Arboviruses, such as dengue virus and West Nile virus, represent a serious threat to more than half of the world’s population. Their transmission is facilitated by a complex series of molecular interactions with their mosquito host. Characterizing these interactions is a major research priority that will facilitate the development of new tools and techniques to control mosquito-transmitted disease.
However, there is a third player in this story: the mosquito microbiome. There is a diverse array of microorganisms including, bacteria, fungi, algae and insect-specific viruses that can associate with mosquitoes. They primarily reside in the mosquito gut, and form a complex and variable microbial community referred to as the ‘microbiota’, which can influence many aspects of mosquito biology from larval development to egg production.
It has also been well established that the microbiota interacts with the mosquito immune system. And, there is a growing body of evidence demonstrating that the presence of certain microorganisms can actually enhance or limit a mosquito’s potential to harbor and transmit certain medically-important pathogens.
Notable amongst these is Wolbachia pipientis, a bacterial endosymbiont that forms intricate relationships with its hosts, modifying many aspects of their biology, and inhibiting infection with many important arboviruses. Consequently, Wolbachia-infected mosquitoes are currently being used in disease control programs around the world.
Wolbachia and other mosquito-associated microorganisms rely on their host to obtain the nutritional resources they need to survive, and this can greatly perturb host metabolism. Arbovirus infection is also heavily dependent on mosquito nutritional resources, and has been linked to mosquito lipids, insulin signaling, and essential micronutrients, amongst others. These host-microbe metabolic interactions can directly or indirectly influence mosquito immunity and pathogen transmission, but crucially, they remain poorly understood.
My laboratory’s primary research aim is to improve understanding of the relationships between mosquitoes, microorganisms and arboviruses, particularly as they relate to host metabolism and immunity. We will use this information as the basis for developing new mosquito control tools, and optimizing current control approaches
Specific research aims
Characterize the microbiota of mosquitoes in Florida
Florida is a hotspot for mosquito biodiversity in the United States, with 80 species present across the state. This includes major vectors of arboviral disease, both native and invasive, and numerous exotic and understudied mosquito species. In our location at the Florida Medical Entomology Laboratory, we are well situated to study wild populations of these species, and to build an understanding of the microorganisms that associate with them in nature.
My aim is to understand why certain microorganisms associate with certain Floridian mosquito species under different conditions. I am particularly interested in variation in mosquito microbial communities between species, between populations of the same species, and due to environmental factors, including human-driven environmental factors. This research aim will serve as the basis for future projects in the lab, as identifying which microorganisms are associated with different mosquito populations under different conditions is the first step towards a broader goal of elucidating the roles of specific microorganisms in mosquito biology.
Determine how the composition of a mosquito’s diet impacts its microbiome
Mosquito diets in nature can be complex and can vary greatly across different habitats. Mosquito larvae feed on the biological material found in their aquatic habitat, which can include decaying plant and animal matter, and microorganisms. Adult females feed on blood for egg production, and also use nectar as a carbohydrate source, while adult males are restricted to feeding on nectar.
These nutritional sources will each favor the growth of different environmental microorganisms that could be ingested by a mosquito, but will also shape the metabolic environment of mosquito tissues, particularly the gut, where the majority of the microbiota dwell. As different microorganisms have distinct metabolic needs, the bioavailability of key nutritional resources will influence community composition, and potentially moderate the host immune response.
I am interested in identifying key metabolites in the diet of larval and adult mosquitoes that cause certain mosquito-associated bacteria to prosper or struggle. These data will then be used to identify patterns underlying mosquito-microbe and microbe-microbe interactions to elucidate microbial niches in the context of mosquito biology.
Elucidate the role of mosquito metabolism in mosquito-microbe-arbovirus interactions
Mosquitoes possess vast networks of metabolic pathways that help to drive their physiological processes, from blood digestion to egg development. Many of these are also intrinsically linked to their immune system, and therefore play an important role in their response to arboviral infection. Critically, these interactions can be moderated by the presence of microorganisms, including bacteria and fungi.
Recent evidence has highlighted the importance of certain host lipids and micronutrients, like iron, to arboviral infection in mosquitoes. I am interested in building on these data and improving our understanding of metabolic-immune networks that underlie mosquito-microbe-arbovirus interactions. To do so, I plan to activate or suppress key mosquito metabolic pathways, and then gauge the impact on the host, its microbiota and infection with medically-important arboviruses.
Examine plasticity in Wolbachia-host immune interactions under different host metabolic states
Infection with the bacterial endosymbiont Wolbachia occurs naturally in many important mosquito vectors, including the dengue and chikungunya vector, Aedes albopictus, and the West Nile vector, Culex quinquefasciatus. These Wolbachia strains have long-established associations with their hosts, but the relationships are not completely mutualistic. They can have a broad impact on host physiology, and alter host reproductive biology to promote their own propagation. Critically, these native Wolbachia infections can still induce an immune response and parasitize host metabolic resources.
I am interested in understanding more about the role of metabolism in the relationship between native Wolbachia infections and their mosquito hosts. Specifically, how Wolbachia x mosquito immune interactions vary in response to changes to host metabolism, and how this affects host biology and response to arboviral infection.
Data from these experiments will help us to understand plasticity in Wolbachia-host relationships; the extent to which they are capable of mounting a stronger or weaker immune response after a metabolic stimulus. This is directly relevant to the ongoing use of Wolbachia as a mosquito control tool, as Wolbachia-host relationships are hypothesized to become more benign, and more similar to a native Wolbachia infection over time, which may eventually weaken their ability to block arboviral infection.
UF/IFAS - Understanding GMO Mosquitoes