scholarly journals Male-biased sex ratios, female promiscuity, and copulatory mate guarding in an aggregating tropical bug,Dysdercus bimaculatus

1990 ◽  
Vol 3 (1) ◽  
pp. 33-48 ◽  
Author(s):  
Scott P. Carroll ◽  
Jenella E. Loye
Keyword(s):  
Sex Ratios ◽  
Mate Guarding ◽  
Female Promiscuity

Copulation calls in wild Mueller’s gibbons (Hylobates muelleri)

2019 ◽  
Vol 20 (2) ◽  
pp. 362-374
Author(s):  
Yoichi Inoue ◽  
Waidi Sinun ◽  
Kazuo Okanoya
Keyword(s):  
Mating System ◽  
Social Organization ◽  
Sperm Competition ◽  
Mate Guarding ◽  
Conservation Area ◽  
Mating Activity ◽  
Selective Pressures ◽  
Female Promiscuity ◽  
Vocal Signals ◽  
The Relationship

Abstract Mating activity of a wild Mueller’s gibbon group (Hylobates muelleri) was observed in the Danum Valley Conservation Area, Sabah, Malaysia. The purpose of this study was to investigate the function of copulation calls in gibbons. The female emitted copulation calls at the time of intromission and pelvic thrusting. Copulation calls were composed of two notes and one of them was sung only while mating. Approximately half of copulation calls were sung near the range boundary. Mating with copulation calls sometimes occurred while singing. According to the model that female copulation calls have evolved under the selective pressures of risk of infanticide and sperm competition, copulation calls should be rare in species with little female promiscuity. As gibbons usually live in pair-living social organization and have a monogamous mating system, no vocal signals by female gibbons are considered to be needed. However, clear copulation calls were emitted by the female. It suggests that the relationship between paired gibbons is unstable. Copulation calls by the female Mueller’s gibbon may function to increase mate guarding and strengthen the pair bond.

scholarly journals Evolution of male strategies with sex-ratio–dependent pay-offs: connecting pair bonds with grandmothering

2017 ◽  
Vol 372 (1729) ◽  
pp. 20170041 ◽  
Author(s):  
Sara L. Loo ◽  
Kristen Hawkes ◽  
Peter S. Kim
Keyword(s):  
Life History ◽  
Sex Ratio ◽  
Human Evolution ◽  
Paternal Care ◽  
Multiple Mating ◽  
Sex Ratios ◽  
Mate Guarding ◽  
Equation Model ◽  
Pair Bonding ◽  
Pair Bonds

Men's provisioning of mates and offspring has been central to ideas about human evolution because paternal provisioning is absent in our closest evolutionary cousins, the great apes, and is widely assumed to result in pair bonding, which distinguishes us from them. Yet mathematical modelling has shown that paternal care does not readily spread in populations where competition for multiple mates is the common male strategy. Here we add to models that point to the mating sex ratio as an explanation for pairing as pay-offs to mate guarding rise with a male-biased sex ratio. This is of interest for human evolution because our grandmothering life history shifts the mating sex ratio from female- to male-biased. Using a difference equation model, we explore the relative pay-offs for three competing male strategies (dependant care, multiple mating, mate guarding) in response to changing adult sex ratios. When fertile females are abundant, multiple mating prevails. As they become scarce, mate guarding triumphs. The threshold for this shift depends on guarding efficiency. Combined with mating sex ratios of hunter–gatherer and chimpanzee populations, these results strengthen the hypothesis that the evolution of our grandmothering life history propelled the shift to pair bonding in the human lineage. This article is part of the themed issue ‘Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies’.

Previous exposure to other males leads to prolonged copulation by a predatory true bug (Hemiptera: Heteroptera: Anthocoridae)

2012 ◽  
Vol 145 (1) ◽  
pp. 88-93
Author(s):  
David R. Horton
Keyword(s):  
Sex Ratios ◽  
Mate Guarding ◽  
Previous Exposure ◽  
Prolonged Copulation

