Vision and Mating Behavior in Limulus

Abstract

Modulation of sensory function can provide a key for understanding the organization of sensory systems. This is indeed the case for the visual system of the horseshoe crab Limulus polyphemus. Large fluctuations in sensitivity occur every day in the lateral eyes of this animal. They are generated by nerve signals transmitted from a circadian clock located in the animal’s brain (Barlow, Bolanowski, and Brachman 1977; Kaplan and Barlow 1980; Barlow 1983). The clock’s signals can increase lateral eye sensitivity by as much as 100,000 times at night (Barlow, Bolanowski, and Brachman 1977; Barlow, Chamberlain, and Kass 1984).