The woodlands blog has previously reported on the worrying decline in insect numbers, but there has been yet another report detailing significant falls in the populations of (flying) insects.  This survey was run by Buglife and the Kent Wildlife Trust  (KWT) using a smart phone app - “Bugs Matter”. The survey suggest that between 2004 and 2021 the number of flying insects (in Kent) has fallen by some 70%.  This finding is not dissimilar to that carried out in rural Denmark which found an 80% decline in insect numbers between 1997 and 2017. Insects are vital to the functioning of ecosystems.  They help maintain: A healthy environment Contribute to the recycling of organic matter Act as pollinating agents Help control pests Without insects the ‘web of life’ begins to fall apart.  The loss of insects and other forms of wildlife can be helped by: Creating larger areas of natural habitats (many have been lost to roads, agriculture, urban expansion) Creating wildlife corridors to link 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 Buglife survey makes use of a simple technique to estimate insect abundance - the ‘splatometer’.  This involves counting the number of ‘squashed’ insects on car registration plates.  The Danish survey used a similar method but looked at insects found on car windscreens.   This summer Buglife is hoping that people will again contribute to another survey using the splatometer technique.  The survey will run from June 1st to August 31st.   To contribute to the survey you will need :- The “Bugs matter” app (free) and a smart phone. To create an account to send in your results Clean the car number plate before the start of any journey in your vehicle At the end of your journey, count the number of squashed insects on the number plate (using the splatometer grid - which will be sent to you) and take a photo. This enables Buglife to calculate the ‘splat rate’, that is the number of insects recorded per mile.  NB.  Journeys on wet days are not recorded as rain might wash off any insects from the number plate.   The more journeys and counts that you can carry out the better, and zero counts of squashed insects are just as important as those with an actual number of squashed insects. Note : The app includes a tutorial and some safety advice. It is available for android or apple phones.

We know that insects (especially, bumblebees, bees, hover flies) are the world’s top pollinators, and we also know from many reports that many insect species are in decline.  Crops such as tomatoes, blueberries, peppers, cocoa, coffee, almonds and cherries are dependent on these pollinators.  Climate change, increasing temperatures and extreme weather events are affecting plants and animals across the world, and it seems that social insects, like bumblebees, are particularly impacted. Research with bumblebee colonies (at Stockholm University) has indicated that if the colonies are exposed to higher temperatures (than normal) then the workers in the colonies were smaller.  This decrease in body size could affect their foraging behaviour and the collection of pollen,  which would mean less food brought back to the colony and reduced pollination of plants. Studies in the United States looked at some 20,000 bees  (bumblebees, leafcutter bees, mason bees etc) along the Rocky Mountains, a region which is vulnerable to climate change.  It was found that the larger bees (particularly bumblebees) and those that built nests with combs were affected most by increases in temperature.  On the plus side, smaller (soil nesting) bees fared better.  Bumblebees would seem to have a lower heat tolerance.  The loss of bigger bees, which generally can fly and forage further may again mean reduction in long distance pollination (which promotes outbreeding in plant populations). One reason why hot or hotter weather affects bumblebees is that it influences the nectar that the bumblebees collect.  The balance of the various micro-organisms (bacteria and yeasts) in the nectar changes.  Whilst bumblebees are attracted to nectar with some microbes in it, a small change in temperature can speed up the metabolism / growth of the microbes so that they use up more of the sugar - with the result that it is less palatable / less nutritious for the bees.  Experiments conducted at the University of California have shown that bees did not ‘like’ the nectar rich in microbes, nor a sterile one - with no microbes at all. There seems to be a 'happy medium' in terms of the composition of the nectar. There seems to be a growing consensus that climate change, increasing temperatures and extreme events are pushing bumblebees (in particular) beyond their physiological limits. [caption id="attachment_38081" align="aligncenter" width="650"] Bumblebee visiting foxglove[/caption]

