Just the other day I was admiring the Fuchsia ‘Display’ and the miniature arum Denise gave me years ago. I was thinking how good they both looked at this time of the year. When I went to empty the rain gauge after the wonderful rain we had (50mm overnight!), I could not believe my eyes: whereas the fuchsia stood leafy and proud yesterday, now there remained only the skeleton of the plant, and only the stems of the arum! I found the culprits; sleek bullet train caterpillars with colourful false eyes and a cheeky upright tail at the end, munching away at what little was left of the foliage. The temptation was great to pull them off and squash them under foot. Did I kill them? No, but one did experience its very first flight before he or she turned into a moth. My annoyance turned into reason – the plants are destroyed but they will come back again, and why should these creatures not be allowed to complete their cycle of life?
We all admire butterflies darting from flower to flower in our gardens. Some gardeners even plant special plant species that attract butterflies, but few of us give very little thought to what they were before they transformed into these beauties admired by all. Butterflies and moths undergo complete metamorphosis. Males usually start emergence earlier than females and peak in numbers before females. Both of the sexes are sexually mature by the time of eclosion (emergence). Females of most nocturnal species, including almost all moth species, use pheromones to attract males, sometimes from long distances. Mating and the laying of eggs are carried out by adults, normally near or on host plants. In many species, the female may produce from 200 to 600 eggs, while in others, the number may approach 30,000 eggs in one day. The larvae are commonly called caterpillars and they eventually grow into beautiful butterflies or unassuming moths, but to make the transformation, they need to devour large amounts of plant material.
Some caterpillars, such as hawk moths, can strip a plant of its leaves in a single night. As the larvae grow they change in appearance, referred to as instars, and once fully matured the larva develop into a pupa, referred to a chrysalis in the case of butterflies and into a cocoon in the case of moths.
The larvae of both butterflies and moths exhibit mimicry to deter potential predators. Many have false eye-spots to enhance this effect. Host plants often have toxic substances in them and caterpillars are able to sequester these substances and retain them into the adult stage. This helps make them unpalatable to birds and other predators. Such unpalatability is advertised using bright red, orange, black, or white warning colors. The toxic chemicals in plants are often evolved specifically to prevent them from being eaten by insects. Insects, in turn, develop countermeasures or make use of these toxins for their own survival.
While some moths suck nectar, others don’t eat at all. After it emerges from its cocoon, it lives for about a week. Its sole mission in life? To mate and lay eggs. Butterflies and moths fulfill a vital role in nature; they are not only great pollinators but also food for everything else. An estimated 95 percent of nesting birds rear their young on insects, and caterpillars make up a significant part of that.
Pesticides will kill most caterpillars, but the chemicals also kill other beneficial insects, such as ladybugs, earthworms and predatory wasps. By killing insects you are also depriving creatures such as bats, birds, and frogs from a vital food source.
As you get older you learn to live what nature throws at you and to be more philosophical about gardening. My catastrophe is not the end of the world as the leaves will sprout again, and flowers will appear again – look at it as being part of nature’s restaurant!
Contributor: Esther Townsend