EXPOSURE TO THE ESSENTIAL OIL OF SCHINUS POLYGAMA INCREASES THE SEXUAL SIGNALLING OF CERATITIS CAPITATA STERILE MALES

JOFRÉ-BARUD, F.; RUIZ, M. J; GÓMEZ, M. P..; SEGURA, D. F.; VERA M. T.; LÓPEZ, M. L.

Congreso; 5th Congress of the Latin American Association of Chemical Ecology; 2018

Volatile exposure of phytochemicals has been shown to increase male sexual competitiveness in some fruit flies. Such improvement might be associated with an increment in sexual signalling. In previous studies, we observed that mating success of Ceratitis capitata males exposed to the essential oil (EO) of Schinus polygama (Anacardiaceae) is equal or even greater than the achieved by males exposed to ginger root oil (GRO), an essential oil used in some mass rearing facilities of Ceratitis capitata that implement the Sterile Insect Technique (SIT). In the present study, we evaluated the effort in sexual signalling performed by sterile males exposed massively to GRO or to the EO of S. polygama. C. capitata males from the strain tsl Vienna 7 were placed inside plastic boxes (60 cm x 40 cm x 32 cm) to hold mature pupae and newly emerged adults before its release for a SIT program (24,000 flies per box arranged in 4 paper bags holding 6000 flies each one). One day prior to adults release, 400 mL of GRO or S. polygama EO were applied in paper filter disks (10 cm diam.) at the bottom of a Petri plate over the floor of the plastic box. After the exposure, 5 males were placed inside one glass jar (180 mL capacity) covered with voile. Each treatment was evaluated in 10 replicates and the experiment was repeated three times (days) with independent batch of flies. Exposures were carried out in independent rooms at 16:8 h light-darkness at 20 ºC. The control treatment without EO volatile exposure ran simultaneously in a plastic box without exposure. The number of males performing some of the following behaviours was recorded: wing funning (F), anal pouch exposure (AE) and F+AE. Data were registered at intervals of 15 min from 9:00 to 10:00 AM. Results showed that AE behaviour was increased in males exposed to S. polygama EO (p=0.004). Unexposed males displayed the least frequency of AE behaviour and, GRO treatment exerted an intermediate increase in the frequency of this behaviour. Therefore, it is likely that the improvement in mating success of males exposed to S. polygama EO is explained by the fact that females respond to the calling of males exhibiting a greater effort in sexual signalling.