AbstractMating pairs ofAnthocoris whiteiReuter (Hemiptera: Heteroptera: Anthocoridae) irregularly exhibit copulations exceeding five hours in duration. In other Heteroptera, male-biased sex ratios or high densities of male conspecifics may lead to prolonged copulation. I tested whether exposure to conspecific males preceding access to females led to prolonged copulations byA. whitei. Copulations in which the male had been exposed to other males were significantly longer (by 60+ minutes) than copulations in which the male had not been exposed to other males. Durations exceeded five hours in several pairings following exposure to other males. Almost 75% of copulations in which males had not been exposed to other males were <100 minutes in duration, whereas only 22%–29% of copulations involving males that had been exposed to other males were <100 minutes in duration. Atypically long copulations by this species may be a form of postinsemination mate guarding to prevent insemination of a guarded female by other males.

scholarly journals Promiscuous mating in feral pigs (Sus scrofa) from Texas, USA

2010 ◽  
Vol 37 (7) ◽  
pp. 539 ◽  
Author(s):  
Johanna Delgado-Acevedo ◽  
Angeline Zamorano ◽  
Randy W. DeYoung ◽  
Tyler A. Campbell ◽  
David G. Hewitt ◽  
...  
Keyword(s):  
Management Strategies ◽  
Multiple Paternity ◽  
Mate Guarding ◽  
Fertility Control ◽  
Mating Strategies ◽  
Male Mating ◽  
Factors Affecting ◽  
Feral Pigs ◽  
Female Promiscuity ◽  
Gestation Time

Context Feral pigs represent a significant threat to agriculture and ecosystems and are disease reservoirs for pathogens affecting humans, livestock and other wildlife. Information on the behavioural ecology of feral pigs might increase the efficiency and effectiveness of management strategies. Aims We assessed the frequency of promiscuous mating in relation to oestrous synchrony in feral pigs from southern Texas, USA, an agroecosystem with a widespread and well established population of feral pigs. An association between multiple paternity of single litters and synchrony of oestrous may indicate alternative mating strategies, such as mate-guarding. Methods We collected gravid sows at nine sites in southern Texas during 2005–07. We used a panel of DNA microsatellite markers to estimate frequency of multiple paternity and the distribution of male mating among litters of feral pigs. Conception dates were determined by fitting average fetal crown–rump measurements within litters to expected fetal development relative to gestation time. Key results We found evidence of multiple paternity in 21 of 64 litters (33%) from seven of nine sites sampled. Synchrony of oestrous did not influence promiscuous mating, as we found multiple paternity at sites with synchronous and asynchronous oestrous. Males sired from 8 to 11 offspring at three sites where >10 litters were sampled. Mean litter size (5.4) was less than the best-fit value for the number of offspring, indicating that some males sired offspring with ≥ 2 females. Key conclusions Feral pigs in Texas appear to be promiscuous under a range of demographic conditions, unlike wild boar and feral pigs in other regions. The ecological and behavioural factors affecting multiple paternity are not clear, but may include male–male competition, harassment avoidance, genetic benefits for offspring, response to macro-habitat conditions, or selection. Implications A high incidence of sexual contact among individuals may increase the opportunity for diseases transmitted by oral or venereal routes, such as swine brucellosis and pseudorabies. In addition, fertility-control methods targeting males only are likely to be inefficient if female promiscuity is high; methods targeting females or both sexes jointly may be more effective.

Male Mate Choice in a Natural Population of the Parasitic Copepod Lernaeocera Branchialis (Copepoda: Pennellidae)

Behaviour ◽  
1996 ◽  
Vol 133 (3-4) ◽  
pp. 221-239 ◽  
Author(s):  
Thomas A. Schram ◽  
Peter Andreas Heuch
Keyword(s):  
Mate Choice ◽  
Natural Population ◽  
Sex Ratios ◽  
Mate Guarding ◽  
Parasitic Copepod ◽  
Male Mate Choice ◽  
Adult Males ◽  
Larval Stages ◽  
Adult Females ◽  
Male Mate

