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Archive for the ‘Arhgropoda’ Category

About 30-40% of the visitors to the Manchester Museum’s Entomology Department are art or design students and professionals, who come over to get inspired by the variety of insect shapes, colours and patterns, and to talk to the museum curatorial staff about what interests them. Museum’s curators are especially pleased when such visits result in something tangible, such as an installations, original ideas for contemporary product and/or jewellery design, and, of course, pure examples of fine art.

Here we are pleased to present an interview with Robin Gregson-Brown, a Lepidoptera artist as he calls himself, from Derbyshire (recorded 20th October 2016). At the age of 80 and in retirement, Robin has embarked a new career of poetic artist of nature. And what could be more beautiful nature’s beautiful creatures than moths and butterflies? Hardly anything! Robin is fascinated by Lepidoptera all his life and now started to satisfy his passion by painting them in mixed media.

In collaboration with the Derby Museum and the Manchester University Museum, he has produced a series of spellbinding images of endangered and extinct butterflies, which were displayed once in his personal exhibition at the Derby Museum (22nd May – 5th June 2016).

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Do butterflies migrate and if they do how long distances are they able to cover? How many British Lepidoptera species do migrate to the country? Why do butterflies and moths migrate? These and other questions related to migratory species of Lepidoptera (butterflies and moths) were discussed with an expert, Prof Laurence Cook of the University of Manchester (Manchester, UK).

The interview is presented here in two parts.

Watch interview, part one:

Watch interview, part two:

You can find useful information about two British migrant species (Painted lady and Humming-bird Hawk-moth) and the initiative ‘Migrant Watch’ online on the Butterfly Conservation site, here.

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In recent years, an increasing concern has been caused by the decline of butterflies in Britain. Almost half of the 59 resident species have reduced their ranges over the last 150 years, and five species have become extinct: Black-veined White (Aporia crataegi; c. 1925); Large Copper (Lycaena dispar, c. 1851); Mazarine Blue (Cyaniris semiargus, c. 1903); Large Blue (Maculinea arion, c. 1979); and Large Tortoiseshell (Nymphalis polychloros, 1980s?). Many of the remaining butterfly species continue to decline nationally or even have become extinct locally on many sites. One of such species is the Silver-studded Blue (Plebejus argus), which is scarce elsewhere in the UK with a high extinction rate (evaluated as 25%): i.e., the species no longer occurs in about a quarter of the localities from where it was recorded in the 1970s. In the UK, this species declined most severely from 1950 to 1980, but with relatively few extinctions occurring between 1980 and 1985 (data by Warren, 1993, for Central Southern Britain).

The main reason for extinction/declining of this and other butterfly species in the UK is a combination of habitat loss and fragmentation/isolation, and changes in habitat management (especially, in Forestry Commission and Public Authority sites). Butterflies are known to be highly sensitive to environmental changes and therefore they often decline whilst their larval food-plants are still widespread and abundant. However, any changes in butterfly populations are to be seen as early indicators of habitat changes that in the future will affect many other wildlife groups.

The Silver-studded Blue is more usually associated with heathland habitats, and a number of regional nature reserves have been specifically established to protect it. One of such sites is the Prees Heath Common Reserve (Shropshire), the last sanctuary for the Silver-studded Blue (Plebejus argus) in the Midlands.

Stephen Lewis, Officer at the Prees Heath Reserve, visited the Manchester Museum on 19/12/2014 in order to study historical records of the Silver-studded Blue from the Midlands on the basis of museum specimens.  He also gave us a short interview about the conservation of the Silver-studded Blue in Shropshire (see below).

A more complete story of the Silver-studded Blue butterfly at the Prees Heath Common Reserve presented by Stephen Lewis can be seen in the following short video.

If you are interested in British Butterfly Conservation (the British Butterfly Conservation Society) and their currently formulated strategy for British butterflies please visit the society’s site.

Further reading:

Warren, M.S. 1993. A review of butterfly conservation in Central Southern Britain: I. Protection, evaluation and extinction on prime sites. – Biological Conservation, 64, 25-35; pdf-file online.

