Host Plant and Antibiotic Effects on Scent Bouquet Composition of Anastrepha ludens and Anastrepha obliqua Calling Males, Two Polyphagous Tephritid Pests.

Martín Aluja,Larissa Guillén,Carlos Pascacio-Villafán,Alma Altúzar-Molina,Erick Enciso,Gabriela Cabagne

doi:10.3390/insects11050309

Abstract

In insects, the quality of sex pheromones plays a critical role in mating success and can be determined by the ability of larvae/adults to accrue chemical precursors. We tested the host-quality-effect hypothesis by analyzing the chemical composition of scent bouquets emitted by calling males of two polyphagous tephritid species (Anastrepha ludens and A. obliqua) that originated from 13 fruit species representing diverse plant families. In A. ludens, we worked with an ancestral host (Rutaceae), nine exotic ones (Rutaceae, Anacardiaceae, Rosaceae, Solanaceae, Lythraceae), and two species never attacked in nature but that represent candidates for host-range expansion (Solanaceae, Myrtaceae). In A. obliqua, we tested an ancestral, a native, and an exotic host (Anacardiaceae), one occasional (Myrtaceae), and one fruit never attacked in nature (Solanaceae). We identified a core scent bouquet and significant variation in the bouquet’s composition depending on the fruit the larvae developed in. We also tested the possible microbial role on the scent bouquet by treating adults with antibiotics, finding a significant effect on quantity but not composition. We dwell on plasticity to partially explain our results and discuss the influence hosts could have on male competitiveness driven by variations in scent bouquet composition and how this could impact insect sterile technique programs.

Highlights

In insects, mating success is often based on the ability to attract the opposite sex through the production of sex pheromones
We discovered that the scent bouquet of males originating from ancestral hosts (C. edulis and S. mombin in A. ludens and A. obliqua, respectively) contained the least number of components and that males originating from the most “novel” hosts, produced the richest scent bouquets, some with compounds never reported before, such as β-santalene, cyclopentanecarboxylic acid, 4-isopropylidene-2-vinyl, methyl ester, cis, β-sesquiphellandrene, bicyclo[5.2.0]nonane, 4-methylene-2,8,8-trimethyl-2-vinyl, p-cymen-7-ol, and trans-sesquisabinene hydrate for A. ludens (Supplementary Table S2), and tricyclo[3.1.0.0(2,4)]hexane, 3,6-diethyl-3,6-dimethyl, trans and p-cymen-7-ol for A. obliqua (Supplementary Table S2)
We suggest possible synthesis routes of certain scent bouquet compounds and their possible relationship with bacteria as there is the possibility of a mixed strategy in which flies developed endogenous synthesis routes encoded by specific genes related to certain compounds over evolutionary time, and on the other hand, they could rely on bacteria for the synthesis of the remaining compounds found in the effluvia of sexually-mature calling males (Supplementary Figure S1)

Summary

Introduction

In insects, mating success is often based on the ability to attract the opposite sex through the production of sex pheromones. (Lepidoptera: Bombycidae), Berger [6] on Trichoplusia ni Hübner (Lepidoptera: Noctuidae), Silverstein et al [7] on Ips confusus (LeConte) (Coleoptera: Curculionidae), and the seminal work on pheromone evolution in moths by Roelofs and Brown [8], thousands of publications have been produced and summarized in several review articles and book chapters [9,10,11,12] Because they are so critical for mating, the question of whether pheromones should largely remain invariant and not be affected by larval or adult diet has been debated for years, largely based on work.

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Conclusion