A vibrant red-eyed tree frog perched on a leaf in Belize, symbolizing the rich biodiversity of the rainforest, where the author's botfly adventure began.
My adventure, in retrospect, likely commenced with capturing this very photograph amidst the lush landscapes of Belize. For five days, I diligently shielded myself, applying insect repellent with unwavering dedication. However, on the final day, my vigilance faltered. I was in Belize, leading a macrophotography workshop at Bugshot, and as the course neared its end, I relaxed, seeking to photograph red-eyed tree frogs in the rainforest surrounding our lodge. I rolled up my sleeves, but in a moment of misplaced repellent and sheer laziness, I skipped the DEET. A critical error. As I focused on the frogs, swarms of mosquitoes, as if sensing an unprotected feast, descended upon my arms and face. Yet, it being my last day, I ignored the relentless biting and continued photographing. Later, my arms were itchy, a familiar annoyance, nothing truly alarming.
Close-up view of a human botfly larva's breathing tube protruding from the skin, highlighting the initial discovery of the infestation.
Back home, things took an unexpected turn. Some mosquito bites persisted in itching, growing larger instead of fading. It didn’t take long to dawn on me: I had unwittingly brought back more than just memories from Belize. Embedded within my skin were larvae of the Human bot fly (Dermatobia hominis). This wasn’t my first encounter with these parasites, but the sheer number was unprecedented – at least six larvae were thriving on my arms, four clustered closely on my right forearm. Ultimately, only three survived the first week. One particularly active and painful larva resided on my elbow, a nuisance that had to be removed. Yet, I decided to keep the remaining two. Strange as it may seem, I felt a reluctance to eliminate them, driven by a unique opportunity to witness an adult bot fly emerge, something I had never seen.
Human bot flies are notorious among entomologists and inhabitants of tropical regions in Central and South America. Many biologists working there have, at some point, hosted a torsalo, often in inconvenient locations like eyelids, lips, or scalps. Removal methods vary, often involving suffocating the larva with substances like glycerine jelly, raw steak, or duct tape, followed by extraction. While generally effective, these methods carry a risk of leaving parts of the larva behind, potentially leading to infection. For previous removals, I preferred a suction venom extractor, which widens the warble (the wound) and gently pulls the larva out intact and alive. I discovered this method, documented in Boggild et al. 2002 (Clin. Infect. Dis. 35: 336-8), after a doctor suggested surgical removal. I declined, opting for self-research into furuncular myasis.
Detailed view of a mature human botfly larva's armored body and mandibles, emphasizing its impressive yet relatively harmless nature as a skin parasite.
Despite their name, Human bot flies (D. hominis) aren’t exclusive to humans. They readily infest other primates, ungulates, and large mammals. Similarly, other bot fly species (Oesteridae), typically targeting smaller mammals, may occasionally infest humans. However, D. hominis infections in humans are more frequent due to their unique egg-laying strategy. Unlike other bot flies that lay eggs near host burrows, D. hominis females capture and oviposit on other exoparasites like mosquitoes, ticks, and deer flies. The eggs hatch on these intermediate hosts and transfer to a definitive host, often human, upon sensing body heat. Larvae may enter through the mosquito bite or hair follicles. Even newly hatched larvae are equipped with upward-pointing spines, making manual removal challenging.
The puparium of a human botfly, showcasing anterior spiracles for breathing during pupation, and color change from light brown to dark as it matures underground.
Inside the skin, the larva undergoes three molts, growing from sugar-grain size to peanut size in 7-10 weeks. The warble expands, sometimes bleeds, but generally remains painless unless nerve endings are disturbed. Infections are rare, possibly due to larval antibiotic secretions. Fully grown, the larva exits, burrows into the ground, and pupates. The wound usually heals within days. Overall, not a severe issue. However, some people understandably dislike hosting a squishy creature in their skin.
A mature human botfly in the rainforest, highlighting its role as a component of the rainforest ecosystem alongside monkeys and butterflies.
Emerging research suggests parasites often manipulate host behavior. Horsehair worms induce terrestrial grasshoppers to jump into water, where the worm emerges. Parasitoid wasps are protected by their brainwashed caterpillar hosts. Humans are also susceptible to parasitic manipulation. Toxoplasmosis, caused by Toxoplasma gondii, may reduce intelligence and increase risk-taking in men, potentially increasing chances of becoming prey for large cats, Toxoplasma‘s definitive host. Interestingly, women show a statistically significant increase in intelligence.
After deciding to raise my botflies, I wondered: have entomologists, by tolerating botflies as a rite of passage, inadvertently selected for botfly strains that manipulate human behavior to ensure their survival? Or do I simply have toxoplasmosis?
A newly emerged human botfly, showing traces of the ptilinum, a temporary structure used for breaking free from the puparium.
Regardless, the flies thrived for nearly 10 weeks, emerged, pupated, and briefly lived as adults. Adult bot flies lack functional mouthparts, cannot feed, and live only a few days. They are surprisingly beautiful, undergoing a remarkable transformation from larva to adult.
