Question

why do large Porcellio scaber move quicker than small P.scaber ( in relation to length)? can someome please attach a website as well as their answer.

Answer 1

Porcellio scaber

Porcellio scaber is a common woodlice and considered native to Europe.They prefer moist, dark areas preferably under a leaf litter, rocks, fallen logs in order to avoid dessication.

Physical description

They are ectothermic and have flat, elliptical shaped bodies, heavily plated, typically grey or deep blue.They can grow upto 17mm in length.Their bodies are segmented, bilaterally symmetrical, have 7 body segments ,each with pair of legs.

Their body is divided into 3 sections

• head
• pereion (thorax)
• pleon(abdomen)

Their weight varies depending in the water content. These isopods have warty body surface with 2 short tails.

They have compound eyes and 2 pairs of antenas - shorter pair (act as chemoreceptors) and longer pair(sensory hair like structure).

Motility, Communication and Perseption.

These wood lice have long antena with setae which sense movement and shorter antena which may function as chemo receptors.They also sense their environemnt through touch which causes reduced movement when in physical contact with the object.To attempt to find an envioroment where they lose less moisture and then stay there. P.scaber alter factors such as speed and rate of turning.

In a dry or hot environment, these woodlice have been observed increaseing speed and turn more often.In a moist, dark, cool environment they slow down dramatically and often stop altogether.

In order to avoid desiccation , most P.scaber exhibt thigmokinesis, slowing down or stopping when in contact with multilple surface.And due to the bilateral asymetrical leg movement which suggest that on the original turn, the legs on the outside of turn become relatively more tired, so end up being over powered by the legs on the inside of the turn causing it to turn the opposite way.

(http://animal diversity.org)

On a study done by Ivan Hadrian et al in 2015 ,The personality affects defensive behaviour of Porcellio scaber wherein individual behaviour patters of P.scaber was taken into consideration and found that there were no significant differences among body sizes of these isopod and it didnot affect the motility but various other factors including different postures was important to escape themselves from the predators.