pupar

Pupar is a term used in entomology to describe the transition of a larva into the pupal stage, or the act of forming a puparium, the protective casing that encloses the pupa in many higher flies. The noun puparium refers to this hardened case, typically produced from the larval cuticle and, in Cyclorrhapha, the last larval skin forming a rigid capsule around the developing pupa. The process of entering the pupal stage within the puparium is called pupariation.

In species that form a puparium, such as many Cyclorrhapha flies, pupariation occurs after the final larval instar when hormonal cues trigger metamorphosis. The larva molts into the puparium, inside which the pupa develops and tissues differentiate until the adult emerges through a slit at the anterior end of the puparium.

Structure and ecology: The puparium is typically a hardened, often dark-colored capsule that provides protection against desiccation and predation. It may be buried in soil, concealed under debris, or attached to substrates, depending on the species and habitat. Pupariation timing is influenced by environmental factors such as temperature, humidity, and resource availability, affecting development rate and life history.

Applications and relevance: In forensic entomology, the age of puparia found on remains can help estimate the minimum time since death when temperature and other conditions are known. Pupariation is a key feature distinguishing the metamorphosis of certain fly lineages from other holometabolous insects, which form pupae in different ways.