bluuebunny/crossref_metadata_2025 huggingface dataset:
Sexual size dimorphism in a natural population of Callicorixa vulnerata (Hemiptera: Corixidae)
Authors: Nosil P.
Published: November 2009

Sexual size dimorphism occurs in many species. Differences between males and females, in size or other characteristics, may result from sexual selection, fecundity selection, natural selection, non-adaptive processes, or a combination of these pressures (Darwin 1874; Selander 1966; Trivers 1976; Slatkin 1984; Shine 1989). In insects, females with large body size often produce more eggs than smaller females, and femalebiased sexual size dimorphism is commonly attributed to such fecundity selection (e.g., Preziosi and Fairbairn 1997; but see Leather 1988). Water boatmen are detrivorous or zoophagous aquatic insects often inhabiting small ponds of the Northern Hemisphere (Hungerford 1948; Nosil and Reimchen 2001). Female water boatmen are generally larger than males. In this note, I quantify the nature and magnitude of a previously undescribed sexual size dimorphism in a natural population of the water boatman Callicorixa vulnerata Uhler (Hemiptera: Corixidae). I tested for differences between males and females in mean trait size (body length, body weight, mid-leg tarsal length, mid-leg tarsal spine number), and also tested for sexual dimorphism in allometric relationships between tarsal traits and body length.
Differences in activity enhancement of a baculovirus by an optical brightener between Choristoneura fumiferana and Choristoneura occidentalis (Lepidoptera: Tortricidae)
Authors: Li S.Y. , Otvos I.S.
Published: November 2009

Optical brighteners were recently discovered to function as UV protectants for baculoviruses of insects (Shapiro 1992) and, also, to enhance entomopathogenic activity of these viruses (Hamm and Shapiro 1992; Li and Otvos 1999a). Enhancement of viral activity by brighteners varied greatly from one virus–host system to another: for example, from 1500-fold in LdMNPV against Lymantria dispar (L.) (Lepidoptera: Lymantriidae) (Argauer and Shapiro 1997) to 2- to 13-fold in a multicapsid nuclear polyhedrosis virus of Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae) (CfMNPV) against Choristoneura occidentalis Freeman (Li and Otvos 1999a). The reason for this variation in enhancement of viral activity is still unknown. In this study, we used CfMNPV to compare the levels of viral enhancement by an optical brightener between C. occidentalis and C. fumiferana.
Effect of apple-orchard structure on interception of Rhagoletis pomonella (Diptera: Tephritidae) flies by odor-baited traps
Authors: Rull Juan , Prokopy Ronald J.
Published: November 2009

We released marked mature male flies of the apple maggot, Rhagoletis pomonella (Walsh), inside and outside of square blocks of apple trees, Malus domestica Borkh. (Rosaceae), to test the effect of orchard structure on the interception of flies by odor-baited red-sphere traps. The blocks were composed of large trees planted at low density, medium-sized trees planted at medium density, or small trees planted at high density. The experiment was carried out in six commercial apple orchards during summer in 1997 and 1998. Released flies moving into blocks were intercepted in large proportions by baited perimeter traps, thus preventing fly penetration into sphere-protected blocks. In 1997, proportions of intercepted flies were higher for traps in blocks of small and medium-sized trees than for traps in blocks of large trees. In 1998, a year with an unusually low fruit load, interception remained high, but there were no differences in proportions of flies intercepted by perimeter traps among blocks of trees of different sizes. Overall we conclude that the tendency of apple growers in Massachusetts to replace large trees planted at low density with small or medium-sized trees planted at high or medium density will not adversely affect behavioral control programs for apple maggot flies. In fact, this practice may enhance the effectiveness of these programs through increased interception of immigrant adults.
Latitudinal variation in Dendroctonus ponderosae (Coleoptera: Scolytidae) development time and adult size
Authors: Bentz B.J. , Logan J.A. , Vandygriff J.C.
Published: November 2009

Dendroctonus ponderosae (Hopkins) is widely distributed across western North America, feeding in at least 12 native species of Pinus L. (Pinaceae). We investigated the existence of heritable differences in two life-history parameters (adult size and development time) of D. ponderosae from a northern population (central Idaho, Pinus contorta Douglas ex Loudon) and a southern population (southern Utah, Pinus ponderosa Douglas ex P. and C. Lawson). We attempted to separate heritable from environmental effects by rearing individuals from both populations through two generations (F1 and F2) in a common standardized laboratory environment with a constant temperature. Two treatment effects were tested for in the F2 generation: (1) geographic location (source host) for F0D. ponderosae; and (2) the F2 brood host. We hypothesized that, if differences were observed and the F0 source host and region had a greater effect on F2 brood development time and adult size than did the host in which F2 brood were reared, a heritable factor related to the F0 parents was responsible. Time to emergence was significantly shorter for second-generation offspring of the northern population than for second-generation offspring of the southern population, regardless of the F2 brood host. Although both the F2 brood host and F0 source parents were significant in explaining differences observed in the developmental-time distribution of F2 brood, the F0 source effect was found to be much greater. Also, F2 males and females from southern source parents were significantly larger than F2 brood from northern source parents when reared in both F2 brood hosts. Geographic region and original host of F0 source parents had a significant effect on F2 offspring size, whereas the immediate food for F2 brood was not significant in explaining differences. These results suggest genetically based regional differences in D. ponderosae populations.
Olfactory behavior of convergent lady beetles (Coleoptera: Coccinellidae) to alarm pheromone of green peach aphid (Hemiptera: Aphididae)
Authors: Acar E.B. , Medina J.C. , Lee M.L. , Booth G.M.
Published: November 2009

