A velvet spider is poisonous

Red velvet mite

The Red velvet mite (Trombidium holosericeum), also Velvet mite or Mite called, belongs to the family of running mites (Trombidiidae) to the genusTrombidium. In general, the velvet mites are also known as red spiders because of their bright red color. The English name of the red velvet mite is Red Velvet Mite.

description

Most adult mites, like spiders, have four jointed pairs of legs and thus also belong to the group of arachnids. The running mites are generally soft-skinned, vividly colored and usually have an undivided body. The jaw feelers are shaped like claws or stilettos. Furthermore, they are equipped with a short, compact pair of jaw buttons and with two scissor-like opposing end links, on which one is claw-shaped. The walking feet are long and plump. Most common mites have two eyes and breathe through trachea. They live freely on plants and on the ground. The six-legged larvae live parasitically on sap and tissue fluid from other arthropods (Arthropoda) and sometimes also predatory of small insects (Insecta) and insect eggs. Blood is only absorbed in exceptional cases. The red velvet mite is one of the best-known running mites.

The red velvet mite is one of the largest and most conspicuous mites and can reach a body length of up to four millimeters. It has an acorn-shaped body that tapers towards the back. The body and legs are covered with small, bright orange-red to reddish hairs, which gives it a velvety shimmer. Hence the name red velvet mite. The hemolymph of the mite is colorless.
Red velvet mite
The hemolymph (body cavity fluid) contains the plasma and blood cells. The coloring is caused by pigments that are embedded in the chitin shell. In addition, the body is flattened dorsally and ventrally. The articulated extremities of the red velvet mite are connected to the idiosoma (actual body) via the coxae (hip joints). They consist of the coxa (hip), trochanter (thigh ring), femur (thigh), genu (knee), tibia (splint), tarsus (foot) and pretarsus (last phalanx or claw). The four articulated pairs of legs are clearly lighter in color than the body. The red velvet mite has no antennae. The front pair of legs is significantly longer and is used as a measuring plate to check where it is going.

On the Gnathosoma = capitulum (head), in which the food for the digestive organs is prepared, are the mouthparts, the paired chelicerae and the paired two-parted palps, of which the somewhat longer basal segment has three bristles and the somewhat shorter apical segment has two solenidia . The scissor-shaped ends of the chelicerae consist of an inner flexible and an outer immobile leg, which are usually serrated on the inner edge. Another component of the gnathosoma is the rutellum, the edges of which often cover a small triangular hypostome (hooked trunk). As a rule, there is a fairly clear sexual dimorphism and the juvenile stages of development: larva, protonymph and tritonymph also differ from the adult red velvet mite. The excretions of the red velvet mite cause asthma and allergies.

distribution

This type of mite is native to large parts of central and southern Europe. It can be found in various habitats such as in the desert, in water, between rocks, in gardens, in flour and in carpets as well as in dry wood, in the litter of mixed forests, moss and leaves, especially in spring it occurs more frequently in beech forests Floor on. You can see the little animals running on the ground all summer. The red velvet mite can even be found in the hair follicles (Folliculus pili), the connective tissue outer hair sheath of the human hair that surrounds the hair root in a sack-shaped manner and that has emerged from the corium, and in the sweat glands. However, the red velvet mite does not sting people because it does not have a sting.

Red velvet mite

nutrition

In the nymph stage, the red velvet mite lives parasitically on other insects, such as the harvester (Opilio parietinus) and feeds on the tissue fluid of their hosts. The nutritional juice consists of liquefied epithelial cells and lymph; blood is only absorbed in exceptional cases. Feeding on the animal host can take several days, then the larva drops to the ground and digs itself into the uppermost soil layers. Here it enters a dormant stage (protonymophe = nymphochrysalis), from which it sheds its skin into a nymph after a few weeks. This in turn develops over the course of a few weeks over a further resting stage (tritonymphe = imagochrysalis) to the imago. Nymphs and adult velvet mites are predatory and feed on soft-skinned insects living on the ground (Insecta) such as harmful mites and fringed winged larvae (Thysanoptera) and small caterpillars and mosquitoes (Nematocera) and grasshoppers (Orthoptera). They also live cannibalically by feeding their conspecifics and their eggs as well as other small mites and also the eggs of insects and snails (Gastropoda) eat. Among other things, they are the natural enemy of phylloxera (Viteus vitifoliae) and are therefore considered to be beneficial. When hunting, it walks around the ground and leaves quite quickly and can eat up to 40 aphids per day.

