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1.
    
Gametic asymmetry implies that females invest more per gamete than males do and thus sperm is considered to be a relatively cheap resource. However, contrary to this classic view, sperm has been shown to be frequently in short supply; hence, selection favouring females that mate for fertility benefits should occur. For this reason, we determined whether males signalling fertility are preferred by female newts of the species Triturus alpestris . We performed paired female–male trials using unmated and previously inseminated females to determine potential criteria for female interest in a courting male, to establish what factors lead to successful mating and to assess the importance of female choice for direct and indirect benefits. We found that female interest in any potential mate and mating success decreased once mating had occurred. Furthermore, we detected an increase in spermatophore deposition rate and rapid spermatophore transfer in encounters that resulted in a successful mating. The results obtained indicate that female alpine newts are attracted to males showing signs of relatively high fertility and that females exhibit a decreased propensity to mate once initial sperm reserves have been acquired. Our results support the theory of initial female choice for fertility benefits.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 483–491.  相似文献   

2.
    
The time a female spends in front of a male is a commonly assumed but rarely tested measure of female mate preference in mate choice experiments. I investigated whether the mate preference in zebra finch females Taeniopygia guttata castanotis measured as the number of solicitations directed towards a male was related to the time females spent with that male. In a binary choice situation within an aviary, females were allowed to fly freely and visit two individually caged males over a whole day. I measured the females' solicitation displays as the number of tail quivering and/or presentations of nesting material. I also measured the time the females spent in front of each male. Females that solicited did so exclusively to one of the two males and when they did they spent almost twice as much time with that male than with the other. The time these females spent in front of a male correlated positively with the number of solicitation displays directed to that male. The study shows the first experimental link between mate preference measured by courtship displays and preference measured as the time a female spends with a male. Hence, time spent with a male, the most common measure of female mate preference in zebra finches choice experiments is a good indicator of female mate preference.  相似文献   

3.
  总被引:2,自引:0,他引:2  
Filial cannibalism (the consumption of one's own viable offspring) is common among fish with paternal care. In this study, I use a computer simulation to study simultaneous evolution of male filial cannibalism and female mate choice. Under certain conditions, selection on parental males favors filial cannibalism. When filial cannibalism increases a male's probability to raise the current brood successfully, filial cannibalism also benefits the female. However, when egg eating is a male investment into future reproduction, a conflict between female and male interests emerges. Here I investigate how female discrimination against filial cannibals affects evolution of filial cannibalism and how different female choice criteria perform against filial cannibalism. The introduction of discriminating females makes the fixation of filial cannibalism less likely. I introduced three different female choice criteria: (1) females who could discern a male's genotype, that is, whether the male was going to eat eggs as an investment in future reproductive events; (2) energy-choosing females that preferred to mate with males who had enough energy reserves to live through the current brood cycle without consuming eggs; and (3) females that preferred to mate with already mated males, that is, males with eggs in their nest. Genotype choice never coexisted with filial cannibals at fixation and filial cannibals were unable to invade a population with genotype-choosing females. Energy choice was successful only when males had high energy reserves and were less dependent on filial cannibalism as an alternative energy source. The egg choosers frequently coexisted with the cannibals at fixation. When the female strategies were entered simultaneously, the most frequent outcome for low mate sampling costs was that both the cannibals and the egg choice was fixed and all other strategies went extinct. These results suggest that sexual conflicts may not always evolve toward a resolution of the conflict, but sometimes the stable state retains the conflict. In the present case, this was because the egg-preference strategy had a higher fitness than the other female strategies. The outcome of this simulation is similar to empirical findings. In fish with paternal care, male filial cannibalism and female preference for mates with eggs commonly co-occur.  相似文献   

4.
    
Mating displays often contain multiple signals. Different combinations of these signals may be equally successful at attracting a mate, as environment and signal combination may influence relative signal weighting by choosy individuals. This variation in signal weighting among choosy individuals may facilitate the maintenance of polymorphic displays and signalling behaviour. One group of animals known for their polymorphic patterning are Batesian mimetic butterflies, where the interaction of sexual selection and predation pressures is hypothesized to influence the maintenance of polymorphic wing patterning and behaviour. Males in the female‐limited polymorphic Batesian mimetic butterfly Papilio polytes use female wing pattern and female activity levels when determining whom to court. They court stationary females with mimetic wing patterns more often than stationary females with non‐mimetic, male‐like wing patterns and active females more often than inactive females. It is unclear whether females modify their behaviour to increase (or decrease) their likelihood of receiving male courtship, or whether non‐mimetic females spend more time in cryptic environments than mimetic females, to compensate for their lack of mimicry‐driven predation protection (at the cost of decreased visibility to males). In addition, relative signal weighting of female wing pattern and activity to male mate selection is unknown. To address these questions, we conducted a series of observational studies of a polymorphic P. polytes population in a large butterfly enclosure. We found that males exclusively courted active females, irrespective of female wing pattern. However, males did court active non‐mimetic females significantly more often than expected given their relative abundance in the population. Females exhibited similar activity levels, and selected similar resting environments, irrespective of wing pattern. Our results suggest that male preference for non‐mimetic females may play an active role in the maintenance of the non‐mimetic female form in natural populations, where males are likely to be in the presence of active, as well as inactive, mimetic and non‐mimetic females.  相似文献   

