- Phonognatha graeffei
Taxobox
name = Leaf curling spider ("Phonognatha graeffei")
image_width =250px
image_caption = "P. graeffei" in retreat
regnum =Animal ia
phylum =Arthropod a
classis =Arachnid a
ordo = Araneae
subordo =Araneomorphae
familia =Tetragnathidae
genus = "Phonognatha"
genus_authority =Keyserling, 1865 (Australia)
diversity_link = List of Tetragnathidae species#Phonognatha
diversity =
subdivision_ranks =
subdivision ="Phonognatha graeffei" commonly called Leaf curling spider, a small
orb spider of familyTetragnathidae , is a common Australian spider found in urban areas as well as woodlands in the North-eastern, Eastern and Southern states. They are distinguished by a curled leaf at the web's centre and form pairs living together in the same leaf though at opposite ends of their shelter, even before mating at maturity. [ [http://www.pressekatalog.de/ARTID/10.1007/s002650050325.html Sexual cohabitation as mate-guarding in the leaf-curling spider Phonognatha grae... aus Behavioral Ecology and Sociobiology: Download ] ] The female creates a separate curled leaf "nursery" hung in foliage nearby.Appearance
The body length of the male is 5 to 6mm and female 8 to 12mm. Males and females look very similar with red-brown legs and body and a cream coloured pattern on their backs. Their bodies are fat and oval shaped with long tapered legs.
[ [http://walkaboutpark.com.au/index.php?id=62 Australia Walkabout Wildlife Park - Wildlife Sanctuary, Sydney Leaf-Curling Spider ] ] [ [http://calamvalecreek.awardspace.com/Pix/Spiders/Phonognatha_graeffei_6.jpgA picture is available here.] ]
Web
The web with its shelter at the centre, is easily identifiable. The leaf curling spider cleverly weaves a leaf or other object into the centre of its web as a hide-away from birds and other predators. Leaves are twisted along their length to form a funnel, (sometimes with a silk wall on one side, if necessary) that the spider can retreat into. They have also been known to use old snail shells and discarded pieces of paper. [ [http://walkaboutpark.com.au/index.php?id=62 Australia Walkabout Wildlife Park - Wildlife Sanctuary, Sydney Leaf-Curling Spider ] ] Although often found clustered in the same area, each spider has its own web.
The leaf curling spider's web is about 30 cm (a foot) across. It is an incomplete circle, being open at the top and fanning downwards. It suspends its curled up dry leaf in shrubs by supporting threads and the fan-like main web radiates out from this leaf, in which the spider hides in retreat with only the tips of its legs visible to feel the vibrations of insects connecting with the web. [ [http://usq.edu.au/spider/find/spiders/113.htm The Find-a-spider Guide - Leaf-curler ] ] It only goes outside its shelter to repair or rebuild its web or if prey falls into the web. It usually rebuilds its web at night. [ [http://www.geocities.com/brisbane_weavers/LeafCurlingSpiders.htm Leaf Curling Spider - Phonognatha graeffei ] ]
Behaviour
The leaf-curling spiders are day-active orb weavers protecting themselves from predators by sitting inside a silk seamed, curled leaf. In "P. graeffei" this leaf is suspended just above the centre of the web, but may be placed higher in other species. Such leaves may be already part curled though many are not, and the spider pulls and silks its leaf into a retreat cylinder, silked shut at the top and open at the hub. [ [http://www.amonline.net.au/factsheets/leaf_curling_spider.htm Araneid leaf-curling spiders ] ] Like other web-weaving spiders, their main food source is flying insects [ [http://walkaboutpark.com.au/index.php?id=62 Australia Walkabout Wildlife Park - Wildlife Sanctuary, Sydney Leaf-Curling Spider ] ] including insects larger than itself. [ [http://www.spiderzrule.com/leafcurl.htm Spiderzrule ] ]
They are noted for their sexual cohabitation and its function in mate-guarding behaviour. [ [http://www.pressekatalog.de/ARTID/10.1007/s002650050325.html Sexual cohabitation as mate-guarding in the leaf-curling spider Phonognatha grae... aus Behavioral Ecology and Sociobiology: Download ] ] This means that the male and female live together in the same curled leaf, each occupying opposite ends of the retreat with the female at the top end.
