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Seed dispersers.

Seed dispersers.

by The blog at woodlands.co.uk, 10 January, 2024, 0 comments

Many organisms help to disperse seeds in woodlands or forests, from squirrels, birds, bears, foxes, rabbits.  The fruits / seeds may be eaten and pass through the gut of the animal or may be caught in their fur, or stuck to them (like the seeds of mistletoe or cleavers).  However, there is another 'army of helpers'  - ANTS.  Ants may disperse seeds in two distinct ways.  The first way is  through the activity of harvester ants.  Like squirrels and other ‘gatherers’, harvester ants move through the wood or forest gathering seeds and transporting them back to their colonies.  As they transport the seeds, some get dropped or lost on the way.  Others may be ‘cached’ / stored,  in or near the colony for later consumption, but then are ‘forgotten’.  Such seeds may later germinate and establish themselves somewhere away from the parent plant.  This accidental dispersal is sometimes referred to  as  ‘seed predation’. a second method of seed dispersal by ants involves a more intimate association between particular plants and specific ant species.Some plants, when they form the seed, produce an 'extra structure', attached to the seed; an ELAIOSOME or fat / oil body.  This elaiosome lures or attracts ants to the seed.  Wood anemone and cow-wheat (Melampyrum pratense) seeds have an elaiosome. [caption id="" align="aligncenter" width="512"] cow wheat ; thanks to Kristian Peters -- Fabelfroh 09:39, 3 October 2006 (UTC), CC BY-SA 3.0, via Wikimedia Commons[/caption] Ants need some fat, and fat-rich food is hard to come by in the woodland setting.  The ant carries off the seed to the colony, where the fat body is eaten (often by the ant larvae).   The seed is then left and can later germinate. This interaction between plant and ant is termed  MYRMECOCHORY. It is a form of mutualism, as there are benefits to this arrangement for both ‘partners’. The seeds of the plant are ‘protected’ from seed predation by birds and rodents.   The seed is dispersed from the parent plant, ants bearing a seed for some 70 metres have been recorded.  The seed is then (often) deposited in a nutrient rich microhabitat. The ant gains a ‘tailor made’ food material rich in fat, an energy rich material.  In some areas, such as Australia, the seed may be protected from fire as it is buried at some depth. Myrmecochory is seen in many species in north eastern America, but also Europe, Australia and Africa. wood ants https://www.youtube.com/watch?v=ZVGcl4Om-C8&t=40s    
Woodlands Web Notes : 30

