Previous agonistic experience determines both foraging behavior and territoriality in the limpet Lottia gigantea (Sowerby)

Abstract

Lottia gigantea, the owl limpet, is an algal gardener. Territorial individuals actively defend gardens, which consist of cleared areas in the intertidal zone upon which a thick algal film develops and upon which the territory holder feeds. Smaller, nonterritory holders raid these gardens and graze the algal film. Territorial individuals must obtain an adequate ration without compromising the productivity of the garden. In contrast, a nonterritory holder grazing on another limpet’s territory must obtain an adequate ration before it contacts the territory holder and is driven off. In the laboratory, replicate sets of 10 limpets were trained to behave territorially and nonterritorially. Training mimicked natural encounters between territorial and nonterritorial L. gigantea. Limpets given territorial training left significantly (t 4.92, df 9, p .00041) more algal cover behind when grazing (on average 71%) than did limpets trained to be nonterritorial (on average 50%). Territorial limpets seldom grazed over the same area more than once (4% of the grazed area). In contrast, nonterritorial limpets frequently foraged over an area more than once; of the area grazed, 20% had been visited more than once. Previous agonistic experience determines both territorial behavior and foraging strategies, two of the critical behaviors necessary for successful gardening behavior. Nonterritorial limpets maximize consumption per unit area, whereas territorial limpets appear to forage prudently, leaving a significantly greater proportion of the plant biomass behind. Key words: foraging, gardening, grazing, limpets, Lottia gigantea, territoriality. [Behav Ecol 13:467–471 (2002)]