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1 juil. 2014

Dragonfly, a formidable predator

I suggest here a more detailed follow up to this article, about odonate predation.
A dragonfly feeds exclusively on live preys, whether it is still at the stage of larva or of a winged imago: it consumes a wide variety of insects daily from flies (Diptera), to bees (Hymenoptera), to some beetles, to butterflies (Lepidoptera), or even to other odonates as we can see in the article above mentioned.

It is particularly well equipped to this end:
First of all its compound eyes are the largest in the world, proportionally to its body. Thousands of facets are grouped in separate zones having for function to reveal forms, colors and movements, the latter being perceived much faster than the human eye.
A compound eye will decipher an image much more effectively since it can analyze at very high speed, a higher frequency of the sequential vision (set of images or scenes analyzed separately).

Emperor dragonfly with a Southern White Admiral.
Dr Steven Wiederman and his partner Professor David O' Carroll (University's Centre for Neuroscience Research in Adelaide - link to their original publication) determined that thanks to the thousands of facets  it can focus on a prey located beforehand amongst  many others and is even able to re-align its body towards the target. It is also able to choose one alone in a large insect swarm and to keep stick to the one spotted target.
 These two researchers also demonstrated that the dragonfly is capable of a thought process more sophisticated than thought previously when it hunts down a prey. Thus it possesses intellectual cells for a selective attention, which was only demonstrated up to now with primates.

Scarlet Darter with a fly.

A dragonfly is able to fly at a very high speed and can have lightning accelerations, it also has the faculty to hover and even fly backwards.
Preys are caught by clawed and spiny legs.
The smaller ones are eaten in flight whereas the largest are dissected on a perch.

A 4 spotted Darter with a dusty moth!

Black-tailed skimmer
with a female scorpionfly.

Also a Black-tailed skimmer with a scorpionfly.

Black-tailed skimmer
eating a Common darter.
Clic on pic to reach the other photos

5 commentaires :

  1. Extraordinary macro images, that even showing quite gruesome content in detail, seem beautiful. I had no idea that dragonflies had such multi-faceted vision, or selective attention. A fabulous post Noushka!

  2. Amazing macros Noushka.
    These creatures are almost unbelievable regarding their abilities.

  3. Well this is the stuff of nightmares, even if exquisitely rendered, Noushka! Your dragonfly photos are breathtaking! How do you do it? You're amazing!

  4. Dear Noushka,
    Thank you for this very interesting info. The more one learns about nature, the more it fascinates.
    Also fascinating are your pictures. Very well done.
    Best regards, Corrie

  5. Amazing dragonfly captures, Noushka! You are a fantastic photographer! Thank you for linking up to my critter party. Enjoy the rest of your week!


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