A group of researchers from Research Support Foundation of the State of São Paulo (FAPESP) identified a new beetle that causes the production of red propolis. The findings are reported in an article published in the journal The Science of Nature.
Jairo Kenupp Bastos first heard about the insect while visiting Canavieiras, on the southern coast of Bahia. “Local beekeepers told me about a small beetle that makes holes in a plant called Dalbergia ecastaphyllum [Coinvine]a member of the pea family, and that the holes leaked a resin used by bees to make red propolis,” said Bastos, professor of pharmacognosy (the study of medicines isolated from natural sources such as plants, animals and minerals) at Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (FCFRP-USP).
honey bees (Apis mellifera) harvest the resin and mix it with wax, pollen and enzymes to make red propolis, the second most produced and commercialized propolis in Brazil. The red color derives from the resin and has antioxidant, anti-inflammatory and antitumor properties.
To understand more about the process, Bastos took several beetle larvae to the Museum of Zoology of the City of São Paulo, where he was told that adult specimens were needed to correctly identify the insect. He invited the doctoral student Letizia Migliore to help with the mission, going to the countryside of Canavieiras in search of the plant with its beetles. She was accompanied by Gianfranco Curletti, an entomologist affiliated with the Carmagnola Civic Museum of Natural History, Italy; Gari Ccana-Ccapatinta, postdoctoral fellow at the FCFRP-USP; and Jean Carvalho, a biologist and beekeeper from Canavieiras.
“The beetle is very small, so it was not an easy task, but we managed to collect some males and females, which were fixed in 70% ethanol and taken to the museum, where they were analyzed under a microscope. That’s how we discovered this new species of the family buprestidaewhich was named after Agrilus propolis,” recalled Migliore.
In addition to Curletti, Gabriel Biffi (head of the Coleoptera Lab) and Sônia Casari, Migliore’s supervisor, also participated.
“At the same time, phytochemical analyzes were carried out in the Pharmacognosy Laboratory [da FCFRP-USP] to confirm that the resin and propolis had the same chemical composition, proving their botanical origin and showing that this new species of beetle contributes to the production of the medicinal substance”, commented Ccana-Ccapatinta.
Transformation
The combined research of the two groups provides an overview of the process. Beetle larvae develop inside the stems of D. ecastaphyllum and, when they reach adulthood, they emerge through holes, together with the resinous exudate (a kind of perspiration).
They were funded by FAPESP through a Thematic Project led by Bastos and a doctoral scholarship granted to Jennyfer Mejía, co-author of the article.
“The paper is extremely important because it shows that the agent that induces the host plant to produce the key ingredient in red propolis has finally been identified. Until now, we had no information about the species of insect that could be behind this phenomenon,” said Casari, adding that the data serve as a basis for further research on the production of red propolis, which is sold at a high price and, therefore, it has meaning. A kilo was worth $150 on the market in 2019, when the research was done.