You may well have heard that bees are in trouble. Domestic honeybee hives seem to die more often than they used to, and some of our wild bees have disappeared altogether; for example, three of the UK’s twenty seven bumblebee species have gone extinct. The big, long-term driver of declines has been farming intensification; where once we had plentiful hay-meadows and chalk downland, rich with flowers, we now have flower-free monocultures of wheat or silage grass. Pesticide use is also contributing to the problem, particularly new generations of systemic, persistent insecticides called neonicotinoids that get into nectar and pollen of both flowering crops and wildflowers. Read more...

Following on from last week's post, the woodlands blog has often reported on the problems facing honey bees and bumblebees - from the vagaries of climate to the effects of insecticides, such as neonicotinoids.  Whilst it is easy to identify a honey bee and spot a bumblebee, it is somewhat more difficult to say what type of bumblebee might be foraging in your garden or woodland. There is a lot of information about bumblebees at the bumblebee conservation trust website.  A particularly useful link is "Top tips for bee ID"; tail colour is an important or helpful feature.  Read more...

DDT was used an insecticide at the onset of WW2, with great success in terms of controlling malaria and typhus among civilians and troops. After the war, it was available as an agricultural insecticide.  However, within a few years, there were warning signs that not all was well and in 1946, the Soil Association journal read as follows "By the wholesale use of powerful insecticides of which far too little is yet known, we may well be upsetting the whole balance of Nature. We are like schoolboys rat-hunting in a munition dump with a flame-thrower." Some years later (in 1962),  Rachel Carson published ‘Silent Spring’ – which seriously questioned the use of organochlorines, such as DDT and warned of the dangers of the indiscriminate use of insecticides.  The use of these chemicals continued Read more...

The Bumblebee Conservation Trust, based at Stirling University, needs your help in recording sightings of bumblebees. They would like you to record what species you see, where and how many, and take pictures of any unusual specimens. Go to http://www.bumblebeeconservationtrust.co.uk/surveys.htm to find out how to take part. Read more...

Bumblebees are regarded as nice, gentle creatures; even their buzzing has a placid, reassuring sound. They rarely sting and are important pollinators in orchards, on farms and in our gardens. Sadly, however, they are under threat. Many species of bumblebee are on the decline and have been, according to some authors, since the late 1950’s. Their decline is often attributed to the introduction of intensive agricultural techniques. For example, Read more...

Last week's woodlands’ blog talked about the fall in insect numbers across the UK.  This is not just a UK problem, it is far more widespread.  Insects,  bees and bumblebees as pollinators aside,  are important in ecosystems;  there are armies of other insects that are providing ‘services’ for us. When a tree dies in a woodland, bacteria and fungi are important agents in the decay of the tree and the recycling of elements, but they are assisted by beetles. If the dead tree was a veteran, during its lifetime it will have provided  a variety of micro-habitats.  Holes and crevices would have been used by bats,  birds,  insects etc.  Now, the the decaying wood will be support different organisms, from microbes to larger fungi, such as bracket fungi that can erupt from surface of the dead tree.   As the wood decays,  the material may become a ‘home’ for saproxylic beetles. For example, Stag beetle larvae feed on decaying wood (building up fat reserves, which the adults later rely on. it adds humus and fertility to the soil as its nutrients are released. Though bees and bumblebees (members of the order Hymenoptera) are important as pollinators (of many fruit and crop plants, so are the hoverflies key to  the pollination of many wild flowers.  Hoverflies belong to a different group of insects - the Diptera. There are several thousand hoverfly species spread across the world. They are found on every continent with the exception of Antarctica.  Work by Dr. Wotton and his team at Exeter University suggests they are situations where hoverflies may be more effective pollinators than bees and bumblebees, and the role of hoverflies in crop pollination may have been under-estimated.  Hoverflies can carry pollen over considerable distances, and may  visit isolated plants.  The common drone fly (Eristalis tenax) has been known to travel some 100km and carry the pollen of eight plant species.  Hoverflies (or Syrphidae) are also known to migrate over considerable distances.  The female marmalade hoverfly can migrate from Scandinavia to Spain and North Africa, migrating in the autumn to lay their eggs.  In the following Spring, succeeding generations migrate north again.  Some American hoverflies are known to migrate from Canada to the southern states. Insects are not just important in terms of facilitating decay or aiding pollination, some are involved in seed dispersal.  Scientists at Kobe University studied the dispersal of seeds from the fruit of the silver dragon plant.  Using  time lapse photography techniques, they watched to see which animals feed on the plant’s fruit at night. Whilst crickets (order : Orthoptera) ate much of the fruit, earwigs (order : Dermaptera) and woodlice (not insects, but terrestrial crustaceans) also consumed significant amounts of the tiny seeds of the fruit.  Further work demonstrated that many of the seeds survived the passage through the gut of these animals.  So apart from being seed predators, small invertebrates may also help their dispersal, depositing them away from the parent plant. Woodlice are interesting land based crustaceans that generally feed on dead and decaying plant material, helping in the recycling of nutrients. Further examples of the importance of insects in nature can be seen in fig production.  The fig wasp 'gives its life' in the process of pollinating the fig, in return the fig provides a safe ‘nursery’ for the young on the wasp, seed the woodland blog on the fig.  There are many types of fig and each has its own wasp, to ensure successful pollination.  Full details of the life cycle of fig wasps can be followed here.  The association between the wasps and figs is an example of mutualism. This co-dependence probably had its origin some seventy million years ago, and the wasps and figs have co-evolved since then. .

