Question

3 Place a living pill bug in a petri dish or a sheet of paper and record its locomotion and behavior. Description of pill bug locomotion. Description of pill bug behavior.

Answer 1

The pill bug belongs to the Kingdom Animalia, Phylum Arthropoda, Class Crustaceae and Order Isopoda. To understand this experiment it is important to have some knowledge of the organism being observed. The pill bug is an isopod. The pill bug is made up of three body parts. They are the head, thorax, and abdomen. This organism has two pairs of antennae (one prominent and one inconspicuous), simple eyes, seven pairs of legs, seven separate segments on the thorax, and paired appendages at the end of the abdomen called uropods. The colour varies from dark grey to white with pattern or white without pattern. Male and female pill bugs differ in that a female has leaf-like growths at the base of some of its legs. The purpose of these pouches is to hold developing eggs and embryos. Males differ in that the first two appendages on their abdomens are elongated copulatory organs. The immature isopod looks like an adult, save for its size, proportion, colour, and sexual development. The pill bug is of the Order Isopoda. Isopods feed on dead or decaying plants or animals. Some isopods may eat living plants. They breathe with gills, and therefore their habitats are places of high humidity. During the day, pill bugs hide in moist places, such as under stone and bark. The organism being observed reproduces on land instead of in water. The eggs develop in a brood pouch filled with fluid. Pill bugs are known for their defence mechanism of curling up into a tight ball.

Ethology is the study of animal behaviour. An animal’s behaviour is its response to sensory input. There are three types of behaviours: orientation, agonistic, and mating.

Orientation behaviours take the animal to its most favourable environment. Taxis is when an animal moves toward or away from a stimulus. Taxis is often characterized by light, heat, moisture, sound, or chemicals. Kinesis is another type of movement that involves orientation. Kinesis is a movement that is random and doesn’t involve a stimulus. So an animal would respond to light by moving everywhere in random directions.

Agonistic behaviour is when animals respond to each other in aggressive or submissive movements. Like the hair on dogs backs when they get ready to fight. Mating behaviours are activities that involve finding, courting, and mating with a member of the same species. An example would be a peacock fluffing up its feathers to attract females.

Pill bugs also exhibit changes in behaviour when placed in a petri dish or a sheet of paper. If the paper or dish is wet on one side and dry on the other , we observe that the pill bugs will prefer the wet side to the dry side of the petri dishes because they are used to living in dark moist conditions, such as under rocks or in rotting trees. The bugs preferred it in the wet conditions. They probably like it there because they live in place like that, under rocks or in trees or just in the soil. That is probably the only way they can keep cool and obtain moisture. Pill bugs show taxis movement to avoid light and kinesis to locate moisture. They randomly move in different directions to locate humid and wet surfaces.