cascades driven by fishing in model marine ecosystems
- 2010
-
In: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 277:1682, s. 795-802
-
Journal article (peer-reviewed)abstract
- The largest perturbation on upper trophic levels of many marine ecosystems stems from fishing. The reaction of the ecosystem goes beyond the trophic levels directly targeted by the fishery. This reaction has been described either as a change in slope of the overall size spectrum or as a trophic cascade triggered by the removal of top predators. Here we use a novel size- and trait-based model to explore how marine ecosystems might react to perturbations from different types of fishing pressure. The model explicitly resolves the whole life history of fish, from larvae to adults. The results show that fishing does not change the overall slope of the size spectrum, but depletes the largest individuals and induces trophic cascades. A trophic cascade can propagate both up and down in trophic levels driven by a combination of changes in predation mortality and food limitation. The cascade is damped as it comes further away from the perturbed trophic level. Fishing on several trophic levels leads to a disappearance of the signature of the trophic cascade. Differences in fishing patterns among ecosystems might influence whether a trophic cascade is observed.
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| 11. |
- Andersen, K. H., et al.
(author)
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Trophic and individual efficiencies of size-structured communities
- 2009
-
In: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 276:1654, s. 109-114
-
Journal article (peer-reviewed)abstract
- Individual and trophic efficiencies of size-structured communities are derived from mechanistically based principles at the individual level. The derivations are relevant for communities with a size-based trophic structure, i.e. where trophic level is strongly correlated with individual size as in many aquatic systems. The derivations are used to link Lindeman's trophic theory and trophic theory based on average individuals with explicit individual-level size spectrum theory. The trophic efficiency based on the transfer of mass between trophic levels through predator-prey interactions is demonstrated to be valid only when somatic growth can be ignored. Taking somatic growth into account yields an average individual growth efficiency that is smaller than the trophic efficiency.
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| 12. |
- Andersen, O., et al.
(author)
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Haemoglobin polymorphisms affect the oxygen-binding properties in Atlantic cod populations
- 2009
-
In: Proceedings of the Royal Society B-Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 276:1658, s. 833-841
-
Journal article (peer-reviewed)abstract
- A major challenge in evolutionary biology is to identify the genes underlying adaptation. The oxygen-transporting haemoglobins directly link external conditions with metabolic needs and therefore represent a unique system for studying environmental effects on molecular evolution. We have discovered two haemoglobin polymorphisms in Atlantic cod populations inhabiting varying temperature and oxygen regimes in the North Atlantic. Three-dimensional modelling of the tetrameric haemoglobin structure demonstrated that the two amino acid replacements Met55β1Val and Lys62β1Ala are located at crucial positions of the α1β1subunit interface and haem pocket, respectively. The replacements are proposed to affect the oxygen-binding properties by modifying the haemoglobin quaternary structure and electrostatic feature. Intriguingly, the same molecular mechanism for facilitating oxygen binding is found in avian species adapted to high altitudes, illustrating convergent evolution in water- and air-breathing vertebrates to reduction in environmental oxygen availability. Cod populations inhabiting the cold Arctic waters and the low-oxygen Baltic Sea seem well adapted to these conditions by possessing the high oxygen affinity Val55–Ala62 haplotype, while the temperature-insensitive Met55–Lys62 haplotype predominates in the southern populations. The distinct distributions of the functionally different haemoglobin variants indicate that the present biogeography of this ecologically and economically important species might be seriously affected by global warming.
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| 13. |
- Andersson, Jens, et al.
(author)
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Interactions between predator- and diet-induced phenotypic changes in body shape of crucian carp
- 2006
-
In: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 273:1585, s. 431-437
-
Journal article (peer-reviewed)abstract
- Predator cues and diet, when studied separately, have been shown to affect body shape of organisms. Previous studies show that the morphological responses to predator absence/presence and diet may be similar, and hence could confound the interpretation of the causes of morphological differences found between groups of individuals. In this study, we simultaneously examined the effect of these two factors on body shape and performance in crucian carp in a laboratory experiment. Crucian carp (Carassius carassius) developed a shallow body shape when feeding on zooplankton prey and a deep body shape when feeding on benthic chironomids. In addition, the presence of chemical cues from a pike predator affected body shape, where a shallow body shape was developed in the absence of pike and a deep body shape was developed in the presence of pike. Foraging activity was low in the presence of pike cues and when chironomids were given as prey. Our results thereby suggest that the change in body shape could be indirectly mediated through differences in foraging activity. Finally, the induced body shape changes affected the foraging efficiency, where crucians raised on a zooplankton diet or in the absence of pike cues had a higher foraging success on zooplankton compared to crucian raised on a chironomid diet or in the presence of pike. These results suggest that body changes in response to predators can be associated with a cost, in terms of competition for resources.
