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Leucauge Mariana
''Leucauge mariana'' is a long-jawed orb weaver spider, native to Central America and South America. Its web building and sexual behavior have been studied extensively. Males perform several kinds of courtship behavior to induce females to copulate and to use their sperm. A particularly unusual feature of sex in ''L. mariana'' is the formation of mating plugs during copulation. These masses sometimes block the access of subsequent males to the female’s genitalia and can prevent copulations. Unlike other species, ''L. mariana'' forms the mating plug from materials contributed by both the female and the male; the male alone cannot make a functional plug. Most mating plugs in other animals are typically viewed as a male tactic used to increase his chances of paternity, without participation of the female. Female participation in creating a mating plugs, and her presumed benefit from them, have led to multiple studies of sexual selection on the sexual behavior of ''L. mariana''. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-jawed Orb Weaver
Long-jawed orb weavers or long jawed spiders (Tetragnathidae) are a family of Araneomorphae, araneomorph spiders first described by Anton Menge in 1866. They have elongated bodies, legs, and chelicerae, and build small orb webs with an open hub with few, wide-set radii and spirals with no signal line or retreat. Some species are often found in long vegetation near water. Systematics , the World Spider Catalog accepts the following extant genera: *''Alcimosphenus'' Simon, 1895 — Caribbean *''Allende_(spider), Allende'' Álvarez-Padilla, 2007 — Chile, Argentina *''Antillognatha'' Bryant, 1945 — Hispaniola *''Atelidea'' Simon, 1895 — Sri Lanka *''Azilia'' Keyserling, 1881 — United States, Panama, South America, Caribbean *''Chrysometa'' Simon, 1894 — South America, Central America, Mexico, Caribbean *''Cyrtognatha'' Keyserling, 1881 — South America, Central America, Caribbean, Mexico *''Dianleucauge'' Song & Zhu, 1994 — China *''Diphya'' Nicolet, 1849 — Asia, Sou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abdomen (insect Anatomy)
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. The area occupied by the abdomen is called the abdominal cavity. In arthropods it is the posterior tagma of the body; it follows the thorax or cephalothorax. In humans, the abdomen stretches from the thorax at the thoracic diaphragm to the pelvis at the pelvic brim. The pelvic brim stretches from the lumbosacral joint (the intervertebral disc between L5 and S1) to the pubic symphysis and is the edge of the pelvic inlet. The space above this inlet and under the thoracic diaphragm is termed the abdominal cavity. The boundary of the abdominal cavity is the abdominal wall in the front and the peritoneal surface at the rear. In vertebrates, the abdomen is a large body cavity enclosed by the abdominal muscles, at front and to the sides, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orb-weaver Spider
Orb-weaver spiders are members of the spider family Araneidae. They are the most common group of builders of spiral wheel-shaped webs often found in gardens, fields, and forests. The English word "orb" can mean "circular", hence the English name of the group. Araneids have eight similar eyes, hairy or spiny legs, and no stridulating organs. The family has a cosmopolitan distribution, including many well-known large or brightly colored garden spiders. With 3,108 species in 186 genera worldwide, the Araneidae comprise the third-largest family of spiders (behind the Salticidae and Linyphiidae). Araneid webs are constructed in a stereotypical fashion, where a framework of nonsticky silk is built up before the spider adds a final spiral of silk covered in sticky droplets. Orb webs are also produced by members of other spider families. The long-jawed orb weavers (Tetragnathidae) were formerly included in the Araneidae; they are closely related, being part of the superfamily Arane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leucauge Mariana Ventral View PC030104BESTVENT
''Leucauge'' () is a spider genus of long-jawed orb weavers, with over 160 species and fully pantropical distribution. The genus was first documented in Scottish zoologist Adam White's 1841 ''Description of new or little known Arachnida''. Charles Darwin had suggested the name of the genus and collected the first specimen in May 1832, later named ''L. argyrobapta''. A vague description and the loss of the only specimen left the genus ill-defined. ''Leucauge'' developed into something of a wastebasket taxon containing 300 loosely related species, until research in the year 2010 resolved ''L. argyrobapta'' as a synonym of the quite common '' L. venusta'' and allowed revision and reclassing of the genus. However, a 2018 paper restored ''Leucauge argyrobapta'' as a separate species. The body and leg shapes and the silver, black and yellow markings of ''Leucauge'' females make identification of the genus relatively easy. They have two rows of long, slender curved hairs on the femu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Cannibalism
Sexual cannibalism is when an animal, usually the female, cannibalizes its mate prior to, during, or after copulation.Polis, G.A. & Farley, R.D. Behavior and Ecology of Mating in the journal of Arachnology 33-46 (1979). It is a trait observed in many arachnid orders and several insect orders. Several hypotheses to explain this seemingly paradoxical behavior have been proposed. The adaptive foraging hypothesis,Blamires, S.J. Nutritional implications for sexual cannibalism in a sexually dimorphic orb web spider. Austral Ecology 36, 389-394 (2011). aggressive spillover hypothesisArnqvist, G. Courtship behaviour and sexual cannibalism in the semi-aquatic fishing spider, DOLOMEDES FIMBRIATUS (CLERCK) (ARANEAE: PISAURIDAE).pdf. The journal of Arachnology 20, 222-226 (1992). and mistaken identity hypothesisGould, S. Only his wings remained. Natural History 93, 10-18 (1984). are among the proposed hypotheses to explain how sexual cannibalism evolved. This behavior is believed to have evolve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermatheca
