At first, you might not notice them, but ants in a woodland are important. Their presence indicates healthy woodland, and the Forestry Commission recognises them as a ‘keystone species’ in the woodland / forest ecosystem and encourages woodland owners to treat them sympathetically.  Ants, like bees and wasps, belong to a group of insects known as the Hymenoptera .  These are insects with membranous wings and narrow ‘waists’. Like bees, ants are ‘social insects’  and within their nests, there is a division of labour (workers, soldiers, queens).    There are four main species of true wood ant - Formica rufa, F. aquilonia, F. lugubris and F. pratensis. Ants are important for a number of reasons, for example :- They help disperse seeds.  They manage pests by preying on herbivorous insects that damage leaves They contribute to nutrient recycling, t Their nests provide a habitat for a whole range of invertebrates that live specifically in wood ant nests. For example, the woodlouse  (Platyarthrus hoffmannseggii), which has ‘lost’ its eyes and colour and is completely adapted to living in the dark recesses of the ants’ nests. They are a source of food for various predators including woodpeckers. Through the building of nests, they affect the soil profile, the drainage and permeability of the top soil, and help with the distribution of various nutrients.  A wood ant colony nest can persist for many years and survives so long as there is a queen / s present.   During the winter months, only queens and a limited number of the workers live on deep inside the nest. Once the temperature begins to rise in the Spring, then workers will begin to emerge and start to forage – and the queen(s) will begin to start laying eggs again.   Fertilised eggs will give rise to female ants, and unfertilized eggs give rise to males.   The males and queens have wings, and are bigger than the workers. The life expectancy of a worker is about 60 days.   Ants such as the southern wood ant [Formica rufa]. build large, ‘thatched’ nests, (see the film link below) which may contain many thousands of workers and queens (up to a quarter of a million). An ant nest is instantly recognisable, it looks like a roughly shaped dome, made from an untidy heap of leaves and twigs – with ant trails leading to and from. The heart of the nest is deep underground, whilst on the surface is the dome shaped ‘thatch’. The thatch consists of a variety materials in the thatch – small twigs, moss, heather, pine needles.   These materials are positioned so that they  not only intercept the sun’s rays to help warm the nest  but also are laid in such a way that water / rain runs away from the nest, reducing the risk of flooding.  Some ant species build their nests in /on gravel or sandy / stony soils - which reduces the risk of water logging. Like many insects, ants make use of pheromones (volatile chemicals). For example, to lay paths to the nest. The study of ant trails and ant behaviour has inspired computer programs / simulations to the “travelling salesman problem”, that is finding the shortest route round a large number of fixed locations (think of the Amazon’s driver’s day!  Woodlands TV has produced another film that focuses on woodland ants.  The film, presented by Giles Pitman, can be seen either on this website or on YouTube https://youtu.be/9wtvwlL2Wzg. Interesting fact : Ants can spray formic acid from their abdomen – when threatened. This smells like vinegar and is thought to be a deterrent to birds or other predators.  