A previous investigation from our laboratory showed that the odor of live green peach aphids,Myzus persicae(Sulzer), highly attracts the convergent lady beetle,Hippodamia convergensGuérin-Méneville. In this study, we isolated the odor and identified it as (E)-β-farnesene (an aphid alarm pheromone) using gas chromatography – mass spectrometry. The olfactory response of the convergent lady beetle to (E)-β-farnesene was investigated using an eight-arm air-flow olfactometer and tracing the pathways of the lady beetles. The results clearly indicate thatH.convergenscan perceive and orient to (E)-β-farnesene released by green peach aphids. These findings suggest that this species of lady beetle has evolved a sensory system for detecting the green peach aphid alarm pheromone as a means of finding its prey.
Cone entomofauna of whitebark pine and alpine larch (Pinaceae): potential impact of Leptoglossus occidentalis (Hemiptera: Coreidae) and a new record of Strobilomyia macalpinei (Diptera: Anthomyiidae)
Authors: Anderton Laurel K. , Jenkins Michael J.
Published: November 2009

Laboratory and field feeding tests with Leptoglossus occidentalis Heidemann demonstrated that both immature and mature seed bugs can use cones and foliage of whitebark pine, Pinus albicaulis Engelmann, as a food source for 1- to 2-week periods. Damage to unprotected whitebark pine cones by seed bugs ranged from 0.3 to 2.1% of seeds per cone. Total insect damage ranged from 0.4 to 7.1% of seeds per cone. A seed chalcid, Megastigmus Dalman. sp. (Hymenoptera: Torymidae), was documented for the first time on whitebark pine and was found in 4.7% of examined seeds at one site. The larch cone fly, Strobilomyia macalpinei Michelsen, was reared from cones of alpine larch, Larix lyallii Parl., from the Bitterroot Range of Montana. This is the first record of this species in the United States and the first since its description in 1988. Ninety-four percent of a sample of alpine larch cones were damaged by cone fly larvae and 64% contained larvae or puparia.
Stimuli increasing oviposition by female coffee white stem borer (Coleoptera: Cerambycidae)
Authors: Rhainds Marc , Warndorff Maarten , Chiew Phang Kok , Lan Chin Chiew , Gries Gerhard
Published: November 2009

The coffee white stem borer, Xylotrechus quadripes (Chevrolat) is a major pest of coffee, Coffea arabica (L.) (Rubiaceae), in South Africa, India, Thailand, and China (Duffy 1968; Schoeman 1990; Visitpanich 1994; Montavon 1997). Females lay eggs singly or in batches, generally under bark crevices of the stem. Neonatal larvae feed beneath the bark and, during development, bore deeply inside the stem. Stems are colonized by up to 60 larvae. Extensive damage by larvae causes mortality of coffee plants or reduction of fruit production (Duffy 1968; GK veeresh). Because larvae inside the stems of coffee plants are difficult to control, management tactics are aimed at preventing infestation, either by interfering with oviposition of females or by killing neonates before they bore into the stem. Our study tested insect and host plant derived stimuli that may affect the selection of oviposition sites by female X. quadripes.
Impacts of seasonal kaolin particle films on apple pest management
Authors: Knight A.L. , Christianson B.A. , Unruh T.R. , Puterka G. , Glenn D.M.
Published: November 2009

The impact of multiple applications of the kaolin-based particle film M96-018 on the population density of selected pests of apple, Malus domestica (Borkh) (Rosaceae), and their natural enemy populations were measured in several Washington State orchards from 1997 to 1999. Densities of western tentiform leafminer, Phyllonorycter elmaella (Doganlar and Mutuura) (Lepidoptera: Gracillariidae), were significantly higher and percent parasitism was generally lower in treated plots than in untreated plots. The effect of M96-018 on green aphids (Aphis spp.) (Hemiptera: Aphididae) was variable between orchards; however, populations of rosy apple aphid, Dysaphis plantaginea Passerini (Hemiptera: Aphididae), were higher in treated plots than in untreated plots. M96-018 reduced the mean density of the white apple leafhopper, Typhlocyba pomaria (McAtee) (Hemiptera: Cicadellidae), and the density of spiders (Araneae) compared with untreated plots. Fruit injury by codling moth, Cydia pomonella (L.), and fruittree leafroller, Archips argyrospilus (Walker) (Lepidoptera: Tortricidae), was significantly reduced in the treated plots compared with the untreated plots. The effect of M96-018 on the mullein bug, Campylomma verbasci (Meyer) (Hemiptera: Miridae), was variable between orchards and years. Stink bug (Hemiptera: Pentatomidae) density and related fruit injury were unaffected by M96-018. Fruit infestation by San Jose scale, Quadraspidiotus perniciosus (Comstock) (Hemiptera: Diaspididae), was significantly higher in treated plots than in untreated plots. Discontinuing applications of M96-018 at mid-season reduced the number of aphid-infested leaves and increased fruit injury by leafroller compared with a full-season program. No differences in pest densities occurred in plots treated for one versus two consecutive years; however, the density of phytophagous mites (Acari: Tetranychidae) was significantly higher the subsequent year after plots were treated with M96-018. Further studies are needed to elucidate how these disruptive impacts of particle films can be minimized.
Flies and flowers: taxonomic diversity of anthophiles and pollinators
Authors: Larson B.M.H. , Kevan P.G. , Inouye D.W.
Published: November 2009

