Variation in leaf quality includes differences in both primary nutrients and secondary metabolites. Both of these factors can influence the feeding preference and resulting performance of herbivores in ways that are difficult to disentangle when comparing foliage from different sources. Our study was designed to assess the effects of the ratio of the primary nutrients in host-tree foliage, protein and sugar, on the performance and feeding behaviour of the forest tent caterpillar (Malacosoma disstria Hübner (Lepidoptera: Lasiocampidae)). Fourth-stadium larvae were fed trembling aspen leaves (Populus tremuloides Michx (Salicaceae)) supplemented with casein, sucrose, or buffer only (control). No differences in taste responses to the three leaf types were detected. In a cafeteria situation, feeding behaviour over the short term was largely determined by the use of pheromone trails and hence depended on which leaf was contacted first. Over the longer term, caterpillars fed most on the control leaf and the sugar-supplemented leaf and discriminated against the protein-supplemented leaf. Sugar supplementation increased survivorship relative to the control treatment but slowed development and did not affect growth; protein supplementation decreased growth. These findings are consistent with past research comparing forest tent caterpillar performance and feeding preference on different host plants.

The apple brown bug, Atractotomus mali (Meyer), is an economic pest of apple in the Annapolis Valley of Nova Scotia (Rogers 1990). Feeding on developing fruit of sensitive apple varieties induces persistent corky scar tissue that reduces the quality of affected fruit. Forty-five percent of Annapolis Valley apple orchards monitored in 1992 required chemical insecticide applications to control the pest complex of A. mali and the mullein bug, Campylomma verbasci (Meyer) (Craig 1992).

Female-produced sex pheromones occur in several mirid species, including the mullein bug (Smith et al. 1991) and Lygocoris communis (Knight) (Boivin and Stewart 1982). The sex pheromone of C. verbasci has been identified as a 16: 1 blend of butyl butyrate and crotyl butyrate (Smith et al. 1991). Our objective was to determine if a sex pheromone occurs in A. mali.

Adults of Trisetacus chamaecypari n. sp., and female adults of T. thujivagrans n. sp. are described, and species of Trisetacus associated with Cupressaceae and Taxodiaceae are discussed and keyed. An original diagnosis of the genus Trisetacus is included.

A national survey shows that the merchant grain beetle, Oryzaephilus mercator Fauvel, has been present in Canada since at least 1925 and that it has become firmly established as a household pest of processed cereal products preferably of high oil content, but has not been reported from stored grain. A related species, the saw-toothed grain beetle, Oryzaephilus surinamensis (L.), infests both stored grain and processed cereal products. Illustrations are provided to show the morphological characters by which the two species may be recognized and separated.

Since 1925 the lecanium scale Eulecanium coryli (L) has been one of the most destructive insects in the coast region of British Columbia. It was introduced accidentally from Europe about 1913. A great variety of hosts are attacked, the chief of these, in order of preference, being: alder, horse-chest-nut, maples of several species, hawthorn, mountain ash, laurel, elm and garden roses; a few scales are often to be found on species of Rubus, Populus, Betula and Salix.

The aquatic plants Utricularia minor L., Lemna minor L., and Elodea canadensis Rich. in Michx. were tested for their effects on the colonization of artificial ponds by mosquitoes and their predators. During the 11 weeks of sampling there were significantly fewer mosquito eggs, and hence mosquito larvae, in the plant-filled ponds than in plantless control ponds, and more predators in the Utricularia and Elodea ponds than in the plantless and Lemna ponds.

Aside from M. acerbus (Jordan), which is apparently a breeding parasite of Tamias striatus (L.), a chipmunk, the holarctic genus Megabothris Jordan 1933 appears to be truly associated with the Microtinae, some of the species showing special affinities for particular species of these mice, others infesting several species, or even genera, within a geographical region.

The nearctic Megabothris asio (Baker) favours the common meadow vole, Microtus pennsylvanicus (Ord), and occurs throughout most of the range of that mouse. The writer recognizes two valid subspecies, M. asio asio, which is restricted to eastern North America, and M. asio megacolpus (Jordan), of western North America. The nominate race ranges from Labrador to Delaware. M. asio megacolpus (=M. asio orectus Jord.) ranges from western Quebec, western Ontario, and Michigan westward to the Coast Range, and from California north at least to the 60th parallel.

