Dark Banquet - Bill Schutt [81]
Commensalism (another type of mite/animal association) is a relationship between two organisms in which one benefits and the other neither benefits from the relationship nor is harmed. One example, in the case of mites, is a form of commensalism known as phoresy, in which a smaller organism (in this case, the mite) attaches itself to other organisms (like an insect) for the purpose of transportation. Since the carrier isn’t harmed, you can think of phoresy as a milder version of the passive transport we saw in bed bugs. In perhaps the strangest case of phoresy, hummingbird-flower mites (Proctolaelaps kirmsei) are chauffeured from flower to flower within the nasal cavities of the hummingbirds. Although the hummingbirds aren’t physically harmed by the mites, they both wind up competing for the same pollen and nectar—and so this isn’t really a textbook example of commensalism.
Acarologist Tyler Woolley lists five significant ways that mites affect humans: health (through transmission of diseases as well as our bodies’ allergic and inflammatory reactions to them), agriculture (they infest crops, household and garden plants, and farm animals), stored agricultural products (they cause tremendous damage to grains, cereals, and veggies in which they live and multiply), *126 biological control (in which predatory mites are involved in controlling pests like fire ants or even other mites), and aesthetics (nobody likes a mangy mutt or mite-damaged houseplants).
As a group, mites exhibit a bewildering variety of ways to make a living. For example, approximately 140 species of them have been identified as living in house dust. Additionally, if you look closely enough you’ll find mites infesting algae, books, cheese, dried fruits, dried meats, drugs, flour, fungi, furniture, grains (like corn, wheat, oats, barley, rye, buckwheat, and millet), jams, jellies, mattresses, mildew, mushrooms, nectar, nuts, paper, plant bulbs, pollen, seaweed, seeds, spores, straw, sugar, vanilla pods, and wallpaper. Mites affect hundreds of plant species, and pretty much every type of wild animal, farm animal, and pet you can name. For creatures troubled by mites, infestation sites range from ears to anuses and all stops in between.
Besides an allergic reaction to dust mites and their droppings, perhaps the most commonly encountered mite-related health problem is scabies. Caused by Sarcoptes scabiei. Scabies is a condition that produces a rash and intense itching.*127 The symptoms result from the host body’s reaction to mite-secreted and-excreted substances released as the mites go about their parasitic business. Young female scabies mites, which are about one-fiftieth of an inch long (a half millimeter), excavate a burrow in the host’s skin where a male soon joins them. Copulation occurs only once and renders the female fertile for life. Soon after, she emerges from the honeymoon suite (leaving the male behind to die). The pregnant female motors around the surface of the host (reaching speeds of up to 60 inches per hour) until she locates a site for a permanent burrow (hands and wrists are popular). Burrowing at a rate of about one-fifth of an inch per day (five