page_title: Opiliones
section_title: Behavior
hierarchical_section_title: Opiliones / Behavior
caption_attribution_description: Deutsch: Weberknecht mit Milbenbefall, fotografiert im August 2004 von soebe Titel: Weberknecht mit Milbenbefall (Platybunus sp.??), Foto: , 17.08.2004 Beschreibung: Bei einem Kurzurlaub im Riesengebirge wollte ich bei einer Wanderung von Špindlerův Mlyn zur Elbquelle einige Langfühlerschrecken knipsen. Dabei fiel mir dieser bemitleidenswerte Weberknecht auf, der von etlichen Milben befallen ist, die sich parasitär von ihm ernähren. Aug 2004 by Soebe English: harvestman suffering from mite infestation. Description: With a short break in the Giant Mountains I wanted a hike Spindleruv Mlyn of Elbquelle to shoot some long horned crickets. I encountered this pitiful harvestman afflicted by a number of mites that parasitically feed on him.
context_page_description: The Opiliones are an order of arachnids colloquially known as harvestmen, harvesters, or daddy longlegs. As of April 2017, over 6,650 species of harvestmen have been discovered worldwide, although the total number of extant species may exceed 10,000. The order Opiliones includes five suborders: Cyphophthalmi, Eupnoi, Dyspnoi, Laniatores, and Tetrophthalmi, which were named in 2014.
  Representatives of each extant suborder can be found on all continents except Antarctica.
  Well-preserved fossils have been found in the 400-million-year-old Rhynie cherts of Scotland, and 305-million-year-old rocks in France, which look surprisingly modern, indicating that their basic body shape developed very early on, and, at least in some taxa, has changed little since that time.
  Their phylogenetic position within the Arachnida is disputed; their closest relatives may be the mites or the Novogenuata. Although superficially similar to and often misidentified as spiders, the Opiliones are a distinct order that is not closely related to spiders. They can be easily distinguished from long-legged spiders by their fused body regions and single pair of eyes in the middle of the cephalothorax.
context_section_description: Many species are omnivorous, eating primarily small insects and all kinds of plant material and fungi, and a few have also been found to prey on amphibians. Some are scavengers, feeding upon dead organisms, bird dung, and other fecal material. Such a broad range is unusual in other arachnids, which are typically pure predators. Most hunting harvestmen ambush their prey, although active hunting is also found. Because their eyes cannot form images, they use their second pair of legs as antennae to explore their environment. Unlike most other arachnids, harvestmen do not have a sucking stomach or a filtering mechanism. Rather, they ingest small particles of their food, thus making them vulnerable to internal parasites such as gregarines.
  Although parthenogenetic species do occur, most harvestmen reproduce sexually. Mating involves direct copulation, rather than the deposition of a spermatophore. The males of some species offer a secretion (nuptial gift) from their chelicerae to the female before copulation. Sometimes, the male guards the female after copulation, and in many species, the males defend territories. In some species, males also exhibit post-copulatory behavior in which the male specifically seeks out and shakes the female's sensory leg. This is believed to entice the female into mating a second time.
  The females lay eggs from an ovipositor shortly after mating to several months later. Some species build nests for this purpose. A unique feature of harvestmen is that some species practice parental care, in which the male is solely responsible for guarding the eggs resulting from multiple partners, often against egg-eating females, and cleaning the eggs regularly. Depending on circumstances such as temperature, the eggs may hatch at any time after the first 20 days, up to about half a year after being laid. Harvestmen variously pass through four to eight nymphal instars to reach maturity, with most known species having six instars.
  Most species are nocturnal and colored in hues of brown, although a number of diurnal species are known, some of which have vivid patterns in yellow, green, and black with varied reddish and blackish mottling and reticulation.
  Many species of harvestmen easily tolerate members of their own species, with aggregations of many individuals often found at protected sites near water. These aggregations may number 200 individuals in the Laniatores, and more than 70,000 in certain Eupnoi. Gregarious behavior is likely a strategy against climatic odds, but also against predators, combining the effect of scent secretions, and reducing the probability of any particular individual being eaten.
  Harvestmen clean their legs after eating by drawing each leg in turn through their jaws.
caption: Mites parasitising a harvestman
exif: {}