Beetles (Coleoptera)

[All pictures of garden wildlife on this page are thumbnails. Click on any thumbnail for a large format to be displayed. Scientific names of the species is always mentioned in the photograph's captions. If an English name for the species exists then it is specified. Some species have an additional page containing more photographs accessible via a weblink.]

See Gardensafari beetle pages grouped by families:

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 (Coleoptera)

No insect group counts more species than beetles do. Beetles have two pairs of wings although some species make the impression of being wingless. The front pair of wings is fully made of chitine which is extremely tough and therefore cannot be used for flying. We call them shields and one of their tasks is to protect the real wings that are located underneath the shield. If you catch a lady bug and put it on your hand pointing upwards, the lady bug run to find the highest point. When reaching the highest point it will open the shields, reveal the real wings and immediately 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 uncovered. The real wings are folded under the remains of the shields, similar to earwigs'. 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. In contrast, Rove Beetles, to the right have very small shields.

Beetles are divided into numerous families. Some of these can be recognised without problems, such as weevils which are 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 they are capable of completely destroying the wooden construction of buildings. If you have a pond in your garden, this will regularly be visited by some water beetles.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 some fungi as well. Beetles are not very impressive in size. The maximum is 20mm by 8 centimeters is reached by the giant tropical Goliath Beetle that is a relative of our May Chafer. The majority of species hardly ever reaches 1 centimeter, while many species don't even measure a millimeter! The biggest species that visited my garden so far is the famous May Beetle, which reaches about 3 centimeters. On Gardensafari pages the smallest beetle is Anthrenus pimpinellae, a relative of the infamous Museum Beetle. Even smaller species can be found in my garden, but most of these are too small for my cameras to capture a presentable image of.

This Skin Beetle to your left just reaches about 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 backgrounds of their habitat. Many groundbeetles are nocturnal animals and plain black. Like other insects, beetles may make 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 other colours from mixing the base colours 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. The structure of chitine refracts the light making an effect of green and blue shiny colours. You may compare this phenomenon to the breaking of light in a drop of oil floating on water. The structure of chitine varies from species to species giving them their own unique pattern and colours. The colours vary according to the amount of light or the angle you look at the animal. Therefore each individual has its own unique colours. We call this structural colouring. Some beetles decorate themselves in a third way: they produce colouring powder which they wear on their shields. This method is especially popular among weevils. This powder, like lipstick, wears off in time 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 which explains why many black beetles have a blue or green cast especially visible 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 cover of armour beetles are covered with. The Shield Beetle to your left will fully hide under his shield when sensing danger, much like a tortoise does.

One of the frequently asked questions about beetles concerns their age. How long does 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: egg-larva-pupa and adult. The period of time spent in the egg stage is not taken into consideration. Like in birds, an insect is supposed to be born at the moment it crawls out of the egg. So we have to measure an insects' life span by measuring how long it lives from the moment it comes out of the egg to the moment it dies. But even then things get very complicated. A May Bug for instance may live for merely two years or just as well it may reach the respectable age of 8 years. When conditions are optimal, 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 ground they usually live for about 4 to 5 weeks. Females will live a little longer than males because after mating the eggs need some time to ripen in the body of the female. By then the male is already dead after having fulfilled his duty. In captivity an adult of May Beetle can live much longer provided it is deprived of a possibility to mate. If you take a good care of a newly born May Bug it can keep you company for as long as three years! As soon as the male mates it dies within a couple of days. Females die right after depositing the eggs. In Western Europe there are only very few beetles that live for over a year as an adult. Some brown weevils do that but all others will die relatively quickly. Moreover our mild winters force most insects to overwintering. There is not enough food for all animals to feed so all bodily functions are suspended and the animals wait for better times to come. In southern parts of Europe and in Northern Africa the hot and dry part of summer are more of a challenge to beetles than winters. 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 which can hardly be considered nutricious diet. They may live inside a tree or joist for as long as twelve years before crawling out 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.

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 with identifying various species.