EUROPEAN JOURNAL OF ENTOMOLOGY

Eur. J. Entomol. 98 (3): 277-282, 2001 | DOI: 10.14411/eje.2001.045

Large larvae of a flush-feeding moth (Epirrita autumnata, Lepidoptera: Geometridae) are not at a higher risk of parasitism: implications for the moth's life-history

Tiit TEDER^1,2,*, Toomas TAMMARU^1,3

¹ Institute of Zoology and Hydrobiology, Vanemuise 46, Tartu University, 51014 Tartu, Estonia

² Section of Ecology, Department of Biology, University of Turku, FIN-20014 Turku, Finland

³ Institute of Zoology and Botany, Riia 181, 51014 Tartu, Estonia

The effect of larval body size of Epirrita autumnata (Lepidoptera, Geometridae) on the risk of parasitism was studied in a field experiment. The experiment involved three pairwise exposures of different larval instars to parasitoids. Three hymenopteran species were responsible for most of the parasitism. Parasitism risk was found to be host-instar independent. This result was consistent across parasitoid species and experiments. The results suggest that host use by larval parasitoids cannot constrain selection for larger body size in E. autumnata. However, high mortality due to parasitism may select for a short developmental period (the slow-growth/high-mortality hypothesis), and smaller body sizes as a by-product. A strong selective effect of parasitism on the timing of larval development in E. autumnata is also unlikely. The larger was the host, the larger was the adult size of the parasitoid and the shorter its development time (for one species). We suggest that the lack of a preference-performance linkage in the system studied may be related to the time stress associated with the short phenological window of host vulnerability.

Keywords: Body size, parasitism risk, parasitoids, phenology, preference-performance linkage, life-history, Epirrita autumnata, Geometridae

Received: November 16, 2000; Revised: May 18, 2001; Accepted: June 21, 2001; Published: October 31, 2001  Show citation