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Blog - September 2022

The European hornet.

The European hornet.

by The blog at woodlands.co.uk, 29 September, 2022, 10 comments

The European hornet (Vespa crabo) is an eusocial insect.  That is to say, hornets live in colonies, with some 200 / 400 individuals in each colony.  A colony is founded by a fertilised queen, who emerges from hibernation in spring. Hornet queens are the sole survivors of an old colony after  a UK winter and they emerge as the weather finally starts to warm in early spring.  They then seek a warm, dry place to start nest construction. Once a nest location has been secured, they lay eggs that hatch into larvae.  The larvae are fed on protein-rich food (chewed up insects) and then they pupate; undergoing metamorphosis [a complete reorganisation of the body].  An adult hornet worker then emerges from the pupa some two weeks later.   These are ‘sterile’ female workers, who take over nest building and collecting food for the next set of developing larvae.   The developing colony lives within the papery nest its a (a bit like papier mâché), adding to the structure as the colony grows.  Twigs, bark and other plant material is broken up, chewed and shaped to form the nest. This material is glued together by their saliva.  Larvae that hatch in the summer are either fertile queens or males.  The males (drones) do not contribute to nest building, food foraging etc.  But in autumn, the males (drones) and the new queens leave the nest to mate.  The fertilised queens hibernate over winter, emerging in spring to start a new nest.  The ‘sterile workers’ and the male hornets die with the onset of winter. In other colonies of social insects, like honeybees, female workers don’t reproduce due to the pheromones that are released by the Queen. This was thought to be the case for European hornets but instead worker hornets enforce ‘sterility’ by physically destroying any worker-laid eggs or the workers laying them ! The food of a hornet is surprisingly varied. They can hunt and capture a wide variety of invertebrate prey (beetles, wasps, moths, dragonflies, robber flies - they may even prey on honey bees).  In many ways, hornets are useful in that they predate on a number of  garden and agricultural pests. Much of this prey is then chewed up to feed the growing larvae.  In return for this material, the larvae willingly ‘exude’ for the adults  a sugary liquid for them to feed on. Adults can also be found feeding on sugar-rich sources such as tree sap, nectar, and ripe fruit. They are more likely to ‘scavenge’ food at the end of summer into autumn rather than hunt.  The head of the insect has dark, prominent eyes, its wings are a reddish-orange, whilst the abdomen is striped with yellow and brown.  Hairs are present on both thorax and abdomen but they are not ‘hairy’ like bumblebees.  The colour of hornets can vary and a number of regional colour forms are known across Europe.  Worker hornets are about 25 mm in length, whilst queens may be up to 35 mm., so significantly bigger than wasps.  Partly because of its colour and size, a hornet can be mistaken for the Asian Giant Hornet (previously reported on in the woodlands blog).  However, a recent report indicates that the european hornet can attack and kill the Asian Hornet, by biting its head off.  Asian hornets are a considerable worry as they attack and kill  honey bees, plus their venom can induce life threatening anaphylactic shock. Breaking news : Asian hornets seen in Essex.   https://www.independent.co.uk/climate-change/news/asian-hornet-uk-bees-insects-b2177217.html In the past, the European hornet was rarely seen in the UK, being largely confined to areas of central southern England, but it has expanded in range in more recent times and is to be found across the South East and even in some more northerly locations.  Female hornets (but not males) have a stinger.  The venom within the stinger contains mixture of various neurotransmitters (serotonin, dopamine, histamine) as well as a concoction of enzymes.  Best avoided !  
Legal highs and illegal lows - are nitrous oxide capsules bad for woodlands?

Legal highs and illegal lows – are nitrous oxide capsules bad for woodlands?

