Anelosimus jabaquara | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Chelicerata |
Class: | Arachnida |
Order: | Araneae |
Infraorder: | Araneomorphae |
Family: | Theridiidae |
Genus: | Anelosimus |
Species: | A. jabaquara |
Binomial name | |
Anelosimus jabaquara Levi, 1956 | |
Anelosimus jabaquara is a species of spider found in subtropical, humid, lowland forests in Brazil. Anelosimus jabaquara was first described by Herbert W. Levi in 1956. These spiders cooperate to spin and repair the colonial web, capture prey, and care for the brood. Colony size is small, and the sex ratio is biased towards females.
Adult males are on average smaller than adult females. The mean male cephalothorax length is 1.38 cm, while the mean female cephalothorax length is 1.62 cm. [1] Similar to other Anelosimus species, Anelosimus jabaquara has a minute colulus, three teeth on the anterior margin of the chelicerae and denticles on the posterior. The palpus distinguishes this species from others. The eyes are subequal in size. For males, the carapace and sternum are orange-yellow. The legs are dusky yellow. The abdomen is dusky with dorsal and ventral black bands. [2] For females, the carapace is red, except for black rings around the eyes. The clypeus, chelicerae, and endites are orange, and the sternum and labium are red. The legs are light brown with darker segments on the distal end. The tibiae and femora have dark rings in the middle. The abdomen is dark brown with a dorsal medium band containing black spots. [3]
Anelosimus jabaquara females have one brood per year, and develop through eight instars (stages). Males begin dying soon after copulation; males are not involved in brood care. Spiderlings go through their first instar while inside the egg sac. The spiderlings leave the egg sac in their second instar, however the protective behavior of the female remains. Females feed their spiderlings through regurgitation. This happens until the spiderlings reach the third instar, when they are then able to capture small prey on their own. During the fourth instar, the juveniles of one brood will mix with other broods, capturing prey together in groups. Females begin dying when their brood reaches the 5th instar. [1]
Anelosimus jabaquara reproduction begins in December, and the brood develops from April to October through the care of the females. Each female lays at least one egg sac containing around 27 eggs. The female is able to produce a second sac after abandoning the first. If a female's egg sac is experimentally removed, she will try to steal an egg sac from another female. [1] Female size is positively correlated with clutch size. [4]
The spiders remain under leaves during the hottest hours of the day. During this time, they stay in the resting position with their legs retracted under the cephalothorax. In the evening the spiders leave the leafy area above the web sheet, “the retreat,” in order to renew the silk threads in the web or to position themselves to wait for prey to be captured. During cold and rainy days, the spiders are active throughout the day. Prey capture can happen during the daytime if the prey vibrates enough to attract the spider to leave the retreat to capture the prey. [1]
Eggs sacs are kept in the retreat, guarded by the female. Females guarding their egg sacs move very little and therefore no new silk threads are added to the web during this period. The only times females leave their eggs sacs are to capture prey or copulate. A female that is guarding her egg sac will attack an approaching female by touching the female with its front pair of legs, biting, or pursuing it for a distance. It is hypothesized that the aggressiveness towards other females is used as a means to protect the egg sac or brood from cannibalism. [1]
Adult males, females, and juveniles participate in prey capture. Bigger females attack the prey first by biting the thorax and abdomen of the prey. The smaller females join by biting the appendages or releasing silk threads over the prey. After the prey is immobilized by the females, the males will bite the thorax and abdomen of the prey. Juveniles in their fourth instar will aid by biting the appendages of the prey. Females feed on the prey in groups, or if they prey is small, they break the prey into parts and feed individually. Dead females are eaten by the juveniles or other adult females. [1]
Colony formation usually occurs through the construction of small solitary webs by adult or subadult females, though it may occur through colony budding. Some subadult females found new colonies following solitary dispersal, while others remain in their natal nests. It is argued that emigration is a consequence of a strong selection pressure to maximize food availability before the egg-laying season. Emigrating females are significantly larger and lay larger clutches, while smaller females do not disperse and lay significantly larger eggs. Because emigration requires high-energy expenditure, it is hypothesized that smaller females do not disperse because they are unable to do so successfully. [4]
