A chemically-triggered transition from conflict to cooperation in burying beetles

Although interspecific competition has long been recognized as a major
driver of trait divergence and adaptive evolution, relatively little
effort has focused on how it influences the evolution of intraspecific
cooperation. Here we identify the mechanism by which the perceived
pressure of interspecific competition influences the transition from
intraspecific conflict to cooperation in a facultative cooperatively
breeding species, the Asian burying beetle Nicrophorus
nepalensis. We not only found that beetles are more cooperative at
carcasses when blowfly maggots have begun to digest the tissue, but that
this social cooperation appears to be triggered by a single chemical
cue—dimethyl disulfide (DMDS)—emitted from carcasses consumed by
blowflies, but not from control carcasses lacking blowflies. Our results
provide experimental evidence that interspecific competition promotes the
transition from intraspecific conflict to cooperation in N.
nepalensisvia a surprisingly simple social chemical cue that is a reliable
indicator of resource competition between species.