Damien Enright: An hour spent on the dunes is well rewarded

The axiom that nothing in nature is wasted is reinforced on an outing to the coast
Damien Enright: An hour spent on the dunes is well rewarded
Two six-spot burnet moths sipping the nectar of a purple orchid in a west Cork salt-marsh in July. The moth caterpillars derive cyanide from their birdsfoot trefoil footplant and the moths' colours warn off predators. Picture: Damien Enright

On the last Sunday in July, walking the salt marsh behind the dunes at a beach in West Cork, I came across the arresting sight of two cyanide-laced moths sipping nectar from a gorgeous orchid. The orchid was an Early Purple orchid flowering late in season and the moths were Six-Spot Burnets.

I have no doubt about the identity of the moths, but the orchid is more difficult as the photos don't reveal the number of lobes of the flowerets. Anyway, there were many of these orchids, on tall stems, standing upright, heads pointing skyward. And attached to one were these toxic moths.

The red spots on the burnets' wings warn predators that the species is foul-tasting and toxic. Burnet caterpillars feed on birdsfoot trefoil, common on grasslands. As they feed on the leaves, they metabolise the toxins within their bodies without being harmed. If they don't get enough hydrogen cyanide from the plant, they produce it themselves. At the mating season, plumes of cyanide, combined with pheromones, are emitted by the females to attract the males. The males transfer cyanide to the females as they mate.

Cinnabars, another black-and-red day-flying moth species may be mistaken for burnets, but they have broader wings, slate-black, with red forewings above. Where ragwort thrives, the cinnabar's black-and-yellow caterpillars will be seen devouring the plant's yellow flowerheads. 

Ragwort, although it supports many insect species, is invasive and destructive to grassland. It is poisonous to horses, damaging their livers, often fatally. Farmers failing to control it can be fined. So effective are cinnabar caterpillars in the  biocontrol of ragwort, that the moth species was deliberately introduced into North America, Australia and New Zealand. Cinnabar, like burnets, are poisonous and contain alkaloids that make them bitter tasting. 

Once tried, forever shied. In dune and salt-marsh systems, there is much that is beautiful and curious to see. Certainly, the axiom that nothing in nature is wasted is reinforced, and an hour's expedition is well rewarded.

The other Sunday, as I walked, a couple of larks climbed the sky and  drenched the earth below, and my head, with song. The grasses thriving on the same earth would seem useless to humans but the banded snails and petite gris — the brown garden snail which the French eat, although they prefer the larger escargot — alone or clustered on the stems, are favourite fare for seashore dwellers and Pyrenean shepherds.

So close to the sea, the petite gris may well come ready-salted, and their shells are often pale, as if bleached. Thin layers of calcium add to the shell lip as the snail grows. 

Ireland holds over 100 species of land snail, but we don't eat any. Some are very colourful, especially the yellow snail with dark brown stripes of the dunes. While thrushes are mainly carnivorous and eat snails, blackbirds favour fruit and — I've lately discovered — are capable of reading the significance of human actions and foreseeing the future result.

File image.
File image.

Last week, I started putting netting around a gooseberry bush in our garden laden with purple berries not yet quite ripe, but soon to be. As darkness came on, I left the work half finished. Two days later when I came to complete it, the bush was bare. The blackbirds (and perhaps the magpies) had guessed my intent and decided to strike while they still had access.

Wildlife has an uncanny ability to recognise  danger signs, like the red spots on burnets, and a sixth sense that tells them when they are being watched, even if one is a long distance away.

At the salt-marsh, bumblebees were busy sipping the nectar in the orchids and in the flowers of sea lavender. Some 80% of wild bees are bumblebees, and they do more pollinating than honey bees. Ireland has 14 species of true bumblebees and six  species of cuckoo bumblebees. The latter, like feathered cuckoos, lay in other species nests and leave the hosts to rear the babies. My brother, who has a great number of almond trees on his land in Spain bought hives of bees to pollinate the trees. Last year, the crop was enormous. Not so, this year; the trees are resting. Meanwhile, thieves stole 15 of the hives, bees and all.

Insecticides having killed off billions of bees, in the United States the renting of working hives to fruit farmers at a pay-by-the-day rate is big business. Hives are transported farm-to-farm around the country.

Meanwhile, in California, the useful medical properties of marijuana extracts having been discovered and licensed, one commercial farm alone comprises 147 acres of grow tunnels. Old time, pot-head artisan growers cannot compete.

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