Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

Testing the “new associations” biological control concept with a tachinid parasitoid (Euclytia flava)

Males of the spined soldier bug,Podisus maculiventris (Heteroptera: Pentatomidae), produce an attractant pheromone that is exploited as a host-finding kairomone by a complex of parasitic species. The capability to catch hundreds of a generalist tachinid fly parasitoid,Euclytia flava, alive in traps baited with the pheromone ofP. maculiventris provided an opportunity to test the premise of the new associations biological control concept. The hypothesis that host species newly associated with a parasitoid are maladapted relative to native-native associations was tested by givingE. flava females a choice between native and exotic stink bugs (Heteroptera: Pentatomidae). WildE. flava females preferred to oviposit on exotic pentatomid species rather than indigenous, known host species, both in field traps baited with the pheromone of a native host and in the laboratory. Data presented here demonstrate that an invader may be vulnerable to native parasitoids in one aspect of the parasitism process (acceptance), yet go unrecognized as a potential host.     

Male-Released Sex Pheromone of the Stink Bug Piezodorus hybneri

Male-released semiochemicals of the stink bug Piezodorus hybneri (Heteroptera: Pentatomidae) elicit attraction of male and female bugs and homosexual behavior in males. Three active components were isolated from the airborne volatiles of males by flash chromatography, with the activity monitored by GC-EAD and behavioral bioassay. The pheromone system was characterized as a mixture of -sesquiphellandrene, (R)-15-hexadecanolide, and methyl 8-(Z)-hexadecenoate (ratio: 10:4:1), and the activity of the semiochemicals was assessed with authentic samples. Enantiomerically pure samples of the R and S macrolactones were obtained by Yamaguchi's and Mitsunobu's macrolactonization of a key intermediate, (R)-15-hydroxyhexadecanoic acid. The nonnatural S stereoisomer was neither a beneficial nor a behavioral antagonist. Individual constituents or binary mixtures were active, but the optimal male response was elicited only by the full mixture. Behavioral observation and the fact that the onset of pheromone production is coincident with ovarian development strongly suggest that these semiochemicals are, in fact, sex pheromones.     

Semiochemicals from the Predatory Stink Bug Eocanthecona furcellata (Wolff): Components of Metathoracic Gland, Dorsal Abdominal Gland, and Sternal Gland Secretions

Volatile compounds from the metathoracic glands (MTG), dorsal abdominal glands (DAG), and sternal setae of the generalist predatory stink bug Eocanthecona furcellata (Wolff) were studied by gas chromatography–mass spectrometry. MTGs of both male and female bugs contained (E)-2-decenal as the major component, with lesser amounts of (E,E)-2,4-decadienal, (E,Z)-2,4-decadienal, and (E)-2,9-decadienal. The relative amount of (E)-2,9-decadienal in the MTGs of female bugs was higher than in male bugs. There was no dimorphism in the morphology of the DAGs of adults. However, the DAG contents of adult bugs were different between the sexes. Geraniol was found only in the DAGs of males, and limonene and -terpineol were found only in the DAGs of females, whereas linalool oxide isomers, linalool, neral, and geranial were found in DAGs of both sexes. The DAG contents of nymphs were also analyzed, with 4-oxo-(E)-2-hexenal, 4-oxo-(E)-2-octenal, tridecane, and tetradecanal being major components. Male bugs but not females possess sternal setae, and 6,10,13-trimethyltetradecyl isovalerate was detected from extracts of the sternal setae of males. The possible biological significance of dimorphism in the contents of the glands in adults is discussed.     

Sex pheromone of oriental beetle,Exomala orientalis: Identification and field evaluation

A gas chromatograph coupled with a behavioral bioassay was used to identify two sex pheromone components, 7-(Z)- and 7-(E)-tetradecen-2-one of the Oriental beetle (OB),Exomala orientalis. Field experiments showed that the blend of the two isomers (Z:E, 7:1) was not significantly more attractive than theZ component alone. The best performance of traps baited with the synthetic sex pheromone was achieved when they were set with the pheromone device at 30 cm above the ground. Catches in traps baited with 1 and 10 mg were not significantly different, but they were higher (2.9-fold) than captures in traps loaded with 0.1 mg of the pheromone. Further investigations by GC-EAD revealed the presence of a possible minor component, but the small amount of material prevented its identification. 2-(E)-Nonenol, with the same retention time as the natural product, did not affect the attractancy of the synthetic sex pheromone. GC-EAD screening of previously identified sex pheromones of scarab beetles showed that male antennae of the Oriental beetle responded to japonilure, but it showed neither synergism nor inhibition to the OB sex pheromone.     