The Diptera are the second most important order among flower-visiting (anthophilous) and flower-pollinating insects worldwide. Their taxonomic diversity ranges from Nematocera to Brachycera, including most families within the suborders. Especially important are Syrphidae, Bombyliidae, and Muscoidea. Other families, especially of small flies, are less appreciated and often overlooked for their associations with flowers. We have compiled records of their flower visitations to show that they may be more prevalent than usually thought. Our knowledge of anthophilous Diptera needs to be enhanced by future research concerning (i) the significance of nocturnal Nematocera and acalypterate muscoids as pollinators, (ii) the extent to which the relatively ineffective pollen-carrying ability of some taxa can be compensated by the abundance of individuals, and (iii) the role of Diptera as pollinators of the first flowering plants (Angiospermae) by using phylogenetic and palaeontological evidence. Specializations in floral relationships involve the morphology of Diptera, especially of their mouthparts, nutritional requirements, and behaviour, as well as concomitant floral attributes. The South African flora has the most highly specialized relations with dipterous pollinators, but in arctic and alpine generalist fly–flower relations are important in pollination and fly nutrition.
Feeding preferences, growth, and development of Mamestra configurata (Lepidoptera: Noctuidae) on Brassicaceae
Authors: Ulmer B. , Gillott C. , Erlandson M.
Published: November 2009

The growth (increase in body mass) and development (progression to specific instar) of the bertha armyworm, Mamestra configurata Walker, were examined using up to 14 plant lines from five species of brassicaceous plants. Varietal and breeding lines of Brassica napus L., B. juncea L., B. rapa L., B. carinata L., and Sinapis alba L. were selected on the basis of differing seed and foliar glucosinolate levels. No-choice feeding experiments were conducted with larvae isolated on leaf discs, individual leaves, or entire plants of each line. The no-choice tests showed that M. configurata weight gain and development varied significantly among host plants tested. Two B. juncea lines (AC Vulcan and H-Allyl) and the S. alba lines (AC Pennant and L-GS) were the poorest hosts in terms of larval weight gain, and the two B. juncea lines also significantly slowed development relative to the other lines tested. Mamestra configurata feeding preference, which was examined using a series of paired leaf disc choice tests, was also significantly different among the lines examined. Two B. juncea lines (AC Vulcan and H-Allyl) were significantly less preferred than all the other lines examined. The data extends previous work indicating that specific foliar glucosinolates, such as sinigrin, which is predominant in B. juncea, and sinalbin, which is abundant in S. alba, may provide brassicaceous crops with some protection from M. configurata. Thus, it may be possible to use foliar glucosinolate levels as predictors of M. configurata feeding damage in the development of breeding lines for the genus Brassica.
Protogyny, protandry, and bimodal emergence patterns in necrophagous Diptera
Authors: Buck Matthias
Published: November 2009

The emergence patterns of Diptera breeding in small-sized and buried carrion were studied in rearing experiments with field-exposed baits. Development times are reported for 52 species in the families Phoridae, Sphaeroceridae, Sepsidae, Heleomyzidae, Anthomyiidae, Fanniidae, Muscidae, Sarcophagidae, Psychodidae, and Sciaridae. Most species showed a synchronous emergence of males and females. Protandry was detected in Hydrotaea ignava (Harris) (Muscidae), H. palaestrica (Meigen), and Psychoda minuta (Banks) (Psychodidae). Protogyny was found in several species of Phoridae, namely Conicera similis (Haliday), C. schnittmanni Schmitz, Anevrina unispinosa (Zetterstedt), and Triphleba dudai (Schmitz). Conicera schnittmanni and T. dudai showed two discrete emergence periods for each sex, which is due to a delayed emergence of some specimens. Protogyny is a rare phenomenon in Diptera and insects in general, and has never been reported before in Phoridae. The significance of protogyny could not be ascertained in the examined species, because of insufficient information on their mating systems and female receptivity patterns.
Factors influencing oviposition by Sitodiplosis mosellana (Diptera: Cecidomyiidae) on wheat spikes (Gramineae)
Authors: Smith M.A.H. , Lamb R.J.
Published: November 2009

Factors that might contribute to variability in the densities of wheat midge eggs, Sitodiplosis mosellana (Géhin), on common and durum wheats, Triticum aestivum L. and Triticum durum Desf., were investigated to improve the quantification of oviposition preferences in relation to crop resistance. Egg densities on wheat spikes were highly variable, with a similar contagious distribution in the laboratory and field, although variance was highest in the laboratory. Females laid eggs in small groups, usually of one to six eggs; most infested spikes had more than one egg group. Females showed no preference for ovipositing on different parts of a spike, although spikelets on one side and at the base often received fewer eggs because these spikelets were covered by the flag leaf and inaccessible for longer than others. Oviposition rates varied from night to night, probably related to the weather. Females showed no preference for spikes at different growth stages, from the time spikes began to emerge until at least flowering. Spike size did not affect egg density, and spike height was a factor only for spikes deep within or protruding above the canopy. Sources of environmental variation such as effects of weather on oviposition rates in the field or spatial phenomena in cages were measurable but of secondary importance. In the field, comparisons among spikes which emerged on the same day could reduce variation in egg density. In the laboratory, variation in egg density could be reduced by using arrays of excised spikes arranged at the same height, leaving the central portion of the array empty. The primary cause of high variability in egg density among spikes was variation in egg-group size and the presence of multiple egg groups on a single spike, factors which cannot be experimentally controlled because they are the result of oviposition behaviour rather than environmental heterogeneity.
Seasonal occurrence, species composition, and parasitism of Lygus spp. in alfalfa, canola, and mustard
Authors: Braun L. , Erlandson M. , Baldwin D. , Soroka J. , Mason P. , Foottit R. , Hegedus D.
Published: November 2009

