Wolf spiders (family Lycosidae) are known for their unique and extensive maternal care, unlike many other spider species. The female wolf spider carries her offspring through two distinct phases of early development. This commitment involves first carrying a silk-encased egg sac and then transporting the newly hatched spiderlings on her back. This behavior significantly increases the survival rate of her young in the wild.
The Initial Phase: Carrying the Egg Sac
The maternal journey begins immediately after the female lays her eggs, encasing them in a spherical, silken egg sac. She attaches this package directly to her spinnerets, the silk-extruding organs located at the rear of her abdomen. This attachment allows her to drag the sac behind her everywhere she goes, which is a remarkable feat for an active hunter.
By carrying the sac, the mother actively protects the developing embryos from predators and parasites. She often raises the sac toward the sun to help regulate the temperature of the eggs inside, demonstrating thermoregulation. This phase of carrying the unhatched eggs lasts for several weeks, depending on the species and environmental conditions.
Duration of Carrying the Spiderlings
The second phase begins when the eggs hatch, often assisted by the mother tearing open the egg sac to release the spiderlings. Once free, the tiny spiderlings immediately swarm onto the mother’s abdomen and back, forming a dense, living layer. They cling tightly to specialized, knob-shaped hairs on her body, which provide a secure anchor for the mass of young.
During this period, the mother continues to hunt and move, providing her offspring with protection and transportation. The spiderlings do not feed while riding, instead relying on the remaining yolk reserves from their eggs. This “hitchhiking” phase typically lasts for a couple of weeks, though the duration depends on the species and local climate.
The end of this carrying period is triggered when the spiderlings complete their first molt (instar) while still on the mother’s back. This molt signifies their readiness to begin life outside the protective environment of their mother’s body. Once complete, the young spiders are prepared to dismount and search for their own resources.
Independence and Dispersal
Once the spiderlings are ready, they voluntarily dismount from their mother’s back and begin their solitary lives. The departure is a form of dispersal, with the young moving away quickly to avoid competition. A common method of dispersal is a behavior known as “ballooning”.
In ballooning, a spiderling climbs to a high point, releases a strand of silk into the wind, and is carried away by air currents. This process can carry them significant distances, helping to spread the population and reduce the chances of cannibalism. The mother, having invested heavily in her young, often dies shortly after the spiderlings leave.