(7<Emphasis Type="Italic">Z</Emphasis>,9<Emphasis Type="Italic">E</Emphasis>)-2-Methyl-7,9-Octadecadiene: A Sex Pheromone Component of <Emphasis Type="Italic">Lymantria Bantaizana</Emphasis>

Our objective was to identify the sex pheromone of Lymantria bantaizana (Lepidoptera: Lymantriidae) whose larvae feed exclusively on walnut, Juglans spp., in China, and Japan. Coupled gas chromatographic–electroantennographic detection (GC-EAD) analyses of pheromone gland extracts revealed a single EAD-active component. Retention index calculations of this compound on four GC columns suggested that it was a methyl-branched octadecadiene with conjugated double bonds. In GC-EAD analyses of 2-methyloctadecenes, (Z)-2-methyl-7-octadecene and (E)-2-methyl-7-octadecene elicited the strongest antennal responses, suggesting that the double bond positions were at C7 and C9. In comparative GC-EAD analyses of pheromone gland extract and stereoselectively synthesized isomers (E,E; E,Z; Z,E; Z,Z) of 2-methyl-7,9-octadecadiene, the (E,Z)- and (Z,E)-isomer had retention times identical to that of the candidate pheromone, but only the latter isomer elicited strong EAD activity. Results of field experiments in Japan substantiated that (7Z,9E)-2-methyl-7,9-octadecadiene is the L. bantaizana sex pheromone, a compound previously unknown in the Lepidoptera. Detection surveys in North America for exotic Eurasian forest defoliators could include traps baited with the L. bantaizana pheromone.     

Volatile compounds from the predatory insectPodisus maculiventris (Hemiptera: Pentatomidae)

In the predatory spined soldier bug,Podisus maculiventris, the dorsal abdominal glands are much smaller in adult females than males. Females produce a mixture of (E)-2-hexenal, (E)-2-octenal, (E)-2-hexenoic acid, benzaldehyde, and nonanal in these glands. The female dorsal abdominal gland secretion may be a close-range pheromone since the dorsal abdominal gland secretion from males has been shown to be a long-range aggregation pheromone in this species. The metathoracic scent gland secretions of male and female spined soldier bugs are apparently identical, and similar to that of other pentatomids, except for the presence of the monoterpene alcohol, linalool.Mention of a commercial product does not constitute an endorsement of this product by the USDA.     

Sex attractant pheromone of the red-shouldered stink bug Thyanta pallidovirens: a pheromone blend with multiple redundant components

The male-produced sex pheromone of the red-shouldered stink bug, Thyanta pallidovirens (Stål) (Hemiptera: Pentatomidae) consists of a blend of methyl (E2,Z4,Z6)-decatrienoate (E2,Z4,Z6–10:COOMe), and the sesquiterpenes (+)-curcumene, (–)-zingiberene, and (–) --sesquiphellandrene. In laboratory bioassays, sexually mature males attracted sexually mature females but not males, and females did not attract either sex. Extracts of volatiles collected from sexually mature males contained compounds not present in extracts from females or sexually immature males, and male-produced extract was attractive to females. Biological activity was lost when the extract was fractionated, indicating that the pheromone consisted of at least two components having different chemical properties. Individually, pheromone components were not attractive to females, but E2,Z4,Z6–10:COOMe in combination with at least one of the three male-produced sesquiterpenes was attractive. The presence of more than one sesquiterpene in the blend did not increase attraction, indicating redundancy in the pheromone signal. Male extract was as attractive as a blend reconstructed from synthesized compounds, indicating all biologically active components had been identified. In bioassays conducted at dusk in a 1- × 1- × 1-m screen field cage, females were attracted to synthetic pheromone lures. In field trials, adult female T. pallidovirens were attracted to pheromone-baited traps in relatively low numbers. The profile of volatiles released by sexually mature males of a congeneric species, Thyanta accerra custator McAtee, was remarkably similar to that of male T. pallidovirens, with the exception that the former species produced (E)-2-decenal, a compound that was not found in T. pallidovirens extracts.     