Field collections of over-wintering and summer adults and nymphs of Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), Lygus borealis (Kelton), and Lygus elisus Van Duzee were made weekly in five fields in Saskatchewan in 1998 and 1999. The crops sampled were alfalfa, Medicago sativa L. (Leguminosae), canola, Brassica napus L. (Cruciferae), and mustard, Sinapis alba L. (Cruciferae), at Vonda, and alfalfa and canola at Saskatoon. In alfalfa, the most abundant Lygus spp. found in May and June were over-wintering adult L. lineolaris and (or) L. borealis; the predominant species in mid-June to early July was L. borealis; and the population from mid-July to late August was dominated by L. lineolaris. In canola, adult populations of Lygus spp. were not found until mid-June. The predominant species, L. lineolaris, probably over-wintering adults, was first detected in canola at the early bud stage in late June to early July; high numbers of L. lineolaris adults occurred in canola in mid-August. Populations of Lygus spp. in organic mustard were negligible. Dissections of field-collected Lygus spp. nymphs revealed parasitism in up to 70% of the midsummer population in alfalfa. In contrast, less than 1% of the late-season Lygus spp. population, primarily L. lineolaris in canola and L. lineolaris and L. borealis in alfalfa, was parasitized.
Growth loss and recovery following defoliation by the balsam fir sawfly in young, spaced balsam fir stands
Authors: Piene Harald , Ostaff Don P. , Eveleigh Eldon S.
Published: November 2009

Two stands of intensively managed balsam fir [Abies balsamea (L.) Mill. (Pinaceae)] in western Newfoundland, located within an area infested by the balsam fir sawfly, Neodiprion abietis (Harr.) (Hymenoptera: Diprionidae) complex, were selected to study growth loss and recovery following severe defoliation by the balsam fir sawfly in the early 1990s. Four years after the start of the outbreak, volume increments were reduced by 78–81%. The decreased volume increment and recovery coincided well with the balsam fir sawfly outbreak and decline. The growth recovery rates following severe balsam fir sawfly defoliation were slow due to the absence of bud destruction, which triggers the release of suppressed buds, and thus increases foliage production. It is imperative that the severe losses in volume growth caused by balsam fir sawfly defoliation are incorporated into wood supply analyses so that future annual allowable cuts may be adjusted. In addition, to ensure maximum recovery rates at the end of an outbreak, future populations must be kept at a minimum to avoid additional foliage loss.
Tree size and growth history predict breeding densities of Douglas-fir beetles in fallen trees
Authors: Reid M.L. , Glubish S.S.
Published: November 2009

For bark beetles (Coleoptera: Scolytidae) breeding in fallen trees, the tree characteristics that are associated with higher breeding densities are poorly known. The breeding densities of Douglas-fir beetles,Dendroctonus pseudotsugaeHopkins, in freshly felled Douglas-fir,Pseudotsugae menziesii(Mirb.) Franco, were examined with respect to tree diameter, phloem thickness, and several measures of tree growth rate over the past year to 10 years prior to tree death. Trees were felled in 8 decks of 3–12 trees to provide a range of tree qualities in a given location. Stepwise regression revealed that of the tree characteristics measured, only diameter was needed to explain the density of beetle attacks on trees within decks. Because diameter, phloem thickness, and growth-increment measures were all highly correlated, attack density also increased with phloem thickness and growth rate prior to felling when these measures were analyzed individually. The apparent preference for larger trees with thicker phloem is consistent with published results for live trees, but the positive effect of tree growth rate prior to death is contrary to results for beetles attacking live trees. Thus, assessments of stand susceptibility to bark beetles based on tree growth rate may differ depending on whether beetles are initially breeding in live or dead trees.
Size influences male mating success in the alfalfa blotch leafminer (Diptera: Agromyzidae)
Authors: Andersen Arild , McNeil Jeremy N.
Published: November 2009

Male size is an important parameter in mate choice for many species and has been associated with such female life-history parameters as increased fecundity or fertility and larger progeny (Phelan and Baker 1986; Savalli and Fox 1998, 1999; Brown 1999). In the alfalfa blotch leafminer, Agromyza frontella (Rondani), intraspecific larval competition may significantly influence the size of both males and females (Quiring and McNeil 1984a). The influence of female size on female reproductive success has been studied (Quiring and McNeil 1984b, 1984c), but to date, no attention has been given to the possible effects of male size. The objectives of this study were to determine if differences in male size, the result of intraspecific larval competition, affected male longevity and reproductive success, as well as various parameters of female reproduction.
Development, larval voracity, and greenhouse releases of Stethorus punctillum (Coleoptera: Coccinellidae)
Authors: Raworth D.A.
Published: November 2009

