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Post by nomad on Jun 12, 2016 7:49:53 GMT
Hymenoptera : The Sawfly Abia sericea
Sawflies are a primitive Hymenoptera of suborder Symphyta. The Sawflies have Caterpillar like larvae and in the UK there are as many as 500 different species making identification especially difficult. I found this colourful species, the local Abia sericea (Linnaeus 1767) family: Cimbicidae, flying and resting on nettles on chalk Downland in Wiltshire. The larvae feed on Devil's-bit Scabious, Succisa pratensis, which is also the foodplant of Euphydryas aurinia and the Narrow-bordered Bee Hawk-moth, Hemaris tityus in these grasslands. During my first visit to this downland I found one male of Abia sericea on a warm sunny day. I returned a week later to look for the fat bodied female and I had almost given up when I noticed one low down on a nettle stem and then crawling up to bask on a leaf, I tried to get a better image but disturbed she flew off before I could get a good shot.  Male Abia sericea. North Wiltshire Downs, May 2016.  Female Abia sericea, North Wiltshire Downs, June 2016.  The biotope of Abia sericea.
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Post by isidro on Jun 12, 2016 14:24:35 GMT
Splendid and very well photographed! During many years, Abia sericea was one of my most extremely wished species of hymenopterans, until a couple of years ago I've got Abia fulgens, that is almost identical.
What a biotope! :? Looks like incredible that any kind of insect can really live here.
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Post by wollastoni on Jun 12, 2016 16:37:53 GMT
Interesting sawfly species, I have never met this one ! Love it !
Below an example of sawfly caterpillar-like larvaes : 
Arge pagana on rose in Brittany
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Post by Adam Cotton on Jun 12, 2016 17:20:02 GMT
Looks like there's a parasitoid about to attack the top larva!
Adam.
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Post by nomad on Jun 12, 2016 18:05:57 GMT
Splendid and very well photographed! During many years, Abia sericea was one of my most extremely wished species of hymenopterans, until a couple of years ago I've got Abia fulgens, that is almost identical. What a biotope! :? Looks like incredible that any kind of insect can really live here. Thank you. This Downland NNR has a marvellous array of butterflies and other insects. My find of Abia sericea was around nettle patches that grew around rabbit burrows. I agree a spectacular insect and I was particularly pleased with the unusual male photograph. Nice that you was able to find the closely allied Abia fulgens. |
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Post by isidro on Jun 12, 2016 19:13:14 GMT
yes Adam, there is a pteromalid wasp. Looks like larvae of Arge rosae! nomad: as I only see shortly cuted grass in enormous extension, I just didn't imagine any nettle patch nor rabbit hole here! Near the forest of the background for sure there will be much more things  |
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Post by nomad on Jun 12, 2016 19:25:48 GMT
The nettle patches are out of view to the right and lower down the steep slope, the foodplant of the Sawfly is everywhere on this down. That's not a forest on top but a few Hawthorns |
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Post by nomad on Jun 12, 2016 19:34:33 GMT
Here is another view of the Downland-biotope looking back with the nettles included, top and bottom of the gully.  |
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Post by wollastoni on Jun 13, 2016 13:29:16 GMT
Looks like there's a parasitoid about to attack the top larva! Yes Adam. I wonder if the strange position of the caterpillars on the picture is normal, or if it is a "defense" position due to the presence of this parasitic wasp. |
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Post by wollastoni on Jun 13, 2016 13:30:58 GMT
Looks like larvae of Arge rosae! Could be. The identification was given to me by another entomo. I have no clue about those insects.  Hostplant was rose tree. |
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Post by nomad on Jun 13, 2016 14:19:58 GMT
Web site pictures seem to show Arge larvae feeding like this, I have no idea why. Lucky to get the Parasitic Wasp as well. |
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Post by wollastoni on Jun 13, 2016 15:04:59 GMT
I got many Pieris rapae caterpillars on my terrace in Milano last summer, all of them surrounded by 4 or 5 of these tiny black wasps.
It seemed to me that those wasps attacked only final instars of these Pieris rapae (just before they go pupating).
There were so many wasps for each caterpillars, I don't know if any of the butterflies have survived.
On the Arge larvaes picture though, the wasps seem to attack before the final instar.
If anyone knows more about those small black parasitic wasps behaviour, I would be interested to know more.
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Post by Adam Cotton on Jun 13, 2016 17:11:22 GMT
I'm not sure about sawfly parasitoids, but the ones that attack Pieris wait for them to pupate, and then lay eggs in the pupa just after the pre-pupa moults and while the skin is still soft. They can't actually lay eggs in the larva until it sheds its skin to pupate.
Adam.
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Post by wollastoni on Jun 13, 2016 17:30:26 GMT
Thanks Adam, it totally confirms what I observed on my terrace ! It seems the wasps have an ability to recognize pre-pupating larvaes ! Nature is incredible ! Especially in the insect world ! If only humans could spend more time admiring nature ... |
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