Anobiidae

Anobiid adults are 1.5-8 mm long, reddish brown to black, and covered with fine setae or pubescence. The head is usually hidden by the pronotum, and the 11-segmented antennae are inserted on the sides of the head, in front of the eyes. Full-grown larvae are about 8 mm long, grub-shaped, and yellowish white. Larval thoracic segments are enlarged dorsally, and the segments have a dorsal patch of large setae. Adults of many species are nocturnal and are rarely seen during the day. Feeding habits include infesting dry vegetable material, stored food materials, spices, and tobacco, and several species that feed on seasoned wood. The majority of anobiids feed in dry (8-12% moisture) hardwood and softwoods; their larvae are capable of digesting cellulose. Food-infesting species invade a broad range of substrates, and there are biotypes adapted to local conditions and food sources. The anobiid pests of stored food have worldwide distribution.

Furniture beetle, Anobium punctatum Adults are 2.5-6 mm long, cylindrical, and reddish brown. Elytra have punctures in longitudinal rows; the last three antennal segments are longer than the others. Exit holes are 1.6-3 mm diameter, and the frass has a gritty feel when rubbed between the fingers. Full-grown larvae are about 6 mm long, yellowish white with dark brown mandibles; there are scattered pale yellow setae on the body, and a double row of spines on the dorsum. Eggs are visible to the unaided eye and are smooth, white, and slightly ellipsoidal. Eggs are laid singly or in batches of 2-4. They are often cemented on to rough surfaces of lateral and end grain wood, in cracks, deposited into spaces between pieces ofwood, or in emergence holes, and pupation chambers from which the female emerged. Fecundity is 20-80 eggs; hatching occurs in 3-6 weeks at 65% relative humidity (RH); no eggs hatch at or below 45% RH. First-stage larva burrows into wood through the base of the egg. As it moves out of the egg the larva ingests yeast deposited on the egg by the female, and these yeasts become established within the larval gut. Yeasts are killed at 26 °C, which restricts the initial development or reinfestations of timbers in some roofs.

Larval development takes about 2 years at 22-24 °C and 70% RH, but can extend to 3-5 years. In natural habitats, such as branches of dead trees, the life cycle is completed in about 1 year. Larvae produce a network of 1-2-mm diameter galleries filled with frass and wood fragments. Pine and spruce are most susceptible to attack; there are few infestations in Douglas fir and western hemlock. Most hardwoods in temperate regions are attacked, but rarely tropical hardwoods. The outer portion of sapwood, which is usually high in nitrogen, is the preferred larval feeding site, but heartwood ofbeech, birch, and poplar may be utilized. The limited amount of nitrogen in old wood results in extensive larval galleries and slow development. Larvae feeding on Scots pine digest 26-29% of the wood eaten, and utilize 7-8% of the lignin, 40% of the cellulose and hemi-cellulose, and most of the protein in the wood. Some types of plywood have been attacked, and beetles emerged after the wood was in place. Full-grown larvae bore close to the wood surface to form a pupal chamber. Pupal stage is 3-8 weeks, and adults bite through the outer surface ofthe wood to emerge and mate.

Adult beetles live 2-4 weeks and readily fly during the warm season. Adults emergeinMay or June, butin northern latitudes they emerge in June and July. Mating males and females retreat into exitholes and crevices in the timber; males disengage from females after about 1 h and return to the wood surface. Females remain in the exit hole to lay eggs, and return to the surface to mate again. Males are attracted to a range of concentrations of the female sex pheromone, which is 2,3,5-trimethyl-6-(i-methyl-2-oxobutyl)-4H-pyran-4-one (Stegobinone). This chemical is the same as the sex pheromone for Stegobium paniceum, the drugstore beetle.

A. punctatum is widespread in North America and Europe, especially along coastal regions where ambient air humidity is high. It occurs inside buildings and outside in natural populations in dead wood. In spite of its common name, it damages structural wood rather than furniture. However, it enters houses in infested furniture and spreads to exposed, unfinished wood. Attack occurs in structural softwood or hardwood that is free of decay fungi. Temperature, humidity, and the condition of wood limit larval development. Adults produced in wood in dry environments are generally small, and less successful in mating and egg-laying. These adults produce fewer eggs and therefore decrease population viability. This combination of factors may explain why infestations decline when wood moisture levels remain low.

There are several parasites of the furniture beetle. The mite Pymotes tritici (Pymetodidae) parasitizes several species of wood-boring insect larvae, including Anobium larvae. P. tritici can bite humans, resulting in what is called woodworm bite, but it is unable to burrow into human skin. The ant-like ptero-malid wasp, Theocolaxformiciformis, is also a parasite of Anobium larvae. The adults have rudimentary wings and do not fly. The adult wasp moves through the tunnels in the wood to locate a beetle larva, or it oviposits into the larva through the wood surface.

Queensland pine beetle, Calymmaderus incisus Adults are about 3 mm long, brown and shiny. Attack in structures usually begins in the dark, subfloor areas and spreads from there to other wood members. It has not been reported from other areas, but the damage is similar to that of A. punctatum and it could have been overlooked. This beetle is distributed in Queensland, Australia where itattacks softwood timber. Infestations are predominantly in hoop pine, bunya pine, and New Zealand white pine.

