Horizontal Transfer of Diatomaceous Earth and Botanical Insecticides in the Common Bed Bug, Cimex lectularius L.; Hemiptera: Cimicidae

Yasmin Akhtar,Murray B Isman,Joseph Clifton Dickens

doi:10.1371/journal.pone.0075626

Abstract

BackgroundHorizontal transfer of insecticide occurs when insects contact or ingest an insecticide, return to an aggregation or a nest, and transfer the insecticide to other conspecific insects through contact. This phenomenon has been reported in a number of insects including social insects, however it has not been reported in bed bugs. Since horizontal transfer can facilitate the spread of insecticide into hard to reach spaces, it could contribute greatly to the management of these public health pests.Methodology/ResultsTo demonstrate horizontal transfer of diatomaceous earth and botanical insecticides in C. lectularius, an exposed (donor) bed bug, following a 10-minute acquisition period, was placed with unexposed (recipient) bed bugs. Mortality data clearly demonstrates that diatomaceous earth (DE 51) was actively transferred from a single exposed bug to unexposed bugs in a concentration dependent manner. LC50 values varied from 24.4 mg at 48 h to 5.1 mg at 216 h when a single exposed bed bug was placed with 5 unexposed bed bugs. LT50 values also exhibited a concentration response. LT50 values varied from 1.8 days to 8.4 days when a ‘donor’ bug exposed to 20 and 5 mg of dust respectively was placed with 5 ‘recipient’ bugs. Dust was also actively transferred from adult bed bugs to the nymphs. In addition we observed horizontal transfer of botanical insecticides including neem, ryania, and rotenone to varying degrees.Conclusion/SignificanceOur data clearly demonstrate horizontal transfer of diatomaceous earth and botanical insecticides in the common bed bug, C. lectularius. Use of a fluorescent dust provided visual confirmation that contaminated bed bugs transfer dust to untreated bed bugs in harborage. This result is important because bedbugs live in hard-to-reach places and interaction between conspecifics can be exploited for delivery and dissemination of management products directed at this public health pest.

Highlights

Horizontal transfer of insecticides occurs through the transfer of the active ingredients among individuals within an insect population through contact
Since there are no reports on horizontal transfer of dusts or other insecticides in bed bugs, the main objective of our study was to investigate whether adults of C. lectularius exposed to diatomaceous earth and botanical insecticides could transfer them to unexposed members of a population
Our results have demonstrated that bed bugs contaminated with Diatomaceous earth (DE) dust or botanicals caused mortality in other bed bugs while sharing a harborage through contact

Summary

Introduction

Horizontal transfer of insecticides occurs through the transfer of the active ingredients among individuals within an insect population through contact. The phenomenon occurs when the most active members of a colony, often foraging adults, become exposed to an insecticide residue, which is subsequently transferred to unexposed members of the colony upon returning to the nest. Horizontal transfer of insecticide occurs when insects contact or ingest an insecticide, return to an aggregation or a nest, and transfer the insecticide to other conspecific insects through contact. This phenomenon has been reported in a number of insects including social insects, it has not been reported in bed bugs. Since horizontal transfer can facilitate the spread of insecticide into hard to reach spaces, it could contribute greatly to the management of these public health pests

Objectives

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Results

Conclusion