Whether or Wither the Weather; Coiling, Uncoiling, Sucking and Leverage.

July and August 2015 will be remembered as very poor summer months in this part of the world, with some rain on the majority of days, generally low light levels, cool temperatures and very few, still days. But we had been warned.SDIM4312 (2)

As Dame Julia Sligo, MBE, FRS, the current head of the UK’s prestigious Met Office points out in a recent blog which you can read by clicking here, there are many possible reasons for this – principally a pronounced El Nino event off South America, a disturbed Jet stream, the Spanish plume and North Atlantic water temperatures 2 degrees C colder than usual. I do suggest you read this piece since you’ll see just how accurate the Met Office forecasts now are, and this is before the switching on of a new supercomputer.SDIM4016 (2)

Our 5-day forecast is now as accurate as our 1-day forecast was when I started my career. This enables us to make so many decisions that keep us safe, protect our property, keep our infrastructure running and even when to go out and enjoy the sunshine!”SDIM4328 (2)

The problem is that up here, the BBC rolling 4 hour forecasts have proved seriously inaccurate this year when it comes to predicting rainfall events, though interestingly XCWeather, which we also scrutinise, has predicted rainfall with much greater accuracy. I wonder whether someone else has noticed that the Met Office results don’t always match the performance extolled above, since this month we heard that the BBC has terminated its very longstanding contract with the Met Office, and will seek a new provider of forecasts in future. Nothing like a bit of healthy competition I say, but I think for now we’ll continue to consult multiple sources through the weather critical period when we have to get hay off our fields.SDIM4314 (2)

I’m a naturally cautious fellow, and am concerned that previous strong El Nino’s have been followed by severe winters, and indeed we’ve experienced a few recently, particularly in 2010 when we had the coldest December since records began. But back then we had no livestock to be worried about. Now, one has to contemplate how one would feed them if, say, we had snow on the ground for 3 months, rather than weeks, and plan accordingly.SDIM4248 (2)

So we were delighted to be able to salvage nearly 50 bales of half decent hay in the only 3 day rain free period we’ve had in the last 2 months by cutting some of our wet valley bottom meadow – which just 2 years ago was shoulder high mono culture soft rush, Juncus effusus. Even if it is predominantly Velvet bent, Agrostis canina, and Tufted hair-grass, Deschampsia cespitosa, it’ll provide a useful back up, should the worst materialise.SDIM4319 (2)

The weaned male lambs have left us, to be fattened on elsewhere, so the land is much quieter now, though Carwyn who took them to the slopes of the Black Mountain (in the far central distance below) told us whilst here, that in his parish there are about 90 small family farms, which all have owners around 65 or older. Only 6 have sons who are going to carry on in farming. In 15 or 20 years, who will manage these challenging uplands? How will the landscape change? Is there perhaps a role here for new migrants, prepared to roll up their sleeves and do the hard grind that is the lot of the local land stewards? Or will the land be left to scrub and forestry?SDIM4033 (2)

Perhaps not surprisingly with such a poor summer, the eagerly anticipated annual Welsh fifteen butterfly moment, when I can count over 15 butterflies on our many Buddleia bushes at the same time, has not yet arrived – and I’m beginning to think that it might not this year. Even the ‘common’ Small and Large Whites, Pieris rapae and P. brassicae, have only been seen as singles. But it was a real thrill to see a Hummingbird hawk-moth, Macroglossum stellatarum on 3 occasions when the sun shone.SDIM4237 (2)

Watching these amazing insects flit speedily, from flower to flower of the Buddleia got me wondering how butterflies and moths locate the nectar source that they’re after, so efficiently. Do they use sight, or smell or touch?

It seems it’s a combination of all 3 senses. I first read a paper specifically on Hummingbird hawk-moths, click here, which explains that a mixture of colour, patterns and luminance or brightness of patterns, are all influential in determining how one of these moths locates a flower.SDIM4238 (2)

Once the proboscis is actually inserted into the flower, the many sensitive hairs or sensillae on the outer surface of the proboscis will pick up information about where the nectar is actually located within the flower, and once learned for a particular flower type, enable the moth to whirr from flower to flower at great speed and with a high feeding efficiency. It also seems that whilst many insects perceive colours in the blue spectrum better, in experimental trials, these moths preferred to hone in on model flowers with small yellow centres – in fact just like the Buddleia flowers shown.SDIM4243 (2)

