Blood-sucking sand flies like to eat marijuana

When they are not sucking the blood of animals, sand flies tend to nibble the marijuana plant (Cannabis sativa), suggests a new search.

An international team of scientists discovered that, in proportion to its abundance, Cannabis sativa was consumed by sandflies much more often than expected, suggesting that it was very attractive to insects.

According to an article published in the newspaper Proceedings of the National Academy of Sciencesthe results may have implications for controlling the spread of sandfly-borne diseases – found around the world.

Sandflies suck the blood of vertebrates to provide the proteins necessary for the maturation of their eggs. During this process, flies can transmit pathogens to humans, causing diseases such as bartonellosis and leishmaniasis, which infect between 4 and 12 million people worldwide and cause between 20,000 and 50 000 deaths a year.

In addition to sucking blood, women and men consume energy from plant sugars. These meals may be in the form of sugary solutions such as nectar or plant sap – which flies can access by piercing the leaves and stems with their needle-shaped mouthparts.

As a result, the availability of their favorite plants can influence where and when sand flies are distributed. This helps researchers to identify the areas most at risk of infection by the diseases they transmit.

Wild cannabis plants, near Bura, Kazakhstan David Poché

For this study, led by Ibrahim Abbasia of the Israel-Canada Institute of Medical Research and the Hebrew University of Jerusalem, researchers used next-generation gene sequencing techniques to determine the types of plant meal that flies were eating.

The team trapped sandflies in five unique areas – in Brazil, Ethiopia, Kazakhstan and Israel / Palestine – and tested them, concluding that they had ingested a variety of plants. According to the analysis, the most consumed plant in four of the five sites was Cannabis sativa, despite its apparent lack of abundance in the areas studied.

While the authors could only speculate on why sandflies prefer to eat marijuana plants, the results could provide a potential new avenue for controlling sandfly populations and mitigating the spread of the disease.

"A new approach to fight against blood-sucking mosquitoes and sandflies exploits their diet using attractive toxic sugar baits [ATSBs] that emit olfactory signals to attract sand flies and mosquitoes, "wrote the authors. By adding cannabis extracts to these ATSBs, the authors could improve their effectiveness in controlling insect-spreading disease populations.