When disturbed, "P. graeffei" reacts by dropping to the ground and changing colour to blend into the background. [cite journal
title=Ontogenetic change in coloration and web-building behavior in the tropical spider Eriophora fuliginea (Araneae, Araneidae)
author=Graf, B. and Nentwig, W.
year=2001
journal=The Journal of Arachnology
page=29:108, citing Roberts, N.L. 1936 "Color change in the leaf-curling spider ("Araneus wagneri")." Proceedings of the Royal Zoological Society of New South Wales 28-29.]Mating behaviour
This species is unusual among orb-weaving spiders because males cohabit in the leaf retreat with both immature and mature females, mating with the former shortly after the female molts. Male spiders may take up residence nearby, or in the same web as the (often immature) female. Mating takes place as soon as she has her final molt.
According to Babette F. Fahey, M. A. Elgar, [ [http://www.pressekatalog.de/ARTID/10.1007/s002650050325.html "Behavioral Ecology and Sociobiology" (1997)] ] cohabitation may be a form of mate-guarding because resident males challenge rival males that venture onto the web. As well, they consider that the behaviour depends upon the reproductive status of the female since males defending immature females are more aggressive than those defending virgin, adult females. [ [http://www.pressekatalog.de/ARTID/10.1007/s002650050325.html Sexual cohabitation as mate-guarding in the leaf-curling spider Phonognatha grae... aus Behavioral Ecology and Sociobiology: Download ] ]
Males copulate with previously mated females for significantly longer than with virgin females. Females may cannibalise cohabiting males, independently of whether the female has had food and females that cannibalise a single male are not more fertile than non-cannibalistic females. [ [http://www.pressekatalog.de/ARTID/10.1007/s002650050325.html Sexual cohabitation as mate-guarding in the leaf-curling spider Phonognatha grae... aus Behavioral Ecology and Sociobiology: Download ] ]
The female lays its egg sac within a dead leaf, bent over and silked back on itself. This is suspended among foliage well away from the orb web. [ [http://www.amonline.net.au/factsheets/leaf_curling_spider.htm Araneid leaf-curling spiders ] ]
piderlings
Juvenile spiders start off by bending over a small green leaf, eventually graduating to larger dead leaves (or the occasional other lightweight objects) that are hoisted up from the ground on silk lines at night. [ [http://www.amonline.net.au/factsheets/leaf_curling_spider.htm Araneid leaf-curling spiders ] ]
Distribution
The spider is commonly found in open woodland and forest habitats as well as urban and suburban gardens.
"Phonognatha graeffei" and humans
The side-ways action fangs are small and the spider is timid and reluctant to bite. [ [http://www.uq.edu.au/~xxrraven/allspids.html Staff Web Page ] ] Toxicity to humans is unknown [ [http://usq.edu.au/spider/find/spiders/113.htm The Find-a-spider Guide - Leaf-curler ] ] as it is extremely rare for these spiders to bite humans. A bite may result in a localised reaction with pain and swelling, but is not considered dangerous. [ [http://walkaboutpark.com.au/index.php?id=62 Australia Walkabout Wildlife Park - Wildlife Sanctuary, Sydney Leaf-Curling Spider ] ]
imilar species
"P. graeffei" (Australia)
"P. graeffei neocaledonica" (New Caledonia )
"P. guanga" (Philippines )
"P. joannae" (New Caledonia)
"P. melania" (Australia,Tasmania )
"P. melanopyga" (Australia, Tasmania)
"P. pallida" (Western Australia )
"P. vicitra" (India )References
External links
* [http://www.geocities.com/brisbane_weavers/LeafCurlingSpiders.htm closeup pictures showing webs as well]
* [http://zipcodezoo.com/Animals/P/Phonognatha_graeffei.asp Taxonomy and species list]
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