But I then began to wonder how the butterfly, or indeed moth, actually controls the proboscis. From fossil and taxonomic studies, it seems that Lepidoptera evolved their own unique form of proboscis in a single, diversionary evolutionary event, from the more typical insect feeding apparatus, (though subsequently refined and tweaked in different species) rather than in multiple different, evolutionary pathways. It developed from the galea of the chewing mouth parts which most other insects possess, and over time the other maxillary structures have reduced in significance. (Stylised cockroach galea first, then butterfly, below).cockroach_maxillamouth_butterfly.agifHowever, not all adult moths and butterflies actually feed through it – in some it’s vestigial, if the adult stage only survives for a very short time. But essentially, in many species, it’s a very sophisticated organ for sucking up liquids – principally energy for flying fuel – as nectar, or water.SDIM4210 (2)

In its resting condition it is kept coiled beneath the head, and sometimes invisible as in the Common blue butterfly, Polyommatus icarus, above, but can be rapidly deployed for foraging by a combination of internal muscles and a hydraulic system involving the insect body’s haemolymph (a combined blood/lymph circulatory fluid), and valve systems. Opening valves and releasing the fluid, inflates the coiled proboscis a bit like blowing on a coiled-up party whistle. Except that the proboscis has an in-built elasticity which causes it to rest in a partially uncoiled state as in the Gatekeeper butterfly, Pyronia tithonus, below on Sneezewort, Achillea ptarmica. SDIM4181 (2) In many butterflies it can be nearly straightened.SDIM4284 (2)But is often seen when feeding, with a knee bend, about a third of the way along its length.SDIM4244 (2)

The micro-anatomy of the proboscis is also fascinating, consisting of two halves or galea, which are roughly semicircular in cross section but join to create the hollow central feeding tube, up which liquids pass. Click here for some great electron micrographs showing the detailed cross section of the proboscis and its central channel feeding tube. Inside the head, an efficient sucking pump, with valves connected to the butterfly’s intestine, activates the sucking process once nectar is located at the tip of the proboscis. Boluses of fluid are drawn into the chamber of the pump from the proboscis, and then moved on into the oesophagus.

But how successful is this?SDIM4283 (2)

It turns out to be influenced by the concentration of sugars in the nectar and hence how viscous it is, and there are some examples from an excellent review article by the same Harald Krenn on Lepidopteran feeding mechanisms, which you can read by clicking here. You’ll discover, for example, that in the Painted Lady butterfly, Vanessa cardui, it’s been measured that an average meal size is about 28 microlitres of nectar, which it can obtain from about 150 flowers probed in about 50 minutes. Using artificial flowers, this can equate to about 15% of its bodyweight ingested in just 2 minutes, and up to 40% of bodyweight in a feeding session, before it’s full. SDIM4297 (2)

So, a pretty successful mechanism for harvesting high energy food in a limited period of time – just as well in a summer like this when sunny intervals, and so feeding opportunities, have been mainly fleeting. My final interesting information on this wonderful feeding apparatus is that when the adult butterfly is within the pupa, the proboscis develops in its two separate halves or galea. (Small Copper butterfly, Lycaena phlaeas, below).SDIM4157 (2)

We all know that butterflies have to ‘inflate’ their wings after emergence, by pumping fluid into the collapsed veins. At the same time as this is occurring, it’s getting to work on joining the two galea together to form a functioning, sealed and single proboscis. SDIM4205 (2)Starting at the head end, and with the aid of a drop of fluid from its mouth as a temporary bonding or lubricating agent, it sequentially pumps fluid into the inner core of the two galea and then moves them in an anti-parallel manner, side by side, sequentially coiling and then uncoiling. This causes a line of hooks or spines on the edges of the galea to engage with each other and lock the two halves together – a little like a zip fastener. Under the control of hormones produced by the insect around the time of emergence from the pupa, which softens its hard exoskeleton material for just a few hours, this link up is able to take place. The tissues then harden quite quickly and thus the joined proboscis attains its permanent durable sealed feeding tube structure, and cannot split back into its separate halves.SDIM4301 (2) It’s still not clear just how, in butterflies which have to emerge from underground pupae, pushing up through the soil first, the galea are able to delay this engagement process until the butterfly is safely above ground.

