The taxonomy of the genus Ceramida Baraud, 1987, some species of which are severe pests, is considered difficult because of a lack of reliable diagnostic characters. We propose a new approach to the taxonomy of this genus by studying the efficacy of morphometric characters for species discrimination employing multivariate analysis. All members of the genus were included in the analysis. The seven morphometric characters considered were all found to be diagnostic at me species level: width of clypeus at base and at mid-length, and length of clypeus, full body, antennal club and stem, and apical segment of maxillary palp. The most informative character is the length of the antennal club relative to body size. This character divides the genus into three morphological groups. The ratios traditionally employed in the taxonomy of this genus cannot be used as discrete characters because there are no gaps in their range of variation. Our discriminant analysis produced several classification functions that serve as a new taxonomic tool to distinguish between morphologically similar species. Eleven species are recognized within the genus and eight new synonymies are proposed.

Pissodes punctatussp.nov. and Pissodes yunnanensissp.nov., reared from Pinus armandii Franchet and Pinus yunnanensis Franchet (Pinaceae) in southwestern China, are described and illustrated. Both species attack the upper portions of the stems of young trees, and larvae feed in the phloem and cambium.

Dissochaetus cubensissp.nov. is described from Cuba. New forest and cave records are given for the previously poorly known species Proptomaphaginus apodemus Szymczakowski and Proptomaphaginus darlingtoni (Jeannel) from Cuba and Proptomaphaginus hispaniolensis Peck from the Dominican Republic on the West Indian island of Hispaniola.

Collembola of 12 sugar maple forests of southern Quebec were surveyed through pit-light trapping and soil core extraction. These two sampling techniques were highly complementary, as pit-light traps are more efficient for sampling epigaeic species while soil core extractions are more efficient for hypogaeic species. A total of 108 species representing 38 genera and seven families was collected. Nine genera and 67 species are new records for the province of Quebec and 12 species are new records for Canada. The distribution of species among the different sites is summarized and taxonomic remarks are provided for 20 problematic species. A low percentage of the Quebec collembolan fauna is shared with Ontario and Newfoundland, which probably reflects an incomplete inventory of the fauna rather than highly different regional patterns in collembolan communities. The use of these two complementary sampling techniques is suggested to improve the inventory of Collembola in future research.

Recent damage to sugar maple, Acer saccharurn Marsh., by pear thnps, Taeniothrips inconsequens, in the northeast of the United States and adjacent parts of Canada has led to much research on this pest (Teulon et al. 1993; Teulon and Cameron 1996; Parker and Skinner 1997). A detailed description of the univoltine pear thrips' life history is reported in Teulon et al. (1998). Although T: inconsequens is the dominant species in sugar maple, other thrips may also be important as herbivores, detritivores, or predators and need to be taken into account in sampling or monitoring programmes. This article describes the diversity of thrips in a sugar maple plantation in central Pennsylvania, United States.

The within-tree scale dynamics of mass attack by the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, on its host were investigated and quantified. Seven similarly sized Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco (Pinaceae), infested as part of several pheromone-induced infestations, were monitored over an entire attack season. Ninety percent of the attacks on mass-attacked trees occurred within 3 weeks of colonization; the remaining 10% occurred gradually over the remaining 7 weeks of the attack season. Vertical attack distribution followed a Gaussian form that shifted upwards on the bole with increasing attack density. The change in attack pattern associated with increasing attack density was investigated for the central vertical portion of the bole, where most attacks occurred, and where the vertical pattern was least variable. At low density, attacks were randomly distributed. As density increased, the distance between attacks decreased, eventually resulting in a uniform distribution.

Using alternating patches of weeds and crop [broccoli, Brassica oleracea (L.) (Brassicaceae)], vegetation composition and the spatial scale at which the vegetation was fragmented were manipulated in a factorial design field experiment. The effects of these manipulations were different for two common agroecosystem predators sampled. Sevenspotted lady beetles, Coccinella septempunctata (L.), were unaffected by vegetation-composition treatments but responded strongly to fragmentation-scale manipulations. The beetle Pterostichus melanarius (Illiger) was unaffected by both fragmentation-scale and vegetation-composition manipulations. These findings highlight the challenge of developing a predictive theory of the effects of vegetation diversification on assemblages of predators in agroecosystems.

Larvae of the hemlock looper, Lambdina fiscellaria fiscellaria (Guenée) (Lepidoptere: Geometridae), consume both new and old foliage within the crowns of their host, balsam fir, Abies balsamea (L.) Miller (Pinaceae), despite the poor nutritional quality generally ascribed to old tissues. Laboratory studies evaluated whether the consumption of old foliage by hemlock looper larvae could be an adaptation to the relative paucity of new versus old foliage, and to the limited temporal window during which young foliage remains high in nutritional quality. Access to new foliage was critical to hemlock looper survival; 55% of larvae fed an exclusive diet of new foliage survived, whereas only 5% and 0% of larvae fed exclusively 1-or 2-year-old foliage survived, respectively. Moreover, larvae reared on branches in synchrony with bud flush were more than twice as likely to survive than those whose emergence was delayed by 2 weeks. Despite the reliance by the hemlock looper upon new foliage for survival, larvae given access to both new and old foliage survived better and were heavier than those restricted to new foliage. By incorporating older foliage into their diet, the hemlock looper can circumvent the limited availability of new foliage, thereby gaining access to more abundant tissues.

