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Viruses, Varroa and honey bees.

Viruses, Varroa and honey bees.

by blogs at woodlands, 2 October, 2021, 1 comments

Honey bees are often infected by the mite - Varroa.  Mites are small arachnids.  The varroa mite is an external  parasite, attaching to the body of the bee and feeding from it.  It also infects honey bees with various viruses, which further harm the bees.  One such virus is the deformed wing virus.  Bees that are severely infected with this virus die within days, some have such poorly developed wings that they cannot properly forage for nectar and pollen.  The virus also affects their ability to learn, so that if they forage they may not be able to find their way ‘home’.  Lost bees die, the colony is deprived of food collected by such bees and the colony may collapse. Eliminating the mite is difficult and the use of chemicals risks contaminating any honey collected from treated colonies / hives.  However, researchers at the National Taiwan University have found a naturally occurring compound that may help alleviate the effects of the virus.  The compound in question is sodium butyrate Na(C3H7COO).  In a series of experiments, the research team found that bees that were fed sugar-water laced with butyrate were better able to resist the effects of subsequent viral infection.  Compared to a control group that did not have butyrate, some 90% were still alive five days after infection whereas 90% of the control group died.  The butyrate treatment also improved the bees’ ability to forage and return to the hive.   Further details of this work here. Sodium butyrate is an inexpensive chemical, and if its benefits are substantiated then it could provide an affordable solution to the mite and virus problem that honey bees face.
Woodlands web updates 7

Woodlands web updates 7

by blogs at woodlands, 2 October, 2021, 0 comments

The British Dragonfly Society has produced a report “State of Dragonflies, 2021”.  Dragonflies display the usual characteristics of insects, three pairs of jointed legs, three clear divisions to the body, compound eyes and a pair of antennae.  They also have two  pairs of (transparent) wings.  The hindwings are broader than the forewings so they belong to the group - Anisoptera (from the greek unequal wings).  They can fly fast and manoeuvre well.  Their ancestors were some of the first winged insects to evolve. The report notes that Many species have increased their distribution (since 1970), for example, the emperor dragonfly,  the ruddy darter. Though some like the black darter seem to be in decline; this may be associated with a lack of heathland management and the drying of blanket bog areas. Several species have arrived in Britain from Southern Europe for the first time, with others returning after long absences.  The vagrant emperor is a long distance migrant from Africa and the Middle East. It is thought that it might now be breeding more regularly in Southern Europe so that some now migrate northwards more often. Dragonflies are moving northwards across Britain and Ireland (associated with warming temperatures and climate change) Whilst the distribution of species has increased, the actual numbers of different species is not known so it is not possible to say if dragonfly numbers have increased overall. However, compared to many reports on the collapse of insect numbers, it would seem that that many dragonfly species are responding to climate warming and an increase in the number of ponds (for example, see the woodlands blog of the restoration of ghost ponds in Norfolk), lakes, gravel pits in recent years. The larval stages of dragonflies (nymphs) are spent in water. Apart from changing the distribution of various animals (and plants), climate change can have other effects.  Some homeotherms ‘warm blooded’ animals (birds and mammals) are undergoing changes in their body form or ‘shape shifting’.  Sara Ryder et al of Deakin University, Australia has studied several species of Australian parrot and has found that their beak size has increased since the nineteenth century:  this increase in beak size is thought to be associated with better heat exchange.  Other research has reported on changes to tail length in wood mice, also tail and leg size in masked shrews.  The changes are generally less than 10% but they do seem to be responses to changing climatic conditions. Pampas grass (Cortaderia selloana) is a tall, clump forming grass with attractive plumes that can find a home at the coast, in town or in your garden.  It was originally a species native to South America. However, it now has a much wider distribution, mainly due to its use as an ornamental plant though it was also used in South Africa to control erosion on dumps around mines. Each plume can produce tens of thousands of seeds.  Consequently, it is now regarded as an invasive species in many countries. It has expanded across industrial and urban areas, squeezing out native species in coastal regions of France, Spain and Portugal, Now the IUCN (International Union for the Conservation of Nature) has introduced a system to recognise the threats posed by harmful species (such as Pampas Grass)  - The Environmental Impacts Classification of Alien Taxa.
opening and closing - flowers, leaves .....

