Chapter 13 - Impact of Life-History Evolution on Population Dynamics: Predicting the Presence of Maternal Effects

Abstract

This chapter discusses the importance of population quality parameters. Herbivore population growth has been described by the change in number over time. For most young, the earliest environmental experiences are a function of parental quality, a fact easily imagined for humans and mammals in general, but less obvious for fish, insects, rotifers, and the like, where parental care is more subtle. At present, relatively little is known about the occurrence and expression of maternal effects in phytophagous insects. An effort was made to use a phylogenetic diversity of representatives from this group. Of the 92 moth species ultimately included, 42% are microlepidopterans and the rest are macrolepidopterans. In total, 21 families and 78 genera are represented. Two species from the same genus were permitted only if the two differed in dynamics class or exhibited significant differences in life history. Based on the character state of life-history traits V3 through V7, a maternal effects score was calculated for each species. Based on the criteria used for the ME score, there is a low probability that maternal effects are involved in the fluctuations of those outbreak species with low ME scores. Several other researchers have noted an association between outbreak dynamics and some of same life-history traits that is used here in calculating the ME score. Interestingly, the first extensive study of maternal effects in insects came from an outbreak species with gregarious habits and hatch at budbreak, called the western tent caterpillar. Geographic variation in population dynamics is known for several species.