Friday, 20 March 2009

Daylight robbery

A robber in my garden
Since yersterday, I have been an eye-witness to a robbery taking place in my home garden at broad daylight. A pair of robber flies has taken residence on some of the sticks that I have erected to invite dragonflies to perch. Ssing them as launching pads, the robbers have been launching precision air strikes to hunt on various tiny insects.

With their large compound eyes and three simple eyes situated in the depression in betweeen, they have amazing eye sight, and hardly any fly in the vicinity that falls within their target size goes unnoticed.

On several occassions I saw a perched individual fly in the opposite direction to take insect prey in mid-air!This particular species of robber fly, measured barely a centimetre in length, was a pretty amazing killing machine.
A robber in my garden
Once the victim is caught in mid air, it returns to the perch to 'process' the meal. First, it uses its short proboscis to inject venom— its saliva containing neurotoxic, and proteolytic enzymes to first paralyze, and then to digest the insect's inner parts. Thereafter, puting its proboscis to good use, it cold-bloodedly sucks the liquified meal like a milkshake.

And once it is done, the victim's lifeless outer casing is discarded like a used satchet.

A robber in my garden
Robbers belong to insect order: Diptera to which 'true flies' belong. They possess a single pair of wings. All Robbers belong to the family, Asilidae. Their quite impressive prey menu includes other flies, beetles, butterflies, moths, bees, wasps, spiders, dragonflies, damselflies and grasshoppers!

A robber in my garden

22 comments:

RyanM said...

Great post as always Amila - lots of good info !

Java Jones said...

Hi Amila - I had the chance to observe a Dragonfly feeding at night (at Flowerbook) in the glow of a CFL light. It was zipping around cleaning up the insects around the light like a vacuum-cleaner. The speed and accuracy was amazing. I related this incident to another 'specialist' and he said he hadn't heard of Dragons being nocturnal hunters.

What do you think?

flowergirl said...

Wow, what a post! I didn't know this is how these things go about their meal, I mean the milkshake bit!

Amazing!

spookydragonfly said...

WOW!...Absolutely stunning captures, Amila! What an interesting post...I can always count on you for accurate information.

Gallicissa said...

Hi Riyazi,
Thanks a lot. I am sure your Robbers will be out soon.

Hi Java,
Thanks for sharing this observation.
There are no completely nocturnal dragonflies. The one observed by you sounds very much like a ‘dusk-flying dragonfly’, which often blunders into human dwellings, distracted by the lights. As they crash into houses at nighttime, it is easier to get fooled that they are nocturnal. But in actual fact they are not. When the darkness of the night fully engulfs, they retreat to their roosts.

Note these ‘dusk-flying dragonflies’ can be seen flying and feeding actively even at midday in shaded ponds and streams that are surrounded by thick vegetation to cast enough darkness to simulate dusk-like conditions. So, these dusk-fliers are not completely disadvantaged by having a very narrow time belt of the day to operate.

Two dusk-flying dragonfly species that you could get there are Indian Duskhawker Gynacantha dravida and Dingy Duskflyer Zyxomma petiolatum. The first one shown here is the one that mostly crashes into houses. I have both these species in my garden.

p.s. If you scan the vegetation beside the pond, you could spot them roosting during daytime in dimly-lit confines. And when you do not have thick vegetation flanking your pond/streams, they are found roosting away from the water in the available dense thickets. They are quite cryptic, so you have to scan very carefully. One more hint: usually the Indian Duskhawker is found resting vertically while the Dingy Duskfly is at an angle of about 45°

Hi flowergirl,
Thanks! Oh yes, the milkshake bit is very true!

Hi Kim,
Thanks! I am pleased you liked this post. I get a narrow time band in the evening to observe these robbers in the shade. They are as interesting as dragonflies!

Java Jones said...

Thanks for the info Amila - I wanted to photograph the critter, but it was so fast and active, I just couldn't. Anyway, I was watching 'Revolutionary Road' at the time, so..!!! It appeared to have an orange body. Will check my Dragonfly book when I get back to the hills on Wednesday to see if your suggestions regarding the species look probable. It was indoors, about 8pm, and as I mentioned, hunting around the light that attracted lots of midge and mosquito-type insects.

