Tuesday, 17 January 2012

Insects weird and wonderful

A key reason for photographing, and blogging about, insects is to reflect on the extremely diverse forms they take.

This could be exemplified by this image of a basic member of the family Diptera, feeding on a garden daisy of some form.
These are extremely common, but when the detail is viewed, incredibly complex.

On the subject of 'common' on the night of 18 January a beetle swarming occurred.  This was the scene around our outside lights at 10:30 while escorting the small dog on her toilet break.
Less common is the next selection.  We noticed these on an Acacia pravissima bush beside our drive.  Only one, fairly isolated, shrub seemed to be infested.
 My first thought was that they were snails but on looking more closely realised they were soft and totally unlike snails!


My next thought was that they seemed to have moth-like antennae but on closer looking again, from head-on,  that may have been a leg?
They stayed in the same position all day so I went out this evening to see what was going on.  Ants were going on!  (Sorry about the quality of the next image:I'll try to do better tomorrow night - see below.)
This started me thinking about aphids and on consulting my Field Guide in that part of the Insect world I found a pretty close match with Icerya purchasi "Cottony cushion scale" which feeds on Acacia in Australia but is/was a big pest on Citrus in the USA.

It is now the 'next night' and I think I have done better in the image department!
I have left the original image so that the reader can see "before and after" shots.  The principal difference - as far as I am aware is that in the second image I used a halogen headlight to illuminate the target area.  This meant that the camera was able to auto-focus on that (in zoom-macro mode) rather than attempting to do so in the brief time the flash was active.

The story continues to develop!  On checking the scale insects this morning I found that a number of them had small red dots on them.  After considerable swearing and more constructively, work on my breath control, I was able to get an image of the detail of the red dots.
My initial thought was that these were some form of parasite but referring to the University of California site revealed that these are first instar crawlers of the scale insect itself.

4 comments:

Denis Wilson said...

Nice work identifying your "Scale" insects.
The ants will farm them, which might be interesting to track.
They keep moving the scale insects up the bush onto fresh growth, I understand.
Good shot of the fly. Contrary to popular opinion, many "blowies" are attracted to pollen. Tea Trees in particular seem to be very attractive to flies.
Cheers
Denis

Jacana said...

Amazing photos and information.

Flabmeister said...

Denis, Jacana

Thanks for comments. I have added a far better picture of the night-time ants!

Martin

Denis Wilson said...

Excellent work.
By you and the Ants,
Denis