AbstractVariations in age and sex structure of a natural population of the copepod Lernaeocera branchialis, parasitic on flounder, Platichthys flesus were examined in a 15-month study. Recent laboratory studies and literature on reproductive strategies indicate that male mate choice in this species should depend on the sex ratios of the parasite on its hosts, and on the age and mating status of females. Sex ratios suggested a strong intra-male competition for females. The ratio of chalimus 4 and virgin adult females (preferred stages) to adult males exceeded 1 female: 4 males on 50% of the hosts. In four out of the six sampling periods, more than 50% of hosts harboured more adult males than the total number of females. The males preference for the different female stages was estimated from the number of precopula and copula associations. The data were fitted to a logistic regression model. At most sex ratios, males preferred chalimus 4 and virgin adult females, and discriminated against younger stages. Mated females were about as attractive as the youngest larval stages at female-biased sex ratios, but they were chosen more frequently at strongly male-biased sex ratios. Most adult L. branchialis females had copulated more than once, and some had accommodated at least 5 ejaculates in the their sperm storage organs. The patterns of mate guarding and potential for sperm competition strongly suggest that L. branchialis males take the intrasexual competition into account when choosing mates. On this basis, they minimize guarding time and maximize the possibility of paternity.

Male-biased sex ratios and plasticity in post-insemination behaviour in the New Zealand stick insect Micrarchus hystriculeus

Behaviour ◽  
2015 ◽  
Vol 152 (5) ◽  
pp. 653-666 ◽  
Author(s):  
Clint D. Kelly
Keyword(s):  
Sex Ratio ◽  
Sperm Competition ◽  
Laboratory Experiments ◽  
Sex Ratios ◽  
Mate Guarding ◽  
Stick Insect ◽  
Encounter Rate ◽  
Mate Fidelity ◽  
Biased Sex Ratio ◽  
Increasing Risk

The duration of mate guarding by males is predicted to vary in accordance with the risk of sperm competition or mate encounter rate. Mate guarding is predicted to be prolonged under a male-biased sex ratio because the risk of sperm competition is high or the mate encounter rate is low. A consistently male-biased sex ratio should thus select for greater mate fidelity, and reduced plasticity in guarding behaviour, by males. Micrarchus hystriculeus Westwood (Phasmatodea) is a sexually size dimorphic stick insect in which males form prolonged post-insemination associations with their mates and whose populations have a consistently male-biased sex ratio. My laboratory experiments showed, as predicted, little plasticity by males in the duration of their post-insemination association. Although mate guarding duration is similar under male- and female-biased sex ratios, males clasped the genitalia of their mates significantly more often under a male-biased sex ratio, suggesting that males intensify their guarding with increasing risk of sperm competition.

scholarly journals Grandmothering life histories and human pair bonding

2015 ◽  
Vol 112 (38) ◽  
pp. 11806-11811 ◽  
Author(s):  
James E. Coxworth ◽  
Peter S. Kim ◽  
John S. McQueen ◽  
Kristen Hawkes
Keyword(s):  
Life History ◽  
Life Histories ◽  
Human Life ◽  
Sex Ratios ◽  
Mate Guarding ◽  
Human Female ◽  
Hunter Gatherers ◽  
Agent Based ◽  
Pair Bonds ◽  
Grandmother Hypothesis

The evolution of distinctively human life history and social organization is generally attributed to paternal provisioning based on pair bonds. Here we develop an alternative argument that connects the evolution of human pair bonds to the male-biased mating sex ratios that accompanied the evolution of human life history. We simulate an agent-based model of the grandmother hypothesis, compare simulated sex ratios to data on great apes and human hunter–gatherers, and note associations between a preponderance of males and mate guarding across taxa. Then we explore a recent model that highlights the importance of mating sex ratios for differences between birds and mammals and conclude that lessons for human evolution cannot ignore mammalian reproductive constraints. In contradiction to our claim that male-biased sex ratios are characteristically human, female-biased ratios are reported in some populations. We consider the likelihood that fertile men are undercounted and conclude that the mate-guarding hypothesis for human pair bonds gains strength from explicit links with our grandmothering life history.

Conservation Status and Sex Ratios of the Coahuila Box Turtle (Terrapene coahuila) in the Cuatro Ciénegas Valley of Coahuila, Mexico, 2011–2018

2020 ◽  
Vol 19 (1) ◽  
pp. 14
Author(s):  
Gamaliel Castañeda Gaytan ◽  
Ernesto Becerra-López ◽  
Sara Valenzuela-Ceballos ◽  
Miguel Borja-Jiménez ◽  
Bruno Rodríguez-López ◽  
...  
Keyword(s):  
Conservation Status ◽  
Sex Ratios ◽  
Box Turtle ◽  
Cuatro Ciénegas
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