Woodlice are the only completely terrestrial crustaceans and live mainly under old stumps or under dead leaves, to protect themselves from the sun. They are equipped with a rigid, segmented exoskeleton, from pale yellowish-brown (rather in young people) to blackish to slate gray. Their shell is sometimes almost transparent. It is composed of limestone, calcium phosphate and chitin. ​ The body of woodlice is made up of different metameres associated in three different parts: the head, thorax and abdomen. The head, or cephalon, carries the sensory organs (compound eyes, two pairs of antennae, one of which is very small and difficult to observe) and the mouthparts. The thorax, or pereion, is made up of 7 segments. The ventral part of each segment bears a pair of walking legs. The woodlice thus has 14 legs. This easily observable criterion allows it to be differentiated from insects. The abdomen, or pleon, composed of 5 segments, carries the respiratory and reproductive organs. Woodlice breathe through gills contained in small pouches filled with water. These pockets are limited by thin membranes allowing the exchange of respiratory gases with the atmosphere.

• Food Woodlice are scavengers that feed on decomposing plant matter. They thus contribute to the recycling of necromass and allow a more rapid return of nutrients to the soil. They can also attack living plants, roots, fruits, etc., but they do not represent a threat to crops. In breeding, you can give them all types of fruits and vegetables. They also love fish glitter. They also need a source of calcium to develop their shell, so cuttlebones are widely used in woodlice breeding.

• Cycle de vie et reproduction

• Woodlice live between 2 and 4 years, moulting monthly. They reach sexual maturity at the age of 3 months to 1 year, depending on the species. ​ A female woodlice maintains fertilized eggs below her body in a brood pouch called a marsupium. After a month of incubation, the mother then appears to “give birth” to her offspring (see video opposite).

​

Behavior Some species of woodlice can roll up into a ball when they feel threatened, leaving only their armored back exposed (volvation). They are distinguished from glomeris (centipedes) by the greater number of tergal plates when they are in a ball. Woodlice can form large aggregates that allow them to resist desiccation for longer. This aggregation behavior observed in woodlice is a first step in the evolution of sociality (demonstrated in Porcellio scaber. Some species restricted to deserts, for example Hemilepistus reaumuri, live in families or in pairs and raise their young in a burrow .

 

Habitat

 

Woodlice are lucifuge and usually nocturnal. This drives them to seek out dark, damp places which they colonize in groups. They are found, for example, under leaves or bark, in dead wood, in rocky crevices or in cellars and in the trumpets of death. A study of soil macroinvertebrates in Mediterranean-type forest and southern Russia, using 144 intact soil samples (76 cm2 each), showed an average isopod abundance of 166.3 ± 16.0 indiv./m2 (12% of total macrofauna abundance in these cases), with an average biomass of 3.5 g/m2 (approximately 21% of total macrofauna biomass). Three genera of woodlice (Armadillidium, Cylisticus and Trachelipus) occupied the sampled sites. The last two genera, Cylisticus and Trachelipus, accounted for 93% of the total isopod populations. The researchers also noted a very heterogeneous spatial distribution (the authors recommend at least 40 samples to estimate the abundance of isopods in a brown forest floor). Their distribution seems to be influenced in particular by the mass of the litter, its food content, its pH (rather neutral to very slightly acidic; pH: 6.79), good water retention (70.9%).

Overall, regarding the environments they occupy, we can distinguish species11: halophiles, e.g. Ligia oceanica. In fact, woodlice come directly from marine isopods, without having gone through a stage linked to fresh water. Thus, a large number of species are halophilous, and do not move far from the sea shore, feeding in masses of algae or on rocks. coastal areas, p. ex Halophiloscia hirsuta; sabulicoles, living in the sand of the banks, for example: Porcellio scaber, Tylos latreilli; malaria, linked to marshes, e.g. Ligidium hypnorum); practical, linked to meadows, p. ex Chaelophiloscia elongata, Trachelipus rathkei; silvicultural, specific to forests, e.g.: Trachelipus ratzeburgi, Armadillidium pulchellum; humicous, living in humus, dead leaves, rotten wood, p. ex: most Trichoniscus and Haplophthalmus; dead tree stumps; corticicoles: the barks can become refuges, especially in winter, e.g. ex the rough woodlouse (Porcellio scaber); alticulture, such as Porcellio pyrenaeus; calcicoles, such as Porcellio spiniformis, in the causses; troglophiles, inhabiting dark places like cellars, like Chaetophiloscia dentiger, or the underground environment like Androniscus dentiger and Oniscus asellus; cavernicoles, living in caves, always depigmented, and without ocular apparatus, such as Finaloniscus, Alpioniscus, Scotoniscus, Spelaeonethes; endogenous, that is to say living in the soil, often relict species which have entered the soil to survive and often localized; myrmecophiles, that is to say living in association with ants, such as Platyarthrus, depigmented and blind; synanthropes, living in the vicinity of humans; in gardens, manures and composts, houses, sheds, such as Oniscus asellus, Porcellionides pruinosus, Porcellio scaber, Porcellio dilatatus, Porcellio laevis, Cylisticus convexus, Armadillidium vulgare. #Exterminator #Laval, #Exterminator #Montreal