Phoretic specialization on insect herbivores facilitates mite transportation to host plants

Abstract

Phoresy, the use of another organism for dispersal, is one of the most intriguing commensalistic interactions. The selection of a correct host is fundamental for phoretic organisms to ensure arrival to suitable habitats and to encounter potential mates. This study focuses on a group of phoretic mites in the genus Lasioseius (Acari: Blattisociidae).In La Selva Biological Station, a tropical wet forest in Costa Rica, Lasioseius mites feed on nematodes inside the scrolls formed by the young leaves of their hosts, plants in the order Zingiberales. When leaves expand and unfurl, mites disperse to another rolled leaf by clinging onto 'rolled-leaf beetles', a group of insect herbivores specialized on Zingiberales (genera Cephaloleia and Chelobasis; Coleoptera: Chrysomelidae).In this study, we determined whether Lasioseius mites associated with Cephaloleia belti Baly are specialized on this beetle species as a phoretic host. Mites may also be attracted to Chelobasis perplexa Baly, sharing the same host plant. Another possibility is that Lasioseius mites are opportunistic generalists and attach to rolled-leaf beetle species (e.g., Cephaloleia dorsalis Baly) that never share host plants with either C. belti or Ch. perplexa. In a laboratory setting, we tested whether mites preferred scents from and/or attached to particular beetle species. Scent attraction experiments showed that Lasioseius mites collected from C. belti were attracted to scents from C. belti and Ch. perplexa, but were not attracted to scents from C. dorsalis. Mites collected from C. belti attached to both C. belti and Ch. perplexa, but never to C. dorsalis. In conclusion, Lasioseius mites are not strict specialists, but are able to detect and attach to beetle species that inhabit their host plant.

Novel insights into insect chemical communication – an introduction

“…For instance, mites of the genus Lasioseius who feed on nematodes inside leaf scrolls of Zingiberales plants require phoretic assistance for their dispersal by rolled‐leaf beetles. Bizzarri et al (2022) revealed an interesting olfactory mechanism underlying this specific occurrence of phoresy. They determined that the mites are specifically attracted to scents of rolled‐leaf beetle species sharing the same Zingerales host plants with them, but not to the scent of another rolled‐leaf beetle species occurring on Zingerales plants where the mites do not naturally feed.…”