Studying genetic population structure to shed light on the demographic explosion of the rare species Barbitistes vicetinus (Orthoptera, Tettigoniidae)

Abstract

Insect outbreaks usually involve important ecological and economic consequences for agriculture and forestry. The short-winged bush-cricket Barbitistes vicetinus Galvagni & Fontana, 1993 is a recently described species that was considered rare until ten years ago, when unexpected population outbreaks causing severe defoliations across forests and crops were observed in north-eastern Italy. A genetic approach was used to analyse the origin of outbreak populations. The analysis of two mitochondrial regions (Cytochrome Oxidase I and II and 12S rRNA-Control Region) of 130 samples from the two disjunct ranges (Euganean and Berici Hills) showed high values of haplotype diversity and revealed a high geographical structure among populations of the two ranges. The high genetic variability observed supports the native origin of this species. In addition, results suggest that unexpected outbreaks are not a consequence of a single or few pestiferous haplotypes but rather the source of outbreaks are local populations which have experienced an increase in each area. The recent outbreaks have probably appeared independently of the genetic haplotypes whereas environmental conditions could have affected the outbreak populations. These findings contribute to a growing understanding of the status and evolutionary history of the pest that would be useful for developing and implementing biological control strategies for example by maximizing efforts to locate native natural enemies.

Strong genetic differentiation between fragmented alpine bush‐cricket populations demands preservation of evolutionary significant units

“…The Bayesian tree search was performed with the Yule model. Due to the unavailability of molecular data about the species of Anonconotus , we decided to infer the DTE using the empirical mutation ranging from 2% to 3% (mean 2.5%, equal to 1.25 × 10 −8 substitutions/site/year) according to the literature (Allegrucci et al, 2009; Brower, 1994; Chang et al, 2020; Martinez‐Sañudo et al, 2021; Papadopoulou et al, 2010; Rogers, 1995). To assess the convergence across independent runs, we conducted the RLC_HKY analyses twice, each one set for 50 million generations and sampling trees every 1000 generations with a final burn‐in of 25%.…”

Increasing temperatures affect multiyear life cycle of the outbreak bush‐cricket Barbitistes vicetinus (Orthoptera, Tettigoniidae)

“…Compared to other tettigoniids, oviposition occurs very early in June (Cavaletto et al, 2018). In spite of the presence of recent studies about population genetics, ecology and life history traits of B. vicetinus (Magello et al, 2003;Cavaletto et al, 2015Cavaletto et al, , 2018Cavaletto et al, , 2019Ortis et al, 2020;Martinez et al, 2021), there is a lack of data about the factors that influence egg development and survival, hampering the development of effective control strategies. In this study, we want to test if summer temperature affects embryonic diapause and how winter temperatures affect egg survival.…”