Why do the males of Eulaema nigrita (Hymenoptera: Euglossini) harvest the mesophyll from leaves of Guarea guidonia (Meliaceae)?

Abstract

Males of Euglossini bees harvest aromatic compounds to synthesize sexual pheromones. This work describes the euglossine Eulaema nigrita harvesting mesophyll from leaves of Guarea guidonia for the first time. Observations were made at the Northern Atlantic Coast of Brazil and the following questions were analyzed: 1) Are the males extracting aromatic compounds  from the leaves of G. guidonia? 2) If so, what are the aromatic compounds attracting the males? 3) Why do males harvest on the same plant specimens and ignore other in the surroundings? Published data confirm that the leaves of G. guidonia produce sesquiterpenes, which are the most exploited floral aromas by Eulgossine. During harvest, males scrape mesophyll with their mandibles leaving intact the leaves nervure. They often aggregate on the same plant showing antagonistic interactions. This foraging pattern suggests that males benefit from inducible plant defenses, that is, the positive feedback on the synthesis of sesquiterpene.