Tag Archives: defence

Spit on the Foliage

Well, here I am once again examining some unusual phenomenon that appears in Wicklow in June, and can now be seen everywhere. What am I looking at?

A big shout out to Rosemary and Ken Curp in Ohio, and Catherine Curp in Texas - thanks for the cap!
A big shout out to my relatives Rosemary and Ken Curp in Ohio, and Kathleen Curp in Texas.

Anyhow, this strange phenomenon is the rather unpleasant-looking ‘spit’ that appears on the leaves of low-growing plants at this time of year:

Spit on the bushes - unpleasant to look at but a really fascinating phenomenon.
Spit on the bushes – unpleasant to look at but a really fascinating phenomenon.

This spit is known traditionally as ‘cuckoo-spit’ because it appears after the arrival of cuckoos. In modern times cuckoos are a lot less common that cuckoo-spit. If you want to solve the mystery you need to be a bit brave and run your fingers through it, revealing…

A strange little green bug in the middle of all the spit. What's it doing there?
A strange little green bug in the middle of all the spit. What’s it doing there?
The same little bug from a slightly different angle.
The same little bug from a slightly different angle.

This little bug is actually a species of insect known, appropriately, as ‘spittle bugs’. There are many species the most common being the so-called Froghopper, which somewhat resembles a miniature frog, and it really can hop, further than any frog I’ve seen. The larva is known as the Cuckoo-spit Aphid, which is actually a misnomer, as these bugs are not true aphids. The spittle is caused by the little bug sucking sap out of the plant it is living on and then blowing the sap out through its backside in the form of bubbles until it is completely enclosed in a shroud of bubbles which protect it from predators and parasites. But these bubbles might also distract potential predators, as I have seen quite a few creatures apparently feeding on the bubbles. Perhaps it tastes sweet like honeydew, which true aphids blow out of their butts as bubbles. The photo below was the first time I had ever witnessed a predatory insect feeding on the cuckoo-spit bubbles. But maybe it was trying to get at the little bug beneath…

A Seven-spot Ladybird feeding on bubbles. Perhaps Cuckoo-spit is a delicacy in the insect world.
A Seven-spot Ladybird feeding on bubbles. Perhaps Cuckoo-spit is a delicacy in the insect world.

 

Spit on the flowers…?

Right now Cuckoo-spit is appearing on the flowers of meadows and hedgerows. At first glance it looks like someone came along and spat on the plants, but on closer inspection it appears to be more like washing-up liquid foam.

A classic Cuckoo-spit I photographed today.
A classic Cuckoo-spit I photographed today. Note the greenfly aphid just above it on the leaf branching to the right.

And you might be thinking, because of its name, that Cuckoo-spit is the saliva of the cuckoo bird. It’s not, but get’s its name because you usually hear the cuckoo around the same time you begin seeing this “spittle”. It is in fact an elaborate defence mechanism of a tiny creature that lives beneath the Cuckoo-spit. This insect is known as the Cuckoo-spit Aphid, but is actually a juvenile Froghopper or Spittle-bug.

A Cuckoo-spit Aphid on my hand. They look somewhat like a strange type of childrens' toy of some sort.
A Cuckoo-spit Aphid on my hand. They look somewhat like a strange type of child’s toy.

This little insect cannot hop to escape predators like the adult bug, so instead it blows bubbles of water, from its backside. These rigid little bubbles cover it, but also allow air between them so that the nymph (juvenile bug) can breathe. A truly fascinating defence-mechanism.

There are several species ranging in size from a few millimetres to about 1.5 cm in length.

 

Wicklow’s Spring Biodiversity Explosion

As April draws to a close we have reached high Spring, and this year has been a superb one. The steady weather conditions and good levels of sunlight have transformed the landscape. The shrubs and trees are beginning to bloom, adding to those of the undergrowth. This year the lilac trees have been early and especially impressive due to the dryness – in wet years the fleshy, fragrant flower-spikes rot rapidly. This year they are the magnificent ornaments they are meant to be.

