Dispersal–reproduction trade‐off in the leaf beetleGalerucella grisescens

Abstract

Dispersion-reproduction trade-offs are important to explore the evolutionary mechanism of dispersal strategies and the adaptive significance of dispersion in insects. In our previous study, variations in hindwing length were found in Japanese populations of the leaf beetle Galerucella grisescens (Joannis) (Coleoptera: Chrysomelidae). They were distinctly divided into either long-winged (LW) or short-winged (SW) morphs in the field. The LW morphs were distributed widely in Japan, whereas the SW morphs were found in restricted areas in Honshu, the main island of Japan. We examined the possible existence of trade-offs between dispersion and reproduction in G. grisescens by laboratory experiments. Larval duration and adult body size (head width) were not significantly different between LW and SW strains, but adult body weight was larger in some LW strains than in SW strains, most likely due to the size of hindwings and legs as well as to the development of flight muscles. Although the pre-oviposition period was not significantly different among strains, female longevity and fertility were significantly higher in SW than in LW strains. Long-winged individuals displayed flutter behaviours, suggesting their flight dispersal abilities, but SW individuals did not. Femurs of LW individuals were significantly longer on all legs compared to SW strains and the former walked faster than the latter. The present results indicate the presence of a dispersion-reproduction trade-off in G. grisescens, in which SW strains have advantages in reproductive abilities and LW strains in dispersal abilities.

A test of trade-offs in dispersal and reproduction within and between a sister species pair of specialist insect herbivores

“…Trade-offs between dispersal and reproduction are often found within wing-dimorphic insect species (Roff 1986;Guerra 2011), where ight-capable, long-winged 'macropterous' morphs and reduced-ight, short-winged 'brachypterous' morphs are each present within a species and can be expressed as plastic responses to uctuating environments (Zera and Rankin 1989;Carroll et al 2003;Nasu and Tokuda 2021). However, divergence in trade-offs between dispersal and reproduction among closely related species within a genus are less prevalent (Tigreros and Davidowitz 2019).…”

“…Hence, bothHood and Ott (2017) and the present study provide evidence that reproductive traits are highly adaptable phenotype under selection in this group of Belonocnema gall wasps. Since dispersal and reproduction often exhibit trade-offs either within species or among species across many study systems(Carroll et al 2003;Guerra 2011;King et al 2011;Nasu and Tokuda 2021), more studies should link changes in linear relationship among these life history traits to the variation of selection pressures each of these traits experience (e.g., populations at the range edge).We argue that B. fossoria individuals with higher reproductive output but lower ight capability may gain a tness advantage in the Q. geminata environment, leading to selection favoring the divergent phenotypes between B. fossoria and B. treatae. This is because B. fossoria's host plant, Q. geminata, is typically found as short shrubs no taller than 10 m in small clusters in sandy soil, whereas B. treatae's host plant, Q. virginiana, is a much taller tree species (with a mean height of ~ 21m) and has a patchier distribution (Cavender-Bares and Pahlich 2009).…”

Resource relocations in relation to dispersal in Tetranychus ludeni Zacher

“…Compared with residents, dispersers often have lower fecundity and higher mortality (Mole & Zera 1993;Bonte et al 2012;Khuhro et al 2014;Renault 2020;Nasu & Tokuda 2021), leading to slower population growth (Baguette & Schtickzelle 2006;Keenan & Cornell 2021). In addition, the cost of dispersal may increase with the distance a species moves, resulting in distance-specific resource trade-offs (Rousset & Gandon 2002;Baker & Rao 2004;Samietz & Köhler 2012;Serrano & Tella 2012), the magnitude of which can affect expansion speed.…”