Climate change alters the emergence date and range of Coccinellidae

Coccinellids are biological control agents of aphids on crops and therefore provide important ecosystem services to agriculture. A growing body of evidence shows that greater species diversity increases ecosystem function. For coccinellids, each species differs in their level of suppression on alternative insect prey and in their responses to changing environments. A decrease in diversity of coccinellids could reduce their effectiveness as ecosystem service providers in agricultural landscapes.

Native coccinellid species are declining, potentially due to climate change. Historical studies of other insects have shown a strong link between earlier spring emergence and warming climate. Coccinellids overwinter at the soil layer and may be influenced by decreasing periods of snow cover, thereby emerging later due to less insulation from the cold. I propose to test the following hypothesis to explain shifts in range and emergence times of coccinellids: Climate change has altered emergence times and range of coccinellid species through its effects on temperature and precipitation patterns.

Using the WorldClim database of bioclimatic variables and maximum entropy models we found that coccinellid ranges have shifted northwest and will continue to shift this direction under projected warming scenarios. This relationship is primarily driven by yearly temperature and precipitation patterns. Additionally, coccinellid species are emerging later in the spring potentially due to multiple factors related to climate change. The results will have implications for understanding how climate change influences the distribution and abundance of coccinellids in the agroecosystems.