opening and closing – flowers, leaves …..

by blogs at woodlands, 27 September, 2021, 0 comments

Some flowers are open during the day, ready to receive visitors (pollinators) but close up each night at dusk; for example, crocuses, tulips, poppies.  Other plants move their leaves in response to light and dark. Such movements of flowers and leaves are known as nyctinastic movements. The reasons for these movements are not particularly clear / obvious. A number of suggestions have been advanced : The closing of the petals at night might serve to keep pollen dry.  When wetted, pollen is heavier and less easy for insects to distribute. By closing at night, the nectar and pollen is protected from unwanted visitors.  Some insects are nectar robbers that is they take nectar but do not contribute to pollination. Darwin made the suggestion that the closing might help protect the floral organs from the chill of night time temperature. Leaves may move to help capture rain, closing down at night to allow water to trickle down to the roots (?). Different explanations may apply to different plants but these movements have a common underlying mechanism, namely phytochrome.  Phytochrome is a blue-green light absorbing pigment. It responds to red (in the region of 660 nM) and far red light (>730 nM). Red light is generally abundant during the day, but the balance between red and far red shifts towards the end of the day. This change is detected by phytochrome and it directs the plant’s circadian / daily rhythm.  Phytochrome is involved in many processes during a plant’s life cycle from germination to flowering.  The nyctinastic movements of plant parts is, however, largely controlled by the movement of water into and out of cells - cells can swell or shrink.  Some plants have special structures called pulvini to control the movement of leaves.  Pulvini are found in the bean family (Fabaceae), and plants like the sensitive plant (Mimosa pudica) and the Prayer plant (Maranta sp).  Pulvini are usually located on the leaf stalk (petiole). A pulvinus is a small swelling on the stalk, it has a central core of vascular (water-conducting) tissue surrounded thin-walled cells (parenchyma tissue) with large fluid-filled vacuoles.  The flow of water in and out of the vacuoles of these cells raises or lowers the leaf stalk / leaf. [caption id="attachment_36023" align="aligncenter" width="650"] Pulvinus on sensitive plant[/caption] [caption id="attachment_36032" align="aligncenter" width="650"] Young Mimosa pudica[/caption]  
Woodland web updates 6.

Woodland web updates 6.

by blogs at woodlands, 17 September, 2021, 0 comments

Pesticides problems. The effect of pesticides on bees and bumble bees is now well documented.  However, the combined effect of different pesticides is less well known.  If pesticide A is known to kill 10% of the bees in an area that has been treated, and pesticide B kills another 10% then it might be reasonable to assume that 20% of the bees would be killed - IF the effects are additive.  However, evidence is beginning to indicate that the effects of the pesticides is more than the sum of the parts - the pesticides work together / synergistically. Pesticide formulations that are sold to farmers are often ready mixed ‘cocktails’ so exposure to more than one pesticide is often the norm,  so it is important that these co-operative effects are understood and known. Honey bees have been affected by not only pesticides but also varroa.  Varroa is a mite, which lives and feeds on honeybees and their larvae.  Fortunately, bees have complex hygienic behaviours, for example, removing dead larvae or pupae.   Research indicates that honey bees are modifying this behaviour to deal with varroa mites. Helping pollinators Researchers at the University of Freiburg have recently published work establishing the importance of semi-natural habitat regions next to orchards and other agricultural landscapes for pollinators.  Such areas (ditches, banks, overgrown fences etc) help ensure that flowers (and therefore nectar and pollen) are available over a significant period of time.  This is important for pollinators such as hover flies, solitary bees, bumblebees etc. as nectar / pollen provided by crops is only available for a short and limited period.  Such areas are also important for overwintering, nesting sites, providing food for larval stages etc).  Their work focused on orchards near Lake Constance in Southern Germany. Soil remediation with lupins. There are many sites around the world where the soil is contaminated with metals (such as arsenic) as a result of past mining / industrial activities.  Such arsenic contaminated soil might be ‘revived’ by using the natural mechanisms that some plants have evolved to deal with certain contaminants.   The white lupin (Lupinus alba) is an arsenic-tolerant plant that might be a candidate for phytoremediation of soil.  The tolerance of the white lupin to arsenic is thought to be due to the release of chemicals by the roots into the soil.  Staff at the University de Montréal placed nylon pouches close to the roots to capture the molecule released.  The chemicals were then analysed to see which could bind to the arsenic (phytochelatins).  Phytochelatins are known to be used within plants to deal with metals but here they seem to be used externally.  Quite how they work is yet to be determined.
Banner Yellow stagshorn

