represent an all-out effort to overcome the disease, i.e. all the available
resources are allocated to fight the infection [2,3]. Moreover, behavioural
changes may also arise as adaptive, facultative responses of
hosts that serve to reduce infection loads or mitigate the effects of
parasites [4,5]. A reduced interaction with conspecifics, for instance,
may function in minimizing, in social species, the risk to infect other
members of the group [4] or, in more solitary ones, the contact with
other infected individuals and, thus, in avoiding further complications
for already sick animals [6]. In some cases behavioural changes may
also constitute an adaptive manipulation of the host by the parasite,
which accrues fitness benefits as a result [7]. Yet, despite the increasing
interest in behavioural responses to infection on an adaptive perspective,
studies aimed at understanding the physiological and behavioural