Review of the tribe Mutillini (Hymenoptera: Mutillidae) from the Oriental Region.

The species in the tribe Mutillini (Mutillidae: Mutillinae) sensu Waldren et al. (2022, in press) of the Oriental region are reviewed. Fourteen species in the genera Kurzenkotilla Lelej, 2005, Mutilla Linnaeus, 1758, Standfussidia Lelej, 2005, and Storozhenkotilla Lelej, 2005 are keyed, reviewed, and illustrated. The males of the genus Kurzenkotilla are described and associated with the females. One new species: Storozhenkotilla nathani Lelej, sp. nov., male is described from India (Karnataka and Kerala). New combinations are proposed for Kurzenkotilla harmandi (André, 1898), comb. nov., K. rufodorsata (Cameron, 1897), comb. nov., K. semiviolacea (André, 1896), comb. nov., K. cicatricifera (André, 1894), comb. nov., and Storozhenkotilla binghami (Lelej, 2005), comb. nov. Six new country records are presented: Kurzenkotilla niveosignata (André, 1894) from Pakistan, K. annamensis Lelej, 2005 from Thailand, K. visrara (Cameron, 1898) from India, K. scrobiculata (Hammer, 1962) from Nepal, K. rufodorsata (Cameron, 1897) from Nepal, and Storozhenkotilla binghami Lelej, 2005 from Sri Lanka. Specimens of Mutilla mikado Cameron, 1900 from China were misidentified as Mutilla europaea by Su et al. (2019), and we recognize M. mikado as the sole member of the genus Mutilla to occur in the Oriental region. A key to the species of Oriental Mutillini is provided.

A haemocyte tropism for an arbovirus.

Horizontally transmitted mosquito-borne viruses enter the midgut with a blood meal then disseminate to infect the salivary glands. En route to the salivary glands, these viruses encounter the plasma (haemolymph) and blood cells (haemocytes). Haemocytes respond to a variety of micro-organisms, but their role in virus replication and dissemination has not been described. To look for a potential haemocyte tropism for an arbovirus, a Sindbis virus was injected intrathoracically into four species of mosquito. Virus infects haemocytes as early as 6 h post injection (p.i.) and infection was evident in these cells for as long as 4 days p.i. More than 90 % of haemocytes were infected, most often the phagocytic granulocytes. Virus titres in the haemolymph increased from 24 h p.i. through 60 h p.i. Similar results were found when Aedes aegypti mosquitoes were injected with orally infectious Sindbis. These data prove that an arbovirus infects, and replicates in, haemocytes.

Fox squirrels (Sciurus niger) develop West Nile virus viremias sufficient for infecting select mosquito species.

The West Nile virus (WNV) viremia and shedding profiles of 11 adult fox squirrels (Sciurus niger) infected by needle inoculation or mosquito bite were characterized. Daily mean titers (95% confidence intervals) for all squirrels on days 1 through 6 postexposure (p.e.) were: 10(1.7 (1.32.1)), 10(4.4 (4.04.8)), 10(5.3 (5.05.6)), 10(4.4 (3.94.9)), 10(2.7 (2.03.4)), and 10(1.1 (0.52.1)) plaque-forming units (PFU)/mL. The highest WNV serum titers of individual squirrels infected by needle inoculation or mosquito bite ranged from 10(4.5) to 10(6.1) and from 10(5.1) to 10(5.3) PFU/mL, respectively. Nine (82%) squirrels, including all 4 squirrels infected by mosquito bite, had WNV serum titers > or =10(5.1) PFU/mL that persisted on average for 1.6 +/- 0.3 days. Infection and dissemination rates of Culex pipiens (L.) that fed on squirrels with serum titers of 10(4.4 +/- 0.1) PFU/mL were 56% and 13%, respectively. Both of these rates increased to over 80% when fed on squirrels with a mean WNV titer of 10(5.5 +/- 0.1) PFU/mL. Infection and dissemination also occurred in Aedes triseriatus (Say) but at a much lower rate. WNV was isolated from the oral and rectal cavities of all squirrels and from urine that was opportunistically collected from 5 squirrels. The largest quantity of WNV recovered from swabs of the oral cavity and urine was 10(3.1) PFU. The longest periods after exposure that WNV was isolated from the oral cavity and urine from a squirrel were 22 and 17 days p.e., respectively. WNV RNA was also detected in kidney tissue in 1 squirrel 29 days p.e., suggesting that fox squirrels can be persistently infected. Collectively these observations provide further evidence that squirrels can contribute to the natural history and epidemiology of WNV, especially in peridomestic environments.