Beetles (Coleoptera)

All pictures of garden wildlife on this page are thumbnails. Click on a thumbnail for enlargement in format of 800x600 pixels. The enlarged photos are from 100 to 150KB in size. We normally use the animal's English name (if it has one). However the scientific name of the species is always mentioned in the photograph's captions. For some species an additional page containing more pictures is available.

Thanks to David Gould (UK), Johan Bogaert (B), Kees van der Krieke (NL), G. Sama (GB?), Frank Köhler (D), Adrian Ruicanescu (GB), Craig Phillips (GB), Boris Büche (D), Rob Westerduijn (NL), Arved Lompe (D), Christopher Majka (CA), Otto Merkl (H), Vitali Nagirnyi (Est), Denis Keith (F), Schott Laurent (F), Victor Shilenkov (RU), Keith Edkins (UK), Guido Bonamie (B), Bertin Boertjes (NL), Arie M. den Toom (NL), Gerrit Tyberghein (B), Jan Muilwijk (NL) en Hans Ehrenhard (NL) for helping us by identifying various species.

Our original Beetle Page got too big. Especially surfers using a modem had to wait a long time for the page to load. In January 2004 we decided to cut the original page into several new shorter pages. The old beetle page was transformed into an introductory page on the Coleoptera. If you are looking for a particular species or family of beetles, please use the picture navigation at the top of the page, or our search engine at the bottom of this page, or make your choice below:

1 Big Beetles, such as Ground Beetles, Diving Beetles and Scarab Beetles, 2 Soft-winged Beetles, such as Soldier Beetles and Soft-winged Flower Beetles, 3 Longhorn Beetles, 4 Click Beetles, 5 Leaf Beetles, 6 Weevils and Fungus Weevils, 7 Lady Beetles, 8 Various smaller Beetles, such as Woodworms, Rove Beetles, Mordellids and Skin Beetles.

Introduction to Beetles

No insect group has more species than beetles do. Beetles do have two pairs of wings, even though some species make the impression of being wingless. The front pair however is fully made of chitine, extremely tough and cannot be used for flying. We call them shields and one of their tasks is to protect the real wings, the ones used for flying, located beneath. Just catch a lady bug, put it on your hand pointing upwards. The lady bug will try to find the highest point and once there will slide away its shields, revealing the real wings. Immediately afterwards it will more or less elegantly fly away. Not all beetles have shields covering their entire body. In Western Europe lots of beetles are so-called Rove Beetles. They all have very short wing cases, leaving the greater part of the body naked. The real wings are folded under the remains of the shields, the same way earwigs do. Oil Beetles as well as a few Longhorn Beetles also have extremely small shields.

Most beetles have shields covering the whole body, like the Soldier Beetles to the left. However Rove Beetles, to the right, have very small shields.

Beetles are divided into a lot of families. Some of these can be recognised without problems, such as weevils, small beetles all with a very pronounced litte snout. Longhorn Beetles usually really deserve their name, for most of them do have extremely long antennae. The larvae of some longhorns live inside dry and old wood, including timber and are capable of completely destroying buildings. If you have a pond in your garden, this will regularly be visited by some water beetles. If the pond is of no interest to them they quickly disappear again, for like most other beetles they are able to fly. A few ground beetles though are so accustomed to running they lost their flying capabilities. With some ground beetles the shields actually grew together for better protection. The hard exetrior of beetles is made out of chitin. This is a very hard, strong and extremely light substance, found in all arthropods and in ome fungi as well. But even though this material may be light, insects are never very big. In beetles the maximum size is about 20 by 8 centimeters, such as the tropical Goliath Beetle, a relative of our May Chafer. The majority of species hardly ever reaches 1 centimeter, while many species even don't reach a millimeter! The biggest species we had in our garden so far is the famous May Beetle, which reaches about 3 centimeters. On our pages the smallest beetle is Anthrenus pimpinellae, a relative of the infamous Museum Beetle. Even smaller species can be found in our garden, but most of these are too small for our camera to handle.

This Skin Beetle to your left just reaches some 5 mm, while the May Chafer to the right reaches just over 3 cm.

