Ron's Critter of the Day

TAXONOMY
Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Order: Araneae
Suborder: Araneomorphae (fangs slope towards each other in a pinching action)
Family: Nephilidae

Genus/species; Nephila Clavipes

GENERAL CHARACTERISTICS; Orb-weavers are highly sexually dimorphic. Females grow up to 8 cm (3 in), and are 5 to 6 times larger than males. Adults are mostly yellow with elongated abdomen and long, hairy legs. This spider lives in hot places. The long cylindrical abdomen of the spider may be angled towards the sun to reduce the amount of exposed body surface and thus prevent overheating. The reflective silvery surface of much of the body serves the same purpose.

DISTRIBUTION/HABITAT: These spiders are found from the southeastern United States south through Argentina and Peru. They prefer areas of high humidity and forest areas along trails and clearing edges. N. clavipes is the only member of its genus known in the Western Hemisphere.

DIET IN THE WILD: They feed on small flying insects: beetles, flies, moths, etc., that are captured in their web. After prey is entangled in the web, the spider incapacitates it by biting and then encases it in silk.

REPRODUCTION: Mating is a tricky proposition for orb weaving males. For successful reproduction, males must successfully stimulate females in order to prevent being a meal for their would-be mate, though this unfortunate ending is relatively rare with this species.

MORTALITY/LONGEVITY: Life span: a single season (1 year).

REMARKS: 

•Orb weavers construct webs for defense and capture of prey.

•The silk of the web usually has a golden color that is visible to the naked eye and is the source of the common name.

•The impressive web of most orb weavers is a semi-permanent structure, repaired and rebuilt daily as necessary.

•Spiders from the Nephilia species on display from Madagascar are sometimes released into the Rainforest exhibit. They have settled in a territory behind the exhibit and observable from the spiral ramp. Only females are released as 1) they are much larger than the males and so more visible and 2) the Rainforest biologists have no interest in the uncontrolled breeding of these spiders in the exhibit!

Rainforest Costa Rica CR03

References

California Academy of Sciences docent Rainforest Training Manual 2014

Animal Diversity Web animaldiversity.org/accounts/Nephila_clavipes/

Ron’s flickr  https://www.flickr.com/photos/cas_docents/5389185249/in/album-72157620708938680/

Ron’s WordPress shortlink  http://wp.me/p1DZ4b-1tf