Serious Insect Crisis

 When do we wake up?

Queen of Spain Fritillary/Storplettet Perlemorsommerfugl/ photo GB

Butterflies and other insects are rapidly declining everywhere in Europe - and not least in Denmark. Scientists point, among other things, to pesticides, monoculture and lack of space as reasons.
 
A new investigation published in the prestigious journal Science shows that the insects of Europe disappear -  this is even a talk about an ecological collapse. The German scientists have examined the insect occurrence in more than 100 nature reserves in western Europe - and the insects are extinct even in the nature reserves. The biomass of insects have fallen with more than 80 %.

The drastic decline for the insects of Europe could mean a decline in the number of birds, which has already been identified in Denmark, where since the 1970s four out of five partridges, three out of four lapwings and more than half the skylarks have disappeared. Huge areas - which earlier was nature- were ploughed without putting something else instead -  and at the same time we experience the climate changes.

Sad but true -many Danish politicians apparently do not care, on the contrary there is a support for that Denmark - as one of few countries of EU - fights against a ban on pesticides, ( because the Danish agriculture demands it), which could represent a risc both to ourselves and the wild bees.

It is said that the approval of spraying in Denmark is tough, but in the approval is alone considered if a substance is representing a risc for the ground water or if it is exceeding limits in our food. It is not  evaluated what happens upon the ground and it is not taken into account that herbicides like Roundup, which is the most used in Denmark,  simply removes all plant growth where it hits -  or that 2.500 tons various active substances are spread over 60 % of Denmarks area each year -  or that the agriculture is allowed to use almost 1.000 various products.

This means that organisms in the earth, the wild plants of the fields and the insects upon the plants and the birds who live by the insects are being pushed more and more in the intensive Danish farm land. This happens in a degree where we are the witness of a slow collapse of ecological balances in the whole open countryside. This also applies to nature reserves.

 


Source: Excerpt of article by Ella Maria Bisschop-Larsen, Præsident for Danmarks Naturfredningsforening, Journal "Natur og Miljø",  September 2017. 

Bumblebee/ photo:GB

An ecological study in Western Germany. 
The amount of insects collected by monitoring of traps in Orbroicher Bruch nature reserve in north west germany decreased by 78% in 24 years.


Each spring since 1989 insect traps have been set up in meadows and woodlands in Orbroicher Bruch nature reserve and 87 other nature areas in the West German state Nordrhein-Westfalen.

Recently the scientists presented alarming results: The average biomass of insects caught during summer was decreased from 1,6 kilo pr. trap in 1989 till only 300 gram pr. trap in 2014.

"The decline is dramatic and depressing and this applies to all kinds of insects, including butterflies, wild bees and hoverflies ", says Martin Sorg, who is entomologist from  Krefeld Entomological Society, which is responsible for the monitoring project.

Several other studies from the western part of the world support the results from Germany.

The insects disappear everywhere.






Grethe Bachmann
Source/ Natur og Miljø, September 2017 

Brown Hairstreak / Guldhale

Thecla betulae



The Brown Hairstreak has a wing span of 33-41 mm. It is easy to recognize by the golden colours of the underside and the marked black/white lines. From the upperside the female is recognizable by the large, orange spot on the front wing. The male can - seen from the upperside - look like the Satyrum-species, but these always keep their wings folded during rest.

The flying period is from first August til mid September and sometimes even later. The flying period starts later than any other Danish butterfly. Brown Hairstreak lives in pastures and light-open thickets and glades with a large growth of blackthorn or cherry plum. It overwinters as egg upon the branches of the fodderplant, and the caterpillar first develops inside the egg in spring. The caterpillar's fodderplant are blackthorn (Prunus spinosus), cherry plum (P. ceracifera) and sometimes plum (P. domestica), wild cherry (P. avium) or other Prunus-species.

The flight of this butterfly is fast and restless, but the species spend much time in the treetops, where they sit in the sun with half spread wings or seek food like honey dew. They also seek to thistle, yarrow, goldenrod, hemp-agrimony, heather or other flowers or to overripe fruit (i.e. fermenting blackberry still on the vines). Females, who need much energy by the oviposition, are seen more often on flowers and fruit than males.

Brown Hairstreak is in some years seen in large numbers, but as a rule it is few in number and difficult to find. It is in decline in the agricultural areas. It is very susceptible to pesticides and is never seen in sprayed areas. It has disappeared from some places on the Danish islands during the 1950s.

