Black widow spiders (Latrodectus) do not follow a fixed feeding schedule; their consumption frequency is highly variable. Their feeding habits typically involve long stretches of fasting punctuated by periods of intense consumption. How often they eat depends drastically on the spider’s sex, developmental stage, surrounding temperature, and the abundance of prey.
The Black Widow Diet and Prey Capture
Black widow spiders are opportunistic predators that primarily feed on crawling insects and other arthropods that stumble into their webs. Their usual menu includes flies, mosquitoes, grasshoppers, beetles, and ants. They can also subdue larger, nutrient-dense prey like cockroaches and even small vertebrates such as lizards, which become entangled in their strong silk. They are sit-and-wait hunters, relying on their irregular, three-dimensional tangle webs. When prey is trapped, the spider senses the vibrations and rapidly descends to inject venom that paralyzes the victim.
The venom contains neurotoxins and digestive enzymes, which begin to break down the prey’s internal tissues while it is still wrapped in silk. The black widow then consumes the pre-digested liquid, leaving behind an empty husk, which allows them to process large meals efficiently.
Factors Influencing Feeding Frequency
The most significant influence on feeding frequency is sex and reproductive status, as females have vastly different energy requirements than males. Adult females are much larger and require considerable energy, especially for producing multiple egg sacs. During the pre-oviposition period, females can become voracious eaters, sometimes feeding daily or every few days if prey is available.
Male black widows are much smaller and spend their adult lives primarily searching for mates, leading them to eat much less often. A well-fed female is less likely to engage in sexual cannibalism, which provides a survival advantage for the male during mating.
The spider’s life stage is also a factor, with juveniles needing to eat more frequently than adults for rapid growth and molting. Temperature is a primary factor, as black widows are ectotherms whose metabolism is governed by their environment. In warmer conditions, their metabolic rate increases, leading to a greater need for food. Conversely, cold temperatures slow metabolism dramatically, reducing the urgency to feed and allowing them to subsist on stored reserves.
Survival Without Food
Black widow spiders possess the ability to survive extended periods without a meal. This is due to their low metabolic rate, which minimizes energy consumption when food is scarce. They have been known to survive for several weeks, and some reports cite survival for three or four months, or even nearly a year under cool, quiet conditions. Access to water or ambient humidity remains important for preventing dehydration during prolonged fasting.