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

David R. Horton

doi:10.4039/tce.2012.91

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

The Canadian Entomologist ◽

10.4039/tce.2012.91 ◽

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.

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

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2017.0041 ◽

2017 ◽

Vol 372 (1729) ◽

pp. 20170041 ◽

Cited By ~ 10

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’.

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

Journal of Insect Behavior ◽

10.1007/bf01049193 ◽

1990 ◽

Vol 3 (1) ◽

pp. 33-48 ◽

Cited By ~ 18

Author(s):

Scott P. Carroll ◽

Jenella E. Loye

Keyword(s):

Sex Ratios ◽

Mate Guarding ◽

Female Promiscuity

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

Behaviour ◽

10.1163/156853996x00125 ◽

1996 ◽

Vol 133 (3-4) ◽

pp. 221-239 ◽

Cited By ~ 9

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.

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

Behaviour ◽

10.1163/1568539x-00003247 ◽

2015 ◽

Vol 152 (5) ◽

pp. 653-666 ◽

Cited By ~ 6

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.

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Prolonged copulation and the internal dynamics of sperm transfer in the water strider Aquarius remigis

Canadian Journal of Zoology ◽

10.1139/z01-148 ◽

2001 ◽

Vol 79 (10) ◽

pp. 1801-1812 ◽

Cited By ~ 16

Author(s):

Veronique Campbell ◽

Daphne J Fairbairn

Keyword(s):

Mate Guarding ◽

Adaptive Significance ◽

Water Strider ◽

Costs And Benefits ◽

Storage Organ ◽

Natural Conditions ◽

Aquarius Remigis ◽

Prolonged Copulation ◽

New Interpretation ◽

And Storage

Copulations lasting much longer than required to effect insemination are common throughout the Insecta, but their adaptive significance remains obscure. We address the hypothesis that prolonged copulations benefit male Aquarius remigis (Hemiptera, Gerridae) by influencing sperm use and storage following insemination. We describe the gynatrial complex of females and document sperm location immediately following 32 naturally terminated and 25 artificially terminated copulations. We also examine sperm storage in 22 females isolated from males for 210 days. Our results demonstrate that insemination occurs at the end of copulation, and therefore that prolonged copulation is not a post-insemination mate-guarding tactic, as was previously assumed. Sperm are transferred in a coherent, coiled mass and move rapidly to the spermathecal tube, the primary storage organ. However, a few sperm move directly to the fecundation canal and hence should be capable of immediate fertilization. Prolonged copulation is associated with increased filling of the spermathecal tube, which may indicate some form of copulatory courtship or sperm loading by males during the prolonged pre-insemination phase. We discuss this new interpretation of prolonged copulation in A. remigis in the context of the overall costs and benefits of prolonged copulation for both sexes under the natural conditions of polygynandry.

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Grandmothering life histories and human pair bonding

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1599993112 ◽

2015 ◽

Vol 112 (38) ◽

pp. 11806-11811 ◽

Cited By ~ 23

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.

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