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For educational purposes:--

Information on the basics of Entomology

 

Introduction                                                                                                                                                                                                                                                                           Contents

 

An Introduction To The Study of Entomology 1

Kingdom:  Animalia, Phylum: Arthropoda

Subphylum: Hexapoda: Class: Insecta: Order: Coleoptera

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Pteragota:  Holometabola

  Order:  Coleoptera (192 Families)

    General Summary

    Morphology & Habits

    Subdivisions & Classification

      Suborder:  Archostemata

      Suborder: Adephaga

         Geodephaga

         Hydradephaga

      Suborder:  Myxophaga

     Suborder: Polyphaga

        Staphyliniformia

        Elateriformia

        Bostrychiformia

        Scarabaeiformia

        Cucujiformia

 Additional Families

 Biological Control Projects

 Sample Examinations

    References      Citations

 

General Summary of Coleoptera

 

          Coleoptera include the beetles that have biting mouthparts; the fore wings are modified to form firm elytra.  The hind wings are membranous and folded beneath the elytra, and they are usually reduced or absent.  The prothorax is large and the mesothorax is greatly reduced.  They have complete metamorphosis.  The larvae are campodeiform or eruciform or generally apodous.

 

          The head of larvae is well developed and the mouthparts are of the biting type, about like those of the adults. The most primitive larvae are those of the campodeiform type (as found among the Cicindelidae (tiger beetles); Carabidae (ground beetles) and the Staphylinidae (rove-beetles». They are very active in movement and usually predaceous, with well-developed antennae and mouthparts, and a cuticularized exoskeleton. In the eruciform type found among plant-eating forms like the lamelllcom beetles, the legs are shorter, and the animal is less active in its foraging for food, the body bulkier and cylindrical.  In the apodous type that is found in the Curculionidae (the weevils), in which not only are the thoracic legs are lost but the antennae and mouthparts are reduced.  Apodous larvae usually live inside the soft tissues of plants or beneath the soil attached to roots.


          The relation that these larval forms bear to one another is indicated by the larval stages passed through in the life history of the oil beetle, Meloe, the larvae of which are parasitic on solitary bees of the genus Anthophora. The first instar is known as a triungulin. This is an active campodeiform larva that attaches itself to its host after searching actively for it. The second instar, which is enclosed with an abundance of pollen and nectar in the cell of the bee, is intermediate in form between the campodeiform and eruciform types, legs being present, but very small. The third stage is a legless grub. Thus, the form of larva in Coleoptera is related to the ease or difficulty with which food is obtained. The pupa is exarate and usually thin-skinned.   Obtect pupae may sometimes be found in Staphylinidae (
Borradaile & Potts, 1958).

 
          This large order of insects shows all manner of habits and food. Beetles occur in large numbers in water, soil, and plant tissues. Environments like dung, rotting vegetation, wood and fungi are never without prominent coleopteran fauna. A large number, such as many coccinellids (lady-birds), carabids, e.g. Carabus vio/aceus, and staphylinids, e.g. Ocypus o/ens, are carnivorous and beneficial insects. On the other hand, among the phytophagous forms are some of the most serious agricultural pests, the boll weevil, Anthonomus grandis, causing so much damage to the cotton crop in America that sometimes cotton production is postponed for a period of time in order to eradicate this pest. Among the weevils there are several species of Calandra that do great injury to stored grains. A large number of beetles cause damage to timber, probably the most notable being Xestobium rufovillosum, the death-watch beetle, destructive to structural timber.

 

          The order has two principal suborders, the Adephaga and the Polyphaga.  The Adephaga, are mostly carnivorous, and distinguished by filiform antennae, a five-jointed tarsus, and a larva of the campodeiform type, with a tarsus bearing two claws. To this group belong those families including the large water beetle Dytiscus, the ground beetles Carabus and Calosoma the tiger beetle Cicindela, and the aquatic whirligig beetles Gyrinus (Borradaile & Potts, 1958).

 

          The other suborder, Polyphaga, includes a large number of families grouped into several superfamilies, the members of which show great variation both in form and habit. There is a tendency towards reduction in the number of tarsal joints from 5 to 3, and though some forms have filiform antennae, clavate (clubbed), geniculate (elbowed), and lamellate (segments extended to form a 'book of closely arranged leaves or lamellae) antennae occur, as in the Coccinellidae, Curculionidae and Scarabaeidae respectively.  Larvae vary from the campodeiform to the legless grub, but where a tarsus is present it usually has only one claw.


          The Staphylinidae range from carnivorous to phytophagous habits, and, as adults, are characterized by the short elytra that leave the abdomen exposed. The larvae are campodeiform, closely resembling those of ground beetles, e.g. Ocypus.  Meloidae or oil beetles also have short elytra, but these being wider at the base than is the prothorax are readily distinguished from members of the staphilinid group.


