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Camptopeltesn. gen. is described for three new species: Camptopeltes atratumn. sp. (type species of the genus; type locality Cartago, Costa Rica); Camptopeltes citrinumn. sp. (type locality Yacambo, Venezuela); and Camptopeltes nubilatumn. sp. (type locality Aragua, Venezuela). Camptopeltes is distinguished from other oscinelline genera on the combination of a strongly convex scutum, a trapezoidal scutellum that is deflected dorsally relative to the scutum, a reduced flexure in wing vein CuA1, reduced cephalic bristling, reniform third antennal segment, and thin arista. Although its relationship to the rest of the Oscinellinae is unresolved, it may be closely related to the tribe Elachipterini.
A new species, Arthula biformis Oh and Lee sp.nov., belonging to the cryptine ichneumonid subtribe Sphecophagina Beirne is described from Korea. The new species is composed of two seasonal forms, overwintering and summer, distinguished by color and some morphological features. The overwintering form is much darker than the summer form. Keys to the genera of Sphecophagina and the known species of Arthula Cameron and photographs of diagnostic characters of both color forms of the new species are provided.
Introgression of cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae), resistance from Sinapis alba L. to susceptible Brassica napus L. (Brassicaceae) has produced genetic lines resistant to the weevil in replicated field trials. In the current study, weevil feeding and oviposition on S. alba and on resistant novel lines developed by crossing S. alba × B. napus were less frequent than on susceptible germplasm. Development times were greater and biomass was less when larvae were reared on resistant lines or S. alba. Oocyte development was faster in post-diapause springtime adult female weevils caged on susceptible plants than in those on a resistant line, S. alba, or an early-season food host, Thlaspi arvense L (Brassicaceae). Our results suggest that antixenosis resistance and antibiosis resistance are expressed by resistant lines. These results and previous chemical analyses of these lines also suggest that resistance is potentially influenced by attractive and (or) feedings-timulant effects of 2-phenylethyl glucosinolate and antifeedant or toxic effects of 1-methoxy-3-indolylmethyl glucosinolate.
Trap crops are a plausible control strategy for the wheat stem sawfly (WSS), Cephus cinctus Norton (Hymenoptera: Cephidae), especially in alternate wheat—fallow cropping systems. Identifying the most suitable winter wheat (Triticum aestivum L., Poaceae) cultivars is necessary to further improve the effectiveness of winter wheat trap crops. We compared cultivars suitable for cultivation in Montana to identify those that exhibit the greatest potential as trap crops. To accomplish this we used nine winter wheat cultivars to analyze plant characteristics that influence the oviposition behavior of the WSS: stem height, stem diameter, rate of plant development, and emission of the WSS attractant (Z)-3-hexenyl acetate. Data on sawfly-induced stem cutting collected from these cultivars in field nurseries were analyzed to evaluate the potential of each cultivar to attract sawflies. Based on these criteria, five cultivars with good potential as trap crops are ‘Norstar’, ‘Neeley’, ‘Morgan’, ‘Rampart’, and ‘BigSky’. More data from laboratory preference tests and detailed measurement of semiochemical production from these cultivars are required for selecting optimal cultivars for trap-cropping.
To characterize time of spring emergence following post-diapause development, Delia radicum (L.) (Diptera: Anthomyiidae) from Saskatchewan, Manitoba, and southwestern Ontario were collected in fall, maintained over winter at 1 °C, then transferred to higher constant temperatures until adult emergence. At each location there were “early” and “late” phenotypes. Truncated normal models of temperature dependency of development rate were fitted for each phenotype from each location. We provide the first evidence of geographic variation in the criteria separating these phenotypes. Separation criteria and models for early and late phenotypes at the two prairie locations, approximately 700 km apart, were indistinguishable, but differed from those for Ontario. Prairie phenotypes developed more slowly than Ontario phenotypes, and more prairie individuals were of the late phenotype. Poor synchronization of spring emergence could impair predation of D. radicum eggs by adult Aleochara bilineata Gyllenhal (Coleoptera: Staphylinidae). Aleochara bilineata from Manitoba were reared and development rates modelled as for D. radicum. Models of development rates for the two species, when combined with simulated soil temperatures for two prairie locations, suggest that emergence of adult A. bilineata is well synchronized with availability of D. radicum eggs in prairie canola.
We studied Culex pipiens L. in the Niagara Region of Ontario, Canada, to establish whether or not these mosquitoes are attracted to hosts other than birds at different elevations or as the season progresses. Guinea-pigs and chickens were used as representative mammalian and avian hosts, respectively. Bait animals were placed next to modified CDC miniature light traps (no light and no CO2) hung 1.5 or 5 m above ground in a Niagara woodlot. The season was divided into three 6-week periods (early, middle, and late). Significantly more C. pipiens were captured at the 5 m than at the 1.5 m elevation. In general, chicken-baited traps were preferred over control and guinea-pig-baited traps, with one important exception: there was no significant difference among traps during the late period at 1.5 m elevation. The potential role of C. pipiens as a bridging vector of West Nile virus to humans is discussed.