Variation in bark beetle attack following spacing of mature lodgepole pine stands in the East Kootenays of British Columbia was analyzed in relation to stand location (site), spacing treatment, and harvesting injury. Observations were made on three sites, each having three treatments: 4 × 4 m spacing, 5 × 5 m spacing, and untreated control. There was no statistically significant difference in the numbers of attacked trees among sites or treatments. However, in the spaced plots 94.3% of the attacked trees sustained harvesting injury or were located adjacent to skid trails. Dendroctonus valens LeConte was the dominant species attacking trees on the two drier sites, and Dendroctonus murrayanae Hopkins was the dominant species on the third site. There was no statistically significant variation in the percentage of attacked stumps among sites or spacing treatments. On average, 80.7% of the stumps were attacked; attacked stumps had larger diameters than unattacked stumps. Thirteen species of bark beetles were found attacking stumps. Hylurgops porosus LeConte was the most numerous species at all three sites. Based on the fit of the Michaelis–Menten equations to species accumulation curves, an estimated 76–90% of the number of species attacking stumps at the three sites were observed in bark samples. Margalef’s index of diversity for the two drier sites (Cranbrook = 1.15, Parson = 1.13) was nearly identical and higher than at the moist site (Elkford = 0.89). Pairs of sites had five to six species in common, and the Sorensen coefficient of similarity ranged from 0.52 to 0.71, indicating moderate similarity in species composition. The abundance versus species rank relationship was fitted by three models: the MacArthur broken stick model, the geometric series, and the Zeta distribution. The latter gave good fit to data from two sites, but none of the fitted models gave satisfactory fit to data from the third site, mainly because of the high abundance of the second ranked species (Orthotomicus caelatus Eichhoff). Our results indicated that stand characteristics affected species assemblages and abundances of bark beetle species that attacked stumps. Management practices that minimize injury to trees during the spacing operations are emphasized to reduce attack by bark beetles.

The research objective of this study was to develop a pheromone-based detection system for the nun moth, Lymantria monacha (Linnaeus), an important defoliator of spruce, Picea A. Dietrich, and pine, Pinus Linnaeus (Pinaceae), forests in central Europe. In northeastern Germany, comparative analyses of rubber- and polyurethane-based dispensers impregnated with a 20:20:1 blend of (±)-disparlure (cis-7,8-epoxy-2-methyloctadecane), (±)-monachalure (cis-7,8-epoxy-octadecane), and 2-methyl-Z7-octadecene revealed that polyurethane-based dispensers afforded higher captures of male L. monacha. Species specificity and optimal dose of the pheromone dispenser were tested in deciduous rather than coniferous forests in central Europe to better reflect nonhabitat settings, such as North American ports, in which detection surveys would be conducted. Baiting Unitraps with 2, 20, 200, or 2000 μg [based on (±)-disparlure] of the L. monacha volatile blend resulted in increasing, species-specific captures of male L. monacha with increasing volatile dose. (±)-Disparlure, previously used for detection of L. monacha, tested at the same four doses indiscriminately attracted male L. monacha and male Lymantria dispar (Linnaeus). Polyurethane-based dispensers loaded with at least 200 μg of the L. monacha volatile blend are recommended for sensitive detection surveys of L. monacha in North America.

We examined the factors that might influence ovary development in worker honey bees, Apis mellifera L. Queenless workers at different ages (≤ 12 h, and 4, 8, and 21 d) were tested in cages for ovarian development. Newly emerged, 4- and 8-d-old, and 21-d-old workers had medium-, large-, and small-sized ovaries, respectively, suggesting that of the worker ages tested only 4- and 8-d-old workers are likely to become egg layers in a queenless colony. Also, we compared ovarian development of newly emerged workers that were caged for 14 d and allowed to consume either pollen or royal jelly to that of another group of workers similarly caged but screened so that they could only obtain food via trophallaxis from young bees. Ovaries of newly emerged workers that received food from young bees were as well developed as those of newly emerged workers allowed to take pollen or royal jelly directly. Screened workers also had lower but still elevated vitellogenin levels compared with bees having direct access to food. These results indicate that nurse-age bees functioning as pollen-digesting units affect the ovarian development of other workers and to a lesser extent vitellogenesis via food exchange. We compared the influence of group sizes of 25, 125, and 600 bees per cage on ovarian development for 14 d. The two groups of 25 and 125 bees had similar mean ovary scores, and higher scores than a group of 600 bees. Our findings suggest that nurse-age bees could play an important role in mediating worker fertility via trophallaxis, possibly by differentiating worker dominance status, and generally only young workers become fertile when a queen is lost in a colony. Vitellogenin is a more sensitive parameter to measure bee fertility, and might be a useful tool to further explore ovary development and egg laying in worker social insects. We recommend measuring haemolymph vitellogenin titres and (or) oocyte length of workers in a group of 25 bees per cage, supplied with 50% royal jelly in honey as a standard method to assess honey bee worker fertility in future experiments.