Impact on vector competency and future work
The C . variipennis complex is one of many vector groups in
which species delimitation can be challenging (Carlson, 1980; Nolan et
al., 2007; Palacios et al., 2014; Rivas, Souza, & Peixoto, 2008;
Sebastiani et al., 2001); however, species identification is an integral
part of vector surveillance. The species status of these group members
has implications for vector surveillance, as any ambiguity in
identification will lead to unreliable data. For example, while C.
albertensis and C. sonorensis occur in sympatry, only C.
sonorensis is a reported as a vector species (Wilson et al., 2009). The
addition of the non-competent vector species when conducting serological
surveys could lead to a severe underestimation of the infection rate
within the vector species. As BTV and EHDV are expanding northward into
eastern Canada (Allen et al., 2019), it has been suggested that the
dispersal of C. sonorensis to new areas could be to blame for
this incursion (Jewiss-Gaines et al., 2017). Specimens assigned toC. sonorensis by Jewiss-Gaines et al. (2017) were included in the
present study and cluster instead with C. albertensis (“ON”,
Fig. 1). Thus, there are likely alternative reasons for this expansion,
including an unidentified vector species outside of the C.
variipennis complex. Accurate species-level delimitation within this
complex is sorely needed for proper vector surveillance. Additionally,
elucidating the evolutionary history of these groups can lead to a
better understanding of how some species become highly competent vectors
while closely related taxa are not. The detection of hybridization
within a vector species may be evidence of recent speciation, but it
also highlights a potential path of introgression for genes controlling
vector competency (Ciota, Chin, & Kramer, 2013; Mallet, 2005).