Diel activity patterns of two distinct populations of Aedes aegypti in Miami, FL and Brownsville, TX

Abstract

The diel biting activity of Aedes (Stegomyia) aegypti (L) populations was extensively investigated in the early 1900s to gain more information on the biology of Ae. aegypti, and this information was used to devise effective approaches to controlling populations of this species and protect the human population from widespread arbovirus outbreaks. However, few contemporary studies are available regarding the diel activity patterns of Ae. aegypti. To assess the diel activity patterns of Ae. aegypti in southern Florida and Texas, we conducted 96-h uninterrupted mosquito collections once each month from May through November 2019 in Miami, Florida, and Brownsville, Texas, using BG-Sentinel 2 Traps. The overall diel activity pattern in both cities was bimodal with morning and evening peak activity between 7:00 and 8:00 and between 19:00 and 20:00. There were significant daily, monthly, seasonal, and site-specific differences in activity patterns, but these differences did not affect the overall peak activity times. These differences suggest daily, monthly, seasonal, and site-specific variations in human exposure to Ae. aegypti. Our observations can be used in planning and executing Ae. aegypti vector control activities in southern Florida and southern Texas, specifically those targeting the adult mosquito populations.

Figure 1

Diel activity patterns for Ae. aegypti populations at each of the 4 sampling sites in Miami, Florida. “Mean” on the graphs represent the mean number of female Ae. aegypti mosquitoes captured per trap/hour. The thick black line is the mean number of Ae. aegypti female mosquitoes captured per trap/hour throughout the study period from May to November 2019.

Figure 2

Diel activity patterns for Ae. aegypti populations at each of the 4 sampling sites in Brownsville, Texas. “Mean” on the graphs represent the mean number of female Ae. aegypti mosquitoes captured per trap/hour. The thick black line is the mean number of Ae. aegypti female mosquitoes captured per trap/hour throughout the study period from May to November 2019.

Figure 3

Diel activity patterns of Ae. aegypti in different seasons (Spring March–June, Summer June – September, Fall September–December). The y axis is the relative abundance of female Ae. aegypti; the number of female Ae. aegypti captured per trap/hour at all sites in each city.

Figure 4

Diel activity patterns of female Ae. aegypti mosquitoes in Miami, Florida and Brownsville, Texas. Relative abundance on the y axis represents the relative abundance of female Ae. aegypti mosquitoes captured per trap per hour throughout the sampling period, May through November 2019.

Figure 5

Maps of sampling sites in Brownsville, Texas (A) and Miami Dade County, Florida, (B). In Brownsville, the traps were moved from 2A to 2B and from 3A to 3B because mosquito caught dipped markedly at sites 2A and 3A. The traps were moved to the more productive sites 2B and 3B. In Miami, the trap was moved from site 2A to site 2B for the same reason as in Brownsville. The figure was produced using ArcGIS 10.2 (Esri, Redlands, CA), using freely available layers from the Miami-Dade County’s Open Data Hub—https://gis-mdc.opendata.arcgis.com/.