An obvious answer to this question would be - caterpillars.  But when did butterflies first appear?  There are now some 160,000 species of moths and butterflies -worldwide.  Seemingly, they appeared some 100 million years ago  - in North America.  They evolved from nocturnal moths in the period when flowering plants were undergoing a major expansion (in the Cretaceous period).  Butterflies may have become diurnal to avoid predation by bats, or it may have been to take advantage of nectar production and availability [using the proboscis]. The butterflies and their caterpillars were able exploit the diverse range of food resources that these ‘new’ plants offered.  Butterflies moved out from North America to South America and then on to other parts of the world, though they probably did not arrive in Europe until some 17 million years ago. The evolutionary expansion of the butterflies has been investigated by researchers at the University of Florida; they analysed the genetic makeup of many species (from 90 countries).  They were able to build up a picture of the relationships between the various groups of butterflies and also determined their evolutionary point of origin.  They also catalogued the plants eaten by the caterpillars and it was found that some two thirds of butterfly caterpillars feed on plants from the legume family (the Fabaceae - peas and beans).  It is probable that the first butterfly caterpillars also fed on these plants. Research at the Georgetown University in Washington DC suggests that larger species of butterfly are ‘coping’ better with higher temperatures, associated with global warming.  Bigger wings seem to offer a greater range of movement and the opportunity to find new and suitable habitats.  Smaller butterflies are not faring so well.  The study involved an analysis of the range of some 90 North American species between 1970 and 2010, during which period the monthly minimum temperature increased by 1.5oF. Others have analysed the butterfly collections at the Natural History Museum, using digital technology.   The Natural History Museum’s British and Irish butterfly (and moth) collection is probably the oldest, largest, and most diverse of its kind in the world; some of the specimens date back over a hundred years The measurements of the various specimens were paired with the temperature that the species would have experienced in its caterpillar stage. It was found that for several species that the adult butterfly size increased as the temperature increased (during late larval stage). So, it may be that we will see a gradual increase in butterfly size as temperatures increase with global warming. Join the Big Butterfly Count ? Between Friday 14th July and Sunday 6th August , the big butterfly count will take place.   For full details visit : https://bigbutterflycount.butterfly-conservation.org/about Thanks to Angus for images.

Bumblebees (and bees) collect nectar and pollen.  Pollen is a vital food, used in the various stages of a bumblebee’s life. In Spring, newly emerged queens feed on pollen, then it is used to feed its their sister workers. The workers, in turn, take over the feeding of the colony (the larvae and future queens). If not enough pollen is collected, then the colony will not thrive, which can have significant long term effects.  Bumblebees are already facing many threats (from habitat fragmentation, agrochemicals and disease). The collection of pollen is a demanding process, and bumblebees will forage over a wide area.  They start their pollen collecting activities earlier than many insects as they can warm themselves up by ‘shivering’, that is, rapid muscle contractions which generate heat, warming the insects up ready for flight.  Bumblebees can fly in colder conditions and at higher elevations than many other insects. However, research at North Carolina State University has shown that the North American bumblebee (Bombus impatiens) can overheat when exposed to high temperatures (circa 42oC plus).  So,  if a bee is carrying a significant load of pollen and it is a hot day, its muscles have to work harder and the bee is at risk of overheating. A bumblebee loaded with pollen may be 2oC hotter than an unladen bee; it may be reaching its ‘thermal limit’ - a temperature at which its organs are damaged.  Climate change means that many parts of the world are now experiencing extreme weather events, when temperatures can reach into the forties. [caption id="attachment_39978" align="aligncenter" width="675"] Bumblee leaving foxglove[/caption] Increasing temperatures could affect the foraging activities of bumblebees in a significant way - affecting how much pollen is collected and how much pollination takes place.  If pollen collection is reduced then colony development is affected and so population numbers will be affected.  Bumblebees are key pollinators in natural and agricultural systems, and if their numbers decline there will be ecological and agricultural consequences.  

