Armadillidium

Pronunciation

How to pronounce Armadillidium: //ˌɑːrmədɪˈlɪdiəm//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

Summary

Armadillidium is a genus of terrestrial crustaceans commonly known as pill woodlice or roly-polies, recognized for their ability to roll into a ball as a defensive mechanism. They primarily feed on decaying matter and require moist habitats.

Physical Characteristics

Armadillidium are characterized by their ability to roll into a ball, a behavior known as volvation. They have a hard exoskeleton and lack a waxy cuticle, which leads to higher evaporation rates compared to other terrestrial arthropods.

Identification Tips

A. vulgare has a truncate, more trapezoidal telson, while A. nasatum has a rounded telson. When rolled into a ball, A. vulgare forms a perfect sphere while A. nasatum often has its tail sticking out. The scutellum of A. vulgare barely projects, while that of A. nasatum projects significantly.

Habitat

They are usually found in moist areas such as decomposing leaf matter and soil.

Distribution

2 species in North America, both introduced; over 300 species in Europe, most concentrated around the Mediterranean.

Diet

They chiefly feed on decaying organic matter such as leaves and decomposed wood fibers, with some consumption of lichens.

Life Cycle

Individual pill bugs typically live for two or three years, with females brooding eggs once or twice each summer. Up to over a hundred eggs can be brooded at a time in the marsupium.

Reproduction

The marsupium on the ventral side of the female pill bug provides nutrients and oxygen to the eggs until they hatch, which is akin to a live birth.

Ecosystem Role

Pill bugs play a role in the decomposition process by feeding on decaying organic matter.

Cultural Significance

Often referred to as roly-polies, pill bugs are commonly found in gardens and yards, where they contribute to soil health.

Collecting Methods

• Hand collection in moist environments
• Using pitfall traps

Preservation Methods

• Ethanol preservation
• Freezing for temporary storage

Similar Taxa

• Pill millipedes (Glomeris species)

Misconceptions

Pill bugs are often confused with pill millipedes and are mistakenly thought to be dangerous due to their resemblance to the venomous Mediterranean black widow spider.

Tags

• Armadillidium
• pill bugs
• woodlice
• ecology
• decay
• Mediterranean