Phidippus putnami

Physical description and identification

Phidippus putnami is a compact, heavily built jumping spider that looks front-heavy from any angle: a high, squared carapace carrying two enormous forward-facing eyes, thick front legs, and a body clothed in dense coloured scales rather than plain hairs. It is a medium-sized member of Phidippus and belongs to a group of rust-coloured relatives that are genuinely difficult to tell apart in photographs.

Adults

• Size: published figures of 8–15 mm (0.3–0.6 in) cover both sexes and the largest gravid females; a typical adult female is about 9–12 mm and a male 7–10 mm, with the legs adding roughly as much again to the apparent size.
• Color: warm brown to rusty orange-brown, from a coat of coloured scales over a darker cuticle. The abdomen usually carries a pale band across the front edge, a darker central field and one or two pairs of small pale spots or short chevrons behind it. The legs are dark and banded, and in adult males the first pair is fringed with conspicuous white hairs that the spider waves during courtship. Worn individuals late in the season can look almost uniformly drab.
• Eyes: eight eyes in four pairs. The two anterior median eyes are very large and point straight forward; smaller lateral eyes sit beside and behind them, covering close to a full circle. Only the big front pair resolves real detail — the side eyes are motion detectors that tell the spider which way to turn. Our guide to spider eyes sets out the arrangement, which separates any salticid at a glance from a wolf spider or a crab spider.
• Distinctive features: as in all Phidippus, the chelicerae are iridescent and flash metallic green, blue or violet in sunlight. That shimmer, and not any genuine colour morph, is the origin of the claim that the species comes in a blue form. Confident species-level identification here rests on the male pedipalp or the female epigyne rather than on colour.

Eggs and egg sac

The female builds a thick silk retreat — typically between two leaves drawn together, inside a curled leaf, or in a bark crevice — and lays a batch of small pale eggs in a sac inside it, then seals herself in and guards them, feeding little. Incubation runs roughly one to four weeks depending on temperature.

Spiderlings

The hatchlings remain in the maternal retreat through their first moult, living on yolk, then disperse into the surrounding vegetation and hunt independently at a few millimetres long. Juveniles look like duller, paler adults and grow through a series of moults — see how spiders moult and the wider spider life cycle. Most individuals pass the winter as well-grown juveniles and mature the following spring.

Hunting and the use of silk

This spider builds no capture web, and neither does any other jumping spider. It is a stalking hunter: the wide-field side eyes pick up movement, the spider pivots to bring the high-resolution front eyes onto the target, creeps within a body length or two, and jumps. Silk is still used constantly — a dragline anchored before every leap, which both rescues a failed jump and lets the spider adjust its body angle in mid-air, and a retreat used for moulting, resting and holding the egg sac. Binding two leaves together to make that shelter is real behaviour, but the resulting tent is a bedroom, not a snare, and nothing like the sticky spider web of an orb weaver.

Where Phidippus putnami lives

Phidippus putnami is an eastern and central North American species. Records run from southern Canada and the Great Lakes south through the Appalachians and the Atlantic states to Georgia and Florida, and west across the Mississippi basin into the eastern plains and Texas. Older accounts that simply give the distribution as "the United States" understate the northern half of the range, which reaches well into Canada.

It is a spider of vegetation rather than of the ground or of bare bark. Look for it on shrubs, saplings, bramble, goldenrod and other tall herbaceous growth at the edges of woods, in old fields and along hedgerows, and on fences and sunlit exterior walls. It is not a resident house spider: individuals that wander indoors will not establish a population inside.

Is Phidippus putnami venomous?

Yes, in the sense that nearly every spider is venomous — it injects venom to subdue the insects it catches. It is not dangerous to people or pets. Jumping spider venom is tuned to small arthropods and contains neither the tissue-destroying enzymes of the recluse spiders nor the vertebrate-active neurotoxins of the widow spiders. No member of the family Salticidae is considered medically significant anywhere in the world; the one realistic exception is an individual allergy to arthropod proteins, which is a property of the person rather than of the venom.

Can Phidippus putnami bite?

It can, but the event is rare and always defensive. A spider of this size has fangs long enough to break human skin if it is squeezed, pressed inside clothing or held tightly. Approached normally it swivels to look, retreats a step, then runs or drops away on its dragline. Curiosity, not aggression, is why one will sometimes turn and watch a finger from a few centimetres away.

A bite feels like a pinprick and leaves a small red mark with brief soreness or itching that usually fades within a few hours. Wash with soap and water, apply a cold pack and leave it alone; no home remedy is needed. Seek medical advice only if redness spreads, swelling is out of proportion, or there are signs of a general allergic reaction such as hives or difficulty breathing.

Ecological importance and behavior of Phidippus putnami

This is a diurnal visual predator that patrols foliage in sunshine and takes whatever it can overpower: flies, small moths, leafhoppers, plant bugs, aphids, beetles, caterpillars and other spiders. Because it hunts on the plant surface rather than waiting in a snare, it reaches insects that would never blunder into a web, which makes a hedgerow population a useful part of pest regulation.

Natural predators: the short list of "parasitoid wasps and nematodes" that circulates for this species is far too narrow, and nematodes are internal parasites rather than predators. In practice the spider is eaten by insectivorous birds, lizards and amphibians, hunted by mud-dauber and spider-hunting wasps that paralyse spiders to stock their nests, and taken by larger spiders including other Phidippus. Parasitoid wasps and flies attack the egg sacs.

How the jump works: spiders have no extensor muscles at the crucial leg joints. The spider raises the pressure of the fluid inside its body and forces the hind legs straight, so the leap is hydraulic as much as muscular. The dragline laid before take-off works as a brake and a tether — which is why a jumping spider knocked off a leaf dangles rather than falls.

Courtship and season: adults are most often seen from late spring into early autumn. The male approaches with an elaborate visual display, raising and waving the white-fringed front legs and drumming his abdomen — a performance that identifies his species and stops the larger female treating him as prey. Juveniles pass the cold months sealed in silk retreats under bark and in litter; see where spiders go in winter.

Relationship with humans: harmless, beneficial and in need of no control. If one wanders indoors, carry it out on a sheet of paper.

Similar spiders and how to tell them apart

Quick facts

Did you know?

• The species was described in 1883 by George Williams Peckham and Elizabeth Maria Gifford Peckham, whose work on salticid courtship founded the study of spider behaviour. The name honours Joseph Duncan Putnam, an Iowa naturalist of the same generation.
• Jumping spiders swivel their retinas, not their eyes. Muscles inside the head drag the tube-shaped retina of each principal eye from side to side, so the spider can scan an object without moving its body.
• Salticidae is the largest of all spider families, with well over 6,000 described species; browse the rest of it on our jumping spiders page, from the zebra jumper to the regal jumping spider.

In summary, Phidippus putnami is a sharp-eyed, entirely harmless hunter of eastern woodland edges — a spider that builds no trap, watches you as carefully as you watch it, and quietly clears insects from the vegetation around it.