Insects/Spiders

Posted by John Blatchford

My three most recent articles (about Allis Shad, Salmon and Crayfish) continue my theme about the many and various ways in which human beings are affecting the natural world. My plea throughout is that we should step up research in ecology so that we have a chance of at least understanding the problems we are causing.

Understanding the Problems

Understanding a problem is always the first step in attempting to solve it. Where living organisms and systems are involved there are many levels of understanding to be considered. I think these can be summarised as: the nature of the problem; the ecology of the organism(s) involved; and the role these organisms play in their habitat.

The Nature of the Problem

Often observation of the natural world reveals that something is changing. Very often (probably ‘usually’) this is first ‘picked up’ by amateur naturalists. For example bird-watchers might find a particular species becoming rarer. Specialist research is then required to discover if the observation is accurate and widespread.

Ecology of Organisms

If there is a real problem then the organism needs to be studied in detail. Ecological studies begin with two basic questions; what is the full life-history of an individual like?, and how do populations of the organism interact with one-another?. The full study of the ecology of all living things on earth is an enormous task, and one that is still in its infancy.

Habitats

Once the individual organisms themselves have been studied there still remains the incredibly complex question of – how do these organisms interact with one-another and the rest of their habitat? Only once all these three aspects of the problem are understood can we begin to think sensibly about possible solutions.

Inappropriate Solutions

Sometimes the urgency of problems in the biological world leads to an urge to attempt a solution before the exact nature of the problem, and the likely consequences of the proposed solution, are fully understood. Inappropriate solutions do more harm than good, they sometimes bring temporary relief but lead to unexpected consequences (see my article about the Cane Beetle and Cane Toad in Australia).

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Posted by John Blatchford

(This blog relates to three of my articles, 'Insect Traps' ,'The Lanternfly' and ''Fly Exhibition in Paris'. These refer to two major exhibitions, one in Edinburgh and the other in Paris.)

Scientific interest in natural history began with the building of collections. Specimens were killed and preserved but, since the colours often faded rapidly in dead specimens there needed to be a record of the appearance of the living creature (or plant). Before photography the only way to capture an image was to paint it, so it is not surprising that many of the early naturalists were also accomplished painters.

The interesting thing for me is that the paintings of collected specimens often go way beyond what is needed to simply record the information. The primary concern was to capture all the details accurately, but usually there was also an attempt to build a set of these ‘snapshots’ into an aesthetically pleasing whole. The artwork displayed in both exhibitions shows this concern.

Most of the early collectors started out simply recording details and then moved towards pleasing designs, but Eugene Seguy is somewhat of a special case. He was originally a designer, and later he became an entomologist. His early work with flowers is pure design, the work on Butterflies is a mixture, and the later paintings of flies (see below) has moved away to focus entirely on the detail.

(I realise that Seguy's fly paintings are not easy to find on the exhibition website, so here are the instructions: go to the exhibition website then click on ‘Decouvrez l’exposition’. This leads you to a graphic, and you want to be in room 6 (Decouvrez le people mouche). When you get there you will be able to click on the link to ‘Les debuts’ (top left). Here you will finally see a photo of Eugene Seguy and two of his ‘fly’ plates.)

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Posted by John Blatchford

Deepest France!

I am still waiting (after more than a month) for ‘France Telecom’ to repair my line. Until it is fixed I am working around the problem of an internet connection. This is why I have been ‘absent’ – when so much is going on. All my local friends here are ‘peasant farmers’, and they are very concerned about the bee crisis. I have been doing my 'blogging' in the village!

People here are very suspicious about any food that comes from an unknown source – the local ‘supermarket’ displays ‘origin’ for every product and if it is not ‘Lot et Garonne’ people avoid it!. ‘En plus’ there is a very local barter system in operation – most of what people eat comes from within the village ((I’ll give you some eggs for your honey). Everyone is worried about the current Bee Crisis. They are ‘peasants’ but all except me have ‘ADSL' and read widely.

