Orb-Weaving Spiders of the Night

About 30,000 species of spiders have been recognized and many more are likely to be discovered. Each has adapted to a specific niche – the habitat it lives in, what it eats, and how it gets its meals. When we think of spiders, we may think of spider webs – but not all spiders build webs. We might also think of the nature of the habitat where and when they are found. Their food, how they obtain it, and the nature of their habitats vary – and it is that variation that has allowed development of the great diversity of spider species. On this week’s Wild Things I will use two Florida spider species to illustrate some of the nature of spider diversity. The large Tropical Orbweaver is primarily nocturnal, constructs its web anew each night, feeds on moths and other large flying insects, then eats the web before morning, and hides in curled up leaves by day. The much smaller Spiny-backed Orbweaver can be found in its web day and night, although it too may eat its web and construct a new one each day. This spider feeds on smaller insects, and females have sharp red spines that might deter potential predators. Each species uses a different habitat – the Tropical Orbweaver needs large open areas in woodlands for its large web; the Spiny Orb weaver makes a smaller web among smaller branches and occasionally builds a web near a porch light – thus taking advantage of insects attracted by the light.