The Full Wiki

Beetle: Wikis

  
  
  
  

Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.

Did you know ...


More interesting facts on Beetle

Include this on your site/blog:

Encyclopedia

From Wikipedia, the free encyclopedia

Beetle
Fossil range: 318–0 Ma
Pennsylvanian - Recent
Phyllobius calcaratus, a species of weevil
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Subclass: Pterygota
Infraclass: Neoptera
Superorder: Endopterygota
Order: Coleoptera
Linnaeus, 1758
Suborders

Adephaga
Archostemata
Myxophaga
Polyphaga
See subgroups of the order Coleoptera

Beetles are the group of insects with the largest number of known species. They are classified in the order Coleoptera (pronounced /ˌkoʊliˈɒptərə/; from Greek κολεός, koleos, "sheath"; and πτερόν, pteron, "wing", thus "sheathed wing"), which contains more described species than in any other order in the animal kingdom, constituting about 25% of all known life-forms.[1] About 40% of all described insect species are beetles (about 350,000 species[1]), and new species are frequently discovered. Estimates put the total number of species, described and undescribed, at between 5 and 8 million.[citation needed] The largest family also belongs to this order — the weevils, or snout beetles, Curculionidae.

Beetles can be found in almost all habitats, but are not known to occur in the sea or in the polar regions. They interact with their ecosystems in several ways. They often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Some species are prey of various animals including birds and mammals. Certain species are agricultural pests, such as the Colorado potato beetle Leptinotarsa decemlineata, the boll weevil Anthonomus grandis, the red flour beetle Tribolium castaneum, and the mungbean or cowpea beetle Callosobruchus maculatus, while other species of beetles are important controls of agricultural pests. For example, beetles in the family Coccinellidae ("ladybirds" or "ladybugs") consume aphids, scale insects, thrips, and other plant-sucking insects that damage crops.

Contents

Description

The name "Coleoptera" was given by Aristotle for the hardened shield-like forewing (coleo = shield + ptera = wing).[1]

A cockchafer with its elytra raised, exposing the membranous flight wings, where the veins are visible
Trogodendron fasciculatum, a clerid beetle with bright yellow antennae
The extremely colourful Golden Stag Beetle

Other characters of this group which are believed to be monophyletic include a holometabolous life cycle; having a prothorax that is distinct from and freely articulating with the mesothorax; the meso- and meta-thoracic segments fusing to form a pterothorax; a depressed body shape with the legs on the ventral surface; the coxae of legs recessed into cavities formed by heavily sclerotized thoracic sclerites; the abdominal sternites more sclerotized than the tergites; antennae with 11 or fewer segments; and terminal genitalic appendages retracted into the abdomen and invisible at rest.[1]

The general anatomy of beetles is quite uniform, although specific organs and appendages may vary greatly in appearance and function between the many families in the order. Like all insects, beetles' bodies are divided into three sections: the head, the thorax, and the abdomen. When viewed from below, the thorax is that part from which all three pairs of legs and both pairs of wings arise. The abdomen is everything posterior to the thorax. When viewed from above, most beetles appear to have three clear sections, but this is deceptive: on the beetle's upper surface, the middle "section" is a hard plate called the pronotum, which is only the front part of the thorax; the back part of the thorax is concealed by the beetle's wings. Like all arthropods, beetles are segmented organisms, and all three of the major sections of the body are themselves composed of several further segments, although these are not always readily discernible. This further segmentation is usually best seen on the abdomen.

Beetles are generally characterised by a particularly hard exoskeleton and hard forewings (elytra). The beetle's exoskeleton is made up of numerous plates called sclerites, separated by thin sutures. This design creates the armoured defences of the beetle while maintaining flexibility. The elytra are not used for flight, but tend to cover the hind part of the body and protect the second pair of wings (alae). The elytra must be raised in order to move the hind flight wings. A beetle's flight wings are crossed with veins and are folded after landing, often along these veins, and are stored below the elytra.

In some beetles, the ability to fly has been lost. These include some ground beetles (family Carabidae) and some "true weevils" (family Curculionidae), but also some desert and cave-dwelling species of other families. Many of these species have the two elytra fused together, forming a solid shield over the abdomen. In a few families, both the ability to fly and the elytra have been lost, with the best known example being the glow-worms of the family Phengodidae, in which the females are larviform throughout their lives.

