Comparative Study of the Phenotypic Structure and Photoperiodic Responses of Female Asian Ladybirds Harmonia axyridis (Pallas) (Coleoptera, Coccinellidae) from Moscow, Belgorod, and Sochi

N A Belyakova,S Ya Reznik,A N Ovchinnikov,O S Bezman-Moseyko

doi:10.1134/s0013873821060014

Abstract

Insect invasions are often accompanied by changes in the phenotypic structure of the populations and in the photoperiodic responses that regulate seasonal cycles. The Asian ladybird Harmonia axyridis has been recently discovered in Krasnodar Territory, from whence it is now gradually colonizing Central Russia. Our comparative study of individuals collected in 2020 in Sochi, Belgorod Province, and Moscow Province shows that interpopulation differences in their phenotypic structure are nonsignificant. The proportion of the light morph succinea is 77–83%; the proportion of the most common dark morph, spectabilis, is 13–20%. Laboratory experiments show that females from all the studied populations exhibit only a weak photoperiodic response. Comparative analysis reveals that females from the more northerly Moscow and Belgorod populations have a somewhat greater tendency to diapause and slightly delay reproductive maturation.

Highlights

The Asian ladybird Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is an aggressive invasive aphidophagous species of beetle that is native to East Asia but to date discovered in many countries of Europe, North and South America, and Africa (Roy and Wajnberg, 2008; Lombaert et al, 2010; Brown et al, 2011; Roy et al, 2016)
The seasonal cycles of insects are adapted to the local climate, and so dispersion outside the native range is accompanied by the corresponding changes in the main parameters of the photoperiodic response (Saulich, 1999)
The broadscale invasion of the Asian ladybird from East Asia to Southern, Western, and Central Europe was accompanied not by adjustment but by attenuation of the photoperiodic response so that the main role in the control of the seasonal cycle was transferred to diet-induced diapause (Reznik et al, 2015)

Summary

Introduction

The Asian ladybird Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is an aggressive invasive aphidophagous species of beetle that is native to East Asia but to date discovered in many countries of Europe, North and South America, and Africa (Roy and Wajnberg, 2008; Lombaert et al, 2010; Brown et al, 2011; Roy et al, 2016). The seasonal cycles of insects are adapted to the local climate, and so dispersion outside the native range is accompanied by the corresponding changes in the main parameters of the photoperiodic response (Saulich, 1999). The broadscale invasion of the Asian ladybird from East Asia to Southern, Western, and Central Europe was accompanied not by adjustment but by attenuation of the photoperiodic response so that the main role in the control of the seasonal cycle was transferred to diet-induced diapause (Reznik et al, 2015). The objective of this work was to answer two questions: (1) does the phenotypic structure of the populations vary and (2) does the tendency for weaker photoperiodic sensitivity persist as H. axyridis is further expanding its distribution in the European part of Russia?

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