October 31, 2003

Art Gallery

View past galleries

Scientists have now measured the genome sizes of some 115 spider species, from ghost spiders to cobweb weavers to jumping spiders. Despite their abundance and diversity—there are more than 37,000 known species of spiders worldwide—little has been known about their genomic make-up.

Habronattus species have some of the largest genomes among spiders. Also called jumping spiders, their big eyes and engaging behavior make them the teddy bears of the spider world. Image courtesy Marshal C. Hedin.

So far, it appears that jumping spiders have the largest genomes. With their big eyes and engaging behavior, they are considered the teddy bears of the spider world. Jumping spiders prey on flies. They are also characterized by a "jerky" way of moving around. In fact, they look like they are hopping every time they move.

Some of the smallest spider genomes are found in the orbweaver family. Orbweavers, also called stretch spiders, build their webs at an angle instead of straight up and down.

Spiders such as the black and yellow argiope (Argiope aurantia) construct elaborate webs and often add stabilimenta, or heavy zig-zagging portions, in their webs. The large spider is a female, and the smaller one is a male. Image courtesy Troy Bartlett.

Comparative studies of spider genomes could provide clues why some spiders build webs and others don't. Genome studies may also help answer questions about spider longevity—why some spider species may survive for 20 years and others live only one year.

Female redback spiders (Latrodectus hasselti) may live for two to three years, whereas males only live for about six or seven months. Image courtesy Ed Nieuwenhuys.

The sizes of all the spider genomes are stored in an online database. The Animal Genome Size Database includes organisms from insects to spiders to earthworms and includes the genome sizes of more than 3,000 animals.

The database can be accessed here.

—Birgit Reinert

. . .

Gregory, T.R. & Shorthouse, D.P. Genome sizes of spiders. J Hered 94, 285-290 (July/August 2003).

Back to GNN Home Page

Genome News Network is an editorially independent online publication of the J. Craig Venter Institute. © 2000 - 2004 J. Craig Venter Institute. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.