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Replication of arboviruses, including orbiviruses, within the vector has been shown to be temperature dependent. Cooler ambient temperatures slow virus replication in arthropod vectors, whereas viruses replicate faster and to higher titers at warmer ambient temperatures. Previous research with epizootic hemorrhagic disease virus (EHDV) serotype 1 demonstrated that higher temperatures were associated with shorter extrinsic incubation periods in Culicoides sonorensis Wirth & Jones, a confirmed vector of EHDV in North America. To further our understanding of the effect of temperature on replication of EHDV within the vector, C. sonorensis were experimentally infected with one of three EHDV strains representing three serotypes (1, 2, and 7). Midges were fed defibrinated white-tailed deer (Odocoileus virginianus) blood spiked with EHDV (≥106.5 TCID50/ml) through a parafilm membrane using an artificial feeding device and were then held at 20, 25, or 30°C. In addition to this in vitro method, a white-tailed deer experimentally infected with EHDV-7 was used to provide an infectious bloodmeal to determine if the results were comparable with those from the in vitro feeding method. Whole midges were processed for virus isolation and titration at regular intervals following feeding; midges with ≥102.7 TCID50 were considered potentially competent to transmit virus. The virus recovery rates were high throughout the study and all three viruses replicated within C. sonorensis to high titer (≥ 102.7 TCID50/midge). Across all virus strains, the time to detection of potentially competent midges decreased with increasing temperature: 12–16 d postfeeding (dpf) at 20°C, 4–6 dpf at 25°C, and 2–4 dpf at 30°C. Significant differences in replication of the three viruses in C. sonorensis were observed, with EHDV-2 replicating to a high titer in a smaller proportion of midges and with lower peak titers. The findings are consistent with previous studies of related orbiviruses, showing that increasing temperature can shorten the apparent extrinsic incubation period for multiple EHDV strains (endemic and exotic) in C. sonorensis.

Large numbers of a cockroach that resembled the German cockroach, Blattella germanica (L.), were observed during winter 2005-2006 in home turf settings in Weslaco, TX, 11 km from the U.S. border with northeastern Mexico. In June and July 2006, this cockroach was observed at night on the foliage of soybean, Glycine max (L.) Merr., in numbers often exceeding 50 per m row. Because of its similarity to B. germanica, but with the characteristic of flying frequently, we suspected that our observations might be of the Asian cockroach, Blattella asahinai Mizukubo. Using a combination of morphological characters, cuticular hydrocarbons, and sequences of the mitochondrial cytochrome oxidase II gene, we definitively identified this cockroach as B. asahinai. B. asahinai was frequently observed feeding on sentinel eggs of Helicoverpa zea (Boddie) and Spodoptera exigua (Hübner). This cockroach was the dominant egg predator in soybean during 2006, making up 36.4% of all predators observed feeding on eggs. B. asahinai was only observed occupying the soybean canopy nocturnally, and it made up 53.7% of predators observed feeding at night. We speculate that B. asahinai may serve as an important beneficial insect in soybean and other crops.