Density‐Dependent Male Mating Harassment, Female Resistance, and Male Mimicry

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.

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Density-dependent mating behaviors reduce male mating harassment in locusts

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2104673118 ◽

2021 ◽

Vol 118 (42) ◽

pp. e2104673118

Author(s):

Koutaro Ould Maeno ◽

Cyril Piou ◽

Sidi Ould Ely ◽

Sid’Ahmed Ould Mohamed ◽

Mohamed El Hacen Jaavar ◽

...

Keyword(s):

Gravid Female ◽

Male Mating ◽

Group Separation ◽

Density Dependent ◽

Gregarious Behavior ◽

Open Ground ◽

Pair Mating ◽

Behavioral Group ◽

Mating Behaviors ◽

Gravid Females

Male mating harassment may occur when females and males do not have the same mating objectives. Communal animals need to manage the costs of male mating harassment. Here, we demonstrate how desert locusts in dense populations reduce such conflicts through behaviors. In transient populations (of solitarious morphology but gregarious behavior), we found that nongravid females occupied separate sites far from males and were not mating, whereas males aggregated on open ground (leks), waiting for gravid females to enter the lekking sites. Once a male mounted a gravid female, no other males attacked the pair; mating pairs were thereby protected during the vulnerable time of oviposition. In comparison, solitarious locusts displayed a balanced sex ratio in low-density populations, and females mated irrespective of their ovarian state. Our results indicate that the mating behaviors of desert locusts are density dependent and that sex-biased behavioral group separation may minimize the costs of male mating harassment and competition.

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Density-dependent costs and benefits of male mating success in a wild insect

10.1101/733832 ◽

2019 ◽

Author(s):

Petri T. Niemelä ◽

Stefano Tiso ◽

Niels J. Dingemanse

Keyword(s):

Mating Success ◽

Allee Effect ◽

Local Density ◽

Field Cricket ◽

Male Mating ◽

Male Mating Success ◽

Costs And Benefits ◽

Density Dependent ◽

Effect Theory ◽

Local Densities

AbstractSocial environments are important determinant of fitness, particularly when same-sex local densities shape both mating success and survival costs.We studied how mating success varied across a range of naturally occurring local male densities in wild field cricket males, Gryllus campestris, monitored by using fully automated RFID-surveillance system. We predicted that mating success as a function of local density follow a concave pattern predicted by the Allee-effect theory. As increasing density should reduce per capita predation and parasitism risk, we predicted that males generally having high mating success in low (versus high) local density live less long. Finally, we predicted that males on average occurred in local densities where their mating success is highest.Male mating success followed a density-dependent pattern predicted by the Allee-effect theory. Males also differed in the local density where their mating success was highest. This variation explained longevity and total fitness: males with high mating success in low local density lived longer and had higher total mating success. Finally, we found no evidence of males occupying local densities in which their mating success is highest.Our study suggest that density-dependent plasticity in mating success is under selection: males having high mating success in low density, but low mating success in high density, lived longer and had higher overall mating success. We thus provide novel insights, with unseen detail, about individual differences in density-dependent mating success and, costs and benefits related to variation in mating success in the wild. Finally, our study also highlights that specific statistical approaches are needed to firmly study the costs and benefits associated with the traits that are repeatedly expressed across range of environments.

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FEMALE RESISTANCE AND MATING OUTCOMES IN A STREAM-DWELLING ISOPOD: EFFECTS OF MALE ENERGY RESERVES AND MATING HISTORY

Behaviour ◽

10.1163/156853902320387873 ◽

2002 ◽

Vol 139 (7) ◽

pp. 875-895 ◽

Cited By ~ 19

Author(s):

Tyler Orsburn ◽

Timothy Sparkes ◽

Daniel Keogh

Keyword(s):

Fertilization Success ◽

Low Energy ◽

Male Mating ◽

Energy Costs ◽

Energy Reserves ◽

Female Resistance ◽

Mating History ◽

Race Track ◽

Males And Females ◽

The Relationship

AbstractIn the stream-dwelling isopod, Lirceus fontinalis, conspicuous mating contests occur between males and females prior to pair formation. Our previous work has shown that female resistance during contests determines contest outcomes. Here we examined whether female resistance could act as a mechanism of choice in which females discriminate against males with low energy (glycogen) reserves. We manipulated male glycogen levels by chasing males around a race-track then exposed females to males that differed in glycogen levels. We found that high-glycogen males were more successful than low-glycogen males and that this effect appeared to be due to increased female resistance towards low-glycogen males. We then examined one potential benefit to females of energy-based mate discrimination. In L. fontinalis, male mating history and levels of glycogen reserves are correlated, i.e. recently mated males are glycogen-depleted due to energy costs associated with mating. We examined whether recently mated males were also costly mates, and thus should be avoided by females. We quantified the relationship between male mating history and female fertilization success and found that females suffered an 18% reduction in fertilization success by mating with a male that had recently inseminated another female. We propose that female resistance could act as a mechanism of choice in which males with low energy reserves are avoided and that one benefit of this discrimination is that females increase fertilization success be avoiding males that have recently mated.