by Angus, 24 September, 2022, 3 comments

As long ago as 1772, it was discovered by the chemist Joseph Priestley that breathing Nitrous Oxide (N2O) could cause interesting effects on the brain - creating a sense of euphoria as well as anaesthesia, analgesia and even amnesia.  More recently the gas has been bottled in canisters and is then transferred to balloons to be inhaled.  Breathing in this gas creates "legal highs" - legal in the sense that inhalation is not illegal although selling "noz" or "whippets" for human consumption to under 18s is illegal.  But they are so popular that one person told me that any party worth attending will have a "Noz Bar" where you can buy canisters to induce their dream-like effects. Indeed these "laughing gas" cylinders became even more popular during the covid lock-downs and became the high of choice, despite the fact that it can be dangerous to take it especially if combined with alcohol or where there is a risk of falling.  Equally disturbingly, the canisters are often discarded and you will often see piles of them outside nightclubs but they are also frequently left on verges and outside woodlands and in public spaces.  To give an idea of the scale of use of nitrous oxide or "noz", it is officially the second most popular drug for 16-24 year-olds after cannabis and according to the ONS 9% of this age group have tried nitrous oxide. It would be hard to completely outlaw the use of these canisters because they are legitimately used in commercial kitchens for making whipped cream - hence the nickname "whippets" - and similar shaped canisters are also used by cyclists for filling repaired tyres.  With the low cost of mass production and large scale imports from China, the wholesale cost of these can be as low as 25p each and they are supplied in large cartons so vast numbers are deposited in the countryside.  It would also be hard to tax these as a technique for reducing consumption but the government seem at least to have considered making illegal their consumption as a recreational drug, but perhaps the biggest driver of consumption is the high profit margins made from reselling these.  A dealer will make a mark-up of 1,000% (ie 10x) and they are low volume so a lot of canisters can be carried by an individual.  Festivals and outdoor events are therefore an attractive place to sell these - so they get into the environment more readily than most containers. These 'silver bullets' of nitrous oxide are designed to be very tough as they contain concentrated gas but the effect of this is that they are almost indestructible and threaten to create a serious nuisance, littering the countryside.  It's possible that these canisters create useful homes for some insects and spiders - a bit like discarded drinks cans and bottles can do, but the effect is surely detrimental to conservation efforts.  Being heavy they are likely to sink into the ground and are hard to collect and they will be a nuisance for gardeners, metal detectorists and foresters.   So, with the rapid build-up of these discarded gas containers into the environment, the question is what on earth can be done about it?         Nitrous oxide has been linked to damage to the nervous system and paralysis.  A recent article details the risks.  
Do foxes bury their dead?

Do foxes bury their dead?

by Angus, 20 September, 2022, 3 comments

Very recently a young fox died in my back garden, so I waited until midnight to remove it.  I was prepared with a garden fork to move it to a derelict piece of land nearby where it could rot away harmlessly, but I got a shock.  The body had disappeared.  I was sure that the fox had been unquestionably dead (no breathing, flies etc) and no human would have disturbed the body.  So what happened?  We know that humans bury or cremate their dead very systematically and with much ceremony, but do foxes bury their dead family members? There are many reports of foxes carrying away other dead foxes, especially young ones but there are quite a few possible explanations.  Maybe they are taken away and eaten - foxes can be cannibalistic - and there are reports of foxes feeding on the corpses of other foxes.  Or potentially the body could have been taken away for burial in order to create a store of food for difficult times.  It seems possible too that older foxes may have taken the body away for a more ritual burial, perhaps partly to prevent the spread of disease.   In Roman times, Pliny wrote that he believed the only animals to bury their dead, apart from humans, were ants.  Ants seem to be genetically programmed to remove all dead and diseased animals from their nests and recent research has shown that honeybees can exhibit hygienic behaviour; this refers to uncapping and removing dead and diseased larvae and pupae from the hive.   Other animals, too, are sometimes reported to bury their dead.  Badgers, who do not make stores of food, have been reported to move their dead from the scene of the death.  Here views differ - some people say that the badgers move these corpses to bury them whilst others say they are just moving the bodies to a more secluded spot in order to feed on them.  Other reports, though rare, suggest that a group of badgers act together in burying a family member. - so-called badger funerals. Foxes are well known for feeding on carrion including the bodies of other foxes.  Indeed it seems that parent foxes occasionally bury young foxes from other groups in order to train their own cubs to dig them up.  They will also raid the food caches of other foxes so they clearly recognise the value of the protein from the body of a fellow dead fox.  So the dilemma remains - was my fox taken by other foxes for food or for a ritual burial?
September Fungi Focus: Hairy Nuts Disco (Lanzia echinophila)

