Jumping spiders belong to the family Salticidae, a group distinguished by their large anterior median eyes and exceptional vision. These small arachnids rely on their eyesight for hunting and navigation, making them highly visual creatures commonly found across diverse habitats worldwide. The reproductive output and subsequent development of their young are governed by a distinct life cycle that begins with elaborate signaling between prospective mates. This process culminates in a female producing a protective silk structure to house her developing offspring.
The Reproductive Cycle
The mating process for jumping spiders is a visually engaging affair, often involving complex courtship rituals performed by the male. Since these spiders possess excellent eyesight, the male must execute species-specific dances, leg-waving, and abdominal vibrations to signal his identity to the female. This display is necessary to ensure the female recognizes him as a mate rather than as potential prey.
After the female accepts the male’s display, the actual transfer of genetic material is indirect, a characteristic shared with other spider groups. The male first spins a small silk “sperm web” and deposits a drop of sperm onto it from his genital opening. He then draws this sperm into specialized, bulbous structures located at the tips of his pedipalps, which are small, leg-like appendages near his mouth.
During copulation, the male uses his pedipalps to insert the sperm into the female’s epigynum, the external genital structure on the underside of her abdomen. Females possess internal storage organs called spermathecae, which allow them to retain and store the sperm for an extended period, sometimes for months. This ability permits the female to fertilize multiple batches of eggs over her lifespan from a single mating event. Once fertilization is complete, the female uses her silk glands to construct a dense, fluffy egg sac where she will lay her eggs.
Offspring Quantity and Clutch Size
The number of babies a female jumping spider has varies significantly, depending on her species, size, and available resources. A single egg sac, typically contains anywhere from a few dozen to over 200 eggs. For instance, species within the common North American genus Phidippus frequently produce clutches containing 50 to 200 eggs. Some studies on different jumping spider species have recorded an average of over 200 eggs within a single sac. This wide numerical range demonstrates the reproductive strategy of producing many small offspring to maximize the chance of survival.
The female’s overall reproductive output is also influenced by her ability to produce multiple clutches throughout her adult life. A female jumping spider can be iteroparous, meaning she produces successive clutches of eggs over her lifetime, often without needing to mate again due to her ability to store sperm.
Many females lay between one and five egg sacs during their breeding season. The total number of offspring produced by a single female over her lifespan can be substantial, with some larger species potentially yielding 500 to 600 spiderlings across all their clutches. Environmental factors such as food availability and temperature play a significant role in determining how many clutches a female can successfully produce and guard.
Maternal Care and Hatchling Development
Once the eggs are laid and sealed within the protective silk sac, the female jumping spider begins a period of dedicated, though limited, maternal care. Her primary role is to guard the egg sac fiercely from predators and parasites. The female will typically remain physically near or directly on the sac for the entire incubation period, which lasts approximately two to six weeks.
During this guarding phase, the mother often ceases feeding and rarely leaves the immediate vicinity of the sac. This commitment ensures the eggs are protected until they hatch. After the spiderlings emerge from the eggs, they remain inside the silken structure, which now functions as a nursery or nest.
The newly hatched young, known as spiderlings or slings, undergo their first molt while still within the safety of the nest. They are extremely small and delicate during this first instar stage. Only after they complete this molt and reach the second instar do the spiderlings begin to disperse from the maternal nest. The mother continues to guard the space and the young for a short period after hatching until the spiderlings are ready to venture out and begin their independent lives.