Experimental evidence for male biased flight-to-light behavior in two moth species

Many studies report a greater abundance of male than female moths in light trap catches. The finding was interpreted as evidence for male-biased attraction to light, but alternatives could not be ruled out. For example, it is not known, how much the sex ratio in the catches deviates from the natural sex ratio. To overcome these limitations, we experimentally tested the flight-to-light behavior of two moth species, Yponomeuta cagnagella (Hübner) (Lepidoptera: Yponomeutidae) and Ligdia adustata (Denis and Schiffermüller) (Lepidoptera: Geometridae), under standardized conditions in an enclosed environment. In our test, we controlled the sex ratio, age, and population size. We recorded the moths caught in the trap and those that remained outside. Depending on the species, between 27 and 72% of all moths were caught in the light trap. We found that male moths were significantly and about 1.6 times more frequently attracted to the light than female moths. Our results were consistent for both species and hold good on the level of populations. We experimentally supported the general observation of a sexual dimorphism in the flight-to-light behavior of moths. Possible functional explanations include different flight activities of males and females or differences in the perception of light between males and females. Our experimental demonstration of a sexual dimorphism in the flight-to-light behavior of moths together with the common observation of an overrepresentation of males in light traps and other artificial light sources has implications for population and conservation biology.     

Monitoring oriental fruit moth (Lepidoptera: Tortricidae) with sticky traps baited with terpinyl acetate and sex pheromone

Studies in Argentina and Chile during 2010–2011 evaluated a new trap (Ajar) for monitoring the oriental fruit moth, Grapholita molesta (Busck). The Ajar trap was delta‐shaped with a jar filled with a terpinyl acetate plus brown sugar bait attached to the bottom centre of the trap. The screened lid of the jar was inserted inside the trap, and moths were caught on a sticky insert surrounding the lid. The Ajar trap was evaluated with and without the addition of a sex pheromone lure and compared with delta traps left unbaited or baited with a sex pheromone lure and a bucket trap filled with the same liquid bait. Studies were conducted in a sex pheromone‐treated orchard in Argentina and an untreated orchard in Chile. In Chile, the Ajar trap without the sex pheromone lure caught significantly fewer males, females and total moths than the bucket trap, and fewer males and more females than the sex pheromone‐baited delta trap. Total moth catch did not differ between the Ajar trap without a sex pheromone lure and the sex pheromone‐baited trap. Adding a sex pheromone lure to the Ajar trap significantly increased total moth catches to levels not different from those in the bucket trap. However, the Ajar trap with the sex pheromone lure caught significantly more males and fewer females than the bucket trap. In Argentina, the Ajar trap with or without the addition of a sex pheromone lure caught similar numbers of both sexes and total moths as the bucket trap. The sex pheromone‐baited delta trap caught <4% of the number of moths as these three traps. The bucket trap in both studies caught significantly more non‐targets than the delta and Ajar traps. Moth catches in the Ajar trap declined significantly after 2–3 weeks when the bait was not replaced.     

Weather-induced changes in moth activity bias measurement of long-term population dynamics from light trap samples

Interpretation of light trap catches of moths is complicated by daily variation in weather that alters flight activity and numbers caught. Light trap efficiency is also modified by wind and fog, and daily weather may effect absolute abundance (numbers actually present). However, actograph experiments and other sampling methods suggest that changes in daily activity are large by comparison to changes in absolute abundance. Daily variation in weather (other than wind and fog) is therefore a form of sampling error in absolute abundance estimates. We investigated the extent of this sampling bias in 26 years of population dynamics from 133 moth species. In a subset of 20 noctuid and geometrid species, daily numbers caught were positively correlated with temperature in 14 species, and negatively correlated with rainfall in 11 species. The strength of correlations varied between species, making it difficult to standardize catches to constant conditions. We overcame this by establishing how weather variation changed with time and duration of the flight period. Species flying later in the summer and for shorter periods experienced more variable temperatures, making sampling error greater for these species. Of the 133 moth species, those with shorter flight periods had greater population variability and more showed significant temporal density dependence. However, these effects were weak, which is encouraging because it suggests that population analyses of light trap data largely reflect factors other than sampling error.     

