Can’t See The Wood For The Trees? … What About The Leaves?

x8 images. Double click to enlarge.

Stigmella aurella found on Bramble

It was a fellow blogger Sconzani who runs a wonderful blog with the lovely tiltle Earthstar ~ a celebration of nature who got me looking much more closely at the leaves on not only the trees, but most anything else which has leaves.

Horse Chestnut Leaf-miner Cameraria ohridella larvae leaf-mines
Cameraria ohridella on Horse Chestnut

Leafminers can be from different insect groups. Many species of Lepidoptera (moths), Diptera (trues flies), Coleoptera (beetles) and Symphyta (sawflies), have larvae which mine plants. It is the larvae of these insects which produce these mines within the leaves of plants, feeding on the plants’ tissues as part of their development cycle.

Stigmella microtheriella on Hazel

Mines tend to be restricted to a certain range of host plants and so the identification of a miner is facilitated by correctly identifying these plants. The shape of the mines (gallery or blotch) and the patterns of the droppings (frass), besides characteristics of the larvae and pupae, can be diagnostic. Even the location of where the egg is layed on a leaf can be diagnostic and can help to separate similar species.

Phytomyza ilicis

The Holly Leaf Miner (above image) forms quite a wide gallery on Holly (Ilex), and is only one of two holly leaf miners to be found in the wholes of Europe, and the only one to be found in the UK. The adult female Agromyzid fly Phytomyza ilicis lays its eggs in May or June at the base of the petiole of a young leaf (on the underside). The oviposition scars can be seen on the midrib on the underside of the leaf. The larva initially feeds in the mid-rib, later producing the characteristic irregular upper surface linear-blotch.

Phytoliriomyza melampyga

The fly Phytoliriomyza melampyga mines the leaves of Impatiens species (Balsams). Here it was found on Himalayan Balsam (Impatiens glandulifera), an invasive plant species here.

Lyonetia clerkella on Wild Cherry

The larva of the micro-moth the Apple Leaf-miner (Lyonetia clerkella) feeds on a variety of Rosaceae (rose family) and Betula (birch) trees in small, long and winding leafmines.

Profenusa pygmaea on English Oak

The larva of the sawfly Profenusa pygmaea mine the leaves of various species of oak (Quercus) creating a large blister or blotch mine on the upper surface.

Stigmella microtheriella on Hazel

So next time you are out in the woods … or even in the park or garden … take a closer look at those leaves and see what squiggly patterns or blotches have been created within them.

Check Your Roses

Large Rose Sawfly (Arge pagana)

If you check your roses now you might find these gregariously chomping away on the leaves. It is possibly one of 2 species of sawfly Arge pagana or Arge ochropus, and it is hard to tell which in the early instar stage. But if you can find the original egg scar on the stem you will know what species it is for sure. If it has a double row of cells it is Arge pagana, and a single row determines Arge ochropus. From my own past experience, unless you get a whole army of these chomping larvae they won’t seriously damage your rose. Sometimes the birds will grab them for protein.

Large Rose Sawfly Arge pagana larvae

Large Rose Sawfly Arge pagana larvae

Large Rose Sawfly Arge pagana egg scar

Reed Stem Borer

Calameuta filiformis – This is one of the sawflies, which are a fascinating group of insects and are related to the bees, wasps and ants of the order Hymenoptera. They are of a suborder called Symphyta. Sawflies do not sting, despite how ferocious some of them may look, and can sometimes be easily overlooked as wasps. The larva of this species feeds on various grasses and reeds.

Reed Stem Borer Calameuta filiformis female
Reed Stem Borer Calameuta filiformis female

Double-click images for a closer look.

Turnip Sawfly

Athalia rosae – I see a lot of these brightly coloured sawflies in the garden. They enjoy their leisure time and spend a lot of it just sitting about on lush green leaves in the flowerbeds. They grow up to around 8mm (5/16in) long, and love feeding on nectar from a range of flowers. The larva feeds on cruciferous plants where it can be a pest. Double-click the images if you wanna get closer.

