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Introduction The Egyptian plover, Pluvianus aegyptius, is a type of wader. It is also known as the crocodile bird. It is the only member of the genus Pluvianus. This bird resides in tropical Sub-Saharan Africa [1]. The plover inhabits middle areas of lowland tropical rivers in Africa, including the Nile, Congo, and Niger Rivers [2]. The bird favors rivers with sandbars and slow-flowing waters. When the breeding season is over, the plover may be found in wetland sites but is avoids heavily forest areas and rarely seen near saltwater marshes. The plover prefers sandbanks mostly because it nests during the dry season where river levels are low. The eggs are placed in a hollow area and when the area is unattended, it covers the eggs with sand. To reduce the overheating of the eggs, the plover releases water from the belly plumage which cools the eggs. When the chicks hatch, they are able to run and feed themselves shortly after birth [1].
Relationship
The Egyptian plover shares a mutualistic relationship with crocodiles. Although a specific species is not identified, the Nile crocodile benefits from the relationship. The Nile crocodile is Africa’s largest crocodile and is found throughout Africa near rivers, lakes, swamps, and freshwater marshes [2]. Since it is a mutualistic relationship, both partners benefit. The crocodile is found basking on riverbanks with its mouth open. The plover notices it and flies over to clean the crocodile’s teeth. The relationship is similar to the cleaner fish. The fish eat the ectoparasites which clean the infected fish and the cleaner fish gets its food. The crocodile gets a dental floss and the plover receives food.
Cost/Benefit Analysis
As mentioned above, both species benefit from this relationship. The crocodile opens its mouth so that its teeth can be cleaned. When the food is stuck and not cleaned, the food begins to rot the teeth which may cause pain. The Egyptian plover takes care of the job as a dental floss. In return the plover gets food. This is not the only food source of the plover. It does eat insects, spiders, beetles, and other small organisms. Neither organism has a negative effect in this relationship. Maybe if the plover accidentally flossed deep, it could hurt the crocodile. Also the crocodile can probably eat the plover. However, none of these cases have been seen. Otherwise, there are not major costs seen in this relationship.
References:
[1] http://en.wikipedia.org/wiki/Egyptian_Plover
[2] http://what-when-how.com/birds/egyptian-plover-birds/
[3] http://www.angelfire.com/mo2/animals1/crocodile/nile.html
[4] http://en.wikipedia.org/wiki/File:Flickr_-_Rainbirder_-_Egyptian_Plover_(Pluvianus_aegyptius).jpg
[5] http://www.wolaver.org/animals/crocodile-plover.htm
You said in the blog the relationship between the plover and crocodile is similar to the relationship between the cleaner fish and client fish that come to get "cleaned", in that relationship there was a cheater fish, sabre-toothed blenny. This cheater fish has a negative impact on the cleaner fishes. Are there any sort of negative impacts on the plover? Maybe other crocodiles that take advantage of this mutualistic relationship?
ReplyDeleteIs there anything that the crocodile can do to attract the plover or increase its chances of being chosen to be cleaned? Or is the benefit so small that the cleanings just happen by chance when a plover sees a crocodile with its mouth open?
ReplyDeleteAlso, is there anything that the plover does to identify itself as a cleaner, since a bird in the mouth of a crocodile could easliy become dinner. Is there some kind of ritual or chemical that identifies the plover to the crocodile?
Unlike the cleaner fish cheats, there are not any negative impacts. There haven't been any cases of crocodiles taking advantage of the plover; however it can be a possibility.
ReplyDeleteThe crocodile just sits on the shore with its mouth open. Other than that, there aren't any other signals or attractions for the plover. The plover is the only bird that cleans the teeth of a crocodile, so it is the only bird that will get the cue of cleaning the teeth. Other birds will not understand why the crocodile is sitting with its mouth open, so other birds will not approach the crocodile.
Why is this being discussed its rubbish!!!!! there may have been the odd sighting of a bird near or around crocodiles. But there is no symbiotic relationship. A magpie can often be seen to land on a cows back, or in the case of our cat, come up and pinch food from the bowl if the cats being fed outside. they just sort of put up with certain things but all wont behave this way. Some people dont mind being surrounded with pigeons when eating thier sandwich while others hate them and chase them away and we dont get any benifit from pigeons that im aware of but they do get crumbs. So its nothing like the fish thing. Crocodiles as far as Im aware wont need thier teeth cleand as they are far apart- probably dont get food wedged in the spaces because of this, and grow all the time just keep getting new ones when the top bit wears or breaks!
ReplyDelete