Changes in maternal investment in eggs can affect population dynamics

Abstract

The way that mothers provision their offspring can have important consequences for their offspring's performance throughout life. Models suggest that maternally induced variation in life histories may have large population dynamical effects, even perhaps driving cycles such as those seen in forest Lepidoptera. The evidence for large maternal influences on population dynamics is unconvincing, principally because of the difficulty of conducting experiments at both the individual and population level. In the soil mite, Sancassania berlesei, we show that there is a trade-off between a female's fecundity and the per-egg provisioning of protein. The mother's position on this trade-off depends on her current food availability and her age. Populations initiated with 250 eggs of different mean sizes showed significant differences in the population dynamics, converging only after three generations. Differences in the growth, maturation and fecundity of the initial cohort caused differences in the competitive environment for the next generation, which, in turn, created differences in their growth and reproduction. Maternal effects in one generation can therefore lead to population dynamical consequences over many generations. Where animals live in environments that are temporally variable, we conjecture that maternal effects could result in long-term dynamical effects.

Watching sexy displays improves hatching success and offspring growth through maternal allocation

“…Our data suggest that using artificial insemination in such programmes can reduce maternal allocation, thereby decreasing both the number of offspring produced and the future survival of the offspring in the absence of stimulation of females by displaying males. Without female stimulation, artificial insemination is expected to have negative effects on population dynamics, and therefore on population viability (Benton et al 2005), compared with natural reproduction. However, as suggested by our findings, high levels of maternal allocation can be maintained if artificial insemination is coupled to an appropriate stimulation of the breeding females.…”

Evidence for harvest-induced maternal influences on the reproductive rates of fish populations

“…Such an effect of parental quality on population dynamics has been demonstrated convincingly in soil mites (Benton et al 2005), but empirical evidence from other taxa is both limited and inconsistent (e.g. Erelli & Elkinton 2000;Banks & Powell 2004).…”

Food-supplementing parents reduces their sons' song repertoire size

“…When this is the case, the reproduction and survival of individuals reflect not only current environmental conditions, but also the environmental conditions experienced by their progenitors (reviews in Mousseau & Fox 1998;Lindströ m 1999;Metcalfe & Monaghan 2001), which can significantly affect population dynamics (Lindströ m 1999;Beckerman et al 2002;Benton et al 2005). Population models incorporating intergenerational effects typically assume there is a positive relationship between the parental environment and offspring quality (Ginsburg & Taneyhill 1994).…”