Unusual host selection in Amblycerus dispar larvae (Coleoptera: Chrysomelidae: Bruchinae) and its potential impact on stored almonds (Prunus dulcis)

Abstract

We present the first report of Amblycerus dispar (Sharp) attacking stored almonds [Prunus dulcis (Mill.) D. A. Webb] in Argentina. A summarized diagnosis, illustrations, and photographs of the adult and mature larva are provided to facilitate identification. We performed species distribution models for A. dispar and its main host plant Geoffroea decorticans (Gillies ex Hook. & Arn.) Burkart. We include A. dispar into a previous morphological character matrix and conduct a phylogenetic analysis to infer its phylogenetic position. The evolution of host plant associations of the genus Amblycerus is herein re-analyzed. A. dispar and its main host shows high suitability areas especially in central-west Argentina and Chile, whereas for the USA, high suitability areas were found for the south-western which include the area of almond production in this country. Although the presence of A. dispar in the USA region is very unlikely, we recommend some awareness as other bruchines are present in the area. Although A. dispar is unlikely to become an economically important risk, monitoring for early detection is recommended to avoid productivity loss, especially when the native host is nearby cultivated areas. A. dispar is hypothesized to be the sister species of A. schwarzi Kingsolver. The colonization of a Rosaceae species is a novelty for this genus, being host shifts known as an important factor affecting both natural and agricultural systems.