Beetles have mouthparts similar to those of grasshoppers. Of these parts, the most commonly known are probably the mandibles, which appear as large pincers on the front of some beetles. The mandibles are a pair of hard, often tooth-like structures that move horizontally to grasp, crush, or cut food or enemies (see defence, below). Two pairs of finger-like appendages are found around the mouth in most beetles, serving to move food into the mouth. These are the maxillary and labial palpi.

The eyes are compound and may display remarkable adaptability, as in the case of whirligig beetles (family Gyrinidae), in which the eyes are split to allow a view both above and below the waterline. Other species also have divided eyes — some longhorn beetles (family Cerambycidae) and weevils — while many beetles have eyes that are notched to some degree. A few beetle genera also possess ocelli, which are small, simple eyes usually situated farther back on the head (on the vertexes).

Beetles' antennae are primarily organs of smell, but may also be used to feel out a beetle's environment physically. They may also be used in some families during mating, or among a few beetles for defence. Antennae vary greatly in form within the Coleoptera, but are often similar within any given family. In some cases, males and females of the same species will have different antennal forms. Antennae may be clavate (flabellate and lamellate are sub-forms of clavate, or clubbed antennae), filiform, geniculate, moniliform, pectinate, or serrate. For images of these antennal forms see antenna (biology).

Acilius sulcatus, a diving beetle showing hind legs adapted for life in water

The legs, which are multi-segmented, end in two to five small segments called tarsi. Like many other insect orders beetles bear claws, usually one pair, on the end of the last tarsal segment of each leg. While most beetles use their legs for walking, legs may be variously modified and adapted for other uses. Among aquatic families — Dytiscidae, Haliplidae, many species of Hydrophilidae and others — the legs, most notably the last pair, are modified for swimming and often bear rows of long hairs to aid this purpose. Other beetles have fossorial legs that are widened and often spined for digging. Species with such adaptations are found among the scarabs, ground beetles, and clown beetles (family Histeridae). The hind legs of some beetles, such as flea beetles (within Chrysomelidae) and flea weevils (within Curculionidae), are enlarged and designed for jumping.

Oxygen is obtained via a tracheal system. Air enters a series of tubes along the body through openings called spiracles, and is then taken into increasingly finer fibres. Pumping movements of the body force the air through the system.

Beetles have hemolymph instead of blood, and the open circulatory system of the beetle is driven by a tube-like heart attached to the top inside of the thorax.

Development

soil dwelling larva of a weevil, probably the vine weevil genus Otiorhynchus

Beetles are endopterygotes with complete metamorphosis.

A single female may lay from several dozen to several thousand eggs during her lifetime. Eggs are usually laid according to the substrate the larva will feed on upon hatching. Among others, they can be laid loose in the substrate (e.g. flour beetle), laid in clumps on leaves (e.g. Colorado potato beetle), or individually attached (e.g. mungbean beetle and other seed borers) or buried in the medium (e.g. carrot weevil).

The larva is usually the principal feeding stage of the beetle life cycle. Larvae tend to feed voraciously once they emerge from their eggs. Some feed externally on plants, such as those of certain leaf beetles, while others feed within their food sources. Examples of internal feeders are most Buprestidae and longhorn beetles. The larvae of many beetle families are predatory like the adults (ground beetles, ladybirds, rove beetles). The larval period varies between species but can be as long as several years.

Beetles may be preyed upon by other insects such as robberflies

Beetle larvae can be differentiated from other insect larvae by their hardened, often darkened head, the presence of chewing mouthparts, and spiracles along the sides of the body. Like adult beetles, the larvae are varied in appearance, particularly between beetle families. Beetles whose larvae are somewhat flattened and are highly mobile are the ground beetles, some rove beetles, and others; their larvae are described as campodeiform. Some beetle larvae resemble hardened worms with dark head capsules and minute legs. These are elateriform larvae, and are found in the click beetle (Elateridae) and darkling beetle (Tenebrionidae) families. Some elateriform larvae of click beetles are known as wireworms. Beetles in the families of the Scarabaeoidea have short, thick larvae described as scarabaeiform, but more commonly known as grubs.

All beetle larvae go through several instars, which are the developmental stages between each moult. In many species the larvae simply increase in size with each successive instar as more food is consumed. In some cases, however, more dramatic changes occur. Among certain beetle families or genera, particularly those that exhibit parasitic lifestyles, the first instar (the planidium) is highly mobile in order to search out a host, while the following instars are more sedentary and remain on or within their host. This is known as hypermetamorphosis; examples include the blister beetles (family Meloidae) and some rove beetles, particularly those of the genus Aleochara.

