Friday, November 21, 2014

Butterfly Season

What a wonderful butterfly season we are having this year.
I suppose you have all noticed that this is a big year for caper whites (Belenois java teutonia)?
This is the butterfly with the fairly plain wingtops, white with black edging,


and the beautifully marked underside which you only notice if you look a little more carefully, or see one at rest.

I don’t think anyone knows quite why they sometimes have a spectacular year like this. We haven’t had one since before the 2011 floods, so perhaps they do better when the weather is dry.
People speak of them “migrating”, which suggests a purposeful journey with a planned end in mind. What they are really doing seems to be more of a random radiation. Perhaps they have exhausted their local host plants and are simply flying away in hope of finding more. They turn up in great numbers in the southern states where the host plants don’t occur naturally. There manage to find the few cultivated specimens, where they can be seen flying in a whirling mass around the plant. The males and females fly in separate migrations, but obviously succeed in meeting up, as they have been seen laying eggs in Victoria. (If they can’t find a caper plant, they lay on unsuitable plants, and the caterpillars die.)
They also fly out over the Pacific Ocean in their many thousands. Odd specimens have been known to turn up as far away as Samoa.
The butterflies breed on our local native caper plants, Capparis arborea, C. mitchellii, C. lasiantha and C. sarmentosa. Like most local butterfly host plants, gardeners rarely plant them, so the butterflies breed in the country and can only be enjoyed in our towns because they are strong flyers who will often drop in for a refreshing sip of nectar in our gardens. (Butterflies with less strong flying skills and migratory urges are disappearing from our urban areas, as they just can’t make the flight from the increasingly distant breeding sites.)
Most of our local native capers grow on country roadsides. They are prickly plants, so are grown only by butterfly enthusiasts, and tend to be cleared from farms and acreage estates by owners who don’t want to deal with the prickles.

They can also be completely defoliated whenever the butterflies have a big breeding year. They bounce back to beauty and good health afterwards, with all the freshness of a well-pruned plant, but the only people who grow them are those who value the cloud of lovely butterflies more highly than a high standard of year-round perfect beauty from their plants.
Roadsides are potentially subject to clearing for road-building, as our population increases, as well as “beautification” by those who prefer a well-mown, neat and tidy road verge to native vegetation. Depending on your personal aesthetic and philosophical viewpoint, a natural roadside environment is a rich and  environmentally productive ecology, or an ugly “hotch potch”. Unfortunately, destroying a patch of biodiversity is very, very much quicker and easier than replacing it, so the people who think nature needs tidying up, and are prepared to do something about it, have a disproportionate  advantage, when it comes to living in their preferred Australian landscape type.
The long-term future may hold fewer of these spectacular caper white population explosions. Let’s enjoy them while we have them.
For more on this butterfly and its host plants, see my posts for November 19, 2009 and December 4, 2008, or simply type the butterfly’s name into this site’s white search box at top left.






4 comments:

National Park Odyssey said...

Thanks for all this information. We live on the Sunshine Coast and some years we have large numbers of Blue Tiger Butterflies (Tirumala hamata)"migrate" along the beach and coastal reserves.It is an amazing sight to see.

Patricia Gardner said...

Glad you enjoyed it!
We have the same thing in Toowoomba, with large numbers of blue tigers, though it hasn't happened for some years now. But there is still plenty of summer to go. Do you have any idea why some years are better than others for them?
Trish

Rayleigh said...

Hello Patricia
I live on the sth west corner of Toowoomba and I am enjoying our butterflies as they love the lavender and daisies just outside our sunroom.
I have been trying to capture on video the number of butterflies and different species to share with friends. That sent me on a search - what is a Butterly and what is a moth. I thought I could tell but have learned a lot.

The tiny blue ones on my pink daisies match a photo I found of a Mountain Alcon Blue but I was interested to see that you live in Toowoomba and may have more local information.

Patricia Gardner said...

Hi Rayleigh.
It sounds as though you have a great garden for butterflies. I find that the combination of lavender and daisies is good, too. There were four different butterfly species on mine this morning in the bit of time it took me to drink a cup of coffee.
I am no butterfly expert, but do know some of the locals.
I think your blue butterflies are most likely to be the common grass blue (Zizina labradus) or the tiny grass-blue(Zizula hylax). I suggest you look them up on the internet using the scientific names, as this is often a way to get hold of a better selection of photos. They are both lovely butterflies, expecially if you can get a really close-up view of their markings.
The Mount Alcon Blue is not an Australian butterfly so it won't be that. However our native grass-blues do look rather like it. They breed on the little native pea plants that tend to grow among the grasses, so if there are any of these about they may be the source of your butterflies.
If you are interested to know more about the native peas which attract them, you could go to my blog, and put the word "fabaceae" in the which search box at the top.
Cheers,
Trish