September Fungi Focus: Hairy Nuts Disco (Lanzia echinophila)

by Jasper Sharp, 15 September, 2022, 1 comments

And whoosh, just like that, the whole country changed… After the hottest, driest, summer on record, last Friday the rains finally broke over my parched little corner of the garden of England, transforming the woodlands into a veritable fungal jungle. Much of the joy in going out on regular photographic forays for mushrooms and toadstools for me comes from monitoring the changes in what can be found in specific sites across the seasons. You can head out several times a week and still find things that have popped up since your last visit, while previous finds can disappear without a trace as quickly as they appeared. There’s a definite fear of missing out on some exciting development or potential discovery when I don’t visit my local woods for a while. [caption id="attachment_38908" align="aligncenter" width="675"] Hairy Nuts Disco[/caption] My typical pattern is that I will head out and if I find something new that I’ve not seen yet that season, I will take a photograph of it, recording where and when I first noted its appearance for that year. I generally find around half a dozen or so different species on each trip, but rarely do I return having found nothing, no matter what the time of year, no matter how hot, cold, wet or dry it is. In this sense, I personally find fungi more interesting than plants, in that the number of species in a given wooded environment is far larger but it is very difficult to gauge much of what is there. Whereas the likes of ferns, brambles, bluebells, anemones etc, first emerge and grow relatively slowly, lingering for several months before dying back, most fungi just pop up and disappear within a matter of days. For much of the year they remain invisible as mycelium within their given substrate, with their fruiting bodies popping up in the form of mushrooms and toadstools so quickly that you have to be sure you’re around to catch the moment. Even something as massive and substantial as a Dryad’s Saddle (Cerioporus squamosus), a large bracket reaching up to a meter across with pores beneath and a characteristic hen pheasant pattern on its topside, can come and be gone within a matter of weeks. [caption id="attachment_38909" align="aligncenter" width="675"] The Dryad’s Saddle (Cerioporus squamosus) can come and be gone within a matter of weeks.[/caption] The early autumn period, which marks the beginning of the peak season for mushroom hunters, then, comes as something of a mixed blessing. While it’s hugely exciting seeing fungi that have been hidden underground or within dead wood manifesting their true colours for the first time, it’s almost overwhelming how much new stuff there is to take stock of. My woodland wander last Saturday, 10th September, reacquainted me with a plethora of perennial favourites I’d not seen for many, many months: Green Elfcups, Deer Shields, Oysterlings, Collared Parachutes, and numerous members of the Mycena genus. The most dramatic find, however, was a species that I’d not encountered before UK Fungus Day, on 2nd October of last year, during one of my first explorations of the woods nearby to the new home I’d just moved to, where I spied a tiny cluster of tiny brown cups nestling amongst the spines of a damp chestnut husk lying on the ground. [caption id="attachment_38910" align="aligncenter" width="675"] Hairy Nuts Disco[/caption] This specific host made identification a relatively straightforward matter. I’d found my first ever Lanzia echinophila, blessed with one of the most colourful monickers ever granted by those entrusted with coming up with the English common names listed by the British Mycological Society: the Hairy Nuts Disco. I must have come fairly late to the game last Autumn, however, if the amount I found after last week’s torrential downpours were anything to go by. Vast numbers of these tiny cups sprouted from every single one of the prickly decaying husks covering the ground (the “echinophila” part of its name means “spine-loving”).  [caption id="attachment_38911" align="aligncenter" width="675"] Hairy Nuts Disco[/caption] I’m not sure how common this species might be, as they are don’t seem to be listed in the otherwise exhaustive Fungi of Temperate Europe, but Peter Thompson’s Ascomycetes in Colour describes them as restricted to the rotting cupules of sweet chestnut (Castanea sativa), a tree which dominates the local woodlands of East Kent where it has been traditionally coppiced for use as gate poles and the like. Many of my local woodlands follow the model described in this previous Woodlands post on chestnut coppicing, with oak dotted amongst them, as well as a good number of hazel trees, also once coppiced extensively for use as hop-poles in the hop-growing heartlands of Kent. Many of the mixed deciduous woodlands in the area with chestnut, hazel and oak predominating are now in private hands, and no longer worked commercially, though some still are. [caption id="attachment_38914" align="aligncenter" width="675"] Hairy Nuts Disco[/caption] I would be curious to learn just how common a find Hairy Nuts Discos are across the United Kingdom. I found just one record on the The Fungal Records Database of Britain and Ireland (FRDBI), from September 2017 in Surrey, near Leatherhead, but there are a few more on iRecord, mostly from Sussex and Kent. These kind of things are probably not likely to be registered unless one is actively looking at chestnut husks, something which mushroom foragers in search of edibles are not likely to be doing.  In any case, the cups are relatively small, around 2-3mm in diameter, although can grow considerably larger to around a 1cm across, and the combination of the reddish brown colouration of the fertile hymenium inside the cup and the slightly lighter margins and stalk does make them rather blend in amongst the spikes. There are other small discomycetes fungi (i.e. disc-shaped ascomycetes) that can be found growing on fallen chestnut husks – I mentioned in passing the yellowish Hymenoscyphus serotinus in a post from June on the various lookalikes for fungus responsible for Ash Dieback, Hymenoscyphus fraxineus, as an example of the kind of thing the eagle eyed might spot rummaging around the forest litter.  [caption id="attachment_38913" align="aligncenter" width="675"] Hairy Nuts Disco[/caption] I’m still not entirely sure whether the name, memorable as it may be, describes this species particularly well, as these tiny fruit bodies aren’t particularly hairy, although there is a slightly fibrous texture to the outsides. That said, Hairy Nuts Discos are unlikely to be mistaken for anything else once you know what it is, so if you notice them while scavenging for chestnuts this autumn, please do post a comment here so we might get a better idea of how prevalent they are across the country. [caption id="attachment_38912" align="aligncenter" width="675"] Hairy Nuts Disco[/caption]
The ragwort.