What can we do? Here people are very careful about which ‘produits’ they use. I have been told (NO – I have been ‘instructed’ – ) to put nettle leaves under my tomatoes, or at least to drive a copper wire into the stems before I resort to ‘sulphating’. Any food that does not come from within the village might have been 'treated' and it is viewed with suspicion! (Personally I think this ‘the right way to go’!).

I brought a load of crayfish back home after a weekend in the next ‘Departement’ with friends. Nobody here was interested, although locally caught crayfish are a delicacy. That’s how deep it goes. And it is GOOD – at every meal (each of which last several hours!) you are given the detailed history of every part of the menu. It would be unforgivable in this part of France to use Spanish strawberries when local ones were available. If it is not the season for melons – then don’t eat melons! Simple really.

Back to my Bees. There is a lot of knowledge here – not ‘book-stuff’, but ‘life-stuff’. My friends here are very aware of the problems with Bees in America, and even more aware of the potential consequences than most. They do not use pesticides, and everything they grow is ‘organic’ – by default. They know where every morsel of their food comes from. Our bees are safe here, for the moment!

My friends here are wise in ways that we have forgotten – we would do well to listen to them!

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Posted by John Blatchford

Personally I don’t think this is more worrying than any of the other species of invertebrate that are reaching ‘endangered’ status. But the whole phenomenon is very serious indeed!

Most people are unaware of the extent of this impending disaster, and beekeepers might well become the saviours of the situation. Globally there must be millions of people who tend honeybees, and they have vast experience of what is ‘normal’ for a hive. I know that it is obvious when a hive ‘dies’, but it is the observation of what precedes this that might well turn out to be crucial. Beekeepers watch their bees (I did when I had a couple of hives) – and I have a feeling that these observations might lead to a better understanding of Colony Collapse Disorder.

I was talking to an old man yesterday (here in South-West France) who has kept bees for over sixty years. He gave up last year and destroyed his hives because ‘the bees have gone stupid and just wander about aimlessly’ – after several years of poor honey yield he had had enough. He blames the ‘produits’ used with the sunflowers. His theory is that the ‘low-grade’ toxicity of these chemicals affects the behaviour of bees. We do well to listen to the experience of ‘peasants’ in Europe – they have absorbed the lessons learnt by many previous generations!

So – what are we to do? I think the first thing is to gather as much information as we can from the people who keep bees. There are many – well qualified – entomologists who are actively researching the problem. But ? How many of them have actually kept bees? We need the anecdotes and observations of beekeepers to be added to this scientific investigation.

I have started a discussion on Suite101, not for my own aggradisement but so it can provide a forum. We certainly need to do something, and (although I am an ‘academic’ myself) I think we need to hear from the people who have worked with bees for years. Maybe someone ‘out there’ will pick this up and co-ordinate the information? (The article this blog refers to is called 'Colony Collapse Disorder').

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Posted by John Blatchford

‘The Harlequin’ explains how an intentionally introduced species of ladybird (both in the UK and the US) is damaging native species. Some help (through links to relevant sites) is given for anyone who wishes to contribute to the documentation of the spread of this species.

‘Bumblebees’ points out that many species of this important pollinator are now in crisis and links to sites that help readers get involved. The case of the ‘Great Yellow Bumblebee’ goes a little further and hints that this species might become a useful ‘project’ for anyone holidaying in the Hebridean Islands.

‘Asian Hornet in France describes the accidental introduction of a new species of hornet into South-West France. Here the identification is easy, and I give the email link to the professional entomologist who is actually working on the case. Because this development is so recent some of my links in this article have had to refer to French websites, but anyone holidaying in South-West France can confidently email Jean Haxaire because he understands English very well. (I have been in contact with him myself and he welcomes any help from the public).

‘Freshwater Pollution’ describes the different ways in which members of the general public can ‘keep an eye on’ the water quality of streams. Fishermen in particular might like to do a little sampling of the invertebrates lurking in the waters they fish regularly? This would allow them to alert the professionals to cases of pollution.

