Numerous studies have shown that parental care can affect expression of traits in offspring. From the point of view of offspring, parental care is an environmental factor like food or air temperature. For the parents, however, parental care is a trait like any other trait; it is determined by parental genes and the environment to which the parent is exposed. Through their effects on the offspring environment, both parental genes and the parental environment can affect offspring traits such as growth and developmental time. These effects of parental genes and environment on trait expression in offspring are called indirect genetic effects and indirect environmental effects, respectively. The indirect genetic effects are of special interest, because they can influence rate and direction of response of traits to natural selection. This study will investigate how parental care affects trait evolution. The specific objectives are to 1) determine the amount of variation in progeny traits that is due to indirect genetic effects in an insect species with parental care, 2) investigate whether the influence of indirect genetic effects depends on the developmental stage in which the trait is expressed as has been observed in many mammals, and 3) examine the relative influence of indirect genetic effects in individuals reared with and without parental care. The results of this research will significantly increase our understanding of trait evolution in animals with parental care. The comparison between an insect with parental care with mammals and birds will give us insights about the generality of the evolutionary models including parental effects. These models have been developed primarily based on observations in domesticated mammals. The comparison of parental effects in animals reared with and without parental care will provide invaluable information about how parental care affects trait evolution.