Comparison of four trap types for ambrosia beetles (Coleoptera, Scolytidae) in Brazilian Eucalyptus stands

Eucalyptus spp. plantations represent >60% of the reforested area in Brazil. Although ambrosia beetle attacks on live trees were at first nonexistent, they have begun to appear with greater frequency. Monitoring for pest insects is a key factor in integrated pest management, and baited traps are one of the most widely used methods for insect population detection and survey. We compared the efficiency of the most widely used trap in Brazil to survey for ambrosia beetles and other Scolytidae, the ESALQ-84 type, with other traditionally employed traps: the multiple funnel (Lindgren trap); drainpipe; and slot (Theyson) traps, in a Eucalyptus grandis Hill ex Maiden stand in Brazil. The ESALQ-84 trap was the most efficient in trapping Hypothenemus eruditus Westwood and Hypothenemus obscurus (F.); the multiple funnel trap caught significantly more Cryptocarenus diadematus Eggers; whereas the slot trap caught more Premnobius cavipennis Eichhoff and Xyleborus affinis Eichhoff than the other traps. The drainpipe trap was the least effective trap overall. When corrected for number of beetles caught per trap surface area, catches were significantly higher on the ESALQ-84 trap for the majority of the species analyzed, probably because of a smaller trap surface area. The slot trap was recommended for it caught overall more beetles of the three most economically important scolytid species in eucalypt plantations in Brazil, P. cavipennis, X. affinis, and X. ferrugineus.     

Genetic differentiation between alternate-year cohorts of Xestia tecta (Lepidoptera,Noctuidae) in Finnish Lapland

Several species in the noctuid genus Xestia exhibit periodic dynamics, with two coexisting cohorts flying in alternate years. The population dynamics and two-year life cycle of Xestia moths suggest that the two cohorts are more or less isolated in time. Typically one cohort is abundant and the other one is rare. Knowledge of the extent of isolation between the two cohorts is important to fully understand the population dynamics and the evolution of alternate-year flight in these species. We applied allozyme electrophoresis and mitochondrial genome sequencing to infer the extent of genetic differentiation among different cohorts of Xestia tecta (Hübner) within the same geographical area as well as between cohorts with opposite-phase flight pattern in different geographical regions. We found no evidence for substantial genetic differentiation and isolation between the even- and odd-year cohorts in eastern Lapland, nor between the cohorts in eastern and western Lapland. The most informative markers were the most polymorphic allozyme loci (Pgm and Mpi) and the AT-rich region in the mtDNA. However, owing to the generally low levels of genetic variation it was not possible to establish conclusively the degree of genetic isolation between the different cohorts. We discuss the implications of our results in relation to two different hypotheses which could account for this pattern: ongoing gene flow between different cohorts and recent common ancestry.     

A quarter of a century succession of epigaeic beetle assemblages in remnant habitats in an urbanized matrix (Coleoptera, Carabidae)

We studied the long-term (23-24 years) species turnover and succession of epigaeic beetle assemblages (Coleoptera: Carabidae, incl. Cicindelinae) in three remnant habitats [cottonwood (Populus spp.) and oak (Quercus spp.) stands, and old fields] that are embedded within highly urbanized areas in central Minnesota. A total of 9,710 beetle individuals belonging to 98 species were caught in three sampling years: 1980, 1981 and 2005 in pitfall traps in identical locations within each habitat. Results indicate that there were 2-3 times greater trap catches in 2005 than in 1980 (cottonwood and oak stands, and old fields) and 1.4-1.7 times greater species diversity of beetles in 2005 than in the 1980-1981 suggesting increased habitat association by beetles over time. Although there were no significant differences in catches between 2005 and 1981 (only cottonwood stands and old fields), there was a trend where more beetles were caught in 2005. At the species-level, 10 times more of an open-habitat carabid species, Cyclotrachelus sodalis sodalis LeConte, was caught in 2005 than in 1980. However, trap catches of five other abundant carabid species [Pterostichus novus Straneo, Platynus decentis (Say), Platynus mutus (Say), Calathus gregarius (Say), and Poecilus lucublandus lucublandus (Say)] did not change indicating population stability of some beetle species. These remnant habitats were increasingly colonized by exotic carabid species as Carabus granulatus granulatus Linneaus, Clivina fossor (Linneaus) and Platynus melanarius (Illiger), that were trapped for the first time in 2005. Species composition of epigaeic beetles was quite distinct in 2005 from 1980 with 39 species reported for the first time in 2005, indicating a high turnover of assemblages. At the habitat-level, greatest species diversity was in cottonwood stands and lowest was in old fields, and all habitat types in 2005 diverged from those in 1980s, but not cottonwood stands in 1981. As our sampled areas are among some of the last remnants of the original oak savanna habitats in central Minnesota, we hypothesize that conservation of these sites may be critical to maintaining epigaeic beetle assemblages under increased urbanization pressure.     

