''Argiope protensa'', commonly known as the tailed grass spider or teardrop spider, is a species of spider in the orb weaver family,

Araneidae 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 ...

. This species is fairly common and widespread in

Australasia Australasia is a subregion of Oceania, comprising Australia, New Zealand (overlapping with Polynesia), and sometimes including New Guinea and surrounding islands (overlapping with Melanesia). The term is used in a number of different context ...

, but like many spider species, little is known of its ecology, biology, or life history.

Description

''Argiope protensa'' is a slender, medium-sized spider, reaching a body length of 13 – 25 mm. Its

abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

is distinctively elongate, tapering to a long “tail” extending beyond the ventrally-positioned

spinneret A spinneret is a silk-spinning organ of a spider or the larva of an insect. Some adult insects also have spinnerets, such as those borne on the forelegs of Embioptera. Spinnerets are usually on the underside of a spider's opisthosoma, and ar ...

s — though immature and/or male specimens may not clearly show this characteristic. The

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

abdomen has on each side a finely pubescent strip of short, silvery hairs, which become sparse closer to the apex. Four to six pairs of weakly indented spots border the variably-coloured, hairless medial line; similar hairless dark strips run along the sides of the abdomen. Ventrally, the abdomen is dark and sparsely-haired; two pale stripes run longitudinally down its entire length to the apex. The

cephalothorax The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cepha ...

makes up about a quarter of the body length, and is covered in silvery-grey hairs on its dorsal surface. Colouration of the legs can vary between individuals; some are almost uniformly grey-brown, while others have strongly contrasting bands of dark and light colour along their lengths. In descending order, the relative leg lengths are 1, 2, 4, 3. In Australia, ''Argiope protensa'' can be distinguished from ''A. probata'' (the only other '' Argiope'' species with a similarly-shaped abdomen) by examining morphological characteristics of the

epigyne 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. ...

. The tailed grass spider's web is variable, usually quite small (especially compared to those of other ''Argiope'' species), and may be constructed close to the ground and oriented on a plane anywhere between vertical and horizontal. A 2022 analysis of 262 photographs showing 124 different tailed grass spider webs across Australia and New Zealand showed 38.7% contained a structure known as a stabilimentum, the purpose of which is yet to be determined. Argiope protensa adult female NZ dorsal 2.jpg, Adult female ''Argiope protensa'' dorsal view Argiope protensa adult female NZ ventral.jpg, Adult female ventral view

Distribution

''Argiope protensa'' is recorded from Australia, New Zealand, New Caledonia and New Guinea. It is considered native to New Zealand, believed to have arrived from Australia by natural means; scrutiny of early collection records and/or comparative genetic analysis would be required to confirm this and estimate a time of first arrival. A 2014 study analysed changes in spider assemblage composition of Australian grasslands across a 900 km environmental gradient, and found a strong positive relationship between ''A. protensa'' and taller vegetation with high intra-tussock density.

Life cycle

The length of the tailed grass spider’s life cycle is unknown but, like similar species, probably lasts no more than two years. Females reach maturity in midsummer, and produce cup-shaped egg masses in the late summer. It is unknown when the young hatch from their eggs.

Ballooning Ballooning may refer to: * Hot air ballooning * Balloon (aeronautics) * Ballooning (spider) * Ballooning degeneration, a disease * Memory ballooning In computing, memory ballooning is a technique that is used to eliminate the need to overcommit ...

is probably an important mechanism by which the young disperse to new habitats, and is likely how this species reached New Zealand from Australia.

Interactions

As an orb-weaving spider, ''Argiope protensa'' is a generalist predator and will consume any invertebrates it can capture and subdue, though some preferential selection of prey may occur, as seen in other araneid spiders. Prey is usually restrained by wrapping with broad swathes of dense

silk Silk is a natural fiber, natural protein fiber, some forms of which can be weaving, woven into textiles. The protein fiber of silk is composed mainly of fibroin and is most commonly produced by certain insect larvae to form cocoon (silk), c ...

, which is a common behaviour in other species in this genus.

Further information

''Argiope protensa'' was first described from Australia by L. Koch in 1872; in 1885 it was also described as ''Epeira attenuata'' by Urquhart from specimens collected in New Zealand. Several other synonyms exist from different collection locations. Taxonomic confusion continued until 1971, when Chrysanthus confirmed that specimens collected from New Guinea matched Koch’s original description; in 1983 Levi agreed that similarities in genital morphology suggested many of the previously-described Australasian species were synonyms. In 2017, phylogenetic analysis by Wheeler et al. confirmed the placement of ''Argiope'' within the family Araneidae.

Gallery

3.Argiope protensa - dorsal.jpg, ''Argiope protensa'' dorsal view 1.Argiope protensa - ventral.jpg, Ventral view — note strong bands of colour on legs 2.Argiope protensa - side.jpg, Side view Argiope protensa subadult female.jpg, Subadult female — note yellow medial line

References

External links

*
''Argiope protensa''
{{Taxonbar, from=Q1309229 protensa Spiders of New Guinea Spiders described in 1872 Spiders of New Zealand Spiders of Australia Spiders of New Caledonia