Cannibalism associated with artificial wounds on the bodies of Reticulitermes speratus workers and soldiers (Isoptera: Rhinotermitidae)

Abstract

We investigated the cannibalism and its association with cannibalistic grooming in Reticulitermes speratus (Kolbe), first by observing workers’ cannibalistic behavior against workers artificially wounded on different body parts. Almost all the wounded thoraces and abdomina were eaten, while in some of the abdomen-wounded individuals, nestmates’ cannibalism extended from the abdomen to the thorax, and thorax was cannibalistically attacked in all the abdomen-wounded individuals. In thorax-wounded individuals cannibalistic damage mostly extended from the thorax to the abdomen to a lesser degree. In the assessments of the frequencies and durations of the cannibalistic groomings toward different body parts, the wounded individuals, upon being groomed, occasionally exhibited vibrational behavior, and its frequencies upon the groomings toward wounded body parts were significantly higher than those toward non-wounded body parts. Vibration significantly reduced the duration of cannibalistic grooming on the wounded head and abdomen, while it reduced the grooming frequency and did not reduce the duration of grooming on wounded thorax. These results suggest that the vibration serves as a vital sign or death-negative factor in death recognition. A feeding experiment with workers’ cuticular hydrocarbon extract showed that it did not promote cannibalistic behavior. A feeding experiment with filter papers impregnated with different body part extracts showed that all the extracts exhibited phagostimulant activity, with workers’ body extracts resulting in significantly higher quantity of consumption than in soldiers’ except abdomen. Further assay revealed a stronger activity of labial gland compared to the labial gland-removed thorax, suggesting the key role of labial gland in cannibalism.