Woodlice in general in NZ

Essay by shantanukHigh School, 10th gradeB+, July 2004

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One of the main species of woodlice found in New Zealand is "Porcellio scaber". This species must have arrived here along with the European settlers during the colonization.

Woodlice are mainly found in damp dark areas for example under rotting wood, in compost heaps and under rocks. All woodlice consist of 3 sections which are fused together. They also have seven pairs of legs. Woodlice have evolved from the aquatic crustaceans. They belong to the subphylum Crustacea. All woodlice breathe through very primitive lungs.

Woodlice prefer high humidity and cooler temperatures mainly because of the permeability of their exoskeleton to water and the loss of water from their respiratory pleopods. These preferences are behavioral adaptations to help reduce desiccation. Woodlice lack the waxy cuticle normally found on the exoskeletons of most cephalopods. This means that they are much more prone to desiccation (drying out due to excess water loss) than other members of the arthropoda such as insects and spiders.

As a result of this, much of their behavior is concerned with avoiding desiccation. The absence of wax or cutin means that the exoskeleton is permeable to water and so woodlice will rapidly desiccate in dry conditions. Conversely, in excessively humid conditions it may be possible for woodlice to absorb water vapor by diffusion through their exoskeleton.

Woodlice have primitive lung-like structures in two of their pleopods. These show up as two white patches on the lower side of their abdomen. The lungs open to the outside via a simple pore; this again means that water loss from their respiratory surfaces is likely to be greater than is the case in most insects.

Woodlice will try to reduce water loss by moving away from hot and/or dry areas and will therefore tend to congregate in more humid,