AlanS's picture

Moths, lichens, distribution change?

As a botanist/mycologist/lichenologist it's not often I set foot (tarsus?) in this forum, but I was admiring the photographs of the Merveille du Jour moth at http://www.ispotnature.org/node/376400

The poster (orchid_b) mentioned the lichens the moth was on, and I added a comment on their identity. But this set me thinking:

a) the patterning on the Merveille du Jour was a remarkable match to the lichen it was resting on (Parmelia sulcata). So much so that I wonder if it preferentially rests on this common species?

b) if it does preferentially rest on Parmelia saxatilis, is it now being affected by the spread of nitrogen-tolerant lichen species, notably the bright orange Xanthoria parietina? Over substantial parts of lowland Britain, Xanthoria is ousting other lichens, the spread being attributed to nitrogen/ammonium compounds in agrochemicals and traffic fumes.

While still generally common, there can be little doubt that Parmelia sulcata is now much rarer in many urban and agricultural locations. This might suggest that moths dependent on resting on this and other green-grey lichens are losing available resting places?

The situation will not be clear cut, as some nitrophilous lichens are green-grey, but the general loss of background seems likely.

A quick look at the mapped distribution of the Merveille du Jour on the awful new version of the NBN suggests it is recorded over much of the area where Xanthoria has spread, suggesting it might be a suitable species to study for any distributional change.

Or has all this been done?

Posting in ignorance and now creeping out again,

Alan S.

Reply

Comments

Joe Botting's picture

Intriguing

I'm afraid I can't answer this one, Alan, but it is a very interesting idea - rather analogous to the famous peppered moth evolution.

There are probably a lot of moth trappers on here with records going back many years... so has anyone noted a decline in the Merveille du Jour, and if so, has Xanthoria been colonising locally at the same time, at the expense of Parmelia..?

nightfly's picture

Hi Alan,Further to the

Hi Alan,

Further to the possible relationship between the colouration of the moth and the lichen, I posted a Merveille du Jour not too long ago and had a 'lichened form' Scalloped Hazel moth larva in the shot also- the terminology would lead you to believe the SH larva has either nourished itself on lichen or is just camouflaged to blend into it. Possibly both.

http://www.ispotnature.org/node/371503

http://www.ispotnature.org/node/371461

Just thought you might be interested in this. I didnt photo either against the type of lichen Jamie has- congrats to Jamie on top pics. My Scalloped Hazel larva was found on a low honeysuckle plant but there is lots of that lichen in the vicity on both trees and rocks.

Edit- one I did photo on a lichened covered rock but clearly a different type of lichen to Jamies, just similaly coloured.

Cathal.

Martin Harvey's picture

Change

I'm not aware of Merveille du Jour being highlighted as a declining species - it's not included in Butterfly Conservation's recent "State of Britain's Larger Moths" report as being one of the species in major decline.

I've trapped M du J in woods that don't seem to have a lot of the type of lichen that M du J is 'designed' to be camouflaged against, but trapping doesn't prove much about where the moths go during the day.

Several of the footman moths, which have larvae that feed on lichens, have been greatly increasing in recent years, which is being partly put down to an increase in lichens in areas where the lichens had formerly declined, as a result of improvements in air quality.

----
Entomologist and biological recorder