2004 saw the discovery of a curious little butterfly that didn't look
like anything from the region. It wasn't. The Two Spotted Line Blue,
whose numbers explode at the start of certain years, only to vanish
for the rest of the year, is from Australia. It belongs to the genus of
nacaduba which is well represented here but all of our native species
are forest inhabitants. This one prefers dry grassland, similar to the
Aussie bush I experienced during my trip. Ever since its arrival at our
shores, I hadn't been able to see it. This time I got lucky.
There were literally hundreds of them. From afar, they looked just
like the all too familiar grass blues seen everyday by the roads.
Here's the give away: they were circling and swarming around acacia
trees. Acacia auriculiformis. Roadside grass blues don't have any
business with these trees. These are the Australian trees that the
Australian butterfly wouldn't be around without.
The acacia was intended as an ornamental plant but it is no longer
planted here; it's become an invasive weed, popping up wherever
it can. The sickle shaped leaves are not actually leaves. They're
flattened stalks. The true leaves only grow on the saplings and are
bi-pinnate like a usual legume's. The butterflies don't want the flat
stalk extensions. They lay their eggs on the sunny yellow flowers.
While in theory, more butterflies translates cleanly into more chances
for photography, the reality is quite the opposite. The butterflies are
everywhere. One comes down to a patch of grass. You get ready
but then another five come and attack it. There are plenty resting in
the shade but they're so small and difficult to see and the moment
you do, they do too; off it goes. You end up waiting three hours for a
more willing model.
The male is pale purple and blue on top and the female is a plain
brown. The underside sometimes has a faint orange blush on the
forewing, more apparent in the pristine specimens. they are small,
with wingspans of only 2 cm. Here are two record shots of the
ones that didn't want their portrait taken.
Now, the hundreds have dwindled to twos. It won't be long until the
butterflies completely disappear from the acacias and for the rest
of the year.