Mason bees and agrochemicals The blog has reported many times on the threats to bees - money bees, bumblebees and ‘wild bees, such as mason bees / solitary bees.  The threat to bees from neonicotinoids has been well documented, now there is a report that suggests that certain other agrochemicals may be harmful to bees. Researchers at the Julius Maximilians University at Würburg have been investigation the effect of a fungicide (Fenbuconazole) on the reproductive behaviour of horned mason bees (Osmia cornuta).  A number of Osmia species are used to improve pollination in fruit and nut crops.    They are efficient pollinators having a special pollen collecting / carrying structure called a scopa.  Mason bees are solitary bees.  Each female is fertile and makes her own nest and no worker bees for these species exist. In the Spring, male and female bees emerge from a nest.  The males generally exit first and remain near the nest, ready to mate with the females.  A female bee selects a mate on their ‘smell’ / odour and the ‘quality’ of their thoracic vibrations (achieved through muscle contractions).  After mating the males soon die.  The females search for and select a nest site, visiting flowers to collect pollen and nectar for their nests.  Once a certain amount of food has been collected within the nest, the females lay their eggs on top of this material (in a series of cells) and then seal off the nest.  The eggs hatch to form larvae which feed upon the food and within weeks forms a cocoon, in which it continues to develop to an adult. Though the fungicide (Fenbuconazole) is considered to be of low toxicity and the bees were exposed to a sub-lethal dose, nevertheless the Fenbuconazole had significant effects on the bees.  Pesticide exposed males were more likely to rejected by the females, compared to ‘control’ bees that were not exposed to the fungicide.  The thoracic vibrations of the exposed males were less powerful / noticeable and the composition of their odour or smell was different. The smell of the bees is dependent on particular hydrocarbon compounds in their cuticle  - their exoskeleton.  It is possible, therefore, that the mating behaviour and reproductive success of these bees is being affected by agrochemicals. Carpenter bees. The microbiome refers to the collection of micro-organisms that lives on or in us, particularly within within the gut. Whilst these micro-organisms are small, they contribute to our health and ‘well being’. They offer protection against pathogens, help our immune system develop, and enable us to digest.  Just as we have a microbiome so do bees.  Scientists as York University (Canada) have been investigating the microbiome of three species of carpenter bees (from North America, Asia and Australia). The term "carpenter bee" comes from their nesting behaviour,  most species burrow into plant material such as dead wood or stems, though a few create tunnels in soil.   Social bees (like honeybees and bumblebees) acquire their microbiome by interacting with their hive or nest ‘mates’. Solitary bees, like the carpenter bees, get their microbiome from the environment as they forage for food.   The researchers found that: The bees’ microbiome contained Lactobacilli, which are important for good gut health, helping protect against fungal pathogens and facilitating nutrient uptake. They also discovered crop pathogens in the microbiomes of the carpenter bees which were previously only found in honeybees. Whilst these pathogens are not necessarily harmful, it is possible that the wild bees could be vectors for spreading disease.  With thanks to Pixabay  (Umsiedlungen and Sabinem34) for the above images of bees Finding flowers. Research at the University of Exeter has shown that bees can distinguish between various flowers through a combination of colour and pattern.  This selectivity is achieved despite the ‘acuity’ of a bee’s vision being quite low (about a 100 times lower than ours) - this means they can only see the pattern of a flower when they are quite close (a matter of centimetres).  The researchers analysed a significant amount of data on plants and visiting bee behaviour, and they used experiments involving artificial shapes and colours.  One particular finding was the importance of the contrast between the outside of the flower and the plant’s foliage.  This seemed to help beesfind their way to the flowers quickly .    

