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Dennis Dell sent me the following message and felt that UK Butterfly visitors might have an opinion So - what do you all think?

During a meeting on Saturday of the Upper Thames Branch of Butterfly Conservation, an interesting discussion was started, but not pursued, about what constitutes a 'woodland butterfly'. Some members argued that there was no such thing, in the sense that no butterfly is found exlusively in dense parts of woods, but they are associated with the edges of woods, sunny rides, or glades.

It got more complicated, because members then asked how do we define 'a wood' anyway?

We can certainly talk about just a few species which have a dependance/strong association with trees in woods [either as larval food source or assembly point] .

• White Admiral [assembly, parading]
  Purple Hairstreak [larval food source, assembly, parading]
  Purple Emperor [larval food source, assembly, parading]

however, there are species which may be found in or near woods, but which are also found along lanes/hedgerows which harbour their larval food source and/or parading/assembly trees:

• Brown hairstreak
  White-letter hairstreak
  Black hairstreak

Certain fritillaries are also associated with woods, but have no particular predeliction towards trees, and fly quite low; particular the two pearl bordered and high brown frits. What about the Silver-Washed ? Is it not seen in the west country outside woods?

In addition, the Wood White is not exclusively a woodland species either; we find it on railway bankings in North Bucks, for example.

Thoughts/comments?

I suppose one interpretation of a "woodland butterfly" is that it is a species where one or more stages are dependent on the habitat that a woodland provides. This could be for purposes of courtship, larval foodplant, nectar sources, providing a cool environment in shade, etc.

But "what is a wood" is also a good question

I think the same discussion could be had for other characterisations such as "Chalk downland". Again, I'd say that it's not the chalk downland that is necessarily the requirement, but the habitat it provides. For example, the fact that Horseshoe Vetch is somewhat confined to chalk downland limits the distribution of Adonis Blue and Chalkhill Blue.

The more I think about it, the more I think that, perhaps, the characterisations (woodland, chalk downloand) aren't necessarily the best!

My 2p!

Cheers,

- Pete

Certain fritillaries are also associated with woods, but have no particular predeliction towards trees, and fly quite low; particular the two pearl bordered and high brown frits. What about the Silver-Washed ? Is it not seen in the west country outside woods?

The fritillaries are/were associated with woodland glades, as the glades provided a warm micro-climate and source of food plants. I understand they always occurred elsewhere, in places that were also warm and sheltered. My local colony of Small Pearl-bordered Fritillary (Priddy Mineries) is on acid heath, with very few trees to be seen. This also supports other former glade-dwellers, such as Dingy Skipper and Green Hairstreak.

However, I've never seen a Silver-washed Fritillary far from trees, and there were plenty to be seen this summer. Usually they are in woodland rides or nectaring/patrolling on the edge of woods, but at the end of their flight period they dispersed a bit more, nectaring on brambles and the like, but still always near to clumps of trees at the very least.

In the case of Silver-washed Fritillary, the eggs are laid on tree bark - so I guess the combination of trees and violets would lead you to woodland!

Cheers,

- Pete

Pete Eeles wrote:I suppose one interpretation of a "woodland butterfly" is that it is a species where one or more stages are dependent on the habitat that a woodland provides. This could be for purposes of courtship, larval foodplant, nectar sources, providing a cool environment in shade, etc.

But "what is a wood" is also a good question

I think the same discussion could be had for other characterisations such as "Chalk downland". Again, I'd say that it's not the chalk downland that is necessarily the requirement, but the habitat it provides. For example, the fact that Horseshoe Vetch is somewhat confined to chalk downland limits the distribution of Adonis Blue and Chalkhill Blue.

The more I think about it, the more I think that, perhaps, the characterisations (woodland, chalk downloand) aren't necessarily the best!

My 2p!

Cheers,

- Pete

Absolutely true Pete.
Its not so much about a woodland or downland. Its about how it is managed and the influence of other 'factors' or the environment e.g. the type of trees or plants growing, coppicing, grazing etc.

I agree entirely with what is being said here. However, for my extra 2p-worth, I would add that 'woodland butterfly' is not a formal, scientific term but more of an atmospheric tag that captures the imagination and encourages people to take an interest in their environment. In that looser sense, woodland butterflies very definitely exist. Admirals and emperors, speckled woods and purple hairstreaks, silver-washed fritillaries and brimstones, all these fly in my mental image of a British woodland. It is a romantic picture but also a real one. If more people shared it, perhaps more people would come to value woodland in itself and for itself. The same is true of the other categories of habitat - downland, wetland and so on.

Of course, scientific conservation work cannot be based on romance; but on the other hand, public good will and funding often do depend upon identifying attractive species or groups of species that will benefit from that work. 'Woodland butterflies at risk from motorway development' is a rather catchier headline than 'Motorway threatens certain unrelated butterflies, one or more of the life-cycle-stages of which are associated with trees'.

Just a thought.

Guy