Interspecific Pheromone Cross-Attraction Among Soybean Bugs (Heteroptera): Does Piezodorus hybneri (Pentatomidae) Utilize the Pheromone of Riptortus clavatus (Alydidae) as a Kairomone?

The chemical and ecological function of cross-attraction of Piezodorus hybneri (Pentatomidae) to the Riptortus clavatus (Alydidae) pheromone (a mixture of three components) was studied. In a field attraction test using traps with synthetic pheromone components, P. hybneri was attracted to (E)-2-hexenyl (E)-2-hexenoate, a component of the R. clavatus pheromone. Other components had neither an additive nor a synergistic effect on the attraction of P. hybneri. Neither (E)-2-hexenyl (E)-2-hexenoate nor other components of the R. clavatus pheromone were detected in volatiles or whole-body extracts of P. hybneri adults by gas chromatographic analysis. In addition, (E)-2-hexenyl (E)-2-hexenoate could not be found in volatiles of soybean plants. Therefore, it appears that P. hybneri responds to a component of the R. clavatus pheromone that is not emitted by P. hybneri itself. We discuss this interspecific pheromone cross-attraction of the soybean bug and hypothesize that P. hybneri utilizes the pheromone of its competitor as a kairomone for host location.     

Field attraction ofBiprorulus bibax Breddin (Hemiptera: Pentatomidae) to synthetic aggregation pheromone and (E)-2-hexenal,a pentatomid defense chemical

A synthetic blend of the aggregation pheromone [(3R,4S,1E)-3,4-bis(1-butenyl)tetrahydro-2-furanol, linalool, farnesol, and nerolidol] of the spined citrus bug,Biprorulus bibax, and the pentatomid defense chemical, (E)-2-hexenal, both attracted adultB. bibax to individual trees in citrus orchards. Lemon trees containing single glass vials with aggregation pheromone or (E)-2-hexenal were colonized by significantly greater numbers of reproductiveB. bibax than unbaited trees. There was no significant difference between the treatments and bug recruitment was not improved by using both treatments.B. bibax did not enter cylinder/funnel traps baited with aggregation pheromone but colonized trees containing the traps. Orange or lemon trees containing aggregation pheromone on orchard perimeters recruited significantly larger populations of emigrating, nonreproductiveB. bibax during fall than untreated trees. Nonreproductive bugs were not attracted to trees containing (E)-2-hexenal. The potential for using these semiochemicals as management tools forB. bibax is discussed.     

Pheromones of milkweed bugs (Heteroptera: Lygaeidae) attract wayward plant bugs: Phytocoris mirid sex pheromone

The synthetic aggregation pheromone of the large milkweed bug, Oncopeltus fasciatus (Dallas) (Lygaeinae), also attracted males of the plant bug, Phytocoris difficilis Knight (Miridae). Field testing partial blends against the six-component blend comprising the Oncopeltus pheromone showed that cross-attraction of P. difficilis males was due to synergism between (E)-2-octenyl acetate and (E,E)-2,4-hexadienyl acetate. Hexyl acetate was abundant in the metathoracic scent gland (MSG) secretion of P. difficilis males, but because female P. difficilis could not initially be found in the field, further combinatorial tests were guided by prior research on the pheromones of two Phytocoris species in the western United States. The combination of hexyl, (E)-2-hexenyl, and (E)-2-octenyl acetates was as attractive to P. difficilis males as the milkweed bug pheromone, yet no milkweed bugs were drawn to this blend. Gas chromatographic (GC)-electroantennographic detection (EAD) and GC-mass spectrometric (MS) analyses of female P. difficilis MSGs determined that their secretion contained predominantly hexyl, (E)-2-hexenyl, and (E)-2-octenyl acetates (all strongly EAD-active)—the latter two compounds found only in trace amounts from males—plus five minor female-specific compounds, three of which were EAD-active. (E,E)-2,4-Hexadienyl acetate was not detected from P. difficilis females or males. The blend of the three major components, hexyl, (E)-2-hexenyl, and (E)-2-octenyl acetates (2:1.5:1 by volume), was as attractive as the blend of all six EAD-active compounds identified from females, indicating that this ternary blend constitutes the sex pheromone of P. difficilis. Hexyl acetate with (E)-2-octenyl acetate also attracted males of another species, P. breviusculus Reuter, but addition of (E)-2-hexenyl acetate and/or (E,E)-2,4-hexadienyl acetate inhibited attraction of P. breviusculus males. Attraction of P. difficilis males occurred mainly during the first half of scotophase. The possible neurophysiological basis for this asymmetrical cross-attraction is discussed.     

