|MadSci Network: General Biology|
Dear Ms. Gorey: What a fantastic question! I studied mate choice in seahorses in Dr. Sara M. Lewis' lab at Tufts University, which is likely why I was chosen to answer this question. The coronet of the seahorse, which is formed by the bony plates of the seahorse skeleton, doesn't serve any overt function. Seahorses don't, for example, use the coronet to ram each other or for capturing prey. There are, however, two possible uses for the coronet which have recently come to light. First, seahorses (Hippocampus spp.) make audible clicks while feeding. Work by SM Lewis' group (1) has shown that the coronet is involved in producing/ amplifying this sound. The clicks that the seahorses make may also allow them to communicate with one another or at least allow them to detect the presence of other seahorses nearby. Seahorses live in dense mats of sea grasses, and are well-camoflauged, which may make it difficult to find a mate. Audible clicks may overcome this barrier. Second, seahorses are unusual in the animal world in the fact that the males become pregnant. Male and female seahorses mate monogamously (2-5), a bond reaffirmed each morning by a quivering "dance" of greeting. Because they mate monogamously, it is important for a seahorses to choose a good mate. One of the parameters the female seahorses select on (and possibly vice- versa) is mate size. The larger the male, the larger his pouch is likely to be, and thus the more eggs he is able to incubate. A large mate is likely a more "fit" mate, to use the evolutionary term. If the coronet makes an individual seahorse appear larger, taller, then that individual may be selected over its competitors. In this way, a tall coronet might impart a selective advantage to the animal that possesses it, in the same fashion that a male peacock's long feathers impart a selective advantage to him. So, another way the coronet might serve a purpose is to provide a positive selective advantage to the animal that possesses it due to mate selection. I hope this answers your question. If it did not, or if you have more questions, please feel free to e-mail me at: firstname.lastname@example.org. Have a good day! Ingrid References: 1) Jones et al, Molecular Ecology 7(11):1497-1505, 1998 Nov. 2) Vincent et al, Animal Behaviour 50(part 6):1557-1569, 1995 Dec. 3) Masonjones and Lewis, Copeia (3):634-40, 1996 Aug 1. 4) Vincent, Animal Behaviour 49(1):258-260, 1995 Jan. 5) Vincent, Behaviour 128(part1-2):153-167, 1994 Feb.
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