Lilac blooms - Syringa vulgaris

But the undergrowth is only really getting started. In woodlands, and on the narrow lanes of Wicklow you will find intoxicating seas of Ramsons (Allium ursinum), the wild garlic. Driving along these lanes with the car window rolled down can be something of an aromatic adventure in springtime.

Ramsons or Wild Garlic

The flowering plants depend on sunlight, and in turn the invertebrates, particularly insects, depend on the flowering plants to provide serious energy, in the form of nectar and pollen. Of course, the plants are equally dependent on the insects to fertilise them so there will be more plants, and insects, next year. Away from the trees the Daisy (Bellis perennis) are one of the most important nectar-producing species, supporting every conceiveable pollinating creature, and reaping the rewards. Wild meadows are very important habitats for this reason.

A Speckled Wood butterfly (Pararge aegeria) feeds on one of thousands of daisies in a small meadow.

As the length of days and exposure to sunlight increases the number of plant species in bloom greatly increases, which in turn supports more and more pollen and nectar-dependent organisms.

This, in turn, leads to an increase in predator numbers. One of the most interesting and unusual predators of other insects is the Yellow Dung-Fly. These flies are normally seen perched on cow dung in huge numbers, where they mate, lay eggs, and attack and eat other insects attracted to the dung. However, in spring they feed mostly on pollen, because there is so much of it about, and their prey numbers are still growing. The fly in the photo is covered in pollen, having clearly gorged, probably on daisies.

Yellow Dung-Fly (Scatophaga stercoraria)

Because of predators nectar and pollen-feeders have to be able to defend themselves: in spring you will see many species of bee, all armed with potent stings.

Bombus pascuorum is a distinct bumblebee species with a very long probing tongue, which allows it to fertilise many flowers no other insects can...it is vital to the environment. Here is is seen feeding on dandelion.
Nomada bees are small, solitary species that look very like wasps, but are extremely shy and best seen feeding on apple blossom. They are quite curious and will "people watch".
A female Mining Bee (Andrena haemorrhoa), a solitary species commonly seen in spring, where they build little tunnels in lawns and meadows, with small vocanic-looking cones around them. This species collects pollen on special hairs on its hind legs, as you can see in this photo.

However, many of the bees you will see in Wicklow are not bees at all. Instead of developing toxins, many species of fly have opted to imitate bees, and it is difficult even for naturalists to tell them apart. The trick is to look at the heads: the flies have large round heads with little or no fur, and they have only stubby antennae, whereas bees always have long antennae curling from their heads.

A brilliant white-tailed bumblebee-mimic hover-fly, Volucella bombylans, feeding on Alexanders.
A stunning hover-fly, Leucozona lucorum, also feeding on Alexanders by a roadside.

However, flowers do sometimes get more than they bargained for, slugs will also happily eat pollen, and the entire flowerhead. But only very, very slowly, and very occasionally.

A beautifully-patterned Common Garden Slug (Arion distinctus), feeding on dandelion pollen.

Thanks to the abundance of nectar many insects can take time off to find mates and breed, something that would be impossible to do if they didn’t make a profit when it comes to feeding. The beautiful little Orange-tip butterflies are only with us for about four or five more weeks, so watch out for them in gardens, along roads and flower-filled meadows with good hedgerows. They are now taking the time to find mates and breed, and the sight of a pair of them dancing over hedges is a strong sign you will very soon witness a marvellous event: I saw Orange-tips mating for the first time in my life this week. They are so common at this time of year, it is strange how well they hide their social lives. Maybe they’re marvellous camouflage prevents the casual observer from noticing. However, I’m not a casual observer, so it is rare: if you do witness this event you are one of a lucky few.

A mating pair of Orange-tip butterflies perched on sedge. The male is the right way up.