Mineral and natural films change the physical-chemical properties of grapes and modulate oviposition behaviour of Ceratitis capitata Wiedemann (Diptera: Tephritidae).

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann), is one of the main pests of fruit, worldwide, and the use of population suppression method with low environmental impact is an increasingly strong requirement of the consumer market. The aim of this study was to evaluate the effect of mineral and natural films on the physical-chemical properties of grapes (Vitis vinifera L.), cultivar Itália, and oviposition behaviour of C. capitata. Fruits were immersed in suspensions (100 and 200 g L-1) of mineral (kaolin Surround®WP, kaolin 607, kaolin 608, kaolin 611 and talc) and natural films (chitosan, cassava starch, potato starch and guar gum 5.0 g L-1) and distilled water (control). After drying, fruits were exposed to C. capitata pairs of males and females for 24 h in choice and non-choice tests; the number of punctures with and without eggs, eggs per fruit and behavioural response of fly to treated and untreated fruits were recorded. Results obtained in this study are promising, given the scientific evidence that films of mineral particles such as kaolin (Surround®, 607, 608 and 611) changed the firmness, luminosity, chroma and hue angle of grapes and reduced the oviposition of C. capitata. In addition, our results also showed that natural polymers do not deter C. capitata females, but rather seem to stimulate oviposition.

Genetic variability of conditioned probing responses to a fruit odor in Leptopilina boulardi (Hymenoptera: Eucoilidae), a Drosophila parasitoid.

The genetic variability of odor-conditioned probing behavior was investigated in a population of Leptopilina boulardi, a parasitoid of Drosophila larvae. Ovipositor probing is the final step of host location, leading to the discovery of host larvae. It can be triggered by an odor previously experienced during an oviposition as a result of associative learning. This study was based on the analysis of female probing performance over two generations of isofemale lines (using both mother-daughter regressions and one-way analysis of variance). Individual performances of the conditioned response to the odor were characterized by (1) the latency (i.e., the time elapsed between the onset of the odor delivery and the start of the probing response), (2) the duration of the first probing phase, and (3) the total probing duration. Results suggested that the variability of two characters, the latency and the duration of the first probing phase, were under a genetic control in the studied population. This work is the first contribution to quantify the genetic component of this variability.