A Green Bottle fly, Chrysomya spp. upfront
A Green Bottle fly, Chrysomya spp. resting on a leaf surface
A Green Bottle fly flying and landing on leaves
A Green Bottle fly covered with fungal spores it got from an infested leaf
The uncollected, exposed garbage bag on the street attracted the influx of bottle flies
It was during a spot visit in a warehouse facility at the heart of the Al Quoz Industrial Area that I noticed numerous green bottle flies passing and buzzing by. Following the flight pattern of the flies, I was led to a large bag of uncollected, exposed and stinky garbage. The horde of shiny, metallic green bottle flies were landing and flying unto the garbage bag and on the leaves of an adjacent plant.
Adult green bottle flies are metallic green in color, they bear NO stripes in their backs, with thick setae on the meron (posterior part of the proximal rim of the coxa) and a plumose (with long hair) arista. They have a pair of large red eyes and transparent, veined-wings. Adults are 10-12mm long. Adults feed on decaying matter, manure, plant sap and flowers.
The larvae (maggots) are white to yellowish in color, elongated, tapering and can reach up to 14mm. Brought about by their voracious feeding on the carcass, each maggot undertake 3 larval instar before it pupates.
Species Diversity of Chrysomya and Distribution
There are 12 species of Chrysomya reported worldwide. In the United Arab Emirates, 3 species have been reported to be present: C. albiceps, C. bezziana and C. regalis. The Old World, Screw Worm fly, C. bezziana is considered the most important myiasis associated filth fly in the tropical regions of Africa, Asia, Indo-Pacific Islands and in the Middle East.
Biodynamic Notes
The eggs are 1mm long, white to yellowish in color. Females lay can lay an egg mass of 50-200 eggs. In come cases, the females engage in group egg oviposition which produces larges egg masses (appearing like rice balls) on animal carcasses.
Upon hatching from its egg mass it immediately feeds on the flesh of the dead animal until it reaches the third instar stage and then it leaves the carcass and pupates.
TOTAL DEVELOPMENT PERIOD from egg to adult can reach up to 2 weeks depending on the food and temperature.
Upon emergence as adult flies the females can begin to oviposit eggs after 5 days. Total adult lifespan can reach up to 6 weeks.
Due to the association with animal carcass, manure and other filthy conditions, green bottle flies are considered MEDICALLY IMPORTANT filth flies as they can carry and transmit numerous pathogens that cause diarrhea, dysentery and other gastro-intestinal diseases and also MYIASIS (= infection of a fly maggot on human tissue).
A notable species, C. bezziana unlike the other species does not breed on carrion or excrement but is totally dependent upon living tissues for its development. The maggots attack various parts of the body but it prefers infesting the eyes, nasal cavities and head wounds (talk about the right spots)!
The presence of Chrysomya species are of primary importance in the medico-criminal forensic entomology. Due to the well studied and documented duration of each development stage, the stage present can determine timings of death of victims.
If there is a prevalence of bottle flies flying and buzzing indoors, this can be a sign that there is a dead bird or rat inside the premises.
IPM RECOMMENDATIONS
1. Inspection. Inspection. Inspection. Conduct detailed inspection of the area to determine filth flies entry points, breeding, feeding areas and other structural factors favoring their presence.
2. Larval breeding sites removal. Keep area clean and dispose garbage properly (especially animal waste and decaying organic materials).
3. Exclusion procedures. Proper door management, repair and secure all window and door screens.
4. Insect Light Traps. Strategic installation of insect light traps indoors to capture the flying intruders.
5. Outdoor Fly Bottle Traps. Strategic installation of fly bottle traps on applicable areas outdoors to minimize numbers (just be cautious on your bottle trap placement points as the contents of the fly bottle traps will get stinky).
6. Targeted chemical treatments. Application of residual insecticide or chemical fly bait formulations on appropriate fly resting sites. (READ, UNDERSTAND and FOLLOW the PESTICIDE LABEL always).
Bottle flies are included in the dreaded group of large filth flies (house flies, blow flies, flesh flies), wherein their population development is highly influenced by the factors human activity creates! Meaning, more filth from humans means more favorable factors available for filth flies!
Awesome creatures! Awesome CREATOR!
Thanks for your support and careful attention.
If you need Pest Management Training, Technical Field Support, On-Line and On-Site Consultancy, please feel free to send me an email: odelon.reyes@gmail.com