Woodlands Web Notes : 30

by The blog at woodlands.co.uk, 1 January, 2024, 0 comments

Willow bark and the covid virus. The Covid pandemic created great strains on health and business services, and the virus continues to impact society in many ways.  It is not surprising that there is an ongoing search for anti-viral agents. Finnish scientists have found that willow bark may have a role to play. Willow bark has been used as a natural medicinal product over the centuries as an effective agent to treat pain and inflammation.  The anti-inflammatory properties of the bark are generally ascribed to salicin, which was to lead to the development of acetylsalicylic acid, that is aspirin.  The Finnish scientists ground up the willow bark in hot water and then sieved it to create an ‘extract’.   This solution was then added to a number of cell cultures that were exposed to different viruses (enteroviruses, a seasonal coronavirus and SARS CoV2).  They then monitored the viral activity, cell infection and viral replication  The extract had an effect on all of the viruses.  In some cases, the extract affected the envelope of the virus (a structure surrounding the viral genetic material) so the viruses essentially broke down, whereas others were prevented from releasing their genetic material and reproducing.  Specifically, though the Covid-19 virus could enter cells when treated with the extract, it could not reproduce once inside. The research team analysed the extract’s chemical composition and tested some known constituents of bark but concluded the success of the extract probably resulted from the interactions of different biologically active compounds.  Compounds in the extract included many complex chemicals (for example, hydroxycinnamic acids, salicylates, flavonoids, flavan-3-ols, and proanthocyanidins (polyphenols).  Further work will focus on the role / interactions of these various compounds. The Hazel Dormouse in peril. The numbers of the hazel dormouse have fallen dramatically since the turn of the century.  The dormouse has disappeared from Staffordshire, Northumberland and Herefordshire in the last few years.  This loss is attributed to The destruction / fragmentation of their habitats Poor management of woodlands and hedgerows, leading to a loss of diversity / niches Rising deer numbers, feeding on saplings and shrubs Extreme weather patterns may also play a part Captive-bred dormice have been re-introduced to some 25 sites in 13 counties across the country, sadly nine of these reintroductions were not successful.  Dormouse bridges have been created to enable the animals to move between areas dissected by major roads (such as the M1), others are planned.   The dormouse (Muscardinus avellanarius) is a nocturnal animal and lives mainly in deciduous woodland,  it feeds among the branches of trees and shrubs. the dormouse rarely descends to the ground.  It feeds on a wide variety of 'foods' ;  flowers (nectar and pollen), fruits (berries and nuts), certain buds and leaves and some insects, such as aphids and caterpillars. The hazel dormouse is regarded as a ‘flagship species’, that is to say, if the dormice are thriving then it is likely that other species are too from butterflies to birds such as the nightingale.  Dormice are currently assessed as ‘Vulnerable’ to extinction in Britain under IUCN Red List criteria, but recent studies suggest a classification of ‘Endangered’ might be more appropriate.  Certainly, their future is uncertain. Detailed information on the hazel dormouse is available at PTES (note this link opens a PDF).  Their report details the state of hazel dormice in 2023. zsaqwa https://youtu.be/4u-yMkXOuTY Changes in the Boreal Forests. Boreal forests encircle the northern reaches of the Earth, lying just below the treeless under of the Arctic.  These forest cover large areas of Alaska, Canada, Scandinavia and Siberia.  These forests contain billions of trees, most are conifers but birch, poplar and aspen may also be found.  The trees (and soils) contribute significantly to the cycling of carbon in nature, absorbing carbon dioxide in photosynthesis. They are also home to many species of migratory birds, plus predator species such as lynx and brown bears, and wandering herds of moose. Due to the remoteness of these forests, they have remained (until relatively recently) unaffected by human impact.  Now these forests are warming at a rate above the global average.  This has a number of effects:  In the southern parts of the boreal forest. Conditions are becoming too warm for cold adapted trees; their growth is slowed and they may die. With the warming comes increased dryness, which leads to water stress and increased risk of insect attack /  infestation. The dryness also means that forest fires are more likely and occur with increased ferocity.  This year, the fires in Canada have been particularly extensive and damaging.  Some 18.5M hectares went up in flames.   The plumes of smoke spread far and wide. [caption id="attachment_40597" align="aligncenter" width="675"] Canadian forest fire[/caption] Scientists are now using satellites to track changes in the extent of the boreal forests.  If trees are being lost on the southern edge of these forest, then it might be expected that the northern limit for tree growth might change.  Indeed, there is some evidence for this in Alaska where young Spruce are now growing some 25 miles beyond the previous tree line, moving into the ‘treeless tundra’.  It may be the loss on the southern edge is compensated by extension of the most northern parts of the boreal forest, but it is not clear whether tree can ‘move’ at the rate of climate change.  
Spicing up Christmas.

Spicing up Christmas.

