Sexual Dimorphism in Life History: Age, Survival, and Reproduction in Male and Female Field Crickets Teleogryllus commodus under Seminatural Conditions

Males and females differ in their reproductive strategies. Accordingly, sexually dimorphic optima in the allocation of resources to reproduction should select for sex-specific life histories, including sex-specific resolution of the key trade-off between reproduction and longevity. While males are e...

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Bibliographic Details
Published in:The American naturalist 2009-06, Vol.173 (6), p.792-802
Main Authors: Zajitschek, Felix, Bonduriansky, Russell, Zajitschek, Susanne R. K., Brooks, Robert C.
Format: Article
Language:English
Subjects:
Animal and plant ecology
Animal reproduction
Animal, plant and microbial ecology
Animals
Biological and medical sciences
Entomology
Female
Fundamental and applied biological sciences. Psychology
Gender differences
General aspects
Gryllidae
Gryllidae - physiology
Insecta
Insects
Invertebrates
Longevity
Male
Models, Biological
Oviparity
Sex Characteristics
Sexual Behavior, Animal
Survival analysis
Teleogryllus commodus
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Summary:Males and females differ in their reproductive strategies. Accordingly, sexually dimorphic optima in the allocation of resources to reproduction should select for sex-specific life histories, including sex-specific resolution of the key trade-off between reproduction and longevity. While males are expected to increase reproductive effort with increasing age under sexual selection theory, female reproductive effort should rather decrease after maturity, due to waning selection pressure at older ages. Sex differences in reproductive trade-offs and in the external mortality hazards experienced during the population's evolutionary history are both likely to shape sex differences in reproductive and actuarial (age-specific mortality) aging. Despite the importance of small-bodied, short-lived animals as laboratory models for life-history and aging studies, very little is known about sex differences in life-history patterns under natural conditions. Here, we tested for sex-specific patterns of reproductive and actuarial aging in field crickets under near-natural conditions. Both males and females showed actuarial senescence, with females exhibiting more rapid aging than males but with a later onset. Female and male reproductive effort showed a senescent decrease, with the peaks at different ages. Our findings provide the first demonstration of sexual dimorphism in age-dependent patterns of both survival and reproduction in an insect under near-natural conditions.
ISSN:0003-0147
1537-5323
DOI:10.1086/598486