3 Things About Woodlice

3 Things About Woodlice

General

Woodlice are detrivores that eat rotting matter, waste and debris such as carrion, degrading wood, fungi like mould, fruit, decaying leaves, animal faeces and mildew; they can also eat via coprophagy. Some of these materials help with copper supplementation to the blood, as they hold haemocyanin instead of haemoglobin - which have a similar function but are comprised of copper instead of iron.

These crustacean isopods are decomposers, composters and nutrient recyclers for soil quality - also helping environments for a long time with a ~3 year lifespan - while meaning no harm either (though people could have allergies to the mites they carry).

They are more active at night, otherwise hiding in dark, cool, damp areas, including compost heaps and under wood or rocks during day.

Females are marsupials, possessing pouches on their underside - a single layer of skin under the thorax - which can hold eggs and newly hatched woodlice (called 'manca') for a few days first.

Desiccation and Aggregation

Woodlice are highly susceptible to dehydration and moisture loss (desiccation) since their exoskeleton alone already has high cuticular permeability that facilitates rapid water loss, never mind evaporation from the mouth or anus. Therefore, their need for a damp environment is emphasised. It's best to be bigger, to hold more water content and have a thicker exoskeleton to minimise loss.

Aggregation (grouping) protects against desiccation by over half in large groups, where increases in protection will be exponential as small group numbers rise - but naturally will stagnate with more and more individuals. Aggregation also aids circumstances involving reproduction, defence against predators, shelter, coprophagy and the acquisition of symbionts like gut bacteria.

Body and Exoskeleton

The woodlouse exoskeleton is their armour, yet a lot of species, e.g. common woodlice, still retain flexibility to accommodate for 'conglobation' (rolling into a ball) as a response to a perceived threat rather than biting.

Their ball form covers vital organs, increases the potential for camouflage in their dark habitats, and even roughly halves water loss in dry and/or humid environments. Pertaining to anti-predator function, males hold the ball shape for longer in the detected presence of a predator e.g. by pheromones. They are seemingly more attuned, considering survival instinct, than females, as they're inherently exposed to predator risk more whilst trying to find food and mates.

Instead of urination, woodlice release ammonia gas through the exoskeleton, which can be potent in large groups. What's more beneficial concerning odour, however, is their spider repellent - chemical properties which can get released by the tegumental lobe glands when attacked by a spider (probably their main predator). It further contributes to their distastefulness, where the extent depends on the glandular development.

Most woodlice have pleopodal lungs, which are a derivative of their gills after evolving from being aquatic; depending on the species, they can have multiple pairs. They reside in the hindlimbs and are almost always enveloped in a thin layer of water, which they collect and conserve, where oxygen gets absorbed. Although, this area loses water multiple times faster than the dorsal/ventral surfaces (except holding less water overall), so they could suffocate when dry.

A method of obtaining water other than oral drinking or through food involves the 'uropods'. They are like mini rear antennae that can be squeezed together to form a tube for capillary water absorption - to moisten the body tissues and lung surfaces. Whereas, the reverse is possible in excess; for instance, if one gets hit by a raindrop (akin to a massive tank of water poured on a person), water can get expelled for a dry surface to absorb the water.