August Fungi Focus: Yellow Stagshorn (Calocera viscosa)

by Jasper Sharp, 7 September, 2021, 1 comments

Quite remarkably, this is the 50th of my monthly Woodlands fungi blog posts since I began some four years ago with a short piece on Chicken of the Woods. They originally went out unto the heading of ‘Monthly Mushroom’, but this changed to ‘Fungi Focus’ a couple of years back, with my piece on Ash Dieback reflecting how my own interest in the mycological world had moved past the point where the first question I asked when finding a new species was whether it was edible or not.  Instead, the posts were intended to reflect the wider questions I began to ask myself around such ideas as where certain species fit within the wider woodland ecology and what wider purpose they might serve – questions that the more I continue to dig deeper into the subject, the more I realise how much more we still need to learn about this cryptic world.  I’ve also hoped to show that there’s a lot more to fungi than the familiar agaric cap, gill and stem types – a world of crusts, rusts, discs and jellies that also leads into other related areas such as slime moulds. In fact, as I look back over my posts so far from 2021, I realise that only one of the subjects, the Fairy Inkcap, is a conventionally umbrella-shaped one.  [caption id="attachment_35959" align="aligncenter" width="650"] Yellow Stagshorn (Calocera viscosa).[/caption] We are now moving into the peak season for the more eye-catching and recognisable fungi species, and I shall be returning to some more standard mushroom and toadstool examples over the coming months. Before this, however, I just wanted to dwell on a group of jellies belonging to the Calocera genus of ‘Stagshorns’ that have already started coming into their own, although they can be seen pretty much around the year. Geoffrey Kibby’s wonderful Mushrooms and Toadstools of Britain and Europe vol 1 (3rd edition published last year in 2020) lists five biological orders within the broad group of jelly fungi. The Auriculariales include Wood Ears and Tripe Fungus, as well as the two black species encompassed by the name Witches’ Butter, Exidia nigricans and Exidia glandulosa; while similar in form, the two yellow species known as Witches’ Butter belong to an entirely different order, Tremellales – the fundamental difference is that these types are not feeding on the dead wood itself (i.e. are saprotrophic) like the Auriculariales, but are parasitic on the mycelium of other fungi feeding within the dead wood.  [caption id="attachment_35960" align="aligncenter" width="650"] Small Stagshorn (Calocera Cornea)[/caption] The Calocera species belong to a third order, the Dacrymycetales, which also includes the Common Jellyspot (Dacrymyces stillatus) that you might see proliferating all over fences, garden sheds and outdoor furniture in damp weather. (We’ll gloss over the other two orders Kibby lists that contain gelatinous fungi, Agaricomycotina and Sebacinales). Pat ‘O Reilly writes in First Nature that the name stems from the prefix ‘calo’’ meaning beautiful and that the ‘-cera’ part comes from the Ancient Greek for ‘like wax’, as indeed, these beautiful horn-like fungi do have a distinctive waxy texture to them.  Within the Calocera genus itself there are 15 species, although just a few seem to be commonly found in the UK, and only two of these make it into most field guides. But they are all instantly recognisable, not to mention incredibly photogenic, despite their sizes making them surprisingly tricky to get a decent photograph of.  [caption id="attachment_35961" align="aligncenter" width="650"] Yellow Stagshorn (Calocera viscosa)[/caption] Calocera viscosa, commonly known as the Yellow Stagshorn or Jelly Antler, is the type species for this genus – the species that typifies a particular group and which is considered the prime reference point for other species within it. Like the others, it is a bright yellow, with pale orange to red tints appearing in drier weather, although occasionally pale white versions can be found. The reason for the Stagshorn part of the name is fairly obvious. These grow in clumps of branching antler-shaped growths, like vivid yellow corals. They are not, however, related to other coral fungi, like the Ramaria species, which are a lot tougher in texture due to their flesh being the same solid mass of hyphal cells as the fruitbodies of normal mushrooms. The various Ramaria species seem to be a lot less common than the Yellow Stagshorn and in any matter, are not jelly fungi. The differences are easy to discern if you see them side by side than, though rather less easy to describe. If we ignore the superficial similarities, an obvious one is that if you try and take a sample of Yellow Stagshorn, it tends to squash between your fingers and it’s