Winter warming effects on overwinter survival, energy use, and spring emergence of the bean leaf beetle Cerotoma trifurcata 2010 to 2013 [South-central Ontario, Canada]

The potential effects of warmer winters and fluctuating thermal regimes on overwintering bean leaf beetle (Cerotoma trifurcata) using field and laboratory experiments was assessed. The 3 year (Winter of 2010-2011, 2011-2012, and 2012-2013) field experiment involved three warming levels: heated ~4 degrees Celsius above ambient, unheated with snow cover left intact, and unheated with snow cover removed. Survival and date of emergence were examined in all years, and beetle lipid content was analyzed in one year to determine rates of energy use. The laboratory experiment assessed effects of frequency and duration of fluctuating thermal regimes on survival.