So next time you watch a moth or butterfly beginning to feed from a flower, maybe marvel a little more about what enables it to do this!SDIM4241 (2)

Regular readers will have heard about our previous efforts to correct the direction of our ram’s horn’s deviant curve, to divert it from his face. In the end we clearly hadn’t done sufficient, so another session with the heat gun was required. Fortunately, this time, with the benefit of more horn to pull on, I felt that I’ve achieved a better result, though whether it’s a final solution remains to be seen. Let’s just say that considerable leverage was required, but that Doublet apparently bears us no ill feelings, and is still extremely biddable.SDIM4132 (2)

The days now have a definite autumn feel, and work has been concentrated more recently on those areas where maintenance is needed to avoid an exponential increase in the size of the task – no more so than our shared access track, where vegetation growth around our central drainage channel can soon impede run off.SDIM4309 (2)And where any temporary blockages soon cause overflow and consequent erosion.SDIM4311 (2) The garden takes back seat at time like this, waiting for the bulb order to arrive.SDIM4041 (2)SDIM4094 (2)SDIM4113 (2)SDIM4102 (2)SDIM4050 (2)SDIM4043 (2)SDIM4023 (2)SDIM4114 (2)SDIM4055 (2)And even the Drinkers, (moths), Euthrix potatoria, think it’s better to snooze.SDIM4065 (2)SDIM4069 (2)

10 thoughts on “Whether or Wither the Weather; Coiling, Uncoiling, Sucking and Leverage.

  1. Isn’t nature rather marvellous. I enjoyed your detailed explanations on Butterflies, although I did not really understand the diagrams, their anatomy is so unfamiliar. Maybe its my memory but can’t recall you speaking about heat guns and Doubtlets horn, my imagination can’t quite imagine how you used a heat gun to sort that either but he does still look jolly. We have the same as you this weekend, lots of rain and murky weather. What is the last photo of?

    • Hello Julie,
      For the background to horn bending see my post of 26/04/2015 – Luminosity and Boiling Horn.I was equally dubious when I was first told this is what we had to do with his deviant horn.. As for the last photo, which clearly needed better labelling, its the head on view of the male Drinker Moth which is photographed above – which I found in our wet meadow this month. They have amazing banded antennae, shaped like snow shoes, and if aroused look even more spectacular – have a look in my moth diaries for an image of this. I tried to get a response from this one by tweaking the stem but it refused to co operate, and just clung to its stem. If you ever see one flying around at night, it may well explain how it came to get its name – its a big hairy moth and seems to fly/crash around in a very random fashion as though its been on the bottle,
      Best wishes

      • You just made me laugh out loud! I shall keep on eye out for one. 🙂 Followed your link too yesterday to the Met Office blog, I was interested to read your comments on the alternative weather forecaster, one I was not aware of but will look out for.

  2. Such beautiful photographs. I will be thinking of their proboscis more when I watch the butterflies drinking. We have a lot of Hummingbird Hawk Moths this year. They are big beasts compared to most of the delicate butterflies and I was wondering if they took a lot of nectar to fuel such active flight and the large body. I had a feeling they could really suck the flowers dry. I must be good to have your hay in, especially after such a rainy time in the U.K. Amelia

    • Thanks Amelia – I can imagine HHM’s will love your warmer climate, and will indeed consume big amounts of nectar, since as you say, body weight in the larger moths is dramatically greater than butterflies – and indeed is why most larger night fliers can’t easily just fly off if disturbed during the day, needing to ‘shiver’ first to get flight muscles up to a working temperature,
      Best wishes

  3. Lovely autumny photos as usual but I would like to know too what is the last photo ?
    Next time I see a butterfly..(.where are they all?).. I’ll really look to see how it is feeding. Thanks again for such an interesting blog – I learn something everytime!

    • Thanks Marianne, The last photo was a Drinker moth head on – see a bit more in my reply to Julia above. Our meadow butterflies, which flew mainly late June/early July were fine, but the late season garden ones seem to have been hammered this year – just not enough opportunities for them to fly. I keep scanning 10 days ahead to see if there’s any hint of an Indian summer, but although its now looking a little drier, there’s no sign of any sun or warmth…
      Best wishes

    • Thanks Inese, I always love this time of the year for the cobwebs … they never seem to be quite the same, or in quite the same places…so I’m always drawn to photograph them. Of course they’re there for much of the year, its just climatic conditions which make them more obvious – a peep into the daily life and death battles between insects and arachnids!
      best wishes

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