Evidence of ‘sickness behaviour’ in bats with white-nose syndrome

Many animals change behaviour in response to pathogenic infections. White-nose syndrome (WNS) is a fungal skin disease causing rapid declines of North American bats. Infection with Pseudogymnoascus destructans causes hibernating bats to arouse from torpor too often, potentially causing starvation. Mechanisms underlying increased arousals are not understood but fungal invasion of the wings could trigger thirst to relieve fluid loss or grooming to relieve skin irritation. Alternatively, bats might exhibit ‘sickness behaviour’, a suite of responses to infection that save energy. We quantified behaviours of healthy and experimentally inoculated little brown bats (Myotis lucifugus) that could reflect active (i.e., drinking, grooming) or inactive (i.e., sickness behaviour) responses to infection. Infected bats groomed less and were less likely to visit their water dish compared to controls. These results are consistent with research suggesting that P. destructans causes sickness behaviour which could help bats compensate for energetic costs associated with infection.

Prior Residence Effect in the Dart-Poison Frog, Dendrobates Pumilio

Each of 32 male, Dendrobates pumilio (red phase) were allowed to establish a territory in one half of a 40 liter aquarium. Each enclosure contained a substrate of Sphagnum, a potted plant, and a water dish. Males occupying the same aquarium were prevented from seeing one another by an opaque barrier. In the first experiment, residents were presented with a conspecific intruder matched for size and color. Based on a numerical index of aggression, residents were consistently dominant over intruders. When reciprocal trials were conducted, the results were reversed (i.e. residents were dominant over males to which they previously had been subordinate). The success of resident males was not influenced by the size of conspecific intruders. In addition, residents consistently dominated a sympatric confamilial intruder (Phyllobates lugubris). Removal experiments revealed that resident males recognize and defend their enclosures after 3, and to a lesser degree, 6 days of isolation. We also examined the effect of territorial markers on the prior residence effect by stepwise removal of the plant and Sphagnum. Residents aggressively defended enclosures in both experiments. When Sphagnum was removed from the resident's enclosures and placed in a previously unused aquaria, 7 of 10 males exhibited dominance over conspecific intruders.