scholarly journals Why is mutual mate choice not the norm? Operational sex ratios, sex roles and the evolution of sexually dimorphic and monomorphic signalling

2002 ◽  
Vol 357 (1419) ◽  
pp. 319-330 ◽  
Author(s):  
H. Kokko ◽  
R. A. Johnstone
Keyword(s):  
Mate Choice ◽  
Parental Care ◽  
Parental Investment ◽  
Sex Roles ◽  
Mating Strategies ◽  
Operational Sex Ratio ◽  
Encounter Rate ◽  
Theoretic Model ◽  
Biparental Care ◽  
Mutual Mate Choice

Biases in the operational sex ratio (OSR) are seen as the fundamental reason behind differential competition for mates in the two sexes, and as a strong determinant behind differences in choosiness. This view has been challenged by Kokko and Monaghan, who argue that sex–specific parental investment, mortalities, mate–encounter rates and quality variation determine the mating system in a way that is not reducible to the OSR. We develop a game–theoretic model of choosiness, signalling and parental care, to examine (i) whether the results of Kokko and Monaghan remain robust when its simplifying assumptions are relaxed, (ii) how parental care coevolves with mating strategies and the OSR and (iii) why mutual mate choice is observed relatively rarely even when both sexes vary in quality. We find qualitative agreement with the simpler approach: parental investment is the primary determinant of sex roles instead of the OSR, and factors promoting choosiness are high species–specific mate–encounter rate, high sex–specific mate–encounter rate, high cost of breeding (parental investment), low cost of mate searching and highly variable quality of the opposite sex. The coevolution of parental care and mating strategies hinders mutual mate choice if one parent can compensate for reduced care by the other, but promotes it if offspring survival depends greatly on biparental care. We argue that the relative rarity of mutual mate choice is not due to biases in the OSR. Instead, we describe processes by which sexual strategies tend to diverge. This divergence is prevented, and mutual mate choice maintained, if synergistic benefits of biparental care render parental investment both high and not too different in the two sexes.

Sex Roles and Mutual Mate Choice Matter during Mate Sampling

2012 ◽  
Vol 179 (6) ◽  
pp. 741-755 ◽  
Author(s):  
Lise Cats Myhre ◽  
Karen de Jong ◽  
Elisabet Forsgren ◽  
Trond Amundsen
Keyword(s):  
Mate Choice ◽  
Sex Roles ◽  
Mutual Mate Choice ◽  
Mate Sampling

Mating system, mate choice and parental care in a bark beetle

2017 ◽  
Vol 107 (5) ◽  
pp. 611-619 ◽  
Author(s):  
O. Baruch ◽  
Z. Mendel ◽  
I. Scharf ◽  
A. R Harari
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Mate Choice ◽  
Parental Care ◽  
Mating System ◽  
Assortative Mating ◽  
Bark Beetle ◽  
Biparental Care ◽  
Male Body ◽  
Male Body Size

AbstractThe cypress bark beetle,Phloeosinus armatus, is a common element of the dying cypress tree system in East-Mediterranean countries. Adult beetles congregate for breeding on this ephemeral resource. We studied three traits that characterize this beetle's sexual behavior and linked them to its reproductive success: mating system, mate choice, and parental care. We found that the females are the ‘pioneering sex’, excavating the mating chamber. The average female is slightly larger than the male, and female and male body size is correlated, demonstrating size-assortative mating. The time it takes for a male to enter the mating chamber is positively correlated with female size and negatively correlated with its own size, which is perhaps responsible for this assortative mating. Males remain in the gallery during the period of oviposition, gradually leaving soon after the eggs hatch. The number of eggs laid and tunnel length are positively correlated with male body size. Finally, in the presence of both parents, more eggs are laid than when the female alone is present, demonstrating the important contribution of biparental care for reproductive success. We suggest that the interaction between a monogamous mating system, assortative mating, and biparental care contributes to reproductive success.

scholarly journals Lonely hearts or sex in the city? Density-dependent effects in mating systems

2006 ◽  
Vol 361 (1466) ◽  
pp. 319-334 ◽  
Author(s):  
Hanna Kokko ◽  
Daniel J Rankin
Keyword(s):  
Sexual Selection ◽  
Mate Choice ◽  
Parental Care ◽  
Mating Systems ◽  
Sex Role ◽  
Mate Guarding ◽  
Mating Strategies ◽  
Male Mating ◽  
Density Dependent ◽  
Basic Ideas

