Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Tuesday, June 22, 2010

The Eyes and Antennae of the Moth

These are not new photos. I took them in mid May, but since then I have posted about the birds of West Wyalong and other things, and I realised tonight that I had skipped over posting these images.
Silly Me!

Here is a Swift Moth (Oxycanus dirempta) which was quite passive, early one cool evening., last month. The eyes are reflecting the flash of my camera.
Here it is patiently sitting on my finger.
Note the hairy legs, and the huge compound eyes.
Interesting patches of mauve colour too.
(Click to enlarge the image.)
And now for the "Pièce de résistance".
The face of the Moth, with antennae fully extended.
(Click to view larger image)
Note especially the minute tips of the small branches on the antennae.
What looks like a "haze" around the antennae
is actually these tiny sense organs, virtually touching eachother.
This moth is almost certainly a male, with antennae set to track down a female. "In moths, males frequently have more feathery antennae than females, for detecting the female pheromones at a distance." (Source Wikipedia - lepidoptera - communication)

Not only are the antennae set with obvious, but tiny branches, ("plumose antennae" or "feathery antennae") but at the ends of each "branch" there are minute "feelers" which are virtually microscopic (sensilla)***. Their purpose is to detect the sex scent (pheromone) of the female. And they are extraordinarily good at it.
  • "Pheromones are odors that are used for communication. A female moth may release a pheromone that can entice a male moth that is several kilometers away."
It makes one realise that Moths ought be employed by French Parfumiers to design their next range of scents, for we humans are mere amateurs at this "scent" business.

*** Sensilla: "The number of multiporous hairs is usually large, since the greater the number, the greater the chance that molecules in low concentrations in the air or water will make contact with a sensillum. In insects the length or complexity of the antennae is a reflection of the numbers of multiporous sensilla. In insects requiring increased sensitivity, the antennae are branched, providing a larger surface area on which more sensilla can be accommodated" Encyclopaedia Britannica (web version).


Nature ID said...

The reflective eyes are incredible. Great pictures!

mick said...

That last image is stunning! The antennae are fascinating.

Denis Wilson said...

Thanks Katie.
Nice to meet up, after both being involved with the Moth and Me #12.

Denis Wilson said...

Hi Mick
I will try again to get even more detail of another Moth with large antennae.
They remind me of wavy little things one sees in rock pools (the antennae bits I mean).
Nature has ways of using common forms for similar functions (filter feeding, and "sampling the air" are analogous, after all.)