Stomoxys is a genus of flies belonging to the family Muscidae, commonly known as stable flies. These flies are widely distributed across different regions of the world and are of significant economic and veterinary importance. The genus includes several species, with Stomoxys calcitrans being the most common and well-known species encountered.
1. Stomoxys
Introduction
Stomoxys is a genus of flies belonging to the family Muscidae, commonly known as stable
flies. These flies are widely distributed across different regions of the world and are of
significant economic and veterinary importance. The genus includes several species, with
Stomoxys calcitrans being the most common and well-known species encountered.
Stable flies are known for their piercing-sucking mouthparts, which they use to feed on the
blood of various hosts, including livestock, wildlife, and humans. Unlike house flies, stable
flies are not just nuisance pests but can also cause significant discomfort and economic
losses in agricultural and livestock industries.
These flies have a distinctive appearance, with their gray or dark-colored bodies and
checkerboard-like pattern on their abdomen. They are similar in size to house flies,
measuring around 6-8 millimeters in length. One of the key distinguishing features of stable
flies is the presence of a bayonet-like proboscis, which they use to puncture the skin of their
hosts for blood feeding.
Life cycle
Life Cycle: Stable flies undergo a complete metamorphosis, consisting of four stages:
egg, larva, pupa, and adult.
Eggs: Female stable flies deposit their eggs in decaying organic matter or moist
areas associated with manure, hay, or silage. Each female can lay up to 500 eggs
during her lifespan.
Larvae: The larvae hatch from the eggs and feed on decaying organic material, such
as rotting vegetation and manure. The larval stage lasts for about 10-21 days.
Pupae: After the larval stage, the larvae develop into pupae. Pupae are non-feeding
and undergo significant morphological changes within a pupal case. This stage
typically lasts for 7-14 days.
Adults: Adult stable flies emerge from the pupae and seek hosts for blood meals.
They primarily feed on the blood of livestock, wildlife, and humans. Adult stable flies
have a lifespan of around 2-4 weeks.
Habits
Stable flies are primarily found in agricultural areas and locations where livestock or
wildlife are present. They are active during the day and are commonly found around
livestock facilities, stables, barns, and open fields. Stable flies prefer warm
temperatures and are often found in clusters.
2. Pathogenesis
Stable flies are considered mechanical vectors of various pathogens, including
bacteria, viruses, and parasites. They can mechanically transmit these pathogens by
picking them up from contaminated sources and subsequently depositing them on
the skin of animals or humans while taking a blood meal. Some of the diseases
associated with stable flies include anthrax, bovine leukosis, and equine infectious
anemia.
Regarding mechanical transmission, stable flies can act as vectors for various
pathogens, including bacteria, viruses, and parasites. Some of the diseases that can
be mechanically transmitted by stable flies include:
Bacteria:
Anthrax (caused by Bacillus anthracis)
Bovine tuberculosis (caused by Mycobacterium bovis)
Campylobacteriosis (caused by Campylobacter spp.)
Viruses:
Equine infectious anemia (caused by Equine infectious anemia virus)
Vesicular stomatitis (caused by Vesicular stomatitis virus)
Parasites:
Trypanosomiasis (caused by Trypanosoma spp.)
Onchocerciasis (river blindness) (caused by Onchocerca spp.)
o It's important to note that while stable flies can mechanically transmit these
pathogens, they are not the primary vectors for most of these diseases.
Transmission typically occurs when stable flies feed on an infected host and
then subsequently feed on another susceptible host, depositing the
pathogens on the skin.
Clinical signs and symptoms
Clinical signs and symptoms of stable fly infestation on animals can vary depending
on the severity of the infestation and the species of animals affected. Here are some
common clinical signs observed in animals affected by stable flies:
3. Irritation and Restlessness: Animals may display signs of irritation,
restlessness, and discomfort due to stable fly bites. They may continuously
swish their tails, kick, or stamp their feet to ward off the flies.
Agitation and Nervousness: Infested animals may exhibit signs of agitation
and nervousness, often accompanied by increased movement or pacing.
Decreased Feed Intake: Stable flies can cause reduced feed intake in animals
due to the constant annoyance and discomfort caused by their bites. This can
lead to decreased weight gain and overall decreased productivity.
Weight Loss and Poor Growth: Prolonged infestations of stable flies can result
in weight loss and poor growth in young animals.
Skin Lesions: Persistent biting by stable flies can lead to the development of
skin lesions. These lesions can vary from small, raised bumps to larger, open
sores or ulcers. The affected areas may be painful, itchy, or irritated.
Secondary Bacterial Infections: The open sores or lesions caused by stable
flies can become vulnerable to secondary bacterial infections. These
infections can further complicate the condition and prolong the healing
process.
Anemia: In severe cases of stable fly infestations, especially in young
animals, repeated blood loss through feeding can lead to anemia, resulting in
weakness and lethargy.
Treatment and Control
To control stable flies, an integrated pest management (IPM) approach is
recommended. Some measures that can be taken include:
Sanitation: Proper waste management and removal of decaying organic matter can
help reduce breeding sites for stable flies.
Habitat modification: Eliminate or reduce moist areas, standing water, and decaying
vegetation where stable flies breed.
Insecticides: Use approved insecticides for treating animals, premises, or specific
breeding areas as per local regulations and guidelines.
4. Fly traps and baits: Various types of fly traps and baits can be employed to reduce
stable fly populations in specific areas.
Biological control: Introduce natural predators, such as parasitic wasps or
nematodes, that can target stable fly larvae.
Personal protection: Use protective measures like fly repellents, physical barriers
(e.g., fly sheets) for animals, and screens for windows or doors.
It's important to note that specific treatment and control measures may vary depending on
the region, local regulations, and the target animal species.
References:
1. Byford, R. L., Craig, M. E., Crosby, B. L., & Toscano, M. J. (1992). Biology and
control of stable flies. In Annual review of entomology (Vol. 37, No. 1, pp. 147-176).
2. Campbell, J. B., & Berry, I. L. (2004). A guide to managing pests in livestock and
poultry (Vol. 3). Purdue University Cooperative Extension Service.
3. Geden, C. J. (2012). Control of stable flies in livestock operations. University of
Florida, IFAS Extension.
4. Kaufman, P. E., & Butler, J. F. (2007). Stable flies (Diptera: Muscidae) and their
management on livestock operations. Entomology Today, 13(6), 285-296.