COLEOPTERA, Misc. Families of Coleoptera -- [Latest Classification]
Clausen (1940) reported on several families of Coleoptera that are associated in varying capacities with ants, some are definitely known to be predaceous on the ant broods, and others that are principally scavengers. These were Clavigeridae, Brentidae, Pselaphidae, Leptinidae and Paussidae. Park (1929) considered that Leptinus testaceus Muell., and possibly the entire Leptinidae, exhibit a facultative parasitism. Some Brentidae and Cryptophagidae are found in bark and wood under conditions that indicate they might be predaceous on other insects occupying the same habitat.
Many families of Coleoptera exhibit predaceous feeding behavior, and probably includes the majority of all insect predators. Species of Adephaga families Carabidae, Dytiscidae, Cicindelidae and Gyrinidae are almost all predaceous. They feed generally on insects of suitable size that occur in the habitat, but they attack many other forms of small animal life as well. In Polyphaga, the principal predaceous groups are Silphoidea (Silphidae), Staphylinoidea (Histeridae and Staphylinidae), Cantharoidea (Cleridae, Lampyridae, Cantharidae), Mordelloidea (Meloidae), and Cucujoidea (Coccinellidae). Even though most are general feeders, certain families are very much restricted in host preference. Silphidae normally feed on larvae of Diptera present in decaying animal flesh, while most Lampyridae, in both larval and adult stages, feed mainly on snails, earthworms, etc. Most Meloidae are predaceous on eggs of Locustidae in the soil, while several species develop in the cells of bees. The large family Coccinellidae, although having some phytophagous species, attacks mainly Coccidae, Aleyrodidae and Aphididae. In crop pest control, the Carabidae and Coccinellidae are of especial importance (Clausen 1940/1962).
A parasitic life style is not so common in Coleoptera as it is in Hymenoptera and Diptera, with ca. 8 families showing this behavior. Most species of the small family Leptinidae exhibit a facultative parasitism, and in the Staphylinidae many species of the Aleocharinae (Baryodma, Coprochara and Aleochara) are parasitoids of Diptera puparia. In Cleridae, several species of Hydnocera are parasitoids, and some Trichodes seem to develop in the same way. The Ripiphoridae are entirely parasitic on hymenopterous larvae and cockroaches. Some species of Colydiidae (e.g., Deretaphrus and Bothrideres) are considered parasitic, which is true also in Catogenus of the Passandridae. A few species of Anthribidae of the genus Brachytarsus are considered parasitic inasmuch as the larval food is strictly limited to the eggs beneath a single coccid host and the stimulus for oviposition is provided by the scale host itself rather than by the eggs. A few Coccinellidae, only those which attack the larger monophlebine Coccidae, may also be thought of as parasitic because the larva may develop entirely at the expense of a single host individual (Clausen 1940/1962).
There are few internal parasitoids among Coleoptera, except in the Ripiphoridae, where it is normal for all species. Among species attacking cockroaches the entire feeding period is passed internally, while in those attacking larvae of Hymenoptera, the internal phase is restricted to the latter portion of the 1st larval instar and the following instars are external feeders. Internal parasitism by Colydiidae is suspected, especially as isolated records show larvae being collected from pupae of Chrysobothris.
Parasitic Coleoptera show a considerable uniformity in behavior and the manner of development. In the families Ripiphoridae, Staphylinidae and Meloidae, all species deposit their eggs apart from the host stages on which development is to occur, placing them in the soil, in host galleries, or on foliage or blossoms. First instar larvae of parasitic Staphylinidae search for dipterous puparia in the soil of refuse habitat; those of Ripiphoridae attacking cockroaches, and probably a few Meloidae attacking bees, gain access to the host directly. The majority of species of the latter two families that attack vespoid wasps and bees, respectively, seem to require the services of a carrier to transport them from the vicinity of hatching to the cell, and this role is usually filled by the female wasp or bee (Clausen 1940/1962). Larval development among parasitic species also reveals certain points in common that are not possessed by the predaceous forms. A notable hypermetamorphosis occurs during larval development. The planidium type of 1st instar larva is of common occurrence in the Meloidae and Ripiphoridae and in parasitic representatives of several other families. Later larval instars assume a degenerate form in which the appendages are much reduced and the powers of locomotion are very limited or entirely lacking. Nonfeeding larval stages of Meloidae have not been recognized in other parasitic groups of Coleoptera with the exception of Drilidae (Clausen 1940/1962).
