Do tigers hunt during the day? Diel activity of the Asian tiger mosquito, Aedes albopictus (Diptera: Culicidae), in urban and suburban habitats of North America

Abstract

Background Aedes (Stegomyia) albopictus (Skuse) impacts human outdoor activity because of its aggressive biting behavior, and as a major vector of mosquito-borne diseases, it is also of public health importance. Although most mosquito species exhibit crepuscular activity by primarily host seeking at dawn and dusk, Ae. albopictus has been traditionally characterized as a diurnal or day-biting mosquito. With the global expansion and increased involvement of Ae. albopictus in mosquito-borne diseases, it is imperative to elucidate the diel activity of this species, particularly in newly invaded areas. Methodology and principal findings Human sweep netting and carbon dioxide-baited rotator traps were used to evaluate the diel activity of Ae. albopictus in two study sites. Both trapping methods were used in New Jersey’s Mercer County, USA (temperate/urban), while only human sweep netting was used in Florida’s Volusia County, USA (subtropical/suburban). Human sweep netting was performed to determine adult mosquito activity at Sunrise, Solar Noon, Sunset, and Lunar Midnight. Because New Jersey is in a temperate area, diel activity was investigated during the early season (3–19 July), peak season (25 July-19 September), and late season (22 September- 22 October). Aedes albopictus showed the highest activity during peak and late seasons at Solar Noon (P < 0.05). At Sunrise and Sunset during the peak season, Ae. albopictus activity was similar. Lunar Midnight activity was significantly lower than Sunrise and Solar Noon (P < 0.05) but was similar to that of Sunset. In the late season, the highest activity was observed during Solar Noon while the least activity was observed during Sunrise and Lunar Midnight (P<0.05). Bottle rotator traps used in conjunction with the human sweep net technique exhibited similar results. Seasonal activity was not differentiated in Florida due to the consistent subtropical climate. The highest adult activity was observed at Sunrise using human sweep netting, but it was not significantly different from Solar Noon and Sunset. The lowest adult activity was observed at Lunar Midnight; however, it was not significantly different from Solar Noon and Sunset. These results provide evidence that the diel activity of Ae. albopictus, contrary to the common perception of its diurnal activity, is much more varied. Conclusion/Significance Involvement of Ae. albopictus in the transmission of debilitating mosquito-borne pathogens such as chikungunya, dengue, and Zika virus, coupled with its affinity to thrive in human peridomestic environments, substantiates that our findings have global implications in areas where Ae. albopictus populations established. It also highlights the importance of behavioral studies of vector species which will not only help mosquito control professionals plan the timing of their control efforts but also provides empirical evidence against conventional wisdoms that may unjustly persist within public health stewards.

Aedes albopictuscolonies from different geographic origins differ in their sleep and activity levels but not in the time of peak activity

“…albopictus. Many of these studies have used a variety of methods to measure their activity, in particular field-based captures (Delatte et al 2010, de Lima-Camara 2010, Casas Martínez et al 2013, Unlu et al 2021, Wilke et al 2023). Here, we used activity monitors to record mosquitoes’ activity patterns over a five-day period under constant temperature and humidity conditions, regular light/dark cycles, and in the absence of host cues.…”

“…This confirmed observations made in previous studies where populations from Gainesville, Brunswick, Jacksonville, and Kyushu displayed an unimodal pattern peaking at sunset, similar to the Florida and New Jersey Ae. albopictus populations examined in the field, except that these populations displayed a single peak in activity centered around solar noon (Unlu et al 2021). While significant differences in activity levels were observed throughout the day, most variations were observed during the sunset phase ( i.e.…”

“…For instance, Ae. albopictus from Mercer County in New Jersey (USA) and Volusia County in Florida, (USA) were shown by collection through human sweep netting and/or carbon dioxide-baited rotator traps to display unimodal activity patterns peaking during solar noon (Unlu et al 2021). Overall, the suburban population from Florida exhibited lower activity levels than the urban population from New Jersey.…”

Spatial and Temporal Distribution of Aedes aegypti and Aedes albopictus Oviposition on the Coast of Paraná, Brazil, a Recent Area of Dengue Virus Transmission

“…It is noteworthy that Ae. albopictus is a DENV vector in several Asian [68][69][70] Africans countries [45,46], as well as in some temperate countries such as Spain [71,72], France and Italy [73][74][75][76].…”

A comparative study of dengue virus vectors in major parks and adjacent residential areas in Ho Chi Minh City, Vietnam

“…Feeding activities of both vector species are primarily diurnal [12,13]. Although they often display a bimodal peak activity during the morning and late afternoon [14][15][16], the peak hours may vary depending on environmental conditions [17]. Because people may spend much of the day away from home, the risk of infection is not limited to residential areas.…”