 This
is a brightly colored and conspicuous species frequently observed in
open,
sunny areas, especially in late summer and early fall. Female
yellow
garden spiders can reach a length of one inch or more. The
carapace
is silvery-white, and the oval, yellow and black abdomen bears of pair
of humps near the base. Males are much smaller, rarely reaching
much
over a quarter of an inch long.
This species occurs in Nova Scotia and southern Ontario, the eastern half of the United States, and south to Guatemala. It also occurs in California and Oregon. It is absent from intervening arid areas. Females build large webs, up to two feet in diameter, in open areas among tall grasses and weeds, often in wet or marshy areas. They are also familiar sites around homes, in flower and vegetable gardens, in old fields, and in similar habitats (Levi 1968; Kaston 1981).
|
The
web consists of dry spokes supporting a spiral thread of adhesive silk.
The hub is separated from the spirals by a free zone. The spiders
rest head down day and night at the hub of the web over a conspicuous
zigzag
band of bright white noncapture silk known as a stabilimentum.
The
stabilimentum apparently affords protection, perhaps by
camouflaging
the spiders, startling predators, or acting as an aposematic warning of
the presence of webs. It seems to be especially effective in
preventing
birds from flying through webs. However, it can also cost spiders
the loss of prey, and hungry spiders, which most need to capture prey,
are less likely to build stabilimenta (Blackledge 1998; Blackledge and
Wenzel 1999). The female usually eats her web each day and
constructs
a new one, often in the same place (Reed et al. 1969). Females
can
handle prey much larger than themselves, including grasshoppers,
katydids,
cicadas, June beetles, moths, wasps, bees, and other insects (Fitch
1963).
In east Texas cotton fields, major prey items are aphids, flies,
grasshoppers,
and ants and bees (Nyffeler et al. 1987).
Spiders
reach maturity in summer. Although males build webs, after they
reach
maturity they wander in search of females, and they can be found in the
females’ webs. Light brown, oval or spherical egg sacs up to an
inch
long are produced in late summer or early fall. Each sac contains
up to a thousand or more eggs. Spiderlings winter over inside the
sacs, and they disperse in the spring. Mortality due to predators
and parasites can be very high (Lockley and Young 1993). In the
spring,
the young spiders build small webs in low vegetation. As they
grow,
they tend to build larger and more conspicuous webs higher in
vegetation.
These
spiders are not particularly dangerous to people, and their bites
result
in nothing more than a sore, itchy swelling that goes away in a few
days.
The medical literature contains at least one report of a bite by A.
aurantia (Gorham and Rheney 1968). Mild pain some
distance
from the site of the bite was suggestive of a neurotoxin.