Warren M.S., Barnett L.K., Gibbons D.W. & Avery M.I. 1997. Assessing national conservation priorities: an improved red list of British butterflies. – Biological Conservation, 82: 317-328; pdf-file online.

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The Golden Orb-Weaving spider – Nephila clavipes (Linnaeus, 1767) of the family Nephilidae – is known from USA to Argentina. In Costa Rica, it occurs in lowland and premontane tropical rain forests. Females make large aerial webs in which they usually occupy the centre. Orb-web spiders are effective predators and can easily subdue prey that is significantly larger and heavier than the spider (see on photo).

Two females of Nephila clavipes with prey; Costa Rica.

Two females of Nephila clavipes with prey; Costa Rica.

One of the most peculiar characteristic of this species, as well as of other Nephila species, is an extreme sexual size dimorphism, where dwarf males can be many times smaller and lighter than the females (see on photo). Numerous hypotheses have been proposed to explain the factors that may give rise to such size dimorphism in spiders. Some of them are briefly discussed here.

In the case of Nephila, it is argued that that large size in females could be driven by selection on female fecundity (= the potential reproductive capacity), acting to increase the number of offspring produced. With the high level of juvenile mortality, the production of larger numbers of offspring is crucial for survival of the species. Thus such size dimorphism is almost always due to female gigantism rather than male dwarfism.

As was demonstrated for some African species [e.g., Nephila pilipes (Fabricius 1793)], females continue to grow after reaching maturity. The females mature at varying body sizes and instars and then continue to grow by molting the entire exoskeleton except their copulatory organs (=genitalia). Apparently, this is why in Costa Rica Nephila clavipes is represented by mature females of markedly variable body sizes (although, to date, a post-maturity molting has not been described for this species).

In a short video presented below (courtesy of Alex Villegas, Costa Rica) it is shown how a dwarf male of Nephila clavipes is approaching a giant female in its attempts to mate, alas unsuccessfully this tiem. Indeed, the male is to be careful in order not to be mixed up by the female with a potential prey.

Further reading:

Kuntner, M. & Coddington J.A. 2009. Discovery of the largest orbweaving spider species: the evolution of gigantism in Nephila. – Plos; DOI: 10.1371/journal.pone.0007516

Kuntner M., S. Zhang, M. Gregorič, and D. Li. 2012. Nephila female gigantism attained through post-maturity molting. – Journal of Arachnology 40(3):345-347. DOI: http://dx.doi.org/10.1636/B12-03.1

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It is known that during the latest Pleistocene glaciations (2.59-0.01 Million years ago) the territory of Britain, as well as of Ireland and many other territories of the northern hemisphere, were covered by glacier and were uninhabitable for terrestrial fauna. During glaciations animals and birds either migrated southward or died out. Palaeontological and genetic evidence indicates that the majority of the contemporary fauna of Britain arrived from continental Europe dispersing across a land bridge that existed between Britain and mainland Europe during the short period after ice retreat and before it was submerged by rising sea level (ca. 0.45 Mya).

However, surprisingly, there are few British species that were able to survive the latest Ice Ages, for instance, the endemic Groundwater Shrimp (Niphargus glenniei; see on the photos below) currently known from cave ecosystems of Devon and Cornwall only. Another endemic species of the groundwater shrimps, restricted to Ireland, is Niphargus irlandicus. None of these species is known outside southern England and Ireland correspondingly.

Niphargus glenniei, the Groundwater shrimp that is adapted to live in subterranean environments. Shrimps are blind, lack pigmentation and have elongated appendages. Photo credit: Chris Proctor.

Niphargus glenniei, the Groundwater shrimp that is adapted to live in subterranean environments. Shrimps are blind, lack pigmentation and have elongated appendages. Photo credit: Chris Proctor.