by The blog at woodlands.co.uk, 24 December, 2023, 0 comments

What do nutmeg, allspice, vanilla, cinnamon, anise, cloves, ginger, and cardamom generally have in common ? Broadly speaking, they are spices that we associate with Christmas. They are much used in cakes, christmas puddings, mince pies, mulled wine, and punch. They add nuance and flavour to eating and drinking at this time of year.  Whilst spices are parts of plants, ‘spices’ is not a strict botanical term, more a culinary one. Spices come from a variety of plant sources, ranging from woody shrubs and trees, to the roots, flowers, seeds and fruits of herbaceous plants.   Spices are generally dried plant products, whereas other flavourings notably herbs are used in their fresh state. Spices and herbs offer sensations such as pungency, hotness, freshness as well as feelings of temperature or even pain (think of a very hot chilli pepper or curry).  Apart from the fact that people across the world enjoy the taste of various spices, various hypotheses have been put forward to explain the use of spices (for example, the Darwinian gastronomy hypothesis). Nowadays, spices are regarded as familiar or commonplace but in the past they were exotic and expensive (as was tea, which was kept under lock and key away from the servants).  Spices ‘unlocked’ fortunes for those who ‘discovered’ and transported them from far flung places (such as the Dutch East Indies, the source of nutmeg, cinnamon and black peppercorns). The original source of Nutmeg was the Banda Islands of Indonesia (sugar cane also originated in this area).  The Portuguese and the Dutch fought for control of the islands.  The Dutch East India Company was established in the early 1600’s and operated from Jayakarta for best the best part of 200 years.  Britain briefly occupied the islands and nutmeg trees were sent to Singapore, Malaysia and Sri Lanka, and then on to Zanzibar, Grenada and the Indian state of Kerala. As the tree’s (Myristica fragrans) homeland is tropical, it cannot tolerate frost but it is now widely grown throughout Indonesia, India and Guatemala.  Between them, these countries produce some 85% of the nutmeg harvest each year.  Nutmeg trees are dioecious, that is, there are separate male and female trees.  Young trees begin to produce fruit when they are a few years old but it not possible to determine which trees are male and which are female until then.  Obviously only female trees will produce nutmegs.  Peak production of the fruit occurs when the trees are about twenty years old and productivity falls after some 60 years. The fruit is termed [botanically] a drupe.  That is a fruit in which an outer fleshy part (the skin and flesh) surrounds a single shell (the pit, stone) with a seed (or kernel) inside.  The fleshy covering of the nutmeg is sweet and in Indonesian culture may be used to make a jam, juice or dessert.  Beneath the flesh / pulp is a crimson tissue. This is peeled away, dried and grated to form the spice - MACE.   The seed is dried in the sun, the flesh extracted and ground to make the commercial form of NUTMEG, though it can be grated.  Whilst mace and nutmeg are similar in flavour, mace is sometimes described as having a more subtle taste and a bright orange colour.  Nutmeg has a warm, slightly sweet taste; it can be used to flavour baked goods, puddings, potatoes, meats, sauces,, and such drinks such as eggnog (though cinnamon may be used as an alternative ingredient), mulled wine and chai tea. Interestingly, too much nutmeg can have neurological  effects (convulsions, delirium, headaches).  Whilst the chemicals in nutmeg (and other spices) add flavour to our foods and drink, they are actually part of the plant’s defence mechanisms.  They deter insects and other animals from eating / attacking the plant, and may have anti-microbial properties.  Nutmeg contains a compound called myristicin - it protects the seed against attack.  However, in the body this can be converted into the chemical MMDA, an amphetamine derivative,   The effect(s) of consuming large amounts of nutmeg can take some hours to develop and may persist for some time. The levels recommended for use in cooking etc are generally quite safe. Most recipes use between 1/4 to 1/2 teaspoon of nutmeg, and these recipes are then often split into several portions, so the actual exposure to nutmeg (and myristicin) is small. Incidentally, nutmeg was once thought of as a treatment for the plague! Nutmeg is one of the ingredients of mixed spice.  This is a blend of different sweet spices. It often contains cinnamon, nutmeg, allspice; sometimes cloves, ginger, coriander (seeds) and caraway may be added.  The term "mixed spice" has referred to this blend of spices in cookbooks dating back to the nineteenth century and possibly much earlier. Allspice is the dried fruit of the plant Pimenta dioica, an evergreen tree / shrub. Early attempts to grow the tree from seed failed until it was found that the seeds needed to pass through the gut of birds - this was the ‘trigger’ for successful germination.  The fruits are traditionally dried in the sun, they then resemble peppercorns.  At one time, the plant was thought to grow only in Jamaica and it is sometimes referred to as the Jamaica Pepper. Now, it is grown in many warm parts of the world.   Whilst allspice is a valued ingredient in Jamaican cooking, e.g. jerk seasoning, it is also used in many other cuisines : middle eastern, Polish, Finnish and Swedish.  It is used to flavour stews, soups and meat dishes, but can also be used in various sweet dishes.  Allspice is also an ingredient in mixed spice (mentioned above) often used in baking, and in the making of Christmas pudding or a Christmas cake. [caption id="attachment_40700" align="aligncenter" width="675"] Cinnamon[/caption] Historically speaking, another valued spice was cinnamon.  It was a suitable gift at the Temple of Apollo (at Miletus).  The source of cinnamon was a secret to traders in the Mediterranean world for centuries,  they controlled the spice trade in order to protect their profits / monopoly.  Cinnamon comes from Cinnamonum trees that belong to the Laurel family.  There are many species (see here for a list) but Cinnamomum verum known as "Ceylon cinnamon" is considered to be "true cinnamon”. However, most commercially available cinnamon comes from :- C. burmanni  - Indonesian cinnamon or Padang cassia),  C. cassia  - Chinese cinnamon or Chinese cassia),  C. loureiroi  -Saigon cinnamon or Vietnamese cassia), and C. citriodorum - Malabar cinnamon The trees are coppiced so that multiple stems are produced and it is from the bark of these stems that the strips of cinnamon are produced.   [caption id="attachment_40703" align="alignleft" width="300"] cinnamon quills / sticks[/caption] Cinnamon has a strong, spicy flavour.  The properties of cinnamon come principally from two chemicals - cinnamaldehyde and eugenol. The cinnamaldehyde is largely responsible for the flavour and aroma of cinnamon.    It is known to stimulate particular receptors in the nerve endings in the mouth - the TRP receptors.   The eugenol has a pleasant, spicy, clove-like scent.  Cinnamon is used in the baking of cinnamon rolls and buns, as it handles baking conditions well.  It is commonly used in Sweden, and such is the ‘importance’ of their cinnamon buns - kanelbullar that the Swedes have an official Cinnamon Bun Day - on October 4th!   Cinnamon is also widely used in Portuguese, Turkish and Persian Cuisine. Cinnamon is also used in fragrant candles.  Thousands of years ago, cinnamon (and pine resin) was used in Egypt as a ‘perfume’ / embalming material in the preparation of dead bodies for mummification.  In recent times, cinnamon-rich materials have been investigated for medical uses, particularly in relation to type 2 diabetes and the control of blood sugar levels. Thanks to pixabay for images of nutmeg .
Ginger, gingerbread and ginger tea.

