The definition of sexual selection Shuker, David M; Kvarnemo, Charlotta
Behavioral ecology,
09/2021, Letnik:
32, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Abstract
Sexual selection is a key component of evolutionary biology. However, from the very formulation of sexual selection by Darwin, the nature and extent of sexual selection have been ...controversial. Recently, such controversy has led back to the fundamental question of just what sexual selection is. This has included how we incorporate female-female reproductive competition into sexual or natural selection. In this review, we do four things. First, we examine what we want a definition to do. Second, we define sexual selection: sexual selection is any selection that arises from fitness differences associated with nonrandom success in the competition for access to gametes for fertilization. An important outcome of this is that as mates often also offer access to resources, when those resources are the targets of the competition, rather than their gametes, the process should be considered natural rather than sexual selection. We believe this definition encapsulates both much of Darwin’s original thinking about sexual selection, and much of how contemporary biologists use the concept of sexual selection. Third, we address alternative definitions, focusing in some detail on the role of female reproductive competition. Fourth, we challenge our definition with a number of scenarios, for instance where natural and sexual selection may align (as in some forms of endurance rivalry), or where differential allocation means teasing apart how fecundity and access to gametes influence fitness. In conclusion, we emphasize that whilst the ecological realities of sexual selection are likely to be complex, the definition of sexual selection is rather simple.
Sexual selection is a crucial component of evolutionary biology yet debate over what forms of selection do or don’t comprise sexual selection have re-surfaced over the last couple of decades. Here we provide and justify a definition of sexual selection, that is focused on competition for access to gametes, and challenge that definition with ecologically complex scenarios. We hope this will allow the field to move forward, building on a firm conceptual basis.
Quantifying the shape and strength of mating preferences is a vital component of the study of sexual selection and reproductive isolation, but the influence of experimental design on these estimates ...is unclear. Mating preferences may be tested using either no-choice or choice designs, and these tests may result in different estimates of preference strength. However, previous studies testing for this difference have given mixed results. To quantify the difference in the strength of mating preferences obtained using the 2 designs, we performed a meta-analysis of 38 studies on 40 species in which both experimental designs were used to test for preferences in a single species/trait/sex combination. We found that mating preferences were significantly stronger when tested using a choice design compared with a no-choice design. We suggest that this difference is due to the increased cost of rejecting partners in no-choice tests; if individuals perceive they are unlikely to remate in a no-choice situation they will be more likely to mate randomly. Importantly the use of choice tests in species in which mates are primarily encountered sequentially in the wild may lead to mating preferences being significantly overestimated. Furthermore, this pattern was seen for female mate choice but not for male mate choice, and for intraspecific choice but not for interspecies or interpopulation mate discrimination. Our study thus highlights the fact that the strength of mating preferences, and thus sexual selection, can vary significantly between experimental designs and across different social and ecological contexts.Lay Summary Mating preferences in animals are stronger when individuals have more than one option to choose from. We performed a meta-analysis of studies in which mating preferences were tested using 2 experimental designs: no-choice tests and choice tests. This difference in preferences between designs was only seen for female, intraspecific mate choice. Individuals may be less choosy in no-choice tests because the likelihood of encountering another mate is perceived to be lower than in choice tests.
Coevolutionary interactions, such as those between host and parasite, predator and prey, or plant and pollinator, evolve subject to the genes of both interactors. It is clear, for example, that the ...evolution of pollination strategies can only be understood with knowledge of both the pollinator and the pollinated. Studies of the evolution of virulence, the reduction in host fitness due to infection, have nonetheless tended to focus on parasite evolution. Host-centric approaches have also been proposed--for example, under the rubric of "tolerance", the ability of hosts to minimize virulence without necessarily minimizing parasite density. Within the tolerance framework, however, there is room for more comprehensive measures of host fitness traits, and for fuller consideration of the consequences of coevolution. For example, the evolution of tolerance can result in changed selection on parasite populations, which should provoke parasite evolution despite the fact that tolerance is not directly antagonistic to parasite fitness. As a result, consideration of the potential for parasite counter-adaptation to host tolerance--whether evolved or medially manipulated--is essential to the emergence of a cohesive theory of biotic partnerships and robust disease control strategies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Many organisms monitor the annual change in day length and use this information for the timing of their seasonal response. However, the molecular mechanisms underlying photoperiodic timing are ...largely unknown. The wasp Nasonia vitripennis is an emerging model organism that exhibits a strong photoperiodic response: Short autumnal days experienced by females lead to the induction of developmental arrest (diapause) in their progeny, allowing winter survival of the larvae. How female Nasonia control the developmental trajectory of their offspring is unclear. Here, we took advantage of the recent discovery that DNA methylation is pervasive in Nasonia and tested its role in photoperiodism. We used reduced representation bisulfite sequencing (RRBS) to profile DNA methylation in adult female wasps subjected to different photoperiods and identified substantial differential methylation at the single base level. We also show that knocking down DNA methyltransferase 1a (Dnmt1a), Dnmt3, or blocking DNA methylation pharmacologically, largely disrupts the photoperiodic diapause response of the wasps. To our knowledge, this is the first example for a role of DNA methylation in insect photoperiodic timing.
