The Guardian, and Daily Mail report last year was the third good summer in a row for butterflies and the 10th best since records began, but one-third of Britain’s species are still in long-term decline.
Conservation scientists warned against overstating the butterfly boom, saying perceptions of a “good” year have lowered in the light of plummeting insect numbers. “Perhaps because of the sunny spring weather last year and the fact that more people were enjoying nature as part of their day-to-day activities, butterflies seemed more numerous,” said Richard Fox, of Butterfly Conservation.
Species that have been introduced into areas outside their
natural range through human actions and that pose a threat to native wildlife,
are known as invasive non-native species. Sadly some
have made their way to Normandy, affecting our native wildlife. However, you can help, by recognising them
and reporting them, and even taking measures to control them. Read these
details, from FNW Committee member, Bill Stanworth, on three such species to
look out for.
The box-tree moth (Cydalima perspectalis) has been recorded for the first time in Normandy at Springhill garden. Adult moths were attracted to a mercury vapour lamp in July 2020 and later in the year larvae were found on its foodplant, box (Buxus sempervirens) growing in the same garden. The moth is a native of the Far East and so its arrival in Europe (in 2006) is thought to have been from imported box plants – ugh.
The first record of the moth in the U.K. was from Kent in 2007 but
a year later it was found in Weybridge, Surrey. Since then the moth has been
gradually increasing and from distribution maps the moth may have been in our
area for a year or so. Papers about the moth and its distribution can be found
on the RHS website.
The adult moth, shown below is large and very distinctive. Its
markings are variable and even a brown form exists. The stripy green caterpillar
is also quite distinctive and is shown resting below on its foodplant. It creates silk strands that tie leaves together forming a lair from which it can feed and retreat into, in times
of danger.
Box-tree mothBox-tree moth catepillar
You can see from the photos below that even in less
than one season they can seriously damage the plant. Feeding signs and frass
are shown on the left and serious defoliation on the right. If you see this
happening to your box bushes please check with the RHS and other websites for
control methods (preferably using the non-pesticide methods).
We urge you to control this species as box is a
native plant in southern England and it could have a serious effect on our
best-known native boxwood at Box Hill, Surrey and other sites in the county and
country. If you see the box-tree moth the RHS would like to know, you
can submit your records on their website via their box-tree moth survey.
Box bush damageBox bush damage
The second pest to look out for is the Agapanthus gall midge, which was also found in Springhill garden for the first time in 2020. It’s another devastating pest (if you grow Agapanthus in your garden!), a fly this time, that lays its eggs on the young Agapanthus flower buds. The tiny, creamy-yellow larvae develop and cause the flower bud to become distorted, go brownish and most fail to open. A photograph of the affected buds (here detached from the plants) is shown below.
According to the RHS the midge causing this was
new to science and only discovered in 2014, this time at Wisley but it is probably
a native of southern Africa, home of the plants. Control methods are given on
the RHS website. Agapanthus flowers are popular with some native pollinators; an
example shown here is probably a melanistic garden bumblebee (Bombus hortorum) from Springhill garden.
This one spent a lot of time on this white flowered variety! Sadly many Agapanthus flowers at Springhill were
ruined this year.
The RHS are asking for help from gardeners who
have seen agapanthus gall midge or damaged flowers and request you send photos
of symptoms on the flowers and buds, plus opened buds showing larvae where
possible, to entomology@rhs.org.uk on their website.
Agapanthus flower budsBumble bee on Agapanthus flower
Another invader and potential pest is the gypsy moth (Lymantria dispar). The male shown below was attracted to a mercury vapour lamp at Springhill garden on 7 August 2020. On mainland Europe the moth can be a serious pest, stripping broadleaved trees (particularly apple, plum and willows; oaks and poplars in forests) and bushes.
Look out for patches
of eggs covered with yellow/brown hairs on trunks and walls over winter or for
large dark grey/black hairy caterpillers with reddish spots from April to June/July.
Apparently the hairs don’t cause irritation of the skin unlike the oak
processionary moth. The RHS website says ‘whilst a single
defoliation from this caterpillar even early in the season, should not affect
the vigour of a host plant, repeated defoliations can have an adverse effect’
and advice is given with regards control. They also very sensibly say ‘where
possible tolerate populations of caterpillars’.
