Local adaptations and phenotypic plasticity may render gypsy moth and nun moth future pests in northern European boreal forests

Abstract

Phenotypic plasticity and local adaptations are important factors in predicting range expansions and shifts of pest insects in a changing climate. We reared two lepidopteran forest pests, Lymantria monacha (Linnaeus) and Lymantria dispar (Linnaeus), at three climatically different field sites from central Germany to northern Finland to investigate differences among populations in plasticity in the timing of pupation and adult emergence (measured as cumulative temperature sums, degree-days >5 °C), pupal mass, and duration of the pupal period. We also compared the phenologies of continental and boreal L. monacha populations feeding on Scots pine (Pinus sylvestris L.) to reveal possible local adaptations. Lymantria dispar was reared on different host plants, Quercus robur L., Betula pendula Roth, and Betula pubescens ssp. czerepanovii (Orl.) Hämet-Ahti, to evaluate the possibilities of a range expansion northwards. There was stronger indication of adaptive phenotypic plasticity, which enables species to cope with changing environmental conditions, in continental L. dispar and boreal L. monacha populations than in the continental L. monacha population. Differences between boreal and continental L. monacha populations may denote adaptation to local conditions. All three host plants used for L. dispar proved suitable for the species, revealing that host plant availability would not limit its range expansion in northern Europe.

Jack, master or both? The invasive ladybird Harmonia axyridis performs better than a native coccinellid despite divergent trait plasticity

“…Previous studies on life-history traits have found mixed results regarding consistent plastic responses of traits in invasive insects as fecundity, offspring survival and developmental time to temperature (e.g. Kingsolver et al 2007;Terblanche et al 2010;Ferrer et al 2014;Fält-Nardmann et al 2018). Invasive H. axyridis performed better over a broader range of conditions than C. lunata for the majority of life-history traits (with the exception of hatching success and developmental time) but we found no notable differences in plasticity of these traits between species.…”

Cold hardiness of Lymantria monacha and L. dispar (Lepidoptera: Erebidae) eggs to extreme winter temperatures: implications for predicting climate change impacts

“…It is possible that adaptive phenotypic plasticity, i.e. the ability of the same genotype to produce different phenotypes under different conditions, plays a role in the cold hardiness of L. monacha; however, this cannot be assessed based on our experiment, as the Finnish and German L. monacha were reared in the same conditions (but see Fält-Nardmann et al, 2017).…”

Evolutionary genomics of gypsy moth populations sampled along a latitudinal gradient

“…Controlled laboratory experiments, moreover, have shown that gypsy moths reared at higher temperatures experience reduced pupal mass and increased development times (Logan et al, ; Thompson et al, ), both of which are likely to lower fitness (Calvo & Molina, ; Honěk, ; Myers, Malakar, & Cory, ). Low temperatures have also been shown to have negative consequences for development in European gypsy moth, with some populations displaying patterns of adaptive variation (Fält‐Nardmann, Klemola, et al, ; Fält‐Nardmann, Ruohomäki, Tikkanen, & Neuvonen, ). In general, these traits are also heritable, with those related to development time and pupal mass having heritabilities varying from 0.181 to 0.703 (Janković‐Tomanić & Lazarević, ; Lazarević, Nenadović, Janković‐Tomanić, & Milanović, ; Lazarević, Perić‐Mataruga, Ivanović, & Anđelković, ; Lazarević, Perić‐Mataruga, Stojković, & Tucić, ; Lazarević, Peric‐Mataruga, & Tucić, ; Páez, Fleming‐Davies, & Dwyer, ).…”