Live Drosophila melanogaster Larvae Deter Oviposition by Drosophila suzukii

Abstract

The worldwide invasive insect pest, Drosophila suzukii Matsumura (spotted-wing Drosophila), lays eggs in soft and stone fruit before harvest. Hatched larvae cause fruit collapse and significant economic losses. Current control methods rely primarily on foliar insecticide applications, which are not sustainable long-term solutions due to regulatory restrictions and the risk of insecticide resistance developing. We showed before that D. suzukii were deterred from laying eggs on artificial media previously visited by its sister species—Drosophila melanogaster. In the current study, laboratory choice test experiments were conducted to identify which D. melanogaster life stage (eggs, larvae, or adult) deterred D. suzukii oviposition. We demonstrated that the presence of live D. melanogaster larvae on the egg-laying media consistently deterred D. suzukii oviposition. Drosophila melanogaster cuticular hydrocarbons (CHCs) were examined as candidate for the oviposition deterrent. CHCs of larval and adult D. melanogaster and D. suzukii were analyzed. In both species, the composition of the CHCs of larvae was similar to that of adults, although quantities present were much lower. Furthermore, the CHC profiles of the two species were markedly different. However, when assayed as deterrents in the laboratory choice test experiment, CHC extracts from D. melanogaster did not deter oviposition by D. suzukii.

Factors influencing oviposition behaviour of the invasive pest, Drosophila suzukii, derived from interactions with other Drosophila species: potential applications for control

“…Previous visitation on a food source by other Drosophila species, such as D. melanogaster or Drosophila lutescens (Malloch) prior to the introduction of D. suzukii have consistently led to fewer eggs laid by D. suzukii compared to egg laying on control media not exposed to non‐ D. suzukii species 46,47 . Comparable results were shown by Kienzle and Rohlfs where D. suzukii deposited significantly fewer eggs on blueberries previously oviposited on by D. melanogaster or wounded, indicating the presence of heterospecific cues by non‐ D. suzukii Drosophila species, compared to intact and untouched blueberries that had never been visited by any flies 48 .…”

“…The role of CHCs in interspecific interactions between D. suzukii and other Drosophila species is an area worthy of further investigation. A recent paper showed that presence of live D. melanogaster larvae led to reduced egg laying by D. suzukii but there was no evidence for the involvement of CHCs in this 47 …”

“…A recent paper showed that presence of live D. melanogaster larvae led to reduced egg laying by D. suzukii but there was no evidence for the involvement of CHCs in this. 47 The widely studied male D. melanogaster sex pheromone, cis-11-vaccenyl acetate (cVA) is not a CHC but has multiple roles including promoting the aggregation of conspecifics, 107 increasing mating acceptance by females, 108 suppressing courtship by other males, 109,110 and increasing aggression between conspecific males. 111 Perfuming male D. suzukii with cVA disrupted mating 112 which indicated that D. suzukii detect and respond to cVA, even though D. suzukii does not produce it.…”

“…114 The prospect of identifying, synthesising, and utilising CHCs derived from other Drosophila species to deter oviposition by D. suzukii have been suggested but not fully explored to date. 46,47,52,53 Drosophila can detect CHCs and sex pheromone such as cVA from their conspecifics and those of other species resulting in behavioural changes. CHCs from adult Drosophila simulans and Drosophila buzzatii (Patterson and Wheeler) repelled larvae of D. simulans from a food source.…”

“…The identification of behaviour‐altering Drosophila CHCs can be utilised in developing a push–pull based strategy to protect crops from D. suzukii but effective formulation and field application of this still needs further study 114 . The prospect of identifying, synthesising, and utilising CHCs derived from other Drosophila species to deter oviposition by D. suzukii have been suggested but not fully explored to date 46,47,52,53 …”