Do Termites Avoid Carcasses? Behavioral Responses Depend on the Nature of the Carcasses

Abstract

BackgroundUndertaking behavior is a significant adaptation to social life in enclosed nests. Workers are known to remove dead colony members from the nest. Such behavior prevents the spread of pathogens that may be detrimental to a colony. To date, little is known about the ethological aspects of how termites deal with carcasses.Methodology and Principal FindingsIn this study, we tested the responses to carcasses of four species from different subterranean termite taxa: Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe) (lower termites) and Microcerotermes crassus Snyder and Globitermes sulphureus Haviland (higher termites). We also used different types of carcasses (freshly killed, 1-, 3-, and 7-day-old, and oven-killed carcasses) and mutilated nestmates to investigate whether the termites exhibited any behavioral responses that were specific to carcasses in certain conditions. Some behavioral responses were performed specifically on certain types of carcasses or mutilated termites. C. formosanus and R. speratus exhibited the following behaviors: (1) the frequency and time spent in antennating, grooming, and carcass removal of freshly killed, 1-day-old, and oven-killed carcasses were high, but these behaviors decreased as the carcasses aged; (2) the termites repeatedly crawled under the aging carcass piles; and (3) only newly dead termites were consumed as a food source. In contrast, M. crassus and G. sulphureus workers performed relatively few behavioral acts. Our results cast a new light on the previous notion that termites are necrophobic in nature.ConclusionWe conclude that the behavioral response towards carcasses depends largely on the nature of the carcasses and termite species, and the response is more complex than was previously thought. Such behavioral responses likely are associated with the threat posed to the colony by the carcasses and the feeding habits and nesting ecology of a given species.

Corpse Management in Social Insects

“…Corpse removal (necrophoresis in a narrow sense) is prevalent in honey bees 6 and ants 5, 22, 34, although burial (covering the dead) 15 and cannibalism (intraspecific necrophagy) 35 were also documented in ants. In contrast, undertaking responses are more complex in termites than eusocial hymenopterans 7.…”

“…To maintain healthy colonies, eusocial hymenopterans (bees, wasps, ants) and isopterans (termites) have evolved sophisticated mechanisms to counter the threat of epidemic disease at both the individual and colony level, including active immune responses and behavioral adaptations 3, 4. Corpse management, also anthropomorphically known as undertaking behavior, is one of the most intriguing innate behaviors in social insects 5-7.…”

“…In species of the two extensively-studied eusocial lineages, Hymenoptera (ants, bees, and wasps) and Isoptera (termites), corpse management is distinctive and differs from other nest cleaning behaviors such as disposing of feces and decaying food remains 6, 12, 13. Facilitated with different behavioral repertoires (e.g., removal, burial, and cannibalism), honey bees, ants, and termites have evolved complex systems of corpse management dealing with corpses of different ages, origins, and infection status 7, 14-16. Although the specific components of corpse management are distinctly unique in various taxa of eusocial insects, the evolution of a complex strategy for dealing with the dead is a shared characteristic of eusociality.…”

“…To date, studies of undertaking behavior have been focused on three aspects: death recognition cue, behavioral process, and division of labor. Recently, there have been renewed interests in undertaking behavior in termites focusing on death cues and behavioral responses 7, 19-21. Despite studies for over 50 years, the genetic underpinning of undertaking behavior is still not well understood.…”

Mortality Patterns in <I>Coptotermes gestroi</I> (Blattodea: Rhinotermitidae) Following Horizontal Transfer of Nonrepellent and Repellent Insecticides: Effects of Donor:Recipient Ratio and Exposure Time

“…In contrast, Shelton et al (2005) observed a lack of transfer of permethrin among nestmates of R. flavipes in laboratory trials, as the repellent properties of pyrethroid on donor termites inhibited social interactions from healthy termites. The mortality of recipient workers in the current study might be associated with secondary contamination caused by the accumulation of donor carcasses and their associated fungus growth, carcass handling by healthy termites, or a crowding effect, as found for Reticulitermes (Neoh et al 2012b, Shelton 2012.…”