bivittatus is a spider in the Salticidae family commonly known as
the gray wall jumper. It is a pantropical species and is usually
found on the walls of buildings or on tree trunks where it stalks
Menemerus bivittatus is cosmopolitan in distribution being common in
most tropical regions. In North America, the species is found in
Florida, Texas and California and south as far as Paraguay. It is
often seen on the outside of man-made structures.
Gray wall jumpers are dorso-ventrally flattened and are covered with
short dense, grayish-white hairs. There are tufts of dark brown
bristles near the large, forward-facing eyes. The spiders are about
nine millimetres long, the male being slightly smaller than the
female. The male has a blackish longitudinal dorsal stripe with a
brownish-white stripe on either side of the abdomen. The carapace
and chelicerae are also black and white and the legs have transverse
bandings of the same colours. The female is generally paler and more
brown, with a larger carapace and abdomen. Her carapace is edged
with two black bands and a thin white stripe and her abdomen is
edged with broad black stripes on each side which unite at the
posterior end. Her legs are banded but are paler than those of the
male. Immature spiders resemble the female.
The female gray wall jumper builds an eggsac in a crack or other
concealed position in which she lays 25 to 40 eggs in a purse-like
silken case. She guards the eggs until they hatch in about three
weeks time after which the young spiders disperse.
Both young and old spiders feed mainly on small flies which alight
on walls. They do not build a web but instead, stalk their prey
before launching an attack by leaping on the victim. They have high
visual acuity and their large eyes are able to focus on objects and
detect different colours. They use their highly coordinated jumping
ability to capture their prey and to move from one place to another.
They are capable of capturing insects such as crane flies that are
at least twice their own size.
Male spiders of this species possess a stridulatory apparatus which
consists of several long bristles on the palpal femur and a series
of horizontal ridges on the outer side of the chelicerae. Sound is
generated when the spider rubs these ridges up and down against the
palpal teeth. This is believed to be part of a courtship display by
In India this common spider is found on the outer walls of buildings
and on tree trunks. It moves actively about in search of small
insect prey, often vibrating its hairy palps as it walks. In the
Gambia, spiders of this species have been observed loitering near
and observing the entrances to nests of stingless bees. It is
difficult for the spider to catch the bees as they fly out of the
entrance but the bees are more vulnerable when returning to the nest.