A early comprehensive review of the biology and behavior of entomophagous Coleoptera were presented by Balduf (1935). Böving & Craighead (1930-1931) provided an illustrated synopsis of the larval forms of Coleoptera, dealing especially with specialized larvae of a number of predatory and parasitic species.
The word Coleoptera comes from the Greek koleos, meaning "sheath"; and pteron, "wing", hence "sheathed wing." The order has more described species (ca. 400,055) than any other order of animals: this amounts to about 42 percent of all described insect species. These figures change as specialists become aware of the vast number of yet undescribed species. The largest taxonomic family, the Curculionidae (weevils) are Coleoptera. Only the Hymenoptera (bees, wasps) may have as many or more species.
Beetles occur in most habitats, but are not known from oceans or polar regions. They generally feed on plants and fungi, but also attack other invertebrates. Some species serve as prey of other animals, e.g., birds and mammals. Many species are pests of agricultural crops (e.g., Colorado potato beetle Leptinotarsa decemlineata, boll weevil Anthonomus grandis, red flour beetle Tribolium castaneum, and the cowpea beetle Callosobruchus maculatus). Others act as biological controls of some agricultural pests; e.g., Coccinellidae (ladybugs) are predators of aphids, scale insects, thrips, and other plant-feeding insects.
The beetles have a holometabolous life cycle; a prothorax that is distinct from and freely articulating with the mesothorax; the meso- and meta-thoracic segments fuse to form a pterothorax; there is a depressed body shape with the legs occur on the ventral surface; the coxae of the legs are recessed into cavities formed by sclerotised thoracic sclerites; the abdominal sternites are more sclerotised than the tergites; the antennae have 11 or fewer segments; and terminal genitalic appendages are pulled into the abdomen and not apparent when at rest. The anatomy is uniform, variations in appearance and function among the families.
An especially hard exoskeleton and hard forewings, or elytra, are present. The exoskeleton is made up of plates or sclerites, which are separated by sutures. This construction produces armored defences for the beetles while still maintaining flexibility. The elytra are not used for flying, but cover the posterior part of the body and protect the second pair of wings. They have to be raised hind wings to initiate flight. The flight wings have crossed veins and are folded after landing, often along these veins.
Some species do not fly at all, including some ground beetles (Carabidae) and some true weevils (Curculionidae). There are also some desert and cave-inhabiting species that are flightless. Many of these have fused elytra, which form a shield over the abdomen. In some families, both flying and the elytra have been lost, e.g., glow-worms (Phengodidae).
The mouthparts are like those of grasshoppers. The mandibles are large pincers that emanate from the head some beetles. They appear as pair of hard, frequently tooth-like structures that move horizontally to hold food or to serve as defence. Two pairs of finger-like appendages occur around the mouth in most beetles, which enable food to move into the mouth. These are formed from the maxillary and labial palpi.
The compound eyes may have great adaptability, as in Gyrinidae where the eyes are split to enable the insect to see both above and below water surfaces. Other species also have divided eyes, e.g., longhorn beetles (Cerambycidae) and weevils. There are also beetles that have notched eyes, and a few genera also have ocelli that are located back on the head.
The antennae are mainly organs of smell, but they may serve to test the physical environment. They are also important during mating or defence in some groups. Antennae vary, but are usually similar within any given family. Sometimes the males and females of a species have different antennal forms. Antennae may be clavate serrate, pectinate, filiform, geniculate, moniliform.
The legs have several segments ending in 2-5 smaller segments or tarsi. Claws usually are present on each leg. The legs legs are used mainly for walking, but they may serve for other uses as well. In the aquatic families Dytiscidae, Haliplidae and Hydrophilidae, etc., the legs may be modified for swimming and often bear rows of long hairs. Other beetles have fossorial legs that are widened and spined for digging. These adaptations are found among the scarabs, ground beetles, and clown beetles (Histeridae). The hind legs of some beetles, such as flea beetles (Chrysomelidae) and flea weevils (Curculionidae), are enlarged and serve for jumping.