Nearctic horse flies usually identified as Tabanus (Hybomitra) frontalis Walker or septentrionalis Loew, or simply as T. frontalis septentrionalis complex, have puzzled taxonomists for more than a century. These tabanids (Figs. 1-3), which are among the most widely distributed, most abundant and most troublesome biters of animals and man in North America, are extremely variable, especiallly in color and size. Those who have studied the group have widely different views concerning the taxonomic significance of the variations observed. To date, five nominal species (excluding T. opacus Coq.) have been described from small samples of populations of the group from various parts of Canada, i.e., frontalis and incisus Wlk. (Nova Scotia), septentrionalis Loew and labradorensis Enderlein (Labrador), and canadensis Curran (central Manitoba).

This list is a record of insects which have been found in or on Douglas fir in the northern Rocky Mountain region by personnel of the Forest Insect Field Laboratory at Coeur d'Alene, Idaho. It comprises insects which feed upon the tree, as well as the parasites and associates of these insects. Of the 153 species listed, 102 were collected by the writer while making a study of the Douglas fir beetle (Dendroctonus pseudotsugae Hopk.). The remainder are listed in the laboratory records and were collected by J. C. Evenden, R. E. Balch, H. J. Rust, and D. DeLeon.

The female and male of Tarsonemus granarius n. sp. are described and illustrated. This mite occurs in granaries in Canada, Japan, and the British Isles. It feeds on, and perhaps disseminates, fungi that deteriorate grain stored for prolonged periods. Similarities and differences in the morphology and ecology of adults of this species and of T. fusarii Cooreman are discussed.

The effect of abamectin on the leafminer, Liromyza trifolii (Burgess), was investigated using topical applications, leaf dips, and repellency bioassays. Topical application of technical material in acetone to susceptible adult females provides an LD50 value of 0.404 ppm. Leaf-dip assays using abamectin formulated in water with third-instar larvae gave an LC50 value of 0.386 ppm. These data provide baseline information on the toxicity of this material to L. trifolii and are important in the development of resistance management programs. Adult female leaf miners were repelled from feeding and ovipositing on chrysanthemum plants treated with formulated abamectin up to 7 days after foliar application in choice and no-choice assays. The implications of these data in managing populations of L. trifolii are discussed.

Host preference of the pine shoot beetle, Tomicus piniperda (L.), was investigated in two laboratory choice test studies using red pine (Pinus resinosa Ait.) (Pinaceae), jack pine (Pinus banksiana Lamb.), and Scotch pine (Pinus sylvestris L.). Host preference of parent adult beetles was evaluated using freshly cut, similarly sized logs in a wind tunnel. Parent beetles colonized Scotch pine logs significantly more often when given a choice of Scotch pine and either red pine or jack pine logs, but did not show a preference when presented with red pine and jack pine logs. Host preference of progeny adults was tested in a laboratory bioassay using current-year pine shoots. Shoot-feeding progeny adults initiated tunnels in jack pine shoots significantly more often than in Scotch pine and red pine shoots, and preferred Scotch pine over red pine shoots. Shoots with diameters of 0.4–0.5 cm were attacked most frequently, regardless of species. Results suggest that the two North American pines are suitable hosts, but T. piniperda may be most likely to colonize Scotch pine, a European species. Efforts to detect or monitor T. piniperda populations in the Great Lakes and northeastern regions should focus on areas with abundant Scotch pine brood material. Progeny that emerge from brood material, however, may be as likely to shoot-feed in jack pine as in Scotch pine.

One of the most outstanding instances of the benefits to be derived from the importation of parasites of our injurious insects, be they of foreign or domestic origin, is to be found in a study of the Larch Sawfly situation in Canada, especially in Manitoba, during the past twenty years.

