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Botflies, or Dermatobia hominis for humans and the genus Gasterophilus for other mammals, are a bumble bee-like fly that require a human or mammal host in order to complete their life cycle. The life cycle of the botfly is comprised of four stages.
Many people who are itchy experience a crawling sensation and wonder if they have bugs under their skin. While lots of insects like mosquitoes, fleas, spiders, and mites seem to take great delight in biting us, there are very, very few bugs that can actually live under our skin, and even more fortunately, very few of these bugs can be found in North America.
Egg Transmission
Adult female botflies lay their eggs on blood-sucking insects, such as mosquitoes or ticks, that they capture during flight. This practice is known as phoresy. After a period of 10 to 140 days, the host insect consumes a blood meal. This transfers the mature botfly eggs from the flying insect to the warm-blooded animal, which then hatch upon feeling the temperature increase. Adult females can also attach their eggs directly onto the hairs of mammal hosts. Egg hatching and larvae movement may cause the mammal to bite or scratch at the area.
It's a Grub Life
The mammal may consume some of the first instar larvae by licking them. Alternatively, the larvae may travel down hair follicles or through bite wounds and burrow into the mammal's skin. From here, the larvae undergo their final two instars, or molt periods, in the skin of the mammal or in the digestive tract during the winter. Larvae developing in the digestive tract attach to the system's walls and feed on tissue. In early spring, they detach as third instars and are expelled through the mammal's feces. Third instar larvae growing in the skin drop from the mammal host after a period of 30 days.
Rest and Renewal
![Fly Fly](http://s23257.pcdn.co/wp-content/uploads/2016/10/botfly.jpg)
Mature larvae expelled through feces or dropped down from skin in early spring burrow into soil and begin to pupate within two or three days. Pupae do not feed. Instead, they use this time to transform into adults. For a period of one month, the pupae develop adult features, such as wings and antennae. Once fully transformed, sexually mature adult botflies emerge and begin the life cycle over again.
Life Cycle Completion
Like pupae, adult botflies do not feed. Newly emerged from their pupal cases, the adult botflies have sensitive antennae to make up for their poor vision. Male and female adults depend on their sensitive antennae to find each other and mate. During summer and fall, adult females seek hosts for their eggs, whether they catch a fly or mosquito and transfer their eggs to them, or directly attach their eggs to warm-blooded mammals such as cattle, rabbits, sheep and horses.
References (5)
Photo Credits
![Larvae Larvae](http://i1.ytimg.com/vi/MqTZTLI5Kns/hqdefault.jpg)
- Karl Weatherly/Photodisc/Getty Images
Author
Amanda Williams has been writing since 2009 on various writing websites and blogging since 2003. She enjoys writing about health, medicine, education and home and garden topics. Williams earned a Bachelor of Science in biology at East Stroudsburg University in May 2013. Williams is also a certified emergency medical technician.
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Strange sores on a woman's swollen skin weren't caused by an insect bite, but by insects burrowing into her skin, according to a recent report of the woman's case.When the 46-year-old woman went to the emergency room in the United Kingdom with painful marks on her arm, the doctors initially thought she had been. She was given antibiotics and sent home.But when the woman returned the next day because the pain in her arm was getting worse, the doctors realized they were dealing with no ordinary: In the ulcerations on her skin, something was wiggling, according to a recent report of the woman's case. The doctors found several burrowed into her skin, according to the report, published today (March 29) in.The larvae were from the tumbu fly ( Cordylobia anthropophaga), a species found in the tropics of Africa, according to the report. Indeed, the woman had recently returned from a trip to the Ivory Coast, a country in West Africa, the doctors wrote.The tumbu fly is sometimes referred to as the putzi fly or the 'skin maggot,' according to the report. Other fly species are also known to burrow into people's skin, including the human bot fly ( Dermatobia hominis) and the Old World ( Chrysomya bezziana), according to the.Female tumbu flies can lay their eggs on damp clothing or in soil, and if these eggs come into contact with a person's skin, they can burrow in, according to the report.
Typically, larvae are found burrowed into the skin on a person’s back, buttocks or the back of the legs, the doctors said in the case report.The doctors initially tried to squeeze the larvae out of the woman's arm, but ended up having to remove them surgically, said Dr. John Park, a medical resident who treated the woman while working in England in 2016, and is now a Kennedy scholar at the Harvard University T. Chan School of Public Health.The woman was given local anesthesia during the procedure, according to the report.
In some cases, doctors will cover the sores with paraffin wax for the procedure, because this has been shown to help drive the larvae up to, the report said.Once the larvae were removed, the woman's pain disappeared, Park told Live Science. She was surprised to learn that the pain was caused by, Park added.The woman was given antibiotics, and returned for a checkup after a few days, Park said. When he last saw the patient, she was doing well, he said.Park said that if the larvae were not removed, the woman's infection would've gotten worse. The larvae wouldn't have hatched out of her skin as full-grown flies, however.
When the larvae have matured a bit, they work their way out of the skin, drop to the ground and continue to develop in the soil, according to the CDC. This typically occurs at night or early in the morning, so the larvae don't dry out in the sun, the CDC says.Originally published on.
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