One female may lay from several dozen to thousands of eggs during her lifetime. The eggs are usually laid in places where the larva will feed on hatching. The larvae are generally the feeding stage of the beetle life cycle. They tend to feed immediately upon emerging from their eggs. Some feed externally on plants, while others feed within their food sources. Many Buprestidae and longhorn beetles are external feeders. The larvae of other families are predacious like the adults (ground beetles, ladybirds, rove beetles). Although the larval period varies it can extend into several years.
Beetle larvae are quite distinct from other insect larvae because of their hardened, often darkened head, their chewing mouthparts, and spiracles along the sides of the body. They vary in appearance, especially between the families. Ground beetle larvae are flattened and very mobile, while some rove beetles have larvae that are campodeiform. Elateriform larvae (Elateridae & Tenebrionidae) appear as hardened worms with dark head capsules and tiny inconspicuous legs. Scarab beetles (Scarabaeidae) have short, thick larvae that are called grubs. All beetle larvae go through several instars. Some beetle groups, especially those with parasitic habits, have a planidium, which is highly mobile, eg., Meloidae and some rove beetles in the genus Aleochara.
Mating may involve intricate behavior. In burying beetles (Nicrophorus) combat may occur between males & females continue until only one of sex remains. Some males are territorial and will fiercely defend their territory from other males. These males may have horns on their head or thorax, to enhance their overall body size. Pairing is usually short but in some cases will last for several hours.
Parental care varies among the species, ranging from simply laying eggs under a leaf to certain scarab beetles, which make underground structures complete with a supply of dung for their young. Other beetles are leaf rollers, that laying their eggs in the curled plant material. Protection from predators includes mimicry, camouflage, toxicity, and active combat. Camouflage includes the use of coloration or shape to blend into the surroundings. This kind of protective coloration is common and widespread among beetle families, particularly those that feed on wood or vegetation, e.g., Chrysomelidae. In some of these species, sculpturing or colored scales or hairs change the beetle's appearance to resemble bird dung or other inedible objects.
Mimicry is another defence that often uses color or shape to ward off predators. A number of longhorn beetles (Cerambycidae) strongly resemble wasps, which helps them avoid predation even though the beetles may be harmless. This kind of defence also can be found in scarab beetles. Beetles may combine their color mimicry with behavioral mimicry, acting like the wasps they resemble. Species such as ladybirds, blister beetles, and lycid beetles may secrete toxic substances that make them unpalatable or poisonous. Large ground beetles and longhorn beetles may ward off predators with strong mandibles and/or spines or horns to forcibly cause a predator to stay away. Others, such as bombardier beetles (Carabidae), may spray liquids from their abdomen to repel predators.
Food habits vary among the species. Some are omnivores, eating both plants and animals. Others are specialised in their diet. Many leaf beetles, longhorn beetles, and weevils are host specific, feeding on only a single plant species. Ground beetles and rove beetles (Staphylinidae, etc.) are carnivorous and will catch and consume many other arthropods and small prey such as snails and earthworms. A few species have specific prey preferences. Decaying organic matter is a principal diet for many species. This can range from dung, which is consumed by coprophagous species (Scarabaeidae), to dead animals, which are eaten by necrophagous species (Silphidae). Some beetles that occur within dung and carrion are predatory, such as the clown beetles, preying on the larvae of coprophagous and necrophagous insects.
Adaptations to the environment vary greatly within the order. Aquatic beetles have several ways of retaining air beneath a water's surface. Beetles of the family Dytiscidae hold air between the abdomen and the elytra. Hydrophilidae have hairs on their under surface that retain a layer of air. Adult crawling water beetles use both their elytra and their hind coxae for air retention, while whirligig beetles carry a bubble of air when diving..
Many household, agricultural and forestry insect pests occur among the beetles. Of particular importance are the following:
The Colorado potato beetle, Leptinotarsa decemlineata, is a serious pest of potato plants. Crops may be devastated and only treatments of pesticides will mitigate damage.
Flour beetles are pests of stored cereal crops. They feed on wheat and other grains and are adapted to dry environments. They are serious pests of agriculture and have become highly resistant to insecticides.
The boll weevil, Anthonomus grandis, has done billions of dollars in damage since it first entered North America.
