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BLOW / BOTTLE FLIES
  Blow fly (Lft) Bottle (Rt)
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COMMON NAME: Blow or bottle flies
SCIENTIFIC NAME: Calliphoraspp., Phaeniciaspp.,
CLASS I ORDER I FAMILY: lnsecta l Diptera / Calliphoridae
METAMORPHOSIS: Complete
INTRODUCTION. This fly’s common name refers to the fly's habit of egg deposition, and comes from antiquity with references dating back into the 16th century. The common name of bottle fly probably comes from the word 'bot" which is an ancient term for the fly maggot, thus bottle would mean a little maggot. These flies are more than just a nuisance, they are of great medical importance because of their mechanical transmission (transfer of disease pathogens directly/mechanically) of disease organisms and ability to cause infestation of tissues in humans and animals. About 75 species occur throughout the United States and Canada.
RECOGNITION. Adults are about 1/8-5/8” long, which makes them about house fly size or slightly larger. Their color is partly or wholly a metallic blue, green, or a dull brassy, sometimes black color. The mouthparts are for sponging up liquid. The antenna have arista which are plumose (feathery) at least for the basal 2/3 of the antenna.
Mature larvae are about 3/8-7/8” long; are eyeless, legless, and taper towards the head from its large rounded rear segment. The color is from pale yellow to white. Posterior spiracles (breathing pores) are flat.
REPRESENTATIVE SPECIES.
1. Black blow fly, Phormia regina (Meigen). Adults are about 1/4-7/16” long; the thorax and abdomen are dark and shiny, the thorax is black with a metallic bluish green luster, the abdomen is metallic yellowish or a bluish green ranging to black. The anterior spiracle has red to orange hair (setae). This fly is found throughout the United States.
2. Bluebottle flies, Calliphora terraenovae Macquart, C. vicina Robineau-Desvoidy, C. vomitoria (Linnaeus), etc. Adult flies are about 1/4-9/16” long; the thorax is dull in color, the abdomen is a shiny metallic blue. This fly is found throughout the United States but is much more common in the northern half of United States and southern Canada.
3. The shiny bluebottle fly, Cynomya cadaverina (Robineau-Desvoidy). The adults are about
3/8-9/16” long; are black with gray markings, the head has gray or yellow to brownish pile (short, fine hairs/setae). The abdomen is a shiny blue-green, the anterior spiracle are dark brown, the lower squama/calypter (posterior basal wing lobes, posterior lobe) are white; the scutellum has 3 pairs of marginal bristles; and the fly is found throughout the United States.
4. Greenbottle flies, e.g., Lucilia illustris (Meigen), Phaenicia (Lucilia for Europeans) sericata (Meigen). Adults about 1/4-3/8" long; the thorax and abdomen are shiny, usually a metallic green, the thorax does not have stripes, the anterior spiracle is blackish, squamae /calypters are white or partly white. The male has concealed abdominal genitalia(P. sericata) or has scattered hairs (L. mustris), the female does not have the abdominal ventral surface appearing variegated (whitish dusted) areas and is found mostly in northern United States and southern Canada.
5. Bronzebottle fly, Phaenicia pallescens (Shannon. The adults are about 3/16-3/8” long with the thorax and abdomen being shiny, usually a metallic bronze; the thorax does not have stripes and the anterior spiracle is blackish.This fly is found in the southern United States
BIOLOGY. The female flies lay their eggs (up to 2,000) on any suitable larval food material. When the eggs hatch, the larvae may feed on the surface and then burrow into the food material, which is less decayed. Larvae pass through 3 instars. Mature larvae usually leave their food material to pupate. Most species pupate within the top 2" of the soil. They usually over-winter as mature larvae or pupae. Many forensice cases have been solved through the knowledge of the length of time the fly develops from egg to pupae and adult fly.
Specific biological notes and developmental times for some of the more common species are as summarized below:
1. Black blow fly (P. regina). The eggs are deposited in glued masses of different numbers. It is known that at an optimal of 990F, eggs hatch in 8.1 hours. The developmental 3 larval instars require 4-15 days. The pupal stage lasts 3-13 days. In the one area in north Texas, the developmental time (egg to adult) requires 10-25 days. With this information, the length of time death occurred can be estimated with amazing accuracy.
