Diel and Circadian Patterns of Locomotor Activity in the Adults of Diamondback Moth (Plutella xylostella).

Danfeng Wang,Guang Yang,Wenfeng Chen

doi:10.3390/insects12080727

Danfeng Wang, Guang Yang + Show 1 more

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https://doi.org/10.3390/insects12080727

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Abstract

The Diamondback Moth (Plutella xylostella) is a highly destructive lepidopteran pest of cruciferous crops. However, there still is relatively little known about the locomotor activities of diel and the circadian patterns in P. xylostella. Here, we present an analysis of the diel locomotion of P. xylostella under several laboratory settings. We established a system for measuring the individual locomotor activities of P. xylostella and found that both males and females showed a nocturnal pattern of activity under 26 or 20 °C LD conditions, with activity peaking immediately after lights off and quickly declining after lights on. In addition, we showed that it is difficult to assess the free-running circadian rhythms of P. xylostella under 26 °C DD conditions. However, we found that males showed a higher power, rhythm index (RI) and rhythmic ratio than females under 20 °C DD conditions, which indicated that males in low-temperature conditions are much more suitable to study the free-running circadian rhythms of P. xylostella. The findings of this study will help us to have a better understanding of the diel activity of P. xylostella and may provide a foundation for the development of an effective pest management strategy.

Highlights

Circadian rhythms are found in most species as the earth rotates around its axis every twenty-four hours
The circadian rhythms of adult lepidopteran insects have specific characteristics, in which the butterfly species are active during the day, and many moths are active at night [4]
Female moths produce and release pheromones at specific times of the day, which is synchronized with the rhythm of male moths; those are sensitive to pheromones [8]

Summary

Introduction

Circadian rhythms are found in most species as the earth rotates around its axis every twenty-four hours. The circadian rhythms control various physiological activities of lepidopteran insects. The circadian rhythms of adult lepidopteran insects have specific characteristics, in which the butterfly species are active during the day, and many moths are active at night [4]. The male gypsy moth (Lymantria dispar) exhibits a bimodal rhythm of locomotion and pheromone response, with one peak during the day and one peak at night [5]. This periodic change is affected by the endogenous circadian oscillator. Adult emergence and adult activity showed prominent circadian rhythms in the Mediterranean meal moth (Ephestia kuehniella) [7]. The phototransduction and circadian rhythm synchronization play a key role in the signal transduction mechanism of lepidopteran treetop disease caused by baculovirus [9]

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