Two very basic ideas in sexual selection are heavily influenced by numbers of potential mates: the evolution of anisogamy, leading to sex role differentiation, and the frequency dependence of reproductive success that tends to equalize primary sex ratios. However, being explicit about the numbers of potential mates is not typical to most evolutionary theory of sexual selection. Here, we argue that this may prevent us from finding the appropriate ecological equilibria that determine the evolutionary endpoints of selection. We review both theoretical and empirical advances on how population density may influence aspects of mating systems such as intrasexual competition, female choice or resistance, and parental care. Density can have strong effects on selective pressures, whether or not there is phenotypic plasticity in individual strategies with respect to density. Mating skew may either increase or decrease with density, which may be aided or counteracted by changes in female behaviour. Switchpoints between alternative mating strategies can be density dependent, and mate encounter rates may influence mate choice (including mutual mate choice), multiple mating, female resistance to male mating attempts, mate searching, mate guarding, parental care, and the probability of divorce. Considering density-dependent selection may be essential for understanding how populations can persist at all despite sexual conflict, but simple models seem to fail to predict the diversity of observed responses in nature. This highlights the importance of considering the interaction between mating systems and population dynamics, and we strongly encourage further work in this area.

scholarly journals Sex roles and the evolution of parental care specialization

2019 ◽  
Vol 286 (1909) ◽  
pp. 20191312 ◽  
Author(s):  
Jonathan M. Henshaw ◽  
Lutz Fromhage ◽  
Adam G. Jones
Keyword(s):  
Parental Care ◽  
Parental Investment ◽  
Sex Roles ◽  
Sex Role ◽  
Relative Size ◽  
Female Competition ◽  
Male Mating ◽  
Recent Theory ◽  
Mating Competition ◽  
Uniparental Care

Males and females are defined by the relative size of their gametes (anisogamy), but secondary sexual dimorphism in fertilization, parental investment and mating competition is widespread and often remarkably stable over evolutionary timescales. Recent theory has clarified the causal connections between anisogamy and the most prevalent differences between the sexes, but deviations from these patterns remain poorly understood. Here, we study how sex differences in parental investment and mating competition coevolve with parental care specialization. Parental investment often consists of two or more distinct activities (e.g. provisioning and defence) and parents may care more efficiently by specializing in a subset of these activities. Our model predicts that efficient care specialization broadens the conditions under which biparental investment can evolve in lineages that historically had uniparental care. Major transitions in sex roles (e.g. from female-biased care with strong male mating competition to male-biased care with strong female competition) can arise following ecologically induced changes in the costs or benefits of different care types, or in the sex ratio at maturation. Our model provides a clear evolutionary mechanism for sex-role transitions, but also predicts that such transitions should be rare. It consequently contributes towards explaining widespread phylogenetic inertia in parenting and mating systems.

scholarly journals Actuarial senescence in a dimorphic bird: different rates of ageing in morphs with discrete reproductive strategies

2018 ◽  
Vol 285 (1892) ◽  
pp. 20182053 ◽  
Author(s):  
Melissa L. Grunst ◽  
Andrea S. Grunst ◽  
Vincent A. Formica ◽  
Marisa L. Korody ◽  
Adam M. Betuel ◽  
...  
Keyword(s):  
Parental Care ◽  
Parental Investment ◽  
Parental Support ◽  
Alternative Hypothesis ◽  
Mating Strategies ◽  
Competitive Strategies ◽  
Zonotrichia Albicollis ◽  
Sexual Competition ◽  
Senescence Rate ◽  
Genetically Determined

It is often hypothesized that intra-sexual competition accelerates actuarial senescence, or the increase in mortality rates with age. However, an alternative hypothesis is that parental investment is more important to determining senescence rates. We used a unique model system, the white-throated sparrow ( Zonotrichia albicollis ), to study variation in actuarial senescence. In this species, genetically determined morphs display discrete mating strategies and disassortative pairing, providing an excellent opportunity to test the predictions of the above hypotheses. Compared to tan-striped males, white-striped males are more polygynous and aggressive, and less parental. Tan-striped females receive less parental support, and invest more into parental care than white-striped females, which are also more aggressive. Thus, higher senescence rates in males and white-striped birds would support the intra-sexual competition hypothesis, whereas higher senescence rates in females and tan-striped birds would support the parental investment hypothesis. White-striped males showed the lowest rate of actuarial senescence. Tan-striped females had the highest senescence rate, and tan-striped males and white-striped females showed intermediate, relatively equal rates. Thus, results were inconsistent with sexual selection and competitive strategies increasing senescence rates, and instead indicate that senescence may be accelerated by female-biased parental care, and lessened by sharing of parental duties.

