Analysis of dispersal and survival of adult Anastrepha fraterculus fed on different adult diets

UTGES, M.E.; DE LA VEGA, M.; MENDOZA, M.; OVIEDO, A.; ABRAHAM, S.; VERA, M. T.; VILARDI, J.

Pereybere, Isla Mauritius

Workshop; Final RCM on Improving Sterile Male Performance in Fruit flies SIT; 2009

IAEA

Laboratory studies on A. fraterculus in Argentina (Utgés & Vilardi, 2006), and on A. ludens in Mexico (Hernández et al 2006), indicate that under food deprivation conditions, post-teneral diets rich in carbohydrates resulted in greater male survival. On the other hand, protein rich diets resulted in faster sexual maturation and better mating performance, but survival was adversely affected. In the present work we conducted an experiment of survival and dispersal of A. fraterculus in the field by applying a central point release approach to test the effects of different adult diet regime. Emerged adults were fed for 4 days under three different dietary regimes: in the first one (diet S) flies were fed only sugar, in the second treatment (C) they were fed on an enriched diet with sugar, hydrolyzed yeast, hydrolyzed corn, and vitamins, and in the third one (SC) flies were fed with sugar for the first two days and with the enriched diet during the third and fourth days. In order to allow identification, flies fed on different diets were marked with different fluorescent dyes. On the morning of day 5, similar numbers of flies fed with different diets were released in a 10 ha. lemon orchard near San Miguel de Tucuman city (Argentina). One day after release, 89 McPhail® traps, baited with protein hydrolysate (Susbin®) were set up concentrically around the release point. Traps were serviced daily, up to 7 days. Captured flies were taken to the laboratory for color and sex identification. Four replicates were conducted in from November 2008 to March 2009. The number of released flies per treatment and repeat ranged from 6000 to 10000. The ratio between emerged males and females (~4:5) differed statistically from the expected (1:1) (chisq= 11.94, P= 0.0005). Sex ratio of captured flies was not statistically different from that of emerged flies, suggesting that survival in the field is similar for both sexes. The number of females captured did not differed significantly among treatments in any of the repeats. In the case of males the number of individuals fed on S and SC was significantly higher than those fed on C, but significant heterogeneity was observed between repeats. The plots of the proportion of trapped individuals through time showed similar trends for all three treatments giving similar estimates of life expectancies, however, survival measures in small field cages suggested that flies fed the first 2 days on S and the following 2 days with C have the longest survival. Dispersal analysis indicated that females tend to disperse further than males (anova F=11.54, P= 0.0007) whereas no significant differences were detected among treatments. The patterns of spatial distribution of flies fed on different adult diets were also similar. The results obtained so far suggest that the combination of sugar during the first days and protein enriched diet for the following two days would combine the benefits of sugar-only diets on survival and the known effects of protein rich diets on fly maturation