Sunday, May 13, 2012

Into the world of Borneo's jumping spiders

A RECENT talk at the Sarawak Biodiversity Centre opened my eyes to the world of jumping spiders.

Spiders are not insects, but air-breathing arthropods, which include animals such as crabs.

There are over 40,000 species of spiders in the diverse order Araneae. Only one species of spider is not carnivorous. While most eat insects and other spiders, some of the larger spiders also prey on birds and other larger prey.

Most spiders spin webs to trap prey, however, jumping spiders, which are members of the Salticidae family, are the tigers of the spider world.

They are visual hunters with eight eyes and can see in a complete circle. They stalk their prey and then with a powerful jump spring the fatal surprise.

It is surprising to note that the jump is powered by a burst of high blood pressure, not by leg muscles (spiders have none).

The prey is then dragged back to the starting point via the silk rope, which the spider is attached to.

These spiders, which range in size from two millimetres to seven millimetres, have stout bodies with two segments — the thorax and abdomen.

They are generally rectangular, but can be other shapes including linear, round, triangular and square. Like other arthropods, they have eight legs. They can be brightly coloured — red, yellow, green violet, blue.

They are also mimics with some species looking like ants so that they can move among their prey undetected. Silk is produced in special glands on the abdomen.

The spider-produced silk is also used to create a sticky silken nest or home for the spider.

Females will also lay their eggs in silk nests. Spider courting can be dangerous and one of the aims of the male spiders is not to get eaten by the female it is interested in.

About 100 species of jumping spiders have been identified in Borneo, but the researchers who presented, Dr Wayne Maddison and Edyta Piassak, identified 175 and believe there to be more species.

Continue reading (Incl. Pic) at: Into the world of Borneo's jumping spiders