Ginger, gingerbread and ginger tea.

by The blog at woodlands.co.uk, 15 December, 2023, 0 comments

In previous years, the woodlands’ blog has looked at various seasonal foods, such as the Christmas pudding, the Christmas lunch and the seasonal spices.  However, one seasonal flavour that has escaped our attention is ginger. Gingerbread men, gingerbread houses are now very much part of Christmas celebrations in many parts of the world.  The gingerbread house probably dates back to C18th Germany, and associated with the brothers Grimm tale of Hansel and Gretel.   Setting time aside at Christmas to build a gingerbread house is a particularly Swedish tradition. Gingerbread biscuits in the form of people may go back to the court of Queen Elizabeth, where they were made in the likeness of important guests.  In Bergen (Norway), volunteers build a gingerbread town, this is called the Pepperkakebyen,.  buildings, trains, carousels, ferris wheels and scenes from Bergen are made in gingerbread form. Ginger comes from the fleshy root, actually  the  rhizome of Zingiber officinale, [a rhizome is an underground stem].  The plant is a herbaceous perennial which grows to a height of approximately one metre with  narrow leaf blades. Ginger belongs to flowering family Zingiberaceae, which includes turmeric and  cardamom.  Ginger originated in Southeast Asia, it was grown in China and then moved across that part of the world and found its way to Europe with the Spice Trade.   [caption id="attachment_40708" align="aligncenter" width="678"] fresh ginger [/caption] [caption id="attachment_40741" align="alignleft" width="300"] three ginger teabag[/caption] In the western world, it was possibly first used by the Greeks, then the crusaders brought some back with them but it was not until the mid 1600’s that ginger and other spices became more generally available, although expensive.  As a spice, ginger is now easily found in powdered form in supermarkets but fresh ginger root is also available.  The ginger root contains a large number of chemical compounds; zingiberene makes up some 30% of the root’s essential oil, other compounds include  ß-sesquiphelandrene and ar-curcumene.  When the root is sliced up and infused with hot water, a ginger tea is the result.   Ginger in various forms has been used in traditional and alternative medicine, it may aid in digestion and reduce nausea and has been recommended to help with morning sickness in pregnancy. There is some evidence that ginger may help with weight management and possibly arthritis. Ginger with cloves, nutmeg and black pepper combine to make ‘quatre épices’, which was used in sausage making.  All four spices contain antimicrobial compounds, which would help stave off bacterial growth.  At this time of year, Ginger is often used with other spices, for example, cinnamon. The two may be combined in a tea or used in the making of biscuits / cookies, including the traditional gingerbread men for Christmas.
Last tree standing ?

