Bees are not the only pollinators under threat, with butterfly populations falling worldwide, writes Fiann Ó Nualláin
Bees are not the only pollinators in trouble; the sad fact is that across the planet butterfly populations are falling dramatically.
A consequence of habitat loss, but also to the impact of Genetically Modified Crops. The plight of the rapid decline of Monarch butterflies (Danaus plexippus) has been linked to the rise in GM maize pollen which has also been proven to be toxic to beneficial lacewing insects (Chrysoperla rufilabris).
Part of the problem is that modified crops are bred to produce Bacillus thuringiensis, a toxin to keep pests at bay, but which is not isolated to affect only agricultural pests, and which can compromise the immunity in a range of insects to the fungus Nosema.
Okay, we can refuse to grow GM crops, we can decline to put the products of GM crops in our shopping trolley and we can campaign and raise awareness amongst our friends, family and fellow gardeners.
But we are gardeners so we can also garden to support butterfly populations. Our gardens can replace the lost habitats and our gardens can host plants that supply food and medicine to our struggling butterflies.
There are many books written about nectar sources for butterflies — save your money. All nectar is nectar to a butterfly. Okay, some butterflies will be more drawn to a thistle over a sedum in the wild, but the ones in your garden will more than likely visit both — and make a few stopovers on other species en route.
Make a garden and they will come. Neglect the lawn and to the daisies and dandelions they will come. The point is — do you want them to stay? If you do, it’s a different food you need to stock.
So here in Ireland we have 32 native butterflies whose adult populations are not fussy at all about what source of nectar they sip from — be it a garden centre staple, an exotic or a native. You don’t have to edit your favourite flowers or garden style to attract butterflies.
But when it comes to laying eggs and those eggs becoming hungry caterpillars, then there are specific plants required to host their young and keep broods going in your garden and neighbourhood. For that, the natives like the natives.
It is so easy to incorporate a few native plant species into your garden, Traditionally it has been achieved either by creating a patch of meadow habitat or by planting a native hedgerow, but it is just as refreshing and interesting to simply include some native varieties amongst your ornamental borders and existing planting schemes or make a butterfly-buffet, raised bed or dot larval food-plant containers about.
If you want Brimstone (gonepteryx rhamni) adults to breed, you will need to plant their sole larval food plant Buckthorn (Rhamnus cathartica). The exquisite sulphur yellow Brimstones were original noted by some pioneering entomologists as the ‘Butter Coloured Fly’ and are the very source of the vernacular of Butterfly. If you want to support the Clouded Yellow (Colias croceus) then grow some clover (Trifolium spp) for it to lay its eggs upon.
Small Blue (cupido minimus) prefers Kidney Vetch (Anthyllis vulneraria) as its larval food plant while the Common Blue (polyommatus Icarus) utilises Birds Foot Trefoil (Lotus corniculatus) as its larval food plant. The young of the Dingy Skipper (erynnis tages) and Wood White (leptidia sinapis) feed on Birds foot Trefoil too.
The Holly Blue (celastrina argiolus) is more unusual in that, as its name suggests, it lays its eggs onto holly bushes (Ilex spp) in spring but come autumn it adapts and lays a second brood onto ivy, (Hedera helix). Ivy is a great choice to attract butterflies in general, as it is the best source of late nectar for many butterflies species and a place to overwinter for many that do.
So it doubles as a food supply to adult and young. Large Heath (coenonypha tullia), Small Heath (coenonympha pamphilus), Meadow Brown (Maniola jurtina), speckled Wood (Pararge aegeria), Wall Brown (Pararge megera), Graylings (hipparchia semele ) and Gatekeepers (Maniola tithonus) prefer their egg laying on common grasses.
That’s the wild grass that eventually takes over your lawn or colonises corners of the garden neglected enough to become a wildlife haven.
If ever there was a case for leaving a few nettles in your garden its The Small Tortoiseshell (aglias urticae) which lays its eggs on the undersides of nettle foliage. If you have a Buddleia or a Sedum in the garden you will already be enjoying the adults. Peacocks (inachis io) also require nettles to bred.
You won’t attract every butterfly as some are quite regional. For example the Brown Hairstreak (thecla betula) is confined to south Galway and north Clare where it lays eggs onto blackthorn (Prunus spinosa).
The Purple Hairstreak (quercusia quercus) sticks to well established oak woods Yet the Green Hairstreak (callophrys rubi) who favours gorse as a larval food plant, will find its way if you find a place to plant it.
Perhaps the rarest butterfly in Irelands is the Pearl Bordered Fritillary (boloria euphrosyne) found only in the Burren, Co. Clare.
Its cousin the Marsh Fritillary (eurodryas aurinia) will only breed in regions where Devil’s Bit Scabious grows and The Dark Green Fritillary (argynnis aglaja) often confines itself to coastal areas but it prefers Dog Violets (Viola reichenbachiana or Viola riviniana) as a larval food plant and you can lure it to your garden with such plants even if not on the shore line. Silver Washed Fritillary ( argynnis paphia) also feed on Dog Violets.
Orange Tip — anthocharis cardamines) preferencen Garlic Mustard (Alliaria petiolate) while the Painted Lady (Cynthia cardui ) choose Thistles (Cirsium spp) as their larval food plant. If you have dock or sorrel (rumex spp) then you can host Small Copper (lycaena phlaeas ).
Then there are three that we probably want to discourage the Green Veined White (pieris napi ), Small White — pieris rapae and Large White (pieris brassicae) each of which favour our brassica crops. You can always net the brassicas and plant out nasturtiums as a substitute.
Some other helpful items to make you garden butterfly friendly — avoid bird boxes which only house the main predators of caterpillars — birds.
Place some flat rocks in a sunny position as butterfly’s need some rest spots in full sun where they solar charge up.
Install some butterfly hotels for hibernation purposes and do place some water catchment about — be that a saucer or a water feature — they like a drink too.
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