Figwort El Dorado Spring 2010. THE FIGWORT WEEVIL.
After eight years I hit Cionus 'pay dirt'!
I'd noticed Cionus scrophulariae on Thames Buddleja here,opposite Kew Gardens for eight years,with no result,but,on 21/5/10 there was an explosion of 200 mating on Thames Figwort the other side of Kew Bridge;for next 6 weeks only 20 seen,then 110,not mating on 21/7/10,which must be the new generation.
which strongly indicates one generation/year.
Beetles emerging in August & September may be a small second generation.
Cocooning' (A Figwort branch,pushed in the earth,rooted & flowered!)
Microscope observation on larvae fron my patio Figwort & vivarium showed that Cionus doesn't spin it's cocoon - It grows on their skin & they re-enforce it from the inside,taking globules of fluid from their rear ends by mouth.
Camouflage. Alice in Wonderland Evolutionary camouflage!
Cocoons said to be camouflage resembling the Figwort seed pods,but this is a myth since they appear under the leaves early Spring whilst the seed pods appear late Summer;in dead Winter florets it looks like camouflage.An unfathomable,convoluted example of failed evolutionary camouflage!
Their is very heavy parasitism of Cionus larvae by wasps Entedon zanara & E.cionobius;of 22 cocoons 21 had 9 wasp larvae & pupae each in them!
Cionus in the field.
This Spring I walked 50 miles in 6 weeks on 24 excursions seeking Figwort in damp places;Only C.scrophulariae was found in ten kilometre square TQ 17.('Hounslow')
I walked for four weeks before a second species of Cionus was found!
Two other species were found @:-
Bedfont Lakes Reserve TQ 078 727.
C.alauda & C.tuberculosus.
Bushy Park ,Triss's Pond. TQ 155 606
Kennet & Avon Canal,Thatcham,Berks. SU 503 664.
C.tuberculosus & C.alauda('Funny little snowball with dark spot!)
WWT Barnes TQ 229 768
C.tuberculosus found/No figwort found @ Wimbledon Common,Rainham Marshes,Essex/Richmond Park.