Use of forest corridors by boreal Xestia moths

Abstract We studied movements of the noctuid moths Xestia speciosa and X. fennica in a fragmented forest landscape including old-growth spruce forest corridors in eastern Finland. We individually marked and released 1,796 adults of the habitat generalist X. speciosa and 683 individuals of X. fennica, which prefers old-growth spruce forests. Moths were recaptured with 60 sugar-bait traps that were placed within habitat corridors, in the non-habitat matrix and in surrounding old-growth forest patches. Both species favoured the corridors during their movements and tended to avoid entering the matrix. We analysed recapture rates and movements of the recaptured moths. Results suggest that X. speciosa moves longer distances than X. fennica. Though corridors clearly canalized movements by both species, the impact of old-growth forest corridors at the larger landscape scale was less clear in X. fennica. Movement behaviour of the two sexes differed more than that of the two species.     

Pink bollworm moth （Lepidoptera： Gelechiidae） catches in the Imperial Valley, California from 1989 to 2003

We examined the patterns of male pink bollworm （PBW）, Pectinophora gossypiella （Saunders）, moth catches in gossyplure-baited traps over a 15-year period from 1989 to 2003 in the Imperial Valley, California, USA. Monitoring was conducted during periods when different pink bollworm areawide control strategies were being used. Numbers of male pink bollworm moths caught in gossyplure-baited traps progressively decreased each year from 1990 to 1994 during short-season cotton production. High numbers of male moths caught in traps from 1995 to 1997 may have been related to moth migrations from the large cotton acreages grown in the Mexicali Valley bordering the Imperial Valley. Transgenic Bollgard （Bt） cotton was planted in 3% of the cotton area in 1996 and thereafter in 80%- 94% of the cotton area from 1997 to 2003. Pink bollworm moth trap catches were significantly lower from 1998 to 2003 than catches in 1995 to 1997, except for 1999. The trapping results suggested that Bt cotton had significant input on reduction of pink bollworm populations, confirming results of other investigators and providing additional documentation on the benefits of the Bt cotton culture.     

Monitoring oriental fruit moth (Lepidoptera: Tortricidae) with the Ajar bait trap in orchards under mating disruption

Studies in Oregon, California, Pennsylvania and Italy evaluated the relative performance of the Ajar trap compared with several other traps for the capture of Grapholita molesta (Busck), in pome and stone fruit orchards treated with sex pheromone dispensers for mating disruption. The Ajar is a delta‐shaped trap with a screened jar filled with an aqueous terpinyl acetate plus brown sugar bait solution (TAS) that opens inside the trap and is surrounded by a sticky liner. The TAS‐baited Ajar trap was evaluated with and without the addition of a sex pheromone lure and compared with a delta trap baited with a sex pheromone lure and a bucket trap filled with the TAS bait. Although the Ajar trap had a 90% lower evaporation of the TAS bait than the bucket trap, both of them caught similar numbers in the majority of the field tests of both sexes of G. molesta. The addition of the sex pheromone lure did not increase moth catches by the TAS‐baited Ajar trap. The TAS‐baited Ajar trap caught significantly greater numbers of moths than the sex pheromone‐baited delta trap in 18 of the 20 orchards. Few hymenopterans were caught in orange TAS‐baited Ajar traps, but the catch of flies and other moths relative to the target pest remained high. Flight tunnel and field tests evaluated the effect of several screen designs on the catches of G. molesta and non‐target species. All exclusion devices significantly reduced the catch of larger moths. However, designs that did not reduce the catch of male G. molesta did not reduce the catch of muscid flies. Exclusion devices with openings <7.0 mm significantly reduced the catch of female G. molesta. The addition of (E)‐β‐farnesene, (E)‐β‐ocimene or butyl hexanoate septa lures to TAS‐baited Ajar traps significantly increased total moth catch. The addition of (E)‐β‐ocimene also significantly increased female moth catch.     

