Kin discrimination and sex ratios in a parasitoid wasp

Abstract

Sex ratio theory provides a clear and simple way to test if nonsocial haplodiploid wasps can discriminate between kin and nonkin. Specifically, if females can discriminate siblings from nonrelatives, then they are expected to produce a higher proportion of daughters if they mate with a sibling. This prediction arises because in haplodiploids, inbreeding (sib‐mating) causes a mother to be relatively more related to her daughters than her sons. Here we formally model this prediction for when multiple females lay eggs in a patch, and test it with the parasitoid wasp Nasonia vitripennis. Our results show that females do not adjust their sex ratio behaviour dependent upon whether they mate with a sibling or nonrelative, in response to either direct genetic or a range of indirect environmental cues. This suggests that females of N. vitripennis cannot discriminate between kin and nonkin. The implications of our results for the understanding of sex ratio and social evolution are discussed.

Patterns of split sex ratio in ants have multiple evolutionary causes based on different within-colony conflicts

“…For example, split sex ratio could occur owing to between-colony variation in the relative cost of male and gyne production (Nonacs 1986;Rosenheim et al 1996), caused by local mate competition (Frank 1987), inbreeding (Reece et al 2004) or variation in the cost of worker sex-ratio manipulation among colonies (Reuter et al 2004 . Selected examples of split sex-ratio patterns in ants in populations where colonies are characterized by: (a) having one singly mated queen and queen control (Pheidole desertorum, n ¼ 95); (b) variation in relatedness asymmetry (RA) and queen control (Formica selysi, n ¼ 65); (c) predominantly worker control and variation in RA due to variance in mating frequency (Formica exsecta (monogyne), n ¼ 38) or (d) queen number (Myrmica tahoensis, n ¼ 39); (e ) conflict among unrelated queens (Pheidole pallidula, n ¼ 21) and (f) conflict among related queens (Formica exsecta (polygyne), n ¼ 248).…”

Facultative Sex Ratio Adjustment in Natural Populations of Wasps: Cues of Local Mate Competition and the Precision of Adaptation

“…Hamilton (Hamilton 1967(Hamilton , 1979 Patch foundress number, * Greeff (Greeff 1996;Reece et al 2004) Relatedness to mating partner and foundress number…”

“…These assumptions implicitly constrain what information foundresses are thought to use. When these assumptions are relaxed, offspring sex ratios are predicted to vary within the patch, between individuals, and over time and space (Suzuki and Iwasa 1980;Werren 1980;Frank 1985bFrank , 1987Yamaguchi 1985;Stubblefield and Seger 1990;Taylor and Crespi 1994;Abe et al 2003;Reece et al 2004;Shuker et al 2005). For example, Werren (1980) demonstrated that, when two foundresses lay eggs sequentially on the same host, the sex ratio produced by the second foundress to lay eggs on the host should be negatively correlated with the relative size of her clutch (i.e., clutch laid by the second foundress divided by the clutch size of the first foundress).…”

“…Nasonia vitripennis is an ideal organism for such a study because it is known from both laboratory studies and field studies that the females adjust their sex ratios in response to the basic tenets of LMC (Werren 1983;Orzack et al 1991;Molbo and Parker 1996;Shuker and West 2004;Grillenberger et al 2008). Nasonia vitripennis has also been extremely useful in testing the more complex LMC models, but thus far these studies have been restricted to the laboratory (Werren 1980;Parker 1986, 1990;Flanagan et al 1998;Reece et al 2004;Shuker et al 2004aShuker et al , 2004bShuker et al , 2006Shuker et al , 2007. In our study we used the power and resolution of molecular techniques to test these extensions to LMC theory in the wild.…”

Comparison of Mating of Ten Eumeninae Wasp Species With a Brief Review of Sexual Selection Theories: A Framework for Future Research

“…At the same time, mothers do bear parental care and may be interested in haploid sons, because both daughters and inbred diploid sons are more costly (but see Reece et al 2004 for understanding of female-biased sex ratios in haplodiploid species). For instance, diploid male larvae of Philanthus triangulum cost twice as much as haploid males (Strohm & Linsenmair 1999.…”