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Posts Tagged ‘entomology’

Copris_lunaris

Nesting by the Horned Dung Beetle (Copris lunaris): 1 – Initial stage, male (left) and female (right) working the ‘dung cake’; 2 – Female alone, making brood-balls of the ‘cake’ for laying eggs. Illustration by V.A. Timokhanov (Almaty, Kazakhstan).

Waste disposal is a growing problem for any industrialized nation. The UK alone generates about 100 million tonnes of waste each year, the majority of which is still being disposed of through landfill. The present story is about dung beetles or scarabs (family Scarabaeidae) that are involved in processing and decomposing dung.

On average, about 40% of the food intake of mammals is either excreted as urine or passed out of the body as faeces. This waste is decomposed and returned to the soil by insects that use dung as food for themselves and for their larvae, thereby preventing it from building up. How this is accomplished is best known for cattle dung.

A cow’s fresh dung pat is colonized by a succession of dung-breeding insects, numbering several dozen species and often exceeding 1000 individual insects. A total of 275 species has been reported to occur in cattle dung in Britain. The majority of them are dung beetles that feed directly on dung. There are three main ecological groups of dung beetles. First, small-sized beetles (Aphodius species) usually feed in the main dung mass. Others, like the horned dung beetle, dig burrows beneath the pat and pack pieces of dung into them for feeding their larvae (see figure above). The third group includes beetles that make spherical dung balls, roll them away and bury them intact in shallow burrows. The Sacred Scarab is the most famous of the rollers. As well as dung beetles, the pat is colonized by dung-feeding fly maggots, predatory beetles which feed on eggs and larvae of other insects, small parasitic wasps, fungus-eating insects and mites, etc. At the advanced stage of degradation, soil invertebrates, including earthworms, begin to move into the dung pat. The natural rate of dung degradation depends on temperature, humidity, habitat and season of deposition. In Britain, the complete natural disappearance of a dung pat is achieved in two to three months.

Sacred_Scarab_Stockholm

Sculpture of the Sacred Scarab in the Natural History Museum in Stokholm, Sweden. © Dmitri Logunov, Manchester Museum.

It is known that each cow produces an average of 12 dung pats per day, or over 9000 kg of solid waste per year. It is estimated that each year approximately 200 million tonnes of waste are produced by livestock in England and Wales, and about 900 million tonnes in the USA. About third of this is recycled by dung beetles. In the USA alone, the annual economic value of this service is at least $380 million.

Unfortunately, the activity of dung beetles is severely disrupted by current agricultural practices, such as the treatment of livestock with persistent anti-helminth drugs given to kill parasitic worms or helminths. Residues of these drugs can persist in the dung and are lethal to the beetles. As a result, the dung pats of animals treated with anti-helminthes remain biologically undegraded for months, fouling available grazing area. If left unprocessed, livestock wastes may present a health risk to humans, because they can contain some pathogenic microorganisms.

By recycling the nutrients locked up in dead organic materials such as dung, insects make these nutrients available to new life. As recyclers, they do an indispensable job for our planet. Without organisms breaking down dead organic materials and recycling nutrients in the wild, as well as in gardens and on farms, the planet would soon be piled deep with the waste products of its inhabitants, and potential spread of diseases would be unavoidable. Whether we like it or not, our own existence directly depends on insects and their ecological services. As M. Telfer (2004) put it: “Not everyone welcomes having ‘creepy-crawlies’ around but we should be grateful for what they do.”

In the following video, our special guest, Ms Roisin Stanbrook from the Manchester Metropolitan University, is taking about the ecological role of dung beetles in Kenya.

The presented story is based on: Logunov D.V. 2010. Nature’s recycling squad. Biological Sciences Review, 22(3): 22-25.

Further reading:

Berenbaum, M.R. (1995). Bugs in the system. Insects and their impact on human affairs. Helix Books.

Waldbauer, G. (2003). What good are bugs? Cambridge-London: Harvard University Press.

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Harelquin_Ladybird_Collection

The Manchester Museum’s collection of Harlequin Ladybirds recently acquired under the ongoing museum project ‘Thematic collecting’.

Recently, the Manchester Museum’s Entomology Department acquired some specimens of the Harlequin Ladybird, an invasive beetle species that appeared in Britain (Essex) in 2004 only, but is now a widespread and even dominant species of ladybirds in the UK.

 

Harlequin Ladybird – Harmonia axyridis (Pallas, 1773) (Coleoptera: Coccinellidae) – is a beetle species in the same family with the Seven-spot and Two-spot Ladybirds, both being considered gardener’s best friends as natural enemies of aphids and other garden pests. Harlequin Ladybird was deliberately introduced from east parts of Eurasia, where it is a native species, to many places of continental Europe as a biological agent to control aphids (=greenflies) and scale insects. As Harlequin Ladybird has excellent dispersal abilities (by means of flight), it was just the matter of time until it could have reached the British Isles.

