Robber flies are fascinating insects known for their predatory prowess and widespread distribution. You might wonder where these intriguing creatures can be found. With approximately 7,000 species recognized worldwide and 1,000 native to North America, these flies have adapted to a variety of environments and can be found in many regions around the globe source.
They inhabit diverse habitats, from tropical and subtropical regions to even the edges of the tundra. Robber flies are versatile creatures, making their homes in forested areas, grasslands, deserts, and other varied landscapes source. In your local ecosystem, you may spot these fascinating hunters perching and scanning for prey. Keep an eye out for them, and remember that their presence indicates a healthy balance in the insect world.
Overview of Robber Flies
Robber flies, belonging to the family Asilidae and order Diptera, are predatory insects known for their voracious appetites and skill in capturing other arthropods as prey. These flies have around 7,000 different species spread across various regions, with over 1,000 species found in North America 1. They are medium-sized to large flies, often with bristly or hairy bodies 2.
In terms of appearance, they have an elongate body with patterned or banded segments, and their adult stages can sometimes mimic the look of wasps and bees 3. Robber flies are quite capable hunters, possessing neurotoxic and proteolytic enzymes that help immobilize and digest their prey 4. Their preferred environments include open habitats, woody edges, and forest glades, where they can bask in the sun and easily spot their next meal 5.
Some common subfamilies in the Asilidae family are Leptogastrinae, Dasypogoninae, Laphriinae, and Asilinae, each with distinct characteristics and behaviors 4. Courtship behavior among robber flies can vary, with some species displaying elaborate rituals to attract mates 4.
Robber flies are often recognized as beneficial insects due to their role in controlling the populations of various other arthropods, such as wasps, bees, dragonflies, grasshoppers, other flies, and some spiders 6. However, they can sometimes prey upon other beneficial insects, making their overall impact on ecosystems a complex one 4.
- Pros of robber flies:
- Help maintain a balance between insect populations
- Reduce the number of harmful pests in various habitats
- Cons of robber flies:
- Can prey on other beneficial insects
- Complex impact on ecosystems
In conclusion, robber flies are fascinating predators that play crucial roles in controlling the populations of other arthropods. Understanding their behavior, habitats, and impact on ecosystems can provide insights into these intriguing assassin flies.
Physical Characteristics
Robber flies have quite a unique appearance that sets them apart from other insects. With approximately 7,000 species spread across the world, their physical traits can vary, but there are some general attributes that you’ll notice. Let’s take a look at some of their key features:
Color: Robber flies come in a range of colors, often blending in with their surroundings. Their hues can range from brown and black to yellow and grey.
Size and abdomen: Their size varies by species, however, they can range from 1/8 of an inch to over 1 inch long. Their abdomen is typically elongated and tapered, giving them a slender appearance.
- Eyes: They possess large, widely-spaced compound eyes, which grant them excellent vision and make them very efficient hunters.
- Bristles and long legs: Robber flies have rows of stout bristles on their body, along with long legs equipped with prominent spikes. These characteristics aid them in capturing and securing their prey.
In summary, here’s a brief comparison of their features:
Feature | Description |
---|---|
Color | Brown, black, yellow, grey |
Eyes | Large, widely-spaced compound eyes |
Size | 1/8 inch to over 1 inch long |
Abdomen | Elongated and tapered |
Bristles | Stout hairs on the body |
Long legs | Equipped with prominent spikes |
Now that you know more about robber flies’ physical characteristics, you can better appreciate these intriguing insects and their unique adaptations.
Distribution and Habitat
Robber flies can be found across the globe, except for Antarctica. They thrive in a variety of habitats such as open grasslands, gardens, and forest glades. In North America alone, there are over 1,000 species of robber flies.
They enjoy sunlit areas, which means you might spot them in your garden or on low plants, where they can find their prey. States like Florida and various islands provide an optimal environment for these predators due to their warm and subtropical climate.
While inhabiting grassy or soil-based surfaces, they keep a lookout for their prey, which consists of other insects. To provide you with an idea of their prevalence, here’s a brief list of places where robber flies are commonly found:
- Gardens
- Open grasslands
- Forest edges
- Low plants
- North America (especially Florida)
Remember, while you may spot robber flies in these locations, they are not out to harm you or be a nuisance. Instead, they play a vital role in controlling insect populations and maintaining a balance within their ecosystem. So, next time you see one in your garden, remember it’s only there to help you by taking care of some unwanted pests.
Prey and Feeding Habits
Robber flies are known for their voracious appetites and their ability to feed on a wide variety of prey. Some of the insects that they commonly consume include:
- Bees
- Grasshoppers
- Other flies
- Wasps
- Ants
- Butterflies
- Flying insects from the Hymenoptera order
- Leafhoppers
- Moths
- Spiders
These predators are skilled at capturing their prey in mid-air. They usually grab them with their specially adapted legs, then deliver a painful bite using their sharp proboscis.
The bite not only immobilizes their victim, but also injects digestive saliva that liquefies the insides of the prey. After that, the robber fly sucks up the liquid appetizing substance.