Stethorus punctillum Weise (Coleoptera: Coccinellidae) is a Palearctic species first found in North America in the 1940s (Putman 1955). Commercial mass-rearing methods were developed in the late 1990s (Agriculture and Agri-Food Canada, London, Ontario, and Applied Bio-nomics Ltd, Saanich, British Columbia). The beetle is now released in North America to control two-spotted spider mites, Tetranychus urticae Koch (Acari: Tetranychidae). Knowledge of the life-history traits of S. punctillum is necessary for effective use of the predator in greenhouses. Putman (1955) provides useful information, but his results cannot be readily interpreted with respect to larval voracity, lower developmental temperature threshold, and developmental time in degreedays (°d), traits that affect efficacy. In this note I report new results relating to these life-history traits and to beetle releases in greenhouse vegetable crops.
Mycobatidae (Acari: Oribatida) of Pacific Northwest canopy habitats
Authors: Behan-Pelletier Valerie M. , Eamer Barbara , Clayton Marilyn
Published: November 2009

Three new species of oribatid mites in two genera of Mycobatidae are recorded from canopy habitats of coniferous temperate rainforest and montane forest in the Pacific Northwest of North America. These species,Mycobates acuspidatussp.nov.,M.corticeussp.nov., andZachvatkinibates epiphytossp.nov., are described on the basis of adults and immatures. The previous key for adultMycobatesspecies of America north of Mexico is modified to include these new species, and a key for adults is given for the three species ofZachvatkinibatesnow known from North America.
Revision of the genusHolocephalus(Coleoptera: Scarabaeidae: Scarabaeinae: Coprini)
Authors: Smith Andrew B.T. , Génier François
Published: November 2009

The genusHolocephalusHope is revised and now contains five species:H.cristatus(Gillet),H.eridanus(Olivier),H.julienisp.nov.,H.sculptus(Gillet), andH.simonisp.nov. All taxa are described and illustrated. A key to species ofHolocephalusis included. Lectotypes are designated forH.eridanusandH.sculptus.Scarabaeus eridanusOlivier is designated as the type species for the generic nameAtrichiusGillet (a junior synonym ofHolocephalus).
Field evaluation of nine families of honey bees for resistance to tracheal mites
Authors: van Engelsdorp Dennis , Otis Gard W.
Published: November 2009

We evaluated the resistance to tracheal mites, Acarapis woodi (Rennie) (Acari: Tarsonemidae), of colonies of honey bees, Apis mellifera L. (Hymenoptera: Apidae), headed by daughters of three queens from each of three honey bee stocks: (i) British Columbia "mite-resistant stock, (ii) Buckfast "mite-resistant" stock, and (iii) Canadian unselected stock. Colonies of all nine families were distributed among four apiaries; half of the colonies in each apiary were treated with formic acid to attempt to control tracheal mites. The study documented significant differences in resistance to tracheal mites among the families of bees, even within each of the three stocks. After the first 4 months of study (by November 1993), differences in mite infestations had developed among the nine families. Formic acid treatments had either short-lived effectiveness (1993) or no effect (1994) on tracheal mite infestations, thereby eliminating the opportunity to evaluate colony performance in the absence of mites. Mite infestations varied significantly among apiary sites. This study highlights the value of evaluating sets of colonies headed by sister queens when identifying mite-resistant stock for breeding purposes.
Physiological basis for flexible voltinism in the spruce beetle (Coleoptera: Scolytidae)
Authors: Hansen E. Matthew , Bentz Barbara J. , Turner David L.
Published: November 2009

The spruce beetle, Dendroctonus rufipennis (Kirby), has described life cycles of 1–3 years. Although temperature has been shown to be strongly associated with flexible voltinism in the spruce beetle, the physiological basis for this phenomenon is not clear. Two competing hypotheses were tested under laboratory conditions. First, we tested the hypothesis that larval diapause, induced by cool temperatures during or before instar III, initiates prolonged life cycles while larvae not diapausing complete development to adults before the first winter. We compared development times at constant temperature (12 °C) and field-simulated thermoperiod treatments against development times in a reference (21 °C) treatment for which there is no indication of diapause induction. The constant temperature treatment was not significantly different than the reference treatment, although there were a few outliers. The thermoperiod treatment was significantly longer than the reference treatment, but only by a few days. These results provide little support for the hypothesis of larval diapause induction during or before instar III. Second, we investigated the hypothesis of life-cycle regulation through life stage specific developmental temperature thresholds, particularly, a relatively high threshold for pupation that might prevent development beyond the prepupal life stage under cool conditions. We found little evidence of distinct differences in low-temperature thresholds between life stages. Instar-IV larvae held at ≤ 15 °C, however, did not pupate for 125–300 days, a developmental arrest that suggests diapause. Based on all present and previous investigations, the induction-sensitive phase appears to be late in the instar-IV or early in the prepupal stages. For semivoltine spruce beetles, this life stage occurs late in the growing season, after most temperature-dependent development has been completed. It is our conclusion that spruce beetle voltinism is primarily under direct temperature control and that prepupal diapause is the default overwintering strategy for individuals not completing development to maturity by fall.
Effects of encapsulation on the toxicity of insecticides to the Oriental fruit moth (Lepidoptera: Tortricidae) and the predatorTyphlodromus pyri(Acari: Phytoseiidae)
Authors: Pogoda M.K. , Pree D.J. , Marshall D.B.
Published: November 2009