          The Chrysome/idae or leaf beetles are all phytophagous. Their bodies are rounded and smooth, and are often highly colored with a metallic luster. Antennae of these beetles are filiform and quite short (e.g. Phy//otreta, the flea-beetle).


          Weevils belonging to the family Curcu/ionidae are easily recognized by their greatly extended head, forming a rostrum at the end of which mouthparts are borne. Anthonomus grandis, the cotton-boll weevil of America, and Ceuthorrhynchus, the turnip-gall weevil of England, are typical examples. The larvae are apodous.


          The chafer-beetles (Scarabaeidae) have lamellate antennae. Their legs are usually fossorial and bear 4-jointed tarsi. Characteristic of these is the fat-bodied eruciform larva, almost incapable of movement, and which feeds on roots, e.g. Melolontha.  Aphodius is a dung beetle whose larva develops in the faecal matter of farm animals.

 

          The family Coccinellidae (lady-birds) is of great importance, its members being carnivorous in young and adult stages, aphids and scale insects are included in their diet. The beetle is smooth and rounded, with the head concealed beneath the prothorax. The four-jointed tarsus appears to have only 3 joints, due to the small and hidden third joint, e.g. Coccinella.  Novius (Rodolia) cardinalis is a classical example of a predatory insect being used in the biological control of the scale insect, Icerya purchasi, of citrus trees (Borradaile & Potts, 1958).

 

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Morphology & Habits of Coleoptera

 

          The Coleoptera contain the largest number of insect species, with over 215,000 or over 40 percent of all known insects.  Their habitats include ground litter, underneath rocks, in logs, etc.  They are adapted to almost any environment on earth except the ocean and polar ice caps.  Their feeding habits range from foliage feeders to general predators.

 

          The greatest variation is shown among the larval stages.  Campodeiform larvae are very active, while scarabaeid larvae are circular and occur in the ground.  Elateriform larvae are long, straight and heavily chitinized, while apodeus larvae have no legs at all.  The pupae are of the exarate type and the mouthparts are all mandibulate or chewing.

 

          The fore wings are highly sclerotized to form elytra in which the venation has been lost.  The hind wings with venation present are large and folded or tucked underneath the elytra.

 

          The general body form is shown in Fig. ent60:

 

 

          The main taxonomic characters used for identification are the antennae and the tarsal formulae (e.g., 5-5-5, 5-4-3, 3-4-4, etc.)

 

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Subdivisions & Classification of Coleoptera

 

 

          Hundreds of years of collecting Coleoptera by enthusiasts and specialists have led to great sophistication in classification.  Some of the major groups are presented here as of 2010, but these may be modified as more information is obtained and disagreements among specialists are resolved.  The following discussion includes only the most common or important families of Coleoptera. For greater detail please refer to Borror et al. (1989), and for an expanded treatment of Coleoptera taxonomy with 192 families noted please see <Coleoptera (All Families)>. Additional information on <Habits>, <Adults> and <Juveniles> is included when available.

 

          The two largest Suborders of Coleoptera are Adephaga and Polyphaga.  The Adephaga has the smallest number of species.  Here the coxae divide the first abdominal segment.  This group is further divided into Geadephaga and Hydradephaga.  The Suborder Polyphaga has the most species and the coxae do not divide the first abdominal segment.  The group is separated according to the character of the Malpighian tubules, the spiracles on the eighth abdominal segment and the urogomphi [Please see Glossary for explanation of structures].

 

Suborder:  ARCHOSTEMATA

 

          Family Cupedidae. -- The reticulated beetles are a small group of beetles all of which bear dense scales on their bodies.  The elytra are reticulated and the tarsi with five segments.  The prosternum reaches backward as a narrow structure that lies in a groove in the mesosternum, similar to the click beetles.  Their habitat is primarily under the bark of trees.

 

 

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          Family Micromalthidae. -- The micromalthid beetles are a rare group with only a few species occurring in eastern North America.  Adults are small, 1.7-2.6 mm long, elongated with parallel sides.  Their color is shiny dark with yellow legs and antennae.  The tarsi have five segments.

 

 

          The life cycle is unusual as the larvae are paedogenic, enabling them to reproduce parthenogenetically, either viviparously or oviparously.  Their habitat is in the decaying wood of chestnut and oak.

 

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Suborder:  ADEPHAGA-- Geodephaga

 

          Family Cicindelidae. -- Cicindelidae <Habits>; <Adults> & <Juveniles> -- The tiger beetles are very active and nervous beetles with diurnal habits.  They are metallic in color and predaceous as both adults and larvae.  The larvae burrow in the ground whre they hold themselves fast to their burrows by a hook on the first abdominal segment.  Larvae will leap out after prey.

 

 

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          Family Carabidae. -- <Habits>; <Adults> & <Juveniles> -- The ground beetles are very active and nocturnal.  The bombardier beetle expels smoke when frightened.  Both adults and larvae are highly predaceous.

