One mechanism that can help organisms cope with climate change or other novel environments is phenotypic plasticity, the ability for one genotype to produce different phenotypes across different environments. Phenotypic plasticity can be grouped into two different types: within-generational plasticity (WGP) and trans-generational plasticity (TGP). WGP results from an individual’s own environment, while TGP results from parental environment. When both types of plasticity are present for a trait, their effects can be additive or interactive. Interactive effects can result in phenotypes more extreme than expected, so investigating whether interactive effects occur within a system is necessary to understand how populations will react under different conditions. In this study, invasive New Zealand mud snails (Potamopyrgus antipodarum) were used to investigate whether 1) WGP and TGP are present, and 2) if both are present, whether the effects are additive or interactive for several life history traits. P. antipodarum were randomly placed into either low (5 ppt) or high salinity (12 ppt) conditions, as were their offspring. Growth and reproductive measurements were taken on the offspring. Logistic growth curves were fitted for each treatment and used to calculate several growth parameters, and total reproduction and reproductive rate where recorded for snails that reproduced.
Results/Conclusions
Preliminary results suggest that WGP is present for total reproduction and reproductive rate, TGP is present for asymptotic size, and both WGP and TGP are present for intrinsic growth rate and time to maturity. For the traits that had both WGP and TGP, no interactive effects were found. As described earlier, interactive effects could lead to more extreme phenotypes than predicted under additive models, so it is important to test whether WGP and TGP interact within a system to understand how that population may respond across environments. As the effects of WGP and TGP appear to be additive for the life history traits where both types of plasticity are present, this could suggest that the mechanisms for WGP and TGP differ, as shared mechanisms are expected to result in interactive effects. In summary, environmental shifts can occur through various methods, including range expansions, invasions, and climate shifts. Understanding how WGP and TGP can interact is essential for predicting and managing responses of populations to environmental shifts.