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So Last week I performed a HUGE 9 minute set for a Museums show off. People from all over the museums and libraries sector come and present a skit on something about their work or their museum. Now I choose to highlight the wonderful creatures that are maggots. They are all over my desk, I get sent them in the post, yesterday I, alongside a colleague, were hunting for them in the wildlife garden, I was rearing them from poo in the towers – in fact, maggots are very dominating in my job. And quite rightly so.
So I thought that I would convert that into a blog about these fantastic things and why the collections and the staff at the Natural History Museum are so important with maggot research! I have briefly touched upon maggots before but i thought that I would go into some more detail.
Let’s first clarify what a maggot is. The term maggot is not really a technical term and if you type in ‘what is a maggot’ on Google you get this!
To this date I have never heard someone describe something they yearn for as a maggot but who can say what will happen tomorrow with language fashions.
The maggot is a juvenile or, as I prefer to call it, the immature stage of a fly. These vary in form across the order from the primitive groups of flies (Nematocerans) to the more advanced groups (Brachycerans). The primitive groups have a more defined form in having a distinct head capsule with chewing mouthparts and we refer to these as Culiciform (gnat shaped).
Those more advanced flies whose larvae are without a head capsule and mouth parts that have just been reduced to hooks are called Vermiform (literally meaning worm shaped); and it is the later group that we generally call maggots!
We can label describe these head capsules further into three types;
And a housefly maggot (Acephalic larvae).
However for the purpose of this blog I will use the term maggots to include all Dipteran Larvae as there are some very important (and incredibly attractive) larvae from some of the more primitive groups. And they differ from most other insect larvae by the lack of jointed legs on their thorax. Beetles larvae are grubs, Butterflies and moths are caterpillars, bugs just have mini-versions of the adults, but they all have jointed limbs.
Above are some of the more incredible images of a cranefly larva. But these are not the heads of the cranefly larvae but rather their anal or posterior spiracles (breathing tubes). Anytime I need cheering up I flick through images of posterior spiracles.
Most people just view the larvae from either above or parallel but these are from bottom on! (these above diagrams are from the brilliant book by Kenneth Smith on Identification of British Insects) but as you can see some of the more interesting features are from this angle.
These spiracles form part of a breathing system that enables the maggot to breathe whilst feeding. These vary across the fly group with there being 7 different set ups of the spiracles.
The above diagram from top left to bottom middle shows (by dots and circles) where the spiracles are on the body. Some systems are very common such as the amphinuestic set up being found in most Diptera whilst others are very specialised such as the proneustic systems (only found in some fungus gnats). Some of them have taken their spiracle and run with it (as it were). Check out the rat-tailed maggot below (larvae of a hoverfly).
Rat-tailed maggot (larvae of a hoverfly).
The mouth can concentrate on ingesting food solidly – just imagine 24/7 eating. Now the maggot stage is the one designed for eating. I often wonder what it would be like to have the lifestyle of a fly – born, eat, eat, eat, eat, eat, mate, die…..and therefore they don’t have to have all of the equipment of the adult.
As I have already mentioned the larvae of Diptera do not have legs as other groups do such as the moths or the ants. This is because they are highly specialised examples of precocious larvae i.e. examples of very early hatching. And this is what arguably has lead to the most diverse range of habitat exploitation of all insects. They are plastic; they can squeeze themselves into tiny holes and between surfaces and therefore take advantage of so many different food sources.
In the wonderful book by Harold Oldroyd – The Natural History of flies - there is a sentence that states that the larva and adult are more different from each other than many Orders of Insects. And so in many ways with many species you could argue that flies fit two lifetimes into one as they are often completely different, both in form but also in diet and habitat.
The Diptera team have been talking maggots a lot recently. One of us, Nigel Wyatt, is something of an expert already on most things maggoty, working on most commercial, consultancy and public queries relating to maggots.