As with all endopterygotes, beetle larvae pupate, and from this pupa emerges a fully formed, sexually mature adult beetle, or imago. Adults have an extremely variable lifespan, from weeks to years, depending on the species.

Physiology and behaviour

Reproduction

Punctate Flower Chafers mating
A flower beetle, Eudicella gralli, from the forests of Central Africa. The iridescent elytra are used in indigenous marriage ceremonies.

Beetles may display extremely intricate behaviour when mating. Pheromone communication is thought to be important in the location of a mate.

Conflict can play a part in the mating rituals of species such as burying beetles (genus Nicrophorus) where conflicts between males and females rage until only one of each is left, thus ensuring reproduction by the strongest and fittest. Many male beetles are territorial and will fiercely defend their small patch of territory from intruding males. In such species, the males may often have horns on the head and/or thorax, making their overall body lengths greater than those of the females, unlike most insects.

Pairing is generally short but in some cases will last for several hours. During pairing sperm cells are transferred to the female to fertilise the egg.

Parental care varies between species, ranging from the simple laying of eggs under a leaf to certain scarab beetles, which construct underground structures complete with a supply of dung to house and feed their young. Other beetles are leaf rollers, biting sections of leaves to cause them to curl inwards, then laying their eggs, thus protected, inside.

Defense

Beetles and their larvae have a variety of strategies to avoid being attacked by predators or parasitoids. These include camouflage, mimicry, toxicity, and active defense.

Camouflage involves the use of colouration or shape to blend into the surrounding environment. This sort of protective coloration is common and widespread among beetle families, especially those that feed on wood or vegetation, such as many of the leaf beetles (family Chrysomelidae) or weevils. In some of these species, sculpturing or various coloured scales or hairs cause the beetle to resemble bird dung or other inedible objects. Many of those that live in sandy environments blend in with the coloration of the substrate.

Another defence that often uses colour or shape to deceive potential enemies is mimicry. A number of longhorn beetles (family Cerambycidae) bear a striking resemblance to wasps, which helps them avoid predation even though the beetles are in fact harmless. This defence can be found to a lesser extent in other beetle families, such as the scarab beetles. Beetles may combine their colour mimicry with behavioural mimicry, acting like the wasps they already closely resemble. Many beetle species, including ladybirds, blister beetles, and lycid beetles can secrete distasteful or toxic substances to make them unpalatable or even poisonous. These same species often exhibit aposematism, where bright or contrasting colour patterns warn away potential predators, and there are, not surprisingly, a great many beetles and other insects that mimic these chemically-protected species.

Large ground beetles and longhorn beetles may defend themselves using strong mandibles and/or spines or horns to forcibly persuade a predator to seek out easier prey. Others, such as bombardier beetles (within Carabidae), may spray chemicals from their abdomen to repel predators.

Feeding

A Fiddler Beetle feeding from a flowering Cotoneaster glaucophyllus shrub

Besides being abundant and varied, the Coleoptera are able to exploit the wide diversity of food sources available in their many habitats. Some are omnivores, eating both plants and animals. Other beetles are highly specialised in their diet. Many species of leaf beetles, longhorn beetles, and weevils are very host specific, feeding on only a single species of plant. Ground beetles and rove beetles (family Staphylinidae), among others, are primarily carnivorous and will catch and consume many other arthropods and small prey such as earthworms and snails. While most predatory beetles are generalists, a few species have more specific prey requirements or preferences.

Decaying organic matter is a primary diet for many species. This can range from dung, which is consumed by coprophagous species such as certain scarab beetles (family Scarabaeidae), to dead animals, which are eaten by necrophagous species such as the carrion beetles (family Silphidae). Some of the beetles found within dung and carrion are in fact predatory, such as the clown beetles, preying on the larvae of coprophagous and necrophagous insects.

Adaptations to the environment

Aquatic beetles use several techniques for retaining air beneath the water's surface. Beetles of the family Dytiscidae hold air between the abdomen and the elytra when diving. Hydrophilidae have hairs on their under surface that retain a layer of air against their bodies. Adult crawling water beetles use both their elytra and their hind coxae (the basal segment of the back legs) in air retention[2] while whirligig beetles simply carry an air bubble down with them whenever they dive.