 

 

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Hydradephaga

 

          Family Dytiscidae. -- <Habits>; <Adults> & <Juveniles> -- The diving beetles are mostly predaceous.  They are very rapid swimmers.  Their crescent shaped mandibles are well developed.  Pupation is in an excavated cell in the earth adjacent to water.

 

 

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          Family Gyrinidae -- <Habits>; <Adults> & <Juveniles> -- The whirlygig beetles are small, active beetles that make circular patterns on the water.  Their eyes are formed in two parts:  one eye is in the air and the other in the water.  They are gregarious and both adults and larvae are predaceous.

 

 

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Suborder:  MYXOPHAGA

 

          Family Sphaeriusidae (Sphaeridae). -- The minute bog beetles are tiny, their length being only 0.5-0.76 mm.  They are oval, convex shining black beetles that can be found in mud and underneath stones near water, among the roots of plants and in moss.  Their tarsi have three segments and their abdomen is short and seems to have only three segments.  The first segment is triangular, the second a narrow band and the third taking up most of the abdomen.  The antennae are short and do not extend beyond the middle of the pronotum.

 

 

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          Family Hydroscaphidae. -- The skiff beetles are small and only 1.4 mm long with three-segmented tarsi.  The elytra are short in the manner of the Staphylinidae.  Antennae consist of nine segments with a one-segment club.  The abdomen has 6-7 visible sterna, the hind coxae are small and separated.

 

 

          Their habitat is in filamentous algae that occur on rocks in streams.  There are very few species known for this family.

 

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Suborder:  POLYPHAGA

 

          Internal morphology distinguishes this group of Coleoptera.  The functional characteristics of the eighth abdominal segment is used for distinctions with special functions occurring in some species and in others there are none.  The ninth abdominal segment may bear well-developed cercal structures and urogomphi are present in some larvae.  Urogomphi are fixed or movable cercuslike processes on the last segment of the larvae.  Sometimes these are called pseudocerci or corniculi.

 

          The Polyphaga are divided into an additional five Infraorders: (1) Staphyliniformia, (2) Elateriformia, (3) Bostrychiformia, (4) Scarabaeiformia, (5) Cucujiformia,

 

Infraorder:  Staphyliniformia

 

          Family Staphylinidae. -- <Habits>; <Adults> & <Juveniles> <Identification> -- The rove beetles are capable of effective flight even though the wings are extensively folded under extremely short elytra.  There is a simiulated stinging mechanism on the abdomen.

 

 

          The family is comprised of mainly predatory species, the importance of which has been stressed for biological control (see <Staphylinidae>).

 

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          Family Histeridae. -- <Habits>; <Adults> & <Juveniles> -- The hister beetles are small, 0.5-10.0 mm long broadly oval insects that are usually shining black in color.  Their elytra are squared off at the apex, which exposes one or two apical abdominal segments.  They have elbowed and clubbed antennae.  The tibiae are dilated with spines located the anterior ones.

 

 

          These beetles are usually found around decaying organic matter in animal dung, carrion, where they feed on other small insects.  Some flat species are found under loose bark of tree stumps and some live in ant or termite nests.  There are also elongated or cylindrical species found in galleries of wood-boring insects.  When agitated they may draw in their legs and antennae to become motionless, as these appendages fit tightly into shallow grooves on their ventrum.

 

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          Family Hydrophilidae. -- <Habits>; <Adults> & <Juveniles> -- The diving or water scavenger beetles are often confused with the coleopterous family Dytiscidae, although the latter have filamentous antennae instead of clubbed antennae as in this group.

 

 

          The antennae are used to trap air for these insects when they are submerged under water.  They contain hydrofuge hairs for this purpose.  Air is also trapped underneath their wings.

 

          The adult hydrophilids are scavengers, but their larvae are very common predators.

 

          The legs are modified with hairs to facilitate swimming.  A long spine, which is an elongation of the prothorax, may prick one's fingers if handled and serves as a defensive mechanism.

 

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          Family:  Silphidae. -- <Habits>; <Adults> & <Juveniles> -- The carrion beetles are quite large insects that may be brightly colored and inhabit areas around dead animals.  Their body is soft and flat.  The antennae are clubbed  and the tarsi have five segments.  Their size ranges from 3-35 mm.

 

 

           Some species excavate the soil beneath carcasses thereby accomplishing burial, which also has given them the name "burying beetles."  After the carcass is buried the females lay eggs on it, and both adults and larvae feed on the carrion.  Other species occur in fungi and in ant nests, and some species feed on fly maggots that inhabit carrion.  Borror et al. (1989) report that Nicrophorus spp. larvae are fed carrion that is regurgitated by the parent beetles.

 

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Infraorder:  Elateriformia

 

          Family Elateridae. -- <Habits>; <Adults> & <Juveniles> -- Among the click beetles the larvae do not have a closing mechanism for their spiracles.  The clicking sound is brought about by a ventral spine on the prothorax that is inserted in a groove in the mesothorax.  The head is very small, and there is a much enlarged prothorax.

