Egg size variation does not affect offspring performance under intraspecific competition in Nasonia vitripennis, a gregarious parasitoid

Abstract

Summary 1.As with many insects, egg size variation is correlated with body size in the gregarious parasitoid, Nasonia vitripennis . I use this feature to test the hypothesis that egg size differences among parents affects the ability of their larvae to compete for limited resources within a superparasitized host. 2. I show that egg size asymmetries in parents that oviposit into the same host have no detectable effect on relative offspring performance, even under conditions of resource limitation. 3. Broods within a host that were initiated earlier attained greater average size than competing broods in the same host that were initiated later. 4. Individuals in the more numerous brood emerged consistently larger than individuals in the less numerous brood. 5. The possibility that siblings cooperate in competing for limited resources within a host and the potential role of sibling cooperation on egg size evolution is discussed.

Body size-specific maternal effects on the offspring environment shape juvenile phenotypes in Atlantic salmon

“…In some taxa, mothers of all sizes may even adjust egg size and fecundity in anticipation of the offspring competitive environment (e.g., Creighton 2005;Leips et al 2009), while in other taxa, mothers do not (e.g., Plaistow et al 2007). To our knowledge, however, few experimental studies have been designed specifically to address whether the egg size-maternal size correlation is a form of maternal compensation for increased sibling competition, and none have lent support to this hypothesis (Lalonde 2005;Rollinson and Hutchings 2011). Similarly, the present study shows that the increase in egg size with maternal size in Atlantic salmon cannot be explained as a plastic response to maternally-induced differences in the quality of the offsprings' physical environment, at least with respect to the two factors we tested.…”

“…For example, larger mothers may generally have greater fitness because of size-related increases in fecundity, but larger more fecund mothers may reduce the quality of their offspring's environment by increasing sibling competition (Parker and Begon 1986;Hendry and Day 2003;Kindsvater et al 2010). Hence, when egg or juvenile dispersal is limited, larger mothers may increase per-offspring investment to offset the negative effects of sibling competition, whereas no such compensation would be necessary for smaller, less fecund mothers Hendry and Day 2003;Leips et al 2009; but see Lalonde 2005). In other words, when maternal body size 'predicts' the offspring environment, a positive relationship between maternal size and optimal egg size may exist (Parker and Begon 1986;Hendry et al 2001;Rollinson and Brooks 2008).…”

Maternal and stock effects on egg-size variation among walleye Sander vitreus stocks from the Great Lakes region

“…Ultimately, within-stock variation in egg size may reflect multiple egg-size optima, whereby females that choose or influence the environment of their offspring can adjust egg size to maximize reproductive success in their unique spawning habitat. On the other hand, egg sizes are relatively uniform in stocks where mothers cannot influence the offspring environment, presumably because there is only one optimal offspring size Hendry et al, 2001;Hendry and Day, 2003; but see Lalonde, 2005;Hutchings, 2010, 2011).…”

Comparing resource exploitation and allocation of two closely related aphid parasitoids sharing the same host

“…For these parasitoids and many other insects, producing smaller eggs may thus be detrimental via an increased mortality and/or a decreased activity at the adult stage (Fox and Czesak 2000;Giron and Casas 2003;Boivin and Gauvin 2009). In parasitoids, plasticity in egg size or composition has rarely been investigated (Giron and Casas 2003;Bezemer et al 2005;Le Lann et al 2011b) and for koinobionts, the link between egg size and fitness of progeny has never been proven (Kraaijeveld and van Alphen 1994;Lalonde 2005). To our knowledge, this work is the first to report a change in egg size with age and/or food ingestion (i.e.…”