Scotland’s west coast has a number of temperate rain woodlands / forests. They are quite rare. The remnants of oak, birch, ash, native pine and hazel woodlands are small and isolated from each other. They are noteworthy for the diversity and richness of the bryophytes (mosses and liverworts) and lichens; found in abundance on the trees, rocks and on the ground.   Sadly, such woodlands have been in decline for some time. In the past, this woodland covered large areas of the west coast of Scotland, but much has been lost over the last two thousand years.  These woodlands / forests now cover a small area, just under 5% of the land. Factors that have contributed to the decline and loss of this woodland include:- mismanagement,  overgrazing by sheep and  invasion by non-native species [such as Rhododendron ponticum]. According to recent study by Scottish Environment LINK, deer now represent a considerable threat to the woodlands.  Whilst deer are part of woodland ecosystems, when their numbers increase beyond a certain point then they become a significant problem.  Deer numbers are now at historic highs in Scotland/  Money has been made available to manage surging deer populations, for example, through the provision of deer fencing.  However, the report considers that such fencing is “both expensive and often ultimately ineffective”.  More needs to be done if deer damage is to be reduced and allow regeneration of the woodlands. Developing a community approach to deer stalking and management will be important, combined with the use of technologies such as thermal and drone surveying. A greater focus on the management of roe and sika deer, combined with the removal of Rhododendron ponticum will be needed if the woodlands are to flourish and expand. see also : https://www.thescottishfarmer.co.uk/news/23637346.soaring-deer-numbers-see-new-powers-land-managers/   [caption id="attachment_39688" align="aligncenter" width="675"] Rhododendron ponticum, these plants were growing near the River Tay.[/caption] visit https://www.instagram.com/woodlands.co.uk/?hl=en  

Plants have existed for hundreds of millions of year - as algae, mosses, liverworts, ferns but flowering plants only appeared about 140 million years ago. The exact timing of their appearance is a matter of some debate (see article) They have been a massive evolutionary success, there are perhaps 300,000 to 400,000 species world wide.  They reproduce using pollen.  This is used to fertilise the ovules and produce viable seeds.  Most plants rely on insects to transfer this pollen to the ovules, indeed over 80% of flowering plants have relied on insects for this service.  To this end, flowering plants (Angiosperms) have evolved a number of inducements to attract insects : colour, scent and nectar. When we think of pollinators, we generally tend to think of bees, bumblebees, hover flies.  But when flowering plants first evolved, fossil evidence suggests that many of these flowers were quite small so it is probably that the first pollinators were also quite small, and hence able to access these small flowers.  The first pollinators were probably small flies, midges or beetles (more than 77,000 beetle species are estimated to visit flowers).  Quite when bees (and their pollen collecting activities) evolved is not known.   A recent analysis of the "family tree" of the families of flowering plants indicates when different plant families evolved and when various forms of pollination emerged.  Insect pollination is / was clearly the most common method of pollination,  and was probably the first means of pollination.  This analysis also indicated that other means of pollination (involving small mammals, birds, bats) have evolved several times, as has wind pollination.  Wind pollination seems to have evolved more often in open habitats and at higher altitudes , whereas animal pollination is associated with closed canopy tropical forests. The pollen of insect pollinated flowers is significantly different to that of wind pollinated species.  Flowers that are insect pollinated tend to produce pollen that is heavy, 'sticky' and protein-rich.   Pollen is an important constituent of the diet of many insects.  Wind pollinated species by contrast produce large quantities of pollen, the grains being light and small.

Lichens are plant-like organisms that are rather unusual in that they are an amalgam of two (or occasionally three) organisms : a fungus and algae (or cyanobacterium). They are symbiotic systems, where the partners of the association work together for mutual benefit.  The fungus makes up the bulk of the lichen's form (known as the thallus), it is a complex network of fungal hyphae that surround the algal cells.  The algae (green algae or cyanobacteria) are essential to the association as they can photosynthesise, fixing carbon dioxide and providing both partners with organic carbon compounds (often in the form of sugar alcohols). Some lichen species are brightly coloured. The colour may vary from a golden yellow to a deep red. The pigments responsible for these colours belong to the anthraquinones.  However, these insoluble, phenolic pigments can have toxic effects. To avoid harm by these pigments, the lichen exports* the pigment from the fungal component of the symbiosis. The pigment then accumulates / crystallises on the surface of the lichen. The layer of pigment crystals reflects harmful radiation (in the form of UV light) and also blue light, whilst still allowing enough light to pass through for photosynthesis by the algae / cyanobacteria. Exposure to UV light can damage DNA, inducing mutations.  The pigmentl layer is effectively a ‘sunscreen’ for the lichen. * Recent work at Imperial College and RBG, Kew has identified the genes responsible for pigment production, and the transport of the pigment out of the fungal tissue. In the past, certain lichen pigments were often used to dye clothing materials.    Parmelia saxatilis, also known as grey crottle, was used to dye wool for Harris Tweed.  This lichen is often found growing on tree trunks and gives a red / brown colour to the material. [caption id="attachment_39793" align="aligncenter" width="700"] Lichen and moss growing together  (thanks to Art for photos)[/caption] Woodlands TV has produced two short videos on the biology of lichens :- https://youtu.be/XQ_ZY57MY64     https://youtu.be/0djrOgKtGlk

