Large Numbers of Matings Give Female Field Crickets a Direct Benefit but not a Genetic Benefit

Journal of Insect Behavior, Jan 2010

Female crickets can potentially gain both direct and indirect benefits from mating multiple times with different males. Most studies have only examined the effects of small numbers of matings, although female crickets are capable of mating many times. The goal of this paper is to examine the direct and indirect benefits of mating large numbers of times for female reproductive success. In a previous experiment, female Gryllus vocalis were found to gain diminishing direct benefits from mating large numbers of times. In this study I attempt to determine whether mating large numbers of times yields similar diminishing returns on female indirect benefits. Virgin female Gryllus vocalis crickets were assigned to mate five, ten or 15 times with either the same or different males. Females that mated more times gained direct benefits in terms of laying more eggs and more fertilized eggs. Females that mated with different males rather than mating repeatedly with the same male did not have higher offspring hatching success, a result that is contrary to other published results comparing female reproductive success with repeated versus different partners. These results suggest that females that mate large numbers of times fail to gain additional genetic benefits from doing so.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

http://link.springer.com/content/pdf/10.1007%2Fs10905-009-9195-y.pdf

Large Numbers of Matings Give Female Field Crickets a Direct Benefit but not a Genetic Benefit

Susan N. Gershman 0 0 S. N. Gershman Department of Biology, University of California , Riverside, Riverside, CA, USA 1 ) School of Biological Sciences, Illinois State University , Normal, IL 61790-4120, USA Female crickets can potentially gain both direct and indirect benefits from mating multiple times with different males. Most studies have only examined the effects of small numbers of matings, although female crickets are capable of mating many times. The goal of this paper is to examine the direct and indirect benefits of mating large numbers of times for female reproductive success. In a previous experiment, female Gryllus vocalis were found to gain diminishing direct benefits from mating large numbers of times. In this study I attempt to determine whether mating large numbers of times yields similar diminishing returns on female indirect benefits. Virgin female Gryllus vocalis crickets were assigned to mate five, ten or 15 times with either the same or different males. Females that mated more times gained direct benefits in terms of laying more eggs and more fertilized eggs. Females that mated with different males rather than mating repeatedly with the same male did not have higher offspring hatching success, a result that is contrary to other published results comparing female reproductive success with repeated versus different partners. These results suggest that females that mate large numbers of times fail to gain additional genetic benefits from doing so. - Mating multiple times can be beneficial for females. By mating more than once, females can gain direct benefits (Arnqvist and Nilsson 2000), such as replenishment of depleted sperm stores, access to male-held resources, food and chemical gifts (Vahed 1998). Females can also gain indirect or genetic benefits from mating with multiple partners. Females that have already mated may trade-up by mating with or selectively using sperm from successively more genetically beneficial males as they encounter them in the environment. Females may choose mates that provide their mutual offspring with superior genes or females may seek combinations of maternal and paternal genes to avoid genetic incompatibility or increase offspring heterozygosity (Yasui 1998; Jennions and Petrie 2000; Mays and Hill 2004). If male fertilization success is correlated with offspring viability, females that mate multiple times and allow sperm competition to determine offspring paternity will have more viable offspring than females that mate with a single male Sivinski (1984). Alternatively, by genetic bet-hedging, a female that mates multiple times may potentially improve her fitness by creating genetically diverse offspring that can survive unpredictable environmental conditions in the future (Jennions and Petrie 2000). However, mating with multiple partners can also be costly for females (Sakaluk 1990), thus it is expected that females mate only as often as needed to maximize fitness. Field cricket females can mate large numbers of times. Based on molecular analysis of wild caught female Gryllus bimaculatus, females may mate as many as seven times (Bretman and Tregenza 2005), and based on an enclosure study, female Gryllodes sigillatus may mate as many times as 15 times in a lifetime (Sakaluk et al. 2002). However, the effects of large numbers of matings on female lifetime reproductive success are generally overlooked (Arnqvist and Nilsson 2000). In past studies of Gryllus vocalis, females that mated many times gained diminishing direct benefits from doing so: females gained fecundity and fertility benefits from mating up to ten times, but failed to gain additional benefits from more matings (Gershman 2007a). However, the consequences of G. vocalis females mating multiply with different partners rather than repeatedly with the same male have not been explored. In this paper, I examine whether females are willing to mate more times than maximizes their direct benefits because these large numbers of matings provide genetic benefits. Alternatively, females may gain diminishing genetic benefits from mating large numbers of times. One experimental approach used to separate direct from indirect benefits is to control the number of times that females mate, but vary the number of mating partners. This approach holds constant the effect of the direct benefits that females receive from mating, but varies the genetic contributions of partners. If females gain genetic benefits, females mating with multiple partners should have increased offspring viability as compared to females mated with a single partner (Sivinski 1984). Past studies in which female crickets were paired repeatedly with the same partner versus multiply with different partners show that females that mate with more partners have more offspring that successfully hatch (Tregenza and Wedell 1998; Simmons 2001; Fedorka and Mosseau 2002) and/or higher offspring survival to adulthood (Ivy and Sakaluk 2005; Fedorka and Mosse (...truncated)


This is a preview of a remote PDF: http://link.springer.com/content/pdf/10.1007%2Fs10905-009-9195-y.pdf

Susan N. Gershman. Large Numbers of Matings Give Female Field Crickets a Direct Benefit but not a Genetic Benefit, Journal of Insect Behavior, 2010, pp. 59-68, Volume 23, Issue 1, DOI: 10.1007/s10905-009-9195-y