Sunita said...

Ouch! It must hurt to see these robbers using the twigs you put up for the dragonflies to hunt them.

oldcrow61 said...

These shots just blow me away. Amazing! Great information as well.

Chriss said...

Simply stunning images. Very informative post too. Have a wonderful week.

Gallicissa said...

Welcome back, Java,
Yes, it is a nightmare trying to photograph dragons in their active feeding modes. Much easier to find it in a roost, when they are resting. Since you mention your dragon was orange, another possibility is Wandering Glider Pantala flavescens. It is the world’s most widely distributed dragonfly and the only dragonfly Borneo shares with England. It is a reputed temporary pool breeder and takes part in migration in search of temporary pools. The rains we had a few days ago may have triggered their arrival.

One thing I failed to mention in my reply was even non-dusk-flying dragonflies blunder into houses, distracted by lights!

BTW, the link to the Indian Duskhawker is here.

p.s. I saw the trailer of that movie. It looks good.

Namaste Sunita,
I have no complains about robbers using dragon sticks!
They are full of character and make good macro subjects.

Hi OC,
Pleased to hear those comments!
I look forward to you spring posts.

Hi Chriss,
Thanks! And happy 1st blogoversary again!

Atanasio Fernández García said...

Hello Amil, you have a very interesting blog. The macros that you get from this predatory flies are really spectacular!. In Spain are common flies of the family Asilidae, ruthless killer of other invertebrates. Regards!

Doug Taron said...

That's some amazing macro work there. Excellent series. I need to learn more about our robberflies.

Christopher said...

Wow, wow, wow. I know I've said it before, but really, your macro work is simply amazing - beyond anything else I've seen. Have you ever considered publishing a book of your work?

Gallicissa said...

Hi Atanasio,
How nice to hear from Extremadura!
I am very pleased to read your comment, thanks! You are absolutely right about Robbers being ruthless killers of invertebrates. Sometimes I get this feeling that they kill for fun! The ones over here at least seem to have an instaiable apetite.

Hi Doug,
Thanks! I had different pics in this post initially and replaced with new ones that I got yesterday.

Hi Christopher,
Thanks! I am pleased to hear your compliments. I started to do serious macro work only recently and do not have a good enough collection yet. But in the future I will publish them in a book. Thanks for suggesting it!

Susan Gets Native said...

Whoa!!!

Their eyes remind me of when we used to own one of the "old" TV's, the ones with tubes. If you got your face close enough, you could see the pixels.

S.C.E. said...

So you got a macro rig instead of a 100-400L!

Those photos are quite amazing. Wow.

Gallicissa said...

Hi Susan,
All of the top three images were shot at 5 times the life size. They are rich in detail due to that.

Hi Stu,
Yes, all for a good course! That beast will have to wait a few months...

fishing guy said...

Amila: What an amazing close-up of a neat animal. That eye shot is amazing.

Gallicissa said...

Hi fishing guy,
I shot them all hand-held and I very pleased about the sharpness.

Pseudothemis zonata said...

Good morning.
Your blog is nature itself. Your world is very splendid. I look absorbedly. I can enjoy rich nature of your country from Japan far across sea. I show sincere thanks to you.

Aamina said...

wow i'm astounded...ur pictures r absolutely brilliant!
i'm thinking of gettin a macro sometime soon....its for a nikon d300..what would u recommend?something reasonably priced..
shud i get a nikkor or will a sigma or tamron be just as good?
which one do u use?

Gallicissa said...

Hi PZ,
Good to hear from Japan!
I look forward to see your dragonflies soon. Thanks for your glowing tribute.

Hi Aamina,
Thanks! I am afarid I know very little about Nikon lenses. I use Canon 100mm macro and 65mm mp-e macro lenses and the two macro flashes. If you search the web, you should be able to find a recommended Nikon rig for close up work. I think Canon leads the way in extreme macro capabilities - with only Canon 65mm mp-e capable of taking up to five times the life size (5:1) close ups.

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