Design and elevation of sex-attractant traps for pea moth, Cydia nigricana (Steph.) and the effect of plume shape on catches

• 1 Catches of male pea moths in six designs of trap, each containing (E,E)-8,10-dodecadienyl acetate as an attractant, were compared; triangular-shaped traps caught most moths.
• 2 The vertical distribution of moths within a pea crop and the size of catches at different levels varied in different wind speeds. Three-quarter crop height is probably the optimum height for monitoring.
• 3 Five trap designs (including the triangular type) captured only 20–30% of individuals landing on them; water traps were slightly more efficient.
• 4 There was an eight-fold range in the number of moths caught depending on the sticky material used. ‘Bird-Tanglefoot’ was most effective.
• 5 Smoke plumes, emitted from different trap designs in the field to simulate plumes of attractant, were photographed and measured. The effect of trap design on plume shape was confirmed in wind tunnel tests.
• 6 Field tests showed that the more elongated the mean plume emitted from a trap the greater the catch.
• 7 The tracks of individual moths flying to traps are discussed in relation to current views on orientation to odour sources.

     

Long-term changes of aphid vectors of Barley yellow dwarf viruses in north-eastern Italy (Friuli-Venezia Giulia)

Migrations of aphid vectors of Barley yellow dwarf viruses (BYDV) were monitored using a Rothamsted Insect Survey suction trap in Friuli-Venezia Giulia (north-eastern Italy). Catches from 1983 to 2002 were studied for trends, correlations of total catches of each year with those of previous years, correlations between the autumn and the spring + summer catches of the same year and between spring + summer catches of one year with catches of the previous autumn. Infectivity of autumn alates was studied using biological tests, and infectivity indexes were calculated for all vector species and for Rhopalosiphum padi alone. Colonisation of barley and proportion of infected plants were checked in a field close to the suction trap from 1992 to 2002 and related to trap catches. Catches were also correlated to acreage dedicated to cereal and fodder crops in the region. During the 20 years, 15 BYDV vector species were caught in the trap, but only five species were found consistently colonising barley plants during autumn. R. padi was the most numerous species in catches, while Sitobion avenae was the predominant colonising species in the barley field. Relatively to R. padi , S. avenae colonies were about six times more numerous than expected from catches. The yearly abundance of catches of most species did not change significantly during the 20 years, with a few exceptions, significantly correlated to changes in the acreage dedicated to cereal and fodder crops. There was a significant decrease of the autumn catches of both R. padi and the total of BYDV vectors.     

Female sex pheromone of brinjal fruit and shoot borer,Leucinodes orbonalis (Lepidoptera: Pyralidae): trap optimization and application in IPM trials