Last tree standing ?

by The blog at woodlands.co.uk, 2 December, 2023, 0 comments

Just as many animal species are threatened with extinction, so are many species of tree.  In fact, one estimate suggests that up to a third of tree species are under threat - that is more than 17,000 species.  This equates to more that the number of endangered mammals, birds, reptiles and amphibians put together.  In 2021, the IUCN (the International Union for the Conservation of Nature) produced a report on some 58,497 tree species which identified 17,510 species as being threatened (and 142 extinct in the wild). In Mauritius, some 57% of tree species are at risk of extinction! Ideally, no single tree species should be lost, a single species can be an integral part of an ecological network. Its loss could result in the disappearance of many species and even an ecosystem collapse.  Some tree species are now represented by single numbers of specimens.  The ‘lonesome palm’ (Hyophorbe amaricaulis) is probably the last surviving member of its species. It is to be found in a botanic garden in Mauritius. It is an old, damaged and spindly specimen. It has problems with fruit formation; each of its fruits contains but one seed and the seeds are difficult to germinate (even the botanists at Kew could not persuade them to grow). The best approach to saving vulnerable trees is to protect their natural habitats.  This might mean controlling grazing by herbivores, or banning logging in sensitive areas.  Sometimes a change in cultivation techniques can make a difference.  The Lansan Tree produces a valuable, aromatic resin.  It is endemic to the Windward Islands and its fleshy fruits provide for native pigeons and other wildlife.  The resin is collected (tapped) from the tree by slashing the bark every one-to-two weeks. However, over-tapping for the resin can lead to the trees becoming infected with pathogens, then rotting, or subject to termite attack. The pathogens may spread to untapped trees.  Unregulated tapping and conversion of land from rainforest to agriculture have led to Lansan Tree populations all but disappearing in places. On Saint Lucia, where there is a large but threatened population of Lansan Trees, there is hope after the introduction of a sustainable resin harvesting technique.  This technique does not damage the tree but still allows a good yield of the resin.  This,  coupled with training of licensed resin tappers should protect the trees. Some species have reduced populations because their pollinators have been lost, so fruit and seed production has ceased.  Other species have separate male and female plants (dioecism) and the small populations that remain are represented by only one sex.  This was true for the catkin yew population in Hong Kong, where all the trees were males.  A global search found a female specimen in the Royal Botanic Garden in Edinburgh.  Cuttings from the Edinburgh tree have now been planted in a managed site in Hong Kong.  Hopefully when they flower, fruit and seed production will occur;  but it may be a long wait for the young trees to reach sexual maturity.  Another species, the oleander podocarp (Podocarpus neriifolius) has been nursed back to viability by similar techniques. Some rare and isolated trees produce seeds but getting them to germinate is another matter.  Many seeds enter a state of dormancy and have extremely specific requirements for them to germinate and grow on.  In many cases, their needs are simply not known.  The seeds may need a particular temperature regime, or exposure to cold, fire, smoke or light of a particular wavelength. Some seeds may need to travel through the gut of a particular animal before they will germinate.  Sometimes, scientists have used to embryo culture. The embryonic radicle (root) and plumule (shoot) is extracted from a seed and then grown in a sterile nutrient culture medium.  This technique was used at Kew with the ‘lonesome palm’ as attempts to grow its seeds had failed.   Embryo culture resulted in plantlets forming but after a while their roots turned brown and the young plants died.  There are success stories.  A Cypress species Widdringtonia whytei, was reduced to a few trees in Malawi, as a result of illegal logging for timber. Many seedlings have been  planted on Mount Mulanje and  a good number of these have survived. [caption id="attachment_25196" align="aligncenter" width="675"] Entrance to the Millennium Seed Bank[/caption] When and where seeds are actually available, they can be dried or frozen (cryopreservation) and placed in seed banks, for example the Millennium Seed Bank at Wakehurst Place.   We have to hope that through various interventions, the use of seed banks, botanic gardens and arboreta that we will be able to save many rare and threatened tree species,  you never know when one might be needed.
capercaillie