Semiochemical Investigations of the Insidious Flower Bug, <Emphasis Type="Italic">Orius insidiosus</Emphasis> (Say)

Females of the insidious flower bug, Orius insidiosus (Say) (Hemiptera: Heteroptera: Anthocoridae), produce a volatile sex pheromone and a non-volatile trail pheromone. The sex pheromone consists of the female-specific compound, (E)-2,7-octadienal, and a compound emitted by both sexes, (E)-2-octenal. A synthetic blend of octadienal and octenal weakly, but significantly, attracted O. insidiosus males to sticky traps in the field. The trail pheromone is somehow deposited by O. insidiosus females on the substrate as they walk, and, once contacted, stimulates conspecific adults to search in the vicinity. O. insidiosus males most likely respond to the trail pheromone as the ultimate means to locate potential mates, whereas the benefit of females responding to the trail pheromone may be that this signal acts as a cue indicating the likelihood of finding nearby prey. The O. insidiosus trail pheromone compounds were not identified. The volatile and non-volatile pheromones of O. insidiosus, along with prior research demonstrating that Orius and other anthocorids frequently exploit prey-associated odors as kairomones that guide their foraging, highlight the extent to which the minute pirate bugs use chemical communication. The semiochemistry of the Anthocoridae, particularly their reliance on non-volatile pheromones and kairomones, reinforces the emerging realization that other terrestrial heteropterans also substantially communicate via contact chemoreception, although this communicative channel has not been thoroughly investigated. Mention of commercial products does not constitute an endorsement by USDA.     

Disruption of Secondary Attraction of the Spruce Beetle, Dendroctonus rufipennis, by Pheromones of Two Sympatric Species

Capture of spruce beetles, Dendroctonus rufipennis, in multiple-funnel traps baited with frontalin and -pinene was reduced by up to 42% in the presence of synthetic (+)-exo- and (+)-endo-brevicomin, aggregation pheromones of the sympatric species Dryocoeles affaber. (±)-endo-Brevicomin was inhibitory to spruce beetles in two experiments and (±)-exo-brevicomin was inhibitory in one experiment, reducing spruce beetle trap catches by up to 87% and 75%, respectively. Spruce beetle trap catches were also reduced by 85% by (±)- or (+)-ipsdienol, but not by (–)-ipsdienol. Ips tridens, a second sympatric species, produces both enantiomers of ipsdienol in its pheromone blend. Responses by D. affaber to its own pheromone were significantly enhanced by addition of the spruce beetle lure. Enantiospecific pheromones of secondary competing species, or less costly racemic substitutes, may be useful for managing spruce beetles using competitive displacement or exclusion. Baiting susceptible hosts with pheromones of secondary species may enhance attack by secondary species, while partially repelling spruce beetles.     

Multifunctional communication inRiptortus clavatus (Heteroptera: Alydidae): Conspecific nymphs and egg parasitoidOoencyrtus nezarae use the same adult attractant pheromone as chemical cue

The bean bug,Riptortus clavatus lays scattered eggs (as opposed to the egg masses of pentatomids) on host as well as nonhost plants. Therefore, the first feeding stage (second-instar) nymphs emerging from eggs laid on nonhost plants need a signal that enables them to locate a food source at the lowest energy cost. Male-released (E)-2-hexenyl (E)-2-hexenoate, (E)-2-hexenyl (Z)-3-hexenoate, and myristyl isobutyrate play the double role of attractant pheromone for adults as well as aggregation pheromone, which enables the second-instar nymphs to find the host food plant. These male-specific semiochemicals are released only when foodstuff is available. On the other hand, females ofOoencyrtus nezarae, the most effective parasitoid of the host in Kumamoto, Japan (where the field experiments were conducted), utilize these semiochemicals as kairomones in order to locate the potential host community. Field experiments revealed that the synthetic pheromone rivaled 10 live males in the attraction of adults and second-instar nymphs. Captures of the egg parasitoidO. nezarae females in cylindrical sticky traps were significantly higher in traps baited with the synthetic semiochemicals than in control traps. The number of females captured was significantly higher than the number of males, although the captures in the sticky suction trap system revealed that the populations of male and female were not significantly different.     

