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Celaenia calotoides Rainbow, 1908

Introduction

This article follows the progress, in captivity, of a female of Celaenia calotoides. The spider was kept alive in a "vivarium" after being taken from the northern side of the junction of Fish and Enoggera Creeks, Walton Bridge Reserve, The Gap (GPS: 2726'39.08'S 15257'17.00'E) on 16 July 2009. Overnight between 9pm 20 July and 8am 21 July 2009 she produced an egg case while in a bug-viewer and was then moved to a makeshift cage for further observations. On Wednesday, 22 July 2009 two more egg cases were taken from the site where she was found. On 31 July, while being checked, the spider escaped into the yard at 917 Waterworks Road, The Gap. Two of the egg cases were taken by the Queensland Museum for rearing, while the freshly produced egg case was retained for observation.

Description

Celaenia are the "Bird Dropping Spiders" notable for feeding on moths attracted by pheremones released by the adult spiders. Another more commonly observed species in Celaenia is C. excavata (L. Koch, 1867).

The female from Walton Bridge Reserve, with a body length about 6mm front to rear, but taller (about 8mm in height) appeared fat, mostly grey blue with some brown, and very cryptic, at first glance not appearing spider-like at all.

At rest, on a silk strand tethered to foliage, it resembled (possibly mimicking) a pupa of a butterfly in the Swallowtail family (Papilionidae), itself disguised as a piece of stem or a bent branchlet.

The spider's face between large tucked-away legs was pointy (strongly narrowed carapace) with small eyes. The abdomen was brown-grey with a blue-silver section on the front, and high peaked wings like miniature church spires. All over the front of the abdomen there were yellow tipped bumps (tubercles) and a faint white beehive pattern made of small white hairs. The rear section of the abdomen was mostly grey, smoother, and very fat with eggs. (See photos below.) Hickman notes the gravid females can look very different from non-gravid ones: "Female specimens of one and the same species often appear very different according as to whether they are gravid or non-gravid. When the abdomen is distended with eggs, tubercles and folds on the surface tend to become smoothed out." (Hickman 1971)

The habitat where the spider was taken was just on the fringe of dry rainforest merging with dry sclerophyl. The plant community included mostly Jagera pseudorhus with some Acacia, Flindersia, Callistemon/ Melaleuca salignus, Grey Gum. Some of the plants were revegetation plantings some were remnant local native species. The area was weedy, but becoming less so due to bushcare activity, the main weeds being Ochna, Climbing Asparagus Fern, Cape Honeysuckle and Panic Grass.

Egg case produced while still in bug viewer

Helen Smith (Australian Museum) suggested putting the spider in a cage with foliage in the hope she would give birth, as she looked very gravid, an observation Robert Raven confirmed (Smith, Raven, pers. corr.). Preparing to do this on Tuesday 21 July 2009, we observed the spider had already produced a brown egg case about 6mm in diameter while still inside her present container, a bug viewer about 12cm in diameter, 18cm tall, where she had been kept along with a few large leaves of Alectryon tomentosus. The spider was resting, hanging onto the egg case. The egg case was attached by silk to one of the Alectryon leaves near the top of the chamber. It had been produced between the hours of 9pm Monday 20 July and 9am Tuesday 21 July 2009. This egg case will be watched closely as there have never been observations recording the length of time between the production of the egg case and the emergence of young, the previous egg cases being collected from the wild.

Helen subsequently suggested we check the location where the spider was taken, in case more egg cases could be found. Indeed, at the location where the spider was found we discovered two more egg cases. They were attached to the leaves on the lower branches of a young Hickory Wattle (Acacia disparrima) about 40cm from the main trunk and 2m above the ground. We installed these extra egg cases and the spider and her egg sac inside a new, larger container made from a tray with slits on one side, sealed on the other with mosquito netting. The female, having given birth, appeared much slimmer. (See photos below).

Feeding habits (Hickman 1971)

Hickman, 1971 reports of Celaenia spp. "the spider does not spin a web for the capture of prey. Its food appears to consist entirely of night-flying moths." "During the day the spider sits motionless with its legs folded close to the body. It makes no attempt to capture prey and, if touched, shows little tendency to move. At night, however, it often rests with the first and second pairs of legs extended or with the legs in the same attitude it may hang suspended on a thread. If a moth flutters near enough, it is at once seized and held securely against the rows of spines below the femora."

Hickman could not induce either the adults or the young to eat flies. Robert Raven reports, however, that the young, who are too small to deal with moths, feed on fruit flies attract with fruit fly pheremones.

Spider lost in yard

During an inspection to check on the spider's well being the egg cases spider jerked violently by her silk into the nearby leaf litter, effectively mingling with a pile of debris every bit of which was a perfect match for a spider who disguises herself as a bit of broken twig. Searches proved fruitless. Subsequently, the two egg cases from the wild were accepted by Queensland Museum for observation and rearing, while the egg case produced 21/22 July was retained for observation.

PHOTOGRAPHS

Female, very gravid, facing, legs spread slightly


Celaenia distincta
Photo: Robert Whyte

Female, very gravid, from side


Celaenia distincta
Photo: Robert Whyte

Female, very gravid, at rest, disguised


Celaenia distincta
Photo: Robert Whyte

Female, very gravid, closeup from above


Celaenia distincta
Photo: Robert Whyte

Female, very gravid, underneath, from behind


Celaenia distincta
Photo: Robert Whyte

Female, very gravid, underneath, showing legs


Celaenia distincta
Photo: Robert Whyte

Egg case produced in captivity


Observed on the morning of 21 July 2009.

Celaenia distincta egg sac on Alectryon
Photo: Robert Whyte

Two more egg cases retrieved from the wild


Celaenia distincta egg sacs on Acacia disparrima
Photo: Robert Whyte

Female after having produced egg case, from above


Celaenia distincta female
Photo: Robert Whyte

Female after having produced egg case, with egg cases


Celaenia distincta female
Photo: Robert Whyte

Female after having produced egg case, closeup


Celaenia distincta female
Photo: Robert Whyte

Makeshift vivarium


Vivarium
Photo: Robert Whyte

Closeup of face and eyes


Celaenia calotoides female

Oblique view, warm light, on flat surface


Celaenia calotoides female
Photo: Robert Whyte

Oblique view, tucked up, on twig


Celaenia calotoides female
Photo: Robert Whyte

Side view on twig


Celaenia calotoides female
Photo: Robert Whyte

South Australian example


Celaenia calotoides female
Photo: David Hirst

David Hirst SA Museum sent this picture with the observation that C. calotoides in South Australia were seen on all sorts of vegetation and even the outside eaves of houses. Their arrangement of egg cases is not restricted to a string as described in Rainbow, but can be clustered. This photo shows the female in typical position on the cluster.

References


This article by Robert Whyte relied on the generosity of many experts, in particular thanks go to: Dr Robert Raven, Queensland Museum for advice on identification; Dr Helen Smith, Australian Museum, for information on Celaenia biology and keeping spiders; Dr David Hirst, SA Museum for his photograph and advice on SA examples; and for advice and encouragement Dr Ron Atkinson and Dr Greg Anderson.

Hickman, V. V. Three Tasmanian spiders of the genus Celaenia Thorell (Araneida) with notes on their biology. Pap. Proc. R. Soc. Tasmania 105: 75-82. Submitted 1970, published 1971.

Platnick, Norman I. The World Spider Catalog, Version 10.0 2000 - 2009 American Museum of Natural History.

 

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