Delta and wing traps baited with synthetic female sex pheromone of Leucinodes orbonalis Guenée were found to catch and retain ten times more moths than either Spodoptera or uni-trap designs. Locally-produced water and funnel traps were as effective as delta traps, although 'windows' cut in the side panels of delta traps significantly increased trap catch from 0.4 to 2.3 moths per trap per night. Trap catch was found to be proportional to the radius of sticky disc traps in the range 5-20 cm radius, discs with a 2.5 cm radius caught no moths. Wing traps placed at crop height caught significantly more moths than traps placed 0.5 m above or below the crop canopy. Replicated integrated pest management (IPM) trials (3 x 0.5 ha per treatment) were conducted in farmers fields with young and mature eggplant crops. Farmers applied insecticides at least three times a week in all check and IPM plots. In addition pheromone traps were placed out at a density of 100 per ha and infested shoots removed weekly in the 0.5 ha IPM plots. Pheromone trap catches were reduced significantly from 2.0 to 0.4 moths per trap per night respectively in check and IPM plots in a young crop and 1.1 to 0.3 moths per trap per night in check and IPM plots respectively in a mature crop. Fruit damage was significantly reduced from an average of 41.8% and 51.2% in check plots of young and mature crops respectively to 22% and 26.4 respectively in the associated IPM plots. Significant differences in pheromone trap catches and fruit damage were attained four and two weeks respectively after IPM treatments began in the mature crop whereas in the immature crop significant differences were not observed for the first eight to nine weeks respectively. The relative impact of removing infested shoots and mass trapping on L. orbonalis larval populations was not established in these trials but in both cases there was an estimated increase of approximately 50% in marketable fruit obtained by the combination of control techniques compared to insecticide treatment alone.     

Seasonality and density of emerging insects of a mixed lowland broadleaf-podocarp forest floor,Orongorongo Valley,New Zealand

Abstract

Emergence traps were used continuously for 2 years to determine the population density and seasonality of invertebrates in a mixed lowland broadleaf-podocarp forest near Wellington, New Zealand. A total of 53 920 individuals of 21 invertebrate orders was caught. Although more individuals were caught in the first year than in the second, this was not consistent amongst the different groups or species. Dipterans, staphylinid beetles, and solitary wasps were the most numerous insects caught. Diptera, Araneida, Opiliones, and Hymenoptera emerged from the forest floor in every month of the 2 year study. Many other invertebrate groups were active throughout the year but seasonal catches were significantly different with more recorded in summer than in other seasons. Numbers of several species were positively correlated with temperature. Likely effects of the extended invertebrate activity on the forest ecology are discussed.     

Sphaeroceridae (Diptera) caught in light traps at Rothamsted Experimental Station, Herts., 1980–83

ABSTRACT.

• 1 A total of 7063 specimens of Sphaeroceridae representing forty species were caught in four light traps, two in woodland and two in the open, at Rothamsted Experimental Station between December 1980 and December 1983.
• 2 A complete list of species and the numbers of individuals of each is provided.
• 3 The catches in the two traps in woodland were less diverse than the catches in the two traps in the open.
• 4 Two-way analysis of variance demonstrated a significant difference in catch from trap to trap.
• 5 When their similarities were compared, the four light trap catches formed two groups, corresponding with habitat type.
• 6 The majority of the catch were Copromyza similis (Collin) (5555 specimens or 78.64% of the total). The species was most abundant in winter from mid-December to early February, although there were slight differences in times of maximum abundance between open and woodland habitats.

     

Detection of Japanese Encephalitis Virus Genotype V in Culex orientalis and Culex pipiens (Diptera: Culicidae) in Korea

Japanese encephalitis virus (JEV) causes significant viral encephalitis and is distributed throughout the Asian countries. The virus is known to be transmitted by Culex tritaeniorhynchus, which mainly breeds in rice paddies in Korea. In this study, we investigated the presence of other mosquito species that can transmit JEV as a second or regional vector. We selected five cities where patients have experienced JE in the last 5 years as mosquito-collecting locations and subdivided them into four collection sites according to the mosquito habitats (cowshed, downtown area, forest, and swamp). Mosquitoes were caught using the BG-Sentinel trap, CDC black-light trap, Fay-Prince trap, and Gravid trap. A total of 993 pools from 22,774 mosquitoes were prepared according to their species, collection date, and site. We performed a SYBR Green 1-based real-time RT-PCR assay to detect JEV from the mosquito pools. A total of six JEV-positive pools were detected from Culex orientalis and Culex pipiens caught in the Gangwon-do and Gyeonngi-do provinces. All the detected JEVs were revealed as genotype V by phylogenetic analysis of the envelope gene. Our findings confirm that a new genotype of JEV was introduced in Korea and suggest that two mosquito species may play a role in JEV transmission.     

