Effect of rearing Cactoblastis cactorum on an artificial diet on the behaviour of Apanteles opuntiarum

VARONE, LAURA; MENGONI GOÑALONS, CAROLINA; FALTLHAUSER, ANA C.; GUALA, MARIEL E.; WOLAVER, DANIELLE; SRIVASTAVA, MRITTUNJAI; HIGHT, STEPHEN D.

JOURNAL OF APPLIED ENTOMOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2020 vol. 144 p. 278 - 286

0931-2048

Cactoblastis cactorum?s unintended arrival to Florida and its expansion in North America represents a threat to Opuntia-based agriculture and natural ecosystems in USA and Mexico. Apanteles opuntiarum attacks C. cactorum and has potentiality as a biocontrol agent due to its specificity, wide distribution and occurrence. Laboratory rearing methods utilizing excised cladodes for C. cactorum as host larvae of A. opuntiarum were developed, but need a continuous supply of cactus with a risk of microorganisms compromising the rearing. For parasitoids, host associated olfactory cues are the most important signals leading to host location, including odor of host metabolic sub products like feces, and chemicals emitted by the attacked plant. Little attention has been paid to behavioral differences of parasitoids in the presence of hosts reared on artificial diet, so the objectives of the present work were to determine the effect of the meridic diet for C. cactorum on parasitoid ability and behavior, and to determine if prior experience influences the response of A. opuntiarum to hosts. Parasitism rates and sex ratio were evaluated using cladodes or meridic diet as larvae food source. Behavioral experiments also evaluated the effect of prior experience (larvae or frass from larvae fed on cactus or diet) on host searching, encounter, and attack. Parasitism behavior of A. opuntiarum was negatively affected by the use of meridic diet to feed host larvae. The most influential factor that elicited excitatory behavioral responses was the type of substrate used, not the prior experience. However, a slight effect was observed due to the previous encounter with host frass, indicating a relevant stimulus for host location and acceptance. For laboratory mass rearing procedures of A. opuntiarum, we recommend adding frass from cactus fed larvae and a piece of cactus during parasitoid mating to maximize parasitism rates and percentage of female offspring.