Genetic and maternal influences on life history plasticity in milkweed bugs (Oncopeltus): response to temperature

Abstract

This study was designed to examine life history flexibility arising from phenotypic plasticity in response to temperature and from maternal effects in response to reproductive diapause in a temperate zone population of the milkweek bug (Oncopeltus fasciatus). We employed a split‐family, first‐cousin, full‐sib design with siblings reared at different temperatures in order to quantify phenotypic plasticity, maternal effects, and variation for each. The following traits were analyzed: development time, age at first reproduction, longevity, early‐life fecundity, and wing length. We found both life history plasticity and maternal effects on life history traits which tend to enhance the colonizing ability of offspring born to mothers that have undergone reproductive diapause. We were unable to demonstrate additive genetic variation for plasticity for any of the traits, while for development time and wing length we found variation due to non‐additive genetic or common‐environmental sources. We were also unable to demonstrate additive genetic variation for maternal effects, although variation may exist at low levels that are difficult to detect using cousin‐families. The apparent lack of variation in this population would constrain evolution of life history flexibility even though considerable flexibility exists in the phenotype. Copyright © 1988, Wiley Blackwell. All rights reserved