Many plants have a distinctive scent, think of sweet peas, jasmine or honeysuckle, or stand next to a pine tree on a warm, summer’s day.  The scent is due to the release of volatile organic compounds (VOC’s, often oils), produced by specific tissues or glands.  Often it is the nectaries within flowers that produce the scent, apart from their ‘job’ of producing the sugary nectar.  The nectaries may be found on almost any structure within a flower - petals, sepals, stamens, ovary*. The location of nectaries varies from species to species.  There are other structures that can produce scent, for example, trichomes, and osmophores. Osmophores are clusters of cells specialising in scent production.  Any part of a plant can release scent, for example, the leaves of eucalyptus, lavender or myrtle. The scent of a plant may include a variety of VOC’s, indeed there may be dozens of different organic compounds contributing to a particular scent.  Many of these compounds are terpenoids (isoprenoids).  They contribute to the scent of eucalyptus oil, lavender oil and the flavours of cinnamon and ginger. Scent may have a number of functions.  It may be released to attract specific pollinators - moths, butterflies, bees, hoverflies etc. (who have learned to recognise the scent).  The production of VOCs can be modulated, for example,  scent production may be turned off when a flower is pollinated.  A scent may also unfortunately be a signal to herbivorous insects to ‘come and feed’. So, scent have positive or negative effects. A scent may be produced to deter herbivory by certain insects.  Sometimes, plants have a different approach. For example,  when pollen beetles feed on oil seed rape, the rapeseed releases VOCs which attract the attention of other insects.  Specifically, those that will lay their eggs in the larvae of the pollen beetles. These insects are usually from the same family as bees, wasps and ants - the Hymenoptera (insects with membranous wings and a ‘narrow waist’).   The pollen beetle larvae are then ‘eaten’ from the inside by the developing parasitoid larva.  The release of VOC’s is affected by a number of factors temperature, light, circadian rhythms, physical damage and drought.  As the temperature increases so the amount of VOCs released increases (usually). This may be experienced in coniferous woodland.  Conifers give off a variety of volatile oils (i.e. biogenic VOC’s) that contribute to a unique aroma and the formation of aerosols found in the air in and around such woodlands and forests; it is most noticeable in warm weather.  [An aerosol is a ‘mixture’ of very small particles (solid or liquid) in air; other examples of aerosols include mist, cigarette smoke, or car exhaust fumes]. In snapdragons, the most scent is emitted at noon which tends to coincide with pollinator activity, in contrast tobacco plants scent release is in the evening / night when hawkmoth are active.  Drought reduces the ability of plants (like rosemary and thyme) to produce / release VOC’s, this in turn, has been observed to affect which pollinators visit their flowers.  Nectaries located within the flowers of a plant are sometimes referred to as nuptial nectaries, whereas those found in other parts are termed extra-nuptial.  

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 !  

Gill Perkins is one of those people you can't help liking - there's a smile in her voice when she speaks and we found her to be generous with her time and knowledge.  She arrived early for our woodland meeting and had come equipped - a small plastic tube with a plunger (costing about £5) allows her to catch bumblebees as they graze on flowers and she can trap them for long enough to tell us that "this one's a queen of the buff-tailed type and you can see she's very freshly minted as her wings are so undamaged ... a lovely specimen ...".    She releases the bee and it seems quite unphased as it quickly goes back to collecting nectar. Gill loves to get out into the woods and see the bees first-hand - most of the rest of the time she's in her office with the 40 or so staff employed by the Bumblebee Conservation Trust, and despite being the Trust's CEO she's often teaching groups about bumblebees and working with various sponsors including a big housebuilder and a big London law firm. Read more...

The latest WoodlandsTV film features some insects that you might see whilst wandering through a woodland this Spring.    One of the earliest to be seen, possibly even in February, is likely to be the bumblebee, which in recent years, has often seen mild periods.  However, the bees may suffer if there is then a particularly cold spell - such as The Beast from the East, which occurred in late February / early March of 2018. Bumblebees and solitary bees are important pollinators. The woodlands blog has often written about bumblebees and the threats that they face due to viruses, pesticides, and habitat fragmentation.  Another woodlands insect - the bee fly is a parasite of their young (larvae).  Read more...

At this time of year, it is unusual to see bees flying around, but one that you might see is the ivy bee; the ivy bee is a ‘new bee’.  It was first described as a distinct species in 1993.  It was present in the Channel Isles,  back in the 1970's (where it is abundant) but was not recognised as a separate species.  In the U.K., it was first reported from Dorset (at Worth Matravers) in 2001.  It has since been found in a number of places along the South Coast – from Kent to Cornwall, and in Wiltshire, Somerset, Surrey and Essex.  It is spreading northwards, and reached the north Norfolk coast (in 2014) and Shropshire;  it has been suggested that the presence of the ivy bee here is another aspect of  climate change.    A map of the areas where this bee is likely to be seen can be found here. Read more...

What’s so special about heather moorland to beekeepers?  Heather is a small plant known scientifically as Calluna vulgaris, or more commonly ling heather.  As the beekeeping season is winding down elsewhere, the small purple flowers that are a characteristic feature of moorland’s stunning scenery are just opening.  The nectar they produce results in a highly sought after and delicious honey, making it worth all the hard work (both on the part of the bees and the beekeeper) that goes into producing it. Read more...