Anobiid bark beetle, Ernobius mollis (Fig. 5.1a) Adults are 3.5-5.5 mm long and reddish brown. Full-grown larvae are about 7 mm long, curved and pale yellow; the head is distinct and the mandibles are dark brown. Exit hole is round and about 1.5-2 mm diameter. Eggs are laid in crevices in the bark of trees; hatching is in 10-21 days. First-stage larvae are capable of crawling on the surface of the bark for a few days before finding a route to the sapwood. Larvae feed at the interface of the bark and sapwood, and frass produced from this feeding is a mixture of brown and white particles. The brown pieces are from the bark, and yellow pieces are from the sapwood. Frass is tightly packed in galleries but is dislodged and falls free when the wood dries. Larvae pupate in an enlarged portion of their gallery and the pupal stage lasts about 10 days. Larval development is completed in 1-2 years. Adults remain in the pupal chamber for 6-12 days before biting their way to the wood surface. Emergence is during summer and extends into fall. Mating takes place within 1-2 h of emergence;

copulation lasts about 6 h. Females mate 2-3 times, and eggs are laid at night a few days after mating. Adults live about 30 days, but sometimes they overwinter.

This beetle infests softwood timber, especially wood that has small sections of bark remaining. The damage caused by E. mollis is often confused with damage caused by some bark beetles (Scolytidae). E. mollis restricts its feeding to the outer sapwood beneath the bark, and does notreinfest or cause structural damage to wood in use. This species has been introduced into the eastern USA and lives outdoors in various conifer trees. Related species, E. tenuicornis and E. granulatus, occur in eastern USA, but they do not infest wood in use.

Anobiid powderpost beetle, Euvrilletta peltata (= Xyletinus peltatus) (Fig. 5.1e) Adults are 3.4-6.3 mm long, reddish brown to black, and with fine, yellow pubescence covering the body. Eyes of male are separated by two times the width of the eye; female eyes are separated by three times the width. Antennae are 11-segmented, moderately serrate, and the last three segments are slightly enlarged. Exit holes are about 3 mm diameter; the frass from softwoods (pines, spruce, and fir) has a gritty texture when rubbed between the fingers. Full-grown larvae are about 8 mm long and yellowish white. Eggs are laid in groups of 2-3 on the surface ofwood, females prefer wood thatis 2-5 years old, and rough surfaces; fecundity is 2060 eggs, but females lay 120. Hatching is in about 8 days, and is not significantly reduced by 11-12% wood moisture or low (54%) RH. First-stage larvae bore into the wood a short distance, then turn and tunnel in the direction of the wood grain. They feed first on springwood and later in the outer sapwood; galleries are packed with fecal pellets and wood fragments. Few first-stage larvae survive in wood with moisture content below 13%, but wood moisture as low as 12% does not reduce the survival oflarvae that are 3-6 months old. Larvae cease or reduce feeding in response to low (winter) temperatures and low wood moisture content. They do the most feeding at about 24 °C; feeding is reduced or stops at 10 °C and at 32 °C. Larvae resume feeding in spring, but those not full-grown continue to feed for a year or more. Full-grown larvae tunnel close to the wood surface and prepare a pupal chamber. The pupal period is about 14 days, and adults cut the emergence holes in the wood surface. The life cycle is 1-5 years, depending on the quality of wood infested, fluctuations in temperature, and wood moisture.

Pine timber may be reinfested and infestations may continue until nearly all the sapwood portion of the infested wood piece has been consumed. Infestations rarely develop uniformly over

Stegobium Paniceum Life Cycle
Figure 5.1 Coleoptera: Anobiidae. (a) Ernobius mollis; (b) Falsogastral-lus sauteri; (c) Gastrallus immarginatus; (d) Nicobium hirtum; (e) Euvril-letta peltata; (f) Stegobium paniceum; (g) S.paniceum larva; (h) Lasioderma serricorne; (i) L. serricorne larva.

an area, because of parasites, wood properties, and the size of the initial infestation. Adult beetles begin emerging in spring and continue through mid-summer; more than 90% of the total emergence occurs within 4-6 weeks. Adults do not feed and are nocturnal. This species is distributed in eastern USA, but it has probably spread to other countries. It occurs naturally in dead branches and downed logs from northern New York to Michigan, southeastward to Florida and southwestward to Arkansas. It infests dead and seasoned parts of hardwood and softwood trees, including heartwood and sapwood. A closely related species, E. lugubris, occurs in natural habitats, and it tunnels and feeds in dead oak twigs.

Braconid parasites of E. peltata in North America include Heterospilus longicauda. The female oviposits through the outer surface of the wood on to beetle larvae feeding close to the surface; one parasite develops on each beetle larva. Beetle larvae feeding deep in the wood are usually beyond the reach of the parasite's ovipositor. After feeding on beetle larvae and becoming adults, the H. longicauda wasps make an exit hole in the wood surface, which is smaller than the powderpost beetle hole. The parasitic wasp, Theocolaxformiciformis (family Ptero-malidae) attacks larvae by burrowing through its tunnels. The adults of this parasite often exit through existing beetle emergence holes.