5.
    
In promiscuous species with sperm storage, males are expected to show a preference for mating with virgin and young females to reduce the risk of sperm competition. In the simultaneous hermaphrodite land snail Arianta arbustorum, sperm production precedes egg production by 2–4 weeks, resulting in a short period of protandric hermaphroditism before shell growth is completed. In natural populations, copulating pairs involving individuals which have not yet completed shell growth (virgins) have been observed. We ran a series of mate-choice experiments to examine whether virgin and nonvirgin (experienced) individuals of A. arbustorum discriminate between virgin and nonvirgin mating partners. We also assessed the number of sperm delivered to partners with different mating status. Neither virgin nor nonvirgin snails showed any preference for mating with a virgin partner. In all test situations mating was random and the number of sperm delivered was not adjusted to the mating status of the partner. Mating success was mainly determined by the activity of the individual. The random mating pattern does not imply random fertilization of eggs because the presence of a sperm-digesting organ and the morphology of the sperm storage organ allow a selective storage and use of sperm in A. arbustorum.  相似文献   

6.
    
Females of many species are frequently courted by promiscuous males of their own and other closely related species. Such mating interactions may impose strong selection on female mating preferences to favor trait values in conspecific males that allow females to discriminate them from their heterospecific rivals. We explore the consequences of such selection in models of the evolution of female mating preferences when females must interact with heterospecific males from which they are completely postreproductively isolated. Specifically, we allow the values of both the most preferred male trait and the tolerance of females for males that deviate from this most preferred trait to evolve. Also, we consider situations in which females base their mating decisions on multiple male traits and must interact with males of multiple species. Females will rapidly differentiate in preference when they sometimes mistake heterospecific males for suitable mates, and the differentiation of female preference will select for conspecific male traits to differentiate as well. In most circumstances, this differentiation continues indefinitely, but slows substantially once females are differentiated enough to make mistakes rare. Populations of females with broader preference functions (i.e., broader tolerance for males with trait values that deviate from females' most preferred values) will evolve further to differentiate if the shape of the function cannot evolve. Also, the magnitude of separation that evolves is larger and achieved faster when conspecific males have lower relative abundance. The direction of differentiation is also very sensitive to initial conditions if females base their mate choices on multiple male traits. We discuss how these selection pressures on female mate choice may lead to speciation by generating differentiation among populations of a progenitor species that experiences different assemblages of heterospecifics. Opportunities for differentiation increase as the number of traits involved in mate choice increase and as the number of species involved increases. We suggest that this mode of speciation may have been particularly prevalent in response to the cycles of climatic change throughout the Quaternary that forced the assembly and disassembly of entire communities on a continentwide basis.  相似文献   

7.
    
Abstract.  1. Two types of Genji firefly, Luciola cruciata , have been recognised on the basis of the inter-flash interval.
2. The fast-flash and slow-flash type fireflies, distributed in the western and eastern parts of Japan, exhibit a 2- and 4-s interval of bioluminescence flash, respectively. In addition, an intermediate-flash type is found on the boundary between these two regions.
3. The differences in the responses of the males of four field populations to different intervals of artificial flashes were examined.
4. The results revealed that in the Aomori and Sendai populations (slow-flash type), a significantly larger number of males approached the 4- and 5-s flash intervals than approached the 2- and 3-s intervals of artificial flashes. On the other hand, in the Ohtsu population (fast-flash type), a significantly larger number of males approached the 2- and 3-s flash intervals than the 4- and 5-s intervals of artificial flashes. The Inuyama population (intermediate-flash type) did not show any particular preferences to flash intervals.
5. This study shows that in firefly populations, geographic variation in flash pattern can cause some degree of pre-mating isolation between populations.  相似文献   

8.
9.
    
