Indoor and outdoor winter activity of Culicoides biting midges, vectors of bluetongue virus, in Italy.

Indoor and outdoor winter activity of Culicoides spp. (Diptera: Ceratopogonidae) in central Italy was investigated in order to evaluate whether indoor activity might account for the overwintering of bluetongue virus, as has been hypothesized by some authors. Weekly Culicoides collections were performed at three farms over three consecutive winter seasons. At each farm, two black-light traps were operated simultaneously, indoors and outdoors. Culicoides were identified using both morphological and molecular means. The Culicoides obsoletus group accounted for 98.2% of sampled specimens. Within this group, C. obsoletus s.s. accounted for 56.8% and Culicoides scoticus for 43.2% of samples. Nulliparous, parous and engorged females were caught throughout the entire winter, both indoors and outdoors. At times, indoor catch sizes outnumbered outdoor collections. A significant inverse correlation was found between minimum temperature and the proportion of indoor Culicoides of the total midge catch, thus indicating that lower outdoor temperatures drive Culicoides midges indoors. High rates of engorged females were recorded indoors, possibly as the result of the propensity of C. obsoletus females to feed indoors. Higher proportions of parous females were found in indoor than in outdoor catches, indicating higher survival rates indoors and, consequently, higher vectorial capacities of midges sheltering indoors compared with those remaining outdoors.

A 2-yr Mosquito Survey Focusing on Aedes koreicus (Diptera: Culicidae) in Northern Italy and Implications for Adult Trapping.

Aedes koreicus (Edwards) is an invasive mosquito species, like Aedes albopictus (Skuse) and Aedes japonicus japonicus (Theobald), that has already colonized a large part of northeastern Italy and other European countries. Despite its rapid expansion, information about adult distribution and trapping is lacking. Here, we conducted a 2-yr longitudinal survey using adult traps to investigate the spatiotemporal distribution of Ae. koreicus and evaluated the effectiveness of three trapping devices in Latin square experiments conducted in an urban site and a forested site. The following three different traps were compared: a CO2-baited Biogents (BG) Sentinel trap, a CO2-baited Centers for Disease Control and Prevention light trap (CDC trap), and a grass infusion-baited gravid trap.In northern Italy, Ae. koreicus was collected from late April to early November, with peak of abundance observed in August. Aedes koreicus was more abundant in 2015 than in 2014 because of higher temperatures during summer. Unlike Ae. albopictus, the abundance of Ae. koreicus was not related to the altitude of the sampling locations in the range 241-660 m above sea level. The BG Sentinel and gravid traps collected significantly more Ae. koreicus than the CDC trap in the urban site, whereas there was no significant difference between the three traps in the forested site. In the urban site, the BG Sentinel trap and the gravid trap were the most effective for collecting Ae. albopictus and Culex pipiens L., respectively. In the forested site, Cx. pipiens was primarily collected by the CDC trap.