ARTHROPOD MUSEUM NOTES
Number 111 • April 24, 2014 • Jeffrey K. Barnes
Genus and species: Dermanyssus gallinae (De Geer)
Chicken mites are ectoparasites of poultry and other birds. They will also bite humans, and they sometimes enter homes and other buildings where there are roosting birds. However, they cannot live and reproduce on human hosts. People that are bitten often complain of severe itching, and the mites can cause papular dermatitis, vesicles, and even urticarial plaques. The usual source of chicken mite dermatitis in humans is birds and bird nests, including pigeons, finches, chickens, parakeets, canaries, and starlings. Normally, the mites take blood from resting birds at night, usually feeding around the breast and legs of hens, causing irritation and reduced egg production. During daylight, the mites can be found in nest or in crevices in poultry houses. When conditions are right, the life cycle can be completed within seven days, leading to rapid population growth. Under natural conditions, populations peak in summer, and the mites become inactive in winter. Flocks can become anemic under pressure from large populations of chicken mites. The mites also vector some bird diseases. Unfed mites are yellow or brown. Those engorged with a blood meal are dark brown or black. Eggs are deposited in crevices or under debris in poultry houses, or in the nests of chickens and other birds. Oviposition starts withing 24 hours after a blood meal. Six-legged larvae hatch in two to three days. They do not feed, and they molt to become eight-legged protonymphs in one to two days. Protonymphs take a blood meal and molt to deutonymphs one to two days later. Deutonymphs also take a blood meal and molt to the adult stage in one to two days. Adults can survive without a blood meal for four to five months.