The evolution of mate preferences can be critical for the evolution of reproductive isolation and speciation. Heterospecific interference may carry substantial fitness costs and result in preferences where females are most responsive to the mean conspecific trait with low response to traits that differ from this value. However, when male traits are unbounded by heterospecifics, there may not be selection against females that respond to extreme trait values in the unbounded direction. To test how heterospecifics affected the shape of female response functions, I presented female Oecanthus tree crickets with synthetic calls representing a range of male calls, then measured female phonotaxis to construct response functions. The species with the fastest pulse rates in the community consistently responded to pulse rates faster than those produced by their males, whereas in the intermediate and slowest pulse rate species there was no significant difference between the male trait and the female response. This work suggests that species with the most extreme signal in the community respond to a greater range of signals, potentially resulting in a higher probability of hybridization during secondary contact, and revealing interactions between mate recognition and other aspects of sexual selection.  相似文献   

10.
    
Why are there so few small secondary sexual characters? Theoretical models predict that sexual selection should lead to reduction as often as exaggeration, and yet we mainly associate secondary sexual ornaments with exaggerated features such as the peacock's tail. We review the literature on mate choice experiments for evidence of reduced sexual traits. This shows that reduced ornamentation is effectively impossible in certain types of ornamental traits (behavioral, pheromonal, or color‐based traits, and morphological ornaments for which the natural selection optimum is no trait), but that there are many examples of morphological traits that would permit reduction. Yet small sexual traits are very rarely seen. We analyze a simple mathematical model of Fisher's runaway process (the null model for sexual selection). Our analysis shows that the imbalance cannot be wholly explained by larger ornaments being less costly than smaller ornaments, nor by preferences for larger ornaments being less costly than preferences for smaller ornaments. Instead, we suggest that asymmetry in signaling efficacy limits runaway to trait exaggeration.  相似文献   

11.
    
Why are traits that function as secondary sexual ornaments generally exaggerated in size compared to the naturally selected optimum, and not reduced? Because they deviate from the naturally selected optimum, traits that are reduced in size will handicap their bearer, and could thus provide an honest signal of quality to a potential mate. Thus if secondary sexual ornaments evolve via the handicap process, current theory suggests that reduced ornamentation should be as frequent as exaggerated ornamentation, but this is not the case. To try to explain this discrepancy, we analyze a simple model of the handicap process. Our analysis shows that asymmetries in costs of preference or ornament with regard to exaggeration and reduction cannot fully explain the imbalance. Rather, the bias toward exaggeration can be best explained if either the signaling efficacy or the condition dependence of a trait increases with size. Under these circumstances, evolution always leads to more extreme exaggeration than reduction: although the two should occur just as frequently, exaggerated secondary sexual ornaments are likely to be further removed from the naturally selected optimum than reduced ornaments.  相似文献   

12.
  总被引:1,自引:0,他引:1  
Fluctuating asymmetry (FA) has been suggested as a measure of the sensitivity of development to a wide array of genetic and environmental stresses. It has been also suggested that antlers in red deer could be important during social and rutting displays. We used antler measurements of 51 males that were measured over subsequent seasons, from 3–8 years of age, and analysed three antler traits: antler weight, length, and the number of antler tines (antler size). We calculated absolute and relative FA. All three size traits were highly significantly intercorrelated. By contrast to this, the FA of the three traits, did not show such relationships. With increasing age, antler size and FA also increased. When testing the repeatability of FA and antler size, there was a principal difference in the pattern between FA and antler size, with the latter being much more consistent than the former. This suggests that antler size, not FA, may be a good predictor of the bearer's quality in mate selection. This fits well with the good-genes hypothesis that the development of extravagant secondary sexual characters can be an honest advertisement of heritable male quality.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 215–226.  相似文献   

13.
14.
  总被引:1,自引:0,他引:1  
Red deer hinds play a significant role in selecting stags for mating. We tested the hypotheses that in red deer ( Cervus elaphus ) the probability of becoming a harem holder (and hence achieving reproductive success) occurs in stags bearing larger, branched antlers and showing low fluctuating asymmetry (FA). Eleven antler characteristics were measured; absolute and relative FA were calculated on 51 cast antler sets from 19 individually recognized stags. Probability of becoming a harem holder (PBHH) was originally analysed separately, i.e. for antler size and FA of each antler characteristic and calculated factors for both antler size and FA. If analysed separately, large antler size and low relative but high absolute FA increased PBHH. When we combined antler size and FA of antler characteristics in one model using antler size and FA factors, however, PBHH and achieving reproductive success were mainly dependent on increasing antler size and enhanced antler branching rather than on FA. We conclude that in contrast to antler size, FA is unlikely to play any significant role in sexual selection as an indicator of individual quality.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 59–68.  相似文献   

