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Identification

5 Posts tagged with the identification tag
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Other names: Drugstore beetle, Bread beetle

 

Classification

Class             Insecta

Order             Coleoptera

Family            Anobiidae

 

The Bread beetle, Stegobium paniceum, also known as the Biscuit beetle (or the Drugstore beetle in the U.S.A.) is one of the commonest pest insects of stored food. It is able to feed on a variety of plant and animal products including bread and flour and even hot spices and drugs. However, this beetle is not harmful to health and despite its close resemblance to the Common furniture beetle or Woodworm beetle (in the adult stage), it does not feed on wood.

 

Identification

The adult beetles are usually noticed first.  They are small, between 2 and 4 mm in length, reddish-brown and, under magnification, reveal fine grooves running lengthways along the wing cases.  Furniture beetles (or Woodworms) are similar but are somewhat larger and darker and their antennae are shorter than the legs (in Bread beetles the lengths are similar). There are three flattened segments at the tip of antennae. The head is partially hidden by the pronotum (the plate that covers the upper part of the thorax). Biscuit beetles have large dark eyes.

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            Dorsal view                     Lateral view                  Ventral view       Biscuit (L) and Furniture beetle (R)

 

Photo credits: Siga / Wikimedia Commons. Line drawings © The Natural History Museum.

 

 

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Possible confusion

 

Furniture beetle (woodworm)

 

Anobium punctatum

Somewhat larger and darker brown, antennae shorter than legs.

Pronotum with obvious ‘hump’ like a monk’s cowl.

Larvae bore into wood, where they feed for 3-5 years.


Photo credits: Siga / Wikimedia Commons.

 

 

 

 

 

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Possible confusion

 

Cigarette beetle (Tobacco beetle)

 

Lasioderma serricorne

Antennae with many serrations, while Biscuit beetle has three large ones at the tip. Has much weaker punctures on the surface of the wing covers (elytra). Eyes easier to see from above. Different shape of pronotum.

 

Photo credits: Kamran Iftikhar / Wikimedia Commons

 

 

 

 

 

 

Distribution and habitat

The Biscuit beetle occurs in houses, stores, warehouses and kitchens throughout central and northern Europe, including the UK, sometimes in very large numbers. It is known as a cosmopolitan species.

 

Life cycle

In common with other beetles, this species passes through four life‑stages: egg, larva, pupa and adult (pictured below).  The speed of development through the life cycle depends on temperature, moisture, quality and abundance of food.  In cool temperatures (below 15ºC) there is only one generation per year, in moderate temperatures two, while at higher temperatures (above 23ºC) there may be five or more.larva.jpg

 


Eggs are laid by mated females on or near the foodstuff.  When the larva emerges from the egg, it is less than 1mm in length. In its search for food, it may bite into packaged or hidden food sources. The larva increases in size and, at about 5mm in length, it enters the pupal stage.  Before emergence as an adult beetle, a minimum of nine days is spent as the pupa in an oval shaped cell moulded by the larva using the food material.


Damage and control

Because the Bread beetle larva thrives in dark, warm, undisturbed places, it is essential to search thoroughly for the food‑source of the larva if adults are found wandering around.  Rarely-used dried-foods such as flour or spices are often the source of an infestation. Removing disused and old foodstuff should eliminate an infestation.

Adult beetles may be seen around fire‑places and air vents with no apparent food‑source available. These are likely to have come from nests of wasps or birds in the attic.  Beware also of bread in fire‑places that has been dropped down the chimney by birds.  With suitable hygiene, and by preventing access into the attic by nest‑builders, the successful eradication of this pest should be assured.

 

To find out more:

Info sheet on Cornell University website:

http://idl.entomology.cornell.edu/files/2013/11/Cigarette-and-Drugstore-Beetles-2014-ocf7nv.pdf

Another info page on University of Florida Institute of Food and Agricultural Sciences:

http://entomology.ifas.ufl.edu/creatures/urban/stored/drugstore_beetle.htm

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In the last few days you may have been lucky enough to see a shooting star as one of the year's biggest meteor showers was displayed in the skies over Britain. But does a meteor ever become a meteorite? And how do you know if you have found one? Well in this blog I will tell you a little more about meteors and meteorites,  what to do if you think you have found one, and how to find out more at Meteorites Day 2012, a special event at the Museum on 2 September.

 

Over the weekend from the 11 to 15 August the UK was treated to the height of a meteor shower recognised as one of the best and most reliable meteor showers in the northern hemisphere. The Perseid meteor shower happens every year between late July and mid August and at its peak can produce tens of meteors an hour.

 

Originating from the debris stream left by the comet Swift-Tuttle as it orbits the sun, the Perseids are so called because they often appear to come from the constellation Perseus - but as the number of meteors increases they can be seen all across the night sky.

