Maze learning and memory in a decapod crustacean

Spatial learning is an ecologically important trait well studied in vertebrates but only in a few invertebrates and poorly understood in crustaceans. We explored the ability of European shore crabs, Carcinus maenas, to learn a complex maze over four consecutive weeks using food as a motivator. Crabs showed a steady improvement in their ability to learn and use the maze to find food during this conditioning period. Improvements were seen both in the time taken to find the food and in a reduciton in the number of wrong turns taken before the food was located. Crabs also clearly showed the ability to remember the maze. When we returned them to the maze following a two week break, but without any food in the maze, they all returned to the end of the maze in under eight minutes. Crabs that had not been conditioned to the maze took far longer to reach the end and 42% of individuals did not get to the end of the maze at all during a one-hour study period. Our study provides an initial description of spatial learning in the European shore crab. Bettering our understanding of this adaptive trait will develop our understanding of resource exploitation by benthic crustaceans and their ecological roles

Muscle precursor cells in the developing limbs of two isopods (Crustacea, Peracarida): an immunohistochemical study using a novel monoclonal antibody against myosin heavy chain

In the hot debate on arthropod relationships, Crustaceans and the morphology of their appendages play a pivotal role. To gain new insights into how arthropod appendages evolved, developmental biologists recently have begun to examine the expression and function of Drosophila appendage genes in Crustaceans. However, cellular aspects of Crustacean limb development such as myogenesis are poorly understood in Crustaceans so that the interpretative context in which to analyse gene functions is still fragmentary. The goal of the present project was to analyse muscle development in Crustacean appendages, and to that end, monoclonal antibodies against arthropod muscle proteins were generated. One of these antibodies recognises certain isoforms of myosin heavy chain and strongly binds to muscle precursor cells in malacostracan Crustacea. We used this antibody to study myogenesis in two isopods, Porcellio scaber and Idotea balthica (Crustacea, Malacostraca, Peracarida), by immunohistochemistry. In these animals, muscles in the limbs originate from single muscle precursor cells, which subsequently grow to form multinucleated muscle precursors. The pattern of primordial muscles in the thoracic limbs was mapped, and results compared to muscle development in other Crustaceans and in insects