Abstract
Female mating with multiple males within a single fertile period is a common phenomenon in the animal kingdom. Female insects are particularly promiscuous. It is not clear why females mate with multiple partners despite several potential costs, such as expenditure of time and energy, reduced lifespan, risk of predation and contracting sexually transmitted diseases. Female red flour beetles (Tribolium castaneum) obtain sufficient sperm from a single insemination to retain fertility for several months. Nonetheless they copulate repeatedly within minutes with different males despite no direct fitness benefits from this behaviour. One hypothesis is that females mate with multiple partners to provide indirect benefits via enhanced offspring fitness. To test this hypothesis, we compared the relative fitness of F(1) offspring from females mated with single males and multiple males (2, 4, 8, or 16 partners), under the condition of relatively high intraspecific competition. We found that a female mating with 16 males enhanced the relative fitness of F(1) males (in two out of three trials) but reduced F(1) females' fitness (in two independent trials) in comparison with singly mated females. We also determined whether several important fitness correlates were affected by polyandry. We found that F(1) males from mothers with 16 partners inseminated more females than F(1) males from mothers with a single partner. The viability of the eggs sired or produced by F(1) males and females from highly polyandrous mothers was also increased under conditions of low intra-specific competition. Thus, the effects of polyandry on F(1) offspring fitness depend on environmental conditions. Our results demonstrated a fitness trade-off between male and female offspring from polyandrous mothers in a competitive environment. The mechanisms and biological significance of this unique phenomenon are discussed.
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Selected References
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- Chapman T., Liddle L. F., Kalb J. M., Wolfner M. F., Partridge L. Cost of mating in Drosophila melanogaster females is mediated by male accessory gland products. Nature. 1995 Jan 19;373(6511):241–244. doi: 10.1038/373241a0. [DOI] [PubMed] [Google Scholar]
- Chippindale A. K., Gibson J. R., Rice W. R. Negative genetic correlation for adult fitness between sexes reveals ontogenetic conflict in Drosophila. Proc Natl Acad Sci U S A. 2001 Jan 30;98(4):1671–1675. doi: 10.1073/pnas.041378098. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cunningham E. J., Russell A. F. Egg investment is influenced by male attractiveness in the mallard. Nature. 2000 Mar 2;404(6773):74–77. doi: 10.1038/35003565. [DOI] [PubMed] [Google Scholar]
- Edvardsson M., Arnqvist G. Copulatory courtship and cryptic female choice in red flour beetles Tribolium castaneum. Proc Biol Sci. 2000 Mar 22;267(1443):559–563. doi: 10.1098/rspb.2000.1037. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jennions M. D., Petrie M. Why do females mate multiply? A review of the genetic benefits. Biol Rev Camb Philos Soc. 2000 Feb;75(1):21–64. doi: 10.1017/s0006323199005423. [DOI] [PubMed] [Google Scholar]
- M DK. Non-genetic benefits of mate choice: fecundity enhancement and sexy sons. Anim Behav. 1998 May;55(5):1191–1201. doi: 10.1006/anbe.1997.0681. [DOI] [PubMed] [Google Scholar]
- doi: 10.1098/rspb.1999.0761. [DOI] [PMC free article] [Google Scholar]