PARENT SESSION
Poster Session #3: Invertebrate Ecology.
Monday, August 5. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

Effect of larval size on overwinter survival and emerging adult size in a burying beetle.

Smith, Rosemary^*,1,2, ¹ Idaho State University, Pocatello, Idaho² Rocky Mountain Biological Laboratory, Crested Butte, Colorado, smitrose@isu.edu

ABSTRACT- Body size may influence both adult fecundity and the probability of survival through each life stage. Previous studies of the burying beetle (Nicrophorus, Coleoptera: Silphidae) have revealed both reproductive advantages to larger adults and the important role of parental care in determining larval size and number. In this study I measure the effect of size on survival over the winter period, and the correlation between larval size and the size of emerging adults. I collected data from 22 groups of 20 to 25 larvae sorted by size and overwintered outside under natural conditions in Colorado, USA. There was a significant positive correlation between larval size and adult size at emergence and a significant effect of size on overwinter survival. Data from two years yielded the following mean survival rates among size cohorts: small, 47.3 + 0.1%; medium, 73.2 + 0.7%, and large 85.7 + 0.1%. These values were used to predict adult emergence from separate broods containing larvae of known size. There was a significant positive correlation between predicted and actual emergence numbers. These results indicate that selection for large body size may result from an overwinter survival advantage and not just reproductive success. I demonstrate the implications of this result for models of parental care strategies as well as models of population dynamics.

KEY WORDS: body size, mortality, population dynamics, overwinter