Preliminary evaluation of an artificial diet for the rearing of the hoverfly Allograpta exotica.

GRECO N; ROCCA M. ; DÍAZ LUCAS MF

Annapolis

Congreso; International Branch Virtual Symposium 2021; 2021

Entomological Society of America

Predatory hoverflies are relevant in agricultural systems because they provide two important ecosystem services. Adults are pollinators while larvae are natural enemies of pests. Artificial insect rearing is a useful tool both for research purposes and commercial mass-rearing. The larvae of most Allograpta species (Diptera: Syrphidae) are effective biocontrol agents, mainly aphids, and Allograpta exotica is abundant in several crops. We evaluated survival and duration of the larval instars of A. exotica larvae fed artificial diet, published for chrysopids. The experimental unit was a Petri dish, with 0.5 g of diet wrapped in Parafilm®. The treatments were one larva of: I) first instar (L1), II) second instar (L2), and III) third instar (L3). Survival was recorded daily, and the average duration of each instar (mean ± ES) was calculated. The larval survival percentage was higher for L3 (100%) than L2 (50%) and L1 (30%) (Z=-1.94; P=0.02; Z=-2.73; P=0.003; respectively). The duration of each instar was 3 ± 0.0, 2.5 ± 0.5 and 4.14 ± 0.14, for L1, L2 and L3 instars, respectively. These preliminary results suggest that this diet could be used for the rearing of A. exotica, mainly for L2 and L3 instars. The use of an easy to produce and low-cost food in predator mass rearing would allow to reduce the plant materials and prey colonies in the rearing system. However, it would be important to evaluate the effect that this artificial diet, given during the larval stage, would have on the fertility and survival of adults.