Introduction:
Porcellio scaber or commonly known as ‘slater’, belong to the biological group Phylum; Arthopada and Class; Crustacea. Animals that are associated with this group include; most Crustacea, shrimp, crabs and lobsters. Slaters have become terrestrial, although this may differ in physical appearance. As they have recognisable dark grey flattened bodies, being about 17mm in size and have a rough exoskeleton. They also have a pair of prominent antennas and seven pairs of legs.
Slaters are generally found in moist areas in New Zealand, in a group rather than isolated. They inhabit moist areas as they can be found under rotten wood, logs, foresting areas and compost heaps. Slaters are omnivores or scavengers, as they feed on decaying vegetable matter and animal matter. The conditions they live in are damp, this is because they prefer to live in low light intensity, as they are negative phototaxis. They try to avoid and stay away from lighter conditions as they prefer darker conditions to reduce water loss and retain moisture. They favour conditions, which are high in humidity and cooler temperatures. Slaters favour these particular conditions due to them being prone to desiccation (drying out from water loss). As the slaters lack a water proof waxy cuticle, which makes their exoskeleton more permeable to water loss. By diffusion, the slater utilises its exoskeleton to absorb water vapour, generally done in excessively high humid conditions.
Slaters show the response of orthokinesis, when the temperature increases in the environment they are in, as they are more likely to move to a preferred temperature and spend less time in unfavourable conditions. They also show the response of positive thigmokinesis when the rate of movement of the slaters is decreased as their bodies have come into contact with another object, causing the clumping behaviour. Slaters are usually not found isolated, as they are commonly congregated into a group, so that slaters can utilise their clumping behaviour to reduce predation and water loss, often in low humid conditions as they favour high humid conditions. So by slaters using their clumping behaviour they are able to reduce the exposed surface area to prevent desiccation.
Humidity is significant to the slater as it helps with the reduction of desiccation and the conservation of moisture. These factors are dependent on the humidity level, as at low/ dry conditions they lose a lot of moisture due to them being in unfavourable environmental conditions, therefore promoting desiccation. While at high/damp conditions they reduce desiccation and are able to retain moisture as they are in favourable environmental conditions. My investigation is going to look at the preferred humidity for slaters, which will be the best to minimize desiccation.