The ragwort.

by The blog at woodlands.co.uk, 12 September, 2022, 4 comments

Ragwort is a common wild flower.  Its common names include, common ragwort, stinking willie and tansy ragwort (though its resemblance to true tansy is rather superficial).  It is not particularly a woodland plant, it is found in dry, open places - on waste land, waysides and (grazing) pastures.  It is not a plant favoured by land owners because it has toxic effects on cattle and horses.  It is generally considered to be a biennial, but can persist for some years. The stems are erect, straight, basically hairless.  The actual plant may grow to a height of two metres.  The leaves are lobed in a ‘pinnate’ fashion and have a distinctive smell that has lead to some of its common names - such as stinking willie.   The ragwort is a member of the daisy family (Compositae, now the Asteraceae), and its flowers are massed together into dense, flat topped clusters.  Each ‘flower’ is made up of many small, individual florets.  In the centre are the disc florets whilst around the edge are the ray florets.  The latter have a large lip or flap, which serves to increase the visibility of the plant to pollinators.  During the flowering season, a plant may produce many thousands of seeds.  The seeds have hairs attached to them, which help in dispersal. Ragwort is a plant that is much loved by pollinators - bees, flies, moths and butterflies.  It is generous in its nectar production, and has been placed in the top ten of nectar producers by one survey.   The plant also provides home and / or a food source for many invertebrate species, some of which feed on ragwort exclusively*, including some species on the IUCN RED LIST.  One species that is reliant of this plant is the cinnabar moth, whose status is described as ‘common and widespread, but rapidly declining”.  Interestingly, the cinnabar moth feeds on the plant absorbing the alkaloids and these make it distasteful to its predators . However, important as the plant is in ecological terms, it is toxic as it contains a number of alkaloids.  These are poisonous to various animals, such as horses and cattle.  The bitter taste is a ‘disincentive’ to much of the plant being eaten.  However, because of the alkaloids, it is one of the five plants (in the UK) named as ‘an injurious weed’ [as defined by the Weeds Act of 1959].  Some people may suffer an allergic reaction after handling the plant, experiencing a form of dermatitis. [caption id="attachment_38929" align="aligncenter" width="675"] Cinnabar moth, image courtesy of mcbeaner on Pixabay.[/caption] Further information on the Ragwortis available on WoodlandsTV, see below [embed]https://youtu.be/esfLW0nIvNo?si=DQ2Uokq7U1pAJYMZ[/embed] [caption id="attachment_38599" align="alignleft" width="300"] Cinnabar caterpillar[/caption] [caption id="attachment_38566" align="alignright" width="300"] Leaves of Ragwort[/caption]  
What to do about saplings in dry weather or in a drought.

