RESUMEN
Wolbachia pipientis (Hertig, 1936), also referred as Wolbachia, is a bacterium present across insect taxa, certain strains of which have been demonstrated to impact the fitness and capacity to transmit viruses in mosquitoes, particularly Aedes aegypti (Linnaeus, 1762). Most studies examine these impacts in limited sets of environmental regimes. Here we seek to understand the impacts of environmentally relevant conditions such as larval density, temperature, and their interaction on wAlbB-infected A. aegypti. Using a factorial design, we measured wAlbB stability (relative density, post-emergence in females, and in progeny), the ability for wAlbB to induce cytoplasmic incompatibility, and bacterial effects on mosquito fitness (fecundity, fertility, and body mass) and performance (adult survival and time to pupation) across 2 temperature regimes (fluctuating and constant) and 2 initial larval densities (low and high). Fluctuating daily regimes of temperature (27 to 40 °C) led to decreased post-emergence wAlbB density and increased wAlbB density in eggs compared to constant temperature (27 °C). An increased fecundity was found in wAlbB-carrying females reared at fluctuating temperatures compared to uninfected wild-type females. wAlbB-carrying adult females showed significantly increased survival than wild-type females. Contrarily, wAlbB-carrying adult males exhibited a significantly lower survival than wild-type males. We found differential effects of assessed treatments (Wolbachia infection status, temperature, and larval density) across mosquito sexes and life stages. Taken together, our results indicate that realistic conditions may not impact dramatically the stability of wAlbB infection in A. aegypti. Nonetheless, understanding the ecological consequence of A. aegypti-wAlbB interaction is complex due to life history tradeoffs under conditions faced by natural populations.
Asunto(s)
Aedes , Larva , Temperatura , Wolbachia , Animales , Aedes/microbiología , Aedes/crecimiento & desarrollo , Aedes/fisiología , Wolbachia/fisiología , Larva/crecimiento & desarrollo , Larva/microbiología , Femenino , Masculino , Densidad de Población , Fertilidad , Aptitud GenéticaRESUMEN
BACKGROUND: Amblyomma americanum, the lone star tick, is an aggressive questing species that harbors several pathogens dangerous to humans in the United States. The Southeast in particular has large numbers of this tick due to the combined suitable climate and habitats throughout the region. No studies have estimated the underlying distribution of the lone star tick across the state of Georgia, a state where it is the dominant species encountered. METHODS: Ticks were collected by flagging 198 transects of 750 m2 at 43 state parks and wildlife management areas across the state from March to July of 2022. A suite of climate, landscape, and wildlife variables were assembled, and a logistic regression model was used to assess the association between these environmental factors and the presence of lone star ticks and to predict the distribution of these ticks across the state. RESULTS: A total of 59/198 (30%) transects sampled contained adult or nymph A. americanum, with the majority of transects containing these ticks (54/59, 91.5%) in forested habitats. The presence of A. americanum was associated with elevation, normalized difference vegetation index (NDVI) on January 1, isothermality, temperature seasonality, and precipitation in the wettest quarter. Vast regions of central, eastern, and southern coastal Georgia (57% of the state) were categorized as suitable habitat for the lone star tick. CONCLUSIONS: This study describes the distribution of the lone star tick across the state of Georgia at a finer scale than the current county-level information available. It identifies specific variables associated with tick presence and provides a map that can be used to target areas for tick prevention messaging and awareness.