Maternal effects, paternal effects, and their interactions in the freshwater snail Physa acuta.

Individuals exposed to predation risk can produce offspring with altered phenotypes. Most work on predation-induced parental effects has focused on maternal effects or on generalized parental effects where both parents are exposed to risk. We conducted an experiment to measure and compare maternal and paternal effects on offspring phenotypes and test for interactions in those effects. We exposed 82 snails from 22 lines to control or predator cues and created line dyads with the four possible mating pairings of control and predator cue exposed individuals. We measured the resulting body masses, shell masses, shell shapes, and anti-predator behaviors of the offspring. We found some evidence that offspring were larger and heavier when the mother was exposed to predation cues, but that this effect was negated when the father was also exposed. The mass of offspring shells relative to their total mass was unaffected by parental treatments. Shell shape was marginally affected by maternal treatment, but not paternal treatment. Behavioral responses to cues were not affected by maternal or paternal treatments. Our results suggest potential conflict between male and female parental effects and highlight the importance of examining the interactions of maternal and paternal effects.

Contributions of evolutionary anthropology to understanding climate-induced human migration.

Humans are able to thrive in a multitude of ecological and social environments, including varied environments over an individual lifetime. Migration-leaving one place of residence for another-is a central feature of many people's life histories, and environmental change goes hand-in-hand with migration, both in terms of cause and consequence. Climate change has amplified this connection between environment and migration, with the potential to profoundly impact millions of lives. Although climate-induced migration has been at the forefront of other disciplines in the social sciences, evolutionary anthropologists (EAs) have given it little attention. In this paper we draw upon existing literature and contribute our EA perspective to present a framework for analyzing climate-induced migration that utilizes theoretical approaches from a variety of social science disciplines. We focus on three overlapping dimensions-time, space, and severity-relevant to understanding the impact of climate change on human migration. We apply this framework to case studies from North America of people impacted by climate change and extreme weather events, including hurricanes, droughts, rising sea-levels, and wildfires. We also consider how access to both economic and social resources influence decisions regarding migration. Research focused on climate-induced human migration can benefit equally from the addition of EA perspectives and a more interdisciplinary theoretical approach.