Julus

Julus is a genus of millipedes in the family Julidae, order Julida, class Diplopoda. It comprises numerous species found primarily in Europe and western Asia, with some records in North Africa and a number of introduced populations elsewhere. Members are elongate, cylindrical arthropods with many body segments. Most species bear two pairs of legs on each body segment, giving a slow, looping gait characteristic of julid millipedes. Coloration is variable, typically brown to dark, with species-level patterns that aid in identification.

Ecology and diet: Julus species are detritivores, feeding on decaying plant material, leaf litter, and fungal growth. They inhabit moist microhabitats such as the leaf litter layer, compost, under stones, and within logs. They are predominantly nocturnal and rely on ambient humidity to limit water loss.

Reproduction and development: Reproduction is sexual. Males produce spermatophores that are transferred to females during courtship. Females lay eggs, from which juveniles hatch with fewer segments and legs and grow through molts to reach adult size. Development does not involve dramatic metamorphosis; juveniles resemble small adults.

Taxonomy and notes: The genus Julus has undergone revisions as taxonomists refine species boundaries and move species to related genera. Identification relies on morphological characters, especially structures of the male genitalia (gonopods) and other features. Julus has a long-standing presence in European millipede taxonomy and is commonly cited in taxonomic and ecological studies of julid millipedes.