Identification and synthesis of a male-produced sex pheromone from the stink bug Chlorochroa sayi

The reproductive behavior of the stink bug Chlorochroa sayiwas studied in the laboratory. There was a sexual maturation period of about 10 days before bugs began mating. Sexually mature adult bugs engaged in courtship consisting of antennation and head-butting of the female by the male, before the female adopted a receptive posture and copulation occurred. Both sexes mated multiple times during their life-spans, with the mean duration of copulations of virgin bugs (42.3 ± 19.6 min) and experienced bugs (37.3 ± 28.4 min) being similar. Most matings were initiated in the late afternoon or evening, when pheromone production by males was greatest. Males transferred sperm and nutrients constituting about 17% of their body weight to females during mating. Three male-specific components, methyl geranate, methyl citronellate, and methyl (E)-6-2,3-dihydrofarnesoate in a ratio of 100 : 0.45 : 1.6, were first detected in volatiles collected from male bugs on green beans about 9–12 days after the final molt to the adult stage. In vertical Y-tube bioassays, females were attracted to odors from mature male bugs, and to a blend of the three male-produced components. Low numbers of females also were attracted in field trials with the three-component blend. The relatively weak attraction may be a result of other, as yet unknown cues being required in addition to the pheromone, such as visual or substrate-borne vibrational cues.     

Response of The Lacewing Chrysopa cognata to Pheromones of its Aphid Prey

The lacewing Chrysopa cognata, one of the principal predators of aphids in Korea, was tested for responses to the aphid sex pheromone components (4aS,7S,7aR)-nepetalactone and (1R,4aS,7S,7aR)-nepetalactol and the aphid alarm pheromone (E)--farnesene. Electroantennogram responses were obtained to the sex pheromone components but not to (E)--farnesene. The sex pheromone components were attractive in a Y-tube olfactometer assay and in field trials with water traps, but no attraction was observed to (E)--farnesene.     

Sex pheromone components of three species ofSemiothisa (Geometridae), (Z,Z,Z)-3,6,9-heptadecatriene and two monoepoxydiene analogs

Adult males ofSemiothisa signaria dispuncta (Walker) were attracted to field traps baited with (Z,Z,Z)-3,6,9-octadecatriene and (Z,Z)-6,9-cis-3,4-epoxy-octadecadiene. However, analyses of sex pheromone gland extracts of females of this species by GC-MS and by GC in combination with an electroantennograph detector (GC-EAD) showed the pheromone to be comprised of a mixture of the next lower homologs: (Z,Z,Z)-3,6,9-heptadecatriene and (Z,Z)-6,9-cis-3,4-epoxy-heptadecadiene. Blends of these two C₁₇ compounds were subsequently found to be more attractive to males in the field than the corresponding C₁₈ mixtures. Sex pheromones of two otherSemiothisa species were also found to contain C₁₇ components. (Z,Z,Z)-3,6,9-Heptadecatriene, detected by GC-EAD analysis of a female abdominal tip extract ofS. bicolorata (Fabricius), attracted conspecific males, and this attraction was significantly reduced by additions of (Z,Z)-6,9-cis-3,4-epoxyheptadecadiene, the major pheromone component ofS. signaria dispuncta, to the lure. (Z,Z)-3,9-cis-6,7-Epoxy-heptadecadiene was detected by GC-EAD analysis as the primary male antennal stimulatory component present in abdominal tip extracts ofS. ulsterata (Pearsall), and males of this species were attracted to traps baited with this epoxide. Each of these three C₁₇ compounds constitute previously unknown lepidopteran sex pheromone components. Blends of (Z,Z, Z)-3,6,9-heptadecatriene and (Z,Z)-3,9-cis-6,7-epoxyheptadecadiene attracted males of a fourth species,S. delectata Hulst, but no females of this species were obtained to permit analysis of its sex pheromone. The occurrence of (Z,Z,Z)-3,6,9-heptadecatriene inS. neptaria (Guenee) females was indicated by GC-MS analysis of an abdominal tip extract; however, no males were attracted to any of the fielded mixtures containing this hydrocarbon.     