I recently attended the National Allotment Society AGM, where the keynote speaker was Professor David Goulson.  His main academic studies focus on the threats to bees, bumblebees and other insects. He is based at Sussex University.  Back in 2006, he founded the Bumblebee Conservation Trust; a charity which has grown to some 12,000 members.  In his talk at the meeting, he made the following points : He loves allotments because they capture carbon and are rich in biodiversity.  They produce a lot of food.  Typically producing some 10 tonnes / hectare whereas farming productivity is about 3 tonnes per hectare.  The record on a 1m2 in an allotment is 10 kg, which is the equivalent of 100 tonnes / hectare.  Allotments not only produce good food for healthy eating, but people get good exercise through their gardening activities.  A study shows the ‘over-60s’ with allotments have longer life expectancies [controlling for other variables]. [caption id="attachment_40124" align="aligncenter" width="675"] A bee at risk of extinction.[/caption] There are over 300,000 allotment plots in the UK and some 90,000 people on waiting lists.  More allotments could help counter poor health and cut NHS costs. We should turn our cities, towns and villages into a network of nature reserves - essentially a form of urban rewilding. Gardens are a vital part of this, as there are some 400,000 hectares of them in Britain.   Prof Goulson is really keen on less mowing, more ponds and no pesticides. Interestingly, France banned pesticide use in public and urban areas, such as parks, back in 2014 - it is an example that we should follow. Even pet flea treatment is damaging to insect life.  The strength of the doses used means that the chemicals can pass into the environment - to grass, rivers, canals and pools.  Sadly, now 8% of gardens have some plastic lawns, and plastic hedges (and Wisteria !).  Plastic makes him despair.Plant diversity in pavements should be celebrated. Wild flowers / weeds are sources of pollen & nectar for pollinators.  Verges should be nature reserves.  A Scottish "On the Verge" group stopped councils mowing 8x a year and planted a seed mix to transform verges in their area.  Councils should mow less.  Some people may object, so people should strengthen their Council’s hands by writing to them and praising them for no-mow-May-type efforts.  The Buzz Club - has been set up, this is a citizen science project to see what works best for insects. There are lots of short films on his youtube channel . Bees and other pollinators need help.  He suggested lots of ways to help them, for example,  drilling holes in logs for bug hotels.  You can follow Prof Goulson on Twitter or Facebook. [caption id="attachment_40132" align="aligncenter" width="675"] Bumblebees 'enjoing' a small clump of poppies[/caption] [caption id="attachment_40129" align="aligncenter" width="428"] urban herbicide use[/caption]  

As stated in the previous post, bark is a mixture of living and dead cells.  Cork cells abound, especially in trees like the cork oak, where the cork may be regularly harvested.  This may be used for flooring, insulation and yes - corks for wine bottles. However, bark is a source of many things.  From early times, bark from trees like alder, buckthorn, oak, birch etc were used to make dyes for clothing.  Material from the inner bark of some trees (e.g. lime, willow, mulberry) was a source of fibres for clothing and cordage (string / yarn). Herbalists also found a use for the bark of certain trees.  Infusions of willow were used to treat fevers, the ‘ague’, rheumatic aches and pain.  It contains salicin, which the body converts to salicylic acid, an early 'form' of 'aspirin'. Interestingly, Nicholas Culpeper, in The Complete Herbal (of 1653) gives a number of uses for willow, including to staunch wounds, but does not mention pain control. The bark of the Cinchona [Jesuit’s bark] gave quinine - a treatment for malaria [caption id="attachment_39935" align="alignleft" width="300"] Amber[/caption] When a tree, like a pine, is injured (through storm damage or insect attack), the bark can produce resin - a sticky and viscous liquid.   The resin is produced in resin ducts present within the bark tissue, though the ducts may be present in deeper tissues. Research has shown that ponderosa pine trees that had more (and wider) resin ducts survived drought and bark beetle attack better.  The resin can harden and help seal wounds . Many resins contain terpenes, such as alpha-pinene and limoneme.  The resin from pine and other conifers can under special circumstances be converted into amber.  Sometimes, the resins produced can be fragrant. Trees of the genus Boswellia and Commiphora produce a aromatic resin that gives frankincense and myrrh respectively.  Both are produced by the wounding of a tree so that its resin seeps out.  Both may be used in the making of incense. Another bark exudate comes from certain species of Acacia - Gum arabic, which forms from the hardened sap (adjacent image).  Acacia species belong to the ‘Bean’ family (Fabaceae).  The gum is collected from trees, mostly in Sudan and the Sahel.  Gum arabic is a mixture of glycoproteins and polysaccharides.  The polysaccharides are constructed from the sugars arabinose and galactose. It is soluble in water and edible, and has a number of uses in the food and pharmaceutical industries. Tapping or wounding the bark of different trees can result in various fluids being released, for example, latex.    White or yellow latex is produced by the rubber tree (Hevea brasiliensis).  The latex is found in special vessels within the bark - laticifers. The process of tapping rubber trees is outlined in some detail here.   Latex production is not confined to woody trees, small herbaceous plants like dandelion and spurge can produce a white, milky latex (as can the opium poppy). [caption id="attachment_39984" align="alignleft" width="300"] Euphorbia latex[/caption] The latex produced by some members of the Spurge family can cause burning pain, inflammation or even blistering - for example that of the Pencil tree.  Such toxic saps most likely evolved to deter animals from grazing. Sometimes, a watery sap may be collected from the bark.  This is the case with Birch.  Sap may be collected (tapped) in early Spring, when sugars and other materials are being mobilised for growth, leaf production etc.  Sap may be collected later but is said to then have a bitter taste.  The sap is an interesting ‘cocktail’ of amino acids, protein, sugars (glucose & fructose), betulinic acid, proteins, vitamins C & B, and minerals.  It is used to make a much favoured drink in Northern Europe and should be consumed within days of collection.  Birch trees are quite sensitive to tapping. Not watery, but very sugary is Maple Syrup. Maple trees are tapped by drilling holes through their bark and into their trunks. Starch is stored in the trunks and roots before winter, it is then converted and mobilised in late winter / early Spring. The collected  sap (through tapping) is then heated to produce a concentrated syrup. Thanks to Montemari at Pixabay for image of gum arabic

