Sarcophaga crassipalpis

Sarcophaga crassipalpis is a species of flesh flies (insects in the family Sarcophagidae.

It is a common laboratory animal used in the study of gene expression and the study of diapause in insects.[2]

Sarcophaga crassipalpis conforms to the basic bilateral symmetry body plan for arthropods and insects by possessing jointed-appendages, a sclerotized external cuticle, and an internal muscular system that functions as levers for movement.[3] The six legs possess a tarsus, or foot, with a pair of claws for gripping rough surfaces. Beneath the claws is a fleshy, glandular adhesive pad called a pulvillus, which is used on smooth surfaces.[4]

Sarcophaga crassipalpis is an insect in the order Diptera, meaning “two-winged”. As with other flies, S. crassipalpis has one pair of wings used for flying. Posterior to the wings is a small pair of knob-like structures (called halteres), which function as organs of balance.[5]

Like other dipterans, S. crassipalpis reproduces utilizing complete metamorphosis, i.e. the life cycle consists of the following stages: egg, larva (called a maggot), pupa, and adult.

Most notably, S. crassipalpis will enter diapause under very specific environmental stimuli. Photoperiod exposure received by embryos in the uterus is one factor in initiating diapause.[6] It is sensitive to specific environmental stimuli in its early larval stage and then enters diapause as a pupa. Sarcophaga crassipalpis enters an overwintering pupal diapause in response to cues of a short day-length received during late embryonic and early larval life.[7] Diapause in S. crassipalpis is not a complete cessation of gene expression. It is a separate developmental pathway that is expressed by another set of genes.[2] It lays its eggs in open flesh wounds, typically the wounds of livestock.[8] Pesticides have been designed to interfere with the normal development, killing only larva.[9]