I hope these articles encourage a few people to become involved in this sort of work for two reasons. First because the professionals really do need help, and second (and equally important in my view) because the more the general public becomes aware of ecological problems the more chance there is of public pressure being put on policymakers.

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Posted by John Blatchford

The classic story of the rise of the melanic form of Biston betularia in response to industrial pollution is the example given to thousands of students to illustrate how Darwin’s theory of evolution by natural selection works. The story is a good one, and it illustrates the point very clearly. Unfortunately it might well be wrong!

I am not suggesting that anyone has set out to mislead – but some of the original research done into the camouflage of the moth is suspect. Moths were released or placed by hand on the trunks of trees in the daylight, but in normal conditions they hide under branches as dawn approaches. The visibility of the moths was considered from a human perspective, ignoring the fact that birds can see UV (what looked like good camouflage to humans turns out to be less good for birds!).

It was also assumed that records made in the Manchester region (UK) were typical of population changes worldwide. This turns out to be untrue. In some places the relative numbers of dark and light forms of the moth are the ‘wrong’ way round!

If the dark form was selected for by the destruction of lichens due to industrial pollution in the first place, then a return to the light form ought to follow the return of lichens to trees when air quality improved. Unfortunately (for the story) studies in Liverpool (UK) have shown that the numbers of light moths increased before the lichens were able to return to the trees.

Something that worries me (personally) is that there seems to be no reference that I can find to the caterpillars of the light and dark forms of the moth. Surely this is crucial if we are dealing with camouflage and predation by birds?

With all these criticisms of this classic story (and more that I have not mentioned) I think it is time to remove the Peppered Moth from Biology Textbooks. It should be replaced with a more ‘robust’ example of species change over time and its causes, maybe Flores Man?

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Posted by John Blatchford

When we talk about animal adaptations we are often guilty of anthropomorphism. What I mean by that is that we easily slip into describing things as humans would experience them. We talk of woodlice ‘liking’ damp places, or Kissing Bugs ‘preferring’ human blood, but a moment’s reflection tells us that this is not what we really mean – it is simply a well-understood ‘shorthand’. What we really mean is that woodlice have behavioural responses which lead them to damp places, or that the kissing bugs have evolved mechanisms which increase the chances of them feeding on human beings. There is little harm in this, as long as the ‘shorthand’ is understood for what it is.

Things become more complicated when we talk about adaptations like the eyespots often found on the wings of insects. Do they really ‘scare’ predators? Or do they ‘evoke responses’? If you try the following link (Don’t try this link if you have a heart problem!) – you might well have a reaction that you could describe as ‘scared’, but do you really think there is anything inside your computer that could harm you? I would suggest that our reactions to images are in some ways (initially at least) similar to the reactions of other creatures. Evolution equips animals with ‘hard-wired’ responses that aid survival.

Predators respond immediately to eyespots because they are ‘wired’ to behave in that way. They do not ‘see eyes’ and ‘think’ they might be another animal any more than Tinbergen’s famous stickleback ‘thought’ red post-office vans were other male sticklebacks! (Tinbergen described how his male stickleback would respond with aggressive behaviour when the – red – post-office van drew up outside his house. Normally sticklebacks reserve this behaviour for other male sticklebacks, who have red breasts.)

This leads me on to the interesting case of the Lanternfly. In addition to the prominent pair of eyespots on the hind wings this insect has a large protuberance on the head that looks rather like a caiman or crocodile. If you suggest that this might cause a ‘startle reaction’ in predators you might well be met with a response like: ‘surely that wouldn’t fool a bird’ – or – ‘it’s far too small to be scary’. My point here is that it is just possible that predators in the same habitat as the Lanternfly might well have evolved responses to ‘caiman-like’ things. Any image fitting the ‘pattern-recognition’ template in the brain would evoke the adaptive response! (Tinbergen would call this an ‘Innate releasing mechanism’)

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Posted by John Blatchford

Edinburgh this year (between 2 March 2007 and 16 September 2007), and London next year at Buckingham Palace, gives the general public an opportunity to see paintings and sketches by Leonardo da Vinci, Mark Catesby, Alexander Marshal and Maria Sibylla Merian. “There is a common denominator that links all these artists. It is the profound joy that all feel who observe the natural world with a sustained and devoted intensity.” (Sir David Attenborough).