The Mating Game: A Classroom Activity for Undergraduates That Explores the Evolutionary Basis of Sex Roles

2012 ◽  
Vol 74 (9) ◽  
pp. 648-651 ◽  
Author(s):  
Dani Moore ◽  
C. Tate Holbrook ◽  
Melissa G. Meadows ◽  
Lisa A. Taylor
Keyword(s):  
Animal Behavior ◽  
Parental Investment ◽  
Reproductive Behavior ◽  
Sex Roles ◽  
Reproductive Output ◽  
Mating Strategies ◽  
Classroom Activity ◽  
Introductory Biology ◽  
Males And Females ◽  
Classroom Simulation

In species that reproduce sexually, an individual’s fitness depends on its ability to secure a mate (or mates). Although both males and females are selected to maximize their reproductive output, the mating strategies of the two sexes can differ dramatically. We present a classroom simulation that allows undergraduates to actively experience how differences in parental investment lead to differences in reproductive behavior. Students will understand why males generally compete for mates whereas females generally choose among mates. The activity provides a foundation for exploring advanced topics in animal behavior, or it can be adapted for introductory biology courses.

Mating strategies, parental investment and mutual ornamentation in Iberian Rock Sparrows (Petronia petronia)

Behaviour ◽  
2013 ◽  
Vol 150 (14) ◽  
pp. 1641-1663 ◽  
Author(s):  
Vicente García-Navas ◽  
Amanda García del Rincón ◽  
Esperanza S. Ferrer ◽  
Hicham Fathi
Keyword(s):  
Parental Care ◽  
Parental Investment ◽  
Paternal Care ◽  
Bird Species ◽  
Mating Strategies ◽  
Social Environments ◽  
Social Monogamy ◽  
Uniparental Care ◽  
Female Ornamentation ◽  
Brood Desertion

Relatively few bird species show complex social mating systems whose preponderance in a population is likely to affect the patterns of parental care observed there. In turn, parental investment is likely to be related to the expression of certain ornaments, which may reveal information on the bearer’s individual quality. Here we address both issues in a species characterised by several forms of parental care (both biparental and uniparental care) and in which both sexes possess a yellow breast patch, the rock sparrow (Petronia petronia). In our population, males contributed more to the care of the young in comparison with other populations. Social monogamy was the most frequent mating pattern and the percentage of cases of female (or male) brood desertion was lower with respect to that reported in previous studies, suggesting a flexible behaviour of this species to deal with different social environments. Birds did not pair assortatively with respect to the size of the yellow breast patch and we found no significant relationship between this trait and the frequency with which parents provisioned their chicks. However, we observed a positive relationship between male yellow patch size and nestling tarsus length, which suggests that more ornamented males are better parents. Males, but not females, differentially allocated parental investment in response to female ornamentation, although the benefits that males may gain from choosing more attractive females remain unidentified. Our results on paternal care investment along with previous studies on this species, reinforcing the view that the rock sparrow constitutes a good model to study sexual conflict over parental care under different social environments.

scholarly journals The evolution of avian parental care

2002 ◽  
Vol 357 (1419) ◽  
pp. 241-250 ◽  
Author(s):  
N. T. Burley ◽  
K. Johnson
Keyword(s):  
Parental Care ◽  
Parental Investment ◽  
Life History Traits ◽  
Stage Iv ◽  
Young Female ◽  
Cost Of Care ◽  
Biparental Care ◽  
Social Monogamy ◽  
Care Giving ◽  
Initial Cost

A stage model traces key behavioural tactics and life–history traits that are involved in the transition from promiscuity with no parental care, the mating system that typifies reptiles, to that typical of most birds, social monogamy with biparental care. In stage I, females assumed increasing parental investment in precocial young, female choice of mates increased, female–biased mating dispersal evolved and population sex ratios became male biased. In stage II, consortships between mating partners allowed males to attract rare social mates, provided a mechanism for paternity assessment and increased female ability to assess mate quality. In stage III, relative female scarcity enabled females to demand parental investment contributions from males having some paternity certainty. This innovation was facilitated by the nature of avian parental care; i.e. most care–giving activities can be adopted in small units. Moreover, the initial cost of care giving to males was small compared with its benefit to females. Males, however, tended to decline to assume non–partitionable, risky, or relatively costly parental activities. In stage IV, altriciality coevolved with increasing biparental care, resulting in social monogamy. Approaches for testing behavioural hypotheses are suggested.

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