Spiders are common inhabitants of ecosystems across New Jersey, often sparking curiosity and sometimes apprehension. These arachnids play a beneficial role in controlling insect populations, acting as natural pest managers. While their presence can be startling, most spider species found in the state pose no threat to humans. Understanding New Jersey’s spiders helps appreciate their ecological contributions and differentiate between harmless and potentially cautious species.
Common Spiders in Your Home and Garden
Many harmless spider species are commonly encountered in New Jersey homes and gardens, contributing to natural pest control. Cellar spiders, often called “daddy long-legs,” possess long, thin legs and small bodies, frequently found in damp, dark areas like basements. They spin irregular, tangled webs and vibrate rapidly when disturbed.
Common house spiders are typically brown or gray, constructing messy, irregular webs in corners of rooms, windows, and under furniture. These adaptable spiders are generalist predators, catching a wide range of household insects. Orb weavers, recognized by their intricate, circular webs, are often found outdoors in gardens or near outdoor lights. Their webs efficiently capture flying insects.
Jumping spiders are small, fuzzy, with excellent eyesight and jerky, pouncing movements. They stalk and leap onto prey instead of building webs, commonly seen on walls or foliage. Wolf spiders are robust, hairy ground-dwellers that also hunt without webs, often seen scurrying across lawns, gardens, or homes. Females are sometimes observed carrying their egg sacs or spiderlings on their backs.
Spiders of Medical Concern
While most spiders in New Jersey are harmless, a few species are considered medically significant, though bites are rare. The black widow spider, primarily the northern black widow (Latrodectus variolus), is the main spider of concern in the state. Females are typically glossy black with a red hourglass marking on the underside of their abdomen, though this marking may be broken or appear as two separate red spots.
These spiders prefer dark, undisturbed outdoor areas such as woodpiles, sheds, crawl spaces, and under rocks or debris. A black widow bite can cause localized pain, muscle cramps, nausea, and sweating, with symptoms usually developing within hours. While the venom is potent, severe reactions are uncommon, and fatalities are extremely rare. Individuals suspecting a black widow bite should seek medical evaluation.
The brown recluse spider (Loxosceles reclusa) is not native to New Jersey but can occasionally be transported into the state. This spider is typically light to dark brown with a violin-shaped marking on its cephalothorax, though this marking can be faint. Its bite can cause tissue damage, leading to a slow-healing open sore. If a brown recluse bite is suspected, especially if symptoms include a spreading lesion or fever, medical consultation is advisable.
Typical Habitats for New Jersey Spiders
Spiders in New Jersey occupy a wide range of habitats, both indoors and outdoors, depending on their needs for shelter, prey availability, and environmental conditions. Indoors, many spiders seek dark, secluded, and undisturbed areas. Basements, attics, crawl spaces, and closets provide ideal conditions due to consistent temperatures and reduced human activity. Spiders also frequently inhabit corners of rooms, behind furniture, and in window sills, where they build webs and find small insects.
These indoor environments offer protection from predators and adverse weather, along with a steady supply of prey. Outdoors, habitats are diverse. Gardens, with abundant foliage and insect populations, are common hunting grounds for many species, including orb weavers and wolf spiders. Woodpiles, leaf litter, and areas under rocks or logs offer hiding spots and access to ground-dwelling prey. Spiders also thrive near water sources like ponds or streams, which attract a variety of insects. Trees and shrubs provide elevated positions for web-building spiders, allowing them to capture flying insects, while sheds and outbuildings offer sheltered spaces similar to indoor environments.
Key Features for Spider Identification
Identifying spiders involves observing a combination of distinct physical characteristics. One primary feature is the arrangement of their eyes, as the number and pattern vary between spider families. For instance, wolf spiders typically have eight eyes arranged in three rows, while jumping spiders also have eight eyes but with a prominent pair of large anterior eyes.
The overall body shape, including the relative sizes of the cephalothorax (head and thorax combined) and abdomen, provides additional clues. Some spiders have relatively small abdomens, while others, like many orb weavers, possess large, rounded abdomens. The presence or absence of hair or spines on the body and legs can also be a distinguishing factor, as can the length and thickness of their legs.
Observing the color patterns and markings on the body, such as the hourglass shape on a black widow or the violin pattern on a brown recluse, is also crucial. If a web is present, its structure—whether it’s an irregular tangle, a flat sheet, or a classic orb—can be a strong indicator of the spider’s identity. Taking clear photographs from multiple angles can be very helpful for later comparison with reliable identification guides.