桃园中食心虫单一性诱芯及其复合配置的诱蛾效率比较

【目的】明确两种食心虫性诱芯复合配置的诱蛾效果,提高其监测或防治效率及其绿色环保化水平,为果树生产中食心虫的高效监测和绿色防控提供科学依据。【方法】田间系统调查研究了梨小食心虫(以下简称"梨小")、桃小食心虫(以下简称"桃小")单一性诱芯及其复合配置3种处理的诱蛾效率,并利用"Y"型嗅觉仪比较研究了其间梨小雄蛾趋向性的差异。【结果】(1)梨小和桃小性单一诱芯及其复合配置对梨小均具有引诱作用,其诱蛾总量依次为8 238.33、1 451.67、8 321.67头/诱捕器,其中第1、2、3代时复合配置诱蛾量最大,越冬代和第4代时梨小单一性诱芯诱蛾量最大,而各世代桃小单一性诱芯诱蛾量均最低。梨小单一性诱芯及其复合配置均监测到5个梨小发生高峰,且峰期基本一致,但复合配置的峰日诱蛾量均较高;桃小单一性诱芯仅监测到3个梨小发生高峰,且峰日诱蛾量亦较低。(2)桃小单一性诱芯及其复合配置对桃小均具有引诱作用,其诱蛾总量依次为4.00、2.33头/诱捕器,而梨小单一性诱芯对桃小无引诱作用。(3)"Y"型嗅觉仪研究发现,梨小食心虫对梨小和桃小各单一性诱芯及其复合配置均具有趋向作用,其趋向率依次为50.67%、8.67%、53.33%。【结论】梨小和桃小单一性诱芯复合配置对梨小诱捕量有微增效作用,而对桃小诱捕量有一定干扰作用,但影响均不显著。据此,该复合配置可用于桃园中梨小和桃小的监测与防控。     

Attraction of male gypsy and nun moths to disparlure and some of its chemical analogues

Summary The attractive power of disparlure—the sex attractant of the gypsy moth (Lymantria/Porthetria dispar)—vs. four synthetic analogous epoxides was tested in 1972 in a pine forest near Heidelberg. With two levels of concentration in the traps (2 and 20 g), a total of 1112 nun moths (Lymantria/Porthetria monacha) and 257 gypsy moths were caught in 9 experiments. Approximately equal percentages of the two species were caught with a given compound. Disparlure was by far the most effective attractant. The other substances were between three and twenty times less effective. These experiments support the assumption that disparlure is also at least part of the sexual attractant of the nun moth. In two additional experiments, moth captures by a series of increasing disparlure concentrations (2–100 g/trap) were determined. The catches of both species increased nonlinearly with the bait concentration. The experiments are discussed with respect to new (unpublished) electrophysiological recordings from disparlure receptor cells in both species. Special attention is given to the supposed masking effect of the disparlure precursor (an olefin). This substance is ineffective as an attractant, but has been reported to reduce the attraction of gypsy moth males to disparlure or to live females. However, the olefin elicits excitatory reactions in the same type of receptor cell that responds to disparlure and the related epoxides. Furthermore, no masking of the electrophysiological response was observed with the receptor cells when the olefin was added to disparlure.Supported by the Deutsche Forschungsgemeinschaft.     

Effect of weather factors on populations of Helicoverpa armigera moths at cotton-based agro-ecological sites