Trees for a longer life? Researchers from US Forest Service has completed a survey of tree planting in Portland, Oregon and concluded that the more tres are planted in an area, the longer people live. The Portland “Friends of Trees” have planted some 50,000 oaks, dogwoods and other trees around the city over the last thirty years.  After adjusting for factors such as race, income, age and education, the team found that where more trees had been been planted, fewer people died.    This was true for all areas - wealthy or less so. Furthermore, as the trees aged, the mortality rates of the people nearby went down.  Trees generally improve air quality and moderate extreme high temperatures.  A recent report in the medical journal The Lancet suggested that many of the premature deaths from the 2015 heat wave in Europe could have been avoided with 30 percent more tree cover. Birds in decline. UK bird populations are in decline.  Much of the decline occurred in the 1970’s and 80’s, and was particularly noticeable in populations of farmland and woodland birds.  However, the losses have continued in recent times, with a 5% decline between 2015 and 2020. Again, woodland birds have fared poorly with a 12% decline in this period.   The steepest decline in population numbers are seen in species such the Tree Sparrow, Willow Tit, Lesser Spotted Woodpecker and Nightingale.  These have all declined by 90% or more since the late 1960’s. The Turtle Dove shows the biggest decline of any species. Habitat loss is thought to be the main driver of population decline for many species, but oil and plastic pollution are also factors, as is disease - such as trichomonasis and avian flu  Certain species typically associated with urban areas / habitats (Swift, House Martin, Starling and House Sparrow) are also declining. Predation by cats might be a factor, the Mammal Society estimates that cats in the UK catch some 92 million prey items over Spring and Summer, of which around 27 million are birds. Disease such as avian malaria is another factor, one study found 74% of sparrows were infected with the parasite Plasmodium relictum; the changing nature of urban gardens may also be a consideration.  Bees and sunflower pollen grains Bees and bumblebees are struggling with various parasites /infections.  One parasite is the gut pathogen Crithidia bombi.  This is known to affect the ability of bumblebees to create a successful colony. Previous studies have indicated that the the gut microbiome of the bees can help protect against infection by this parasite.  Now a study at the University of Massachusetts Amherst has found that sunflower pollen can help bees resist infection.  It was not known why sunflower pollen was effective, it could be that the shape of the pollen grains was important or the chemical makeup within the grains, or a combination of the two. To test the ‘anti-parasitic nature of the pollen’, an experiment was set up so that some bees received the outer shell of the sunflower pollen (the sculptured exine), whilst another group received the materials from the centre of the pollen grains (but no outer coverings), and a third group received whole pollen.   Bees that received whole pollen grains or just the spiny shells had far less of the parasite in their gut compared to those eating the ‘soft centres’ .  The pollen grains and pollen shells reduced infection by 80 to 90+%.  So it is the spiny shape of the pollen grains that is important in reducing infection in the bees.  'Physical removal' of pathogens is known in other animals, for example, great apes infected with certain nematodes or tapeworms will consume bristly leaves.   These 'irritate' the gut and increase the expulsion of the parasites.