Science and Technology News

Friday, April 20, 2012

Jumping Spider Mimics

A jumping spider (Hypaeus benignus) from the La Selva Biological Station in Costa Rica. H. benignus is about 7 millimeters long.

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As part of her dissertation research, supported by a National Science Foundation graduate research fellowship, Lisa Taylor of Arizona State University's (ASU) School of Life Sciences studied mimicry in the jumping spider family Salticidae. Salticidae are the largest family of jumping spiders in the world.

In biology, mimicry is the similarity of one species to another. The mimicry may offer protection from predators for one or both of the species involved, and may help the mimic acquire food more easily. The mimicking species may be similar to the mimicked in appearance, behavior, sound, scent and location.

There are four types of mimicry used by spiders:

• Batesian--When the mimic takes on characteristics of an organism that is harmful (may sting or bite) and bad tasting, like an ant or wasp, thus helping the spider avoid becoming a meal (Taylor believes that most of the jumping spiders she studied were Batesian mimics).

•Wasmannian mimicry--When the mimic resembles an organism in order to come and go in the organism's territory undisturbed, and may or may not be harmful to the organism. For example, the ability to mimic ants (the technical term for this is myrmecomorphy), particularly those with nasty stings and bites, gives jumping spiders protection from the predators that feed on them such as birds, wasps and lizards. Mimicking ants also gives spiders access to areas where they can hunt and hide that typically would be off limits. Some spiders have the ability to smell like ants--ants use chemical signals to communicate. By mimicking the scent of ants, the spiders can roam freely in and out of ant nests, where they may live or feed on ant larva.

•Peckhamian (or aggressive) mimicry--When an aggressive mimic imitates its prey so it may feed on it more easily. For example, the bolas spider hangs a glob of sticky glue in the air that contains a chemical that mimics the pheromone of a female moth. When male moths fly near to check out the potential "mate," they get stuck to the blob and become a meal for the spider.

•Mullerian mimicry--When the mimic has distinctive, brightly striped patterns that resemble those of a toxic bee or wasp (although no toxic jumping spiders have been identified so far). For example, spiders that mimic the large, fuzzy and brightly colored velvet ant (which is actually a wingless wasp) are protected from potential predators because they associate bright-colored creatures with a painful sting and stay away.

Currently, Taylor is studying the courtship rituals of jumping spiders. In particular, she is interested in how animals use color to communicate. In her dissertation work at ASU, she is working with a group of colorfully ornamented jumping spiders (like the ones pictured here) in the genus Habronattus. She's trying to understand how they use color to advertise themselves to potential mates and competitors, as well as to deceive and avoid potential predators. (Date of Image: 2005-2010)

Credit: Lisa Taylor, Arizona State University

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