 

You may think that this event would lead to an increase in meteorite discoveries that are reported to the Identification Service here at the Museum, but meteors are formed from very small particles of matter ejected from the comet, that burn up completely in the atmosphere. This means that if you see a meteor you are unlikely to find a resultant meteorite.

 

2012-0402 Iron Meteorite Tanzania (UNK)1.jpgA meteorite discovery from Tanzania

 

But what if you do think you have found a meteorite - what can you do about it? Well before you jump to conclusions there are a few simple tests you can do on your possible meteorite.

 

STEP ONE: Test to see if your discovery is magnetic

 

All meteorites have some degree of magnetism; even the stony meteorites have flecks of iron and nickel mixture throughout the rock that distinguishes them from terrestrial rocks. You should be able to detect the magnetism with an ordinary fridge magnet, so if your object is not magnetic at all - then it is most likely not a meteorite.

 

P1070568.JPGTest your object with a fridge magnet

 

STEP TWO: Check the density of your discovery

 

Meteorites, especially iron meteorites, tend to be far more dense than some of the more commonly mistaken terrestrial rocks, so if your specimen is light in your hand when you pick it up, then again it is unlikely to be a meteorite.

 

P1070574.JPGYour object should be heavy for it's size

 

STEP THREE: Look at the surface of your discovery

 

Meteorites are characterised by something called a fusion crust - when the meteorite comes through the atmosphere the intense heat of entry causes the surface of the meteorite to melt. So if you can see cracks and bubbles or even other bits of rock or mineral stuck to the outside of your discovery, then once again, it is unlikely to be a meteorite.

 

P1070575.JPGThe surface of your object should be smooth with no bubbles (right)

 

So what do you do if you have done these three tests and all three suggest that you have found a meteorite? Then bring it in to the Museum! On Sunday the 2nd of September the Museum are holding a 'Meteorites Amnesty' with members of our Earth Sciences department on hand and some genuine meteorites you can touch and compare against your own discoveries.

 

There will also be talks and activities throughout the day all about meteorites. However, if you miss this event, don't worry. Just send us a photo at the Identification Service email (ias2@nhm.ac.uk) or bring your specimen in on another day and we will let you know if you have a meteorite or a meteor-wrong!

 

Find out more about the Meteorites Day special event at the Museum

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Here in the identification service we don’t need a diary or calendar to know what time of year it is, in fact we don’t even have to look out of the window!  We can tell the time of year by trends in the enquiries we get by email, phone, through the post or on our forum. 

 

Many species of insect have a lifecycle that lasts for a year, with the larvae or nymphs around in one season, and the adults around in another.  Last year we blogged about the amazing bee fly and how it is a sure sign that spring is on the way, but it’s not the only enquiry with a strong seasonal distribution.

 

I searched our database and the forum for enquiries right back through the mists of time to 1992 to collect data on 3 of our common seasonal species – bee flies (Bombylius sp.), the excellently named cockchafer (Melolontha melolontha) and house spiders (Tegenaria sp.). 

 

seasonal enquiries.JPG

 

 

Bee flies

These amazing little critters are around in April and May making the most of the spring flowers.  The two species we see most often are the common bee fly (Bombylius major, see picture) and the dotted bee fly (Bombylius discolour).  They have a fascinating life cycle and you can find out more about them here -


 

 

 

Bombylius major 2.JPG

 

Cockchafers

No, we didn’t make that name up, the common English name for Melolontha melolontha is indeed the cockchafer.  Although they are beetles they are also commonly called May bugs, and you can see why from the graph above.  These large beetles emerge as adults in May or June after living in the soil as larvae for 3-5 years. They are strong though inelegant fliers and are attracted to light, meaning they often fly through open windows and gatecrash evening barbeques!  But don’t worry; they are not harmful to humans.  Find out more here  -

http://www.nhm.ac.uk/nature-online/life/insects-spiders/common-bugs/cockchafer/index.html

 

2011-0759 Melolontha melolontha DSC_0121.jpg

 

House spiders

There are several species of common house spider in the UK which are difficult to tell apart.  However, they all belong to the genus Tegenaria.  They are around all year, but are most commonly encountered between August and October when the fully grown males set out to find love.  This is when they are most likely to run out from under your sofa or turn up in the bath – just in time for Halloween!  You can find out more here -

http://www.nhm.ac.uk/about-us/news/2010/october/house-spiders-prefer-the-shed-shock85297.html

 

2007-1030 Tegenaria sp. 4 for web.JPG

 

On a more serious note this little project shows how the identification service records are a mine of fascinating and potentially useful information.  This data also shows that both bee flies and cockchafers emerged significantly earlier in 2011 than 2010, so it would be interesting to see how they fare in 2012 – keep your enquiries and observations coming in to our forum!