(E)-11,13-tetradecadienal: Major sex pheromone component of the eastern blackheaded budworm,Acleris variana (Fern.) (Lepidoptera: Tortricidae)

(E)-11,13-Tetradecadienal (E11,13–14:Ald) is the major sex pheromone component of the eastern blackheaded budworm (EBB),Acleris variana (Fern.). The compound was identified in female pheromone gland extracts by coupled gas chromatographic-electroantennographic detection (GC-EAD), coupled GC-mass spectrometry in selected ion monitoring mode, and retention index calculations of candidate pheromone components.E11,13–14:Ald alone as trap bait was very attractive to male EBB. Addition of the corresponding diene alcohol or acetate or both did not enhance attraction. (Z)-11,13-Tetradecadienal in binary combination with (E)-11,13–14:Ald neither enhanced nor reduced trap catches. Increasing the amounts of pheromone from 0.01 to 10 µg increased trap catches, but increase of pheromone quantity above 100 µg proportionately reduced attraction. Stabilization of slowly polymerizingE11,13–14:Ald and development of a sustained, adequate release rate is required for pheromone-based monitoring of EBB populations.     

Phloeophagous and predaceous insects responding to synthetic pheromones of bark beetles inhabiting white spruce stands in the Great Lakes region

Tree killing and saprophytic bark beetles exert important ecological and economic roles in North American spruce forests. Chemical signaling among bark beetles, and responses by associate insects such as predators and competitors, have significant effects on the population dynamics and ecology of this community. Synthetic pheromones of primary (tree killing) and secondary (saprophytic) bark beetle species and blank controls were tested using multiple funnel and lower stem flight traps in white spruce forests in Wisconsin, Michigan, and Minnesota. Six phloeophagous and four predaceous species were collected with significant attraction by the bark beetles Dryocoetes affaber, Dryocoetes autographus, and Polygraphus rufipennis, and the predatory checkered beetles (Coleoptera: Cleridae) Thanasimus dubius and Enoclerus nigrifrons. In general, trap catches to synthetic lures resembled the species composition obtained by felling trees and collecting emerging beetles in a companion study, although several species showed differing trends. Some cross attraction occurred among bark beetles and between bark beetles and predatory beetles. For example, P. rufipennis was abundant in traps baited with Dryocoetes spp. pheromones. Thanasimus dubius and E. nigrifrons were collected in significant numbers in traps baited with the pheromone of the spruce beetle (Dendroctonus rufipennis), frontalin plus -pinene. This is a new observation for E. nigrifrons. Attraction of T. dubius to the pheromones of at least three bark beetle species in the Great Lakes region, as well as to several southern and western species, reflects its role as a habitat specialist and feeding generalist. Several other important predators and competitors commonly obtained in pine forests in this region were not obtained in these spruce stands, either in response to synthetic pheromones of spruce colonizing beetles, or in host material colonized by these beetles. Potential differences in predator prey dynamics between spruce and pine ecosystems in the Great Lakes region are discussed.     

Attraction ofCarpophilus spp. (Coleoptera: Nitidulidae) to synthetic aggregation pheromones and host-related coattractants in Australian stone fruit orchards: Beetle phenology and pheromone dose studies

Synthetic aggregation pheromones ofCarpophilus hemipterus (L.) andCarpophilus mutilatus Erichson were field tested during a 10-month period in southern New South Wales stone fruit orchards to determineCarpophilus spp. phenology and the effect of two pheromone doses on attraction. Aggregation pheromones synergize the attraction of host volatiles toCarpophilus spp. Four major species,C. hemipterus, C. mutilatus, C. davidsoni Dobson andC. (Urophorus) humeralis (F.), were trapped, with greater numbers of each species inC. hemipterus pheromone/fermenting whole-wheat breaddough-baited traps, than in dough-only-traps. InC. mutilatus pheromone/ fermenting-dough-baited traps, onlyC. mutilatus andC. davidsoni responded in greater numbers than to dough-only traps. Beetles first appeared in traps in late September (early spring) when daily maximum temperatures averaged 17.5C. Trappings reached a peak during October and declined to very low levels in November–December (late spring-early summer). Numbers trapped of all species increased during February–March (late summer–early autumn), presumably due to the presence of abundant host resources (ripening and fallen fruit), and continued at high levels until May (late autumn). An 18-week study demonstrated significantly greater responses byCarpophilus spp. to 5000-g than to 500-g doses of C.hemipterus andC. mutilatus pheromones. Greatest responses to 5000g were recorded forC. hemipterus andC. mutilatus responding to their own pheromones (increased attraction over dough alone of 259x and 21.2x respectively). Implications of the study and the potential for using synthetic aggregation pheromones for managingCarpophilus spp. populations in Australian stone fruit are discussed.