Turnip Sawfly Athalia rosae

Turnip Sawfly Athalia rosae

Turnip Sawfly Athalia rosae

Copyright: Peter Hillman
Camera used: Nikon D7200
Date taken: 20th June 2019
Place: Rear garden, Staffordshire

Pod People In My Hawthorn Bush

Social Pear Sawfly Neurotoma saltuum larvae

This isn’t one for the squeamish. Not quite ‘Pod People’ – hawthorn would hardly make a comfy bed for them to mature in. It was a beautiful early morning, and I was admiring the roses when I caught site of this large sprawling web between my hawthorn bush and climbing roses. The light was filtering through the neighbour’s cherry tree so I could not quite make out what I was seeing at first. I thought, gosh there must be some big spider in there somewhere. But I could not see the wood for the trees, as they say.

Social Pear Sawfly Neurotoma saltuum larvae

And then I saw a wriggling, teeming mass of squirminess (I don’t even know if that is a word or not?). I was both revolted and fascinated at first. What an earth were they? Never mind that, I needed to get my camera. The first image shows it as how I first saw the web in the partial shade, which is kind of creepy, and I was creeped out at first to be sure. With the others images I upped the ISO a little to get more detail.

Social Pear Sawfly Neurotoma saltuum larvae

At first I though they were Ermine caterpillars/larvae, as they form masses of silken webs on vegetation. Yet they didn’t look like caterpillars of any moth. I discovered they are actually Social Pear Sawfly (Neurotoma saltuum) larvae, which not only feed on pear, but also apple and hawthorn and cotoneaster, amongst other trees and shrubs. The web must protect them from predation, for wherever they go the web is there with them.

Social Pear Sawfly Neurotoma saltuum larvae

They appear to be stripping the leaves off the bush within the webbing. Since these photos were taken a few days ago the mass has split into two opposing groups going in opposite directions on the bush. Despite their rampant appetite, the trees are not usually permanently harmed. The larvae will reach a length of 25mm (1in) when fully grown, and then they will go down into the soil to pupate. In the following spring the black coloured adult sawflies will emerge.

Social Pear Sawfly Neurotoma saltuum larvae

Click once to expand view, click again to get that little bit closer

July 2018, rear garden, Staffordshire, England. © Pete Hillman.

Athalia cordata

Athalia cordata

This is quite a brightly coloured sawfly which I often see in my garden during the spring and summer months. They grow up to 7mm (0.3in) long, and are seen around the plant Bugle Ajuga reptans, which is one of the plants the larvae feed on. The commonest of the Athalia and widespread in Britain. Often seen in gardens.

Double click on images to enlarge.

August 2017, rear garden, Staffordshire, England.

Last One Standing

Large Rose Sawfly Arge pagana larva

Or maybe I should I titled this blog ‘Last One Munching’. I have been watching these Large Rose Sawfly (Arge pagana) larvae for the past few days, and how they have chobbled on my rose leaves and how they have grown fat on them. This is the final instar stage and the others had dropped off the leaf into the garden border to pupate, and this was the last remaining one, still merrily chomping away. This was yesterday afternoon. This afternoon it had gone, too. Below are some images I took a few days earlier.

Large Rose Sawfly Arge pagana larva

I couldn’t believe that with all those rose-bush leaves they were all trying to nibble on what little was left of this one.

Large Rose Sawfly Arge pagana larva

September 2017, rear garden, Staffordshire, England.

Four For Dinner

Large Rose Sawfly Arge pagana larva

They have been at my roses all summer so far, and they are certainly making a meal of them. These are Large Rose Sawfly (Arge pagana) larva, young instars most likely. And four of them seem to like this one particular leaf for some reason. I feel sorry for the top two, for when they finally meet in the middle it will be the guy sitting on the branch he is sawing off scenario. Or maybe it won’t come to that.

Rear garden, Staffordshire, England. July 2017.

Please click on an image for a larger more detailed view. Clicking a second time may get you a little closer.

Turnip Sawfly

Athalia rosae

Turnip Sawfly Athalia rosae

This is quite a small but very distinctive sawfly which I regularly see around my back garden. Brightly orange body and legs, a black head, black markings on the thorax and along one side of the wings.

Turnip Sawfly Athalia rosae

Common and widespread, the larvae are considered to be an occasional but serious pest of crucifers, especially turnips.

