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Social insects are frequently observed in symbiotic association with bacteria that produce antimicrobial natural products as a defense mechanism. There is a lack of studies on the microbiota associated with stingless bees and their antimicrobial compounds. To the best of our knowledge, this study is the first to report the isolation of Paenibacillus polymyxa ALLI-03-01 from the larval food of the stingless bee Melipona scutellaris. The bacterial strain was cultured under different conditions and produced (L)-(-)-3-phenyllactic acid and fusaricidins, which were active against entomopathogenic fungi and Paenibacillus larvae. Our results indicate that such natural products could be related to colony protection, suggesting a defense symbiosis between P. polymyxa ALLI-03-01 and Melipona scutellaris.

Wax constituents produced by worker bees and the chemistry of the nest batumen (mixture of wax, mud, and floral materials) in a Melipona scutellaris colony changed when it was invaded by Melipona rufiventris workers. Gas chromatography/mass spectrometry analyses showed that after invasion, the M. scutellaris workers of the invaded colony produced waxes with higher relative abundance of triacontanyl acetate and decreased the amounts of n-alkanes and n-9-alkenes. On the other hand, waxes from M. rufiventris workers displayed few changes. The change in the composition of the M. scutellaris waxes chemically differentiates that species from the M. rufiventris invader workers. Comparative analyses of batumens samples from pure and invaded colonies revealed greater amounts of terpenes and phenolic derivatives in the batumen from the invaded colony. This is the first report on the chemical characterization of batumens from stingless bees.