We assessed the effects of microencapsulation on the toxicity of chlorpyrifos, cypermethrin, and lambda-cyhalothrin to larvae of the Oriental fruit moth,Grapholita molesta(Busck), in the laboratory and the field. We also compared the toxicity of microencapsulated and traditional formulations to pyrethroid-susceptible and pyrethroid-resistant populations of the predaceous miteTyphlodromus pyriScheuten in the laboratory. In laboratory bioassays with neonate larvae ofG.molesta, the microencapsulated formulations of chlorpyrifos and cypermethrin were less toxic than the wettable-powder and emulsifiable-concentrate formulations. The emulsifiable-concentrate and microencapsulated formulations of lambda-cyhalothrin were equally toxic. In the field, all trees in insecticide-treated plots contained less damage by first generationG.molestalarvae than unsprayed controls. In the second generation, the microencapsulated formulations of cypermethrin and chlorpyrifos were generally less effective than the emulsifiable-concentrate formulation of cypermethrin. The microencapsulated formulation of lambda-cyhalothrin was as effective as the emulsifiable-concentrate formulation. The microencapsulated formulation of cypermethrin was less toxic than the emulsifiable-concentrate formulation to both pyrethroid-susceptible and pyrethroid-resistant populations ofT.pyri. Both populations were highly resistant to chlorpyrifos and unaffected by either formulation. The microencapsulated formulation of lambda-cyhalothrin affected the two populations ofT.pyridifferently; the microencapsulated formulation was approximately fivefold more toxic than the emulsifiable-concentrate formulation to the pyrethroid-susceptible population, but sixfold less toxic than the emulsifiable-concentrate formulation to the pyrethroid-resistant population. Much of the selectivity reported for the microencapsulated formulations of cypermethrin and chlorpyrifos appeared related to a general reduction in toxicity to both target insects and beneficial mites. The microencapsulated lambda-cyhalothrin was as toxic as the emulsifiable-concentrate formulation to the target insect but was less toxic than the emulsifiable concentrate to pyrethroid-resistant predator mites. This limited increased selectivity may be useful where resistant populations of predators occur.
Spatial heterogeneity of low-density populations of Melanoplus sanguinipes (Orthoptera: Acrididae) associated with grazing and vegetation treatments
Authors: Fielding Dennis J. , Brusven M.A. , Shafii Bahman , Price William J.
Published: November 2009

The objectives of this study were to determine whether the spatial distribution of Melanoplus sanguinipes F., the most abundant species of grasshopper on rangeland in southern Idaho, varied annually in response to changing patterns of grazing and to investigate how vegetation affects the spatial distribution of low-density populations of M. sanguinipes at scales relevant to most rangeland-management activities. A lattice of 72 sites was established across nine pastures, covering approximately 5000 ha. At each site, densities of M. sanguinipes, percent canopy coverage by plant species, and percent forage utilization by livestock were estimated twice per year, in June when M. sanguinipes was in the nymphal stage and in August during the adult stage, for 4 years, 1991–1994. Spatial analyses of variance were used to evaluate the influence of grazing and vegetation type on densities of M. sanguinipes. In August of each year, densities of M. sanguinipes were lower on heavily grazed sites than on lightly grazed sites, except in 1993, when the opposite trend was observed. Above-normal precipitation in 1993 resulted in abundant growth of annual forbs and regrowth of grazed plants. The distribution of nymphs in June of 1993 and 1994 reflected the grazing patterns of the previous summer. Densities of M. sanguinipes were lower on crested wheatgrass habitats than on annual grasslands for every sampling period from June 1991 to June 1993, after which no differences were observed. We interpret the results to suggest that grazing effects on low-density populations of M. sanguinipes were contingent on weather conditions; under dry conditions, grazed habitats were less favorable to M. sanguinipes but, during relatively cool wet summers, grazing created conditions that were more favorable to M. sanguinipes.
Feeding by Leptoglossus occidentalis (Hemiptera: Coreidae) reduces seed set in lodgepole pine (Pinaceae)
Authors: Strong Ward B. , Bates Sarah L. , Stoehr Michael U.
Published: November 2009

Low seed set is a serious problem in seed orchards of lodgepole pine (Pinus contorta var. latifolia Engelmann) in the southern interior of British Columbia. We tested the hypothesis that Leptoglossus occidentalis Heidemann is responsible for the low seed set. Cones enclosed in insect exclusion bags as part of a pollination experiment produced significantly more filled seeds per cone than cones that were not bagged. In a separate bagging experiment, cones that were enclosed with a L. occidentalis female and her progeny produced only about one filled seed per cone, compared with about 28 seeds in bagged control cones. Changes in microclimate associated with the use of bags did not appear to be responsible for the observed increase in seed set in bagged cones. Leptoglossus occidentalis was also excluded from trees using the insecticide fenvalerate. Cones on fenvalerate-treated trees produced > 11 filled seeds per cone, whereas water-treated (control) cones produced < 1.7 filled seeds. These data suggest that L. occidentalis should be considered a serious pest in lodgepole pine seed orchards.
New species of the genus Phtheiropoios (Phthiraptera: Gyropidae), parasitic on Ctenomys (Rodentia: Octodontidae)
Authors: Castro Dolores del Carmen , Cicchino Armando
Published: November 2009