Evolutionary history and classification

Sphaerius acaroides, a member of the small suborder Myxophaga

A 2007 study based on DNA of living beetles and maps of likely beetle evolution indicated that beetles may have originated during the Lower Permian, up to 299 million years ago.[3] In 2009, a fossil beetle was described from the Pennsylvanian of Mazon Creek, Illinois, pushing the origin of the beetles to an earlier date, between 318 to 299 million years ago.[4]

The four extant suborders of beetle are these:

These suborders diverged in the Permian and Triassic. Their phylogenetic relationship is uncertain, with the most popular hypothesis being that Polyphaga and Myxophaga are most closely related, with Adephaga as the sister group to those two, and Archostemata as sister to the other three collectively.

There are about 450,000 species of beetles — representing about 40% of all known insects. Such a large number of species poses special problems for classification, with some families consisting of thousands of species and needing further division into subfamilies and tribes. This immense number of species allegedly led evolutionary biologist J. B. S. Haldane to quip when some theologians asked him what could be inferred about the mind of the Creator from the works of His Creation that God displayed "An inordinate fondness for beetles."[5]

Impact on humans

Pests

Colorado potato beetle (Leptinotarsa decemlineata) larvae

Many agricultural, forestry, and household insect pests are beetles. These include the following:

Beneficial organisms

Coccinella septempunctata, a beneficial beetle
  • Both the larvae and adults of some ladybugs (family Coccinellidae) are found in aphid colonies. Other lady beetles feed on scale insects and mealybugs. If normal food sources are scarce, they may feed on other things, such as small caterpillars, young plant bugs, honeydew, and nectar.
  • Ground beetles (family Carabidae) are common predators of many different insects and other arthropods, including fly eggs, caterpillars, wireworms and others.
  • Plant-feeding beetles are often important beneficial insects, controlling problem weeds. Some flea beetles of the genus Aphthona feed on leafy spurge, a considerable weed of rangeland in western North America.
  • Dung beetles (Coleoptera, Scarabidae) have been successfully used to reduce the populations of pestilent flies and parasitic worms that breed in cattle dung. The beetles make the dung unavailable to breeding pests by quickly rolling and burying it in the soil, with the added effect of improving soil fertility and nutrient cycling. The Australian Dung Beetle Project (1965–1985), led by Dr. George Bornemissza of the Commonwealth Scientific and Industrial Research Organisation introduced species of dung beetle to Australia from South Africa and Europe and effectively reduced the bush fly population by 90%.

Some farmers develop beetle banks to foster and provide cover for beneficial beetles.

Beetles of the Dermestidae family are often used in taxidermy to clean bones of remaining flesh.

Beetles in ancient Egypt and other cultures

Ancient Egyptian scene depicting a scarab beetle
Beetle collection at the Melbourne Museum, Australia

Several species of dung beetle, most notably Scarabaeus sacer (often referred to as "scarab"), enjoyed a sacred status among the ancient Egyptians, as the creatures were likened to the major god Khepri. Some scholars suggest that the Egyptians' practice of making mummies was inspired by the brooding process of the beetle.[citation needed] Many thousands of amulets and stamp seals have been excavated that depict the scarab. In many artifacts, the scarab is depicted pushing the sun along its course in the sky, much as scarabs push or roll balls of dung to their brood sites. During and following the New Kingdom, scarab amulets were often placed over the heart of the mummified deceased.

Some tribal groups, particularly in tropical parts of the world, use the colourful, iridescent elytra of certain beetles, especially certain Scarabaeidae, in ceremonies and as adornment.

Study and collection

The study of beetles is called coleopterology (from Coleoptera, see above, and Greek -λογία, -logia), and its practitioners are coleopterists (see this list). Coleopterists have formed organisations to facilitate the study of beetles. Among these is The Coleopterists Society, an international organisation based in the United States. Such organisations may have both professionals and amateurs interested in beetles as members.

