Rough Limpets (Lottia scabra) resting in their home scars.
Look closely at the three largest limpets and how they fit into the depressions in the rock. When submerged at high tide, the limpets will crawl around to graze on algae on the rock, but they will return to their individual home scars as the tide falls. Using a close-fitting home scar might help reduce water loss when the limpets are exposed to air during low tide.
P.S. I showed another fun example of a limpet home scar back in 2018 — see "Headed home" on 19 May 2018.
Happy Holidays to all!
You got me curious about how the scar forms, but the explanation I read -- that the shell wears away the rock over time -- seems incomplete, since the shell is only touching the rock at its edge.
ReplyDeleteHi, John!
ReplyDeleteI might need to put together a longer post with some more info, but your observation is correct -- the shell alone isn't responsible for the formation of the home scar. Research done in the 1980s showed that glands in the limpet's foot (and in the mantle) produce acidic secretions.
This is from Lindberg, D.R. and K.R. Dwyer. 1983. The topography, formation, and role of the home depression of Collisella scabra (Gould). Veliger 25: 229-234.
They also propose that the home scar isn't as much about preventing desiccation as it is about withstanding dislodgement (e.g., by waves or by predators).
Thanks for the comment and astute observation!
Jackie
WOW! So fascinating! Thanks, John, for your comment, making our wonder of the post even greater!
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