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You only have to browse through the Fossils and rocks forum to see how many of the suspected fossils put on there turn out to be something completely different! Fossil eggs, bones, turtles, ferns, footprints, you name it, natural rock and mineral processes can mimic it. We call these natural rock and mineral specimens that resemble or are mistaken for fossils "pseudofossils". This post doesn't seek to go through the most common look-a-likes, but if you google "pseudofossil" you will find many excellent guides out there.

 

This post is just some of my personal favourites from the last year. Fun and amazingly co-incidental pseudofossils are one of my favourite parts of my job in Earth Sciences identification.

 

2010-2444 mineral thought to be fossil bird head 003.jpg

"Fossil bird head"

 

It's got everything - neck, beak, even an eye. But this shape is created by the growth of a mineral upon the rock surface.

2011-0695 P1040137.JPG

"Fossil shark"

 

This shark shape, silhouetted in white against the dark background, would have me swimming for my life if I saw the silhouette peaking out of the sea. But it is just a chance area of cleaner white Chalk against a backdrop of Chalk discoloured by dirt and moss.

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"Fossil fish"

 

I can see what they mean, it looks like a guppy with a long flowing tail and fin. But this is a type of the rock flint known as banded flint. Banded flints form a series of roughly parallel lines such as this, which can create all sorts of misleading shapes. The cause is still not fully understood but the movement of water and silica through the flint is thought to be involved.

 

The rock flint can mimic any kind of fossil you can think of - bones, eggs, whole heads and bodies, you name it. Look out for a blog all about the wonders of flint coming soon!

 

2011-0058 dinosaur head pseudofossil 001.jpg"Fossil dinosaur head"

 

If this were a dinosaur, I can even see what kind it would be - one of the duck-billed hadrosaurs I reckon. Sadly, this is just the shape of the lump of rock, that had probably been exaggerated by weathering.

 

 

While writing this I've realised that these pseudofossils do have something in common after all. They all demonstrates one of the key things to appreciate when looking for fossils: don't look for the overall shape of an animal. This is because the soft parts of animals like muscle and skin only fossilise very rarely and in unusual conditions. You can assume you won't come across soft part preservation without knowing what to look for and where to look. To find fossils, look for the hard parts such as bones and shells, and bear in mind these are most often broken, mixed up and/or isolated.

 

Although we can say what these aren't, the hardest question to answer is, so why did the rock or mineral form or weather into exactly that shape? There are millions of rocks out there and so even if such coincidental resemblences are rare, there will still be plenty of pseudofossils. And of course those are the rocks that are going to catch your eye and get picked up.

 

So what should you look for? This page on our website has some good information and links for fossil hunting advice. And of course we will be happy to see whatever you find, whether rock, mineral or uncannily-vegetable-shaped-rock on the rock and Fossil forum here.

 

Happy fossil - and pseudofossil - hunting!

133

One of the first signs of spring for the Identification and Advisory service is a wave of intriguing descriptions of a mysterious garden visitor. Here are some from last year:

“A curious flying insect which was about 10mm long, hairy, beige/brown coloured, triangular in shape with a long snout which had the ability of flying backwards.”

“Approx 1 cm long, wing span twice body length, mix of light brown and black, teardrop shaped, hovers and darts at leaves and dead twigs, long spear-like proboscis approx half body length apparently non retractable”

“If I was to describe it compared to other animals it was a cross between a bee, a golden mole and a narwhal - but that sounds really silly.”

“Small (about 1/2 in long) humming insects. They were light brown with a furry appearance and had a spike at the rear and at the front. Their way of flying was to hover then move, very quickly, to a plant or another part of the garden. I could also hear the hum of their wings. They had to settle when feeding from the grape hyacinths, and I observed that their wings were like bee's wings (clear) and not like moths. Were these baby hawk moths?”

“I knew it was a hornet because it had a horn”

“It looks like a bat, but was the size of a wasp and had insect wings and legs. What is it?”

 

These are all descriptions of the same type of insect - bee flies.

 

There are 9 species of bee fly found in the UK, but the weird and wonderful creatures described above are from the genus Bombylius. The most common species is Bombylius major, and you can read more about its fascinating lifestyle here.

 

For serious bee fly enthusiasts the best book on the subject is British Soldierflies and Their Allies by Alan Stubbs and Martin Drake

 

07-445 Bee Fly - Bombylius major 1.jpgBombylius major

 

If your bee fly has a strong dark mark across the front half of its wings it is Bombylius major like the one above. If it has a spotty wing edge it is the rarer Bombylius discolor like the picture below. Both of these lovely images were sent in to us for identification by curious members of the public!

 

08-1027 Bombylius major 2.BMP

Bombylius discolor

 

So keep your eyes peeled for bee flies this spring, and share your pictures on our bug forum like these fine people: