The pantropical spider family Deinopidae includes 60 species (Platnick (2013), the distribution of one of which (Deinopis spinosa) extends northward to subtropical regions of the southeastern United States.Members of this family of nocturnal spiders, which have elongated abdomens and a distinctive web architecture, are often known as ogre-faced spiders or net-casting spiders. The first name derives from the closely spaced, extremely large posterior median eyes that are characteristic of the pantropical genus Deinopus (members of the other deinopid genus, Menneus, which is found mainly in the Old World tropics [specifically, Africa and Australasia], have posterior median eyes that are not so large and are spaced farther apart). The second name, "net-casting spiders", refers to the remarkable prey capture behavior displayed by deinopids in which the spider grasps the corners of its small web with its four anterior (front) tarsi and lunges (actually, drops) toward its prey to envelop it with the extremely extensible web. After each successful strike (and often after an unsuccessful strike) the web is destroyed and must be rebuilt. Deinopid webs and prey capture behavior have been studied by numerous authors (see references in Coddington et al. 2012).
Blest and colleagues have investigated the visual physiology of deinopids (e.g., Blest and Land 1977; Blest 1978; see Coddington et al. 2012 for additional references).
Egg sacs are hard, brown spherical balls about the size of a pea. Tropical species bury their egg sacs in moist leaf litter, where the hard casing presumably rots in time to permit the spiderlings to escape (Coddington 2005).
For many decades, the genus name Deinopis was spelled (without good justification) as Dinopis and the family name Deinopidae was spelled Dinopidae (Coddington 2005). The family Deinopidae was long thought to be closely related to the Uloboridae, a belief that has been supported by modern phylogenetic analyses (Coddington 2005 and references therein).
(Coddington 2005 and references therein; Coddington et al. 2012 and references therein; Bradley 2013)
Deinopidae, also known as net casting spiders, is a family of cribellate[1] spiders first described by Carl Ludwig Koch in 1850.[2] It consists of stick-like elongated spiders that catch prey by stretching a web across their front legs before propelling themselves forward. These unusual webs will stretch two or three times their relaxed size, entangling any prey that touch them. The posterior median eyes have excellent night vision, allowing them to cast nets accurately in low-light conditions. These eyes are larger than the others, and sometimes makes these spiders appear to only have two eyes. Ogre-faced spiders (Deinopis) are the best known genus in this family. The name refers to the perceived physical similarity to the mythological creature of the same name. This family also includes the humped-back spiders (Menneus).[3]
They are distributed through tropics worldwide from Australia to Africa and the Americas. In Florida, Deinopis often hangs upside down from a silk line under palmetto fronds during the day. At night, it emerges to practice its unusual prey capture method on invertebrate prey. Its eyes are able to gather available light more efficiently than the eyes of cats and owls, and are able to do this despite the lack of a reflective layer (tapetum lucidum); instead, each night, a large area of light-sensitive membrane is manufactured within the eyes, and since arachnid eyes do not have irises, it is rapidly destroyed again at dawn.[4][5]
Two genera formerly included in this family, Avella O. P-Cambridge, 1877 and Avellopsis Purcell, 1904, are now placed in Menneus. As of November 2021, the World Spider Catalog accepts the following genera:[3]
Deinopidae, also known as net casting spiders, is a family of cribellate spiders first described by Carl Ludwig Koch in 1850. It consists of stick-like elongated spiders that catch prey by stretching a web across their front legs before propelling themselves forward. These unusual webs will stretch two or three times their relaxed size, entangling any prey that touch them. The posterior median eyes have excellent night vision, allowing them to cast nets accurately in low-light conditions. These eyes are larger than the others, and sometimes makes these spiders appear to only have two eyes. Ogre-faced spiders (Deinopis) are the best known genus in this family. The name refers to the perceived physical similarity to the mythological creature of the same name. This family also includes the humped-back spiders (Menneus).
They are distributed through tropics worldwide from Australia to Africa and the Americas. In Florida, Deinopis often hangs upside down from a silk line under palmetto fronds during the day. At night, it emerges to practice its unusual prey capture method on invertebrate prey. Its eyes are able to gather available light more efficiently than the eyes of cats and owls, and are able to do this despite the lack of a reflective layer (tapetum lucidum); instead, each night, a large area of light-sensitive membrane is manufactured within the eyes, and since arachnid eyes do not have irises, it is rapidly destroyed again at dawn.
