Despite a growing interest in the evolutionary aspects of maternal effects, few studies have examined the genetic consequences of maternal effects associated with parental care, To begin to provide data on nonlaboratory or nondomestic animals. we compared the effect of presence and absence of parental care on phenotype expression of larval mass and development time at different life-history stages in the burying beetle Nicrophorus pustulatus. This beetle has facultative cared parents can feed their larvae through regurgitation or digested carrion or offspring can reed by themselves from previously prepared carrion. To investigate larval responses to these two levels of care, including estimates of additive genetic effects, maternal effects, and genotype-by-environment interactions, we used a half-sibling split-family breeding experiment-raising half of the offspring, of a family in the presence of their mother and the other hair without their mother present, Larvae reared with their mother present were on average headier and developed faster, although some of the difference in development decreased or were eliminated by the adult stage. These results suggest that presence or absence of post-hatching maternal care plays an important role in phenotype expression early in life, whereas later the phenotype of the offspring is determined mainly by the genotype and/or unshared environmental effects. Our study also permitted Lis to examine the differences in genetic effects between the two care environments. Heritabilities, maternal/common environment effect, and most genetic correlations did not differ between the care treatments. Genetic analyses revealed substantial additive genetic effects For development time but small effects for measures of body mass. Maternal Plus common environment effects were high for measure,, of mass hut low for development time. suggesting that indirect genetic effects or maternal and/or common environment are less important for the evolution of development time than for mass. Estimates of genetic correlations revealed a trade-off between the duration of the two development stages after the offspring left the carrion. There also a negative genetic correlation between the time spent on carrion and the mass at 72 h, when mothers usually feeding. The analysis of genotype-by-environment interactions indicates substantial among maternal families in response to care. Presence or absence of parental care may therefore contribute to the additive genetic variance through its interaction,with the maternal component of the additive genetic variance. The presence of this interaction further suggests that parent may vary in care strategies, with some parents dispersing after preparation of the carrion and some parents staving with the larvae. This interaction may help maintain genetic variation in growth, development time, and parental care behavior. Additional work is needed, however, to quantify indirect genetic effects, and genetic variation in parental care behavior itself.
