Monday, October 19, 2009

Chemical Communication Rules for One Frog Species

Anurans are known primarily for their use of auditory communication. Most other forms of communication are overlooked when considering this group of amphibians. This leaves us with many modes of communication not thoroughly explored. Many salamanders use chemical cues as one of their primary modes of communication, yet very little work has been done with frogs in regards to this mode. Their flashy auditory calls must be quite a distraction from other forms of anuran communication.

Bruce Waldman and Phillip Bishop published a study, "Chemical communication in an archaic anuran amphibian” that was performed from 1997-2000 concerning chemical communication in the frog Leiopelma hamiltoni. This species is very plesiomorphic and uses auditory calls only to frighten predators and not in a social context. This study showed that these adult frogs use chemical communication in a social context. These frogs were shown to use chemical signals to aid in self-recognition and in distinguishing between close neighbors, neighbors living close to the frog’s home range and between frogs that are unfamiliar to them. This study did not show what function such communication would serve. It did however speculate that such communication could be used to select for non-related mates or to allow related frogs to cooperate with one another. This species rarely strays from an established home range and so to optimize reproductive output it would be beneficial to be able to distinguish between related and unrelated frogs. Similarly to birds learning the songs of their neighbors, these frogs use chemical cues to learn who their neighbors are. This allows them to properly respond to unfamiliar frogs appropriately.

The Link to this article is: http://beheco.oxfordjournals.org/cgi/content/abstract/15/1/88

Posted by: Jess Bouchard
Chemical communication is easily disrupted and easily corrupted, especially by human activities. This form of communication seems to be a fit for this species, which have a small home range and do not stray far. What impact has human activity played in the decline of this species? This species is a protected species in and around New Zealand. Is this form of communication going out of style as a primary social communication mode, especially considering the amount of toxins and waste humans dump into the environment everyday. Hopefully more work can be done to uncover other species that use a similar communication method and also concerning how this effects the overall fitness of this species in this day and age.

3 comments:

  1. What do the frogs produce chemically to communicate to each other? What are the exact components and process of the communication? It is interesting to know that a chemical signal can help distinguish between family members and neighbors. I always thought frogs communicated verbally to each other not scare of predators. I am also curious as to how the frogs use their call to scare off a threat. It appears to me that it would attract a predator rather than scare it off.

    Carlos (Week 4)

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  2. So does the article suggest that chemical communication is plesiomorphic in frogs, and vocal communication is derived? I could be interested to know what this animal's phylogeny is. Yes, I just ended a sentence in a preposition.

    - Deysha Rivera

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  3. Thanks for your comments. The researchers suggest that the chemical cues could be genetically or environmentally based, probably a combination of the two. Fecal deposits were enough to convey some imformation, but these frogs are able to distinguish between themselves, their close neighbors and frogs unknown to them. That is why a genetic component is suggested. It would be interesting to expand upon this idea and try to collect more evidence to support it. Different food sources can also come through a signals. These frogs, and also most salamanders I believe have specialized glands that secrete amines and peptides that aid in chemical communication. As far as chemical communication being pleisomorphic, chemical communication evolved way before vocal communication in general. These frogs exhibit many pleisomorphic characteristics. Hamilton's frog, as does all of the four species of Leiopelmatidae, most closely resemble from the Jurassic period according to the article. The discovery of the prevalence of chemical communication in this family sheds light on how frogs may have communicated before vocal communication and it is also suspected that this mode is widespread throughout the anurans, not just more archaic species. And finally, a note on my big pet peeve...these guys are researchers , they should know that it is redundant to say "frogs and toads". Toads ARE frogs. It's like saying catholics and christians.

    post response...posted by: Jess Bouchard

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