Redback Spider

The redback spider, Latrodectus hasseltii, is a member of the widow spider genus Latrodectus and is found throughout Australia, having also become established in parts of Southeast Asia and New Zealand through incidental transport. It is closely related to the black widow spiders of the Americas and shares the family's characteristic globular, glossy black body, though the redback is distinguished by the bold red or orange stripe running down the top of the female's abdomen.

Females are considerably larger and more conspicuous than the tiny, brownish males, which are rarely noticed and are sometimes found sharing the female's web. Redback spiders build an irregular, tangled cobweb close to the ground, typically in dry, undisturbed locations near or within human structures, which has made them a familiar spider to encounter around homes, sheds, and outdoor furniture across Australia.

As with other widow spiders, redbacks are opportunistic predators that play a role in controlling insect and small invertebrate populations in the sheltered spaces they inhabit.

• Glossy black, globular abdomen with a distinctive red or orange longitudinal stripe on females
• An hourglass-shaped red or orange marking is often visible on the underside of the abdomen as well
• Males are much smaller, brownish, and lack the bold coloring of females, making them easily overlooked
• Long, thin legs relative to the rounded body, typical of cobweb spiders
• Builds an irregular, tangled web low to the ground in sheltered, dry locations
• Lookalikes include other Latrodectus species such as the black widow, which lacks the continuous red dorsal stripe seen in redbacks

Redback spiders favor dry, sheltered microhabitats close to the ground, including garden sheds, mailboxes, outdoor furniture, woodpiles, and debris. They are found throughout Australia in both urban and rural settings and have also become established in parts of Japan, Southeast Asia, and New Zealand. Activity is generally year-round in warmer regions, with populations often increasing during the warmer months.

Redback spiders construct a messy, irregular cobweb close to the ground, with sticky trap lines running down to the surface to snare crawling insects as well as flying ones that blunder into the upper web. The female typically remains within a small silk retreat within the web, emerging to subdue and wrap prey caught on the sticky lines. They are not aggressive and generally remain within or near their web rather than roaming, retreating deeper into the web structure when disturbed. As predators of insects and other small invertebrates, they contribute to natural pest regulation in the sheltered spaces where their webs are built.

After mating, during which the much smaller male faces considerable risk from the female, females produce multiple round, silk egg sacs containing large numbers of eggs, often across several batches over their lifetime. Spiderlings hatch and disperse from the maternal web to establish their own webs nearby. They molt numerous times as they grow, with development speed depending on temperature and food availability, and females can live a year or more, continuing to reproduce over multiple breeding events, while males have a considerably shorter lifespan.