J. Swanson et al., Overwintering and establishment of Aedes albopictus (Diptera : Culicidae) in an urban La Crosse virus enzootic site in Illinois, J MED ENT, 37(3), 2000, pp. 454-460
In 1997, Aedes albopictus (Skuse) was discovered in Peoria, IL, a known foc
us of La Crosse (LAC) virus transmission. This accidental introduction prov
ided an opportunity to determine whether Ae, albupictus would reemerge in t
he spring or summer and, if successful overwintering occurred. to follow ch
anges in the geographic range of Ae, albopictus, and to compare its distrib
ution to that of the local treehole mosquito and LAC vector Aedes triseriat
us (Say). In 1998 25 oviposition traps were placed in and around the area o
f the initial Ending of lie. albopictus, with adult collections by aspirato
rs and larval collections from water-holding containers used to identify ar
eas of additional activity. Ae. albopictus successfully survived the mild 1
997-1998 El Nino winter, and expanded its range during 1998 By September 19
98, Ae, albopictus oviposited in all 25 traps, including traps near and in
wooded sites. Intensity of oviposition activity (number of eggs pet. positi
ve trap) ranged from 20-40, lower than the range for Ae. triseriatus, which
was us high as 175 eggs per infested trap in mid-August. Prevalence of Ae,
albopictus increased through September. where as the prevalence of Ae tris
eriatus declined starting in mid-July. Although direct competition between
the two mosquito species cannot be inferred based on this surveillance effo
rt, a gradual range expansion was observed, and Ae. albopictus eggs were co
llected in traps where initially only Ae. triseriatus oviposition activity
was detected.