Ability of a Generalist Seed Beetle to Colonize an Exotic Host: Effects of Host Plant Origin and Oviposition Host

Abstract

The colonization of an exotic species by native herbivores is more likely to occur if that herbivore is a generalist. There is little information on the life-history mechanisms used by native generalist insects to colonize exotic hosts and how these mechanisms are affected by host properties. We examined the ability of the generalist seed beetle Stator limbatus Horn to colonize an exotic species. We compared its host preference, acceptability, performance, and egg size when ovipositing and developing on two native (Pithecellobium dulce (Roxb.) Benth and Senegalia riparia (Kunth)) and one exotic legume species (Leucaena leucocephala (Lam.)). We also analyzed the seed chemistry. We found that females recognize the exotic species as an unfavorable host for larval development and that they delayed oviposition and laid fewer and larger eggs on the exotic species than on the native species. Survivorship on the exotic host was 0%. Additionally, seeds of the native species contain five chemical compounds that are absent in the exotic species, and the exotic species contains three sterols, which are absent in the native legumes. Genetically based differences between beetles adapted to different hosts, plastic responses toward new hosts, and chemical differences among seeds are important in host colonization and recognition of the exotic host. In conclusion, the generalist nature of S. limbatus does not influence its ability to colonize L. leucocephala. Explanations for the colonization of exotic hosts by generalist native species and for the success of invasive species must be complemented with studies measuring local adaptation and plasticity.

Pesticide resistance in arthropods: Ecology matters too

“…The host plant community available for a herbivorous arthropod may also change due to plants' geographical expansion, and native arthropods will then encounter novel plant species that enter their geographical range either naturally or introduced by humans. While it may be challenging to incorporate new plants as hosts (e g. Amarillo‐Suárez et al, 2017), there is also evidence that arthropods could integrate non‐native plant species into their diet breadth (Andersen et al, 2019; Bezemer et al, 2014; Brown et al, 2017; Graves & Shapiro, 2003; Janz et al, 2001; Lakatos et al, 2016). One example is the aphid Myzus persicae which probably adapted to tobacco after its introduction to Europe in the 16th Century by overexpressing P450 genes to detoxify nicotine (Simon & Peccoud, 2018), a gene family that has been shown to be involved in pesticide resistance in arthropods (Feyereisen, 2006; Nauen et al, 2022; Box 2).…”