CRYOBIOLOGY OF THE FREEZE-TOLERANT GALL FLY EUROSTA-SOLIDAGINIS - OVERWINTERING ENERGETICS AND HEAT-SHOCK PROTEINS

The goldenrod gall fly Eurosta solidaginis (Diptera: Tephritidae) ranges from the southern U.S. northward into Canada. The larva overwinters within a ball gall on the stem of goldenrod Solidago spp. The galls often extend above the snowpack, exposing the larva to a wide range of environmental extremes in winter. This species has received extensive attention as a freeze-tolerant insect model. A seasonal study of the overwintering bioenergetics of an Ohio, USA, population revealed marked decreases in body weight, lipid and total caloric content in October and November when environmental temperatures were the highest. Overwintering larvae produce heat shock proteins in response to high-temperature exposure. However, unlike other insects E. solidaginis does not appear to synthesize heat shock proteins in response to low-temperature exposure.