15.
Females often prefer to mate with high quality males, and one aspect of quality is physical performance. Although a preference for physically fitter males is therefore predicted, the relationship between attractiveness and performance has rarely been quantified. Here, I test for such a relationship in humans and ask whether variation in (endurance) performance is associated with variation in facial attractiveness within elite professional cyclists that finished the 2012 Tour de France. I show that riders that performed better were more attractive, and that this preference was strongest in women not using a hormonal contraceptive. Thereby, I show that, within this preselected but relatively homogeneous sample of the male population, facial attractiveness signals endurance performance. Provided that there is a relationship between performance-mediated attractiveness and reproductive success, this suggests that human endurance capacity has been subject to sexual selection in our evolutionary past.  相似文献   

16.
    
A two-locus diploid model of sexual selection is presented in which the two loci govern, respectively, a trait limited in expression in one sex (generally male) and the mating preferences of the other sex (generally female). The viability of a male depends on its genotype at the trait locus. In contrast, all females are equally viable and all individuals are equally fertile with respect to the two loci. Near fixation at both loci, evolution at the mating locus is neutral and hence a new mating preference allele will increase only through random genetic drift or through a correlated response to the increase of a new advantageous trait allele. If, however, a polymorphism is already maintained at the trait locus through overdominance in fitness then the increase of a rare preference allele depends only on the recombination rate between the loci and not on the new preference scheme.  相似文献   

17.
    
Variation in pigmentation traits is an effective window to evolutionary processes due to their importance for survival and reproduction. In particular, one of the leading hypotheses for the maintenance of conspicuous pigmentation in natural populations is its signaling function in mate choice. Here, we demonstrate the occurrence of melanism in poeciliid fishes of the genus Poecilia that inhabits toxic, hydrogen sulfide springs in southern Mexico and the absence of melanism from closely related populations in reference habitats lacking hydrogen sulfide. Assays of female mate preference in both habitat types were used to examine whether divergence in female preference for melanism contributes to its maintenance in hydrogen sulfide springs. We found significant variation in female preferences for melanistic males. Specifically, melanistic females from the toxic spring exhibited a significant preference for melanistic males, while non‐melanistic females from the same population exhibited no preference. Females from the non‐sulfidic reference population discriminated strongly against melanistic males. Preferences of melanistic females appear to be a significant force in the maintenance of melanism in sulfidic habitats and suggest a change in preference as the divergence from non‐sulfidic ancestors. Potential polymorphism in preference within the hydrogen sulfide spring indicates that preference for melanistic males may not be environmentally controlled. Thus, a change in preference following divergence can promote the maintenance of variation in pigmentation within populations and between divergent habitats.  相似文献   

18.
    
Sexual selection is widely hypothesized to facilitate the evolution of reproductive isolation through divergence in sexual traits and sexual trait preferences among populations. However, direct evidence of divergent sexual selection causing intraspecific trait divergence remains limited. Using the wolf spider Schizocosa crassipes, we characterized patterns of female mate choice within and among geographic locations and related those patterns to geographic variation in male display traits to test whether divergent sexual selection caused by mate choice explains intraspecific trait variation. We found evidence of phenotypic selection on male behavior arising from female mate choice, but no evidence that selection varied among locations. Only those suites of morphological and behavioral traits that did not influence mate choice varied geographically. These results are inconsistent with ongoing divergent sexual selection underlying the observed intraspecific divergence in male display traits. These findings align with theory on the potentially restrictive conditions under which divergent sexual selection may persist, and suggest that long‐term studies capable of detecting periodic or transient divergent sexual selection will be critical to rigorously assess the relative importance of divergent sexual selection in intraspecific trait divergence.  相似文献   

19.
20.
    
The phenotype‐linked fertility hypothesis proposes that male fertility is advertised via phenotypic signals, explaining female preference for highly sexually ornamented males. An alternative view is that highly attractive males constrain their ejaculate allocation per mating so as to participate in a greater number of matings. Males are also expected to bias their ejaculate allocation to the most fecund females. We test these hypotheses in the African stalk‐eyed fly, Diasemopsis meigenii. We ask how male ejaculate allocation strategy is influenced by male eyespan and female size. Despite large eyespan males having larger internal reproductive organs, we found no association between male eyespan and spermatophore size or sperm number, lending no support to the phenotype‐linked fertility hypothesis. However, males mated for longer and transferred more sperm to large females. As female size was positively correlated with fecundity, this suggests that males gain a selective advantage by investing more in large females. Given these findings, we consider how female mate preference for large male eyespan can be adaptive despite the lack of obvious direct benefits.  相似文献   

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