This video says about itself:
8 July 2015
Time-lapse movie of tiny parasitoid wasps (unidentified, family Braconidae?) emerging one by one from a cluster of cocoons which were made beside their host, a larva of Gypsy Moth (Lymantria dispar japonica, family Lymantriidae). The hairy caterpillar was still alive, barely. Apart from the parasitoid wasp, there was tiny maggot(s) of tachina fly growing inside the dying host. Early-June 2015 in Japan.
The room temperature was 23 degrees Celsius. The first part of timelapse movie was made from 10-sec interval shot. The eclosion started three days after collecting the specimen with a leaf of viny plant (unidentified) climbing a tree of Sawtooth Oak (Quercus acutissima, family Fagaceae). The tiny wasp turned out to be secondary parasitoid wasp (Acrolyta sp., family Icheumonidae).
From the RSPB in Britain:
Wasp species, new to the UK, discovered on a stroll to the car park
21 October 2015
It has taken two years to publish, but experts have concluded that a wasp caught in a chance sweep of a butterfly net at the RSPB’s Broadwater Warren nature reserve is a type of wasp never before recorded in the UK.
It was back in 2013 as Tony Davis of Butterfly Conservation was undertaking a moth monitoring programme at Broadwater Warren when he came across an ichneumon wasp specimen; a parasitic wasp, Lymantrichneumon disparis, now known to be a genus and species new to Britain.
Tony said: “I’d finished my work and was leaving the reserve but couldn’t resist one last sweep on my net and that’s when I found the wasp. I knew it was something special, but I could never have guessed it was an entirely new species to the country.”
Dr Gavin Broad is an expert on ichneumonid wasps, employed by the Natural History Museum. The specimen was sent to him for identification. It has no common name and no other specimen has yet been found.
Dr Broad believes the find was a recent colonist from continental Europe. He said: “It’s not uncommon to find parasitic wasps new to Britain, but to find a new genus for the country that is large and showy is very unusual and good evidence of change in our fauna. I knew almost immediately what this wasp was as I’d recently been looking at some Japanese specimens of Lymantrichneumon disparis. It was rather surprising to see one from Britain! Inevitably, it took me quite a while to publish on this.”
In Europe the wasp parasitises a few related moth species including the gypsy moth, which has recently colonised parts of southern England. It is possible that the arrival of the wasp is related to this gypsy moth colonisation. However, the wasps are known to parasitise native moths too, so its arrival could also be due to warming of the climate.
Broadwater Warren was acquired by the RSPB in 2007, when work started to remove ranks of conifers to restore the historically open landscape of the Weald and improve the surrounding woodland for wildlife. Lowland heath is now a rarer habitat than rainforest! Almost 80 per cent of the UK’s heathland has disappeared since the 1800s due to forestry, agriculture and urban development. This loss of habitat has been one of the contributing factors behind the decline of a number of native species.