Effect of Wolbachia Infection and Adult Food on the Sexual Signaling of Males of the Mediterranean Fruit Fly Ceratitis capitata

Abstract

Sexual signaling is a fundamental component of sexual behavior of Ceratitis capitata that highly determines males' mating success. Nutritional status and age are dominant factors known to affect males' signaling performance and define the female decision to accept a male as a sexual partner. Wolbachia pipientis, a widespread endosymbiotic bacterium of insects and other arthropods, exerts several biological effects on its hosts. However, the effects of Wolbachia infection on the sexual behavior of medfly and the interaction between Wolbachia infection and adult food remain unexplored. This study was conducted to determine the effects of Wolbachia on sexual signaling of protein-fed and protein-deprived males. Our findings demonstrate that: (a) Wolbachia infection reduced male sexual signaling rates in both food regimes; (b) the negative effect of Wolbachia infection was more pronounced on protein-fed than protein-deprived males, and it was higher at younger ages, indicating that the bacterium regulates male sexual maturity; (c) Wolbachia infection alters the daily pattern of sexual signaling; and (d) protein deprivation bears significant descent on sexual signaling frequency of the uninfected males, whereas no difference was observed for the Wolbachia-infected males. The impact of our findings on the implementation of Incompatible Insect Technique (IIT) or the combined SIT/IIT towards controlling insect pests is discussed.

Keywords: Incompatible Insect Technique; Sterile Insect Technique; endosymbiotic bacteria; medfly; pheromone; sexual behavior.

Figure 1

Age-specific sexual signaling of males uninfected and infected with the bacterium Wolbachia fed on (a) yeast plus sugar and (b) sugar only. On each day of age, observations were conducted hourly from 07:00 to 21:00 h in 10 cages (replicates) containing 10 males each. Values on the y-axis are mean numbers (±SE) of males signaling per cage per hour observation.

Figure 2

Daily rhythm of sexual signaling on adult day 5 of Ceratitis capitata males uninfected and infected with Wolbachia fed on a (a) yeast plus sugar (YS) and (b) sugar only (S) diet. The values on the y-axis are mean numbers (±SE) of males signaling per cage per hour observation. The grey and black bars represent the uninfected and infected line, respectively.