Counting on Numbers-Numerical Abilities in Grey Bamboo Sharks and Ocellate River Stingrays.

Over the last decade, studies examining the cognitive abilities of fish have increased, using a broad range of approaches. One of the foci has been to test the ability of fish to discriminate quantities of items and to determine whether fish can solve tasks solely on the basis of numerical information. This study is the first to investigate this ability in two elasmobranch species.

Holding tight to feathers - structural specializations and attachment properties of the avian ectoparasite (Diptera, Hippoboscidae).

The louse fly is an obligate blood-sucking ectoparasite of the common swift As a result of reduction of the wings, is unable to fly; thus, an effective and reliable attachment to their host's plumage is of utmost importance. The attachment system of shows several modifications in comparison to that of other calyptrate flies, notably the large tridentate claws and the dichotomously shaped setae located on the pulvilli. Based on data from morphological analysis, confocal laser scanning microscopy, cryo-scanning electron microscopy and attachment force experiments performed on native (feathers) as well as artificial substrates (glass, epoxy resin and silicone rubber), we showed that the entire attachment system is highly adapted to the fly's lifestyle as an ectoparasite.