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| 14. |
- Andersson, Johan, et al.
(author)
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Sexual conflict and anti-aphrodisiac titre in a polyandrous butterfly : male ejaculate tailoring and absence of female control
- 2004
-
In: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 271:1550, s. 1765-1770
-
Journal article (peer-reviewed)abstract
- Males of the green-veined butterfly Pieris napi synthesize and transfer the volatile methyl salicylate (MeS) to females at mating, a substance that is emitted by non-virgin females when courted by males, curtailing courtship and decreasing the likelihood of female re-mating. The volatile is released when females display the 'mate-refusal' posture with spread wings and elevated abdomen, when courted by conspecific males. Here, we assess how the amount of MeS released by courted females changes over time since mating, and whether it is influenced by the frequency with which females display the mate-refusal posture. We also assess whether males tailor the anti-aphrodisiac content of ejaculates with respect to the expected degree of sperm competition, by comparing how males allocate MeS proportionately to first and second ejaculates in relation to ejaculate mass. The results show that females housed for 5 days in individual cages where they were able to fly and oviposit normally, released similar amounts of MeS. However, females housed together for the same period of time, causing them to frequently display the mate-refusal posture, released significantly lower levels of MeS than the individually housed females. This indicates that female display of the mate-refusal posture depletes their anti-aphrodisiac stores, and suggests that females are unable to voluntarily control their release of the anti-aphrodisiac. A comparison of relative proportion of MeS transferred by males in their first and second ejaculates showed that proportionately more MeS was allocated to the first ejaculate, in accordance with the idea that these are tailored to delay female re-mating.
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| 15. |
- Andersson, J., et al.
(author)
-
Sexual cooperation and conflict in butterflies : a male-transferred anti-aphrodisiac reduces harassment of recently mated females
- 2000
-
In: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 267:1450, s. 1271-1275
-
Journal article (peer-reviewed)abstract
- Sexual selection theory predicts that the different selection pressures on males and females result in sexual conflict. However, in some instances males and females share a common interest which could lead to sexual cooperation. In the pierid butterfly Pieris napi the male and the recently mated female share a common interest in reducing female harassment by other males soon after mating. Here we show that P. napi males transfer an anti-aphrodisiac to the female at mating, methyl-salicylate (MeS), which is a volatile substance which mated females emit when courted and which makes males quickly abandon them. A C-13-labelling experiment demonstrated that only males synthesize MeS. The effect of this antiaphrodisiac is so strong that most males will refrain from mating with virgin females to whom MeS has been artificially applied. In P. napi, males also transfer nutrients to females at mating. This increases female fecundity and longevity and so females benefit from remating. Hence, sexual cooperation gradually turns to conflict. Future research is required to reveal which sex controls the gradual decrease in the MeS titre which is necessary for allowing mated females to regain attractiveness and remate.
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| 16. |
- Andersson, Linus, et al.
(author)
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A matter of time: Bateman's principles and mating success as count and duration across social strata in contemporary Finland
- 2023
-
In: Proceedings of the Royal Society of London. Biological Sciences. - 0962-8452 .- 1471-2954. ; 290:2002
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Journal article (other academic/artistic)abstract
- Bateman's principles heavily influence the understanding of human reproductive behaviour. Yet, few rigorous studies on Bateman's principles in contemporary industrialized populations exist. Most studies use small samples, exclude non-marital unions, and disregard recent insights on within-population heterogeneity in mating strategies. We assess mating success and reproductive success using population-wide Finnish register data on marital and non-marital cohabitations and fertility. We examine variability across social strata in the Bateman principles and analyse the mate count, the cumulated duration with a mate, and the association with reproductive success. Results support Bateman's first and second principles. Regarding Bateman's third principle, the number of mates is more positively associated with reproductive success for men than women, but this association is driven by ever having a mate. Having more than one mate is on average associated with lower reproductive success. However, for men in the lowest income quartile, having more than one mate positively predicts reproductive success. Longer union duration is associated with higher reproductive success, and more so for men. We note that sex differences in the relationship between mating success and reproductive success differ by social strata, and argue that mate duration may be an important component of mating success alongside mate count.
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| 17. |
- ANDERSSON, MS, et al.
