White-gutted soldiers: simplification of the digestive tube for a non-particulate diet in higher Old World termites (Isoptera: Termitidae).

Previous observations have noted that in some species of higher termites the soldier caste lacks pigmented particles in its gut and, instead, is fed worker saliva that imparts a whitish coloration to the abdomen. In order to investigate the occurrence of this trait more thoroughly, we surveyed a broad diversity of termite specimens and taxonomic descriptions from the Old World subfamilies Apicotermitinae, Cubitermitinae, Foraminitermitinae, Macrotermitinae, and Termitinae. We identified 38 genera that have this "white-gutted" soldier (WGS) trait. No termite soldiers from the New World were found to possess a WGS caste. Externally, the WGS is characterized by a uniformly pale abdomen, hyaline gut, and proportionally smaller body-to-head volume ratio compared with their "dark-gutted" soldier (DGS) counterparts found in most termitid genera. The WGS is a fully formed soldier that, unlike soldiers in other higher termite taxa, has a small, narrow, and decompartmentalized digestive tube that lacks particulate food contents. The presumed saliva-nourished WGS have various forms of simplified gut morphologies that have evolved at least six times within the higher termites.

Whole-building decontamination of Bacillus anthracis Sterne spores by methyl bromide fumigation.

AIMS: To evaluate the field inactivation of Bacillus anthracis Sterne spores with methyl bromide (MB) using commercial fumigation techniques. METHODS AND RESULTS: Eighty-seven wood and 87 glass coupons each containing ca. 1 × 10(6) B. anthracis Sterne spores, were placed in 22 locations inside a 1444 m(3) conference building. Four additional 12-coupon sets (six wood, six glass) were removed from the building at 16, 24, 32 and 40 h during fumigation. The building was sealed under two tarpaulins and fumigated with MB at ≥225 g m(-3) mean concentration for 48 h at 28°C and 83% RH. All B. anthracis spores fumigated for more than 16 h were inactivated. A single wood coupon from the 16-h set yielded ca. 2 × 10(3)  CFU. No damage to the building or its contents was observed. CONCLUSIONS: MB fumigation is a rapid, economical and effective whole-structure decontamination method for B. anthracis spores. SIGNIFICANCE AND IMPACT OF THE STUDY: MB fumigation offers a method of whole-structure B. anthracis decontamination without removal of materials, damage to sensitive electronics, costly indoor retrofitting.

Attraction of alates of Cryptotermes brevis (Isoptera: Kalotermitidae) to different light wavelengths in South Florida and the Azores.

The termite Cryptotermes brevis (Walker) (Isoptera: Kalotermitidae) is an urban pest that causes much damage to wood structures. Little has been done concerning the use of control methods for alates. C. brevis is known to have phototropic behavior during the dispersal flights, and this knowledge has been applied for preventative control in the Azores where this species is a serious urban pest. We were interested in determining whether there was a light wavelength preference by the alates of C. brevis to optimize light traps against this species. Six light wavelengths were tested: 395 nm (UV), 460-555 nm (white), 470 nm (blue), 525 nm (green), 590 nm (yellow), and 625 nm (red) in choice chambers, with dark chambers as controls. Two populations were tested, one population in Florida and one population in the Azores (Terceira Island). We found consistent results for both populations, with a preference for the light wavelengths in the white, blue, and green spectrum (460-550 nm). This information can be used to build more effective light traps that can be used by home owners in the Azores to help control this pest.

Chemical prevention of colony foundation by Cryptotermes brevis (Isoptera: Kalotermitidae) in attic modules.

Disodium octaborate tetrahydrate (DOT) dust, DOT aqueous solution, imidacloprid dust, and amorphous silica gel dust with synergized 1% pyrethrins were applied on wood surfaces to simulated attic modules. Modules (30 by 30 cm) with and without fiberglass insulation were exposed to dispersal flights of Cryptotermes brevis (Walker) in May and June of 1998 and 1999. Six months after flights, modules were disassembled and inspected for nuptial chamber location and contents. During both years, air and water control treatments contained 22.2+/-9.94 (mean +/- SD) nuptial chambers, 7.5+/-5.7 live imagos, and 2.0+/-1.4 chambers with brood. This survivorship indicated that the attic modules performed well as a colonizing platform for C. brevis. C. brevis dealates preferred constructing nuptial chambers in the crevices at the bases or tops of the modules instead of internal crevices. Modules treated in 1998 and 1999 with DOT or silica dusts contained no live termites, whereas zero of five modules treated with imidacloprid dust in 1998 and two of 20 modules treated with imidacloprid dust in 1999 contained single live incipient colonies. In 1998, 15% DOT solution, applied as a postconstruction treatment, yielded significantly fewer chambers and live termites than controls, but was not as effective as dusts in preventing successful colonization. In 1999, the DOT solution, applied as a construction-phase treatment, was equally as effective in preventing colonization as the dust treatments during that year. Results indicate that dust formulations of DOT, silica gel, and imidacloprid can be used to prevent drywood termite colonization in existing building voids and attics. Where the entire wood framing is exposed to treatment, such as during building construction, aqueous DOT solution can be equally effective as dusts in preventing colonization by C. brevis.

Transfer of toxicants from exposed nymphs of the drywood termite Incisitermes snyderi (Isoptera: Kalotermitidae) to unexposed nestmates.

