BEHAVIOR AND TIME ALLOCATION OF THE BURROWING SHRIMP CALLIANASSA-SUBTERRANEA (DECAPODA, THALASSINIDEA)

The behaviour and allocation of time of the endobenthic shrimp Callian assa subterranea from the central North Sea was studied in the laborat ory. Animals were allowed to construct a two-dimensional burrow in lar ge transparent sediment filled cuvettes tailored to their body width. The behaviour of the animals was found to consist of 12 behavioural st ates which were described in an ethogram. The allocation of time of an imals in cuvettes was recorded to the nearest 0.1 a during 1 or 2 h ob servation periods randomly distributed over the day. All records were statistically tested for their validity with respect to visibility of the animals studied. The behavioural states were grouped into six clas ses using a type of Markov-chain sequence analysis: Wandering, Resting , Burrowing, Surveying, Grooming and Ventilating. An average time budg et of 10 animals based on 98 valid 1 h protocols shows that C. subterr anea spends 27.4+/-2.2% (SEM) of the time Burrowing. This is a little more than 40% of the time the animal is active. Wandering and Grooming each take about half that amount, with 12.6+/-0.9% and 14.9+/-1.4% re spectively. Ventilating takes 8.6+/-1.5% and only little time is spent Surveying the burrow (2.6+/-0.4%). The animal is Resting during 33.9/-2.4% of the time. Circumstantial evidence indicates that feeding is part of the burrowing behaviour. No major periodicity in the behaviour of C. subterranea was encountered.