(author)
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GLYCOSYLATED HEMOGLOBIN - A NEW MEASURE OF CONDITION IN BIRDS
- 1995
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In: PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES B-BIOLOGICAL SCIENCES. - : ROYAL SOC LONDON. - 0962-8452. ; 260:1359, s. 299-303
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Journal article (other academic/artistic)abstract
- The influence of condition on time of breeding and reproductive success has been discussed since Darwin first suggested a relation in 1871. We used a novel method to investigate the influence of condition on the timing of breeding and reproductive success
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| 18. |
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| 19. |
- Angeler, David
(author)
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Body size distributions signal a regime shift in a lake ecosystem
- 2016
-
In: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 283
-
Journal article (peer-reviewed)abstract
- Communities of organisms, from mammals to microorganisms, have discontinuous distributions of body size. This pattern of size structuring is a conservative trait of community organization and is a product of processes that occur at multiple spatial and temporal scales. In this study, we assessed whether body size patterns serve as an indicator of a threshold between alternative regimes. Over the past 7000 years, the biological communities of Foy Lake (Montana, USA) have undergone a major regime shift owing to climate change. We used a palaeoecological record of diatom communities to estimate diatom sizes, and then analysed the discontinuous distribution of organism sizes over time. We used Bayesian classification and regression tree models to determine that all time intervals exhibited aggregations of sizes separated by gaps in the distribution and found a significant change in diatom body size distributions approximately 150 years before the identified ecosystem regime shift. We suggest that discontinuity analysis is a useful addition to the suite of tools for the detection of early warning signals of regime shifts.
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| 20. |
- Anikin, Andrey, et al.
(author)
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Harsh is large : Nonlinear vocal phenomena lower voice pitch and exaggerate body size
- 2021
-
In: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 288:1954
-
Journal article (peer-reviewed)abstract
- A lion’s roar, a dog’s bark, an angry yell in a pub brawl: what do these voca-lizations have in common? They all sound harsh due to nonlinear vocal phenomena (NLP)—deviations from regular voice production, hypothesized to lower perceived voice pitch and thereby exaggerate the apparent bodysize of the vocalizer. To test this yet uncorroborated hypothesis, we synthesized human nonverbal vocalizations, such as roars, groans and screams, with and without NLP (amplitude modulation, subharmonics and chaos).We then measured their effects on nearly 700 listeners’ perceptions of three psychoacoustic (pitch, timbre, roughness) and three ecological (body size, for-midability, aggression) characteristics. In an explicit rating task, all NLP lowered perceived voice pitch, increased voice darkness and roughness, and caused vocalizers to sound larger, more formidable and more aggressive. Key results were replicated in an implicit associations test, suggesting that the‘harsh is large’ bias will arise in ecologically relevant confrontational contexts that involve a rapid, and largely implicit, evaluation of the opponent’s size. In sum, nonlinearities in human vocalizations can flexibly communicate both formidability and intention to attack, suggesting they are not a mere byproduct of loud vocalizing, but rather an informative acoustic signal wellsuited for intimidating potential opponents.
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| 21. |
- Aplin, Lucy M., et al.
(author)
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Individual-level personality influences social foraging and collective behaviour in wild birds
- 2014
-
In: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 281:1789, s. 20141016-
-
Journal article (peer-reviewed)abstract
- There is increasing evidence that animal groups can maintain coordinated behaviour and make collective decisions based on simple interaction rules. Effective collective action may be further facilitated by individual variation within groups, particularly through leader-follower polymorphisms. Recent studies have suggested that individual-level personality traits influence the degree to which individuals use social information, are attracted to conspecifics, or act as leaders/followers. However, evidence is equivocal and largely limited to laboratory studies. We use an automated data-collection system to conduct an experiment testing the relationship between personality and collective decision-making in the wild. First, we report that foraging flocks of great tits (Parus major) show strikingly synchronous behaviour. A predictive model of collective decision-making replicates patterns well, suggesting simple interaction rules are sufficient to explain the observed social behaviour. Second, within groups, individuals with more reactive personalities behave more collectively, moving to within-flock areas of higher density. By contrast, proactive individuals tend to move to and feed at spatial periphery of flocks. Finally, comparing alternative simulations of flocking with empirical data, we demonstrate that variation in personality promotes within-patch movement while maintaining group cohesion. Our results illustrate the importance of incorporating individual variability in models of social behaviour.
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| 22. |
- Arlt, D, et al.