 

 

          The larvae are mainly carnivorous, and require 3-6 years to complete their life cycle.

 

          Some click beetles produce light and are phosphorescent.  These lights may flash on and off.  Light production in insects involves a complicated chemical process and the light is almost pure light, consisting of 98 percent light with only two percent heat.

 

 

          Much attention has been paid to controlling elaterids.  Over planting a field allows for some destruction by the larvae.  Seed treatment with chemicals has been effective and is inexpensive.  Soil treatment is effective and endures for four or five years.  Crop rotation is a very effective control measure, and although trap cropping has been used it is not very effective.

 

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          Family Buprestidae. -- The flat-headed borers have various metallic colors and very hard bodies.  Their antennae are serrate.

 

 

          The larvae feed on wood exclusively and they are easily recognized by their very much enlarged prothorax. They mine in the cambium layer and thereby girdle trees.

 

 

          The Flat-headed Apple Tree Borer overwinters in the larval stage.  Adults emerge in springtime and there is one generation per year.  Control of this beetle has deployed wrapping a tree's trunk with paper, fumigation and spraying before the beetle has had a chance to attack the trees.

 

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          Family Cantharidae. -- <Habits>; <Adults> & <Juveniles> -- The soldier beetles are powdery in appearance.  The tarsal formula is 5-5-4.  The larvae are predaceous, feeding on corn borer larvae for example.  Adults feed on flowers and pollen and thus are effective pollinators, especially on such valuable crops as alfalfa in Midwestern North America.

 

 

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Infraorder:  Bostrichiformia

 

          Family Dermestidae. -- <Habits>; <Adults> & <Juveniles> -- The carpet beetles and buffalo moths have larvae with a tapering tail and they are studded with hairs in a "fishlike manner."  They are serious pests of stored products, museum specimens, woolens, grain, feathers, etc.

 

 

          Dermestids have extreme durability and can withstand long periods of dryness and an absence of food.  They may go through "regressive molts" thereby decreasing in size.  Fumigation has been an effective control procedure.

 

          The Khapra beetle, Trogoderma granarium Everts, a native of India, is a very important economic pest where it occurs.  It dees on any stored produce.  Although it does not fly it spreads by clinging onto containers.  When it entered North America a grand scale eradication effort eradicated it.

 

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          Family Bostrichidae. Bostrichidae -- The shot-hole borers have a head that is turned down underneath the prothorax, which is enlarged.  They feed on wood products.  The lead cable borer or short-circuit borer bores into lead cables even though it does not feed on the lead.

 

 

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          Family Anobiidae. -- The drugstore beetle is similar in appearance to the Bostrichidae, but it prefers to feed on tobacco and other stored products in drugstores.  It also bears the name "death watch beetle," which is taken from the habit of making noise while boring in wood of churches during wakes, etc.

 

 

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Infraorder:  Scarabaeiformia

 

          Family Scarabaeidae. -- <Habits>; <Adults> & <Juveniles> -- The June beetles have larvae that are curved and adapted to movement in the soil.  Their head is heavily sclerotized, but their body is only lightly so, and they are often referred to as white grubs.  The antennae are lamellate.

 

 

          Adults fly at night to feed on newly developing leaves of trees thereby causing serious damage.  The larvae do serious damage to roots of crop plants.  They usually build up their numbers in sod and will attack row crops if these are planted to the site the following year.

 

          Life Cycle:  A complete cycle takes three years.  The last winter is passed as adults in cells in the ground.  Most damage is done in the second year.  There are three broods present, one being more serious than the other two.

 

          Example Species:  The Japanese Beetle, Popillia japonica Newman, was introduced into North America from Japan in 1916 on nursery plants.  It is not an important pest in Japan because of natural enemies.

 

 

          Adults feed on foliage and fruit.  They are quite attractive insects with a bright green head and thorax and brown tinged with green elytra and white spots along the abdomen sides.  There is one generation a year and overwintering is in the larval stage in soil.

 

          A soil bacterial disease has effectively controlled this beetle to some extent.  It is most prevalent in Eastern North America in areas with high annual rainfall.

 

          The Tumble Bug or Dung Beetle also bears the name of "Sacred Scarab" in Egypt.  These insects accumulate a mall of manure upon which they lay an egg.  The ancient Egyptians believed that the beetle represented the sun and the manure the earth, the rolling of the earth from sunrise to sunset being symbolic.  The 5-5-5 tarsal formula represented the 30 days of the month (15 days on each side of the beetle).  The rays on the back stood for the sun's rays.  They were in error because they believed that only males were present.  The soldiers of ancient Rome used the beetle as a symbol for their shields in battle.

 

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Infraorder:  Cucujiformia

 

     SUPERFAMILY:  Cleroidea:  All members of this group have I & II instar triangulin larvae.  They hare highly motile and shaped like Thysanura.  They have a hypermetamorphosis.

