Photo Essays

March 28, 2009: Argyrodes and reflections

Learning links

About Argyrodes flavescens (Wikipedia)
About kleptoparasites (Wikipedia)

Surprise - this is Jalan Besar Stadium where Wang Yang and I watched the football game last night

mar 27 6198 jalan besar

We sat close to a very noisy drummer

mar 27 6207 drummer

There were two mascots - #1

mar 27 6216 mascot

and #2

mar 27 6221 mascot

The score at 3 min

mar 27 6272 sign

A kick

mar 27 6297 kick

and a push - and so it went for 90 min. Final score: 1-1

mar 28 6280 push

Now to today's visit to our spider observatory. Wang Yang is continuing to improve the quality of his curious eyes. At his height, he sees much more than my old eyes catch from 6 ft altitude. Here a curious ant

mar 28 6349 ant

Wang Yang was busy capturing everything in sight - and most images were not interesting, but this lone drop of dew on a blade of grass caught my attention

mar 28 6395 morning grass

We found last week's Nephila pilipes web - about 1 meter in diameter and this week, as anticipated, it had been invaded by Argyrodes flavescens - our little kleptoparasite friends that steal food from the hostess of the web and when there is no food, eat her silk and the drops of golden sticky glue.

Argyrodes flavescens present a great learning opportunity. Their abdomen is highly polished so that, with careful focus, you can clearly see a reflection of the sky. But the technical issues abound - depth of field, motion artifact, focus on the abdomen, and a good balance of light. I have better luck in early morning when the background is dark than later in the day when the sunlight opens up the background

This is a female as you can tell from the palps.

mar 28 6408 reflection

She was walking around manipulating the strands of the Nephila web

mar 28 6431 argyrodes reflections

Her movement provided lots of different orientations. These were taken with the lens wide open (f/4.5) at 1/125 sec to reduce motion artifact and ISO 400. Using my Tamron 180 mm with a 36 mm extension tube.

mar 28 6455 argyrodes reflections

When I was watching the Ravenel Bridge construction, I played with the sobel transform - sort of a directional edge enhancer - to create something like a digital sketch. Here is what our little friend looks like after image inversion

mar 28 6455 argyrodes reflections inverted

and here is what she looks like after the sobel edge detector followed by inversion and altering the gamma a bit

mar 28 6455 argyrodes reflections sobel

Another try with getting crisp reflections

mar 28 6461 reflections

Here is a juvenile Nephila pilipes. Usually the web is planar, but today there is an interesting curvature to the web and the supporting superstructure

mar 28 6467 nephila web