2. Bluebottle fly (C. vicina). About 180 eggs are deposited at one time, with a lifetime total of up to 700 eggs. At the range of 25-350F and at 40% RH, fly eggs hatch in about 11 hours. The 3 larval instars require 3-4 days in east Texas, up to 8.75 days in southern Canada, with pupation usually occurring at 7.5 days after the egg is laid. The pupal stage lasts 7-10 days in Texas. In other parts of eastern Texas, developmental time can be up to 20 days.
3. Bronzebottle fly (P. pallescens). Eggs are deposited in groups of about 100 at each location. At an optimal 990F eggs hatch in about 7.7 hours; no hatch below 740F or above 1040F. The 3 instars require about 72 hours under optimal temperatures. The pupal stage lasts 6-7 days in the summer up to weeks in cold weather. Developmental time (egg to adult) can be as short as about 10 days. Can you see how important these flies can be in our forensic search for truth?
4. Greenbottle fly (P. sericata). The females lay about 180 eggs at one time, and have a lifetime total of up to 2,300 eggs. At an optimal 940F, the eggs hatch in a little over 8 hours and have no hatch above 990F. The 1st instar lasts 2-3 hours and does not feed, the 2nd instar requires from 1.5-9.5 days and does feed, and 3rd instar does not feed and is mobile. The pupal stage lasts 3-5 days during the summer and longer in the winter. Adult pre-oviposition (we think) lasts from 5-9 days. Developmental time (egg to adult) may require 10 days or moore.
5. Shiny bluebottle fly (C. cadaverina).The females lay up to 50 eggs at one time. The eggs hatch within the range of 24-72 hours. The 3 instars require from 3-5 days, with the puparium being formed up to 36 days later. The pupal stage lasts from as little as 6-58 days. The developmental time (egg to adult) requires from 19-99 days. Adult pre-oviposition lasts up to 20 days.
Blow fly disease carrying probabilities are many times, overlooked. This is because most species feed on filth such as human, animal excrement and sewage. They have been found to develop in the carcasses of infected animals. These flies in locations such as mentioned, may easily infect the food we eat. Many disease organisms can be mechanically transferred through external body surfaces, from their infected fluids during frequent regurgitation and sponging up of food liquids, and/or by infected fecal deposits. The list of diseases associated with intestinal tract problems is almost identical to that for the common house fly. You might recognize some of the better known which include Entamoeba co/i (Migula) and Shigella dysenteriae (Shiga) which cause diarrhea, and Vibrio comma (Schroeter) which causes cholera. Other non-intestinal disease organisms include the plague (Pasteurella pest/s (Lehmann & Neumann)), anthrax (Bacillus authracis Cohn), tuberculosis (Mycobacterium tuberculosis (Zopf)), and tularemia (Pasteurella tularensis (McCoy & Chapin)).
Myiasis refers to any disease that results from the infestation of tissues or cavities by fly larvae. Infestation by Callitroga americana Cushing & Patton can result in death (8% mortality in 179 cases reported in the early 1930’s). "Surgical maggots" are the larvae of some species which, actually help clean infected wounds and promote healing by consuming bacteria laden fluids on flesh. Intestinal myiasis is usually accidental and has involved species of Chrysomya, Lucilia, Calliphora, and Phaenicia, which cqn occassionally result in diarrhea with bloody discharges and living and/or dead larvae being expelled with the vomit and/or stool. All 8 species listed above have been recorded as causing myiasis in humans.
HABITS. Most species develop in meat or animal carcasses, but if these substrates are not available the flies will use animal excrement, decaying vegetation, and almost any garbage. Dead rabbits, rodents, birds, and other small animals can be the source of flies within structures while dog excrement and garbage are probably the most common outdoor sources.
These flies are usually the first insects to arrive and infest after any animal dies The larvae are used by forensic entomologists to help determine the time of death in murder cases.
A few species are very strong fliers. For example, one study marked and released black blowflies (P. regina)and had 13% trapped between 4-28 miles from the point of release and over 8% at or beyond 10 miles. They are most active on warm, sunny days, and most rest on cool and/or cloudy days. Inside, they are attracted to the bright light coming through windows.
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