Meeting Abstract
71.2 Thursday, Jan. 6 Seasonal cues alter the temperature-size relationship in an ectotherm CLEMMENSEN, S.F.*; CERVONI, G.E.; HAHN, D.A.; University of Tennessee, Knoxville; University of Florida; University of Florida sclemmen@utk.edu
Developmental temperatures can have dramatic effects on body size in ectotherms. Most ectotherms decrease in size as temperature increases, the temperature-size rule, but some show the opposite pattern. Despite the substantial effect of temperature on size, the effects of other seasonal changes, such as photoperiod, on temperature-size relationships are poorly understood. We use the moth Helicoverpa zea (corn earworm) to determine the effects of seasonal dormancy programming (pupal diapause) on the temperature-size relationship, lipid storage, and resource utilization. H. zea increased in both lipid and lean mass with increasing temperature from 16oC to 20oC in both diapause-destined and non-diapause photoperiod treatments. The scaling relationship between lean mass and temperature did not differ between diapausing and non-diapausing pupae, but diapause-destined pupae were fatter across all temperatures, showing that seasonal photoperiodic cues can alter temperature-size relationships. Across temperatures, diapause-destined larvae increased food consumption, and diapause-destined males increased digestive efficiency as temperature increased, supporting greater pupal lipid mass. We conclude that the effect of temperature on body size can be modified by other seasonal cues, and that considering specific sub-components of mass (e.g. lipid vs. lean mass) provides needed insight into how seasonal cues alter temperature-size relationships.