Though some insects are problematic in that they are carriers of disease (for example, mosquitos and malaria, ticks and Lyme disease); it is nevertheless true that without insects food chains and ecological systems would collapse.  Insects act as  pollinators not just of garden flowers, but of crops,  natural pest control agents (ladybirds eat aphids), Decomposers, breaking down waste products of other animals, remains of dead plants and animals (dung beetles). Their activity ensures the recycling of nutrients in complex biogeochemical cycles. However, as the woodlands’ blog has reported previously, insects (like so many wildlife species) are under threat.  They are in decline due to loss and damage of habitats,  climate change,  pollution and  pesticide use. The decline in insect numbers (in the UK) is ‘monitored’ through BUGLIFE and Kent Wildlife Trust.  Each year a survey is undertaken using the ‘splatometer technique’, in which motorists are asked to record the number of flying insects (e.g. moths, flies, aphids, bees and flying beetles) that are squashed on their front number plate (after a journey).  The length of the journey is recorded, a photo taken and count details uploaded via the BUGLIFE APP, the app includes a tutorial and some safety advice.  Comparing this year’s results of over 6000 journeys with those gathered in 2004 (by the RSPB, who used the same method) reveals a dramatic fall in flying insect numbers.   London, for example, showed a dramatic fall in numbers of 91%.  The fall across England was 83%, Wales saw a 79% drop and Scotland a 76% fall.   Whilst figures for Northern Ireland were limited they suggest a 54% decline. [caption id="attachment_21589" align="alignleft" width="300"] bumblebees favour teasels[/caption] Insects [and other wildlife species] can be helped by: Creating larger areas of natural habitats (many have been lost to roads, agriculture, urban expansion) Creating wildlife corridors to join up similiar habitats/ecosystems throughout the landscape Creating wild flower ‘meadows’ by road sides, verges etc Reducing the use of pesticides and other chemicals which have significant effects on wildlife.  The effect of neonicotinoids on bees and bumblebees is well documented.       

The period since WW2 has seen urban areas and, indeed farms, expand across the UK. The number of places where wildlife can thrive has been eroded.  Gardens and lawns have been changed to provide parking for cars, lawns are mowed and ‘weed-killered’, or worst still replaced with artificial grass so there is not a weed in sight.  Fortunately there are now initiatives like No Mow May that promote the growing of wild flowers in lawns and public spaces, like roadsides and verges.  Many common weeds are simply wildflowers by another name. Wild flowers / weeds (like dandelions, ragworts, clovers) are a lifeline for bees and bumblebees - who are facing so many threats [pesticides, habitat loss, invasive species] so adequate food is important. The flowers of these wild flowers / weeds offer food for a wide range of endangered bees, and at times when other resources are limited.  Dandelions, for example, offer an abundant source of nectar and pollen for bees & bumblebees when other options are limited - especially in urban settings. They produce their flowers (and therefore nectar and pollen) from early Spring right through to the onset of Winter. Recent studies have shown that the diet of bees has changed over the years.   In the past, the bees were able to forage and collect pollen and nectar from a wide variety of plants but with the loss of ‘natural’ wild areas their diet is now often dominated by brambles, clover and dandelions.  In the case of dandelions, their simple, open flowers makes for ease of collection.  They are visited by honey bees, bumblebees and carder bees.   Some studies have indicated that dandelion pollen, whilst it is rich in the amino acid proline,  has low levels or lacks certain amino acids (such as valine and isoleucine).  Bees need the same ten essential amino acids as us.  Without a supply of these particular amino acids, the development and growth of bees is impaired, as is their disease resistance and ability to raise the brood.  So, it is important to find ways to offer our pollinators a range of plants / pollen to provide all their essential nutrients. interesting related papers Food for Pollinators: Quantifying the Nectar and Pollen Resources of Urban Flower Meadows: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0158117 Shifts in honeybee foraging reveal historical changes in floral resources: https://www.nature.com/articles/s42003-020-01562-4