The spermatheca (pronounced plural: spermathecae ), also called receptaculum seminis (plural: receptacula seminis), is an organ of the female reproductive tract in insects, e.g. ants, bees, some molluscs, oligochaeta worms and certain other invertebrates and vertebrates. Its purpose is to receive and store sperm from the male or, in the case of hermaphrodites, the male component of the body. Spermathecae can sometimes be the site of fertilization when the oocytes are sufficiently developed. Some species of animal have multiple spermathecae. For example, certain species of earthworms have four pairs of spermathecae—one pair each in the 6th, 7th, 8th, and 9th segments. The spermathecae receive and store the spermatozoa of another earthworm during copulation. They are lined with epithelium and are variable in shape: some are thin, heavily coiled tubes, while others are vague outpocketings from the main reproductive tract. It is one of the many variations in sexual reproduct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epigynum (spider)
The epigyne or epigynum is the external genital structure of female spiders. As the epigyne varies greatly in form in different species, even in closely related ones, it often provides the most distinctive characteristic for recognizing species. It consists of a small, hardened portion of the exoskeleton located on the underside of the abdomen, in front of the epigastric furrow and between the epigastric plates. Functions The primary function of the epigyne is to receive and direct the palpal organ of the male during copulation. The various specific forms of epigynes are correlated, in each case, with corresponding specific differences in the palpus of the male. This specialization prevents individuals of different species from mating. The epigyne covers or accompanies the openings of the spermathecae, which are pouches for receiving and retaining sperm. Frequently, the openings of the spermathecae are on the outer face of the epigyne and can be easily seen. A secondary functio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pedipalp
Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") and anterior to the first pair of walking legs. Overview Pedipalps are composed of six segments or articles: the coxa, the trochanter, the femur, the short patella, the tibia, and the tarsus. In spiders, the coxae frequently have extensions called maxillae or gnathobases, which function as mouth parts with or without some contribution from the coxae of the anterior legs. The limbs themselves may be simple tactile organs outwardly resembling the legs, as in spiders, or chelate weapons ( pincers) of great size, as in scorpions. The pedipalps of Solifugae are covered in setae, but have not been studied in detail. Comparative studies of pedipalpal morphology may suggest that leg-like pedipalps are primitive in arachnids. At present, the only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chelicerae
The chelicerae () are the mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated fangs, or similarly to pincers. Some chelicerae, such as those found on nearly all spiders, are hollow and contain (or are connected to) venom glands, and are used to inject venom into prey or a perceived threat. In ''Pisaurina mira'', also known as the nursery web spider, the chelicerae are utilized to snatch the prey once it becomes within reach, facilitating the "sit-and-wait ambush predator" behavior. Both pseudoscorpions and harvestmen have structures on their chelicerae that are used for grooming (papillae in pseudoscorpions, cheliceral teeth in Opiliones). Types Chelicerae can be divided into three kinds: jackknife chelicerae, scissor chelicerae, and 3-segmented chelate chelicerae. Jackknife chelicerae The jackknife chelicera is subchelate (with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chelicerae
The chelicerae () are the mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated fangs, or similarly to pincers. Some chelicerae, such as those found on nearly all spiders, are hollow and contain (or are connected to) venom glands, and are used to inject venom into prey or a perceived threat. In ''Pisaurina mira'', also known as the nursery web spider, the chelicerae are utilized to snatch the prey once it becomes within reach, facilitating the "sit-and-wait ambush predator" behavior. Both pseudoscorpions and harvestmen have structures on their chelicerae that are used for grooming (papillae in pseudoscorpions, cheliceral teeth in Opiliones). Types Chelicerae can be divided into three kinds: jackknife chelicerae, scissor chelicerae, and 3-segmented chelate chelicerae. Jackknife chelicerae The jackknife chelicera is subchelate (with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod Cuticle
The cuticle forms the major part of the integument of the Arthropoda. It includes most of the material of the exoskeleton of the insects, Crustacea, Arachnida, and Myriapoda. Morphology In arthropods, the integument, the external "skin", or "shell", is the product of a single layer of ectodermal epithelium. That layer is attached to the external or distal surface of the deepest layer, the non-cellular internal membrane of the integument. That non-cellular membrane is called the basement membrane. The layer of epithelium on the basement membrane produces the cuticle, which begins as a tough, flexible layer of chitin. Such thin, flexible chitin is the major structural part of the integument where flexibility is necessary, such as in bodily parts that must stretch to contain accumulated liquids, or that form joints between rigid parts of the exoskeleton. In other parts of the cuticle the function of the integument demands more rigid materials, such as armoured regions or the biting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molt
In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer layer or covering), either at specific times of the year, or at specific points in its life cycle. In medieval times it was also known as "mewing" (from the French verb "muer", to moult), a term that lives on in the name of Britain's Royal Mews where the King's hawks used to be kept during moulting time before becoming horse stables after Tudor times. Moulting can involve shedding the epidermis (skin), pelage (hair, feathers, fur, wool), or other external layer. In some groups, other body parts may be shed, for example, the entire exoskeleton in arthropods, including the wings in some insects. Examples In birds In birds, moulting is the periodic replacement of feathers by shedding old feathers while producing new ones. Feathers are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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