I had one recently from a friend of mine. She is a vet and one of her colleagues works with Police Dogs. Her colleague was a little confused and concerned about a maggot that was defecated by one of the dogs as she had not seen one so large before. My friend immediately thought of me and sent it to the Museum in a little tube of alcohol. Despite the alcohol it was quite fragrant by the time it arrived on my desk but it was easily identifiable as a cranefly larvae. Now cranefly larvae are incredibly versatile in terms of their habitat – they live in moss, swamps, ponds, decaying wood, streams and soil but as I far as I know the inside of a dogs alimentary canal is not a known habitat. They consume algae, microflora, and living or decomposing plant matter, including wood and some are predatory but parasites they are not. This one had miraculously come through the entire digestive tract of a dog without being destroyed. No harm done except to ones nasal cavities.
However, cranefly larvae or leatherjackets as they are sometimes called have caused some problems to lawns due to them consuming grass roots. Wikipedia – the great font of scientific knowledge cites from Ward’s Cricket's Strangest Matches ‘In 1935, Lord's Cricket Ground in London was among venues affected by leatherjackets. Several thousand were collected by ground staff and burned, because they caused bald patches on the wicket and the pitch took unaccustomed spin for much of the season.’
Apart from the staff who help with identifications we are helping further with outreach by helping with development of a new, hotly awaited book on British Craneflies. Alan Stubbs (not the retired footballer but the rather more impressive Dipterist and all round Natural History Good Egg) and John Krammer (retired teacher and superb Cranefly specialist) have been working on this fantastic tome for a while now and we have all been trying and re-trying the keys to ensure that they work. Preparations of gentailia, wings and larvae have been undertaken at the Museum on both Museum specimens and ones donated by John, and images and drawings of these been done. Carim Nahaboo has been drafted in for some of the drawings so expect great things.
This is an adult Dolichopodidae but it is a fine example of Carim Nahaboo's artwork.
Flies and their offspring have a terrible reputation. People are disgusted by most of them. However, they are essential both for our health and habitat but also for telling us what is happening.
Dr Steve Brooks and his group at the Museum work on Chironomidae (non-biting midges), and more specifically the immature stages – their larvae. Chironomid larvae are quite primitive and as such have a complete head capsule which is … as the larval stages develop they shed their head capsules and grow new ones, and these discarded ones can be used to determine the environmental conditions of the habitat both now and in the past as well as monitoring heavy metals.
I first came to the Museum as a professional grown up thanks to Steve as I was conducting a study using Chironomids as indicators of environmental health as they are fantastic bioindicators. Many Chironomid species can tolerate very anoxic environments as they, unlike most insects, have a haemoglobin analog which is able to absorb a greater amount of oxygen from the surrounding water body. This often gives the larvae a deep red colour which is why they are often called blood worms. Although slightly fiddly as you have to dissolve the body in acid, the use of head capsules for identification (image above) is fairly straight forward. The little crown like structures that you can see are actually rows of teeth and these are very good diagnostic features. Steve has worked for a long time on the taxonomy of these species and his (and his groups) expertise has been used globally.
So as well as looking funky we can use them to tell us many things about the world of today and yesterday. More on maggots in the future.
In my last post I described one of my curatorial tasks here at the Museum: the re-housing of our extensive collections of hawkmoths, made up of around 289,000 specimens.
The re-housing of the Museum’s extensive collection of hawkmoths will keep me busy for the next few months (did I hear someone say years?)
In this post I would like you to meet the actual stars of this project, the hawkmoths themselves. Hawkmoths belong to the Lepidoptera family called Sphingidae, a relatively small family if compared with other families in the order Lepidoptera; so far there are 208 genera and 1,492 species described. Hawkmoths are insects belonging to the family Sphingidae in the order Lepidoptera. 208 genera and 1492 species of hawkmoths have been described so far. Top row (L-R): Deilephila elpenor (Elephant hawkmoth), Agrius convolvuli (Convolvulus hawkmoth), Elibia dolichus. Middle row (L-R): Cechenena sp., Hayesiana triopus, Agrius convolvuli (Convolvulus hawkmoth). Bottom row (L-R): Mimas tiliae (Lime hawkmoth), Hyles sp., Hyles lineata (Striped hawkmoth), Akbesia davidi.
