The Main Limpet Page,
Your Source for all Things Patellish !!
Above is a typical specimen of the common intertidal limpet, Patella vulgata. The species varies a lot depending whereabouts on the shore you find it, and there is much about this elsewhere on this site. But, before you go there, this is where to find out about the general biology of Limpets of this Genus.
FEEDING
Patella limpets feed on algae, many kinds of which grow on the rocks here. They have a very substantial rasping tongue. In fact, many intertidal molluscs possess such a device and Newell (1970) gives a very good account of all the different sorts found. That possessed by Patella (and Patina) is called a DOCOGLOSSAN tongue (not much on the web on this but you might try here and here.
They apply this tongue to the rocks and draw it across them like a rasp. The teeth are known to be very hard indeed, an adaptation to this usage.
The large numbers of limpets found on a typical shore, all rasping away like this, is thought to have a major effect on algal growth. It would appear that limpets are an important BIOTIC factor in influencing the distribution of algae on such a shore. There is much more on this here.
REPRODUCTION, The establishment of zonation
Like many organisms of the shore, limpets have planktonic larvae which have to settle on rock surfaces in order to mature.
Patella vulgata become sexually mature as males aged about nine months. Sex change may occur at one year, commonly at two to three, occasionally later and some limpets never become female. Spawning is believed to be induced by rough seas and onshore winds. Eggs (160µm in diameter) are broadcast singly and fertilized externally. They are dark green in colour due to the presence of a pigment called chromoprotein Y (Fretter & Graham, 1974). The trochophore larvae has a pelagic life of about 2 weeks and then settles on rocks at a shell length of about 0.2mm. Newly settled spat are usually found in rock pools or permanently damp situations. Recruitment fluctuates from year to year and from place to place and Bowman (1981) has pointed out that traditional statements about patellid breeding seasons are not universally valid for the British Isles. Patella vulgata is a winter breeder only in southern England, in the north of Scotland it breeds in August and in north-east England in September. (From: www.marlin.ac.uk/index2.htm?demo/Patvul.htm)
MOVEMENT, The maintenance of zonation
LIMPETS AND THEIR ENVIRONMENT
Temperature