Creepy Crawlies

Creepy Crawlies 

Creepy crawlies are an essential part of the wildlife of our gardens. To appreciate them we need to know a bit about them and the role they play in the world around us, says Eanna Ní Lamhna.

All the animals in the world can be divided into two groups. There are those with backbones, which are the birds, mammals, reptiles, fish and amphibians. All the rest are in the other group, those with no backbones, and their official title is invertebrates. These include all the insects and the spiders and the earthworms and snails and woodlice… what I refer to as creepy crawlies. And whether you like them or hate them or are afraid of them, one thing is certain; we could not exist without them. Indeed, there are more species of insects on earth than all the rest of the animal species put together, and they all play a very important role in our ecosystems. 

Pollinators

Take bees for example. These are particularly important because they are our main pollinators. Pollinating insects visit flowers in order to get a drink of nectar, treating them like mini pubs really. The nectar is buried deep in the flower and, to get to it, the insect must stick its head right in. The pollen on the flower’s anthers brushes on to its head. When the insect visits the next flower for more lovely drink, the pollen from the last flower brushes off the female part of the flower. Hey presto, the plant is pollinated. Fruits and seeds can begin to form. All our fruit and many of our vegetables rely on this process.

Lots of insects as well as bees, such as butterflies, wasps, hoverflies and drone flies, visit flowers for nectar, but only bees actually collect pollen in pollen baskets on their back legs and bring it back to feed their young.

Finding a mate

Butterflies visit flowers too. They treat them as singles bars where they go to pick up a mate while sipping a nectar cocktail. All the food a butterfly gets in its life is consumed during the caterpillar stage when they eat voraciously – as we know to our cost, looking at our ravaged cabbage leaves after the cabbage white butterfly has deposited her eggs there. But once the caterpillar turns into a butterfly, it is a different creature altogether. It has no stomach, no guts and it never does a poo. All the energy it spends as an adult was acquired during the caterpillar stage. But it can sip nectar and it visits nectar-rich flowers in our gardens, such as Buddleia for a drink. There it happens upon other adults with whom it can mate, and the female then goes off to lay eggs on its particular food plant and then die. The males probably find another few mates, before they too run out of energy and die.

Ladybirds

Ladybirds on the other hand are carnivores and they spend their lives looking for greenflies and aphids which they can devour. They belong to the beetle group and they can fly on transparent back wings that they keep hidden under coloured hard front wing covers when at rest. We have twenty different species in Ireland, and they are not all red species either. As well as the common seven-spot red ladybird, we have yellow ones with black spots, black ones with red spots and red ones with cream spots. We even have a spotless species too. Lately however, an invasive species called the harlequin ladybird has been introduced to Ireland and it eats the young of other ladybirds and so is an unwanted pest. They have a lovely name in Irish – Bóinn Dé – which means God’s little cow. A bundle of bamboo sticks tied together and left in the garden near the hedge can act as hibernating quarters for them in wintertime.

Why wasps?

The wasp is a much-maligned insect. It actually doesn’t spend its time going around looking for humans to sting (more than once if it can). The life cycle of the wasp plays a very important role in our natural community. Wasps are social insects – like bees – and live in a nest with a queen. In April, the queen wakes from hibernation and starts to build her paper nest and found her colony. All the eggs she lays, hatch out into female worker wasps. Their job is to mind the nest and feed the young wasp larvae that the queen continues to produce. These larvae are carnivores, so all summer long, the worker wasps comb your garden collecting aphids, greenflies, whiteflies and blackflies to bring home to feed the young. These are all pests that otherwise would be sucking the life out of your roses and destroying your lupins. In the autumn when the old queen dies off and there are no more young to feed, wasps can become a pest as they are looking for sugary things to feed on themselves. They find a lot of this in the nectar of flowers and on fallen fruit, but they may come into houses then and annoy people too. By the end of October, they are all dead, the nest is empty, next year’s queen is in hibernation waiting for spring so that she can emerge and start the cycle again – in a new nest that she builds from scratch. Last year’s nests are never re-used. Wasps make a huge difference, keeping the number of sucking aphids down in their natural environment.

Spiders

Spiders are not insects – they have eight legs and they cannot fly. They belong to a different group altogether and we have about sixty different species in Ireland. They are all carnivores. Some of them are web-spinning spiders who catch their prey in elaborately-spun webs, while others are hunting spiders that come out at night to chase and catch their dinner. They all have fangs – sharp hollow teeth which they sink into their trapped prey and through them inject the venom that quickly kills the hapless fly. Except for the recently arrived false widow spider, none of the rest of them have fangs strong enough to bite us. If you want dangerous spiders, Australia is the place to go. They form a very important part of the food chain here, eating huge quantities of annoying insects and in turn being eaten by robins, hedgehogs, frogs and indeed bigger spiders, because spiders are not just carnivores – they are cannibals.

Woodlice

Woodlice are not insects either, they have 14 legs and a hard segmented body. They are the dustbin men of the garden and woodland. They feed on dead plant material such as dead leaves. By doing this, they break them down and release all the mineral nutrients back into the soil for other plants to grow. They, in turn, are eaten by spiders, pygmy shrews, hedgehogs and any bird that is sharp-eyed enough to spot them. They feed at night and spend the day sheltering under flowerpots or behind loose bark so that the heat of the sun won’t dry them out. The nerve of us to say that we don’t like the look of them. I am sure the woodlice don’t like the look of us either, and with good reason.

Earthworms

Earthworms are dustbin men too. They live in the soil and feed on the dead plant particles there. In order to do this, they eat large quantities of soil and digest the plant material as it passes through their body. Thus, they aerate the soil with their tunnels as well as ensuring that the mineral nutrients of the soil are replenished. Really good fertile soil has millions of earthworms working away unseen underground. Farming and gardening would be next to impossible without them. They are blind, as they have no need to be able to see to get their food. They are also all hermaphrodites which means that they have both male and female organs – but they must meet and mate with another worm before they reproduce. They form 40% of the diet of badgers and rooks, jackdaws and blackbirds are expert at finding them in lawns and grassy fields, dragging them up with their sharp bills.

Snails

Snails are hermaphrodites too, which probably explains why there are so many of hem. Each and every one can lay up to a hundred eggs after mating with another willing snail. Gardeners are not a bit fond of these are they are rampant herbivores and can inflict a lot of damage on prize plants and emerging seedlings in the space of one night. However, it is really important that we DO NOT put out poisons for them in the form of little blue pellets. This not only poisons the snails, but also all the creatures higher up the food chain that feed on them. Thrushes are able to eat snails, they have worked out how to bash them open on stones. If they eat poisoned snails, the toxins build up inside them and they die too. Our thrush numbers in Ireland are declining and eating poisoned snails is the main reason. If you must get rid of them, go out at night when the snails are hard at work demolishing your plants and collect them with the aid of a torch light. A quick snip with a scissors and the thrush’s breakfast of nice, unpoisoned snails is assured.