woodlands web updates : 28

by The blog at woodlands.co.uk, 30 November, 2023, 0 comments

On the Red List! The capercaillie is threatened.  Its numbers in Scotland have roughly halved (between 2010 and 2020).  It was once widespread, but now it is found in the pine forests of the Highlands - notably the Cairngorms National Park.  It is a red listed species. The decline in numbers is associated with poor breeding success, poor weather in early summer when the chicks are developing, another problem is predation by species such as the pine marten, foxes and crows.  The Game and Wildlife Conservation Centre (GWCT) has identified another issue that these birds face - namely collisions with deer fences.     These fences are created to keep deer out of particular areas.  However, when the capercaillie (and black grouse) impact on these fences, they are injured or killed.  Marking these fences, reduces the number of collisions but does not stop them.  Unmarked fences are still killing adult birds.  Marking of these fences or their removal would help with the survival of the capercaillie, though removal would  mean trees and shrubs would be unprotected from deer. Mosquitoes! There are some 36 different species of mosquitoes to be found in the UK, which  are generally harmless (though they bite).  But that may change.  With longer and warmer summers, the UK may become a venue for other species such as the tiger mosquito.   This insect has been found in ‘traps’ (monitored by the UK Health Security Agency) at ports and rail terminals.  This insect is known to transmit various diseases, such as dengue fever.  The mosquito was found in Italy in 1990 and it is spreading on the continent. A species of Culex has also been found in some areas of the Thames estuary - which can spread the West Nile Virus. This virus can result in flu-like symptoms.  Outbreaks have been been mainly in the warmer areas of the Mediterranean, but with climate change and the potential for very hot summers here - vigilance will be needed. Floral defences. Many flowers release a distinctive scent.  The scent serves to attract pollinators like bees and butterflies, or  it may ward off pests that would feed upon the plant.. Many of the chemicals that contribute to scents are terpenes.  Recent research has investigated how these chemicals can affect the growth and development of butterflies - using painted lady butterflies.  These butterflies feed on a wide range of plants and hence are exposed to a variety of scents / terpenes. For these experiments, the researcher (at the University of Centra Florida) used four common floral terpenes  Limonene :  which has a fresh, citrus like smell Linalool. : has a floral scent, reminiscent of lavender Cineole : has a camphor-like smell, slightly medicinal contributes to eucalyptus oil. β caryophyllene : this has a spicy / woody fragrance. Different amounts of these terpenes were fed to caterpillars of the painted lady butterfly, and the subsequent development of the caterpillars was monitored and the size of the adults recorded.  The experiment was also conducted at different temperatures.  Temperature affects scent release by flowers. Higher levels of terpenes has significant affects on the survival of the caterpillars, especially when combined with the higher temperatures.  The caterpillars took longer to enter into pupation when given high levels of terpenes, though the size of the adults that emerged from pupation was unaffected.  If longer and warmer summers become more common, the combined effects of terpenes and heat could become important determinants of development. `
Woodlands web updates : 27

