Spatial and temporal patterns in the feeding behavior of a fiddler crab

Fiddler crabs consume the surficial microphytobenthos around their burrows during low tide. We studied the spatial and temporal feeding patterns in the species Uca uruguayensis by using sequences of digital pictures of feeding pellets accumulation. Data from 61 crabs, feeding without the interference of neighbors, were fitted to different models using Maximum Likelihood and Bayesian approaches. Initial feeding location was independent from the emergence location, and then, crabs continued holding a main feeding direction (clockwise or counterclockwise), suggesting a systematic mechanism that may avoid feeding over already processed sediment. Crabs used at least half of their potential feeding area, but these areas were heterogeneous. Both sexes developed similar feeding areas; however, females were faster and needed less time to feed than males, suggesting that males are time restricted. Our work also highlights the importance of incorporating other underlying mechanisms of the behavior of species into the study of feeding strategies.     

A pest is a pest is a pest? The dilemma of neotropical leaf-cutting ants: Keystone taxa of natural ecosystems

Leaf-cutting ants of the generaAcromyrmex andAtta are considered the principal polyphagous pests of the Neotropics Although some members of these genera are of economic importance, have a broad geographic distribution, and are extremely good colonizers, others are endemic and closely interact with native ecosystems. Control is generally practiced against any colony, irrespective of its taxonomic status. Indiscriminate control coupled with habitat destruction threatens endemic species with extinction, and, through habitat simplification, favors other pest species. As nests ofAtta are large, having several square meters of nest surface, the endemic taxa can be easily used as environmental indicators for natural ecosystems Likewise, the pest species can be used to detect environmental disturbance As these ants are keystone species and easily identified by nonspecialists, efforts should be made to integrate these into viable conservation programs