5/17/2023 0 Comments Spider predators![]() ![]() Males approach females anteriorly females raise their cephalothoraxes to allow males to insert both palpal organs into their genital opening. From there, sperm droplets are drawn into the palpal organ (bulb). In Scytodes, the sperm web is a single thread which typically takes a triangular shape. They do this by drawing a sperm web across their genital openings to accumulate sperm droplets, using their third pair of legs. Upon meeting a female, male spitting spiders fill their palpal organs (accessory reproductive parts on the ends of each pedipalp) with sperm. Location of mates is not based on visual cues and mating usually occurs following an accidental meeting of a male and female. Both sexes produce pheromones, which are detected through contact with chemosensory hairs covering the pedipalps and first pair of legs female mate choice is based on male pheromone production. These spiders are aggressive hunters, so males must approach females cautiously or else be mistaken for prey. Spitting spiders are solitary, interacting only during mating. ( "Spitting spider Scytodes thoracica", 2012 Gertsch, 1949 Guarisco, 1991 Koh, et al., 2009 Larsen, 2005) Reproduction It can take 2-3 years for females to reach maturity. Spiderlings remain with their mothers until their first molts and then disperse to live solitary lives, reaching adulthood after 5-7 molts. Following copulation and egg fertilization, females lay eggs in a cocoon carried under their bodies for 2-3 weeks until eggs hatch. Range length 3.5 to 5.5 mm 0.14 to 0.22 inĪll spiders reproduce sexually, and sex is determined by meiosis.This species exhibits sexual dimorphism, with males typically ranging from 3.5-4 mm in length and females ranging from 4-5.5 mm. ![]() The most anterior portion of the head, below the eyes, projects forwards, past the mandibles. ![]() Their legs, which slowly taper in size as they extend from their bodies, are long with black bands. Spitting spiders have pale yellow bodies with black speckled markings on the cephalothorax, which slightly resemble a lyre. Scytodes are ecribellate, lacking the silk-spinning organ (cribellum) of some other spiders. These spiders produce a gummy substance which is a mix of the two substances and is excreted by their fused chelicerae, which can not be moved separately. These glands are divided into two parts: a smaller, anterior compartment which stores venom and a larger, posterior compartment which contains a mucilaginous substance. Large, well-developed poison glands are located in the cephalothorax. Like all spiders, these two body tagmata (segments) are separated by a thin pedicel (waist-like connector). Their abdomens (which are roughly the same circular shape as the cephalothorax) slope downwards and are only slightly smaller than the cephalothorax. These spiders are also easily identified by their oversized cephalothorax (prosoma), which slopes upward towards their posterior ends. This species has long, thin, legs, and are glabrous (hairless), with the exception of short sensory setae scattered over the body. ( "Spitting spider Scytodes thoracica", 2012) When associated with humans, they are most commonly found in dark corners, cellars, cupboards, and closets of houses and other buildings. Spitting spiders are found in temperate forests. ( "The Spider Book", 1912 Emerton, 1902 Kaston, 1972 "Scytodes thoracica (Spitting spider)", 2011 Ubick, et al., 2005) The presence of this species in more northern climates is attributed to the availability of warm houses and buildings, to which these spiders have adapted. It is unclear which populations are native and which are introduced in these regions. Specimens have also been found in Japan and Argentina. This species is commonly found in the eastern United States, as well as in Britain, Sweden and other European countries. However, spitting spiders are found scattered across neartic, paleartic, and neotropical regions. Members of the genus Scytodes are predominately tropical or subtropical spiders. ![]()
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