 

          Family  Trogossitidae ( = Ostomatidae).-- <Habits>; <Adults  & <Juveniles> -- Bark gnawing beetles are elongated with a head about as wide as the pronotum, and the pronotum widely separated from the base of the elytra.  They are oval or elliptical in shape with the head only half as wide as the pronotum.  They resemble the Nitidulidae somewhat.

 

 

          Many feed on other insects or on fungi under tree bark.  Some species feed on insects in grain and on the grain itself.

 

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          Family Cleridae. -- <Habits>; <Adults> & <Juveniles> -- The checkered beetles are pubescent in appearance.  Both the larvae and adults are predaceous.  They are elongated insects, 5-12 mm. long, and many have bright colors.  The pronotum is frequently narrower than the base of the elytra and sometimes narrower than the head.  The tarsi have five segments, but in many the first or the fourth segment is very small.  The antennae are usually clubbed, but sometimes serrate, pectinate or infrequently filiform.

 

 

          They occur on or within tree trunks and logs where they prey on the larvae of other wood boring insects, mainly bark beetles.  Other species occur on flowers and foliage.  Some feed on pollen.  One species is known to feed on stored meats.

 

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          Family Melyridae. (= Malachiidae) -- <Habits>;  <Adults> & <Juveniles> -- The soft-winged flower beetles are elongated, oval and soft bodied insects of 10 mm. in length.  Many species are brightly colored with brown or red and black.  Some have strange orange colored structures along the abdomen sides that may be everted and saclike or withdrawn into the body.  In some the two basal antennal segments are enlarged.

 

 

          Most adults and larvae are predaceous, with many being common flowers where they may come in contact with their prey..

 

 

     SUPERFAMILY:  Cucujoidea are flat compressed beetles with brilliant colors.  They all have long prominent antennae.  Most families are rare. 

 

          Family Cucujidae. -- <Habits>;  <Adults> & <Juveniles> -- The flat bark beetles are found under the bark of deciduous tree logs.  Some species are 13 mm. long.  Some genera have the maxillae concealed by large plates that are formed by the genae on the ventral side of the head.

 

 

          Most cucujids are predatory on mites and small insects, while others are parasitic as larvae on species of Cerambycidae and Braconidae.  They have a hypermetamorphosis.  A few species are destructive to stored grain such as the saw-toothed grain beetle, Oryzaephilus surinamensis (L.).

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          Family Coccinellidae. -- <Habits>; <Adults> & <Juveniles> -- The ladybird beetles are primarily predators of aphids both as larvae and adults.  The species are distinguished by the pattern of spots on their elytra. 

 

 

        When they are effective in biological control there must be a close relationship with the host species, otherwise introduced ladybirds will simply fly off the premises.  However the cottony-cushion scale that invaded California citrus was controlled effectively by a host-specific coccinellid, Rodolia (Novius) cardinalis (see Vedalia beetle)  Notwithstanding these scientific facts, they are often sold by plant nurseries for their unproven value as insect controls. 

 

          The Mexican bean beetle, Epilachna varivestis Mulsant, is an exception to the group in that it is very destructive to agricultural crops in some areas of North America.  Native to Mexico the beetle attacks bean crops primarily, but sometimes cowpeas and soybeans also.  After invasion from Mexico the beetle stayed in southern Arizona for about 30 years, but by 1920 it began to spread eastward.

 

          Overwintering is as an adult in protected spots.  In springtime the eggs are laid in plant foliage.  The larvae are a fuzzy yellow, and they feed for 2-5 weeks on foliage.  There are 1-5 generations per year, with most damage being caused in July and August.   Control has stressed insecticides.

 

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          Family Rhizophagidae (Rhizophaginae). -- <Habits>; <Adults> & <Juveniles> -- The root-eating beetles are small and about 1.4-3.2 mm long.  The antennae have 10 segments with a club.  The last tarsal segment is elongated.  The tip of the abdomen projects beyond the elytra.  The pygidium is exposed and the first visible abdominal sternum is about as long as sterna 2-4 combined.

 

 

          These beetles are found underneath bark or in rotting wood, with a few species living in ant nests and some in bark beetle galleries where they feed on the eggs and larvae of bark beetles.  .

 

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          Family Nitidulidae. -- <Habits>; <Adults> & <Juveniles> -- The sap beetles vary much in size, shape and habits.  Most species are 12 mm or less in length.  The antennae usually have a three-segmented club.

 

 

          Their habitat is around fermenting plant material, such as decaying fruits.  Some occur around animal carcasses.  Others are common around flowers, underneath loose bark of dead trees in humid environments.  The name "picnic beetles" has been given to them when they are annoying around such outdoor events.  One species, Carpophilus lugubris Murray, the dusky sap beetle, is a pest of sweet corn.  The larvae feed on corn kernels and can be missed during canning operations.

