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The act of prey acquisition

The act of prey acquisition
Photo Information
Copyright: Gerhard Theron (gerhardt) Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1936 W: 244 N: 4106] (11620)
Genre: Animals
Medium: Color
Date Taken: 2005-05-13
Categories: Insects
Camera: Canon EOS 300D, Canon EF 100-400mm F/4.5-5.6L IS USM, Digital ISO 200, Kenko Extension tube (36mm)
Exposure: f/10.0, 1/100 seconds
Details: (Fill) Flash: Yes
More Photo Info: [view]
Photo Version: Original Version
Date Submitted: 2005-05-19 14:13
Viewed: 4208
Points: 48
[Note Guidelines] Photographer's Note
Robber Fly
Unknown species

The robber flies are an abundant and diverse family within the order Diptera that are known for their predatory behaviour. Asilidae diversity can be attributed to their broad distribution. As their common name implies, robber flies have voracious appetites and feed on a vast array of other arthropods. Asilidae adults attack wasps, bees, dragonflies, grasshoppers, other flies, and some spiders.

Asilidae are a family of true flies Diptera. To date, there are approximately 6,750 described species of Asilidae distributed throughout the world. There are nearly 500 South African species of robber flies. All robber flies have a characteristic divot on top of the head, which is located between their especially prominent compound eyes. In general, adult Asilidae have an elongate body with a tapered abdomen. However, some species are stout and hairy, mimicking bumble bees, and still others may be slender and have a damsel fly appearance. Adults range in size from small (3 mm) to very large (over 50 mm), averaging 9 to 15 mm in length. Robber flies have long, strong legs that are bristled to aid in prey capture. Sexual dimorphisms are not extreme, although females tend to have slightly broader abdomens than males. Most robber flies have a brown, grey, or black coloration.

Robber flies exhibit minimal courtship behaviour. Instead, the male pounces on the female much like an act of prey acquisition. (…like most men I presume) :)Female Asilidae deposit whitish-colored eggs on low-lying plants and grasses, or in crevices within soil, bark, or wood. Egg-laying habits depend on the species and their specific habitat; most species lay their eggs in masses, which are then covered with a chalky protective coating. Robber fly larvae live in the soil or in various other decaying organic materials that occur in their environment. Larvae are also predacious, feeding on eggs, larvae, or other soft-bodied insects. Robber flies overwinter as larvae and pupate in the soil. Complete development ranges from one to three years, depending on species and environmental conditions.

Robber flies are opportunistic predators, their diets often reflecting prey availability in a particular habitat. Robber flies generally establish a perching zone in which to locate potential prey. Perching height varies by species, but generally occurs in open, sunny locations. Asilidae seize their prey in flight and inject their victims with saliva containing neurotoxic and proteolytic enzymes. This injection, inflicted by their modified mouthparts, rapidly immobilizes prey and digests bodily contents. The robber fly soon has access to a liquid meal, which is generally consumed upon returning to a perched position.

I try to ID most of my posts but this species evaded me. We have nearly 80 genera of Hoverflies in SA and no books. The one I have covers about 20 genera. Hope you like it.

Toni, liquidsunshine, carper, Runnerduck, ellis49, AndyB, Esox, elroyie, PDP, Callie, naki, christophe, Fisher, red45, Comandante, TAZ, dew77, puffy has marked this note useful
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ThreadThread Starter Messages Updated
To ellis49: Great to be back...gerhardt 1 05-19 16:56
To Toni: Sorry...gerhardt 1 05-19 14:24
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Critiques [Translate]

  • Toni Gold Star Critiquer/Gold Note Writer [C: 403 W: 2 N: 316] (2034)
  • [2005-05-19 14:22]
  • [+]

Great shot. Fantastic details in the right places. Nice POV. Thanks for adjusting the text.
Regards Toni

Good shot Gerhard,
Well composed, good sharp detail and colours.
Excellent exposure. The notes are great. Thanks for posting.

An incredibly sharp image, great pov and composition.
A very informative note too.
Thanks for posting.

Great macro, Gerhard.
Nice to see a post from you again.
Very well composed, great details and good POV. Great note too.
Excellent work, my friend.

  • Great 
  • AndyB Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 1366 W: 32 N: 1351] (3982)
  • [2005-05-19 14:43]

Excellent capture Gerhard,
Nice and sharp,good effective diagonal composition.
As always a very informative and interesting note too.
Great work,well done.