North American species of Agabus Leach of the elongatus-, zetterstedti-, and confinis-groups, as defined by Larson (1989), are revised. Study of character state distribution indicates that the elongatus- and zetterstedti-groups are clades within the confinis-group but the names are retained in this paper to maintain consistency. Twenty species belonging to this complex occur in North America, namely: elongatus-group with A. elongatus Gyllenhal and A. inexspectatus Nilsson; zetterstedti-group with A. zetterstedti Thomson; and the confinis-group with A. thomsoni (J. Sahlberg), A. moestus (Curtis), A. clypealis (Thomson), A. phaeopterus (Kirby), A. immaturus sp.nov. (Great Lakes and Maritime Provinces regions), A. canadensis Fall, A. audeni Wallis, A. mackenziensis sp.nov. (northwestern Canada), A. bicolor (Kirby), A. subfuscatus Sharp, A. discolor (Harris), A. approximate Fall, A. kootenai sp.nov. (southwestern Canada and northwestern United States), A. inscriptus (Crotch), A. smithi Brown, A. sasquatch sp.nov. (alpine areas of California and Nevada), and A. confinis (Gyllenhal). For each species the following information is provided: synonymy; description and illustration of taxonomically useful characters; notes on relationships, variation, distribution, and ecology; and a map of North American collection localities. A key to the North American species of the confinis-group is presented. Lectotypes are designated for A. subfuscatus Sharp, Gaurodytes inscriptus Crotch, G. ovoideus Crotch, and G. longulus LeConte.

Eight species and seven subspecies of costate Altica are described and illustrated. Lectotypes are designated for Altica alni Harris, A. ambiens LeConte, A. prasina LeConte, A. subplicata LeConte, and Graptodera plicipennis Mannerheim. A neotype is designated for Altica bimarginata Say. Two subspecies are recognized for A. ambiens, three for A. bimarginata, and two for A. prasina. Graptodera plicipennis is removed from synonymy and given a new subspecific status under Altica bimarginata, and A. populi Brown is given a new subspecific status under A. prasina. Altica latiplicata Blake is placed in synonymy with A. ambiens LeConte. Altica bimarginata labradorensis LeSage is described as a new subspecies of A. bimarginata. Keys are given for males and females, and data are provided on distribution, host plants, biology, parasites, predators, and economic importance of these species.

Temperature effects on development were studied for two Alberta populations of Ostrinia nubilalis (Hübner), from the South Saskatchewan River valley and the surrounding plains. Lower developmental thresholds for all life stages of both Alberta populations were determined by linear regression. Thresholds for the egg stage were significantly less for plains borers (9.5°C) than for valley borers (10.8°C), and about 2°C lower than for corn borers from the United States. Thresholds in Alberta populations for the 4th (15.3°C) and 5th (14.0°C, plains) instars, and for post-diapause pupation (12.8°C), were much higher than in populations from the United States. Higher temperature thresholds delay development in Alberta populations, thus reducing midsummer pupation. Valley populations developed significantly faster than plains populations during egg development, during the prepupal period of the 5th instar, and during post-diapause pupation. These results explain why valley populations have a partial second generation in some years.

A study was conducted to determine the effectiveness of a novel insect growth regulator (IGR) with juvenile hormone activity. Tests show the third instar to be the stage most sensitive to the regulator based on reduction of fecundity throughout inhibition of normal adult development. Effective control in most stages was for the first time brought about within the realm of economic feasibility. The IGR could be of value in future control of aphid populations.

Male gypsy moths (Lymantria dispar (L.)) have a superposition compound eye. Electroretinogram (ERG) responses indicate low sensitivity in the ultraviolet region, higher sensitivity from 480 to 590 nm, and essentially no sensitivity in the red region. The microspectrophotometric absorption spectrum of the visual screening pigments shows low absorption in the ultraviolet and red regions and high absorption from 400 to 600 nm. Screening pigments migrate in response to illumination during diurnal activity periods, so the eye acts in the photopic mode. Because these pigments are essentially transparent to ultraviolet wavelengths, the eye may be in effect acting simultaneously in the scotopic mode for these wavelengths.

Attacks by Scolytus ventralis on white fir were correlated both with periods of low precipitation and with medium to heavy infestations of true mistletoe. Trees were seldom attacked when the "running mean precipitation" was above 54 in. Attacks were significantly more frequent and were often a year or more earlier on trees with substantial amounts of mistletoe. Broods were seldom produced, however.Data suggest that heavy mistletoe infestation rendered trees more susceptible to beetle infestation, possibly by creating moisture stress in infected trees.