Reproduction

Red velvet mite

The development of the red velvet mite goes through several stages, namely larva, protonymph and tritonymph. It overwinters from October to March in deeper layers of the fallen leaves and from April to September you can often see the red velvet mite walking on the ground. The male of the red velvet mite lays his sperm cells, also called spermatophores, on small leaves or small petioles by creating a silk trail to the sperm cells. The female crawls along this track and thus arrives at the male's sperm cells. If the male agrees, she takes up the sperm cells through her cloaca. There is no internal fertilization, the fertilization happens indirectly. When another male finds a foreign sperm packet, the male destroys the foreign male's sperm packet and replaces it with his own seed packet. In spring, the female lays her eggs in the top layers of the soil. After a while the reddish six-legged larvae hatch from the eggs and you see the small larvae very often in late summer when they crawl up on grass and bushes. During this time, however, the larvae are predatory and feed on small insects, especially insect eggs, which they locate with their whiskers. Furthermore, the larvae live as external parasites on insects, i.e. they parasitize on these animals by biting into the skin and sucking tissue fluid, this can take several days. The larva then drops to the ground, digs itself into the upper layers of the soil and then goes through two dormant stages or two nymph stages, each of which ends with a molt up to the young red velvet mite with four articulated pairs of legs. Under favorable circumstances, the red velvet mite can live for about a year in nature.

Red velvet mite

ecology

Environmental protection begins in the soil, it is one of our most important resources, a habitat for useful plants and animals. This also includes the red velvet mite, which makes an important contribution to keeping the soil healthy. That is why the presence of the red velvet mite is extremely important for the climate and the vegetation of the soil. The red velvet mite is part of a community of ground arthropods, which plays an important role in the splitting of the soil and the maintenance of the soil structure in the entire ecosystem. Above all, it eats harmful insects and feeds on fungi and bacteria, among other things, and thus stimulates the splitting process of the soil. Furthermore, the red velvet mite is considered very useful by gardeners, as it eats the eggs and larvae of aphids in adulthood.

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See also

  • Main article: the class of Arachnids (Arachnida)
  • Main article: the subclass of Mites (Acari)

Literature and sources

  • Dr. Helgard Reichholf-Riem: Steinbach's nature guide. Insects. With appendix arachnids. Munich: Mosaik Verlag GmbH, Munich 1984. ISBN 3-570-01187-9
  • Ake Sandhall, translated by Dr. Wolfgang Dierl: BLV Determination Book 15. Insects and mollusks. Lower animals and their habitats - arthropods, worms, cnidarians, mollusks, unicellular organisms. BLV Verlagsgesellschaft mbH, Munich Vienna Zurich 1984. ISBN 3-405-11390-3
  • Michael Chinery: Parey's Book of Insects: A Field Guide to European Insects. Translated and edited by Dr. Irmgard Jung and Dieter Jung. Paul Parey publishing house 1987. Hamburg and Berlin. ISBN 3-490-14118-0
  • Heiko Bellmann: Cosmos Atlas Arachnids of Europe. And freshwater crabs, woodlice, millipedes, 2006, Kosmos Verlag ISBN 3440107469
  • Dick Jones, The cosmos spider guide, Frankh, 1990 ISBN 3440061418
  • Hans-Eckhard Gruner, Hans-Joachim Hannemann and Gerhard Hartwich, Urania Animal Kingdom, 7 vols., Invertebrates, Urania, Freiburg, 1994 ISBN 3332005022

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Page categories: running mites