Very good capture, very good sharpness, and great action picture, I think that you did a little bit over sharpen to the picture.

  • Great 
  • PDP Gold Star Critiquer/Gold Star Workshop Editor [C: 2821 W: 344 N: 3779] (11769)
  • [2005-05-19 15:32]

Gruesome and captivating. Excellent capture Gerhard. The details are terrific and very nice use of DOF. Great shot.

  • Great 
  • Callie Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1101 W: 95 N: 2610] (7555)
  • [2005-05-19 15:37]

Splendid!! My hoed af vir jou details and kompo - fantastiese skoot, and good note too.!TFS

  • Great 
  • naki Gold Star Critiquer/Silver Workshop Editor [C: 382 W: 27 N: 5] (40)
  • [2005-05-19 15:41]

Hi Gerhard, very nice capture. Those are great hunters. It's a very good diagonal composition here with plenty of details ( a bit oversharpened I think).
Very good note as usuall.
Great work.
Thank you for sharing.

excellent shot Gerhard, very great details and Dof
In a friendly way Christophe

Hello Gerhard
Fantastic capture.
Very Sharp.

Halo Gerhard!
Great macro shot! I love your photos. You should post something more often ;-)

  • Great 
  • Fisher Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1540 W: 309 N: 2234] (8915)
  • [2005-05-19 17:39]

Boy, that monster lens sure gives you some awesome shots.
Nice one, excelent composition and details.


Hello Gerhard!
Wonderful macro again.It's so close and sharp.Thanks for sharing.

  • Great 
  • red45 Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 2636 W: 74 N: 9091] (31094)
  • [2005-05-20 3:44]

Superb Gerhard! Details are incredible same as sharpness and quality. DOF is perfect. And what a moment! Cruel but very interesting. Great post!


  • Great 
  • TAZ Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 2241 W: 47 N: 3167] (10926)
  • [2005-05-20 3:46]

Belle et intéressante composition en diagonale bien réalisée pour cet insecte. Jolies couleurs et bonne netteté.
Interesting & very well done !

  • Great 
  • dew77 Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 4432 W: 248 N: 4028] (13270)
  • [2005-05-20 4:17]

Hello Gerhard!
Amazing macro with very clear details.Lighting,sharpness and composition are perfect.

Hele goede foto gerhard.
Prachtige actie foto, met 2 paar ogen, het slachtoffer en de overwinnaar. Very good macro fantastic pov and a very good dof to, well you know it my friend this is a very good job you did, goed gedaan,
gr. jaap

  • Great 
  • sAner Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1455 W: 74 N: 1426] (4750)
  • [2005-05-20 6:09]

Hello Gerhard,

The details are really crisp and clear; razorsharp!! :) Fantastic colors. Very well composed and exposed. Very well done!


  • Great 
  • jossim Gold Star Critiquer/Gold Note Writer [C: 1538 W: 5 N: 2240] (12636)
  • [2005-05-20 6:09]

Félicitations ! Une netteté et des détails impréssionnants.

  • Great 
  • puffy Gold Star Critiquer/Gold Note Writer [C: 289 W: 0 N: 339] (1351)
  • [2005-05-20 8:48]

Hi Gerhard, long time no see, how have you been? Ah.. I see you have a new friend. :P

Great macro shot, excellent composition, DOF and sharpness, as usual, notes are great and photo is perfect!

Thanks for sharing and great to have you back... :)

Fantastic job Gerhard! Very well composed with superb details..Excellent DOF and POV. The prey is well seen.. Hey, I can see that little fly shriveling-up right before my eyes! ;-) Very well done!!

  • Great 
  • Esox Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 239 W: 20 N: 344] (972)
  • [2005-05-20 13:04]

Nice to see you.
Wonderful shot.
All the technical stuff is simply perfect.
The composition is very equilibrated, with this simple but terribly efficient diagonal.
The subject's action is stunning too.
Very complete note too.

Wow. the details are amazing.. pin-sharp as usual. POV and compo are great too :)

hy is sommer mooi van lelikgeid !!


  • Great 
  • deud Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 438 W: 11 N: 534] (2540)
  • [2005-05-31 6:52]

Amazing focused on subject! Details are great. congratulations

Calibration Check