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Paralecanium Expansum Metallicum (scale insect) by melvynyeo Paralecanium Expansum Metallicum (scale insect) by melvynyeo
Found another Paralecanium Expansum Metallicum... this time it's goldie in color. This is a backlit photo showing what might be its eyes and legs :) Taken at night in Singapore forest.
Normal light…
Sliver color…

Quote from

Most soft scales, and members of several other scale insect families, have a strange life cycle that involves spending almost their entire lives in a sessile (immobile) state.

Paralecanium expansum metallicum life cycle

First-stage nymphs, termed crawlers:
  • hatch from eggs that are protected underneath the adult female’s body
  • can walk short distances
  • act as the main means of dispersal from one plant to another, or from one area to another
P. expansum metallicum crawlers provide a very effective means of dispersal as they are:
  • only 0.5mm long
  • extremely light
  • readily carried by air currents
Once the crawler has selected a feeding site it undergoes its first moult.

From the second stage onwards
P. expansum metallicum females:
  • do not have functioning legs. Adult females don't even have the vestiges of legs
  • simply feed on the host plant’s phloem sap: if the plant dies, so do they
Some other soft scales do have short-but-functional legs but mobility is still extremely limited.In complete contrast to females, male scale insects have:
  • long legs
  • a single pair of wings in most cases
  • no functioning mouthparts
So they have very limited time in which to seek out females in order to mate.

Paralecanium expansum metallicum lives in forested tropical environments in south-east Asia.In forests, the metallic females may resemble splashes of sunlight filtering through the canopy, perhaps explaining how this feature has evolved.It, and other members of the genus Paralecanium, seems to prefer feeding on the upper surfaces of leaves.

P. expansum metallicum develops in small colonies on the upper surfaces of the leaves of its hosts, whereas most other phytophagous bugs take advantage of the shelter afforded under the leaves.The presence of the adult female is betrayed by a silver-metallic sheen, almost certainly a form of iridescence. The living insect appears like a splash of metal solder on the leaf.While scale insects are generally regarded as pests, many are actually specially adapted to natural habitats and so habitat conservation is an issue. P. expansum metallicum is likely to be at risk from habitat loss.
DancesWithDreams Featured By Owner Aug 11, 2014  Hobbyist
What a strange being! I'd never heard of those before. Also, a beautiful shot, as always.
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Submitted on
August 11, 2014
Image Size
915 KB


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Camera Data

Canon EOS 5D Mark II
Shutter Speed
1/160 second
Focal Length
100 mm
ISO Speed
Date Taken
Jul 19, 2014, 1:23:23 AM
Adobe Photoshop CS4 Windows
Sensor Size