Species belonging to this family usually have falcate (curved and hooked) wings and their body is characteristically streamlined. The majority of species have a very swift and agile flight, and hover rapidly in front of flowers feeding on nectar with their tongue, which is often very long.
The long tongue of many species of hawkmoths is mainly used to feed on nectar from flowers or occasionally, as in the case of this Argentinean Xylophanes schreiteri, on sweet breakfast leftovers! This photo was kindly provided by Tony Pittaway. Check Tony’s interesting websites, Sphingidae of the Western Palaearctic and Sphingidae of the Eastern Palaearctic, for more information and pictures of hawkmoths.
Hawkmoths caterpillars are large and have a curved horn on the rear end. When disturbed, they usually rear up with their anterior segments arched, in a manner reminiscent of the Egyptian sphinx. These two larval features explain why these moths are also known with the common names of hornworms and sphinx-moths, while the common name hawkmoth refers to the rapid flight and falcate wing shape of the adult.
Sphingid caterpillars have a horn of various shapes on the last abdominal segment. From top right clockwise: Cephonodes hylas, Dolbina inexacta, Eumorpha analis and Daphnis nerii (Oleander hawkmoth). All pictures by Tony Pittaway.
The beauty and elegance of hawkmoths have always been attractive to both scientists and the public; consequently these moths have become one of the most widely collected groups of insects.
The beauty and elegance of hawkmoths have always been attractive to both scientists and the public.
Hawkmoths are generally well represented in every insect collection, large or small, and they are frequently reared from caterpillars, which has helped in providing a great deal of information on their biology and life history. Most species are also readily attracted to artificial light sources and this helps in surveying them when conducting biodiversity inventories of an area, which in turn has provided us with considerable insights into their distributional patterns and ranges.
Many species of hawkmoths are attracted to artificial light sources.
The following pictures, taken from specimens in the Museum collections, show the ample variation that exists in size, shape, features and wing patterns among the different species in this family of moths.
The stunningly emerald green Euchloron maegera. This species is commonly distributed in all Sub-Saharan Africa.
Oryba kadeni is another wonderfully green hawkmoth. It’s characterised by very large eyes and relatively short antennae. This species is found from Belize southward to Brazil.
Some sphingids like dressing in pink, such as this lovely elephant hawkmoth (Deilephila elpenor). This species is relatively common and widely distributed. It occurs in all Europe (with the exception of northern Scandinavia, northern Scotland and parts of the Iberian Peninsula), eastward through temperate Russia to the Pacific coast, Korea & Japan. It is also found in China as far as the provinces of Sichuan and Guangdong. It is a common species in the UK.
Leucophlebia lineata is another pretty hawkmoth sporting a series of pink, yellow and white stripes on the forewings. This species is found from Pakistan through India and Sri Lanka, to eastern and southern China, down to South East Asia.
Neococytius cluentius is one of the largest hawkmoths with a wingspan that can reach 17cm, and a long tongue of up to 22cm. It occurs from Mexico to Argentina, and has also been recorded as a stray in north Illinois and south Michigan.
The record for the longest tongue belongs to Xanthopan morganii subsp. praedicta, a relatively large hawkmoth found in Madagascar famous for its long proboscis used for probing on flowers to feed on nectar. Thanks to its long proboscis, which can reach 25cm, this moth is well adapted for feeding from the flowers of star orchids, in which the nectar is kept at the bottom of a very long spur. While doing so the hawkmoth secures the pollination of the orchid.
On the other hand, the adult of the hawkmoths in the subfamily Smerinthini, such as this Laothoe populi (the poplar hawkmoth), have extremely reduced mouthparts and are unable to feed. This moth is well distributed across Europe, as far as southern Turkey and eastward through Russia, and as far east as Irkutsk. It’s probably the most common hawkmoth in the UK where the adults fly between May and July.
Sphingonaepiopsis gorgoniades with its 2-3 cm wing span is the smallest hawkmoth. It occurs in some countries in South-East Europe, Turkey, Ukraine, Southern Russia, Kazakhstan, Kyrgyzstan and Afghanistan. It has also been recorded in parts of the Middle East.
