Aplicación del análisis de los rasgos ecológicos (“traits”) de las presas para el estudio del comportamiento alimentario en peces bentóofagos: el ejemplo del espinoso (Gasterosteus gymnurus Cuvier, 1829)

摘要

We have used fourteen ecological traits of the macroinvertebrates present in the stomachs of the stickleback to try to obtain information on it’s feeding behaviour in the upper part of the Mi˜no basin (NW Spain). To this end, a principal components analysis was carried out, using the level of affinity of the taxa for the different categories of the traits through a fuzzy codification process. The results show that the stickleback is a bottom-feeder that feeds basically on benthic prey, but can also consume terrestrial prey on the surface, the Chironomid larvae being the most abundant prey (constituted 59.66% of the total). This species exhibited a generalist behaviour concerning some of the ecological traits of the prey (ex. ‘substratum’, ‘aggregation tendency’, ‘trajectory on the substratum and in the drift’, ‘agility’ or ‘body flexibility’). In other cases it showed a clear preference for prey with certain characteristics, such as taxa typical of areas where the velocity of the current is null or low (trait ‘current velocity’) or taxa available in the drift during daylight (trait ‘daily drift behavior’). The results obtained show that this type of analysis could be used on other bottom-feeder species, thus providing a more ecological approach to feeding studies.