Colony sizes are small, ranging from 1 to 55 individuals. This suggests that the colonies are the result of one or two females that matured and reproduced. Once the colony is established, females do not leave the web unless it is greatly damaged. The subadult sex ratio is biased towards females with around 1.8 females per male. [1] Anelosimus jabaquara colonies are composed of individuals of the same instar or differing by one molt, except during the overlap of maternal and filial generations. [5]
Web structure is very variable. Webs are usually shaped like a sheet over the branches. The size of the colonial web ranges from 20 cm^2 to 4000 cm^2. The sheet functions as protection from enemies coming from underneath the web. Above the sheet is an area made up of leaves surrounded by loosely spun non-adhesive silk threads, called "the retreat". The spiders commonly hide underneath these leaves during the day. [1]
The katipō is an endangered species of spider native to New Zealand. It is one of many species in the genus Latrodectus, such as the Australian redback, and the North American black widow. The species is venomous to humans, capable of delivering a potentially dangerous bite. It is a small to medium-sized spider, with the female having a round black or brown pea-sized body. Red katipō females found in the South Island and the lower half of the North Island, are always black, and their abdomen has a distinctive red stripe bordered in white. In black katipō females found in the upper half of the North Island, this stripe is absent, pale, yellow, or replaced with cream-coloured blotches. These two forms were previously thought to be separate species. The male is much smaller than the female and quite different in appearance: white with black stripes and red diamond-shaped markings. Katipō are mainly found living in sand dunes close to the seashore. They are found throughout most of coastal New Zealand except the far south and west. Katipō feed mainly on ground dwelling insects, caught in an irregular tangled web spun amongst dune plants or other debris.
Nephila is a genus of araneomorph spiders noted for the impressive webs they weave. Nephila consists of numerous species found in warmer regions around the world, although some species formerly included in the genus have been moved to Trichonephila. They are commonly called golden silk orb-weavers, golden orb-weavers, giant wood spiders, or banana spiders.
Steatoda nobilis is a spider in the genus Steatoda, known in the United Kingdom as the noble false widow, as it superficially resembles and is frequently mistaken for the black widow and other spiders in the genus Latrodectus. It is often referred to as thefalse widow, although "false widow" is a more general term applied to a wider group of species with this resemblance. It is a moderately medically significant spider, with most bites resulting in symptoms similar to a bee or wasp sting. Some bites may cause more significant harm, partly due to pathogenic bacteria from the spiders.
Phidippus audax, the bold jumper or bold jumping spider, is a common species of spider belonging to the genus Phidippus, a group of jumping spiders easily identified by their large eyes and their iridescent chelicerae. Like all jumping spiders, they have excellent stereoscopic vision that aids them in stalking prey and facilitates visual communication with potential mates during courting. Bold jumping spiders are native to North America and have been introduced to Hawaii, Nicobar Islands, Azores, and the Netherlands. They are typically black with a distinct white triangle on their abdomen.
Theridion grallator, also known as the Hawaiian happy-face spider, is a spider in the family Theridiidae that resides on the Hawaiian Islands. T. grallator gets its vernacular name of "Hawaiian happy-face spider" from the unique patterns superimposed on its abdomen, specifically those that resemble a human smiling face. T. grallator is particularly notable because of its wide range of polymorphisms that may be studied to allow a better understanding of evolutionary mechanisms. In addition to the variety of color polymorphisms present, T. grallator demonstrates the interesting quality of diet-induced color change, in which its appearance temporarily changes as it metabolizes various food items.
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Spider behavior refers to the range of behaviors and activities performed by spiders. Spiders are air-breathing arthropods that have eight legs and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms which is reflected in their large diversity of behavior.