Source: Michael Stoltze, Dagsommerfugle i Danmark, 1997.


Black Hairstreak/Slåensommerfugl , Satyrum pruni,  - is a very rare butterfly, today seen in Midwest- England. It might be extinct in Denmark. Not seen since 1987.

White-letter Hairstreak/ Det hvide W/ Satyrum w-album, ccommon in most of Denmark but might be diminish because of the sick elm-trees.  

The Ilex Hairstreak /  Egesommerfugl / Satyrum ilicis, is  close to extinction  in Denmark, only known from one place.

The Purple Hairstreak/ Blåhale  (Neozephyrus quercus) common in Denmark

text and photo: grethe bachmann
photo of Brown Hairstreak, Sletterhage, Helgenæs August 2007: grethe bachmann

A Dark Variety of Silver-washed Fritillary in Bjerge skov south of Horsens.

Argynnis paphia: Silver-washed Fritillary/ Kejserkåbe; 
dark variety :  Argynnis paphia f. valesina

an orange male meets the valesina

In the month of  July the Silver-washed Fritillary (Argynnis paphia)  is easy to observe in Bjerge/Bjerre skov, a forest south of Horsens. On this day in mid July there were numbers of the pretty orange male flying around among the brambles. The Danish name is Emperor's Robe, and the beautiful deep orange colour with the spots and stripes would fit an emperor very well.

But suddenly came a dark variety, which we had never seen before.There was even a date between an orange male and a dark silver-washed female upon the road. 

This dark variety was named by a famous English lepidopterist Frederick William Frohawk, who named it after his daughter Valezina and called it Argynnis paphia f. valesina.  This spectacular form occurs in a small percentage of females. It is quite distinctive in flight looking like an overgrown ringlet and has the common name of the Greenish Silver-washed Fritillary.

Argynnis paphia f. valesina

Frohawk was the author of Natural History of British Butterflies (1914), The Complete Book of British Butterflies (1934) and Varieties of British Butterflies (1938).  At seven he spotted and caught a rare Pale Clouded Yellow butterfly.  In ab. 1880 Frohawk concentrated on illustration and obtained his first commission for illustrating The Field. Frohawk was encouraged in his work by Lord Walter Rotschild, who later bought his water-colours of butterflies His butterfly collections are now part of the Rothschild collection in the Natural History Museum at London.

Argynnis paphia f. valesina

Silver-washed Fritillary/Kejserkåbe

The Silver-washed fritillary /Kejserkåbe in Denmark:
The spread of the Silver-washed fritillary is somewhat dispersed in Denmark. It has disappeared from large parts of Jutland and Funen. It was earlier widespread in hardwoods in all parts of Denmark.


Problems: The silver-washed fritillary is found in forest glades - and such glades should not be either drained, fertilized or sprayed with pesticides - but hay harvesting and extensive grazing during period would be beneficial. Livestock in the forest is also beneficial,since it brings light and warmth and improved conditions for the violet, which is the host plant of the Silver-washed fritillary.

In the last time of their flight period the Silver-washed fritillary flies often to other habitats, sometimes to residential areas.

The Silver-washed fritillary (Argynnis paphia)  is on the Danish red list, but it is neither protected or listed in Denmark.

Source: Fugle og Natur, Michael Stoltze; British wikipedia, 
photo: Bjerge/Bjerre skov July 2014: grethe bachmann     

Nature in Trouble

Lapwing, Vilsted Sø


Skylark, Ertebølle

Many years ago, in 1986, a plan for pesticides was introduced in DK. The purpose was to lower the use of pesticides in order to keep the diversity of nature. Unfortunately it has developed in the wrong direction. I.e. has the population of lapwing, skylark, partridge and hare minimized severely, caused by the barren landscape. The waterworks state that more and more drillings contain rests of pesticides. The agriculture says that the use of pesticides is necessary caused by "hunger in the world", while *DN 's representative says "rubbish", cause 85% of the Danish corn-production is used for animal-fodder.

* Dansk Naturfredning


Partridge, Rugård

Hare, Oudrup Hede

Source: Natur og Miljø, Danmarks Naturfredningsforening, nr. 4, Nov. 2009.

photos ⓒ 2007-2009: grethe bachmann