We describe the calling posture of the brown spruce longhorn beetle, Tetropium fuscum (F.), and demonstrate, using solid-phase micro-extraction and gas chromatography — mass spectrometry, that this posture is positively correlated with the release of fuscumol, a male-produced long-range pheromone. The posture is observed only in males and is characterized by an extension of the legs that raises the body entirely off the substrate at an angle of approximately 10°, with the posterior end higher than the head. Characterization of the calling posture is a useful diagnostic tool for future research on the reproductive biology of T. fuscum, since a simple visual assessment can be used instead of chemical analysis to determine when males are emitting fuscumol. In addition, we demonstrate that the presence of conspecific males stimulates calling behaviour in T. fuscum. This study contributes much-needed data on the biology and mating behavior of this invasive wood-boring species.
A white spruce, Picea glauca (Moench) Voss (Pinaceae), plantation in southern Quebec was found to contain two distinct types of trees, the first resistant and the second susceptible to attack by spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae). To identify the mechanisms of white spruce resistance to spruce budworm, we studied the role of epicuticular waxes, comparing (i) the foliar chemistry of susceptible and resistant trees and (ii) the feeding pattern of larvae at first contact with the foliage. Needles collected from resistant trees contained concentrations of the monoterpenes α-pinene and myrcene that were 307% and 476%, respectively, above those found in needles collected from susceptible trees. Although there were no significant differences in probing behaviour, significantly fewer larvae transitioned from probing to feeding on resistant needles; this led to fewer feeding bouts as well as a significantly shorter first meal. Removal of waxes increased the number of individuals transitioning from probing to feeding on resistant needles; this led to more feeding bouts. Our results demonstrate that monoterpenes influence the pattern of feeding of spruce budworm larvae as well as playing an important role in white spruce resistance.
Honey bees, Apis mellifera (L.) (Hymenoptera: Apidae), are parasitized by the microsporidians Nosema apis (Zander) and Nosema ceranae (Fries). Molecular techniques are commonly used to differentiate between these parasites because light microscopy is inadequate. Our objectives were to (i) adapt the previously published duplex polymerase chain reaction (PCR) targeting the 16S rRNA gene of N. apis (321APIS-FOR, 321APIS-REV) and N. ceranae (218MITOC-FOR, 218MITOC-REV) using qualitative real-time PCR assay with SYBR® Green I dye (R-T PCR) and DNA melting-curve analysis, and (ii) determine whether the two Nosema species can be detected simultaneously in honey bees. Total spore counts and purified total genomic DNA were obtained from 37 bee samples (19 individual workers and 18 pooled samples of 15 workers) collected in Nova Scotia, Prince Edward Island, and Newfoundland, Canada. Overall, the prevalence of Nosema species was 86.5% (32/37 samples of bee DNA), based on conventional PCR and the optimized R-T PCR assay. The melting-curve analysis showed three groups of curve profiles that could determine the prevalence of N. apis, N ceranae, and co-infection (21.9%, 56.2%, and 21.9%, respectively). The duplex R-T PCR assay was efficient, specific, and more sensitive than duplex conventional PCR because co-infection was identified in 5.4% (n = 2) more samples. Sequencing of R-T PCR products confirmed the results of the melting-curve analysis. Duplex R-T PCR with melting-curve analysis is a sensitive and rapid method of detecting N. apis, N. ceranae, and co-infection in honey bees.
The plum curculio, Conotrachelus nenuphar (Herbst), is a serious pest of stone and pome fruits (Rosaceae) in eastern North America. We recorded captures of adult plum curculios in the field and measured electroantennogram (EAG) activity in the laboratory associated with cultivars of four hosts, ‘Formosa’ Japanese plum (Prunus salicina Lindl.), ‘Stanley’ European plum (P. domestica L.), ‘Empire’ apple (Malus domestica Borkh.), and ‘Loring’ peach (P. persica (L.) Batsch) (Rosaceae) to determine whether hosts that may be attractive to the plum curculio under field conditions also elicit positive EAG responses. Trap captures of adults on ‘Formosa’ plum were significantly greater than on any other host, and corresponding headspace extracts also produced strong EAG responses throughout the active season. ‘Stanley’ plum and ‘Loring’ peach, the other stone-fruit hosts included in the study, elicited strong EAG responses throughout the season, although trap captures associated with these hosts were generally not as high as for ‘Formosa’ plum. Throughout the season, trap captures of adults were significantly lower for ‘Empire’ apple than for ‘Formosa’ plum, and EAG responses were much lower than for all stone-fruit hosts. Our results indicate that volatiles from ‘Formosa’ plum likely contain uniquecompounds or are comprised of ratios of stimulating compounds that make it much more attractive to plum curculio in the field.
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