Decayed-wood anobiid, dampwood borer, Hadrobregmus australiensis Adults are 7-8 mm long and blackish brown. Emergence holes are round and about 3 mm diameter; pupal chambers are usually close to the wood surface and stained black inside. Frass is powdery, but because of the moisture content and wood decay in the substrate, it usually sticks together in tunnels. This beetle is limited to attacking decayed and moisture-damaged wood. It infests soft- and hardwoods, but only when conditions are conducive for wood-decay fungi. It is distributed in Australia.

Eastern death watch beetle, Hemicoelus carinatus (= Hadrobregmus) Adults are 4-6 mm long, reddish brown to dark brown, and have 10-segmented antennae. It naturally infests ash, basswood, maple, beech, and elm. Household infestations include structural beams, roof and floor joists, sills, and flooring, both new and old wood. Damage resembles that of lyctids in hardwoods, but the emergence holes of H. carinatus are larger and the frass is not a fine powder. This species is distributed primarily in eastern North America.

Western death watch beetle, Hemicoelus gibbicollis (= Hadrobregmus) Adults are 2.5-5 mm long and pale brown to brown. The dorsum of the thorax is pointed, and the antennae are 11-segmented. Full-grown larvae are about 4 mm long and pale brown to brown anteriorly. Eggs are laid singly or in batches of 3-32 in cracks or in the end grain of the wood; rarely are eggs laid in emergence holes. Fecundity is about 200 eggs; hatching occurs in about 22 days, and with 84-88% success. First-stage larvae usually crawl about 1 cm from the egg before penetrating the wood. First-stage larvae tunnel close to the wood surface, and in the direction of the wood grain. Wood moisture between 14 and 17% is optimal for larval development; larvae do not survive longer than 18 months when wood moisture is 11-12%. Larval development takes 3-6 years, and the pupal period is 15-22 days. Adults emerge from June through August, but in warm regions of its distribution (California) emergence begins earlier and extends later in the fall. Mating occurs soon after emergence and females oviposit after an inactivity period of 18-36 h. Natural infestations occur in a variety of hardwoods and softwoods, including maple, oak, western white pine, western red cedar, and redwood. This species is a pest of building timbers in coastal regions of western North America, including Washington, Oregon, and California. Douglas fir is attacked, especially in buildings that are 20 years old or older.

Cigarette beetle, Lasioderma serricorne (Fig. s.ih, i) Adults are about 3 mm long and light brown. The head and prothorax are bent downward to give a humpbacked appearance, the elytra are smooth, and the antennae are serrate. Full-grown larvae are about 4 mm long, scarabeiform, and setose. Larvae feed on seeds, nuts, beans, spices, yeast, dried insects, fish and vegetables, flour, meal, and tobacco. Eggs are laid singly in crevices in the larval food material; hatching is in 20-22 days at 20 °C and 5-6 days at 35 °C. Minimum temperature for egg hatch is about 19 °C and the maximum is about 39 °C. Low humidity inhibits hatching, but at 30 °C some eggs will hatch at 20% RH. First-stage larvae move away from light in search of food; they can enter small openings in the seams of food packages and infest a variety of material. Late-stage larvae are C-shaped and they are not able to penetrate smooth surfaces or cracks and crevices. Optimal humidity for development of the 4-6 larval stages is between 70 and 80% RH; temperature thresholds are 19 °C and 39 °C. Larvae are inactive at about 17.5 °C and enter dormancy at temperatures below this; they can remain dormant for several months at low temperatures. Larvae construct silk chambers for pupation, and they are often covered with fragments of the substrate. Pupal development is 4 days at 34 °C, 12 days at 20 °C, and it is not affected by humidity. Adults remain in the pupal chamber 4-12 days before emerging; they feed on the same food as the larvae. Development on various stored foods ranges from 106 to 135 days, and with a 2-15% survival rate. Development on wholemeal flour and peanuts ranges from 27 to 34 days, with a survival rate of 100-50%. Males live 21-43 days, and females live 18-46 days. This species is widely distributed in stored foods, and is nearly cosmopolitan.

Common book beetles, Neogastrallus librinocens, Nicobium hirtum (Fig. S.ld) Adults are about 2.4 mm long and reddish brown. Full-grown larvae are about 3 mm long and pale white. Several anobiids are associated with the habitat conditions and mold fungi that commonly occur with books and stored grain, primarily in tropical or humid environments. N. librinocens infestations occur in both old and new books, especially those in storage. Larval feeding often results in book binding being cut and pages with numerous small holes. A related species, Gastralis immarginatus (Fig. 5.1c) is also known to infest books. This species is 2.2-3 mm long and uniformly dark brown.

Broadheaded anobiid, Platybregmus canadensis Adults are 4-6 mm long and the body is reddish brown to dark brown. Antennae are 11-segmented and the last three segments are distinctly larger than preceding segments. This species attacks maple and basswood flooring and elm timbers in buildings.

Itis distributed from southern Ontario, Canada, south to New Jersey.

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