As argued by McNerney et al. (2014), the most recent common ancestor of both species and all other Niphargus species (over 300 species distributed in cave ecosystems across Europe) was isolated approximately 87 Million years ago, i.e. during the late Cretaceous period (100–66 Mya). More importantly, that the two endemics (glenniei and irlandicus) should have been where they are now for at least 19.5 Mya and thus they have survived the entire Pleitocene period and many glaciations in the groundwater. This makes both groundwater shrimps the oldest known species of the British fauna.

This story is based on the paper by McNerney et al. (2014), The ancient Britons: groundwater fauna survived extreme climate change over tens of millions of years across NW Europe. Molecular Ecology, 23: 1153-1166; doi: 10.1111/mec.12664

 

 

 

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During the field trip to Iceland, we have visited many places of interests, including of course pebble-beaches on sea shores made of  grey, smooth basalt pebbles.

Grey basalt pebbles on the sea-shore of western Iceland (Londrangar, Snaefellsnes)

Grey basalt pebbles on the sea-shore of western Iceland (Londrangar, Snaefellsnes)

To my surprise, the same pebbles can be found on shelves of many gift- or craft-shops that are available virtually in every hamlet, village or town of Iceland. However, the pebbles in shops are nicely hand-painted, representing examples of mini-artworks, often naive but always touchy (see on the photos below). In one shop the painted pebbles were crafted as ladybirds of various shapes and colours (from yellow and green to the traditional red-coloured beetles).

Lovely ladybird crafted from pebble, NW Iceland.

Lovely ladybird crafted from pebble, NW Iceland.

I don’t know whether it is indeed a national Icelandic tradition to hand-paint pebbles, such craft is suitable to everyone, from children to enthusiastic adults, allowing everyone to become a master of own mini-masterpiece. Someone called this the ‘beach stone craft’; further instruction and inspiration of this craft can be found here.

 

 

 

 

 

 

Han-painted pebbles with diverse wishes, craft festival at Hrafnagil near Akureyri, NW Iceland.

Hand-painted pebbles with diverse wishes, craft festival at Hrafnagil near Akureyri, NW Iceland.

A collection of artworks (=painted pebbles) produced by students of a local primary school on the occasion of the 50th anniversary of the Natural History Museum in Heimaey Island.

A collection of artworks (=painted pebbles) produced by students of a local primary school on the occasion of the 50th anniversary of the Natural History Museum in Heimaey Island.

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On the second day of our field trip to Iceland, we visited the interesting site lying in the southern municipality of Reykjavik, called Garðabær, which literally means ‘Garden Town’. We walked around the beautiful Lake Urridavatn surrounded by boggy meadows full of sedge, dwarf bushes (like blue berry) and cotton grass (see on the photo).

Boggy meadow with cotton grass (left) and the blue berry bush (right) near Lake Urridavatn in Iceland

Boggy meadow with cotton grass (left) and the blue berry bush (right) near Lake Urridavatn in Iceland

On the meadow side of the path to the lake we found a plastic cup thrown by someone a few days ago. Incidentally, the cup, which was partly filled with rain water, became a deadly trap to insects and spiders. Having inspected the content of the cup I found two specimens of crab spiders (Xysticus sp.; male and female), one specimen of the ground beetle (family Carabidae) and one harvestman (family Phalangiidae). So, the cup ‘worked’ exactly in the way as true pitfall traps (see also here) that are used by scientists for ecological surveys. A poor thinking or maybe carelessness of someone who threw this plastic cup away instead of dropping it into a waste bin resulted in some casualties of minibeasts. Throwing a plastic cup (or any unwanted plastic item) away is hardly seen as a great deal or an action causing any threat to wild life. However, my short and simple story seems to say otherwise. In simple words, it reminds us that recycling waste is essential to both natural environment and humans, minimizing an unnecessary risk of damage to the environment and helping out our planet be a better place to live in. More about recycling can be seen here and here.

The plastic cup that became a deadly trap to a number of minibeasts near Lake Urridavatn in Iceland. See also a short video below.

The plastic cup that became a deadly trap to a number of minibeasts near Lake Urridavatn in Iceland. See also a short video below.

 

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