Fenoxycarb exposure disrupted the reproductive success of the amphipod Gammarus fossarum with limited effects on the lipid profile.

Hélène Arambourou,Emmanuelle Vulliet,Nicolas Delorme,Patrice Noury,Khedidja Abbaci,Gaëlle Daniele,Carlos Barata,Inmaculada Fuertes,Amitava Mukherjee

doi:10.1371/journal.pone.0196461

Abstract

Insect growth regulator insecticides mimic the action of hormones on the growth and development of insect pests. However, they can affect the development of non-target arthropods. In the present study, we tested the effects of the growth regulator insecticide fenoxycarb on several endpoints in the freshwater crustacean Gammarus fossarum (Amphipoda). Females carrying embryos in their open brood pouch were exposed to 50 μg L-1 fenoxycarb throughout the entire oogenesis (i.e. 21 days). After exposure, newborn individuals from exposed embryos were removed from the maternal open brood pouch for lipidomic analysis, while males were added to assess the reproductive success. After fertilization, the lipid profile, energy reserve content (lipids, proteins and glycogen), and activity of phenoloxidase − an enzyme involved in the immune response − were measured in females. No significant effect of fenoxycarb exposure was observed on the lipid profile of both newborn individuals and females, while reproductive success was severely impaired in exposed females. Particularly, precopulatory behavior was significantly reduced and fertilized eggs were unviable. This study highlighted the deleterious effects of the insect growth regulator fenoxycarb on gammarid reproduction, which could have severe repercussions on population dynamics.

Highlights

The reproductive success of G. fossarum was strongly affected by exposure to 50 μg L-1 of fenoxycarb, while both exposed newborn individuals and females did not exhibit any significant alteration of their lipid profiles
Precopulatory behavior has been shown to be severely altered by insecticide exposure [31,32]
Reproductive success, especially reproductive behavior, was severely impaired in females of G. fossarum exposed to fenoxycarb

Summary

Introduction

The use of growth regulator insecticides having juvenoid activity is increasing because they have a selective mode of action and some pests have developed resistance against classical neurotoxic insecticides [1]. They are used in agriculture for pest management [2], in public health for vector control [3] and in veterinary treatment to prevent pet infestation [4]. Juvenoid insecticides mimic the action of juvenoid hormones on the growth and development of insect pests.

Methods

Results

Discussion

Conclusion