Research in this field is often published in peer-reviewed journals specific to the field of coleopterology, though journals dealing with general entomology also publish many papers on various aspects of beetle biology. Some of the journals specific to beetle research are:

  • The Coleopterist (United Kingdom beetle fauna)
  • The Coleopterists Bulletin (published by The Coleopterists Society)
  • Elytron (published by the European Association of Coleopterology)

See also

General references

  • Poul Beckmann, Living Jewels: The Natural Design of Beetles ISBN 3-7913-2528-0
  • Arthur V. Evans, Charles Bellamy, and Lisa Charles Watson, An Inordinate Fondness for Beetles ISBN 0-520-22323-3
  • Entomological Society of America, Beetle Larvae of the World ISBN 0-643-05506-1
  • David Grimaldi, Michael S. Engel, Evolution of the Insects ISBN 0-521-82149-5
  • Ross H. Arnett, Jr. and Michael C. Thomas, American Beetles (CRC Press, 2001-2). ISBN 0-8493-1925-0
  • K. W. Harde, A Field Guide in Colour to Beetles ISBN 0-7064-1937-5 Pages 7–24
  • White, R.E. 1983. Beetles. Houghton Mifflin Company, New York, NY. ISBN 0-395-91089-7

Cited references

  1. ^ a b c d James K. Liebherr and Joseph V. McHugh in Resh, V. H. & R. T. Cardé (Editors) 2003. Encyclopedia of Insects. Academic Press.
  2. ^ R. H. Arnett, Jr. & M. C. Thomas (2001). "Haliplidae". American Beetles, Volume 1. CRC Press, Boca Raton, Florida. pp. 138–143. ISBN 0-8493-1925-0. 
  3. ^ Modern Beetles Predate Dinosaurs, Dave Mosher, LiveScience.com, 26 December 2007.
  4. ^ Oliver Bethoux, The earliest beetle identified, Journal of Paleontology, vol. 83, no. 6 (Nov. 2009), p. 931.
  5. ^ Hutchinson, G. Evelyn (1959). "Homage to Santa Rosalia or Why Are There So Many Kinds of Animals?". The American Naturalist 93 (870): 145–159. doi:10.1086/282070. http://links.jstor.org/sici?sici=0003-0147(195905/06)93%3A870%3C145%3AHTSROW%3E2.0.CO;2-D. 
  6. ^ Inquirer.net, Beetles infest coconuts in Manila, 26 provinces
  7. ^ The Mountain Pine Beetle in British Columbia, Natural Resources Canada

External links


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

BEETLE (0. Eng. bityl; connected with "bite"), a name commonly applied to those insects which possess horny wingcases; it is used to denote the cockroaches (black beetles), as well as the true beetles or Coleoptera, the two belonging to different orders of Insecta. The adjective "beetle-browed," and similarly "beetling" (of a cliff), are derived from the name of the insect. From another word (0. Eng. betel, connected with "beat") comes "beetle" in the sense of a mallet, and the "beetling-machine," which subjects fabrics to a hammering process.


<< Ludwig Van Beethoven

Nikolaas Beets >>


Wikispecies

Up to date as of January 23, 2010
(Redirected to Alan Ackerman Beetle article)

From Wikispecies

(1913-2003) Beetle

American botanist


Bible wiki

Up to date as of January 23, 2010

From BibleWiki

(Heb. hargol, meaning "leaper"). Mention of it is made only in Lev 11:22, where it is obvious the word cannot mean properly the beetle. It denotes some winged creeper with at least four feet, "which has legs above its feet, to leap withal." The description plainly points to the locust (q.v.). This has been an article of food from the earliest times in the East to the present day. The word is rendered "cricket" in the Revised Version.

This entry includes text from Easton's Bible Dictionary, 1897.

what mentions this? (please help by turning references to this page into wiki links)

This article needs to be merged with BEETLE (Jewish Encyclopedia).
Facts about BeetleRDF feed

Simple English

Beetles
File:Colorado potato
Colorado potato beetle, Leptinotarsa decemlineata
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Subclass: Pterygota
Infraclass: Neoptera
Superorder: Endopterygota
Order: Coleoptera
Linnaeus, 1758
Suborders

Adephaga
Archostemata
Myxophaga
Polyphaga

Beetles are a kind of insect. Biologists call all beetles as a group Coleoptera. There are 350,000 different kinds (species) of beetles. Beetles live almost everywhere, but not in the ocean or in places that are very cold, such as the North Pole or South Pole.

People sometimes call some beetles by other names. Fireflies (also called lightning bugs) are actually beetles; so are ladybirds or ladybugs, which scientists call lady beetles.

Contents

Beetle bodies

In common with other insects, there are three main parts to a beetle's body: the head, the thorax (the middle part), and the abdomen (the back part). On the head, beetles have antennae (feelers), eyes, and a mouth. The legs and wings of the beetle are attached to the thorax. The abdomen of a beetle does not usually have special parts on the outside, but it has the beetle’s stomach and intestines inside. Like other insects, beetles have no internal bones, but instead have a hard exoskeleton on the outside of the body. The exoskeleton is made of hard plates, like pieces of armour.

