Animal and plant communication at the ESA Annu...('s no evidence that the coloration in pi...)
's no evidence that the coloration in pitcher plants is of any adaptive value for capturing prey," he says. "We don't need to assume that it has an adaptive value, or that it has anything to do with prey."
Specialists are better at avoiding predators
Insect herbivore species often specialize on the host plants that they eat, evolving adaptations to use a plant's unique set of resources. However, specialization doesn't come without costs.
"A lot of evolutionary ecologists have pondered the advantages of being a specialist, and there are presumably tradeoffs," says Michael Singer of Wesleyan University. "Specialists have a smaller resource base, but they might be better adapted to their niche."
Singer and his colleagues wondered if there could be other advantages to specialization than better utilization of host plants as food. Specialists might also be more adept than generalists, he postulated, at using their host plants for defense or refuge from predation, specifically by birds.
The team tested this idea by excluding birds from experimental plots in a temperate forest in Connecticut and surveying the density of generalist and specialist caterpillar species inside and outside the exclosures. In the exclosures, his team observed a surge in generalist density compared to natural areas. The number of specialists, however, only increased slightly. These results suggest that the bird predators were preferentially targeting generalists.
The difference is likely due to the specialists' ability to take better advantage of their host plants, says Singer. Many specialists use chemicals from their host plant's tissue to make themselves toxic. Others, like Singer's specialist caterpillars, might be more adept at camouflaging themselves by finding the best places to hide or to blend in.
Singer's experiment is the first to quantify bird predation on specialist and generalist herbivores, and he hopes
'/>"/>
| Contact: Christine Buckley christine@esa.org 202-833-8773 Ecological Society of America Source:Eurekalert |
Related biology news :
1. Earliest animals lived in a lake environment, research shows
2. Warmer environment means shorter lives for cold-blooded animals
3. Research network wins approximately £5.7 million to target human and animal diseases in Africa
4. Researchers shed light on trading behavior in animals -- and humans
5. Recruitment of reproductive features into other cell types may underlie extended lifespan in animals
6. FAO/IAEA Symposium to address animal production and health
7. Some vocal-mimicking animals, particularly parrots, can move to a musical beat
8. Countries unite to reduce animal use in product toxicity testing worldwide
9. Genome projects launched for three extreme-environment animals
10. Animals that seem identical may be completely different species
11. The life histories of the earliest land animals
| Copyright © 2003-2009 Bio-Medicine. All rights reserved. ABOUT | CONTACT US | DISCLAIMER | PRIVACY POLICY | TERMS AND CONDITIONS |  |