Olfactory eavesdropping between two competing stingless bee species

• Published in: Behavioral ecology and sociobiology 2011-04, Vol.65 (4), p.763-774
• Main Authors: Lichtenberg, Elinor M, Hrncir, Michael, Turatti, Izabel C, Nieh, James C
• Format: Article
• Language: English
• Subjects: Animal behavior; Animal communication; Animal Ecology; Animal populations; Bees; Behavioral Sciences; Biomedical and Life Sciences; Cephalic labial glands; Chemosensory perception; decision making; Dominance; Eavesdropping; Esters; foraging; Foraging behavior; Gas chromatography; Insect behavior; Insect colonies; Insect nests; Interceptive eavesdropping; Life Sciences; Mass spectrometry; Odors; Original Paper; Pheromone glands; Pheromones; Social information; Social insects; Stingless bees; Trigona; Trigona spinipes; Trophic levels; Zoology
• ISSN: 0340-5443; 1432-0762
• DOI: 10.1007/s00265-010-1080-3

Foragers can improve search efficiency, and ultimately fitness, by using social information: cues and signals produced by other animals that indicate food location or quality. Social information use has been well studied in predator-prey systems, but its functioning within a trophic level remains poorly understood. Eavesdropping, use of signals by unintended recipients, is of particular interest because eavesdroppers may exert selective pressure on signaling systems. We provide the most complete study to date of eavesdropping between two competing social insect species by determining the glandular source and composition of a recruitment pheromone, and by examining reciprocal heterospecific responses to this signal. We tested eavesdropping between Trigona hyalinata and Trigona spinipes, two stingless bee species that compete for floral resources, exhibit a clear dominance hierarchy and recruit nestmates to high-quality food sources via pheromone trails. Gas chromatography-mass spectrometry of T. hyalinata recruitment pheromone revealed six carboxylic esters, the most common of which is octyl octanoate, the major component of T. spinipes recruitment pheromone. We demonstrate heterospecific detection of recruitment pheromones, which can influence heterospecific and conspecific scout orientation. Unexpectedly, the dominant T. hyalinata avoided T. spinipes pheromone in preference tests, while the subordinate T. spinipes showed neither attraction to nor avoidance of T. hyalinata pheromone. We suggest that stingless bees may seek to avoid conflict through their eavesdropping behavior, incorporating expected costs associated with a choice into the decision-making process.