The only known observations of mating behavior occured in a laboratory environment where there was only one female and one male to work with. It is assumed that the mating system in nature is similar to, if not the same as, that observed in the laboratory environment. However, scientists are not sure whether these animals are monogamous or polygamous.
Laboratory studies of mating behavior show that males visit female webs, and use a 4-tap rhythmical-pattern drumming on the silk of the web. After several cautious approaches, males approach females, become strapped down with silk from the female, and copulate. Mating may take 35 minutes or more. After mating, the male remains on the female's web. Mating may occur repeatedly.
While facing down near the center of her web, the female produces an egg sac with 100 to 260 eggs. She deposits the sac on the underside of leaves near the nest, then dies. The eggs must hatch and survive without parental care over the winter, then spiderlings disperse in the spring when they are able to spin webs and produce eggs (females) or fertilize eggs (males) on their own. Both males and females reach maturity within 2 to 5 weeks of age.
Breeding season: Breeding occurs during winter.
Range number of offspring: 100 to 260.
Range age at sexual or reproductive maturity (female): 2 to 5 weeks.
Range age at sexual or reproductive maturity (male): 2 to 5 weeks.
Key Reproductive Features: semelparous ; seasonal breeding ; sexual ; fertilization (External )
All parental care in crablike orb weavers occurs before the young hatch. After the female lays an egg mass, she dies. The eggs are left to hatch and the spiderlings to disperse. In order to protect and feed the young in their egg and larval stages, the female constructs an egg case. In nature, the case is constructed on the bottom and sometimes the top of the leaves on trees where the web is located, but not on limbs or trunks of trees. The case is constructed first from an ovate egg sheet made of loosely woven fine threads which are firmly attached to the lower leaf surface with strong attachment disks. The eggs are distributed upward on the platform in a long, ovate mass. The female covers the egg mass with a loose, spongy, tangled mass of yellow and white threads, fastened with the same type of disks used before. Another covering is made when the female moves along the mass, loosely covering it with several dozen coarse, rigid, dark green threads. These threads form a distinct longitudinal line on the case. The final cover is a net-like canopy, spun over the mass and attached to a leaf. Hatched spiderlings take a few days to learn how to move correctly, and under undisturbed, natural conditions do not disperse from the case for 2 to 5 weeks.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female)
- Milne, L., M. Milne. 1980. The Audubon Society Field Guide Series. New York: Alfred A. Knopf Inc..
- Muma, M. 1971. Biological and Behavioral notes on *Gasteracantha cancriformis* (Arachnida: Araneidae). Florida Entemol., 54: 345-351.