Roob la Dhac
From Halbeeg, the open encyclopedia · Af-Soomaali
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Roob la Dhac is a Somali term for small animals belonging to the family Trombidiidae. They are arachnids—part of the group that includes spiders and scorpions—and possess three pairs of legs when fully developed. Their bodies are covered with fine, hair-like structures resembling soft velvet, which explains their name in other languages: 'velvet mite'.
The Somali name derives from the creatures' characteristic behavior. During the rainy season, especially in the early days after rain falls on wet ground, they emerge from the soil and spread across the surface. Rural Somali communities regard their appearance as a sign of approaching rains.
Appearance
Most species are reddish-brown and shiny, sometimes orange. They typically measure several millimeters across and are larger than most other mites. The body is divided into two sections that are not sharply distinguished, and the eyes are small and positioned to the sides. The body hairs aid in sensing moisture and temperature, and also serve as a defense against certain predators.
Life cycle
The life cycle undergoes significant changes. Eggs are laid in the soil. The larval stage possesses only six legs and typically parasitizes other arthropods—such as insects, arachnids, or flying insects—by feeding on their fluids. The later stages (nymph and adult) are free-living predators that consume the eggs and other small soil-dwelling organisms.
Habitat and distribution
They inhabit soil, leaf litter, and soil crevices. For most of the year they remain in the soil unseen; when humidity rises they emerge to the surface to search for food and mates. Their appearance therefore correlates with the rainy seasons of areas in semi-arid and arid regions, including East Africa.
Relationship to humans
Species in this family are not known to bite humans or transmit disease. Because the larvae parasitize arthropods and the adults feed on arthropod eggs, they are considered part of the soil ecosystem's mechanism for regulating arthropod populations. Some traditional practices have used their reddish color for medicinal purposes, though such use lacks verified health evidence.