Posts Tagged ‘robber flies’

Robber Flies (mating pair)

September 2, 2018

A mating pair of Red-footed Cannibalflies (Promachus rufipes), a species of robber fly (Family Asilidae), was spotted during a photowalk along Deephole Point Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

There’s an obvious difference in the appearance of male and female Red-footed Cannibalflies: the male’s abdomen is “tiger-striped” for its entire length; the female’s abdomen is two-thirds tiger-striped, one-third black. Therefore, the male is shown on the upper-right in the following photo; the female on the lower-left.

23 AUG 2018 | OBNWR | Red-footed Cannibalflies (mating pair)

The next photo shows the male on the upper-left; the female on the lower-right.

23 AUG 2018 | OBNWR | Red-footed Cannibalflies (mating pair)

The last photo shows the female on the left; the male on the right.

23 AUG 2018 | OBNWR | Red-footed Cannibalflies (mating pair)

Copyright © 2018 Walter Sanford. All rights reserved.

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Robber fly (female)

September 17, 2017

An unknown species of robber fly was spotted perching on a wooden post along Deephole Point Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. Notice its abdomen is two-thirds striped and one-third black, indicating this individual is a female.

10 SEP 2017 | Occoquan Bay NWR | robber fly (female)

Copyright © 2017 Walter Sanford. All rights reserved.

Bad day to be a bee!

September 14, 2016

A Red-footed Cannibalfly (Promachus rufipes), a species of robber fly (Family Asilidae), was spotted during a recent photowalk at Huntley Meadows Park. This individual is a female.

Look closely at the full-size version of the following photo.

Did you notice the robber fly is preying upon a bee?

Robber flies feed mainly on other insects. (Whew, that’s a relief!)

The fly attacks its prey by stabbing it with its short, strong proboscis injecting the victim with saliva containing neurotoxic and proteolytic enzymes which very rapidly paralyze the victim and soon digest the insides; the fly then sucks the liquefied material through the proboscis. Source Credit: Asilidae, from Wikipedia.

Copyright © 2016 Walter Sanford. All rights reserved.

Robber Fly eating a Yellowjacket

September 30, 2015

While exploring the “northern wetland” at Huntley Meadows Park, a pair of insects landed on my upper thigh: a female Red-footed Cannibalfly (Promachus rufipes), a species of Robber Fly (Family Asilidae), eating a Yellowjacket (Vespula sp.). The pair was too close to photograph, so I gently “shooed” them away — fortunately they landed on a nearby cattail leaf!

A Red-footed Cannibalfly (Promachus rufipes), a species of robber fly (Family Asilidae), eating a Yellowjacket (Vespula sp.) at Huntley Meadows Park, Fairfax County, Virginia USA.

23 SEP 2015 | Huntley Meadows Park | Robber Fly eating a Yellowjacket

Robber Flies feed mainly on other insects.

The fly attacks its prey by stabbing it with its short, strong proboscis injecting the victim with saliva containing neurotoxic and proteolytic enzymes which very rapidly paralyze the victim and soon digest the insides; the fly then sucks the liquefied material through the proboscis. Source Credit: Asilidae, from Wikipedia.

A Red-footed Cannibalfly (Promachus rufipes), a species of robber fly (Family Asilidae), eating a Yellowjacket (Vespula sp.) at Huntley Meadows Park, Fairfax County, Virginia USA.

23 SEP 2015 | Huntley Meadows Park | Robber Fly eating a Yellowjacket

Thanks to BugGuide Facebook group members James W. Beck for verifying my identification of the Robber Fly, and to Ian Kho for definitely identifying the genus of Yellowjacket and tentatively identifying its species.

[The] Yellowjacket is in the genus Vespula. Mostly yellow face suggests V. maculifrons/flavopilosa. Source Credit: Ian Kho.

Copyright © 2015 Walter Sanford. All rights reserved.

Red-footed Cannibalflies (mating pairs)

January 5, 2015

The following photographs show mating pairs of Red-footed Cannibalflies (Promachus rufipes) spotted on 06 October 2014 near a vernal pool in the forest at Huntley Meadows Park. Red-footed Cannibalfly is a species of robber fly seen commonly at the park.

It never occurred to me that male and female robber flies might look different — I just assumed they look the same. Well, you know what they say about that kind of thinking. As it turns out, there is an obvious difference in appearance that I didn’t notice until I examined the photos of these mating pairs. By coincidence, the male is shown on the left and the female on the right in every photo. Do you see what I saw?

Red-footed Cannibalflies (mating pair)

The male’s abdomen is “tiger-striped” for its entire length; the female’s abdomen is two-thirds tiger-striped, one-third black.

Red-footed Cannibalflies (mating pair)

I never noticed the difference in appearance between males and females until I edited these photos. When I took a second-look at other photos of Red-footed Cannibalflies posted on my blog, it was easy to identify the gender of the specimens. Who knew?

