The monarch caterpillars have been contributing to the stress in our lives recently. While our backs were turned, they stripped the plants in vegetable garden to the point where not a single leaf remained and then they started the exodus in search of more plants. I knew this had happened because I came across some intrepid souls in the middle of the driveway heading off to goodness knows where. As the nearest plants were in Mark’s terrace gardens a good 100 metres away, I didn’t like their chances of finding them so I had to do a manual transfer.
In preparation for the late autumn famine and in an attempt to get sufficient population wintering over, Mark sowed fifty metres of swan plants in a nursery block across the road. As these plants are only about 10cm high and already sporting eggs and baby caterpillars, he has regretfully come to the conclusion that he will need to practice some infanticide in order to allow these plants to grow sufficiently to achieve their purpose. The culling now will allow the survival for the greater good of later generations of caterpillars.
New Zealand is sadly lacking in a range of spectacular butterflies enjoyed in many other countries of the world. We have some beautifully marked moths but you need an eye for detail and an appreciation of understatement to perceive the beauty in moths. In the butterfly stakes, the miserable and unwanted cabbage white probably rules supreme in numbers. Red and yellow admirals are extremely rare around here but then so is their preferred host food of stinging nettles. The common copper doesn’t quite rank up with the admirals and monarchs.
In common parlance, a species indigenous to New Zealand includes those that arrive without assistance (this means that coconut palms up north are native now because there are instances where they have washed ashore and taken root). So I guess whether monarchs might now be regarded as natives here depends on whether the first butterflies were perhaps blown over from Australia, or whether somebody introduced them. But they do not, as far as I know, have any negative impact here and only enhance our visual environment.
Butterflies do on occasion blow over from Australia and are not unknown on the north coast of Taranaki. Our elder daughter spotted the lesser wanderer caterpillars on her grandmother’s swan plants at Urenui when she was very young. They were the usual black and yellow caterpillar but smaller and with an extra set of antennae. They morphed into a small monarch type of butterfly with slightly different markings but failed to naturalise despite our best efforts. The large and spectacular blue moon butterfly arrived tattered and exhausted after its long trans Tasman flight and despite Mark’s attentions, it failed to reproduce before it died. It would have been a showy addition to the summer garden.
So all we have in the showy butterfly line is the monarchs and they need some care and attention to their food source to flourish. I read a letter in the Weekend Gardener from a woman who works on three established plants. She nets two to prevent butterflies from laying eggs on them and restricts the caterpillars to one plant at a time. We can’t quite work out how she stops the caterpillars themselves from migrating to the two netted plants. Monarch caterpillars seem perfectly capable of finding swan plants even some distance away but this system seems to work for her. With plenty of space and having saved seed, Mark is more of the overkill type where he hopes his 50 metre planting will ensure continued food supplies.
The bottom line is that monarchs really only like swan plants (asclepias), or milkweed as it is sometimes referred to overseas. The term swan plant comes because of the seed head which is shaped like a swan and full of white fluff which enables the little black seed to become windborne and disperse more widely when the seed pod bursts. Desperately starving mature caterpillars will apparently eat pumpkin or melon flesh to stay alive and chrysalis but I have never heard of anyone successfully raising monarchs from egg to butterfly on anything other than swan plants.
Fortunately swan plants are very easy to grow from seed and if you can keep your swan plant from being decimated during the season, it will flower and seed freely. We had a truck in collecting plants here this week and we noticed it had a load of swan plants destined for a garden centre so if you want to buy one to get you started, ring around and see who has them in stock. Just be warned that if you buy a plant, you will need to keep it netted until it gets established or you will find that a stray butterfly will find it and lay its eggs while you are not looking.
Raising monarch caterpillars is loads of fun, unless you have the distressing experience of running completely out of food for them, and I am of the view that it is mandatory for parents and grand parents to introduce children to the delights of the life cycle of the monarch. Later in the season, Mark starts a hospital where he saves chrysalis which are in danger because they have been spun in inappropriate locations (at times some caterpillars are unwise enough to metamorphose on the swan plant where their brothers and sisters then eat the supporting stem, or on nearby plants which may not last long enough for them to hatch). The chrysalis need to hang in order to develop and hatch cleanly so he used to tie a fine cotton thread to the tip but has now graduated to the faster but less aesthetic masking tape, hanging them from a safer place. He does not get 100% success rate from this intervention, but the row of chrysalis hanging from a bar in front of one of our windows keeps us mildly entertained.
We have had occasional years when we have had good numbers of monarch butterflies wintering over in our garden and it is a joy and delight to see them stretching their wings together on a sunny winter’s day. They tend to congregate in one spot over winter. But every year we manage to keep at least a few resident around here to start us off again for spring.
If you want to know more about monarchs, there is the Monarch Butterfly NZ Trust whom you will find at www.monarch.org.nz
On another topic entirely, Mark has a yen to own a Planet Junior, a manual tilling device from way back, decades ago. If anybody has an unwanted Planet Junior in a back shed, he would be really pleased to hear from you. My attempts to locate him one on Trade Me have failed so far. We could promise said PJ a good and appreciative home.