Turnip Sawfly (Athalia rosae), rear garden, Staffordshire, England. May 2017.

Tenthredo maculata

Tenthredo maculata

This sawfly is a striking yellow wasp mimic, with a large bright yellow band across its abdomen, which is larger in the males. It also has yellow markings on the thorax, head and legs. Dark patches on wing margins. Length 12 to 16mm.

Tenthredo maculata

The larvae feed on grasses.

Tenthredo maculata

It flies May to late summer, and it is found along hedgerows and woodland rides, and in meadows where they maybe seen feeding and mating on umbelliferous flowers. A common and widespread species, except for the far north.

Photographs of Tenthredo maculata, taken June  2013, local woodland path, Staffordshire. © Pete Hillman 2013. Camera used Nikon Coolpix P500.

More Devastation

Large Rose Sawfly (Arge pagana)

They are at it again. I have posted on these previously this year, and these sawfly larvae, called Large Rose Sawfly (Arge pagana), are stripping my rose-bush leaves again. They seem to be very methodical in their consumption of the leaves, completely stripping individual leaves bare before moving onto others, leaving ravaged skeleton stalks behind them. They must be another generation.

But if the little birds catch site of them, they are a good source of protein.

Please see my previous posts ‘Balancing Act’ and ‘Life In A Week’ for more information.

Photograph of Large Rose Sawfly (Arge pagana), taken August 2016, rear garden , Staffordshire. © Pete Hillman 2016. Camera used Nikon D7200, with Sigma 105mm macro lens with softbox flash diffuser.

Life In A Week

It’s amazing how things can change in just one week, especially if you are an insect. Last week I posted ‘Balancing Act’, which showed these caterpillars in an early stage of development, and after one week of almost continuous feasting on my rose-bush leaves how they have grown and changed.

These are Large Rose Sawfly (Arge pagana) larvae, and how bright yellow and distinctly marked they have become within just a short period of time. They can grow up to 25mm in length. By the end of this month they will have dropped from the rose leaves to bury themselves in the earth. Pupation will take place in a very short time, and at the start of August the brightly yellow coloured adults will emerge to begin the cycle over again.

Balancing Act

Large Rose Sawfly (Arge pagana) larvae

Another species of sawfly on my roses, and I believe these may only be young instars. There are two species of large rose sawfly in Britain, this species being the more common of the two, the other being Arge ochropus. Sawfly have good balancing skills, and to ward off predators they jerk their tail ends around in the air.

The adults, which I have seen flying around the garden, are quite distinctive and have bright yellow abdomens. The female makes a tiny saw cut in plant tissue in which she will lay her eggs. The resulting caterpillars will feed in groups, and they can strip leaves quite rapidly if in large numbers.

Two to three generations of Large Rose Sawfly maybe produced from May to October. They are seen in parks and gardens, also hedgerows, anywhere where rose occurs. Common and widespread.

Photographs taken July 2016, rear garden, Staffordshire.

Rose Ravagers

Whilst deadheading some roses in the garden, I came across these happy pair which had virtually munched their way through a whole rose-leaf. It is called Arge nigripes.

Notice how the one has it back-end in the end. This is a tell-tale sign that these are not your normal moth or butterfly caterpillar, but the larva of a species of sawfly. If disturbed they will whip their tails around to ward off predation, sometimes spraying a foul chemical. Another way to tell is that they have six or more prolegs, a few more than their lepidopteran friends.

They are quite gregarious creatures, so I guess I am fortunate to just have the two of them, as far as I could see. Although I did spot a bunch of other sawfly larvae shortly after, rapidly consuming fresh rose shoots, but that’s another story.

This one here is almost quite cute as he hugs the leaf and almost appears to smile …

In large numbers sawfly larvae can become a serious pest, but thankfully they appear to be doing but a little harm to my roses. And when viewed from above it has quite beautiful pale and dark green stripes running the length of it, and a darkish brown stripe on its head.

Sawflies belong to the order of insects called Hymenoptera, same as the bees, wasps and ants. Adult sawflies are harmless and do not sting. The females cut through plant tissue to lay their eggs inside. And the result are these hungry caterpillars.

Photographs taken July 2016, on rose-bush, rear garden, Staffordshire.