Resilience of breeding Coccotrypes dactyliperda Fabricius, 1801 (Coleoptera: Curculionidae: Scolytinae) to ingestion by vertebrates

Abstract

Volant and terrestrial predators consume a wide range of palm drupes, some of which may be infested by spermatophagus beetles. Field observations suggest that the larvae of some beetle species survive the passage through the gastrointestinal tract. To assess the resilience of the date stone beetle, Coccotrypes dactyliperda Fabricius, 1801 (Coleoptera: Curculionidae: Scolytinae) to ingestion by vertebrates, specimens reared from infested Phoenix canariensis (Chabaud, 1882) (Arecales: Arecaceae) seeds were exposed in vitro to simulated gastric and intestinal fluids in a laboratory setting at Charles Sturt University (Albury, Australia) in 2018. The observed mortality among beetles protected in their galleries inside the seeds was low (11-24%). The continued breeding success was affected by numerous beetles abandoning the seeds after immersion. Total mortality occurred among unprotected beetles exposed for 12 h or longer. This study demonstrates that as mortality of adult beetles inside ingested seeds is very low, vertebrate vectors may aid in the medium- to long-distance dispersal of the species.