The species Phtheiropoios centralissp.nov. is described and illustrated from specimens collected on an undescribed species of Ctenomys from Rio Quinto, central Córdoba Province, Argentina. Diagnostic features for the new species include proportion of the male forficula, male external genitalia, and counts of setae and body measurements in both sexes. Its morphological affinities with other species and a key to males of all species of the genus Phtheiropoios known to parasitize rodents of the genus Ctenomys are included.
Bumble bee (Hymenoptera: Apidae) activity and loss in commercial tomato greenhouses
Authors: Morandin L.A. , Laverty T.M. , Kevan P.G. , Khosla S. , Shipp L.
Published: November 2009

Activity of bumble bees,Bombus impatiensCresson, was examined in commercial tomato,Lycopersicon esculentumMill. (Solanaceae), greenhouses in relation to greenhouse covering type, solar radiation, greenhouse temperature and humidity. Bumble bee activity was measured by photodiode monitors inserted into the entrance of the colonies. Colony sizes were monitored as an indicator of bee loss through gutter ventilation systems in relation to covering. Activity monitors were found to be a good predictor of actual bumble bee entrances and exits (r2= 0.85). Bumble bee activity was 94.0% greater under the ultravioltet (UV)-transmitting covering than under ones that transmitted less UV light. No relationship was found between bee activity and the amount of solar radiation or internal greenhouse humidity. Bee activity was weakly positively correlated with internal greenhouse temperature (r2= 0.18). Bee activity was not different during three periods of the day: morning, midday, and evening. The mean ± SE colony size under the UV-transmitting covering was 86.0 ± 2 bees per colony after 10 days within the greenhouses, compared with 36.4 ± 5.8 bees per colony under the other three types of covering. Our results suggest that bee activity is greatest and bee loss through gutter ventilation systems lowest in greenhouses made with coverings that transmit high levels of UV light.
New species of Aphthona (Coleoptera: Chrysomelidae: Alticinae) and key to Iberian species of Aphthona hammarstroemi group
Authors: Baselga Andrés , Novoa Francisco
Published: November 2009

Aphthona sandraesp.nov. is described from specimens collected on Euphorbia polygalifolia Boiss. et Reuter (Euphorbiaceae) in Galicia, Spain. Its relationship with Aphthona ovata Foudras and the Aphthona hammarstroemi Jacobson group of species is established. A key to the species of this group occurring in the Iberian peninsula is provided. Aphthona herbigrada (Curtis) and Aphthona espagnoli Kral, previously not belonging to any group, are here considered belonging to the A. hammarstroemi group.
Analysis of some historically unfamiliar Canadian mayflies (Ephemeroptera)
Authors: Jacobus Luke M. , McCafferty W.P.
Published: November 2009

Twelve historically unfamiliar Ephemeroptera species described from Canada over 65 years ago were studied. Diagnostic characters are given that validateAcerpenna akataleptos(McDunnough) (Baetidae), whereas certain larval specimens of the genusAcerpennaWaltz and McCafferty cannot yet be associated with any species.Cinygmula confusa(McDunnough, 1924),syn.nov., (Heptageniidae) is shown to be a junior synonym ofCinygmula par(Eaton, 1885), andSerratella serratoides(McDunnough, 1931),syn.nov., (Ephemerellidae) is shown to be a junior synonym ofSerratella molita(McDunnough, 1930). New distribution records are given forIronodes flavipennisTraver (Heptageniidae),Cinygmula gartrelliMcDunnough,Heptagenia adaequataMcDunnough (Heptageniidae), andSiphlonurus autumnalisMcDunnough (Siphlonuridae), including the first substantiated records for the latter three from the United States. A first larval description ofS.autumnalisis provided.Ephemerella fraterculaMcDunnough (Ephemerellidae) is apparently rare, but its previously doubtful North Carolina record is confirmed. All larvae previously reported asNeoephemera bicolorMcDunnough (Neoephemeridae) cannot be placed to any nominal species.Parameletus croesus(McDunnough) (Siphlonuridae),Plauditus rubrolateralis(McDunnough) (Baetidae), andRhithrogena gaspeensisMcDunnough (Heptageniidae) are distinctive species but are known from few records.
Detecting the titer in forest soils of spores of the gypsy moth (Lepidoptera: Lymantriidae) fungal pathogen, Entomophaga maimaiga (Zygomycetes: Entomophthorales)
Authors: Weseloh Ronald M. , Andreadis Theodore G.
Published: November 2009

Bioassays and direct counts were used to assess the abundance of resting spores of the gypsy moth, Lymantria dispar (L.), fungal pathogen, Entomophaga maimaiga Humber, Shimazu and Soper in forest soils. Resting spores in soil collected in October, January, and March and held under refrigeration germinated as readily as spores collected in April, but those collected in April germinated faster. Bioassays of resting spores in soils from different sites in Connecticut were directly related to results obtained from physically counting spores in the soil, and weakly correlated with a previously developed forest-based bioassay. The number of resting spores in a site was inversely related to the number of years since the site had last been defoliated by the gypsy moth, resulting in an implied maximum viability of resting spores of about 10 years. This maximum longevity was similar to a direct measure of long-term resting-spore viability. The study implies that resting-spore load in the soil may be an important determinant of the ability of the pathogen to control the gypsy moth.
Sampling range and range of attraction ofDendroctonus pseudotsugaepheromone-baited traps
Authors: Dodds Kevin J. , Ross Darrell W.
Published: November 2009