What to do about saplings in dry weather or in a drought.

by Angus, 8 September, 2022, 1 comments

If you have planted new trees and there's been a spell of extremely dry weather, as happened in the summer of 2022, you might be very worried for their survival, but there are several things you can do to increase their chances.  This isn't just a problem for the first season because saplings can be at risk for the first three years after planting; it's also not a binary, live or die thing for your planting - usually some trees will survive and some will perish but the challenge is to maximise the percentage that make it through a drought.  Let's first consider how dry conditions affect trees.  The saplings' first response is often to increase root development to take up more water.  Your young plants will also seek to reduce water loss so the leaves will wilt or can even be shed even though it's only July or August, and this can lead to the saplings not having the ability to photosynthesise adequately.  So you need to do what you can to avoid water loss and, if practical, to apply water. So, to increase the chance of your saplings surviving you can, if practical, actually spread water around them but that may have to be done fairly regularly during the period of drought.  Ideally irrigation should happen overnight when evaporation is lower and that will also limit pest problems and "leaf burn" that may be associated with irrigation in full sun. An additional strategy is to weed the young trees thoroughly to reduce the competition for water.  This can be combined with firming up the soil around the base of your saplings to avoid the soil drying out through fissures.  To reduce evaporation and stop the weeds returning you can use a mulch around the base of your young trees - ideally a mulch mat or by spreading some woodchips or bark. A few weeks after the drought has passed but while the leaves are still on the saplings you can assess your losses and order new trees to replace those that have succumbed to the dry weather.  This process is described by foresters as "beating up" but when it comes to the actual planting this needs to be done carefully - only replace trees that you are sure have died rather than those which just lost their leaves early. For urban trees you can be prepared for a period of dry weather by installing watering tubes or bags which reduce surface run-off and make sure that the water reaches the tree roots.   It is unclear how many millions of trees have been lost to the 2022 drought but it certainly includes many mature trees as well as many newly-planted saplings and hedgerow shrubs.  It seems that droughts like this are part of a process of climate change and more such events are probable - so our woodlands will be under increasing stress over the next few years.  For those who are establishing new woodlands a sensible approach would be to plant only a proportion of the area each year and to select a wide variety of tree species.  It also suggests that for new woodlands you should, where possible, include the adopting of areas of natural regeneration - where trees have come up of their own accord - these self-set trees are likely to be very resistant / resilient to periods of extremely dry weather. [caption id="attachment_38870" align="aligncenter" width="600"] Drought - green shoots of recovery?[/caption]  
Toad in a hole

Toad in a hole

by The blog at woodlands.co.uk, 3 September, 2022, 3 comments

Every now and then when sweeping up leaves or tidying in the garden, I am surprised by the sudden hoping of a toad.  The common toad  (Bufo bufo) has warty, olive-brown skin, and short back legs. The toad tends to walk rather than hop (which it does if surprised). Toads are found almost everywhere across the U.K, except for islands like those around Scotland, the Isle of Man and Channel Islands.  They are terrestrial amphibians, returning to water to breed. Sadly, cities and towns pose a threat to toads.   Busy roads often block their migration paths, making it difficult for them to reach breeding ponds. Many toads are killed on our roads each year.  Toads are adaptable and may be found in deciduous and coniferous forests, meadows, parks, scrubland and gardens. They prefer damp areas with plenty of foliage. https://youtu.be/OBFllSNZIdM However, a recent survey into hazel dormice and bats revealed that a number of toads could be found in trees.  Whilst it was known that toads favour woodlands as foraging and entering habitat, it was not known that they could be found in tree cavities (used by bats), or in hazel dormouse nest boxes (some 1.5 metres above ground). One toad was found three metres up a tree. The toads were not found in holes or boxes with other species but it was clear from the study that they would make use of old nests made by dormice or even birds, or natural holes.  The conclusion of the survey was that toads can and do make use of trees, particularly those near ponds or lakes.  Why they climb and make use of trees is not clear.  It could be that  they are searching for food,  trying to avoid predators (hedgehogs, rats, grass snakes, and birds (such as herons and crows), or even  avoiding parasites (such as the toad fly, the larvae of which feed on the flesh of a toad).) Toads generally lie ‘hidden’ during the day., becoming active at dusk. Nightime is spent hunting for the woodlice, slugs, beetles, caterpillars, flies, and earthworms on which they voraciously feed.  It might be that ancient / veteran trees that are known to support a wide variety of animals, may harbour a toad or two.  If you want to report sightings of any amphibians you can use the “Dragon Finder App”.  This enables you to Identify adult reptiles and amphibians as well as their eggs, and larvae.  You can submit your observations and use your smart phone’s GPS function to determine your location or pick from a map.