Be the first to arrive: Anastrepha fraterculus strategy to overcome competitive advantages of Ceratitis capitata.

LIENDO, M. CLARA; A PARREÑO; CLADERA, J; , MT VERA; DF SEGURA

Congreso; 8th Meeting of the Working Group on Fruit Flies from the Western Hemisphere; 2012

Ceratitis capitata and Anastrepha fraterculus are two major fruit pest in Argentina. It is common to find larvae of both species infesting the same fruit, creating conditions for the occurrence of competitive interactions. Previous studies suggest that C. capitata females prefer ripe fruit for oviposition whereas A. fraterculus females show a tendency to lay eggs on unripe fruit. In turn, the duration of the larval stage is longer for A. fraterculus than for C. capitata. Here we compared the effects of competition between larvae of both species when A. fraterculus has as temporal advantage compared to C. capitata. Newly hatched larvae of both species were transferred into a container with a fixed amount of larval diet. We transferred A. fraterculus larvae at the load capacity of the container and then we added larvae of C. capitata with a delay of 0 to 4 days. We measured pupal recovery and weight, larva to pupa and pupa to adult developmental times and adult emergence. We found that when larvae of both species were transferred the same day, A. fraterculus larvae suffer a decrease in pupal weight and in pupal recovery and an increase in larva to pupa developmental time. A difference of 3 days between both species was enough to reverse this situation. In this case, C. capitata larvae that were transferred 3 days after A. fraterculus suffer negative effects in pupal weight and pupal recovery. Our results suggest that the oviposition preference of A. fraterculus females for unripe fruit acts as a mechanism by which this species reduces the negative effect of interspecific competition, allowing the two species to coexist in nature.