Here we investigate the behavioural and immunological responses
in the common octopus immune-challenged with E. coli LPS. We evaluate
basal levels of circulating haemocytes and serum lysozyme activity,
and any detectable variation due to LPS challenge or merely to animals'
manipulation (including anaesthesia and haemolymph sampling) and
injection (sham-injected animals), also discerning eventual genderrelated
differences. Moreover, pairs of octopuses, composed of an LPStreated
individual and of a sham-injected one, are observed, before
and after the injection, in both isolated condition and that with reciprocal
visual contact allowed. In the sight-allowed condition we also focus
on the time spent interacting with the other individual of the pair.