Investigation into the Factor of Light and Dark Affecting Woodlice

Investigation into the Factor of Light and Dark Affecting Woodlice

Predictions

It was expected that a woodlice would prefer a damp, dark, but

moderately warm surrounding. Normally one would expect to find slaters

under logs or concrete slabs in one's garden. Under these large

objects, the sun cannot reach directly; therefore it is darker, damper

and colder than the surroundings. Nevertheless, in winter we do not

see woodlice crawling around very often, and, also at night, it may

actually be warmer under such objects, because it looses heat more

slowly, so I predict that the woodlice would prefer a dark, damp and a

temperature of around 15oC. (The ground temperature of a typical

Scottish day). This preference to dark and damp surroundings is mainly

due to woodlouse's inefficient water-storage system. A woodlouse, if

exposed to heat or light for too long, can die due to the dramatic

loss of water. They prefer a moderate temperature, because they are so

small, and can be damaged by frost if they are exposed to the extreme

of cold, but they don't want such a high temperature, either, because

they would start loosing too much water. I would also expect the

woodlouse to prefer a surrounding of slightly higher pressure (1.05 ~

1.1 atmosphere), because water evaporates more slowly under a high

pressure. However, this is not investigated in this experiment due to

the nature of the choice chamber.

Equipment/Apparatus

10 woodlice, a choice chamber, a piece of muslin net, water, ice, a

kettle (to produce hot water).

Variables

There are three small experiments in this report and the variables and

constants are:-

Nr.

Variable

Constant

1

The humidity of the air

The temperature of the surroundings

The luminosity

The time allowed for woodlouse to settle

The number of woodlouse

2

The temperature of the air

The humidity of the air

The luminosity

The time allowed for woodlouse to settle