Thermal Transgenerational Plasticity and Its Effect on Competitive Ability and Consumer-Resource Dynamics in a Population of Daphnia ambigua

Abstract

Global temperature increases are predicted to quicken in pace this century, and with them so will the likely impact on natural populations. The extent to which organisms will be able to keep pace with and adapt to these environmental changes is an unanswered question. It has been demonstrated that changing environments can induce changes in phenotypes that persist across generations. TGP may be an important means for populations to cope with climate change stress, but our understanding of these interactions is incomplete. Prior work showed that Daphnia program their offspring for faster development when reared under cooler temperatures. Here I tested the impact of thermal TGP in development on population dynamics and competitive interactions in a species of zooplankton (Daphnia ambigua) from a lake in Connecticut. I found that populations whose parents were reared at cool temperatures had greater rates of population increase when their offspring were transferred to a warmer temperature compared with treatments that experienced consistently warm conditions. This link between parental rearing temperature and rates of population growth are thus likely due to divergent transgenerational effects of temperature on the expression of life history traits. Though, this link between transgenerational responses and population dynamics were much weaker (and non-significant) when the populations were reared in larger mesocosms. My findings call for more research into the relationship between TGP and population dynamics and community interactions.