A Comparison of the Vertical Transmission of High- and Low-Virulence Nucleopolyhedrovirus Strains in Lymantria Dispar L.

Yuriy B Akhanaev,Darya A Lebedeva,Vyacheslav V Martemyanov,Irina A Belousova,Sergey V Pavlushin

doi:10.3390/insects11070455

Abstract

Baculoviruses can persist in insect host organisms after infection and may be vertically transmitted to the next generation, in which they may be reactivated. The goal of the present study was to compare the efficiency of the vertical transmission of high- and low-virulence strains and the subsequent reactivation of Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV) in the offspring of Lymantria dispar L. adults who survived after viral infection. As a result of parental infection, the fecundity of survived females, pupae weight, and fertility were significantly different compared to the untreated insects. However, differences in these parameters between high- and low-virulence strains were not observed. The prevalence of virus strains in the offspring measured by quantitative polymerase chain reaction also did not differ. When the larvae reached the fourth instar, they were starved to activate the vertically transmitted virus. The frequency of virus activation in the experiment was not dependent on the virulence of the virus strains. These results are helpful for understanding the strategy of virus survival in nature and for the selection of the most effective strains with transgenerational effects in the years following pest treatment.

Highlights

The causes of cycles in insect pest populations have long been a major focus in ecological research [1,2]
The stock was estimated on the prevalence of covert Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV) infection in the egg masses of host populations by quantitative PCR (qPCR)
Host survival was severely reduced by baculovirus infection (χ2 = 140.1, df = 1, p < 0.0001)

Summary

Introduction

The causes of cycles in insect pest populations have long been a major focus in ecological research [1,2]. Among the many factors affecting the cycles of insect pest populations, baculoviruses occupy an important role [3,4]. Baculoviruses are important natural enemies of many lepidopteran species and have been developed as biological control agents for a range of pests in agriculture and forestry [5,6,7]. They are generally highly pathogenic and infect host larvae during feeding [8]. Virus-induced mortality is observed at the larval and pupal stages and is never observed at the adult stage

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