Blue Blowfly

Appearance

"C. vicina" is known as a blue bottle fly because of the metallic blue-gray coloration of its thorax and abdomen. It is distinguished from the commonly known "C. vomitoria" by its bright orange cheeks. The blue bottle fly is approximately 10-11 mm in length. The sclerites at the base of the coxa are yellow or orange. By chaetotaxy, the study of bristle arrangement, Calliphorids are characterized by having black bristles on the meron and two to three bristles on the notopleuron.

The similarities between the different species of Calliphora can make identification of immature stages nearly impossible. From the first instar to the pupa stage "C. vicina" is identical to that of "C. vomitoria".

Distribution

"C. vicina" are found throughout the U.S. in urban areas and are most abundant in early spring and fall where the temperatures are around 55-75˚F....hieroglyph snipped... The species predominates in Europe and the New World, but has found its way into other countries via harbors and airports. It was first recorded in South Africa in 1965 when a specimen was collected near Johannesburg, but specimen collections have been few and sporadic since then.

Behavior

"C. vicina" play an integral part in post mortem interval determination. Factors such as region, weather temperatures, time of day and conditions under which the body was found all contribute to determining a post mortem interval. To complete the calculation the entomologist must consider what is commonly known about "C. vicina" and integrate it with experimental data gathered from a crime scene. The entomologist must know how the blow-fly behaves specifically in the area where the body was discovered. This involves recording environment temperatures at the crime scene as well as retrieving a history of the climate in the region. "C. vicina" in particular is adapted to cooler temperatures, appearing most commonly in winter and less often in the summer months. This puts their flight activity threshold at above 55-60° F, a lower temperature than most other blow-flies. Knowing the threshold temperature allows the entomologist to calculate accumulated degree days, which in turn helps determine PMI.

Some knowledge regarding "C. vicina" behavior is well known. Case studies have shown that it is not the first species in arrival. However, it does appear one to two days before "Phaenicia sericata". However, determining PMI is an intricate process because there is still much that we do not know about "C. vicina" behavior. For instance, it is a long held belief that the species is not nocturnally active. Recently, however, it has been shown that "C. vicina" is indeed active at night under certain experimental conditions.