Ascorbic Acid, Alcohol, and Environmental Chemicals a

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73093/1/j.1749-6632.1987.tb23775.x.pd

The Benefits of Mutualism: A Conceptual Framework

There are three general mechanisms by which phenotypic benefits are transferred between unrelated organisms. First, one organism may purloin benefits from another by preying on or parasitizing the other organism. Second, one organism may enjoy benefits that are incidental to or a by-product of the self-serving traits of another organism. Third, an organism may invest in another organism if that investment produces return benefits which outweigh the cost of the investment. Interactions in which both parties gain a net benefit are mutualistic. The three mechanisms by which benefits are transferred between organisms can be combined in pairs to produce six possible kinds of original or ‘basal’ mutualisms that can arise from an amutualistic state. A review of the literature suggests that most or all interspecific mutualism have origins in three of the six possible kinds of basal mutualism. Each of these three basal mutualisms have byproduct benefits flowing in at least one direction. The transfer of by-product benefits and investment are common to both intra- and interspecific mutualisms, so that some interspecific mutualisms have intraspecific analogs. A basal mutualism may evolve to the point where each party invests in the other, sometimes obscuring the nature of the original interaction along the way. Two prominent models for the evolution of mutualism do not include by-product benefits: Roughgarden's model for the evolution of the damsel-fish anemone mutualism and the ‘Tit-for-Tat’ model of reciprocity. Using the conceptual framework presented here, including in particular by-product benefits, I have shown how it is possible to construct more parsimonious alternatives to both models.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72439/1/j.1469-185X.1995.tb01196.x.pd

Interaction between bottlenose dolphin (Tursiops truncatus) and trammel nets in the Archipelago de La Maddalena, Italy

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SIGNAUX D'ECHOLOCATION ET COMMUNICATION CHEZ UN DAUPHIN D'EAU DOUCE : APPROCHE FONCTIONNELLE

L'analyse des signaux acoustiques d'un dauphin amazonien, Sotalia, montre que les clics d'écholocation sont, chez cette espèce, associés à des sifflements, attribués à une fonction de communication intra spécifique. Le mode d'association des deux types de signaux représenté par l'évolution sans discontinuité d'un clic en sifflement monochromatique, et réciproquement, peut être expliqué à partir d'une unicité fonctionnelle du système phonateur.Sotalia emits the two separate sequences of signals, common to all Odontocetes species : echolocation clicks and communication whistles. We found frequent and continous shifts from clicks to whistling and reciprocally. It seems to indicate that this specie is able, either to use a single source to produce both type of sounds, or to synchronise the use of two emitting organs