Tissue-dependent changes in oxidative damage with male reproductive effort in house mice

Theory suggests that reproductive effort generally increases with age, but life-history models indicate that other outcomes are possible. Empirical data are needed to quantify variation in actual age-dependence. Data are readily attainable for females (e.g. clutch per egg size), but not for males (e.g. courtship effort). To quantify male effort one must: (i) experimentally control for potential age-dependent changes in female presence; and, crucially, (ii) distinguish between the likelihood of courtship being initiated, the display rate, and the total time invested in courting before stopping (‘courtship persistence’). We provide a simple experimental protocol, suitable for many taxa, to illustrate how to obtain this information. We studied courtship waving by male fiddler crabs, Uca annulipes . Given indeterminate growth, body size is correlated with age. Larger males were more likely to wave at females and waved more persistently. They did not, however, have a higher courtship rate (waves per second). A known female preference for males with higher display rates explains why, once waving is initiated, all males display at the same rate.

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The effects of cues from kingsnakes on the reproductive effort of house mice

Current Zoology ◽

10.1093/czoolo/59.1.135 ◽

2013 ◽

Vol 59 (1) ◽

pp. 135-141 ◽

Cited By ~ 2

Author(s):

W. Wallace Starke ◽

Michael H. Ferkin

Keyword(s):

Mus Musculus ◽

Reproductive Effort ◽

Low Cost ◽

House Mice ◽

Inducible Defenses ◽

Fecal Material ◽

Male And Female ◽

Predator Cues ◽

Female Mice ◽

The Mean

Abstract It is not clear if rodents express inducible defenses in response to reptilian predators such as snakes. We tested the hypothesis that adult house mice Mus musculus decrease aspects of their reproductive effort upon 1 hour of exposure every 48 hours for a 25-day period to the fecal material and shed skins of a euryphagous ophidian predator, the kingsnake Lampropeltis getula, that had been fed mice. We found no significant differences in the total number of offspring born, the number of pups per litter, and the mean weight of pups in litters born to male and female mice that were exposed to predator cues and those mice that were not exposed to such cues. The lack of an inducible response may be associated with the low cost of an effective defense, or the lack of an effective defense against a generalist snake predator.

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The influence of male age and simulated pathogenic infection on producing a dishonest sexual signal

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2012.1914 ◽

2012 ◽

Vol 279 (1748) ◽

pp. 4740-4746 ◽

Cited By ~ 16

Author(s):

Emily K. Copeland ◽

Kenneth M. Fedorka

Keyword(s):

Reproductive Effort ◽

Reproductive Value ◽

Female Fitness ◽

Sexual Signal ◽

Terminal Investment ◽

Male Age ◽

Residual Reproductive Value ◽

Male Reproductive Effort ◽

Allonemobius Socius ◽

Pathogenic Infection

In recent years, studies have shown that reproductive effort decelerates in response to pathogenic infection. If infection substantially reduces a host's residual reproductive value (RRV), however, then an acceleration of effort may instead occur (e.g. terminal investment). Reproductive acceleration would theoretically allow hosts to maintain or exaggerate their sexual signal upon infection. This would create a deceptive message from the perspective of the chooser, who may unwittingly copulate with an infected mate to their detriment. Using the cricket Allonemobius socius , we assessed the potential for reduced RRV to accelerate male reproductive effort and create a dishonest signal. RRV was manipulated through male age and simulated pathogenic insult. Reproductive effort was measured as calling song energetics, mating success, latency to mate and nuptial gift size. We show that males adopted either an accelerated or decelerated reproductive strategy upon infection, and that this decision was probably mediated by RRV. Moreover, males who accelerated their effort produced a dishonest signal by increasing their song energetics while providing fewer paternal resources (i.e. smaller gifts). Our study is one of the few to document the existence of dishonest signals and relate dishonesty to a potential reduction in female fitness, underscoring the conflict inherent in sexual reproduction.

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