Woodlands web updates : 27

by The blog at woodlands.co.uk, 16 November, 2023, 0 comments

Tree survival and drought. Researchers at the University of California have been working on a method that helps predict whether forests / woodlands can survive periods of drought.  As climate change is altering patterns of snow and rainfall, so periods of drought are likely to become more common. Forests are important in terms of carbon sequestration, that is, they take up carbon dioxide from the air and convert it into sugars, starches etc that are stored in the leaves, branches, stems and roots.  However, in order to assimilate and convert carbon dioxide (in photosynthesis), trees (indeed all plants) need a supply of water.  When water is limited, trees need to make use of their reserve materials.  Just as we make use of body reserves of fat and glycogen when food / diet in inadequate. However, reserves can only sustain a tree for a finite period of time.  If drought persists, the tree reaches a ’tipping point’ and it will die.  The researchers studied a forest in the Sierra Nevada that experienced a period of drought between 2012 and 2015.   During this period, millions of trees died.  The team recorded rainfall, soil moisture and temperature in the forest AND the amount of carbon dioxide that the trees absorbed, and their reserve materials.  They found that the trees were able to maintain function / health after the onset of the drought but with the passing of time, the trees exhausted their reserves and were unable to use / convert carbon dioxide into food.  They had reached the tipping point and died.   The methodology of this study was called CARDAMON (carbon data assimilation with a model of carbon assimilation); it is hoped that it can be used to evolve strategies to enhance forest and woodland resilience in the face of climate change. Pollinators. [caption id="attachment_35902" align="aligncenter" width="675"] hoverfly[/caption] University researchers from the UK and Finland have been trying to determine the most effective pollinators of crop plants, like strawberries (and other fruits).  Plentiful and effective pollinators are needed to ensure a good harvest of the fruits. The researchers studied the pollinators at three strawberry farms through the (long) growing season for the fruit.  They adopted two approaches : They caught the insects that visited the strawberry flowers and analysed the pollen they carried in detail (pollen load and type). They also counted the number of flower visits by the different insects, (a quick way to identify key local pollinators). Many insects were identified, including :-  European drone fly :           Eristalis arbustorum Honeybee :                               Apis mellifera Levels drone fly :                   Eristalis abusivus Buff tailed bumblebee :     Bombus terrestris White tailed bumblebee :  Bombus lucorum Common drone fly :             Eristalis tenax Red tailed bumblebee :      Bombus lapidarius Early bumblebee :                Bombus pratorum Bent-shinned Morellia :   Morellia aenescens Hoverflies are true flies, that is, they belong to the order Diptera or true flies, as they have a pair of wings and a pair of halteres (balancing  / orienteering organs used when in flight). Several of the flies in the genus Eristalsis are known as Drone Flies (due to their resemblance to honey bee drones).  The larvae of Eristalis  species are commonly found in putrid / stagnant water and sometimes referred to as “rat-tailed maggots”. It was noted that pollinators also made use of the wild plants to supplement their diets, as strawberries alone cannot meet the nutritional needs of pollinators.  ‘Elsanta’ strawberries have a relatively low sucrose and protein content in both their nectar and pollen. The precise  order of importance of pollinators varied between farms.  Bee (Apis and Bombus) species  and hoverfly (Eristalis) emerged as key pollinators. The European drone fly was the most important pollinator at two of the three farms studied, evidence that hoverflies can be effective pollinators.  One farm had commercial hives of the honey bee but they were less significant than the activities of of the hoverflies and bumblebees. The abundance of a particular insect, coupled with its active period were /  are important determinants of pollinator importance.  Sawdust and plastics - a possible use?. Plastics represent a relatively new, but persistent and major form of pollution (on land, in the sea, indeed everywhere).  Whilst many plastic objects are instantly visible in the form of discarded bottles, fast food containers, many plastic pollutants are in the form of very small particles of plastics  - nano and microplastics.  The concern is that we and other organisms are taking these microscopic particles into our bodies from our food / drinking water. However, it is possible that plant materials may offer some ‘solutions’.  Water that contains micro and nano plastics can be filtered through sawdust that has been treated with tannic acid.   Tannic acid is large molecule, its molecular formula is C72H52O46 .  Tannic Acid is found in certain plant galls (swelling of trees caused by parasitic wasps) and in the twigs of certain trees, such as Chestnut and Oak.  The wood sawdust contains fibres of cellulose, combined with hemicelluloses and lignin.  Water can flow through this material by capillary action.  This plant-based filtration (known as bioCap) of plastic-laden water is capable of dealing with a wide range of nanoplastics (PVC, PET, polyethylene etc), and tests with mice suggest that the filtered water may be sufficiently free of plastic to pose little risk.  

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