Polyandry, or multiple mating by females with different males, is commonplace. One explanation is that females engage in convenience polyandry, mating multiple times to reduce the costs of sexual ...harassment. Although the logic underlying convenience polyandry is clear, and harassment often seems to influence mating outcomes, it has not been subjected to as thorough theoretical or empirical attention as other explanations for polyandry. We re-examine here convenience polyandry in the light of new studies demonstrating previously unconsidered benefits of polyandry. We suggest that true convenience polyandry is likely to be a fleeting phenomenon, even though it can profoundly shape mating-system evolution via potential feedback loops between resistance to males and the costs and benefits of mating.
Convenience polyandry can occur when resistance is more costly than mating.
When females do not benefit from polyandry it is sometimes suggested as being convenient.
Convenience polyandry is rarely explicitly tested.
New studies show cryptic benefits to females that negate convenience polyandry.
Convenience polyandry may be a fleeting phenomenon that has the potential to shape mating system evolution.
We provide a framework in which to test whether or not polyandry is convenient.
Reproductive interference in insects SHUKER, DAVID M.; BURDFIELD‐STEEL, EMILY R.
Ecological entomology,
August 2017, 2017-08-00, 20170801, Letnik:
42, Številka:
S1
Journal Article
Recenzirano
Odprti dostop
1. Reproductive interference occurs when members of different species engage in reproductive interactions, leading to a fitness cost to one or both actors.
2. These interactions can arise through ...signal interference (‘signal‐jamming’), disrupted mate searching, heterospecific rivalry, mate choice errors, or misplaced courtship, mating attempts or copulation.
3. We present a definition of reproductive interference (RI) and discuss the extent to which a failure of species discrimination is central to a definition of RI.
4. The possible mechanisms of RI are reviewed, using a range of insect examples.
5. Some of the causes and consequences of RI are discussed, focusing in particular on mating systems and mating system evolution.
6. We conclude by considering future ways forward, highlighting the opportunities for new theory and tests of the old theory presented by reproductive interference.
Reproductive interference (RI) can arise through processes such as:
signal jamming;
mis‐directed courtship or copulation;
mis‐directed intrasexualrivalry.
We focus on RI and mating system evolution.
We stress that RI may often involves a failure of species discrimination, but this need not always be the case.
Niche construction refers to the activities of organisms that bring about changes in their environments, many of which are evolutionarily and ecologically consequential. Advocates of niche ...construction theory (NCT) believe that standard evolutionary theory fails to recognize the full importance of niche construction, and consequently propose a novel view of evolution, in which niche construction and its legacy over time (ecological inheritance) are described as evolutionary processes, equivalent in importance to natural selection. Here, we subject NCT to critical evaluation, in the form of a collaboration between one prominent advocate of NCT, and a team of skeptics. We discuss whether niche construction is an evolutionary process, whether NCT obscures or clarifies how natural selection leads to organismal adaptation, and whether niche construction and natural selection are of equivalent explanatory importance. We also consider whether the literature that promotes NCT overstates the significance of niche construction, whether it is internally coherent, and whether it accurately portrays standard evolutionary theory. Our disagreements reflect a wider dispute within evolutionary theory over whether the neo-Darwinian synthesis is in need of reformulation, as well as different usages of some key terms (e.g., evolutionary process).
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