The bark beetles Hylurgopinus rufipes and Scolytus multistriatus, the elm leaf beetle, Pyrrhalta luteola, and other beetles attack elm trees. The bark beetles are important elm pests because they carry plant pathogens. The spread of certain fungus by the beetle has destroyed elm over a wide range of North America.
The death watch beetle, Xestobium rufovillosum, (Anobiidae) is a serious pest of older wooden buildings in Europe. It attacks hardwoods such as oak and chestnut, always in association with fungi.
The mountain pine beetle attacks mature or weakened lodgepole pine in North America, where it destroys vast stands of timber.
Some beetles are beneficial to humans, through their regulation of pest insect populations. Both the larvae and adults of some ladybugs (Coccinellidae) are predators of aphid. Other ladybugs feed on scale insects.
Ground beetles (Carabidae) are predators of many insects and other arthropods, including wireworms, fly eggs and caterpillars..
Plant-feeding beetles may also be beneficial in the control problem weeds. Some flea beetles of the genus Aphthona feed on Euphorbia esula (leafy spurge, Euphorbiaceae), a weed of rangeland in western North America.
Dung beetles (Scarabidae) have been used to reduce the populations of pestilent flies and parasitic worms that breed in cattle dung. The beetles reduce the availability of dung to breeding pests by rolling and burying it in soil. This also improves soil fertility and nutrient cycling.
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Arnett, R. H., Jr. & M. C. Thomas (2001). "Haliplidae". American Beetles, Volume 1. CRC Press, Boca Raton, Florida. pp. 138–143.
Arthur V. Evans, A. V., Charles Bellamy, and Lisa Charles Watson, An Inordinate Fondness for Beetles ISBN 0-520-22323-3
Beckmann, P. Living Jewels: The Natural Design of Beetles ISBN 3-7913-2528-0
Besuchet, C. 1956. Biologie, morphologie et systématique des Rhipidius (Col. Rhipiphoridae). Mitt. schweiz. Ent. Ges. 29: 73-144.
Béthoux, O. (2009). "The earliest beetle identified". = 83 (6): 931–937.
Chapman, A. D. (2009) (PDF). Numbers of Living Species in Australia and the World (2nd ed.). Department of the Environment, Water, Heritage and the Arts..
Cooter, J. & Barclay M.V.L. (eds.) (2006) A Coleopterist’s Handbook. Amateur Entomological Society. 439 pages. ISBN 0-900054-70-0
Entomological Society of America, Beetle Larvae of the World ISBN 0-643-05506-1
Grimaldi, D., Michael S. Engel, Evolution of the Insects ISBN 0-521-82149-5
Hammond, P., M. 1992. Species inventory. pp. 17–39 in Global Biodiversity, Status of the Earth’s Living Resources, B. Groombridge, ed. Chapman and Hall, London. 585 pp.
Harde, K. W. A Field Guide in Colour to Beetles ISBN 0-7064-1937-5 Pages 7–24
Khnzorian, S. M. 1957. A new representative of Rhipidius from Armenian SSR (Coleoptera, Rhipiphoridae). Dok. Akad. Nauk Armiansk. SSR. 24: 231-32.
Liebher, J. K. and Joseph V. McHugh in Resh, V. H. & R. T. Cardé (Editors) 2003. Encyclopedia of Insects. Academic Press.
Mosher, D. (December 26, 2007). "Modern beetles predate dinosaurs". Live Science..
Remo, A. R. (September 27, 2007). "Beetles infest coconuts in Manila, 26 provinces". Philippine Daily Inquirer.
Riek, E. F. 1955. The Australian Rhipidiine Parasites of Cockroaches (Coleoptera: Rhipiphoridae). Austr. J. Zool. 3: 71-94.
Ross H. Arnett, Jr. and Michael C. Thomas, American Beetles (CRC Press, 2001–2002). ISBN 0-8493-1925-0
Selander, R. B. 1957. The systematic position of the genus Nephrites and the phylogenetic relationships of the higher groups of Ripiphoridae (Coleoptera). Ann. Ent. Soc. Amer. 50: 88-103.
The Mountain Pine Beetle in British Columbia. Natural Resources Canada. August 19, 2008. Retrieved June 24, 2010.
White, R.E. 1983. Beetles. Houghton Mifflin Company, New York, NY. ISBN 0-395-91089-7