Fifth Garden Clearwing sps

I put out my HOR and VES lures this morning at 9.30am in my garden at Beenham, Berks. Between 10.00 and 11.00am I had another Hornet Moth to HOR and 3 Orange-tailed Clearwings to VES. Interestingly one of the OTCWs was much smaller (about 50%) than the other two (see second picture).

Perhaps this reflects a one versus two year life-cycle or natural variation in feeding success?
(This influx of Clearwing species is getting ridiculous - FOR and HYL lures out now. I'm thinking of getting the garden designated as an SSSI (especially as it would mean that I wouldn't be allowed to do anymore weeding - great). Either that or someone down the road is releasing these sps by sps on a daily basis!)

Derek