Blowfly

Introduction

The common name of blowfly refers to the fly's deposition of eggs, and comes from antiquity with references dating back into the 16th century. The common name of bottle probably comes from "bot" which is an old term for maggot; thus, bottle would mean a little maggot. These flies are more than just a nuisance, they are of medical importance because of their mechanical transmission of disease organisms and ability to cause myiasis in humans and animals. About 80 species occur throughout the United Stated and Canada.

Recognition

Adults are about 1/8 to 5/8 inch long, about house fly size or slightly larger. Color partly or wholly metallic blue, green or dull brassy sometimes black. Mouthparts sponging. Antenna with arista plumose at least on basal two-thirds. Thorax with postscutum not developed; usually with two notopleural bristles; hindmost posthumeral bristle located lateral to presutural bristle; hypopleuron with bristles. Wing with fourth vein strongly angled forward, cell R5 narrowed but rarely closed distally.

Mature larvae are about 3/8-7/8 inch long; eyeless, legless, and tapering towards head from large rounded rear segment, head represented by one pair of dark hooks. Color spiracular openings consisting of three straight, subparallel slits aligned diagonally, which are completely surrounded by an oval black ridge that has a dark donut-shaped structure attached to its inner margin, spiracular plated surrounded by 10 or more tubercles.

Habits

Most species develop in meat or animal carcasses, but if these are not available they will use animal excrement, decaying vegetation, and/or garbage. Dead rodents, birds, and other small animals can be the source of flies within structures while dog excrement and garbage are common outdoor sources.

These flies usually are the first insects to arrive and infest after an animal dies. Their larvae often are used by forensic entomologist to help determine the time of death in murder cases.