Robber flies are considered beneficial insects because they help balance insect populations in various habitats by feeding on both pests and other predators. For instance, they can reduce the number of bees and wasps, which are common stinging insects that can threaten your outdoor activities.
In conclusion, robber flies are fascinating insects that play an important role in the ecosystem, controlling the populations of other flying insects. Their effective hunting techniques and adaptive features make them formidable predators. Remember to give these beneficial insects a safe distance when observing them, as their bite can be painful for humans as well.
Life Cycle
Robber flies go through three primary stages: eggs, larvae, and adults. Let’s explore each stage briefly.
Eggs: Female robber flies lay their eggs in various locations, such as decaying wood or soil. This provides a safe environment for the eggs to hatch and develop into larvae.
Larvae: The larval stage is crucial for development. Robber fly larvae are predators, preying upon other insects like white grubs and beetles. They spend most of their time hidden, ambushing small arthropods.
Some key features of robber fly larvae include:
- Predatory nature
- Resemble white grubs
- Live in soil or decaying wood
Adults: Once the larvae pupate, they transform into adult robber flies. As adults, they continue their predatory lifestyle by attacking insects such as dragonflies, bees, and grasshoppers.
Robber flies belong to the family Asilidae, with various subfamilies classified by experts like Oldroyd and Loew. These subfamilies exhibit slight differences in their life cycles and habitats.
In conclusion, the life cycle of robber flies consists of eggs, larvae, and adults, with each stage playing a vital role in their development and survival. They are known for their predatory nature throughout their life cycle, contributing to the balance of insect populations in their habitats. So, while you enjoy the outdoors, remember the role these fascinating insects play in our ecosystems.
Robber Flies and Ecosystem
Robber flies are a family of predatory insects belonging to the Asilidae family. These beneficial insects play an important role in biological control by feeding on a wide variety of arthropods, including wasps, bees, dragonflies, grasshoppers, other flies, and some spiders.
In gardens, they help protect your plants by feeding on pests like beetles (Coleoptera) and aphids, which can harm your foliage. You may come across these insects hovering around apiaries, as they’re bee mimics and often prey on bees.
Their role as biological control agents helps maintain a healthy balance between insect populations in different habitats. For example:
- In gardens, they can reduce the number of pests on your plants.
- In agricultural fields, they can prevent excessive damage to foliage.
- In forests, they can limit the spread of harmful insects.
Robber flies belong to the Diptera order, along with other fly species like Bombyliidae (bee flies) and Syrphidae (hover flies). They share features with other groups of predatory insects like Neuroptera (lacewings) and some species of beetles.
These insects can be considered beneficial due to their predatory behavior during both their adult and larval stages. According to a study, this unique trait makes them key species in controlling insect populations and maintaining community equilibrium.
However, there might be some downsides to their presence, especially for beekeepers. Robber flies could negatively impact apiaries by preying on their bees, which can lead to a decrease in honey production rate. Moreover, an excessive number of robber flies in an area might cause an imbalance in insect populations, leading to a depression in biodiversity.
In conclusion, robber flies are fascinating insects that actively contribute to maintaining healthy ecosystems by controlling insect populations. While they may pose a threat to apiaries, their overall presence is beneficial to various habitats and the wider ecosystem.
Additional Information
Robber flies display a range of colors, including browns, grays, and blacks. As predatory insects, they often target other arthropods like those from the Lepidoptera and Orthoptera orders. For example, they attack wasps, bees, dragonflies, and grasshoppers. They also consume other flies and some spiders, which might help to maintain a healthy balance in insect populations across various habitats. You can learn more about their diet here.
Robber flies belong to the Brachycera suborder of flies. These insects exhibit distinctive features such as:
- Medium to large size
- Bristly or hairy appearance
- Long, tapered abdomen
- Humpbacked appearance
- Spiny legs
As predators, they possess neurotoxic venom to immobilize their prey. It’s important to note that they are also beneficial predators, as they help control pest populations. You can find more information about their anatomy and behavior here.
Comparatively, Neuroptera is a separate order of insects that include lacewings and antlions. Although they share predatory behavior with robber flies, they have distinct differences in physical appearance and preferred habitats.
In conclusion, robber flies showcase various colors and serve as efficient predators, impacting the populations of other arthropods. They do so by targeting a range of insects and using neurotoxic venom to immobilize their prey, making them a fascinating subject of study.
Footnotes
38 Comments. Leave new
Trevor, CSIRO Insects of Australia says there are two groups of giant robber flies in Australia, Phellus and Blepharotes. Both are pictured on the geocities site. Might be worth a look.
Regards,
Grev
Thank you for your kind words, it is an honor that you choose to use some of my photos. I have taken away so much from you and your wonderful website, it just seems right that I give a little something back. Once again, Thank You for all you do.
Hi. I sent a rather blurry picture in last week which looked really similar to this Robber Fly. A friend of mine in West Va took the pic, in a school room. She said her husband saw another one outside in a different town about two days later. I told her to come to this page and check it out — she said yes, this looks like what she saw. Would they be that far North East as West Virginia? Thanks!
