Trade-offs in antiherbivore defenses in Piper cenocladum: Ant mutualists versus plant secondary metabolites

Citation
La. Dyer et al., Trade-offs in antiherbivore defenses in Piper cenocladum: Ant mutualists versus plant secondary metabolites, J CHEM ECOL, 27(3), 2001, pp. 581-592
Citations number
41
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology
Journal title
JOURNAL OF CHEMICAL ECOLOGY
ISSN journal
0098-0331 → ACNP
Volume
27
Issue
3
Year of publication
2001
Pages
581 - 592
Database
ISI
SICI code
0098-0331(200103)27:3<581:TIADIP>2.0.ZU;2-U
Abstract
Ant-plant mutualisms may provide indirect evidence for costs of antiherbivo re defenses when plants demonstrate trade-offs between allocating resources and energy into ant attractants versus chemical defenses. We tested the hy pothesis that ecological trade-offs in defenses are present in Piper cenocl adum. This plant possesses two distinct defenses: food bodies that attract predatory ants that destory herbivore eggs and amides that deter herbivores . Previous studies have demonstrated that the food bodies in P. cenocladum are an effective defense because the ants deter herbivory by specialist her bivores. Amides in other Piper species have been shown to have toxic qualit ies, but we tested the additional hypothesis that these amides have an actu al defensive function in P. cenocladum. To rest for ecological trade-offs b etween the two putative defenses, fragments of P. cenocladum were examined for the presence of amides both when the plant was producing food bodies an d when it was not producing food bodies. Plants with active ant colonies ha d redundant defenses, producing food bodies and high levels of amides at th e same time, but we detected a trade-off in that they had significantly low er levels of amides than did plants with no ants. To test for the defensive value of P. cenocladum amides, we used an ant bioassay and we examined her bivory results from previous experiments with plants that had variable leve ls of amides. These tests demonstrated that amides are deterrent to omnivor ous ants, leaf cutting ants, and orthopterans. In contrast, the resident Ph eidole bicornis ants are effective at deterring herbivory by specialist her bivores that oviposit eggs an the plant but not at deterring herbivory by n onresident omnivores. We concluded that although both amides and food body production appear to be costly, redundancy in defenses is necessary to avoi d damage by a complex suit of herbivores.