Sunday 3 July 2016

Blaencaerau tips and fields

Had another 3 Forester today all looked fresh and pristine about 300 yds from my earlier 2 sightings. Amongst the butterflies were 40 Ringlet and 18 Dark Green Fritillary. There was a huge explosion of Burnets today maybe over 500. The trouble is I can't tell the difference between NB5SB and 5SB. I read online that NB5SB antennae are widest at 14th segment from tip and 5SB  are widest from 9th segment from tip, plus the subtle difference in wing shape. I photographed both. The 5 spot's [9th segment widest] were well spread out over the reclaimed tips and numbered about 200. However the burnets with the 14th segment widest were all in one small field about 100yds by 50yds and there were maybe 300 of them in this small area. Below are 2 photos of what I think are 5 -spot and 3 of what I think are NB5SB. Can anybody shed any light onto the photographs as to which species is which.


  1. The only reliable method I know is to find recently mated pairs sitting adjacent to cocoons, and collect the shed larval skins from the cocoons - long hairs = NB5S, short hairs = 5S.

    I've not heard about this antennal feature though.

  2. Thanks Dave, I'll check the skins as there were plenty around at both sites. Here's the link to where I saw the antennae segments mentioned.