Boxer crabs induce asexual reproduction of their associated sea anemones by splitting and intraspecific theft.

Crabs of the genus have the remarkable habit of holding a sea anemone in each of their claws. This partnership appears to be obligate, at least on the part of the crab. The present study focuses on from the Red Sea holding anemones of the genus (family Aliciidae).

Retention of acoustic conditioning in St Peter's fish Sarotherodon galilaeus.

Groups of St Peter's fish Sarotherodon galilaeus were trained during 28 days of classical conditioning to respond to an acoustic signal by approaching a feeder. Their ability to retain the acoustically conditioned behaviour was tested after eight different intervals ranging from 12 to 188 days from termination of training. Retention tests comprised 7 consecutive days of retraining and the fish response was compared with that of naive fish.

Generalization and discrimination of positive and negative acoustic stimuli in the common carp (Cyprinus carpio).

Groups of common carp (Cyprinus carpio) were trained for 33 days to discriminate between two acoustic signals differing in frequency and temporal pattern. One signal (positive stimulus) was reinforced by food, while the other (negative stimulus) was not rewarded. When exposed to 3 positive and 3 negative stimuli per day (training Paradigm 1) the fish responded similarly to the two signals.

Intersexuality and behavior in crayfish: the de-masculinization effects of androgenic gland ablation.

In crustaceans, male differentiation and primary and secondary characteristics are regulated by the androgenic gland (AG). In gonochoristic crustaceans, the AG is also linked to intersexuality. Whereas the co-occurrence of various male and female characteristics has been demonstrated in intersex crustaceans, little is known regarding sexually dimorphic behavior patterns in such individuals.

Inducible reproductive plasticity of the guppy Poecilia reticulata in response to predation cues.

Predation has long been described as one of the major driving forces in evolution. Guppies (Poecilia reticulata) from natural populations exposed to different predation pressures, were found to have different life history traits. Reproductive plasticity in response to direct predation cues has mainly been reported for invertebrates.