 

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     SUPERFAMILY:  Chrysomeloidea: 

 

          Family Chrysomelidae. -- The leaf beetles are related to the Cerambycidae with a similar tarsal structure.  They are all pests of agricultural crops and the most serious crop feeders of the Coleoptera.  However, they have much shorter antennae and are smaller than the cerambycids.  The adults feed mainly on flowers and foliage.  Some larvae feed on the surface of plant foliage, while others are leaf miners or feed on roots or bore into stems.  Overwintering is in the adult stage.  Borror et al. (1968) describe in great detail the various subfamilies of this group.

 

 

          The Colorado Potato Beetle, Leptinotarsa decemlineata (Say) is a notorious pest everywhere east of the Rocky Mountains in North America.  During World War II the United States was accused of introducing this beetle into Germany.  In 1854 it was the first economic pest of potatoes in North America although it also attacks tomato and tobacco.  It feeds on the terminal growth of plants and overwintera as an adult in the soil.  In springtime the adults feed on residual tuber shoots.  The eggs are laid in a cluster on the undersides of leaves.  There are two generations per year.

 

 

          The beetle occurred naturally on wild host plants, but preferred potatoes when these were introduced.  The first use of an arsenical insecticide, Paris Green, was used to control it.  One company sold a phony control device, which consisted simply of two boards that were to smash the beetles.

 

          Flea Beetles, Epitrix spp., cause shot-hole damage to plant foliage.  Damage is most severe on seedling plants, and only the veins of the lower leaves especially remain after feeding.  With a well developed femur on the hind legs they are quite active by hopping about on plants.

 

          The Striped or Spotted Cucumber Beetle, Diabrotica undecimpunctata howardi Barber, is a pest of squash and pumpkin.  It is necessary to plant an abundance of seed per hill to compensate for those seeds that are eaten by these beetles, although insecticidal control is often applied instead.

 

 

          Some species have been used effectively in the biological control of weeds, such as St. John's Wort or Klamath Weed (see ch-66).

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          Family Bruchidae. -- The seed beetles feed and pupate within legume seed as larvae and can attack both in the field and in storage.  They are sometimes referred to as "weevils," the various species given the common name of the crop they attack; eg., bean weevil, pea weevil.  They often contaminate dried beans and peas that have been packaged for household use.

 

 

          They are short, stout-bodied insects, most being less than 5 mm long.  The elytra are shortened and do not cover the abdominal tip.  Their body may be narrowed anteriorly and is frequently gray or brown in color.  The head is projected forward into a short broad snout.

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          Family Cerambycidae. -- The longhorn borers and round-headed borers are pests in orchard and forest plantings.  They tunnel into the trees and mine directly in the heartwood. There are many species all of which are phytophagous.  They are elongated and cylindrical with long antennae, and many species have bright colors.  The tarsi have four segments with the third segment being bilobed.

 

 

          The brightly colored species feed primarily on flowers while the more drab species are nocturnal.  The larvae bore into wood.  A few species attack living trees, but the majority prefer freshly cut logs or weakened and dying trees and are frequently wrongly blamed for a forest's destruction, which may be due mainly to environmental stress such as drought or air pollution.  Some girdle twigs. 

 

                    There is a two or three year life cycle, with adults occurring in late summer.  The Round-headed Apple Tree Borer, Saperda candida Fab., is an especially important pest in North America..  Borror et al. (1968) describe in great detail the various subfamilies of this group.

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     SUPERFAMILY:  Curculionoidea: 

 

          Family Anthribidae. -- <Habits>; <Adults> & <Juveniles> -- The fungus weevils vary considerably in size from 0.4-32 mm.  The antennae are not elbowed and some have slender antennae that extend beyond the length of the body.  The head is extended interiorly into a broad muzzle.  The elytra cover the pygidium base which is partly exposed when viewed from the side, but which is not visible from above.

 

 

          The habitat of adults is in dead twigs or underneath loose bark.  The larvae are found in woody fungi or in fungi that occur on crop plants.  Some species feed on seeds and a few bore into dead wood.  The Introduced coffee bean weevil, Araecerus fasciculatus (DeGeer) is a pest of seeds, dried fruits and berries.

 

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          Family Curculionidae. -- The weevils or snout beetles are the largest family of Coleoptera. 

 

 

          Their head is projected into a long beak with antennae thereon.  The mouthparts are located at the tip of the snout.  The lacinia and galea are still separated.

 

 

          All species are phytophagous, feeding in seeds and fruit, but the adults usually feed only on plant foliage.  Some species have larvae may that also feed on roots and twigs..  Plum and apple curculios are very important pests in North America as they tunnel into the fruit as larvae.  A characteristic C-shaped slit is cut into the fruit with the snout, and an egg is then laid therein.

 

          The Alfalfa Weevil, Hypera postica (Gyllenhal), is a serious pest of alfalfa in the Great Basin area of North America, ranking high on the pest list with the spotted alfalfa aphid.  Its origins are in the Mediterranean area and was discovered in North America in 1904.  It is most serious on alfalfa, but will also attack clover.