Wings

[[File:|thumb|left|The back wings of a beetle are see-through. This beetle uses its back wings to fly. The hard front wings are lifted up.]]

File:Feldmaikäfer (Melolontha melolontha) w
The hard front wings of the beetle hide the back wings.

Beetles are different to other insects because of their wings. Beetles have four wings. The front pair (two wings) have evolved into hard covers or elytra. The back wings are used for flying. They are thin and need the front wings to protect them when at rest. Beetles lift their front wings out of the way in order to fly. Most other insects do not have this arrangement, but the true bugs also have hard front wings.

Not all beetles can fly. Some beetles do not have back wings, and some beetles cannot lift their front wings out of the way. Only a few beetles have no wings at all and can never fly. Beetles with no wings look similar to beetle larvae, so they are called larviform.[needs proof]

Legs

The legs of beetles help them to walk, run, swim, and dig. All beetles have six legs. Each leg is made out of several parts. The parts on the end of each leg are often the smallest. They are similar to feet but are called tarsi. The last tarsus (the singular of tarsi) of each beetle “foot” has one or two claws on the end of it. Most beetles use their legs to walk or run. Some beetle legs are flat and have long hairs on them. These kinds of legs are found on water beetles and are good for swimming. Beetles that often dig in soil have flat legs with spines or horns at the edges. Flat legs with horns are called fossorial legs. A few beetles have large hind legs, similar to those of grasshoppers, which help the beetle to jump. Flea beetles are an example of jumping beetle.

Sight and smell

Beetles have compound eyes, which means the two big shiny eyes on the head are actually made out of many smaller parts. Sometimes the two eyes are each divided in half so that it looks like there are four eyes. One beetle family, the whirligig beetles, has divided eyes so that when they are swimming they can see on top of the water and inside the water at the same time. A few beetles have extra simple eyes (usually two) called ocelli. The ocelli are on the top of the beetle’s head.

Because beetles have no nose, they use their antennae to smell things. Beetles also use their antennae to feel things around them. Some beetles use their antennae to fight other beetles or even to fight larger animals that want to eat them. Beetle antennae do not all look the same. Some antennae are long and thin, while others are short and wide. Thin antennae are called filiform antennae, and antennae that are wide on the end are called clavate antennae.

The mouth

The mouth of a beetle is very different from the mouth of a person. Most beetles have two hard mandibles at the front of their mouth which are a bit like teeth. Mandibles help the beetle eat by crushing and cutting food. In some beetles, the mandibles look like big pincers. Beetles also have four “fingers” around their mouth that push food into the mouth of the beetle. These fingers are called palpi.

Other

Beetles do not breathe air through their mouths; instead they have holes called spiracles in the sides of their bodies which lead to trachea, which act like lungs. Beetles do not have blood, but they have something like blood, called hemolymph. It flows in their bodies and is usually a green colour.

How beetles grow

[[File:|thumb|An example of a scarabaeiform larva]] Beetles start out as eggs that a female beetle lays. Some beetles can lay thousands of eggs during their lives. A larva comes out when an egg hatches. Most beetle larvae do not look like adult beetles. A beetle larva eats and grows larger until it changes and becomes a pupa. When the pupa opens, an adult beetle, sometimes called an imago, comes out. This way of growing up is called complete metamorphosis.

Beetles eat the most when they are larvae. Some beetle larvae eat the outside of plants; some eat inside plants. Some beetle larvae are predators, which means they hunt for other insects to eat. Other beetle larvae eat dead things, such as dead plants and dead animals.

Not all beetle larvae look the same. Some beetle larvae are flat and move very fast. To describe these larvae, scientists use the descriptive word campodeiform. Some beetle larvae look similar to hard worms with tiny legs. These have an elateriform shape. The larvae of click beetles are elateriform larvae. Click beetle larvae have a special name: wireworms. Other beetle larvae are short and very thick and are called grubs. Scientists say that grubs have a scarabaeiform shape. In a few beetles, the larvae change its shape after some time. Blister beetle larvae start out moving fast, such as campodeiform larvae, but end up slow and thick, more similar to scarabaeiform larvae.