A social spider is a spider species whose individuals form relatively long-lasting aggregations. Whereas most spiders are solitary and even aggressive toward other members of their own species, some hundreds of species in several families show a tendency to live in groups, often referred to as colonies.
Cyrtophora citricola, also known as the tropical tent-web spider, is an orb-weaver spider in the family Araneidae. It is found in Asia, Africa, Australia, Costa Rica, Hispaniola, Colombia, and Southern Europe and in 2000, it was discovered in Florida. C. citricola differs from many of its close relatives due its ability to live in a wide variety of environments. In North America and South America, the spider has caused extensive damage to agricultural operations.
Anelosimus eximius is a species of social spider in the genus Anelosimus, native to the Lesser Antilles and the area from Panama to Argentina. Colonies can comprise several thousand individuals.
Rugathodes sexpunctatus is a minute species of spider in the family Theridiidae, the cobweb or tangle-web spiders. This family includes the medically important genus Latrodectus—the widow spiders. The species in the genus Rugathodes are too small to be dangerous to humans. Very little is known about most species in this genus.
Spiders are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms. Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every land habitat. As of November 2023, 51,673 spider species in 136 families have been recorded by taxonomists. However, there has been debate among scientists about how families should be classified, with over 20 different classifications proposed since 1900.
Stegodyphus sarasinorum, also known as the Indian cooperative spider, is a species of velvet spider of the family Eresidae. It is native to India, Sri Lanka, Nepal, and Myanmar. This spider is a social spider that exhibits communal predation and feeding, where individuals live in large cooperatively built colonies with a nest or retreat constructed of silk woven using leaves, twigs, and food carcasses, and a sheet web for prey capture.
Argyrodes elevatus, commonly referred to as dew-drop spider, is part of the family Theridiidae that consists of more than 3,000 species. These spiders are most commonly found in subtropical and tropical regions in South and Central America, as well as southern regions of the United States. One of the key distinguishing characteristics of A. elevatus is its kleptoparasitic behavior through which it primarily procures food for survival. Typically 1 or 2 A. elevatus spiders preside in outer areas of webs built by other species of spiders, although it is possible for up to 45 spiders. There are two main mechanisms by which A. elevatus raid the hub of the host's web to steal insects preyed and wrapped by the host spider. A. elevatus follows an intricate course to the hub of the web to search for prey, using vibrational detection enhanced by laid out threads along the web to find and capture the insect. These spiders are highly efficient, with the theft lasting a maximum of 12 seconds and high success rates. This reliance on a host spider for food has led to adaptations in sleep schedules and alternate food sources to revolve around the host species activity. A. elevatus display a unique courtship routine in which male A. elevatus presents prey wrapped in silk as a nuptial gift to the female spider. The male spider approaches the female, carrying the nuptial gift on its chelicerae while communicating with a distinct courting vibration, followed by copulation. Approximately twenty-four hours after the A. elevatus courtship and copulation series of events, the female spider will lay one to two eggs on the outer regions of the host's web.
Erigone atra is a species of dwarf spider or money spider, in the family Linyphiidae. It is commonly found in North America, Europe, parts of Russia, Central Asia, China, Mongolia, Korea, and Japan. This spider is one of the most common Erigone spiders. E. atra is an important spider for agriculture, as it preys on pests such as aphids which are commonly found on crops. E. atra spiders are aeronautical spiders, as they travel via ballooning. This technique, sometimes referred to as kiting, allows E. atra spiders to traverse large distances and find new habitats when environmental or human stresses create unfit living environments. E. atra is difficult to differentiate from other congeneric species because of their similar sizes and coloring.
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Pardosa pseudoannulata, a member of a group of species referred to as wolf-spiders, is a non-web-building spider belonging to the family Lycosidae. P. pseudoannulata are wandering spiders that track and ambush prey and display sexual cannibalism. They are commonly encountered in farmlands across China and other East Asian countries. Their venom has properties that helps it function as an effective insecticide, and it is, therefore, a crucial pesticide control agent.
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