Anyone who is interested in natural history should make the effort to get to one of these venues, or both (as I intend). Edinburgh is a beautiful city, and London has its attractions! The exhibition itself (Amazing Rare Things) will take up half a day if you read all the explanations, listen to the audio commentary and take a little time to reflect. I’m sure you will be able to find things to do for the rest of the trip – maybe including the Zoo and the Royal Botanic Garden in Edinburgh, or the Regents Park Zoo and Kew Gardens in London.

After absorbing the sheer beauty of the works exhibited I began to think about the ‘mind-set’ back then. A whole new world was beginning to open up for European Naturalists, and they attempted to classify everything they saw. The obsession with describing (and painting) every last detail has continued, and many who are interested in the natural world are still more concerned with the name of a creature than what it does. This is very unfortunate. At a time when the planet is undergoing major changes it is crucial that we begin to understand how biological systems actually work.

If taxonomy was the ‘watchword’ of the past, then ecology should be the one for the future.

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Posted by John Blatchford

Many of the environmental problems that currently worry biologists do not have quick or easy fixes. Usually there are many different species involved, and the relationships between them can be very complicated and far from obvious. There is a lot of information available in the specialist literature, but distillation of this for public consumption often oversimplifies the issues. This is very unfortunate because effective intervention will often need action at governmental level, and pressure from a well-informed general public is essential.

Some of my articles attempt to tackle important issues in small chunks. For example the problems facing Coral Reefs are developed in several other articles. The relationship between shell-collecting and the Crown-of-thorns Starfish is touched on in the article about the Giant Triton, but I also try to explain how the starfish is an important member of the reef community.

The same article about the Giant Triton goes on to look at the relationship between agricultural run-off and Coral Reefs. This effect is not at all obvious. Increasing the amount of nutrients available to the coral animals causes them to eat less of the eggs and larvae of a starfish that will eat them when they grow up!

By concentrating on one or two species at a time, or going into details of one or two relationships, I am able to keep the science accurate. Attempting to cover many aspects and inter-relationships in one short article would require too much simplification and obscure the complexity.

I think it is important to present scientifically accurate biological information in a way that can be understood by non-scientists. Over-simplifying issues simply insults the reader’s intelligence.

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Posted by John Blatchford

Fairyflies can be extremely tiny (see my article on Greenhouse Thrips), and their world must be very different from the one we know. Some species are smaller than a few of the single-celled organisms that exist today, and the mystery for me is how they manage to have such minute structures. Fairyflies have all the usual insect parts (digestive system, muscles etc.) and these are all composed of many cells – how they manage to have functional cells of this size?

When it comes to their physical environment things become weird. For such small creatures the differences between the viscosities of air and water are small. For them the air must feel like a thick soup! – with water just a little bit thicker. It is true that they have wings, but these are used much more to ‘catch’ the air than to actually fly through it. They drift on air currents much like baby spiders who use a silk thread to help ‘catch’ the wind.

Flying through water might even be easier. Water (in an aquarium or pond for example) can often be remarkably still. Under these conditions Fairyflies that parasitise water creatures can flap their wings and fly quite effectively. What I do not understand is how they manage to move from air to water. The surface tension at the water/air interface must be enormous for them. Perhaps they cannot cross this barrier ‘on their own’? Maybe they can only move from air to water when they are inside their (much larger) hosts?

These are just a few of the things that I cannot understand about very small creatures. If any reader knows some of the answers I would be very grateful! (Enter the discussion)