What beetles do

Food

Beetles eat many different things including living plants, rotting plants, animals that may be dead or alive, and animal feces. Some beetles can eat both plants and animals, while others eat just one type of food. Beetles that can only eat one kind of thing are said to be host specific. Many leaf beetles and longhorn beetles are host specific.

Protection

Beetles are tough animals for their size. They are mechanically tough (the elytra), and have a variety of strategies to avoid being attacked by predators or parasitoids. These include camouflage, mimicry, toxicity, and active defense.

There are many animals that want to eat beetles and beetle larvae. Animals that eat other animals (and that eat beetles) are called predators. Sometimes beetles eat each other. Other insects and spiders sometimes eat beetles. Larger animals, such as birds and mice, also eat beetles. How do beetles protect themselves?

Some beetles live in places that are hard for predators to find. Some beetles, such as longhorn beetles, live in tunnels inside tree branches. Only special predators that are small enough to use the long-horned beetle tunnels can eat the longhorn beetles.

Other beetles do not live in special places but they have colours or shapes that make them hard to find. When beetles have colours so that predators cannot see them, this is called camouflage. Some leaf beetles are green so that they can not be seen when they are on green leaves. Some beetles have very complex colours so that they look like bird feces.

Sometimes beetles use colour to warn predators. Some beetles have black and yellow stripes so that they look similar to bees and wasps. Some beetles even behave similar to bees to confuse predators.

Beetles have a wide range of chemical defences. This applies to the larvae as well as the adult imago. Many beetles taste bad when predators eat them. Lady beetles taste bad. Lady beetles also have colours that warn predators that they taste bad: bright colours with dark spots often means a beetle has a bad taste. Some beetles with bright colours and dark spots or lines are actually poisonous. Blister beetles are so poisonous that if a horse eats only a few of them, the horse may die!

Very large beetles sometimes fight predators. Beetles that fight will often use their mandibles as teeth to bite their predators.

Reproduction

Beetles have sexual reproduction, which means males and females mate in order to make offspring.

Before reproduction, male beetles sometimes fight to claim a female. This especially happens with stag beetles: males will fight using their long mandibles.

Some beetles give special care to their eggs or larvae. Some scarab beetles, called dung beetles, roll balls of dung (feces) and put them in a hole in the ground. The female lays her eggs in the dung. When the eggs hatch, the larvae will eat the dung that their mother supplied for them.

Kinds of beetles

File:Staphylinus.
Rove beetles have short front wings (the red parts in this beetle's back) that do not cover their abdomen.

Different kinds of beetles can be divided into groups called families. There are many beetle families. The biggest families are listed here.

  • Ground beetles (family Carabidae) are often black and can be found under rocks. They eat other insects.
  • Leaf beetles (family Chrysomelidae) usually eat on the outside of plants.
  • Longhorn beetles (family Cerambycidae) have very long antennae. Most longhorn beetle larvae eat on the inside of plants.
  • Weevils (family Curculionidae) have long faces that look like the trunk of an elephant. Weevils eat plants.
  • Scarab beetles (family Scarabaeidae) have antennae that are wide on the end. Some scarabs are called dung beetles. Other scarabs are very colourful and eat plants.
  • Rove beetles (family Staphylinidae) have short front wings that do not cover their abdomen. Rove beetles eat other insects.

Beetles and people

Some beetles cause trouble for farmers and people in forests because they eat crops or trees. These beetles are called pests. One beetle that hurts crops is the Colorado potato beetle.

Other beetles help people; lady beetles (also called ladybirds and ladybugs) eat insects that hurt crops and trees.

People who study beetles are called coleopterists.

General references

  • Arthur V. Evans, Charles Bellamy, and Lisa Charles Watson, An Inordinate Fondness for Beetles ISBN 0-520-22323-3
  • Entomological Society of America, Beetle Larvae of the World ISBN 0-643-05506-1
  • Ross H. Arnett, Jr. and Michael C. Thomas, American Beetles (CRC Press, 2001-2). ISBN 0-8493-1925-0
  • K. W. Harde, A Field Guide in Colour to Beetles ISBN 0-7064-1937-5 Pages 7-24
  • White, R.E. 1983. Beetles. Houghton Mifflin Company, New York, NY. ISBN 0-395-91089-7

Other pages

  • True bug - These are insects that look similar to beetles.
Look up Coleoptera in Wikispecies, a directory of species

bjn:Karariangfrr:Kraaben (insekten)








Got something to say? Make a comment.
Your name
Your email address
Message