The genus Latrodectus, commonly known as the black widow spider, is recognized globally for its potent venom and distinctive appearance. These arachnids are carnivorous predators that rely on specialized hunting strategies to capture and consume prey. Their survival depends on their ability to ambush and process small creatures using a specialized web and a unique biological feeding mechanism. This process involves a diet restricted primarily to arthropods, sophisticated entrapment, and external digestion.
The Primary Prey of Black Widows
The diet of the black widow spider consists almost entirely of small arthropods. They are opportunistic hunters, feeding on virtually any suitable creature entangled in their web. Common prey items include flying insects like flies and moths, along with crawling insects such as crickets, grasshoppers, beetles, and cockroaches. Black widows also readily consume other arachnids, including scorpions and smaller spiders. Their venom is highly effective against insects and invertebrates, allowing them to subdue prey several times their own body mass.
How Black Widows Capture Their Meals
Black widow spiders do not actively hunt but construct a permanent tangle web or cobweb. This web is distinctly irregular and chaotic, lacking the symmetrical spiral pattern of an orb weaver’s design. The structure is built near the ground in dark, sheltered areas. A critical component is the use of “gum-footed threads,” which are vertical silk lines anchored to the substrate with sticky glue.
When a crawling insect brushes against a gum-footed thread, the line snaps free from the ground and yanks the prey upward, suspending it in the air. This initial entrapment alerts the spider through vibration. The spider rapidly descends and uses specialized comb-like structures on its hind legs to quickly wrap the struggling victim in thick swathes of silk. Once the prey is immobilized, the black widow delivers a bite, injecting neurotoxic venom to paralyze the prey.
The Unique Digestion Process
The black widow, like all spiders, cannot chew or swallow solid food and must liquefy its meal before consumption. This is accomplished through external digestion, or extracorporeal digestion. After the prey is paralyzed, the spider injects powerful digestive enzymes into the victim’s body. These enzymes quickly break down the insect’s internal tissues, turning the insides into a nutrient-rich liquid. The spider then uses a sucking stomach and pharynx to draw the liquid meal into its body, leaving behind only the hollow exoskeleton.