The abdomen of the crayfish is segmented and flexible. Bend the abdomen back and forth and observe how each segment moves. Count the number of segments on the abdomen. Hint: bending it will show you were the segments are separated. How many segments are on your crayfish? The Appendages Locate the chelipeds the claws. Gently manipulate the cheliped to determine the direction in which the appendage can bend. How many joints are there on a single cheliped? Two compound eyes provide excellent vision , except in some cave-dwellers that live in perpetual dark and are virtually blind.
Below the rostrum are two pairs of mandibles the jaws and three pairs of maxillipeds, which are small appendages that direct food to the mouth. The second pair of maxillipeds facilitate gill ventilation by swishing water through the banks of gills located at the base of each pereiopod on the sides of the carapace in the gill chambers. We also tested to see if other appendages could provide tactile information to compensate for antennal loss.
Input from the chelae did not affect the turning behaviour of crayfish in the maze. Abstract Appendages are important sources of sensory information for all animals that possess them but they are commonly damaged in nature. August 29, Fariss Samarrai , farisss virginia. Look closer, and you will see them feeling around with their legs and flicking their antennules — the small, paired sets of miniature feelers at the top of their heads between the long antennae.
Both are used for sensing the environment. The long antennae are used for getting a physical feel of an area, such as the contours of a crevice. The smaller antennules are there to both help the creature smell for food or mates or dangerous predators and also to sense motion in the water that also could indicate the presence of food, a fling or danger.
0コメント