Donax parvulus Philippi, 1849 Little Coquina

Donax parvulus Philippi, 1849 Little Coquina

In sand, Little Talbot Island, Duval County, Florida December, 2002 (about 4 mm.)

Donax parvulus With Hydroid

    During the summer and fall months a significant portion of the Donax found on northeast Florida beaches have a hydroid "plume" attached to the posterior aspect of the shell (the short end; the upper end when burrowing; the end with the siphons). Over the years this phenomenon has been a continuing source of amazement to those observing it for the first time and has generated many questions. A study of the sibling species Donax fossor indicates predation by Neverita duplicata (Shark Eye; Moon Snail) was affected by the presence of  a hydroid colony. Donax without a hydroid colony were drilled more frequently than those possessing it, which suggests that the Donax benefits from the hydroid by way of predator deterrence. The reduced predation supports the case  that this symbiosis is an  instance of mutualism.  Also see Donax variabilis Say, 1822 with hydroid

Dougherty, J.R. and M. P. Russell, 2005. The association between the coquina clam Donax fossor Say and its epibiotic hydroid Lovenella gracilis Clarke. Journal of Shellfisheries Research. 24: 35-46. [http://findarticles.com/p/articles/mi_m0QPU/is_1_24/ai_n13807881]

Donax parvulus With Hydroid
Minus tide, Little Talbot Island, Duval County, Florida 4/17/2012
Donax parvulus And Donax variabilis Comparison
Donax parvulus and Donax variabilis comparison
Donax parvulus - In muddy sand, Big Talbot Island, Duval County, Florida
Donax variabilis - In sand, Little Talbot Island, Duval County, Florida
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