difficult to get home a piece home intact without it squishing or drying out. If you do manage to get to the stage of getting spores samples on a microscope slide, you’ll also notice that Calocera spores are white and more allantoid or sausage-shaped than the brownish more symmetrical ellipsoids of the spores of Ramaria species. [caption id="attachment_35962" align="aligncenter" width="650"] Yellow Stagshorn (Calocera viscosa)[/caption] Another feature that will points towards positive identifications of the Yellow Stagshorn is that they grow exclusively on conifer stumps and dead roots, I found one right at the base of the rare Antrodia carbonica crust fungi I found last summer on a Douglas Fir stump. They are typically not very large, seldom reaching 10cm in height, with several of my guidebooks listing a range between 2-8cm tall. This makes them relatively easy to spot but actually pretty tricky to photograph in terms of getting everything in focus.  That said, they are considerably easier to snap than their relative, the Small Stagshorn (Calocera cornea), which appears in single pointed, non-branching protuberances, usually less than a centimetre in length and about a millimetre in width. You’ll see these spikes spreading almost like hairs across their hosts, the decaying wood of broadleaved trees, particularly beech. Again, quite striking and difficult to miss, but individually difficult to photograph without a macro-lens and, en masse, it is difficult to get everything in focus. [caption id="attachment_35963" align="aligncenter" width="650"] Small Stagshorn (Calocera Cornea)[/caption] Kibby and the authors of Fungi of Temperate Europe list a couple of other Calocera species. The Forked Stagshorn (Calocera furcata) is about the same size as the Small Stagshorn but has bifurcating tips like the larger Yellow Stagshorn, although appears dotted across its substrate rather than bunched at the base. Calocera glossoides grows in small single clubs, and while it doesn’t have a common name listed in the British Mycological Society’s list of English names, Kibby writes that ‘glossoides’ means shaped like a tongue. That leaves one more Stagshorn for our focus, the pallid looking and spatula-shaped Calocera pallidospathulata, or Pale Stagshorn. It is not dissimilar in form to C. glossoides, but it’s gelatinous flesh is pale and semi-translucent at the stem, yellowing at the top. This is a bit of an interesting one, this one, because while it appears to be a lot more commonly found than the previous two I’ve just mentioned, this was not always the case.  [caption id="attachment_35964" align="aligncenter" width="650"] Pale Stagshorn (Calocera pallidospathulata)[/caption] In fact, according to this brief article ‘An alien tale: the history of Calocera pallidospathulata’, the species was only discovered in Yorkshire and subsequently named as recently as 1969. This wasn’t just the first UK record; it was the first record of the species anywhere in the world. How and where it came from remains a mystery, although the article claims that the renowned mycologist and slime mould expert Professor Bruce Ing has conjectured its origins might lie as far afield as Mexico.  Certainly I focussed on a similar case of a fungi taking to British woodlands like a duck to water earlier this year with a blog piece on Crimped Gills. The Pale Stagshorn also seems to have spread rapidly across the UK. In the first decade since its initial 1969 sighting, it had been recorded in a number of locations across the north of England, but made the leap to the south with its first record in the New Forest occurring in 1989. Fungi of Temperate Europe describes its range as “Common in the UK, where probably introduced from North America, but likely to be spreading to other parts of temperate Europe, e.g. the Netherlands; all year.” [caption id="attachment_35965" align="aligncenter" width="650"] Pale Stagshorn (Calocera pallidospathulata)[/caption] I have to say, that while I have yet to come across Calocera furcata or Calocera glossoides, I did find a patch of Pale Stagshorn in a woods near Canterbury a few years back, so I can vouch for the fact that this particular species has spread to East Kent. Not that we should have anything to fear by this seemingly rapid spread. The Stagshorn species all appear on dead wood, and are not harmful in any way to living trees.  Still, it makes one wonder what the processes and mechanisms might be by which more harmful species such as the Ash Dieback fungus might spread across the country.  Supplementary images. [caption id="attachment_35967" align="aligncenter" width="650"] Pale Stagshorn (Calocera pallidospathulata[/caption] [caption id="attachment_35968" align="aligncenter" width="650"] Yellow Stagshorn (Calocera viscosa)[/caption]  
Deer, damage and the pandemic.