Two formulations of spinosad (NAF-85 and NAF-371) were evaluated to determine the effect of concentration, deposit condition (dried, wet, or topical), and exposure time (0.1-10 h) for toxicant transfer among nestmates in the drywood termite Incisitermes snyderi (Light). Spinosad treatments were compared with two formulations of disodium octaborate tetrahydrate (DOT) (10% aqueous dilution, 98% dust) and with 35% calcium arsenate dust. Termites were dyed and individually exposed to different treatments for 0.1, 1.5,1.0, 5.0, 10.0 h, or 0.1 and 1.0 h (DOT and calcium arsenate dust) and then placed with 10 unmarked, untreated nestmates in a petri dish. Spinosad formulations also were evaluated by topical application to dyed termites. Transfer of lethal doses of toxicants between termites was indicated by significant mortality of untreated termites in 25 of 28 treatments by 28 d after introduction of dyed, treated termites. Only three treatments, one spinosad treatment (NAF-371, wet, 1 h) and both DOT 10% solution treatments, resulted in mortality of untreated termites that was not significantly different than that of water-treated controls. Two spinosad treatments and both calcium arsenate dust treatments resulted in >90% (94-98%) mortality of untreated termites by 28 d after introduction. Mortality of untreated termites was significantly different from controls for the two spinosad formulations, depending on condition of deposit and duration of dyed termite exposure to treatments.

Control of Coptotermes havilandi (Isoptera: Rhinotermitidae) with hexaflumuron baits and a sensor incorporated into a monitoring and baiting program.

A sensor consisting of a wooden monitor painted with a conductive circuit of silver particle emulsion was placed in a monitoring station to detect feeding activity of the subterranean termite Coptotermes havilandi Holmgren. Sensor accuracy was 100% 1 mo after installation, but 9 mo after sensor placement, the rate declined to 73%. After the detection of C. havilandi in the stations, baits containing the chitin synthesis inhibitor hexaflumuron were applied in five colonies, and four colonies were eliminated within 3-5 mo. Baiting could not be completed for the remaining one colony because the site became inaccessible.

Laboratory and field evidence for maleproduced aggregation pheromone inRhynchophorus cruentatus (F.) (Coleoptera: Curculionidae).

Laboratory and field assays were conducted to determine if palmetto weevil,Rhynchophorus cruentatus (F.), adults produce an aggregation pheromone. Attraction of females in a Y-tube olfactometer to conspecific males was greater than to clean air. Male and female attraction to conspecific male volatiles combined with host-palm,Sabal palmetto (Walter), volatiles was greater than to host-palm volatiles alone. Similarly, more weevils were caught in the field in traps baited with conspecific males plus host-palm tissue than in similar traps baited with only males, or palm tissue, or females, or females plus palm tissue. These results suggest thatR. cruentatus males produce an aggregation pheromone(s) that is highly attractive to conspecific adults of both sexes when combined with host-palm volatiles. This study is an important step towards understanding the chemical ecology ofR. cruentatus.

Allelochemical resistance of bald cypress,Taxodium distichum, heartwood to the subterranean termite,Coptotermes formosanus.

The heartwood of bald cypress,Taxodium distichum (L.) Rich., resisted feeding attack by the Formosan subterranean termite,Coptotermes formosanus Shiraki. Hexane-extracted heartwood, however, was consumed at > 12 times the amount of sound heartwood eaten. A bioassay usingT. distichum sapwood as a feeding substrate was employed to assess the antitermitic activity of successive hexane, acetone, and methanol extracts of heartwood shavings and isolates derived from the active hexane extract. Two fractions, eluted from the crude hexane extract by liquid chromatography, significantly reduced termite feeding compared to the parent extract, while a third fraction was less active than the original hexane extract. Each fraction contained one major component. All three components were structurally related diterpenes. The two most active heartwood constituents were identified by GC-MS and NMR as ferruginol and manool, while the third and least active, but most prevalent, compound in heartwood was identified as nezukol. Results of bioassays suggest that these allelochemicals act principally as feeding deterrents with accompanying termite mortality due to starvation.

Identification of the defensive secretion from soldiers of the North American termite,Amitermes wheeleri (Desneux) (Isoptera: Termitidae).

Head capsule extracts ofAmitermes wheeleri soldiers yielded an isomeric mixture (67 µg/ soldier) of three sesquiterpene hydrocarbons identified by EIMS, [(13)C]-, and [(1)H]NMR as (+)-(S,Z)-α-bisabolene (53%), (+)-(R)-ß-bisabolene (16%), and (-)-(Z)-α2-bisabolene (31%). When alarmed, the termite soldiers secreted the fluid onto the head surface surrounding the efferent pore of the frontal gland reservoir. A defensive function for the soldier secretion was indicated by the avoidance behavior displayed toward alarmed soldiers by the antagonistic ants,Pogonomyrmex rugosus andIridomyrmex humilis. Laboratory studies demonstrated that the sesquiterpene mixture is repellent to foragingI. humilis workers.

Drywood termite feeding deterrents in sugar pine and antitermitic activity of related compounds.

The feeding deterrent activity of sapwood extracts of sugar pine,Pinus lambertiana Dougl., and related compounds was determined against immatures of the western drywood termite,Incisitermes minor (Hagen). A bioassay was designed to quantify reductions in termite feeding caused by deterrent chemicals. Crude extracts and isolated fractions of sugar pine were deterrent and not preferred byI. minor at 0.5 mg/cm(2). Fatty acids occurring in sugar pine extracts had a broad range of deterrent activity. Long-chain saturated fatty acids were deterrent at 0.25 and 0.05 mg/cm(2). Unsaturated or intermediate length (C8-C14) acids, many not found in sugar pine wood, were less active than long-chain saturated acids. Related alpha-halogenated compounds were highly deterrent at 0.05 mg/cm(2) regardless of chain length or presence of a carboxylic acid moiety. Deposits of 2-iodooctadecanoic acid reduced termite feeding at 5 µg/cm(2), while 2-bromooctadecanoic acid had deterrent activity comparable to commercial wood preservatives. None of the halogenated compounds tested were termiticidal.