Jumping spiders (family Salticidae) are known for their distinctive appearance and behavior. Their large, forward-facing eyes grant them exceptional vision, which is vital for their successful hunting strategy. Unlike many spiders that rely on webs, jumping spiders actively stalk and pounce on prey, requiring precise depth perception. This excellent eyesight also plays a role in their complex reproductive cycles.
Frequency of Egg Laying
A female jumping spider typically mates once, storing the male’s sperm in specialized internal structures called spermathecae. This allows her to utilize the sperm throughout her entire reproductive life. Following successful mating, the female becomes gravid and generally lays her first clutch of eggs within one day to two weeks.
A female’s reproductive output is measured in “clutches,” which refers to a single batch of eggs contained within an egg sac. Over her lifespan, which often lasts a single season, a female produces multiple clutches sequentially. The average number of egg sacs laid is usually between three and six, though this varies depending on her species, health, and environmental conditions.
The frequency of egg-laying is tied to the mother’s recovery and the development of the previous clutch. A female typically does not lay a new sac until the spiderlings from the last one have hatched or dispersed. Factors like food availability and a stable climate influence her ability to recover and allocate resources for subsequent cycles. If conditions are poor, the time between clutches lengthens, and the total number of clutches may decrease.
Construction and Contents of the Egg Sac
When ready to lay eggs, the female constructs a specialized protective structure known as the egg sac. This sac is woven from thick, dense silk, providing a protective and insulated environment for the developing young. She usually chooses a secluded location for deposition, such as a crevice, beneath bark, or within a larger silk retreat.
The physical characteristics of the sac vary by species, but they are generally round or dome-shaped and often described as fluffy. Inside the silk casing, the eggs are a creamy yellow color. The number of eggs in a single sac varies significantly, ranging from approximately 50 to over 200 eggs. Larger species tend to produce sacs with a higher quantity of eggs.
Over time, the sac may change color from pale yellow to a darker shade. This color change indicates that the spiderlings have developed and undergone their first molt inside the protective structure, signaling the nearing completion of the incubation period.
Maternal Protection and Hatching
Female jumping spiders exhibit maternal care, dedicating themselves to protecting the egg sac after it is laid. The mother remains in constant proximity to the clutch, guarding it diligently until the eggs hatch. During this time, she may refrain from eating or drinking for extended periods, only occasionally venturing out for sustenance.
The incubation period, from laying to hatching, typically lasts between one and four weeks. After hatching, the tiny spiderlings remain inside the protective sac for a short duration, undergoing their first molt. The total time until the spiderlings fully emerge and disperse is usually between 40 and 50 days. Once they emerge, they are in their second instar and may stay near the female briefly before dispersing to begin independent lives.