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After our field trip to the Donnelly Wildlife Management Center, I was totally inspired by our first find. We caught not one, not two, but THREE Greater Sirens. Finding these Siren lacertina was so intriguing because they are not amphibians that you see too often. They tend to dwell in muddy, heavily vegetated Coastal Plains Wetlands across the south east. Considering their habitat, the siren has many specializations that has allowed it to successfully thrive in these conditions, one specialization being chemosensory. In this particular article that I read, Crawford et al. studied the Greater Siren's ability to detect predators, and they recorded their behavioral responses to determine if the siren could actually decipher how big of a threat the predator ac tually was. In natural settings, the mudsnake (Farancia abacura) and the banded water snake (Nerodia fasciata) are the Greater siren's naturally occurring predators. The mudsnake is a specialist who only eats salamanders while the banded water snake is a generalist and eats salamanders and a wider array of animals as well. Logically, a smart siren would be much more cautious in the presence of a mudsnake than they would in the presence of the banded water snake right? This is the threat-sensitive hypothesis in full effect.
The experiment in this article took greater sirens captured from the wild and tested their responses to kairomone cues from the mudsnake (specialist), the banded water snake (generalist) and also a hognose snake who is not naturally found in the Siren's habitat. Each siren was introduced to each species' kairomone and behavioral activities were recorded. The initial response to all introduced kairomones was gill-flushing. This is when the siren opens and closes it's mouth to flush water across it's gills. This tells the observer that the kairomone has been detected by the siren. Only when the mudsnake kairomone was introduced did the siren display reversing direction after cue detection. This tells us a TON! The Siren is amazing, it can tell when a predator is around and it can determine through the kairomone that the predator is releasing just how big of a threat that predator actually is. If that is not fascinating I don't know what is. Herps have ceased to amaze me!
I think that the sirens are an amazing and mysterious creature. As soon as we found them on our trip I knew my last blog was going to be about them. Then, when I went to do research I found that there really hasn't been much done on these mystical creatures. Is this my calling?!?!?!
Autumn Anthony
1 comment:
Very relevant - we've encountered both banded water snakes and mud snakes in that swamp. Sirens, beware!
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