The hawkmoth Euryglottis aper reminds me a bit of one of those soft toy puppets. It is a very hairy species as it flies at elevation of up to 2800m in Venezuela, Colombia, Ecuador, Peru and Bolivia.
The Museum collection contains representive specimens of 207 genera and around 1,300 species of hawkmoths; a global coverage of 85%. Of the 289,000 specimens of Sphingidae held in the Museum collections, 113,000 are dry pinned and a further 176,000 are unset and still in their original envelopes. The Museum's collection is certainly the largest and most complete collection of sphingid in the world.
In the next post I will be featuring more pictures and information on other species of hawkmoths and I will also give a little bit of history about the original hawkmoths collection of the Natural History Museum. I hope you'll be back then.
Thanks for reading and I take this opportunity to wish all the readers a Merry Christmas and a very Happy New Year.
A friendly convolvulus hawkmoth I met on a recent trip to Bulgaria. Isn't he cute?
Some of the enquirers during the recent #askacurator day event on Twitter were curious to know what curators do every day in their work. Well, I suppose it really depends on the type of collections in their care, and curators in a natural history museum might deal with different tasks compared to curators in an art collection for example.
Around 35% of mine and of my colleagues’ working time is dedicated to re-housing specimens, which is the transferring of pinned specimens from outdated or transitory drawers into new, more permanent drawers.
Re-housing specimens of hawkmoths in the collection.
Many of the original drawers in our collections are not up to scratch with respect to the most recent guidelines of conservation and collections policy, therefore we are actively replacing them with refurbished or brand new drawers.
Once emptied, the majority of the old drawers are sent for refurbishment and then re-use in the collection; other old drawers, as well as many boxes that come in with acquisitioned material, are sold and the proceeds used to buy new drawers or furniture for the collection.
Many drawers in our collections still contain unsorted and often unidentified material; this is because new material has been regularly added to the Museum through fieldwork, donations and purchases since the very early days.
Drawer with unsorted moths recently collected in Bolivia.
Specimens are also often donated to our Museum and others are purchased.
We always identify specimens before transferring them into new drawers along with the identified material already in the main collection. Eventually, when newly re-housed drawers are created, they need new labels, and their location, with other important details, are recorded in our electronic database.
These are all necessary steps if we want to make sure our collections are useful and easily accessible. If you consider that our section is made up of more than 80,000 drawers, it is crucial for us and for our visitors to know precisely where a particular drawer is located.
Re-housed drawers in their new location. Each curated drawer has internal labels stating the scientific name of the species inside, and also two external labels specifying the content. It also has a unique number; these details are all recorded in our electronic database so that specimens can be easily found in our extensive collection.
One of my current tasks is the re-housing of the entire Museum collection of hawkmoths (Sphingidae), which contains “only” around 114,000 specimens housed in about 2,130 drawers, and an extra 176,000 papered specimens, still in their original envelopes, waiting to be mounted.
Before August 2008 the Museum’s collection of Sphingidae contained ca. 60,000 pinned specimens, the vast majority of which were from the Rothschild Collection, dated pre-1930.
An original Rothschild drawer with specimens of the Oleander Hawk-moth waiting to be re-housed into new drawers.
Then, thanks to the generous sponsorship of the Rothschild family, the de Rothschild family, the John Spedan Lewis Foundation, Ernest Kleinwort Charitable Trust and members of our public, the Museum was able to acquire one of the largest private collections of Sphingidae, the Jean-Marie Cadiou collection.
The Cadiou collection, which contained 53,000 pinned specimens and 176,000 unset and still in the original envelopes, doubled the size of the Museum's original holdings and has provided modern material that was lacking in our collection.
The Museum’s hawkmoth collection has been transformed by the arrival of the Jean-Marie Cadiou collection.
Follow me in the next few posts, where I will talk about both the original Museum and the recently purchased Cadiou sphingid collections. I will explain how the current curation of the important and comprehensive Museum’s collection of sphingid into modern unit trays and refurbished Rothschild drawers is taking place.
Thanks for reading.