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Butterfly updates

Butterfly updates

by The blog at woodlands.co.uk, 25 March, 2024, 2 comments

Solar farms have sprung up across the country with hundreds or thousands of solar panels, linked together in fields.  Now, researchers in the States have shown that sowing grasses and wild flowers in-between the panels on solar farms resulted in: A significant increase in the number of beneficial insects (bees in particular benefitted) An increase in insect diversity beneficial 'spillover effects' on adjacent farmland. The solar farms under study were sown with specially designed seed mixes. See also the previous woodlands  blog on solar panels and wildlife The seeding of solar farms would seem to offer support to : Renewable Energy Generation: Biodiversity Pollination services Habitat restoration: in fields that may have been damaged by intensive agriculture and / or development. They can also act as a refuge for native plants and wildlife. Erosion control: the root systems of native plant species (which penetrate to different depths) help prevent soil erosion. Reduced maintenance costs: as less mowing / weed control needed. The cabbage white butterfly is generally regarded as the enemy by the keen vegetable gardener.  If you are growing brassicas - cabbages, cauliflowers, brussels sprouts, broccoli, kale or pak choi, it is likely that you will have these butterflies as summer visitors.  The butterfly is white with black spots on the wings.  Males have a single spot on each of the forewings, whereas the females have paired spots. The butterflies are attracted to the plants as they produce the chemical - glucobrassicin. The butterflies can sense the glucobrassicin through the hairs on their front legs (they have three pairs of legs, a pair on each segment of the thorax). This chemical, glucobrassin, stimulates them to lay their eggs on the leaves of cabbage and other brassicas.  A female can lay up to 800 yellow eggs. These eggs may hatch and the green / black caterpillars emerge.  These caterpillars can double their mass in a day through their voracious feeding.  The adults are attracted to the glucobrassicin in the brassicas just as the caterpillars ‘enjoy’ the chemical - SINIGRIN.   When leaf tissue is damaged, the sinigrin is broken down into a mustard oil, responsible for the pungent taste of Cruciferous vegetables. There are a number of strategies that may help keep the butterfliess away from your crops, and reduce the damage by the caterpillars. Cover the plants with an insect proof mesh Offer ‘sacrificial brassicas’ away from the main crop Use companion / mixed planting, so that beneficial insects have 'hiding places' and it is more difficult for the female cabbage whites to find the brassicas.  Also, by mixing up the planting with herbs and other veg, it makes it a bit more difficult for the caterpillars to move from cabbage to cabbage etc. If you do need to use an insecticide, consider using the products derived from Bacillus thuringiensis.
woodland web updates 18

woodland web updates 18

by The blog at woodlands.co.uk, 1 July, 2022, 0 comments

Mites and bees. Varroa destructor also known as the Varroa mite is a small, external parasite of the honey bee : Apis mellifera. It is a mite. Mites are small members of the arachnids (8 legged arthropods).  The mite(s) attaches to the body of the bee and feeds upon its fat bodies; this weakens the bee. The mite also feeds on bee larvae. Not only that but the mite can act as a vector (‘distributor’) for five different viruses that also weaken the bees.  The varroa mite originally was to be found in Asia, and was parasitic on the Asian honeybee, Apis cerana.  Sadly, it has now spread to many countries and is responsible for significant infestations of European honeybee hives.  Over time, the mites have become increasingly resistant to chemical treatments. Now a program / study by the Universities of Exeter and Louisiana has been selectively breeding bees that identify and remove mites from their colonies [ie. showing hygienic behaviours].  They do this by removing infected larvae from the colony.  This is sometimes referred to as varroa sensitive hygiene.  Such colonies showed significant reduction in mite numbers and were more than twice as likely to survive winter as compared the ‘standard’ honey bees. The colonies also had reduced levels of three honey bee viruses The study looked at bee colonies across three American states, including California.  In the States, beekeepers move thousands of bee colonies to provide pollination services for many different fruit crops (e.g. almonds) in the Spring, thus winter survival of the colonies is vital. Historic rainfall records. was launched in March 2020 (during the 'first stay at home' / lockdown).  Members of the public were asked to help record digitally the information on pre-1960 weather sheets.  The Met Office archives had some 65000 sheets that contained the ‘scribbled records’ of thousands of weather stations/ weather recorders across the country.    Many of these sheets were the records of amateurs dating back decades, many before the foundation of the Met Office in 1854. One such 'recorder' was Lady Bayning of Norfolk, she was an early rainfall observer who took readings from 1835 to 1887.  Deciphering the idiosyncratic handwriting could not be done by character recognition software. However, the volunteers rose to the challenge and the task was completed in some 16 days. As a result, now the Met office has: Rainfall readings stretching back to 1836 Data from an increased number of rain guages  Identified the driest year on record - 1855 Identified the driest month on record February 1932 Identified the wettest month on record October 1903 Note : [The Met Office was founded by Robert Fitzroy, the captain of HMS Beagle, that carried Charles Darwin on his epic voyage around the globe. Fitzroy essentially established the science of weather forecasting] Trees on the move ? We know that trees can ‘move’.   They did so at the end of the last Ice Age (some 12,000 years ago).  As the glaciers retreated so trees started to return to the newly exposed soils as the temperature warmed.  The discovery of the remains of acorns in archaeological digs, and analyses of fossil pollen records indicates that even oaks colonised areas of the UK at the rate of nearly a kilometre a year.   Similarly, Norwegian Spruce colonised areas around the Baltic Sea and the boreal forests grew and expanded - long before humans arrived there.   Now we have warming temperatures as we have moved into the Anthropocene.  In order to survive changes conditions, plants, like us, have to move. So, like after the ice Age, plants and trees are on the move.  Scientists in California have calculated that as a result of global temperature changes, plants need to move northwards (or upwards) at the rate of 400+ metres a year.  In the eastern parts of the United States, it has been estimated that trees were shifted north and westward at a rate of 10 / 15 km per decade.  The conifers going north. Whilst oaks and birches going west.  In Scandinavia, which has experienced significant aspects of global warming, birch saplings are now found higher up mountains, gaining 500 metres in elevation within two decades.  Pines, spruces and willows are also growing at higher altitudes than previously.  Similar colonisations of  hillsides and ‘bare valleys” are seen in Alaska of alder, willow and dwarf birch. Further information here [caption id="attachment_38737" align="aligncenter" width="700"] Busy bee[/caption]