(author)
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Observation of a ZZW female in a natural population: implications for avian sex determination
- 2004
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In: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 271:S4, s. 249-251
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Journal article (peer-reviewed)abstract
- Avian sex determination is chromosomal; however, the underlying mechanisms are not yet understood. There is no conclusive evidence for either of two proposed mechanisms: a dominant genetic switch or a dosage mechanism. No dominant sex-determining gene on the female-specific W chromosome has been found. Birds lack inactivation of one of the Z chromosomes in males, but seem to compensate for a double dose of Z-linked genes by other mechanisms. Recent studies showing female-specific expression of two genes may support an active role of the W chromosome. To resolve the question of avian sex determination the investigation of birds with a 2A: ZZW or 2A: Z0 genotype would be decisive. Here, we report the case of an apparent 2A: ZZW great reed warbler (Acrocephalus arundinaceus) female breeding in a natural population, which was detected using Z-linked microsatellites. Our data strongly suggest a role of W-linked genes in avian sex determination.
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| 23. |
- Arnqvist, Göran, Professor, 1961-, et al.
(author)
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Direct and indirect effects of male genital elaboration in female seed beetles
- 2021
-
In: Proceedings of the Royal Society of London. Biological Sciences. - London : Royal Society. - 0962-8452 .- 1471-2954. ; 288:1954
-
Journal article (peer-reviewed)abstract
- Our understanding of coevolution between male genitalia and female traits remains incomplete. This is perhaps especially true for genital traits that cause internal injuries in females, such as the spiny genitalia of seed beetles where males with relatively long spines enjoy a high relative fertilization success. We report on a new set of experiments, based on extant selection lines, aimed at assessing the effects of long male spines on females in Callosobruchus maculatus . We first draw on an earlier study using microscale laser surgery, and demonstrate that genital spines have a direct negative (sexually antagonistic) effect on female fecundity. We then ask whether artificial selection for long versus short spines resulted in direct or indirect effects on female lifetime offspring production. Reference females mating with males from long-spine lines had higher offspring production, presumably due to an elevated allocation in males to those ejaculate components that are beneficial to females. Remarkably, selection for long male genital spines also resulted in an evolutionary increase in female offspring production as a correlated response. Our findings thus suggest that female traits that affect their response to male spines are both under direct selection to minimize harm but are also under indirect selection (a good genes effect), consistent with the evolution of mating and fertilization biases being affected by several simultaneous processes.
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| 24. |
- Arnqvist, Göran, et al.
(author)
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Genome size correlates with reproductive fitness in seed beetles
- 2015
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In: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 282:1815
-
Journal article (peer-reviewed)abstract
- The ultimate cause of genome size (GS) evolution in eukaryotes remains a major and unresolved puzzle in evolutionary biology. Large-scale comparative studies have failed to find consistent correlations between GS and organismal properties, resulting in the 'C-value paradox'. Current hypotheses for the evolution of GS are based either on the balance between mutational events and drift or on natural selection acting upon standing genetic variation in GS. It is, however, currently very difficult to evaluate the role of selection because within-species studies that relate variation in life-history traits to variation in GS are very rare. Here, we report phylogenetic comparative analyses of GS evolution in seed beetles at two distinct taxonomic scales, which combines replicated estimation of GS with experimental assays of life-history traits and reproductive fitness. GS showed rapid and bidirectional evolution across species, but did not show correlated evolution with any of several indices of the relative importance of genetic drift. Within a single species, GS varied by 4-5% across populations and showed positive correlated evolution with independent estimates of male and female reproductive fitness. Collectively, the phylogenetic pattern of GS diversification across and within species in conjunction with the pattern of correlated evolution between GS and fitness provide novel support for the tenet that natural selection plays a key role in shaping GS evolution.
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| 25. |
- Arnqvist, Göran, et al.
(author)
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Sexual conflict and the gender load : correlated evolution between population fitness and sexual dimorphism in seed beetles
- 2010
-
In: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 277:1686, s. 1345-1352
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Journal article (peer-reviewed)abstract
- Although males and females share much of the same genome, selection is often distinct in the two sexes. Sexually antagonistic loci will in theory cause a gender load in populations, because sex-specific selection on a given trait in one sex will compromise the adaptive evolution of the same trait in the other sex. However, it is currently not clear whether such intralocus sexual conflict (ISC) represents a transient evolutionary state, where conflict is rapidly resolved by the evolution of sexual dimorphism (SD), or whether it is a more chronic impediment to adaptation. All else being equal, ISC should manifest itself as correlated evolution between population fitness and SD in traits expressed in both sexes. However, comparative tests of this prediction are problematic and have been unfeasible. Here, we assess the effects of ISC by comparing fitness and SD across distinct laboratory populations of seed beetles that should be well adapted to a shared environment. We show that SD in juvenile development time, a key life-history trait with a history of sexually antagonistic selection in this model system, is positively related to fitness. This effect is due to a correlated evolution between population fitness and development time that is positive in females but negative in males. Loosening the genetic bind between the sexes has evidently allowed the sexes to approach their distinct adaptive peaks.
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