Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Friday, February 07, 2014

Imperial Hairstreak Butterfly in Eucryphia bushes in Robertson

Today I was amazed to find a Butterfly I had read about, but never seen before, in the iconic plant of Robertson, the Eucryphia.

This plant, Eucryphia moorei is also known as "Pinkwood". There are a few growing well in "Pinkwood Park" which is a small park directly uphill past the Post Office, on the Illawarra Highway, Robertson. These young trees are growing well, having been planted there a few years ago, by members of Robertson Environment Protection Society, under the guidance of Dr David Tranter. They are currently in full flower.

The Butterfly I saw is seldom seen
more than 20 metres from a food plant.
In this case an Acacia melanoxylon is visible
in the background of the photograph.
Imperial Hairstreak Butterfly
Jalmenus evagoras
(synonym: Common Imperial Blue)

This pale-looking Butterfly has
blue colourings on the upper side of its wings.
But it also has these strange little protrusions
on the tail ends of its hind-wings.
This is said to be a decoy pattern,.*** 
to make the rear end of the wing
look like the head-end of a different insect
Here you can see the blue patch
on the upper side of the wings.
Males are brighter blue than this (presumed) female

On this shot you can see the
uneven edge to the hind wing
which is said to be part of a decoy pattern
to confuse a possible bird predator.

The fully ripe flower of the Eucryphia,
with dots of pollen grains visible on the stamens.
The sweet perfume of these flowers was very evident
in the warm weather today.

 The first thing I ever heard about these Butterflies is that they have an symbiotic association with Ants. The ants protect the larvae of the caterpillar, in return for obtaining an extrusion from the caterpillar. Normally one would expect the ants to regard the caterpillar as food (prey) rather than a food source. However, in this genus of Butterflies, ants actually protect the caterpillars from wasps and other predatory insects and spiders. This is described as an "ant-related mutualism" and is well described in this brief article.

These Butterflies are very closely associated with plants of the Acacia genus (the food plants of their caterpillars). Robertson is well supplied with Blackwood Wattles, Acacia melanoxylon, a recognised food plant for these insects.

*** Decoy Pattern
The coloured tails of the butterfly look like white-tipped antennae on bright red/orange and black colourings which, with wings folded (the habitual posture) makes the back end of the butterfly look like the front end (the actual head and antennae being quite bland). This is perhaps a decoy perhaps in case of bird strike.
See this photo
That text about the decoy pattern is courtesy of the Butterfly House website.

No comments: