Trombidiidae, also known as red velvet mites, true velvet mites, or rain bugs, are small arachnids (eight-legged arthropods) found in plant litter and are known for their bright red color.
While adults are typically no more than in length, some species can grow larger and the largest, including the African Dinothrombium tinctorum and Indian Trombidium grandissimum, may exceed . This also makes them the largest mites, if disregarding ticks engorged after feeding; unlike those, D. tinctorum and T. grandissimum are harmless to humans.
Their life pattern is in stages similar to other members of the Prostigmata: egg, pre-larva, larva, protonymph, deutonymph, tritonymph and adult (male or female). They usually have only one breeding cycle per year.Zhang, Zhi-Qiang (1998) Biology and ecology of trombidiid mites (Acari: Trombidioidea) Experimental & Applied Acarology 22:139–155 PDF
They are active predators as grown adults. As larvae they are often parasites of insects and other arachnids. This lifestyle is typical of the Parasitengona.
One well-known species from Europe, Asia, and North Africa is Trombidium holosericeum. The systematics of this group has been in flux and many former subfamilies of this are now raised to families within the Trombidioidea.Makol, Joanna (2007) Generic level review and phylogeny of Trombidiidae and Podothrombiidae (Acari: Actinotrichida: Trombidioidea) of the world. Annales Zoologici 57(1): 1–194
List of genera
According to Joanna Makol Trombidiinae Leach, 1815 Allothrombium Berlese, 1903 synonyme Corethrothrombium Oudemans, 1928 & Mongolothrombium Feider, 1973 Andinothrombium Makol, 2007 Andrethrombium Makol, 2007 Arknotrombium Haitlinger, 2007 Azaritrombium Saboori, Bagheri & Haddad, 2005 Caenothrombium Oudemans, 1927 Calctrombidium Haitlinger, 2003 Clinotrombium Southcott, 1986 Darjeelingia Makol, 2007 Dinothrombium Oudemans, 1910 Dolichothrombidium Feider, 1945 Iranitrombium Saboori & Hajiqanbar in Saboori, Hajiqanbar & Irani-nejad 2003 Mesothrobium Hirst, 1926 synonyme Austrothrombium Womersley, 1934 Monotrombium Zhang in Zhang & Norbakhsh 1995 Oskootrombium Saboori, Bagheri & Haddad 2006 Paratrombium Bruyant, 1910 Pollicotrombium Southcott, 1986 Robauxthrombium Makol, 2007 Ronaldothrombium Makol, 2007 Trombidium Fabricius, 1775 synonyme Kaszabothrombium Fieder, 1973 Variathrombium Robaux, 1969 Wohltmannella Makol, 2007 Xenothrombium Oudemans, 1927
Human use
An oil made from Trombidium grandissimum is used in traditional Indian medicine.Oudhia, P. 1999b. Traditional medicinal knowledge about red velvet mite Trombidium sp. (Acari: Trombidiidae) in Chhattisgarh. Insect Environment 5(3):113.
References