A wide variety of plant and animal pathogens have evolved transmission cycles that require arthropod vectors. This strategy for transmission has evolved independently several times, and many of the world’s most medically and economically important pathogens are spread by insect vectors. Vector-borne disease (VBD) transmission is remarkably complex because interactions between pathogens, vectors, hosts, and their physical environment dictate dynamics.
The biology of disease vectors has historically been studied in the context of control, leaving many aspects of the basic biology, especially behavior and life history, of these animals relatively ignored. Over the last several decades there has been a resurgence of interest in the biology of vectors, including how their behavior influences disease transmission dynamics. The emerging data have begun to provide new insights and have highlighted the potential importance of variation of vector behaviors and life history traits (1) across individual lifespan, (2) among individuals within populations, and (3) in response to environmental variation (e.g., temperature change) (Fig. 1) to transmission dynamics.
Figure 1: Vector behaviors, such as biting rate and host preference, and life history traits such as survivorship, are important determinants of transmission dynamics. Currently most representations of vector behavior and life history are integrated into models as constants (A). However, variation across vector lifespan (B), within populations (C), or in response to environmental drivers (D) are all likely to be important for transmission dynamics.
Vector behaviors such as biting rate, host preference, dispersal, and the effects of these behaviors on vector mortality and population growth have long been considered important drivers of VBD dynamics. Understanding variation in these traits and how environment drives them is necessary for truly understanding VBD dynamics. This viewpoint is particularly important if we are to develop a general framework that can predict transmission across a diversity of hosts, pathogens, and vectors. Yet the role of vectors in models of disease dynamics is often distilled to simple measures of vector traits that ignore this variation (Fig. 1). Better empirical characterization of behavior and incorporation of behavioral variation through time and space into theoretical models will improve our general understanding of VBDs. Fully integrating vector behavior into our understanding of disease transmission will require theoretical and empirical biologists working side-by-side. Cooperation between modeling and data collection parties will lead to more detailed and targeted models which can better inform control strategies and policies, while also highlighting key experiments to fill critical gaps in our understanding.
The VectorBehavior in Transmission Ecology Research Coordination Network (VectorBiTE RCN) seeks to build a collaborative network of researchers working on VBDs and to provide them with tools to better understand and explore how variation in vector behavior and life history drive transmission dynamics.