Four For Dinner

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.

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Rear garden, Staffordshire, England. July 2017.

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More Devastation

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.