17 - Identifying and Monitoring Mosquito Predators through Fecal Sample Analysis

Abstract: Population reduction or elimination is a common goal in vector control. As technologies such as sterile insect technique and use of genetically engineered mosquitoes are applied in the field, it is important to consider the ecological role that mosquitoes play in the food web.

Predators are one group of non-target organisms that interacts closely with mosquitoes. Although it is difficult to directly observe predation of adult An. coluzzii, many generalist predator species are likely to consume An. coluzzii. The frequency of predation within these non-target species may also be seasonally or geographically variable.

We developed a qPCR method to identify predators of An. coluzzii by detecting Anopheles presence in feces from both bat and bird species. The method amplifies a section of ribosomal DNA from the 28S region unique to Anopheles. The technique is non-invasive and lends itself to adaptable field collection, with the ability to preserve samples in ethanol and extract samples using a straightforward method.

Currently, this assay is being applied to a field study that establishes three predators of adult Anopheles coluzzii in São Tomé and Príncipe, Africa. Three likely candidate predators were identified, including two Swift species (Cypsiurus parvus and Apus affinis) and one bat species (Hipposideros ruber). In initial assay results from a subset of samples, Anopheles DNA was detected in feces from all three predator species. When the entire dataset of 79 bird and 58 bat samples from across the two islands is assessed, the rate of An. coluzzii predation will be identified and compared for each predator species. This data will be used to explore seasonal or geographical differences in rates of predation. In the future, this method can be used to examine the impact of vector control on the food web or non-invasively monitor range expansion of Anopheles mosquitoes.