Developmental Isolation and Subsequent Adult Behavior of Drosophila paulistorum. VI. Quantitative Variation in Cuticular Hydrocarbons

Abstract

Our previous studies have demonstrated that long-term chemical contact with heterospecifics during development minimized unproductive heterospecific matings among the six Drosophila paulistorum semispecies. When socially isolated from conspecifics, discrimination significantly decreased so that more ultimately unproductive heterospecific matings occurred. Such results suggest that learning and social experiences play roles in mate recognition, using chemical information. In investigations into the development of discriminatory behavior in D. paulistorum, social experiences influence the production of cuticular hydrocarbons in both sexes among the six different semispecies of D. paulistorum. Produced by both sexes, 2-methyl triacontane has been detected from egg stages on, gradually increasing with age. However, 11-docosenyl acetate, a male pheromone, was not produced until early adult stages. There were consistent significant differences in quantities and ratios of each of these hydrocarbons among the six semispecies, contributing to their reproductive isolation. Furthermore, we found significant quantitative differences in hydrocarbons between socially isolated flies and communally raised ones: Socially isolated flies produced significantly greater quantities of hydrocarbons than communally raised flies, consistent with previous behavioral data, as isolated flies court more vigorously and often.

Learning decreases heterospecific courtship and mating in fruit flies

“…were inconclusive owing to a variety of weaknesses including small sample sizes, different treatments conducted over days or months in a system notorious for huge time effects, pseudoreplication, and confounds created by testing only a non-random sample of the flies (e.g. Mayr & Dobzhansky 1945;O'Hare et al 1976;Pruzan 1976;Kim et al 2004).…”

Sexual isolation between North American and Bogota strains of Drosophila pseudoobscura

“…Following the procedure of Kim and Ehrman (1998), a 7-day-old male and female pair was introduced without anesthetization into a modified Elens and Wattiaux (1964) chamber in a no choice situation. The bottom of the observation chamber was coated with a thin layer of fly instant medium.…”

Drosophila adult and larval pheromones modulate larval food choice

“…Memory persistence through the complete metamorphosis remains an enigma in holometabolous insects (such as Drosophila), because a large part of the nervous system is reorganized during this process. Studies involving mixed Drosophila culture (of two strains, sub-species or species) showed that pre-imaginal exposure to homo-versus heterospecific (or homo-versus heterotypic) chemical cues affect adult sexual behaviour and mate discrimination [24,50,51]. However, the identity of these cues currently remains unknown and neither H3B2 nor phenol seems sufficient to induce food-choice conditioning in either Drosophila species.…”

“…These molecules can influence a variety of adult behaviours; namely aggregation, courtship, mating and aggression [19][20][21][22]. Pre-imaginal exposure to specific food components mixed, or not, with pheromones can also affect subsequent adult behaviour in Drosophila mojavensis, Drosophila arizonae [23] and Drosophila paulistorum [24], but the identity of compounds involved remains unknown.…”