Red-footed Cannibalflies (mating pair)

Copyright © 2015 Walter Sanford. All rights reserved.

Huntley insects endorse Coleman camp stool

November 8, 2014

In addition to my photography gear, I usually carry a Coleman camp stool when I go photowalking at Huntley Meadows Park. I am the self-described (and self-appointed) “Chair-man of the Boardwalk.”

The small, lightweight folding chair is good for resting while waiting for “the game to come to me.” The camp stool also enables me to get closer to subjects either on- or near the ground. And I think it’s easier to hold my camera rock-steady when I’m sitting on the chair with my elbows resting on my knees.

I like my Coleman camp stool. Several of my favorite insects at the park like to rest on the camp stool too!

Autumn Meadowhawk dragonfly (male) | 26 September 2014

Autumn Meadowhawk dragonfly (male) | 20 October 2014

Blue-faced Meadowhawk dragonfly (male) | 09 October 2014

Blue-faced Meadowhawk dragonfly (male, perching on Coleman camp stool)

Red-footed Cannibalfly (female) | 02 October 2014

Copyright © 2014 Walter Sanford. All rights reserved.

The real monsters of Huntley Meadows

September 19, 2014

Longtime residents of eastern Fairfax County, Virginia USA may recall reading about the “Mount Vernon Monster” that reportedly roamed the region during the late 1970s. Although I have neither seen nor heard the monster, I jokingly reply “Bigfoot” whenever people pass me at Huntley Meadows Park and ask whether I shot any good photographs. But seriously, folks — there are real monsters at the park, including horse flies and robber flies.

The following photos show two horse flies, possibly Tabanus calens, spotted during recent photowalks along the boardwalk in the central wetland area. Both individuals are females. Male horse flies don’t bite; females bite, painfully!

Adult horse flies feed on nectar and sometimes pollen. Females of most species are anautogenous, meaning they require a blood meal before they are able to reproduce effectively, if at all. Much like male mosquitoes, male Tabanidae are not ectoparasitic and lack the mouth parts (mandibles) that the females use in drawing the blood on which they feed. Most female horse flies feed on mammalian blood, but some species are known to feed on birds or reptiles. Some are said to attack amphibians as well. Source Credit: Horse-fly, from Wikipedia.

Horse fly (female)

17 September 2014. Photo 1. Horse fly (female).

Males have eyes that meet along a seam down the middle of the head (holoptic eyes); females have eyes that are well-separated. Source Credit: Benjamin A. Coulter, member of the BugGuide group on Facebook.

Horse fly (female)

17 September 2014. Photo 2. Horse fly (female).

The next gallery shows another female horse fly spotted along the boardwalk on 15 September 2014.

The last photo shows a Red-footed Cannibalfly (Promachus rufipes), a species of robber fly spotted near the beginning of the boardwalk.

Red-footed Cannibalfly (Promachus rufipes)

10 September 2014. Red-footed Cannibalfly (female).

Robber flies feed mainly on other insects. (Whew, that’s a relief!)

The fly attacks its prey by stabbing it with its short, strong proboscis injecting the victim with saliva containing neurotoxic and proteolytic enzymes which very rapidly paralyze the victim and soon digest the insides; the fly then sucks the liquefied material through the proboscis. Source Credit: Asilidae, from Wikipedia.

There are “approximately 1,040 species of robber flies in approximately 100 genera in our area.” Source Credit: Family Asilidae – Robber Flies, from BugGuide. Thanks to Mike Powell, fellow wildlife photographer and blogger, for identifying the species of robber fly shown above!

Copyright © 2014 Walter Sanford. All rights reserved.

Bumble Bee-like Robber Fly

August 4, 2014

Robber Fly (Laphria macquarti)

The preceding photograph shows a Bumble Bee-like Robber Fly (Laphria grossa) perching near a vernal pool at Huntley Meadows Park on 22 July 2014.

I think the Bumble Bee-like Robber Fly looks like a lost member of ZZ Top! More conventional thinkers see them differently.

A mimic of a Bombus (Psithyrus). Source Credit: Species Laphria grossa, BugGuide.

Copyright © 2014 Walter Sanford. All rights reserved.

Robber Fly

March 10, 2014

Robber Fly (Family Asilidae)

The preceding photograph shows a Robber Fly (Family Asilidae) spotted on 14 August 2013 during a photowalk along the boardwalk in the hemi-marsh at Huntley Meadows Park.

Thanks to Kim Phillips, Small Wonders, for verifying my tentative field identification!

Editor’s Note: This specimen is probably a Red-footed Cannibalfly (Promachus rufipes), a species of robber fly seen commonly at Huntley Meadows. This individual is a male.

Copyright © 2014 Walter Sanford. All rights reserved.


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