Pheromone trapping was used to monitor populations of the moth Helicoverpa armigera at five cotton‐based agro‐ecological sites – river, vegetable, orchard, forest and clean cultivation (areas under only cotton cultivation) – in the Bahawalpur district, Pakistan. Three locations at each site were chosen and three pheromone traps at each location were installed in cotton fields. Moth catches were recorded at 15–20 day intervals from 24 October 2004 to 19 December 2006. In 2004, the river sites showed the maximum trapped population of H. armigera (0.22/trap) followed by 0.165 per trap at the vegetable sites. Orchard, clean cultivation and forest sites had zero moth catches. In 2005, the river sites again showed the highest trapped population (0.57/trap), followed by clean cultivation (0.45/trap), vegetable (0.44/trap), orchard (0.40/trap) and forest (0.29/trap). The moths appeared during July to December and March to May. In 2006, sites showed non‐significant difference, with a population range of 0.47 to 0.97 moths per trap. On average, river sites peaked at 0.49 per trap, followed by vegetable (0.38), clean cultivation (0.47), orchard (0.35) and forest (0.25) sites. The peak was observed on 3 April 2006, and moths appeared during February to July and October to December. The minimum temperature in river, forest and clean cultivation sites; the maximum temperature in orchard sites; and the average temperature in river, orchard, forest and clean cultivation sites showed significant positive correlations with trapped moth populations. Relative humidity showed significant negative correlation with population at the orchard sites in 2005. All weather factors during 2004 and 2006 showed non‐significant correlations with the moth populations. No model was found to be best fit by multiple linear regression analysis; however, relative humidity, minimum temperature, maximum temperature, minimum temperature and maximum temperature contributed 8.40, 10.23, 2.43, 4.53 and 2.53% to the population fluctuation of the moth at river, vegetable, orchard, forest and clean cultivation sites, respectively.     

Test of nonhost angiosperm volatiles and verbenone to protect trap trees for Sirex noctilio (Hymenoptera: Siricidae) from attacks by bark beetles (Coleoptera: Scolytidae) in the northeastern United States

Sirex noctilio F. (Hymenoptera: Siricidae) is an invasive woodwasp, currently established in northeastern North America. In other regions of the world, stressed trap trees are used to monitor populations of S. noctilio and to provide inoculation points for the biological control nematode Deladenus siricidicola Bedding. However, the operational use of trap trees for S. noctilio in North America may be compromised by the large community of native organisms that inhabit stressed and dying pine trees. Common bark beetles such as Ips pini (Say) and Ips grandicollis (Eichhoff) (Coleoptera: Scolytidae) could potentially compete with S. noctilio and associates for resources on trap trees, possibly reducing the efficacy of trap trees as habitats for the woodwasp. In an attempt to develop a technology to mitigate this potential issue, three common semiochemical interruptants--conophthorin, green leaf volatile mix, and verbenone--were tested for effectiveness in reducing arrivals of I. pini and I. grandicollis on trap trees treated with herbicides in northeastern United States. In addition, the effects of these compounds were determined independently with pheromone-baited multiple-funnel traps. None of the interruptants reduced numbers of I. pini or I. grandicollis either arriving on trap trees or caught in pheromone-baited traps. However, verbenone increased catches of I. grandicollis in traps baited with its pheromone, ipsenol. The mix of green leaf volatiles reduced catches of a native ambrosia beetle, Gnathotrichus materiarius (Fitch), whereas verbenone reduced trap catches of an exotic ambrosia beetle, Xylosandrus germanus (Blandford). Catches of X. germanus in traps adjacent to trap trees were enhanced with conophthorin.     

Effects of habitat type and trap placement on captures of bark (Coleoptera: Scolytidae) and longhorned (Coleoptera: Cerambycidae) beetles in semiochemical-baited traps

Two studies were conducted to determine the effect of habitat selection and trap placement on catches of Scolytidae and Cerambycidae (Coleoptera) in northeastern U.S. forests. In a nonreplicated case study, four habitat types--closed canopy hardwood stand, closed canopy conifer stand, a low-intensity thinned Pinus strobus L. stand, and a high-intensity thinned P. strobus stand--were surveyed using alpha-pinene, ethanol, ipsenol, ipsdienol, and lanierone. Average trap catches, species richness, and the number of unique species captured were all highest in at least one of the thinned habitats. A second experiment that was replicated evaluated the placement of traps in relation to habitat patches. Semiochemical-baited traps (alpha-pinene and ethanol) were placed under a closed canopy forest, along an edge, and in a clearing and tested for effects on Scolytidae and Cerambycidae trap catches. Abundance and species richness were generally higher in the closed canopy and edge placements compared with traps in the open area. The highest number of unique species were captured in the edge and clearing.