Wolf spiders (family Lycosidae) are common, ground-dwelling arachnids found across most of the globe. They are famous for their unique method of parental care, which is an exception to the typical solitary behavior of most spiders. The female wolf spider definitively carries her young upon her back for a period after they hatch. This behavior represents a high level of maternal investment.
The Unique Behavior of Carrying Spiderlings
The act of carrying spiderlings is a demanding display of maternal protection. After the young emerge, sometimes numbering well over a hundred, they instinctively clamber onto the mother’s back, covering her abdomen and the rear of her cephalothorax. This dense cluster of tiny bodies can completely obscure the mother’s coloring.
The spiderlings cling tightly, often using specialized hairs on the mother’s cuticle to maintain their hold. Despite carrying this large brood, the mother remains an active hunter, capable of moving quickly and capturing prey to sustain herself and defend her young.
From Egg Sac to Hatching
The carrying of live young is the second phase of the wolf spider’s intensive maternal care, preceded by the transportation of the egg sac. The mother spins a tough, spherical silken ball, which she attaches firmly to her spinnerets. This attachment allows her to drag the sac everywhere she goes, ensuring it is never left unguarded.
The mobile egg sac is often pale white or green. The female must hold her abdomen in a raised position to prevent the ball from dragging on the ground. When the eggs are ready to hatch, the mother tears open the sac with her chelicerae. The number of eggs can vary widely, sometimes exceeding one thousand in larger species.
When and How Spiderlings Disperse
The period during which the spiderlings ride on their mother’s back typically lasts for a few days up to two weeks, depending on the species and environmental conditions. During this time, the young spiders do not feed, relying instead on the remaining yolk reserves from their embryonic stage. Protection is necessary until the spiderlings have undergone their first molt and are sufficiently developed to survive independently.
Once they reach maturity, the spiderlings begin to disperse from the mother’s back. The final stage frequently involves a behavior known as ballooning. Ballooning allows the tiny spiders to climb to a high point, release a silk thread, and be carried away by wind currents, minimizing local competition and avoiding potential cannibalism.
Identifying Wolf Spiders
Wolf spiders are robust, agile hunters with noticeably hairy bodies, often appearing in shades of brown, gray, or black with various markings. They are ground-dwellers and do not construct webs to capture prey, relying instead on speed and excellent eyesight to stalk and pounce. Their rapid movement across lawns and gardens is a key behavioral identifier.
The most reliable physical trait for identification is their distinctive eye arrangement, featuring eight eyes set in three rows. The bottom row consists of four small eyes, the middle row contains two very large, prominent eyes, and the top row has two medium-sized eyes on the cephalothorax.