 

 

          The alfalfa weevil's color is dark gray with fine hairs on the thorax.  Adults begin to feed in spring and lay eggs in the stems of plants.  One female may lay 500-600 eggs.  The larvae change in color from white to green and they take the form of a curve without legs.  The pupae mature in June and July.  The generations vary with more produced in warmer climatic regions.

 

          Control has stressed early harvest and the introduction of parasitic insects.

 

          The Cotton Boll Weevil, Anthonomus grandis Boheman, is the most serious pest of cotton in North America that can damage hundreds of millions of dollars worth of cotton each year.  The larvae attack only cotton while the adults attack related plants also, such as okra and hollyhock.  This insect attacks both directly in the larval and adult stage, and there is no recovery of the plant after attack.

 

          The insect is native to North America.  It overwinters as an adult in any sheltered place.  In springtime it attacks the blossom bud by depositing a single egg per blossom.  The larvae mature in three weeks, and there are 10 generations per year.

 

          Control of boll weevil has stressed cultural methods, such as early planting and the destruction, but frequent insecticide applications have been the preferred method.

 

          White Fringed Beetles of the genus Graphognathus are serious agricultural pests in humid areas of the southern United States.  They are usually about 12 mm. long.  They were introduced into Florida around 1936 after which they spread northward.  They are general feeders on over 172 species of broad-leafed plants.  Adults cannot fly but rather cling to moving objects.  Their origin is in southern Argentina.  Reproduction is by parthenogenesis, with the female laying over 2,000 eggs in one generation per year.

 

 

          Control of white fringed beetles has stressed rotation of broad-leafed crops with grain, the treatment of soil with chemicals and mechanical barriers.

 

          The Granary Weevil, Sitophilus granarius (L.) and the Rice weevil, S. oryzae (L.) are small brownish insects that attack stored grain such as corn, rice and wheat worldwide.  Both adults and larvae feed on the grain and the larvae develop inside the grains.  The granary weevil attacks only stored grain and does not fly, while the rice weevil attacks both in the field and in stored grain, and it does fly.  The rice weevil has been considered the most important pests of grain.

 

 

          The larvae complete development only on while grain.  The female deposits one egg in one grain kernel, and the life cycle lasts about one month.  Adults can go without food for over three weeks.

 

          Control of these granary weevils has stressed tight storage containers, mechanical barriers and fumigation.  Sometimes insecticides are also used.

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          Family Scolytidae (Scolytinae). -- The engraver beetles feed in the cambium just under the bark of trees thereby causing girdling.

 

 

          Their tunnels have characteristic patterns as shown in Fig. ent64:

 

 

          Three genera, Dendroctonus, Ips and Scolytus, are of great economic importance.  Ambrosia beetles maintain fungus cultures upon which they feed.  The fungi, often called blue stain or brown stain fungi that are introduced by the adult beetles and spread by their larvae, cause the death of infested trees.  Because the adults and larvae interrupt the flow of nutrients by feeding in the plant phloem, the fungus spreads inward and clogs the water transport vessels in sapwood, which suppresses the flow of lethal pitch into the beetle galleries (Borror et al., 1968).

 

          The destructive bark beetles show a high coordination of their flying population in a synchronized mass attack, thereby overwhelming a tree's defenses by their numbers.  Both males and females respond to a combination of odors from the resin of a host tree and chemical signals from the first colonists.  Therefore, thousands of beetles can infest the same tree all at once.  There are usually one or two generations per year and overwintering is as mature larvae.

 

          Dutch Elm Disease fungus was introduced into North America in elm logs from Europe, and within 75 years spread across the continent attacking the American elm.  The European elm was desirable for its burls, which gave a good pattern to veneers used in the furniture industry.  By 2010 most American elm trees had perished The vector Scolytus multistriatus (Marsham) arrived with the logs and aided in the spread of the fungus.

 

          Control of these beetles is primarily by rogueing out dead trees, although insecticidal sprays have stopped the spread in some urban environments.

 

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      SUPERFAMILY:  Tenebrionoidea

 

          Family Anthicidae. -- <Habits>; <Adults> & <Juveniles> -- The ant-like flower beetles are small, 2-6 mm long and resemble ants.

 

 

          Their head is deflexed and constricted behind the eyes.  The pronotum of many species has an anterior hornlike process that extends over the head.  They occur on flowers and plant foliage as well as under stones and logs in debris.  A few species are found on sand dunes.

 

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          Family Meloidae. -- <Habits>; <Adults> & <Juveniles> -- The blister beetles are parasites on the eggs of grasshoppers.  They are rather narrow and elongated, and their elytra are soft and flexible.  The pronotum is narrower than either the head or the elytra.  Their name is derived from the fact that their body fluids contain cantharadin, a chemical that can cause blisters when contacting the skin.

 

 

          Some species are destructive pests of tomatoes, potatoes and other crops.  However, because the larvae of many species feed on grasshopper eggs they are considered beneficial.  Some species also live in bee nests as larvae where they feed on bee eggs and on the food stored in the cells.

