Does sensory deception matter in eusocial obligate food robber systems? A study of Lestrimelitta and stingless bee hosts

Social parasites can break into their host colonies using sensory deception, force, or both. To evaluate the role of sensory deception in eusocial obligate food robbers, we studied the Mesoamerican stingless bee Lestrimelitta niitkib–host species system, including preferred and nonpreferred host species. The use of citral as a propaganda substance is documented in L. niitkib, but possible mechanisms used by individual scouts to overcome host species recognition have not been studied. We analysed the cuticular profiles of L. niitkib and host species, coupled with bioassays of time to aggression (latency) and included data on host species raid frequency. We found that L. niitkib has a simple, but not insignificant, cuticular profile. Generally, L. niitkib cuticular profiles were similar to (but did not mimic) profiles of its preferred host species and differed from profiles of nonpreferred hosts. As expected, latency generally fitted a recognition system based on the degree of similarity between the cleptobiontʹs cuticular label and the host species template, with chemically similar species reacting slower and chemically distant species reacting rapidly to L. niitkib. There was a positive correlation between raid ratio and latency, indicating that the speed of detection and aggression towards L. niitkib scouts could influence host species selection. Cuticular profile similarity of individual L. niitkib scouts to host species may help L. niitkib scouts evade recognition and attacks from guards. In a further step, unnoticed L. niitkib scouts could successfully recruit nestmates to mass-raid host species colonies. The fact that L. niitkib can also plunder aggressive species, suggests that obligate cleptobiosis within its narrow biological niche could be characterized by flexibility in invasion strategies to allow exploiting a broad range of host species and be successful over evolutionary times.