Functional response in two laboratory population of Diachasmimorpha longicaudata

MARIANA M. VISCARRET; DIEGO F. SEGURA; HERNÁN M. FUNES; LEONELA Z. CARABAJAL PALADINO; SILVINA GOENAGA; JORGE L. CLADERA

Florida, EEUU

Congreso; 5th Meeting of the Working Group on Fruit Flies of the Western Hemisphere; 2004

The functional response of females from two laboratory population of Diachasmimorpha longicaudata (Hymenoptera: Braconidae) was compared. These two parasitoid strains are rearing on different strains of Ceratitis capitata (Diptera: Tephritidae), one on the genetic sexing strain CAST191 and the other on a wild-type strain.   Ceratitis capitata larvae (2nd-3rd stage) in numbers of 1, 10, 20, 30, 40, 50 or 60, were exposed to 4-6 days old D. longicaudata single females with previous experience. We recorded the numbers of emerged parasitoids and fruit flies, and of not emerged pupae. Ten replicates were run for each density, one of them was used to count the number of scars by larvae and the other was frozen at the pupae stage for future analysis.   The data showed a low proportion of larvae producing parasitoid at low densities (actually none at density 1). Larger proportion of parasitoid were obtained at intermediate densities of larvae (40:1 for the stains rearing on wild-type flies, 30:1 for the one rearing on CAST191, and somewhat lower values at densities of 50:1 and 60:1. No significant difference was found between parasitoids rearing on the two strains.   Preliminary analysis of the number of scars did not provide clear conclusions.   These results are discussed in the context of the observation by other authors. Further analysis will be required in order to clearly establish what is the type of functional response present here.