Demographic histories of three predatory lady beetles reveal complex patterns of diversity and population size change in the United States

Predatory lady beetles (Coccinellidae)contribute to biological control of agri- cultural pests,however,multiple species frequently compete for similar resources in the same environment.Numerous studies have examined ecological interactions among the native North American convergent lady beetle (Hippodamia convergens)and two intro- duced species,the seven-spotted lady beetle (Coccinella septempunctata)and the Asian lady beetle (Harmonia axyridis),in agricultural fields and described multiyear population dynamics.However,the evolutionary dynamics of these interacting species of predatory beetles are uncharacterized.We utilize publicly available multilocus genotype data from geographically disjunct populations of these three species to estimate demography across North American populations.Coalescent analyses reveal (1)a recent (4-5years)decline (>12 fold)in microsatellite effective population size ofH.convergens,while expanding (mutation scaled growth rate in 1/u generations =2910,SD =362)over evolutionary time scales,(2)a massive (>150 fold),and very recent,effective population size decline in Ha. axyridis,and (3)population size growth (mutation scaled growth rate =997,SD =60)over recent and evolutionary time scales in C.septempunctata.Although these estimates are based on genetic data with different mutation rates and patterns of inheritance (mitochondrial versus nuclear),these dynamic and differing population size histories are striking. Further studies of the interactions of these predatory lady beetles in the field are thus warranted to explore the consequences of population size change and biological control activities for evolutionary trajectories in North America.

Extreme developmental temperatures result in morphological abnormalities in painted turtles(Chrysemys picta):a climate change perspective

Increases in extreme environmental events are predicted to be major results of ongoing global climate change and may impact the persistence of species.We examined the effects of heat and cold waves during embryonic development of painted turtles(Chrysemys picta)in natural nests on the occurrence of abnormal shell morphologies in hatchlings.We found that nests exposed to extreme hot temperatures for>60 h produced more hatchlings with abnormalities than nests exposed to extreme hot temperatures for shorter periods,regardless of whether or not nesting females displayed abnormal morphologies.We observed no effect of extreme cold nest temperatures on the occurrence of hatchlings with abnormalities.Moreover,the frequency of nesting females with abnormal shell morphologies was approximately 2-fold lower than that of their offspring,suggesting that such abnormalities are negatively correlated with survival and fitness.Female turtles could potentially buffer their offspring from extreme heat by altering aspects of nesting behavior,such as choosing shadier nesting sites.We addressed this hypothesis by examining the effects of shade cover on extreme nest temperatures and the occurrence of hatchling abnormalities.While shade cover was negatively correlated with the occurrence of extreme hot nest temperatures,it was not significantly correlated with abnormalities.Therefore,female choice of shade cover does not appear to be a viable target for selection to reduce hatchling abnormalities.Our results suggest that increases in the frequency and intensity of heat waves associated with climate change might perturb developmental programs and thereby reduce the fitness of entire cohorts of turtles.