The effect of group membership on hiding behaviour in the northern rock barnacle, Semibalanus balanoides

Citation
Ra. Mauck et Kc. Harkless, The effect of group membership on hiding behaviour in the northern rock barnacle, Semibalanus balanoides, ANIM BEHAV, 62, 2001, pp. 743-748
Citations number
43
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences","Neurosciences & Behavoir
Journal title
ANIMAL BEHAVIOUR
ISSN journal
0003-3472 → ACNP
Volume
62
Year of publication
2001
Part
4
Pages
743 - 748
Database
ISI
SICI code
0003-3472(200110)62:<743:TEOGMO>2.0.ZU;2-C
Abstract
Animals living in groups are thought to gain fitness through decreased pred ation risk, while often paying a cost in terms of increased competition in foraging. Thus, the balance struck between predator avoidance and foraging should be affected by group membership. For animals that avoid predation by withdrawing into a refuge (i.e. 'hiding'), such as the northern rock barna cle, Semibalanus balanoides, that balance should be particularly important since predator avoidance excludes foraging altogether. We tested the hypoth esis that barnacles living in groups should spend less time hiding when fac ed with a perceived threat than should solitary barnacles. We presented gro up-living and solitary barnacles with a simulated threat and measured hidin g time with the prediction that barnacles in groups would return to foragin g more quickly than solitary barnacles. Hiding time for group-living barnac les was significantly less than for solitary barnacles. We then manipulated barnacle group size with the prediction that an individual barnacle's beha viour would change based on group membership alone. We tested individual ba rnacles three times in an A-B-A design in which barnacles were tested in on e of two sequences, solitary-group-solitary, or group-solitary-group. We fo und that group membership had a significant effect on barnacle foraging beh aviour in that individuals emerged from hiding sooner when tested in a grou p than when tested alone. We conclude that, as predicted by optimality theo ry, group membership strongly affects foraging decisions by this refuge-usi ng animal. We argue that the proximate mechanism for such behaviour may inv olve a simple binary reaction to living in a group. (C) 2001 The Associatio n for the Study of Animal Behaviour.