Mosquito Bite Update

After posting this blog with photographs of a mosquito biting my arm in the middle of the afternoon, I had it identified on Bugguide as the eastern tree hole mosquito (ETM), Ochlerotatus triseriatus.  This turns out to be an unusual insect.

Although it does breed in moist holes in trees, it really specializes in tires, tires stored or trashed on the ground.  If you have ever tried to get all the water out of a tire on a creek cleanup, you know that it is a definition of forever.  This has become an important urban mosquito because of tire dumps and scrap yards around cities where there can be 60,000 mosquitoes per acre in the summer.

Eastern tree hole mosquito - Ilona

Asian tiger mosquito

At first glance to my untrained eye ETM looks a lot like the Asian tiger mosquito.  The differences are more obvious to an entomologist but include the abdomen which is mainly dark scaled with only the margins of the last four segments with pale patches, and legs that lack the white spots of the Asian tiger mosquito.

"Few mosquito species feed rodents. These mammals are just too jittery and quick to sit still for that. But Ochlerotatus triseriatus, even though it bites a wide variety of mammals, including humans and sometimes birds, particularly likes chipmunks and squirrels. These woodland rodents are active during the day when Ochlerotatus triseriatus is seeking hosts in the woods."  Bugguide

We are unlikely to see these during the evening when mosquitoes are abundant.  They tend to occur during the day, as mine was, when their mammal hosts are active.  The ETM transmits La Crosse encephalitis virus, an uncommon but significant disease.  While 70% of females hatching from infected eggs inherit the virus, the good news is that it isn't that common in most of its range.  There are around 72 cases per year in the US and it usually affects children.  If it only would transmit the disease to the wood rats in our house!