(IPPM) in Vegetables - Vegetableipmasia.org

Resource Manual on IPPM in Vegetable
World Education Philippines, Inc.
Growth and Longevity
Spiders grow by periodically shedding their semi-rigid external 'skin' or cuticle of semi-rigid
chitin and replacing it with a new larger skin they have grown underneath the old one. This
process is called ecdysis or moulting. This process includes replacement of every hair on the
body and internal cuticular structures such as the fore and hind gut linings and female
genitalia. Once they are mature most araneomorph spiders stop moulting. However, female
mygalomorph spiders moult throughout life, although at longer intervals as they get older.
This allows some species, particularly tarantulas (Theraphosidae), to grow very large.
During the moulting process, which may take many hours, the spider is in great danger
from predators, being soft-bodied and unable to move until its new cuticle has hardened.
For this reason moulting is often done at night when the spiders hung safely in mid-air
from a silk line; or sealed within a silk retreat or moulting chamber, e.g., in a curled leaf,
a burrow, or under bark.
Egg Sac to Adult
Spider eggs develop and hatch within the egg sac; the larval spiders undergo at least one
further moult before emerging from the sac. The number of growth moults varies between
species, as well as with size and nutritional state. Poorly fed spiders will moult fewer times
and become smaller adults. Most spiders undergo 5-10 moults to reach adulthood. Males
often have fewer and faster moults. Extreme examples of this are given by the Magnificent
spider (Ordgarius magnificus) and the Bird Dung spider (Calaenia kinbergi), both large,
specialised moth-catching relatives of the orb weavers. The males moult only within the egg
sac, emerging as tiny, fully mature males along with their similarly sized and very immature
sisters, which will take many weeks and moults to become large adult females.
A spider's appearance can change considerably during growth from spiderling to adult, as
indicated by these stages in Redback spider development. Adult males and females also may
look quite different, especially in respect of size and colour. Spiders with good eyesight like
jumping spiders often have colourful or strikingly marked males which differ considerably
from their less colorful females.
What Spiders Eat
Spiders eat invertebrates (insects and other small animals without backbones) and larger
spiders may eat small vertebrates such as frogs and some birds. Spiders in Australia have
developed many different ways of finding and catching food. Some hunt for prey at night
while others hunt during the day. Some prowl around and pounce on their prey while others
wait for prey to come to them. Most spiders inject their prey with venom from their fangs.
This venom helps dissolve the tissues of the prey's body so the spider can suck it up as a
liquid.
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