Modelling diapause termination and phenology of the Japanese beetle, Popillia japonica

Gianni Gilioli,Anna Simonetto,Andrea Battisti,Mariangela Ciampitti,Beniamino Cavagna,Michele Colturato,Nicola Mori,Paola Gervasio,Alessandro Bianchi,Giorgio Sperandio

doi:10.1007/s10340-021-01434-8

Abstract

We developed a mechanistic, stage-structured model simulating the phenology of Popillia japonica. The model simulates the influence of soil temperature on the larval diapause termination and on the development rate function of post-overwintering larvae and pupae. Model parameters are estimated based on literature evidence for pupae development and on a parameterisation process that allows estimating parameters for larval diapause termination and for the development rate function (and the related uncertainty) of post-overwintering larvae. Data used for model parameterisation and validation refer to time-series adult trap catches collected during the P. japonica monitoring programme performed by the Phytosanitary Service of Lombardy Region within the infested area in Lombardy (Italy) from 2015 to 2019. A total of 12 randomly selected locations are used to estimate biologically realistic model parameters (parameterisation dataset). We applied a Jackknife nonparametric resampling procedure on the parameterisation dataset to quantify uncertainty associated with parameters’ estimates. Parameterised model is then validated on time-series adult trap catches data referring to a different set of 12 randomly selected locations (validation dataset) surveyed in Lombardy. The model successfully predicted the beginning of adult emergence and the overall curve of adult emergence in the validation dataset. The model presented can support the definition of the best timing for the implementation of monitoring and control activities for the local and the area-wide management of P. japonica.

Highlights

The Japanese beetle (Popillia japonica) is an invasive and highly polyphagous pest belonging to the family of Scarabaeidae
Adult trap catches data collected from the 24 locations included in the present study show differences in the phenology and abundance of the species
The time of adult emergences is reported as ordinal day, which represents the day of the year ranging between 1 and 366

Summary

Introduction

The Japanese beetle (Popillia japonica) is an invasive and highly polyphagous pest belonging to the family of Scarabaeidae. Various aspects of the species life-history are influenced by temperature, including the emergence of adult individuals, mating, oviposition and larval development (Fleming 1972). Adults emerge in summer from May to July (Fleming 1972) and feed on the flowers and fruits of many host plants (Metcalf and Flint 1962; Potter and Held 2002; Klein 2008). Approaching late autumn, second and third instar larvae start moving deeper into the soil (at depths greater than 15 cm) to overwinter and avoid freezing temperature (Potter and Held 2002).

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Results

Conclusion