This was an intriguing experience, and I’m glad I saw these insects through maturity. But rest assured, DEET will be my constant companion in Belize henceforth.
Stay tuned for a video showcasing the botfly development!
Update: The video is now available.
A composite image showing the human botfly life cycle stages, emphasizing the dramatic size difference between larval instars.
Postscript I nurtured my botflies, ensuring their survival post-Belize. Will this redeem me after the puppy-sized spider incident? Probably not. Do I care? Guess. And for the record, I didn’t kill that spider; another scientist collected it – a detail lost in online media frenzy. Clarification was pointless, irrelevant to scientific collecting – I’ve collected specimens, and defend biologists doing the same.
Postscript 2 Gil Wizen documented his botfly-raising experience on his blog.
Do Flies Live in the Rainforest? Exploring Rainforest Insects and the Botfly Example
Yes, flies most certainly live in the rainforest. In fact, rainforests, with their warm, humid climates and abundant vegetation, are hotspots for insect biodiversity, including a vast array of fly species. While the question “Do Flies Live In The Rainforest?” might seem simple, the reality is a complex and fascinating world of ecological interactions and adaptations. This article delves into the world of rainforest flies, using the intriguing case of the human botfly to illustrate the unique insect life thriving in these environments.
My Botfly Encounter: A Rainforest Souvenir
My personal encounter with rainforest flies took an unexpected turn during a macrophotography trip to Belize. Like many venturing into tropical rainforests, I was aware of mosquitoes and other biting insects. However, I was less prepared for a more insidious rainforest inhabitant: the human botfly.
The story began innocently enough, photographing red-eyed tree frogs. A lapse in applying insect repellent led to numerous mosquito bites. Unbeknownst to me, some of these bites were more than just mosquito bites. They were the entry points for botfly larvae, hitchhiking a ride back home with me.
The Human Botfly: A Rainforest Fly with a Unique Lifestyle
The human botfly (Dermatobia hominis) is a remarkable example of a rainforest fly with a highly specialized parasitic lifestyle. Answering “do flies live in the rainforest?” with the botfly example highlights the incredible diversity and often surprising nature of rainforest insects.
These flies are not just any flies; they are obligate parasites, meaning their larvae must develop inside a living host to survive. And while “human” botfly suggests humans are their primary target, they infest a range of warm-blooded mammals in Central and South American rainforests.
Their life cycle is as fascinating as it is somewhat unsettling. Female botflies employ a clever strategy called phoresy. They don’t lay eggs directly on a host. Instead, they capture mosquitoes, ticks, or other biting flies, and glue their eggs onto them. When these carrier insects land on a warm-blooded host, the botfly larvae hatch in response to body heat and quickly burrow into the skin.
Botflies and the Rainforest Ecosystem
While the thought of botflies might be unpleasant, they are a natural part of the rainforest ecosystem. They represent just one facet of the incredible insect diversity found in these habitats. Rainforests are teeming with flies of all kinds, playing various ecological roles:
- Pollinators: Many rainforest flies are important pollinators, visiting flowers and transferring pollen, contributing to plant reproduction.
- Decomposers: Flies, particularly their larvae (maggots), are crucial decomposers, breaking down organic matter and recycling nutrients within the rainforest.
- Predators and Prey: Flies serve as both predators and prey within the rainforest food web. They prey on other insects and are preyed upon by birds, reptiles, amphibians, and other insects.
- Parasites: As exemplified by botflies, some rainforest flies have evolved parasitic lifestyles, influencing the health and behavior of their hosts and contributing to the complex dynamics of the ecosystem.
Beyond Botflies: A World of Rainforest Flies
Answering “do flies live in the rainforest?” opens the door to exploring countless other fly species. Rainforests are home to:
- Fruit flies: Exploiting the abundance of fruit, rainforest fruit flies are incredibly diverse and play roles in decomposition and nutrient cycling.
- Fungus gnats: Thriving in the humid understory, fungus gnats are abundant in rainforests and contribute to fungal decomposition.
- Soldier flies: Often brightly colored, soldier flies are found in rainforests and their larvae can be aquatic or terrestrial, contributing to various ecosystem processes.
- Crane flies: These large, delicate flies are common in rainforests, particularly in damp areas, and their larvae often live in soil or decaying vegetation.
Conclusion: Rainforests – A Fly Paradise
Do flies live in the rainforest? Absolutely. Rainforests are vibrant ecosystems teeming with life, and flies are a significant and diverse component of this insect world. From the specialized parasitic lifestyle of botflies to the countless other fly species fulfilling essential ecological roles, these insects are integral to the health and functioning of rainforest ecosystems. My personal encounter with botflies provided a close-up, albeit somewhat unwelcome, glimpse into this fascinating aspect of rainforest biodiversity, reinforcing the vital role insects play in these critical habitats.
References
- Boggild, A. K., et al. (2002). Furuncular myiasis: a simple and effective method for extraction of Dermatobia hominis larvae. Clinical Infectious Diseases, 35(3), 336-338.