Butterfly Conservation has organised the Big Butterfly Count for the last twelve years.  This year, the count took place between 16th July and August 8th.  The count gives some information of how butterfly and moth populations are faring.  Both butterfly and moth numbers give us some information about the ‘health’ of our environment, and indeed what has been termed the insect apocalypse. Though some 150,000 counts were registered this year, the ‘average’ number of butterflies / moths recorded per count was nine. This was down from the average count of 11 last year,  and 16 in 2019.   The total number of butterflies / moths counted was down by some 14% overall compared to last year. Those species that had significantly reduced counts were Peacock down by 64% Common Blue down by 59% Speckled wood was down by 41% Small tortoiseshell and the Comma dropped by 32% On a more positive note, the ringlet and marbled white were recorded in greater numbers (but they did have low counts last year). The Spring weather was probably a significant factor in these generally disappointing results.  The wet May would not have helped breeding or feeding; low temperatures are not conducive to activity.  The poor weather would particularly impact on those species that normally produce two broads a year.   Further information on the results of the count can be found the Butterfly Conservation website :  here.

Silwood Park is part of Imperial College, a postgraduate campus, located some 25 miles west of central London, near Ascot. It is a centre for research and teaching in ecology and allied disciplines. The campus includes areas of wet woodlands, acid grasslands, traditional orchards and parkland. The veteran and ancient trees support an significant number of rare species of insects, lichens and fungi that depend on decaying wood. Silwood is the heart of the wildlife corridors for the surrounding area.  Read more...

The appearance of bumblebees is one of the hallmarks of Spring, and their buzzing can be heard in gardens throughout the summer months.  They are important pollinators in our gardens, but also for some crop species that use buzz pollination (like tomatoes). Like other bees, indeed insects in general,  bumblebees face a number of threats - one of which is a fungal parasite (Nosema bombi). This fungus reduces the lifespan of worker bees in the bumblebee colonies and also the production of new queens; it has been associated with the decline in population numbers of North American bumblebees. Read more...

The woodlands blog has reported on the anthropocene - how human activity is creating a geological era characterised by human impact on the Earth.  Now a report finds that human-made (artificial) material will this year surpass the sum total of all living material (biomass) on earth. https://www.nature.com/articles/s41586-020-3010-5 A Swedish study has shown that crop yield can be enhanced  by ensuring that woodland and grassland areas are present in the vicinity of crop fields.    If the landscape is more diverse in terms of plants and habitats, then the number of pollinators (bees snd bumblebees) is greater.   Read more...

Plants and animals provide us with many important ecosystem services.   One critical ecosystem service is pollination; this is mainly done by insects - such as bees, bumblebees, moths and hoverflies. Insects are often attracted to flowers by scent, when volatile oils are released that act as chemical signals to ‘tell’ insects about their presence in the environment. This signalling is the result of a relationship between flowers and insects that has evolved over millions of years.  However, in relatively recent times, we (as a species) have been responsible for many changes to the Earth and its atmosphere.  Many gases and materials have been released into the air which have ‘mixed’ with the wide variety of natural scents and smells that are used for plant and animal communication. One such pollutant at low levels is ozone. Higher up in the atmosphere, the ozone layer prevents too much damaging UV light from reaching the Earth's surface.  However, at ground level, the oxidizing potential of ozone can cause damage to respiratory tissues in animals. Read more...

It is clear that wildlife is in decline, not just in the U.K, but across Europe, America - in fact wherever you look. Over the last century, over 90% of meadows have been lost in the U.K.   This decline in natural habitats / ecosystems is largely due to urban growth and the expansion & intensification of agriculture.  Concomitant with the loss of natural habitats is the loss of wildlife.  One particular cause for concern is the ‘disappearance’ or decline in numbers of some many insect species, especially pollinators.  The woodlands blog has reported many times on honeybee and bumblebee numbers.`   Pollinators, such as bees, butterflies or hoverflies,  need to find food (nectar & pollen), plants on which their larvae can feed, sites for nesting, reproduction and over-wintering. With the growth of cities and agriculture there has been an expansion of transport networks, particularly roads. There are more than 30,000 miles of major roads in UK in 2019, with some 2,300+ miles of that being motorways.   Roads clearly have a number of ecological impacts (dividing up the landscape being one) but they also offer ‘habitats’ alongside the road. Read more...