Deer, damage and the pandemic.

by blogs at woodlands, 2 September, 2021, 6 comments

Across the UK, there are several types of deer to be found in woodlands and rural areas namely : Red deer Sika Deer Roe Deer Reeves Muntjac Deer Fallow Deer Chinese Water Deer In recent times, the number of deer has increased and it is thought that there might be as many as two million wild deer in the UK - the highest number for many hundreds of years.  Unfortunately, deer can cause substantial damage to trees and woodlands.  Their feeding can cause a range of problems, which can include [caption id="attachment_34910" align="aligncenter" width="650"] Deer damage - bark removal[/caption] Stripping shoots, flower buds and foliage from plants Damage to woody stems, where a deer has bitten part way through the stem and then the shoot is tugged off - leaving a ragged end Eating the bark from younger trees. This mainly happens in winter when other food sources are scarce In addition to the damage associated with their browsing / eating activities, there is also the damage done by male deer who rub their heads / antlers against the trunks of younger trees.  This rubbing may be for scent marking or to remove the outer skin (velvet) present on a new set of antlers.  The antler rubbing results in cuts in the bark. [caption id="attachment_34415" align="aligncenter" width="700"] Remnants of birch woodland near Loch Muick are subject to browsing by red deer (especially in the winter), so temporary fences have been out in place to allow for regeneration and tree guards in place[/caption] Deer numbers are reduced by culling in order to supply restaurants, farm shops, and the hospitality sector with venison.   However, with the onset of the pandemic and subsequent lockdowns / restrictions  the demand for venison dropped significantly (as has price) so very few deer were culled.  Consequently, the number of deer is increasing.  Deer have probably gone through one or two breeding cycles since the first national lockdown,  and numbers are set to increase.   The increase in deer numbers not only affects the trees in a woodland but also plants of the herb and scrub layer.   The loss of plant species and aspects of the structure of the woodland means that particular microhabitats are lost so that species such as nightingales and warblers are at risk. Without careful management of deer numbers, woodlands could become much more ‘uniform’ as deer have no natural predators (in the UK).  It is important that deer numbers are monitored  as they will do significant (most) damage to woodland in Spring as there’s not much food elsewhere for them. Young trees are particularly at risk, unless they are protected.

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