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24/01/2015

 
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Jaybee



Joined: 21 Jun 2013
Posts: 866
Location: Durham

PostPosted: Sat Jan 24, 2015 7:49 pm    Post subject: 24/01/2015 Reply with quote

Bright sunshine today and not as cold as it has been so a 5 hour visit to a local patch NZ 44370 42273 looking for anything that moved really.
Nothing in the vegetation at all but quite large numbers of Orange ladybirds on a very select few saplings. Two 7-spot ladybirds - one on gorse the other on a dry teasel head.
Into the small wood to look through rotten logs etc for millipedes, grubs etc.
One large rotten stump gave up it's treasure in the form of a tree bumblebee and my first hovers of the year (In a manner of speaking).
Digging into the stump I found dozens if not hundreds of dead hoverflies comprising of mostly E. balteatus but other species were in amongst them which someone might recognize.
I'm sure this isn't of use to the HRS but I thought it had interest.
The hovers were in groups and seemed to be purposefully lining bore holes in the rotten wood. Alongside the masses of hovers were lots of cocoons which looked far to big to be the result of hoverfly laying.
One grub was out of it's cocoon.
I suppose finding out what species the grub/cocoons were would throw light on what had apparently predated the hovers and buried them alongside their eggs for a meal when the grubs hatched (If that was the purpose).
Photos below.

First the cocoons/grub







This was a much smaller cocoon



Hoverfly detritus

















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Brian & Stephanie Lit



Joined: 14 Apr 2006
Posts: 10
Location: Fife

PostPosted: Thu Feb 19, 2015 9:48 am    Post subject: Reply with quote

Jaybee,

a fascinating set of photos. I suspect you'll have three species here. The clusters of Syrphid adults suggest to me these are cells of one of the hunting wasps, Ectemnius that collect flies as larval food and nest in dead wood - the most likely would be E cavifrons. I've no idea if it over winters as a a pre-pupae (your grub) or as a pupae, in your cocoons. You'd have to rear them through. If it does over winter as a pre-pupae then the cocoons are most likely parasitoids, and vice versa if it over winters as a pupae then the grub will be a parasitoid. The shiny red pupal case is likely to be a dipteran. I can advise on rearing through if required. It would be a excellent set of records, either way great photos.

Brian.
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Brian & Stephanie Lit



Joined: 14 Apr 2006
Posts: 10
Location: Fife

PostPosted: Thu Feb 19, 2015 9:52 am    Post subject: Reply with quote

Jaybee,

a fascinating set of photos. I suspect you'll have three species here. The clusters of Syrphid adults suggest to me these are cells of one of the hunting wasps, Ectemnius that collect flies as larval food and nest in dead wood - the most likely would be E cavifrons. I've no idea if it over winters as a a pre-pupae (your grub) or as a pupae, in your cocoons. You'd have to rear them through. If it does over winter as a pre-pupae then the cocoons are most likely parasitoids, and vice versa if it over winters as a pupae then the grub will be a parasitoid. The shiny red pupal case is likely to be a dipteran. I can advise on rearing through if required. It would be a excellent set of records, either way great photos.

Brian.
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