Many beetles are beautifully coloured, while others are entirely black. Some species imitate wasps by being black and yellow, others have the same colours as the materials they normally walk on. Many groundbeetles are nocturnal animals and plain black. Like other insects, beetles may produce their colours in three ways. The first way of obtaining colour is by producing pigments which are mixed with the chitin. In this way the colours black, brown, yellow and red are produced and all colours that can be obtained by mixing these colours. These animals are fast-dyed. No matter in what amount of light or what angle you look at them, they always show the same colours. The greenish and blueish metallic colours found in many insects are produced in another way. Chitin itself is transparent. Keeping it that way the light would travel through it. But because of the structure of chitine, the light soon gets refracted, producing green and blue shiny colours. You may compare this to the breaking of light in a drop of oil floating on water. The structure of the chitine varies with each species, giving them their own unique look and colours. However the colours do vary according to the amount of light or the angle you use to look at the animal. Therefor the colours do vary in each individual. We call this structural colouring. Some beetles however use a third way: they produce a colouring powder which they put on their shields. This method is especially popular among weevils. This powder, like a lipstick, is not very enduring and must be renewed regularly. If not, the original colour will soon become visible at certain spots, making the beetles look rather worn out. By the way: beetles are not confined to just one way of colouring, they may use all methods at the same time, explaining why many black beetles have a blue or green glow over them, especially in sunshine.

The Weevil to the left looks worn out, for part of the green dye it is using has gone. The Longhorn to the right is fast-dyed though, for the colouring is caused by pigmentation within the chitin.

The chitin turns beetles into hard nuts to crack and is a very good protection from certain enemies. Yet a suit of armour like this has one disadvantage: it will not allow you to grow any bigger. That's why insects have a larval state. Larvae do not have a hard chitin skin and therefor may grow bigger. Their skin is rather soft and is changed each time the insects wants to grow bigger. Even though a beetle goes through the full cycle of development: egg-larva-pupa-imago, it may only grow bigger in the larval state. An extremely small May Bug is not a young animal as some believe, but an animal that suffered from lack of food during the larval state. Once out of the pupa, the insect has reached its biggest size! In the suite of armour there are just a few openings allowing the animal to live: the mouth, through which food is absorbed, the excretion hole at the back to get rid of useless stuff and the trachea, very small openings, usually on both sides through which air is inhaled. Insects do not have lungs. They simply inhale by means of these thrachea, tubes through which the air is transported into the body. The tubes get very narrow allowing oxygen to reach all cells of the body.

The chitin makes up the coast of armour beetles are covered with. The Shield Beetle to your left will fully retract under his shield when sensing danger, much like a tortoise does.

One of the frequently asked questions about beetles is the matter of age. How long will a beetle live? It is a very tough question to answer. Usually the question refers to the adult beetle, but that's unfair. The entire lifespan of a beetle consists of the four stages already mentioned: egg-larva-pupa and adult. The period spend in the egg stage usually is not taken into consideration. Like in birds, an insect is suppose to be born once crawling out of its egg. So we have to measure an insects life span by measuring how long it lives from the moment it crawls out of the egg to the moment it actually dies. But even then things get very complicated. A May Bug for instance may live for two years only, but may reach the respectable age of 8 as well. When conditions are very good, the development of the larva takes just two years. When food is scarce or not very nutricious it may take the larva 5 years to pupate. Then, when the adults crawl out of the soil they usually live for some 4 to 5 weeks. Females will live a little longer than males do, for after mating the eggs need some time to ripen in the body of the female. By then the male has already fulfilled his duty and will have died. However in captivity an adult May Beetle can live much longer, provided it is prevented from mating. A freshly born May Bug put into a tank and kept well fed may amuse you for some three years! However, given a chance to mate, the male will die after a couple of days and females right after depositing the eggs. In Western Europe there are only very few beetles that live for over a year once adult. Some brown weevils do, but all others will die rather quickly. Besides our winter forces most insects into overwintering. There is not enough food for animals to feed on, so all bodily functions are suspended and the animals wait for better times to come. In southern parts of Europe and in Northern Africa winter is no problem, but the heatest and dryest part of summer is. In these areas many insects do not overwinter, but oversummer instead. So, how long do beetles live? In some cases, as in many skin beetles, the whole lifecycle will take no more than three to four weeks. Some longhorns live on dry wood, not a very nutricious meal. They may live inside a tree or joist for up to twelve years, before appearing as an adult. However the adults hardly ever live over six months (not counting overwintering or oversummering). So generally speaking the life span of a beetle in moderate Europe varies from anything between three weeks to twelve years!

Grubs, the larvae of May Chafers and such, may live for some five years, chewing on not very nutricious grass roots, while some brown weevils live up to three years while adult.

All pictures © Hans Arentsen (info@gardensafari.net) and © Hania Arentsen (photog@gardensafari.net).

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