Phoretic Relationships of the Blister Beetle Meloe (Meloe) Strigulosus Mannerheim (Coleoptera: Meloidae) from a Coastal Dune Habitat in Oregon

ABSTRACT The larval instars of the genus Meloe L. are known to develop on provisions and immature stages of various species of ground-nesting bees. The first instar of Meloe, commonly known as a triungulin, attains its food source through phoresy on adult bees. In most species, the triungulins quest on flowers and attach to visiting bees. It has long been known that triungulins also attach to a variety of pilose flower visitors such as Diptera that do not serve as hosts. The fate of triungulins attaching to non-host visitors has been questioned and considered by some to be dead-end behavior. In this study of Meloe strigulosus Mannerheim in a coastal dune habitat we provide the first direct evidence that attachment to non-host insects can result in flower to flower dispersal and thus is not necessarily a mortality factor. In addition, we show that non-host attachments, largely on species of Tachinidae, are relatively common and constitute a significant fraction of the total triungulin load carried by flower visitors. A survey of variation in the COI mitochondrial gene of M. strigulosus throughout our study area reveals four haplotypes; their distribution also provides limited evidence for within habitat dispersal prior to final host attachment.