Spider cocoons and their suspension systems as barriers to generalist and specialist predators.

This study tests hypotheses regarding spider cocoons and their suspension systems as barriers to generalist and specialist predators. Evidence presented here suggests that the suspension systems ofMecynogea lemniscata andArgiope aurantia cocoons are effective barriers against small generalists such as ants, but fail to stop large generalists such as birds. Cocoon covers were found to be generally ineffective against generalist predators.

The role of spider cocoons in controlling desiccation.

The abilities of the cocoons of the spiders Mecynogea lemniscata and Argiope aurantia to protect the enclosed egg and spiderling stages from desiccation were investigated in the laboratory under controlled humidities, and in the field under ambient conditions. For M. lemniscata, which has a relatively small clutch (8-30 eggs) and remains in the cocoon for approximately 9-10 months, removal of the cocoon had no effect on water loss from the egg stage, nor did it adversely affect hatching or molting success.

Colony size and parasitoid load in two species of colonial Metepeira spiders from Mexico (Araneae: Araneidae).

While a number of advantages may result from group living, it may also lead to increased levels of attack by parasites because groups may be easier to find. This leads to the prediction that levels of parasitism should increase with colony size. We test this prediction by comparing colony size and parasitoid load for two species of colonial orb-weaving spiders from Mexico, Metepeira (undesc.