This moth (not mentioned/recorded in ‘The Larger Moths of Surrey’ [Graham A. Collins] published
by SWT in 1997) was a former resident in the East Anglian fens but
it lived on bog-myrtle and creeping willow and so wasn’t considered a pest. The
European strain was accidentally introduced and
has spread rapidly in the London area. Hopefully, as the large bodied females
are mostly flightless, we won’t be troubled for a while.
There is no
statutory requirement to notify sightings of gypsy moth to the plant health
authorities but you can report serious damage to the government’s ‘Forest Research’
website: TreeAlert (their on-line
pest reporting tool).
Gypsy moth
2018 saw the first arrival of the oak processionary moth (Thaumetopoea processionea) to Normandy (see our previous article). No moths were seen in Normandy in 2019 as far as we know but you may have seen that the Forestry Commission have erected posters warning the public to be alert for them and report them when seen. In addition at least one team has been seen on Normandy Common searching for evidence of their presence. This year three males were attracted to the mercury vapour lamp at Springhill so please stay vigilant.
The Guardian and iNEWS report moths in Britain have declined in abundance by a third over the past 50 years, according to a study. The declines of 39% in the abundance (relative representation in an ecosystem) of larger moth species over southern Britain and a 22% fall across northern Britain add to the picture of calamitous declines in flying insects in the industrialised world.
Among the most rapidly declining of Britain’s 900 larger moth species are the stout dart (-81% over an average 10-year period), the golden plusia (-58%) and the garden dart (-54%).
The Guardian, and iNEWS report it is brown, stinky and will strike fear into the hearts of apple and other fruit growers. Scientists have now confirmed that the brown marmorated stink bug (Halyomorpha halys), a small flying insect that emits an unpleasant almond-like odour, has arrived in Britain, after most probably hitching a ride on packaging crates.
Bog Bush-Cricket (Metrioptera brachyptera) female – Creech Heath, Dorset Photo by Will Atkins under creative commons
iNews reports traffic noise makes female crickets less picky when choosing a mate, a new study from Anglia Ruskin University suggests, threatening their long-term survival. Male crickets perform courtship songs to attract a female by rubbing their wings together. Females will generally pick the male with the best serenade. But road noise is making it harder for female crickets to distinguish between a top notch song and an off-key performance, the researchers said.
The Independent reports neonicotinoids, linked to collapse in insect pollinator populations, knock bees’ and flies’ behavioural rhythms out of sync. Almost all living creatures require sleep in some form to function properly, and insects are no exception. But new research warns exposure to a common insecticide, banned in the EU but set for reintroduction to the UK, impacts the sleep of bumblebees and fruit flies, and “may help us understand why insect pollinators are vanishing from the wild”.
The Guardian reports one of Britain’s largest spiders has been discovered on a Ministry of Defence training ground in Surrey having not been seen in the country for 27 years.
Mike Waite from Surrey Wildlife Trust discovered the elusive spider after two years of trawling around after dark looking for it on the Surrey military site, which the MoD is not naming for security reasons.
The great fox-spider is a night-time hunter, known for its speed and agility, as well as its eight black eyes which give it wraparound vision. The critically endangered spider was assumed extinct in Britain after last being spotted in 1993 on Hankley Common in Surrey.
INEWS reports one of England’s rarest insects, the endangered Rock-rose Pot Beetle, has made a remarkable recovery with more being spotted this year than in the last 150 years combined.
The Telegraph reports if not kept under control, the box-tree moth could disrupt natural ecological balances irrevocably. It now infests most of Europe except a few Nordic regions and high mountainous areas. With climate change it may spread further.
Photos of box tree moth caterpillar by Frank Van Hevel and box tree moth by David Shrt, both under creative commons.
The Guardianreports if you see a violet carpenter bee, xylocopa violacea, in Britain, it seems too exotic for our shores, and too big. It is up to 3cm long, the size of our largest bumble bee, and it looks even larger when flying with an impressive buzz.
In late August, the adults emerge from a dead tree trunk or other old wood where they have spent the larval stage. After mating in late April or May, female bees bore holes in rotten wood and lay eggs in separate chambers, each one sealed in with a store of pollen so the emerging larvae can have a good start in life.
Climate change has brought this southern European species to our shores.
Violet carpenter bee photo by Charlie Jackson under creative commons.
In late August, the adults emerge from a dead tree trunk or other old wood where they have spent the larval stage. After mating in late April or May, female bees bore holes in rotten wood and lay eggs in separate chambers, each one sealed in with a store of pollen so the emerging larvae can have a good start in life.