As we stated in the original posting, we thought this looked like a Hanging Thief in the genus Diogmites. Chances are that your friend saw a Hanging Thief. Here is a photo from our archives of a Hanging Thief for comparison.
Thanks so much!!! I love this site!
Thanks for your exuberance.
I sent my friend the link to this page, with the Hanging Thief, and she said YES, that was what it was — because the pointy nose was the same 🙂
Hi, thank you for the feedback, this fly was about 50mm long, and we found it in the Isimasilingo Wetland Park, St Lucia, Kwazulu Natal, South Africa at a spot known as Mission Rocks. It was a ver hot and humid but clear day following a recent storm. The insect was sitting on the roof of a small car, hence it was clearly visible, giving me a fantastic opportunity to take some photos.
Regards Stephan
Thank you for following up with a comment on your posting. These first hand observations are a priceless component of our archive.
Hi,
It was in fact found inside the sanctuary dome.
Thanks for the comment. Is the dome the entire ceiling of the sanctuary or is it a special area of the sanctuary?
I got a photo of a Kansas version of the Robber Fly Bumble Bee Mimic last summer.
That looks like a wickedly beautiful Robber Fly!
This is Laphria gibbosa.
Thank you for your input.
I stumbled across one of these sitting in my driveway on the ground. I gave it a very wide birth, its one scary looking bug. I live in greater los angeles CA.
Hi Danny,
The Beelzebul Bee Eater does not range as far west as California. There is one member of the genus found in California, and that is Mallophora fautrix which is much more yellow in coloration. In our opinion, you most likely saw a female Valley Carpenter Bee.
Neoaratus hercules, one of Australia’s largest Asilids. Note the curious structures on his wings, of apparently unknown function.
we’ve spotted one or two (seen on different days) of these devilish bee killers way out of their range here in sacramento, california.
have a blurry photo, but couldn’t get it to post. thank you for your site!
According to BugGuide, the only species of Bee Killer in the genus Mallophora found in California is Mallophora fautrix.
we’ve spotted one or two (seen on different days) of these devilish bee killers way out of their range here in sacramento, california.
have a blurry photo, but couldn’t get it to post. thank you for your site!
Robber Flies are bad boys.
Hi
I found a Giant Blue Robber Fly near my property at Rock Forest NSW 2795 today (Wednesday 8th Feb 2017).
It was dead on the ground where I found it on the road, but I picked it up & brought it home to look it up on google to identify the species.
Hi
I found a Giant Blue Robber Fly near my property at Rock Forest NSW 2795 today (Wednesday 8th Feb 2017).
It was dead on the ground where I found it on the road, but I picked it up & brought it home to look it up on google to identify the species.
I just had one of these on my back porch tonight. Scared me to death. He was buzzing around my porch light. I took 3 pictures. Bandera, texas
Thank you. One of these landed in my mom’s yard (Texas) scared the beejeebees out of her…she took 9 pictures and ran inside.
Just found one in my house in Mossel Bay. Never seen something like it before. Gave it a good whack with a towel ( thought for a moment it was a wasp) I picked it up with toilet paper and just layed there. To my surprise he was playing dead. Loud buzzing sound when it flyes.
Saw one Aug01, 2019 in NW San Antonio. Saw it take off and snatch a huge red wasp in mid-flight!!
That must have been an impressive sight.
Belzebub means lord of the flies in Hebrew. If the flies are going to have a lord, a great big robber fly like this one seems like a good choice.
Today as I was watering my bushes I saw this very same thing pictured here. I am 65 years old and have never seen this before.
Hi. I was comparing this robber fly to other examples of Laphria flava, and they don’t appear to have those bright yellow tibiae. I wonder if it might be something along the lines of Pogonosoma maroccanum instead?
Compare to this one: https://www.inaturalist.org/observations/14230401 or this one: https://www.inaturalist.org/observations/43369675 or this one: https://www.inaturalist.org/observations/3910312
Thanks for posing this possible identification.
Hi. I was comparing this robber fly to other examples of Laphria flava, and they don’t appear to have those bright yellow tibiae. I wonder if it might be something along the lines of Pogonosoma maroccanum instead?
Compare to this one: https://www.inaturalist.org/observations/14230401 or this one: https://www.inaturalist.org/observations/43369675 or this one: https://www.inaturalist.org/observations/3910312
I just found one of these on the front door screen. Only thing is im in San Diego California about a mile from the beach right by sea world. can they be expanding thier territory? How do they kill birds? Is this an invasive species? Dose this mean there is a hive in close proximity?
Thank you.
Miesha Fierro
We believe you probably encountered a different member of the genus native to California, Mallophora fautrix which is pictured on BugGuide.
I just found one of these on the front door screen. Only thing is im in San Diego California about a mile from the beach right by sea world. can they be expanding thier territory? How do they kill birds? Is this an invasive species? Dose this mean there is a hive in close proximity?
Thank you.
Miesha Fierro
I have been privileged to photograph one of these large hairy legged Bees here in Comanche, TX!