 

          They have a rather complex life cycle with a hypermetamorphosis and different larval instars are very different in appearance.  The first triungulin larva usually climbs on a flower and attaches itself to a bee that visits there.  The bee then transports the triungulin to its nest where the triungulin can attack the eggs.  The second instar is similar to the triungulin but its legs are much shorter.  The third through fifth instars become thicker and scarabaeiform.  The sixth instar has a darker exoskeleton and no functional appendages.  This instar is called the coarctate larva or pseudopupa and it hibernates.  The seventh instar is small, white and active, although it also lacks legs and dos little if any feeding before pupation. (Please see Borror et al., 1968 for further details).

 

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          Family Tenebrionidae. -- <Habits>; <Adults> & <Juveniles> -- The darkling beetles or mealworms are a varied group that is recognized by the 5-5-4 tarsal formula.  The front coxal cavities are closed behind and the eyes are frequently notched.  The antennae usually have eleven segments and are either moniliform or filiform.  There are five visible abdominal sterna.  Most species are black or brown in color with a few having additional red markings on their elytra.

 

 

          Darkling beetles in drier areas occupy the habitat of the Carabidae that are abundant in more humid areas.  They may be found under stones, trash and beneath loose bark, and they are strongly attracted to light.  Most species feed on plant materials but a few are pests of stored grain.  They are easily reared as food for laboratory animals such as lizards, snakes, etc.

 

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Additional COLEOPTERA Families

 

Brentidae <Habits> <Adults> & <Juveniles>

    

Colydiidae <Habits> <Adults> & <Juveniles>

    

Dascillidae <Habits> <Adults> & <Juveniles>

    

Drilidae <Habits> <Adults> & <Juveniles>

    

Ectrephidae <Habits> <Adults> & <Juveniles>

    

Eucnemidae <Habits> <Adults> & <Juveniles>

    

Haliplidae <Habits> <Adults> & <Juveniles>

    

Helodidae <Habits> <Adults> &<Juveniles>

    

Hygrobiidae <Habits> <Adults> <Juveniles>

    

Lampyridae <Habits> <Adults> & <Juveniles>

    

Lathridiidae <Habits> <Adults> & <Juveniles>

    

Leptinidae <Habits> <Adults> & <Juveniles>

    

Lycidae <Habits> <Adults> & <Juveniles>

 

Melandryidae <Habits> <Adults> <Juveniles>

Mordellidae <Habits> <Adults> <Juveniles>

Mycetophagidae Habits Adults>  <Juveniles>

Paussidae <Habits> <Adults> <Juveniles>

Phalacridae <Habits> <Adults> <Juveniles>

Phengodidae <Habits> <Adults> <Juveniles>

Pselaphidae <Habits> <Adults> <Juveniles>

 

Pythidae (= Salpingidae) <Habits> <Adults>

                   <Juveniles>

Rhipiceridae <Habits> <Adults> <Juveniles>

Rhipiphoridae <Habits> <Adults> <Juveniles>

Rhysodidae <Habits> <Adults> <Juveniles>

Throscidae <Habits> <Adults> <Juveniles>

Trogidae <Habits> <Adults> <Juveniles>

Trogossitidae (Ostomidae) <Habits> <Adults>

                    <Juveniles>

    

Misc. Families <General Habitss>

 

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Coleoptera --Biological Control Projects (11.2% of total projects)

 

Alfalfa Weevil, Hypera postica (Gyllenhal) <ch-2.htm>

Boll Weevil, Anthonomus grandis Boheman <ch-13.htm>

Cereal Leaf Beetle, Oulema melanoplus (L.) <ch-18.htm>

Coconut Leaf-mining Beetle, Promecotheca reichei Baly <ch-28.htm>

Elm Leaf Beetle, Xanthogaleruca luteola (Müller) <ch-40.htm>

Eucalyptus Pest Insects:  Longhorn borers, Tortoise & Snout beetles <ch-41.htm>

Eucalyptus Snout Beetle, Gonipterus scutellatus Gyllenhal <ch-42.htm>

Greater European Spruce Beetle, Dendroctonus micans (Kugelann) <ch-56.htm>

Hispid Beetle, Promecotheca cumingi Baly <ch-62.htm>

Japanese Beetle, Popillia japonica Newman <ch-65.htm>

Rhinoceros Beetle, Oryctes rhinoceros (L.) <ch-93.htm>

Sugar-cane Beetle Borer (Coleoptera), Rhabdoscelus obscurus (Boisduval) <ch-102.htm>

 

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Details of Insect Taxonomic Groups

 

          Examples of beneficial species occur in almost every insect order, and considerable information on morphology and habits has been assembled.  Therefore, the principal groups of insect parasitoids and predators provide details that refer to the entire class Insecta.  These details are available at <taxnames.htm>.

 

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References      Citations

 

Introduction                                                                                                                                                                                                                                                                                         Contents