Intraspecific body size variability in a population of Billaea rhynchophorae (Blanchard) (Diptera: Tachinidae) parasitizing Rhynchophorus palmarum (Linnaeus) (Coleoptera: Curculionidae) in Brazil

Abstract

Background The black palm weevil, Rhynchophorus palmarum (Linnaeus, 1758) (Coleoptera: Curculionidae) is considered the most important palm pest in the Americas. In the State of Bahia, Brazil, it is parasitized by tachinid flies (Diptera: Tachinidae). During 2019–2020, larvae and pupae of R. palmarum were collected from African oil palms (Elaeis guineensis Jacq.) in the municipalities of Jaguaripe and Taperoá, Bahia State, Brazil. Puparia and adult tachinids of two apparent morphospecies, with considerable differences in body size, were obtained from the R. palmarum immatures, which led to initially assume that we had collected two different tachinid species. Results Morphological identification as well as COI gene sequencing showed that the two apparent morphospecies belong to a single taxonomic species, Billaea rhynchophorae (Blanchard, 1937) (Diptera: Tachinidae). Conclusions Occurrence of intraspecific size variability in B. rhynchophorae was reported, as well as performed the first genetic sequencing for this species. The reason of the size variation could not be determined but some possible causes and implications are discussed.