Sand Fly larvae are capable of positive chemotaxis: A proof of concept study using Phlebotomus papatasi as a model species

Authors: TSIKOLIA, MAIA - European Biological Control Laboratory (EBCL); TSAFRAKIDOU, PANAGIOTA - American Farm School; GKEKTSIAN, ARSEN - American Farm School; MIAOULIS, MICHAEL - European Biological Control Laboratory (EBCL); ROWLAND, TOBIN - Walter Reed Army Institute; CHASKOPOULOU, ALEXANDRA - European Biological Control Laboratory (EBCL)

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2024
Publication Date: 5/24/2024
Citation: Tsikolia, M., Tsafrakidou, P., Gkektsian, A., Miaoulis, M., Rowland, T., Chaskopoulou, A. 2024. Sand Fly larvae are capable of positive chemotaxis: A proof of concept study using Phlebotomus papatasi as a model species. Journal of Medical Entomology. 61(4)869-876. https://doi.org/10.1093/jme/tjae072.
DOI: https://doi.org/10.1093/jme/tjae072

Interpretive Summary: Sand flies are biting insects of major public health importance, capable of transmitting Leishmania - a disease endemic in up to 92 countries worldwide posing a risk to an estimated 3.5 billion people, with an annual death toll ranging between 25,000 and 65,000 globally. Sand fly control programs are being challenged world wide due to the absence of knowledge on the behavior of the sand fly immature life stages (larval stages). Through this study we designed and applied innovative experiments that have resulted in novel information on the chemical ecology of sand fly larvae. This knowledge shall enable a new path of research leading eventually to the development of novel tools for the control of sand flies in a holistic, integrated approach targeting both the adult and larval sand fly stages.

Technical Abstract: Phlebotomine sand flies are important vectors of pathogens of medical and veterinary importance, such as the Leishmania parasites responsible for 700,000 – 1 million new cases of leishmaniasis every year. The vast majority of the currently available sand fly surveillance and control tools are tailored against the adult stages, due to the limited knowledge on the ecology of the larval stages. Since vector control is primarily an ecological problem an in depth understanding of the behavior of the targeted insect pests across all the different stages of their development is required prior to the development of effective control strategies. It is well known that chemical cues play important role on insect behavior. While there are numerous studies investigating the behavior of adult sand flies in response to chemical sources, there is currently no information available on the response of their larval stages. In this study novel bioassays were constructed to investigate the effect of chemical cues (gustatory and olfactory) on the behavior of sand fly larvae of Phlebotomus papatasi sp. Sand fly larvae exhibited a clear food preference within a few hours of exposure in a two-choice assay context, while, also, demonstrated positive chemotaxis in response to volatile stimuli emitted from their preferred food source. Identification of the specific chemical compounds (or the combination thereof) eliciting attractance response to sand fly immature stages could lead to the development of innovative, and targeted (larval-specific) tools for the surveillance, and management of these important public health pests.