INCREASE OF PARASITISM RATES OF DIACHASMIMORPHA LONGICAUDATA REARING ON X-IRRADIATED CERATITIS CAPITATA LARVAE.

CONTE, CLAUDIA L.; FERNÁNDEZ SALINAS, MARIA; LANZAVECCHIA, SILVIA B.; VISCARRET, MARIANA M.; SEGURA, DIEGO F; CLADERA, JORGE L

Congreso; VIII International Symposium on Fruit Flies of Economic Importance; 2010

Background: Control strategies including the sterile insect technique (SIT) and biological control using parasitoids are currently applied against Ceratitis capitata. In Argentina, the larval parasitoid Diachasmimorpha longicaudata is currently being evaluated as candidate for biological control. Parasitism rate is one of the most important parameter to determine productivity and efficacy of parasitoids as biocontrol agents. The study of host-parasitoid interactions provides useful information to optimize the massive rearing of parasitoids. This interaction involves the immune response which is triggered after the female parasitoid oviposits on the host larvae. Previous studies have shown that the exposure to radiation suppresses host immune system responses in other insect species. Our objective was to study parasitism rates by D. longicaudata on irradiated larvae of C. capitata. Methods: Late second stage-early third stage of C. capitata larvae were treated with different X-ray doses (20, 40 and 80 Gy) prior to exposure to D. longicaudata females. Seven replicates were tested for each dose. Parasitized larvae were kept at controlled condition of humidity and temperature until emergence. Non-irradiated larvae were used as a control. Parasitism rates were calculated from the number of emerged parasitoids for each X-ray dose. The parasitism rate was corrected taking into account the number of non-emerged parasitoids. A one-way ANOVA was performed. When the test was significant, post-hoc pair-wise comparisons were performed using Tukey`s HSD (Honestly Significant Difference). Results: Parasitism rates of larvae exposed to 20 G and 40 Gy and non-irradiated larvae showed no significant differences. Larvae irradiated with 80 Gy showed the highest rate of parasitism which significantly differed from those obtained with non-irradiated larvae (p