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The evolution of optimal female mating rate changes the coevolutionary dynamics of female resistance and male persistence

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2012.0219 ◽

2012 ◽

Vol 367 (1600) ◽

pp. 2339-2347 ◽

Cited By ~ 7

Author(s):

Erem Kazancıoğlu ◽

Suzanne H. Alonzo

Keyword(s):

Sexual Conflict ◽

Mating Success ◽

Male Mating ◽

Theoretical Studies ◽

Male Mating Success ◽

Female Resistance ◽

Previous Theory ◽

Mating Rate ◽

Mating Patterns ◽

Female Mating

Mating decisions usually involve conflict of interests between sexes. Accordingly, males benefit from increased number of matings, whereas costs of mating favour a lower mating rate for females. The resulting sexual conflict underlies the coevolution of male traits that affect male mating success (‘persistence’) and female traits that affect female mating patterns (‘resistance’). Theoretical studies on the coevolutionary dynamics of male persistence and female resistance assumed that costs of mating and, consequently, the optimal female mating rate are evolutionarily constant. Costs of mating, however, are often caused by male ‘persistence’ traits that determine mating success. Here, we present a model where the magnitude of costs of mating depend on, and evolve with, male persistence. We find that allowing costs of mating to depend on male persistence results in qualitatively different coevolutionary dynamics. Specifically, we find that male traits such as penis spikes that harm females are not predicted to exhibit runaway selection with female resistance, in contrast to previous theory that predicts indefinite escalation. We argue that it is essential to determine when and to what extent costs of mating are caused by male persistence in order to understand and accurately predict coevolutionary dynamics of traits involved in mating decisions.

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SITUATION EXPLOITATION: HIGHER MALE MATING SUCCESS WHEN FEMALE RESISTANCE IS REDUCED BY FEEDING

Evolution ◽

10.1111/j.1558-5646.2008.00502.x ◽

2009 ◽

Vol 63 (1) ◽

pp. 29-39 ◽

Cited By ~ 45

Author(s):

Klaus Reinhardt ◽

Richard A. Naylor ◽

Michael T. Siva-Jothy

Keyword(s):

Mating Success ◽

Male Mating ◽

Male Mating Success ◽

Female Resistance

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Temporal dynamics of intersexual conflict and the effect of male quality on female fecundity in the marine isopod Cleantiella isopus

Behaviour ◽

10.1163/1568539x-00003364 ◽

2016 ◽

Vol 153 (5) ◽

pp. 569-589 ◽

Cited By ~ 1

Author(s):

Y. Miura ◽

S. Goshima

Keyword(s):

Temporal Dynamics ◽

Mating Frequency ◽

Male Mating ◽

Relative Importance ◽

Female Fitness ◽

Male Size ◽

Female Fecundity ◽

Female Resistance ◽

Mate Quality ◽

Intersexual Conflict

Crustacean males grasp and/or guard females before copulation to ensure mating, but females typically resist males during pair formation. The benefit of resistance for females might allow (1) females to optimize mate quality, or (2) to avoid costs incurred during guarding. However, it has not been fully investigated which benefits actually improve female fitness. Here we investigated female resistance, temporal dynamics of intersexual conflict during reproduction, and the effect of male size and male mating frequency on female fecundity in the marine isopod,Cleantiella isopusto examine the relative importance of the two mechanisms mentioned before. Females resisted even after they had become receptive. Females which mated with small males showed lower fecundity than the ones with large males, and small males were frequently unable to form pairs. These results suggest that female resistance ofC. isopusagainst males can function as a way to optimize mate quality.

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The Effects of the sphragis on male and female genitalia in Acraea (Nymphalidae) butterflies

UF Journal of Undergraduate Research ◽

10.32473/ufjur.v22i0.121244 ◽

2020 ◽

Vol 22 ◽

Author(s):

Shannon L Summers ◽

Akito Y Kawahara ◽

Ana P. S. Carvalho

Keyword(s):

Interspecific Variation ◽

Sperm Storage ◽

Male Mating ◽

Museum Collections ◽

Storage Organ ◽

Mating Plug ◽

Males And Females ◽

Comparison And Analysis ◽

Imagej Software ◽

Sexually Antagonistic Coevolution

Male mating plugs have been used in many species to prevent female re-mating and sperm competition. One of the most extreme examples of a mating plug is the sphragis, which is a large, complex and externalized plug found only in butterflies. This structure is found in many species in the genus Acraea (Nymphalidae) and provides an opportunity for investigation of the effects of the sphragis on the morphology of the genitalia, which is poorly understood. This study aims to understand morphological interspecific variation in the genitalia of Acraea butterflies. Using specimens from museum collections, abdomen dissections were conducted on 19 species of Acraea: 9 sphragis bearing and 10 non-sphragis bearing species. Genitalia imaging was performed for easier comparison and analysis and measurements of genitalia structures was done using ImageJ software. Some distinguishing morphological features in the females were found. The most obvious difference is the larger and more externalized copulatory opening in sphragis bearing species, with varying degrees of external projections. Females of the sphragis bearing species also tend to have a shorter ductus (the structure that connects the copulatory opening with the sperm storage organ) than those without the sphragis. These differences may be due to a sexually antagonistic coevolution between the males and females, where the females evolve larger and more difficult to plug copulatory openings and the males attempt to prevent re-mating with the sphragis.

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