A number of factors have contributed to the successful establishment and dominance of this ladybird species in the UK, particularly, its high reproductive capacity and ability to live in most available habitats. Harlequin Ladybird is also a voracious predator that can feed on other ladybird species.

The UK Ladybird Survey is a citizen science initiative that was launched in 2005, right after the first records of Harlequin Ladybird in Britain had been done. This programme is aimed at encouraging people across Britain to track the spread of Harlequin Ladybird (and other ladybirds) across the UK and submit their records online. Based on this survey, it is clear that by 2014 the Harlequin Ladybird has extended its range by almost half of the country. A decline of seven native ladybird species, which is correlated with the arrival of Harmonia axyridis, has also been demonstrated.

How to control this species and its spread in the UK is a bit unclear. Harlequin Ladybird produces a special, aggregation pheromone to attract other individuals to overwinterwing habitats. It has been proposed to use this pheromone within a network of traps in order to physically withdraw Harlequin Ladybirds from the environment. However, the cost of managing such traps is potentially too high to be feasible. The use of natural enemies of Harmonia axyridis, such as the ectoparasitic mite (Coccipolipus hippodamiae) that is capable to induce sterility in females of Harlequin Ladybirds, has also been considered, but alas with no practical applications so far. Therefore, this species is likely to be staying in the British Isles, apparently becoming another ‘native’ ladybird species with which we are to live (as it already happened with many other insect, crustacean and mollusc species).

Harelquin_Ladybird_Map

The occurrence of Harlequin Ladybirds in Britain from 2004 to 2014 (one dot is equal to 10-km square), after Roy & Brown (2015).

In the following interview, Don Stenhouse, the Curator of Natural Sciences at the Bolton Museum, will share with us his own experience in studying the Harlequin Ladybird.

A full story of the Harlequin Ladybird in the UK can be found in the following paper:

Roy H.E. and P.M.J. Brown (2015), ‘Ten years of invasion: Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) in Britain’ – Ecological Entomology, 40(4): 336–348; online at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4584496/

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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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A new photographic exhibition devoted to complex interrelations of humans and neotropical nature has been opened on the 3rd floor of the Manchester Museum. A brief Summary of the exhibition is given below:

The Ecuadorian Amazon is one of the most endangered regions of our planet. Many people want to protect the biodiversity that remains, but the reality on the ground is a complex dilemma. Economic necessity means that trees are valued for their timber more than for their crucial role in the ecosystem. Scientist and photographer Johan Oldekop, who was originally trained as a biologist at the University of Manchester (UK), studied the complex interaction between social and conservation issues in Ecuador during 2006-2011. As a scientist, Johan is interested in the socio-economic factors and land-use in indigenous Kichwa communities and their effect on the biodiversity of Ecuadorian Amazon. This exhibition presents his findings through his own stunning photographs combined with specimens from the Manchester Museum’s entomology and botany collections.

The exhibition will be opened until the beginning of June, 2013. Everyone is welcome!

Here are a few shots taken just after the opening of this exhibition.

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Dr Dmitri Logunov of Manchester Museum has been working closely with Tracy Hurst, a Visual Arts student at Salford University. She is creating a piece of artwork focussing on self portraits. However, these are not paintings or drawings.

Tracy invites people, curators, artists, students and complete strangers to chew a piece of bubbly gum. She  takes the chewed gum and creates stone plaster versions. Each piece of sculpture is classified using the three label system employed by entomologists. The pieces are then pinned into a wooden collectors case.

Each specimen has a latin name created for them, in Dr Dmitri Logunov’s case it is, ‘dimitri-vir ingenious de cimex,’ his Accession Lot Number is, F3313, the locality is ‘Manchester Museum’ and the habitat is classed as ‘Naphthalene’.

The specimen taken from Tracy's Tutor at Salford University

The  work is still in progress but will be available to be viewed by the public at Salford University from 3rd June 2010.

Dmitri is unwrapping the gum.

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Elephant Beetle (Megasoma elephas) is a large striking beetle, belonging to the scarab family and originating from the lowland rainforests in Central and South America. Beetles range between 70-120mm long (or over). The males are usually two/three times bigger than females and their weight can exceed 50-70g.

This is 35 times bigger than the weight of the smallest known mammal, Thailand’s bumblebee bat, which is 11mm long and about 2 grams weight.

The Elephant Beetle males have the large, graceful horns, protruding from their heads, like a trunk of the elephant (this is why their name). The males’ horns purpose is to fight other males for feeding or breeding sites.

Elephant Beetle’s larvae develop in large decaying logs and take up to four years to develop into an adult beetle. The life span of an adult beetle is around four months. Habitat destruction by the man, particularly clear-cutting when large trees are removed, is the main threat to this beetle in nature.

The photographed male is just one specimen from the large Manchester Museum’s collection of scarab beetles, numbering over 3,000 species.

The large male of the Elephant Beetle; it may take up to 4 years to reach maturity.

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