Blighty-Bugs

A butterfly house is a curious series of rooms –
A bit like a tropical farm,
Where exotic moths can dine on exotic blooms,
With wingspans as wide as my palm.
Or so I had hoped – but this was no Forest of Arden –
Or jungle of scent-heavy petals –
But flitting about were familiar sights from the garden,
And all that was growing were nettles.
It turned out they mastered in only British varieties,
Tortoiseshells, coppers, and whites.
Pretty, but small – the kind that give gard’ners anxieties,
Or taken-for-granted delights.
Oh sure, the elephant-hawks are impressive as caterpills,
Stripping the fuchsia to shreds,
But overall, any good hedgerow holds similar thrills,
Without the need of these sheds.
Although, as a lifelong dweller of chalky downs,
And the home-strip lads that brings.
It was good to see some strangers from limestone towns
With a Northern brogue to their wings.
So yeah, I guess I enjoyed them in concentration,
A blaze about the flowers –
And proof that beauty can still exist in our nation –
Because all of these ones are ours !

Of course, I have mused on butterflies numerous times before, but after writing this I decided to put my prose where my poetry was:

I asked a few AIs for a plan to build such a self-sustaining glasshouse, with a list of the fewest number of native plants.  Here is the consensus:

Firstly, a fair spread of readily-available lepids:

The months listed above are for typical outdoor activity, so may be extended indoors with earlier Springtime starts and possibly a second or third brood.  If the glasshouse is insulated but not heated (except to keep it above 5°C through the Winter), this will mean that not all of these species can be self-sustaining, as some of them migrate (Clouded Yellow, Hummingbird Hawk-Moth), and fresh stocks will need to be brought in each Spring (this is something all butterfly houses need to do).  I can see making use of an ornate pupilarium with windows to watch them ‘hatch’.  We will also have some structural little brick towers around to provide dry pupation sites (and resting spots for the Walls).

I’ve included the Brimstone, as it’s the classic bright-yellow species that possibly gave all lepid’s the name of ‘butter-fly’, but it should be noted that their numbers aren’t doing great at present, which could certainly cause problems.  Their caterpillars only eat buckthorns, which aren’t exactly the smallest shrubs, but perhaps we could have a few in the centre of the glasshouse and make a feature of them ?  (By the way, I call it a glasshouse instead of a greenhouse to emphasise that it will be considerably larger than the things found at the bottom of the garden for growing tomatoes in.)  I’ve also listed the Marsh Fritillary, which faces similar worries, but otherwise fit in nicely !

I’d also like to introduce Rose Chafer beetles (Cetonia aurata) for a bit of metallic variety.  Their grubs live on rotting wood, so we’ll need a decomposing stump in a corner (maybe from when we prune the alder buckthorn ?), but if it also supports fungus and woodlice, it could be quite a feature.  Their adults eat nectar, just like the butterflies, and are on the wing May-Oct.

And, since aphids and mildew are inevitable, I decided to also include the following ladybirds:

7-Spot  (Coccinella septempunctata)  –  Mar-Oct  –  the familiar red-with-black spots  –  both grubs and adults eat aphids
Kidney-Spot  (Chilocorus renipustulatus)  –  Apr-Oct  –  black with two red spots  –  both grubs and adults eat scale insects likely found on the woody plants (alder buckthorn, honeysuckle, ivy)
22-Spot  (Psyllobora vigintiduopunctata)  –  Apr-Aug  –  yellow with black spots  –  should make for a good mildew-munching colony in the honeysuckle and the rotting logpile

It will be interesting to see if there are sufficient levels of aphids, scale, and mildew to sustain populations.  Perhaps not initially, but over time I’m sure there will be a veritable banquet !  A harder problem will be keeping out the harlequin ladybirds from crashing the party…

If we were really smart, we could include a free app that will identify each of the above species (adults and caterpillars) so that visitors can point their phones at one and get its name and details.  This data can also be used to record when the adults first and final flying days are each year.  But I don’t think it can help with keeping a census unless it could also identify individuals so as to not count them each multiple times.

But anyway  –  the plants need to be natives, and robust, and able to regrow quickly after heavy defoliation by caterpillars, while also provide nectar for the butterflies/moths for the entire time they are flying.  Indeed, I wanted to make sure that there were two different nectar sources incase of any issues, though I held off doing the same for feed plants, as a lack of food will be an important population control (though many species do have multiple food options, but this was not deliberate).  Here’s the answer I got:

Of course, the lepids will have no birds or bats preying on them, so careful management is needed to preventing boom-and-bust cycles.  To some extent, there will be some predation from the ladybirds, who will happily eat butterfly eggs if aphid numbers are low, and parasitic wasps have a knack for getting into everywhere, from our glasshouse to the bodies of caterpillars.  I suppose we cold also net the surplus butterflies and release them outside of the glasshouse, but this would only work legally for species that aren’t endangered, aren’t migratory, and occur naturally in the local environment.  We could even make a bit of an event of the release, could be good for PR – though probably best not to include cabbage whites…

But thinking about it, a few plants above are described as being in pots, but probably this should apply to most of them (except for the alder buckthorn, the ivy, and the honeysuckle, which will each be istraight into soil a metre deep) – not only will it allow for different soil-types, but if any particular plant is over-grazed, it can be whisked away and put into quarantine, to prevent a population boom.  Replacement pots would be grown ‘backstage’, ready to understudy and provide fresh foliage.  Obviously, these are likely to be larger than the average garden terracotta, and contain more than one nettle or tussock of grass, but still modular enough to allow for easy relocation.  his also allows for the containers to be raised up closer to eye-level – handy for low-growers like forget-me-nots !

Hopefully, these plants will be self-sustaining (or at least self-seeding), though they don’t all love full Sun, and some like the primroses and violets will be best kept under the alder buckthorn for shade.  We can also use an evaporative cooling system for those plants that favour wetter conditions (bugle, violet, devil-s bit scabious).  Actually, the walls don’t need to be nothing-but-windows, but can include structural brickwork too, more like an orangery perhaps…  Also, where possible the air circulation will be internal, rather than having too many vents, so as to prevent too many unwanted visitors (even with a fine mesh over them).  As for the public, they will enter through an ‘airlock’ of sequential strips of hanging, overlapping, heavy plastic as is common in butterfly houses.  They’re also good for building anticipation…

To be honest, this thought-experiment started with just a dozen species and a handful of plants, but I kept finding that I could utilise the existing flora to add more butterflies, except…well, another source of nectar wouldn’t harm, and this also allows for another species as a side benefit, except this one hangs around for longer so needs another Autumn bloom,…and you can see how things started getting a bit out-of-hand.  But I think this is now a good balance of providing a decent selection of flyers in any given month.