Two mark–recapture experiments and a trap interference experiment were conducted to determine the sampling range and range of attraction, respectively, ofDendroctonus pseudotsugaeHopkins (Coleoptera: Scolytidae) pheromone-baited traps in northern Idaho. To determine the sampling range, either live beetles or logs containing brood were marked with one of four colors of fluorescent powder. Colored beetles or logs were placed along transects oriented away from a central pheromone-baited trap at distances of 50, 100, 200, and 300 m. A release distance of 400 m was added to one mark–recapture experiment during the 2nd year. To determine the range of attraction, a trap interference study was conducted. For this experiment, groups of three traps were oriented in equilateral triangles with distances of 50, 100, 200, and 300 m between the three traps. Distances between traps were changed daily to allow for adequate replication. Mark–recapture studies indicated that mostD.pseudotsugaewere recaptured from distances less than or equal to 200 m from the pheromone-baited trap. On average, 95% of beetles recaptured were males. Results of the trap interference experiment provided no insight into the range of attraction ofD.pseudotsugaepheromones. Natural resource managers should attempt to place pheromone-baited suppression traps within 200 m of targetD.pseudotsugaepopulations. Also, to minimize undesirable beetle-caused tree mortality, traps should be placed as far as possible from live trees that managers wish to protect.
Orientation response of Pacific coast wireworm (Coleoptera: Elateridae) to food baits in laboratory and effectiveness of baits in field
Authors: Horton David R. , Landolt Peter J.
Published: November 2009

Assays were done in the laboratory and field to monitor the response of Pacific coast wireworm,Limonius canusLeConte, to food baits. A glass-plate assay was used in laboratory trials to study movement of wireworm larvae through soil in response to several food baits, including germinating seeds of grains, rolled oats [Avenu sauvaL. (Poaceae)], carrot [Daucus carotaL. (Umbelliferae)], and potato [Solanum tuberosumL. (Solanaceae)]. Studies were also done with these baits to determine effectiveness under field conditions. In both laboratory and field trials, germinating seed of wheat [Triticum aestivumL. (Poaceae)] and barley [Hordeum vulgareL. (Poaceae)] ranked higher in response by larvae than the remaining food baits. In the glass-plate assays, 65–70% of wireworms contacted the wheat or barley seed baits within a 2-h assay period. Corn [Zea maysL. (Poaceae)] seed and sliced carrot were also effective, with 60% of larvae contacting the baits. Rice [Oryza sativaL. (Poaceae)], rye [Secale cerealeL. (Poaceae)], and potato were contacted by 30–45% of larvae. In the majority of assays, contact with the bait occurred within 30 min of the start of the assay. Trail lengths varied substantially among larvae (0–70 cm). The field studies showed that all food baits captured more wireworms than unbaited traps. A second assay conducted in the laboratory showed that moistened rolled oats were contacted with a higher probability if oats were aged 72 h following wetting (51% of larvae contacted the bait) than oats used immediately following wetting (28% of larvae). Field trials using baits composed of different volumes of rolled oats showed little evidence of a dose response in capture rates ofL.canus, although all baits captured more wireworms than unbaited traps. These studies showed thatL.canusis attracted to food baits in both laboratory and field trials, and that baits may prove useful to monitor populations of this pest in the field.
Release of Osmia excavata and Osmia jacoti (Hymenoptera: Megachilidae) for apple pollination
Authors: Wei Shu-Ge , Wang Ren , Smirle Michael J. , Xu Huan-Li
Published: November 2009

Two species of bees native to China, Osmia excavata Alfken and Osmia jacoti Cockerell, were released in 1991–1993 to observe life-history characteristics and assess pollination efficiency. Osmia excavata successfully established in both coastal (Shandong Province) and interior (Hebei Province) habitats, whereas O. jacoti was only able to establish in the coastal habitat. Sex ratios (female:male) ranged from 1:1.05 for O. jacoti to 1:2.46 for O. excavata. Apple, Malus domestica Borkh (Rosaceae), pollination was enhanced following the release of either species in orchards in Shandong. Fruit diameter increased following the release of either Osmia species in 'Red Delicious' blocks compared with control blocks where no pollination treatment was applied. The number of seeds per fruit was also increased relative to controls, and the percentage of asymmetrical fruit decreased. Release of O. excavata produced the best results for this cultivar. For 'Ralls Janet', the number of seeds per fruit increased following the release of either species and the percentage of asymmetrical apples decreased. Effects on fruit diameter were confounded by poor cultural practices (i.e., lack of adequate fruit thinning) in these 'Ralls Janet' blocks. Fruit set increased relative to controls following release of either Osmia species for both apple cultivars. Release of O. excavata also produced higher fruit set relative to blocks that received hand pollination treatment; release of O. jacoti was better than hand pollination only for 'Red Delicious'. Observations on the behaviour of individuals showed that O. excavata averaged 49.6 foraging trips per day and set an estimated 3108 fruit on 'Ralls Janet'; O. jacoti made fewer foraging trips (average of 31.2) per day and set 1831 fruit. Both species were more efficient pollinators than Apis mellifera. Osmia excavata would appear to be a better candidate for commercial apple pollination than O. jacoti under conditions similar to those in this study.