Native Foodplants Essential for the Caterpillars of Butterflies and Day-flying Moths
The Hungry Caterpillar
Caterpillars have special diets, and identifying and providing these is the key to welcoming breeding colonies of butterflies to our garden or other greenspace. To be of maximum value to butterflies, our garden needs to be a restaurant for the whole butterfly family, not just an adult-only nectar bar.
Caterpillar Foodplants Lost to Habitat Degradation
Everything the butterflies need should be out there in the countryside already, we shouldn’t need to do anything, but habitat degradation has put paid to that, and we now find ourselves in the position of having to reintroduce the missing foodplants so essential to the caterpillars. But first we must know what these foodplants are, make ourselves familiar with them.
Navigating the Website
You may have come to the Foodplant tab directly. Or you may have arrived via the Butterfly tab, selected a butterfly of interest, identified the foodplant of its caterpillars and now wish to find out more about the plant. Either way you can scroll down the Foodplant menu, select those of interest and meet more of the butterflies whose caterpillars feed on them. In most cases several species of butterfly will stand to benefit from us growing a single foodplant.
Grow the Missing Foodplants
Not lucky enough to have them growing on your land already, then the third step is to take the plunge and buy the foodplant, either as seeds or plug plants from one of the excellent wildflower suppliers like Emorsgate and Scotia to be found on the internet.
Commercial Wildflower Mixes
While the simplest solution might seem to be to sow one or more of the many excellent wild flower mixes available from internet suppliers, unfortunately, while such mixes might contains twenty or more types of wildflower, only three or four of these are likely to be considered suitable for egg laying by the local butterfly community. They are typically pollinator mixes designed to provide a succession of flowers over a long period. Excellent! But if we want to do more than attract butterflies to our greenspace or garden for a brief nectar stop, we need to make sure that their specific caterpillar foodplants are available in the right place at the right time, otherwise the female, sensing she has nowhere suitable to lay her eggs, will move on. She selects the correct foodplant by sight and smell. It must provide the correct nutrition, be non-toxic to the caterpillar, provide camouflage, and often, contain chemicals it can concentrate in its body to make it unpalatable to predators.
Add Extra Foodplants
Check the mixes out, and if they don’t include all of the food plants you need, add them. Purchase them separately, either as seed, or to gain a head start, plug plants, either from the same seed company or one that specialises in wildflower plugs.
Caterpillars don’t always eat the leaves of the plants with the pretty flowers. Those of the Small Copper, one of our most common and easily handled butterflies is tied to Sorrel. As it’s wind pollinated, Sorrel naturally doesn’t sport large colourful flowers to attract insects. And as we are all aware, the caterpillars of several of our biggest and brightest butterflies feed on stinging nettles which though not exclusively wind pollinated still only have small flowers, leaving the adults to seek their nectar elsewhere. It's clear that not every caterpillar foodplant has pretty nectar-yielding flowers, but as flowers are just one of the many fascinating attributes of a typical wildflower, all are worth growing.
It is important to remember too that each and every wildflower in a commercial mix, even if it does not provide food for butterfly caterpillar, will be the larval foodplant of one insect or another, in all likelihood of dozens, so is well worth having in our garden or greenspace.
Some wildflowers, like Scabious and Hedge Garlic do in fact supply the complete package, with nectar-rich flowers to delight the taste buds of adult butterflies, and juicy leaves and buds to supply the needs of their caterpillars.
As butterflies are among the most easily observed of the invertebrates, how many butterflies and the number of different types seen flying around an area is a useful indicator of the health of the surrounding countryside and its biodiversity. When butterfly sightings fall it usually means that biodiversity as a whole is in decline, both plants and invertebrates.and ultimately birds and other animals that depend on them for food. The drastic fall is the numbers of all but a few butterfly species in the past few decades says it all.
As well as individual plant names you will also come across a tab entitled Overwintering.
This section will emphasise the importance of ensuring that overwintering sites for insects are available, and the need to provide them if they are not. Cracks in trees, piles of logs or fallen leaves, hollow stems and tussocks of native grasses, old sheds, are the sort of thing we are looking for. In the long term all animals need both food and shelter in order to survive.