Studies on population increase of the alfalfa leafcutter bee (Megachile rotundata Fabr.) were conducted in northern areas of Alberta and British Columbia (lat. 55°N. to 58°30′N.). Polyethylene shelters with one side open, placed over the domiciles, raised domicile daytime temperatures by 4°–10 °C, increased the duration of activity and the pollinating range of the bees, and resulted in an increased number of cocoons. Population increase was 2–5 times greater when hives and shelters faced south than when they faced east or west. Within a shelter bees also preferred hives with southern exposure. Movement of domiciles in mid-season for distances of 150 m or more caused a reduction in bee populations. Bees preferred wood to polystrene nesting material, old to new material, and surface stained material with patterns to unstained material. Severe mould development in polystrene nesting material affected development of larvae and emergence of pupae. Since population increase of M. rotundata, by utilization of polyethylene shelters and by proper directional orientation, is successful, re-establishment of a major alfalfa industry in northwestern Canada is now possible.

The oribatid mite family Mycobatidae is represented in America north of Mexico by the eight genera, Cyrtozetes Behan-Pelletier, Ceresella Pavlitshenko, Guatemalozetes Mahunka, Minunthozetes Hull, Mycobates Hull, Pelopsis Hall, Punctoribates Berlese, and Zachvatkinibates Shaldybina. Species occur in forests, grasslands, and arctic soils, in canopy habitats, and in the marine and freshwater littoral zone. Three new mycobatid species from North America are described: Ceresella reevesisp. nov. from forest habitats of western North America, Cyrtozetes lindoaesp. nov. from canopy habitats of western Canada, and Punctoribates weigmannisp. nov. from forest litter in eastern North America. The descriptions of Pelopsis bifurcatus (Ewing) and Punctoribates punctum (C.L. Koch) are expanded based on specimens from North America. Punctoribates palustris (Banks) is redescribed based on specimens from throughout North America. Punctoribates armipes (Banks) is considered a junior subjective synonym of P. palustris (Banks). New distribution records are given for Guatemalozetes danos Behan-Pelletier and Ryabinin and Minunthozetes semirufus (Koch). Diagnoses are given for each genus discussed, and keys are provided to the eight genera of Mycobatidae of North America and to species of Cyrtozetes and Punctoribates, genera not recently revised.

The relation of host density to reproduction of the chalcid parasite Dahlbominus fuscipennis (Zett.) was examined in a previous study (Burnett, 1954). When the parasite searched in a naturally varying physical environment for hosts–cocoons of sawflies that attack conifers–distributed over plots on a grass lawn, the influence of host density on parasitism was similar to that obtained in laboratory experiments. As the irregularities of the meteorological factors did not appreciably alter the relation of parasitism to host density it was of interest to determine whether the additional discontinuities of a natural environment would.

Short-term interactions of the polyphagous tachinid Winthemia rufopicta (Big.) with its hosts, especially Heliothis zea (Boddie) and H. virescens (Fab.), are considered.

Within a given host species, interacting factors fall into three groups: (1) factors that have little influence on parasite oviposition, or cause little parasite mortality (host responses to ovipositing parasites, previous parasitism, firmness of attachment of eggs and, in the populations studied here, direct competition with other insect parasites); (2) factors that may account for significant limitation of oviposition (habitat, diel activity, and seasonal occurrence of a given host, and species preference of the parasite) or that cause significant parasite mortality (destruction by the host and other mortality of hatching maggots, which in turn depends partly on the position of eggs on the host): and (3) factors that can vary widely in a given host species and are therefore of great potential importance. These are: (a) host feeding behaviour—initial parasitism of H. zea, for example, varies from negligible levels for larvae concealed in corn ears to sometimes very high levels for larvae feeding openly on tobacco leaves; (b) host size—smaller larvae (especially penultimate compared with final instars) receive fewer ovipositions, and fewer eggs per oviposition; (c) host moulting—surface-deposited eggs are lost if the host moults before they hatch, but the rate of moulting varies with instar and foodplant, and interacts differently with parasite egg incubation times at different temperatures (most eggs are lost except in final instars); (d) intraspecific competition—depends on parasite and host densities, but reaches the highest levels in the fall; (e) competition with host pathogens—parasites may be killed during development if the host dies from pathogens.

For different hosts, family, size, surface quality, and spatial and temporal availability are known to have divergent influences on the levels of parasitism, but many other interactions are probably important.

The interpretation of records of total or of successful parasitism in host samples is considered—behavioural, developmental, and numerical interactions may make conclusions drawn from such records unreliable. In particular, levels of parasitism may change very rapidly as host or parasite populations develop; laboratory rearing may distort recorded levels of successful parasitism; and the proportion of attacked hosts that produce parasites, and the number of parasites produced by each host, normally varies directly with the number of eggs per host even when this is large.

This paper presents the results of quantitative studies designed to determine, under field conditions, the influence of weather on the activity and development of adults and larvae of the white pine weevil, Pissodes strobi (Peck). The investigation forms part of a general program to determine the physical and biological requirements of the insect, with the ultimate objective of assessing the role of the environmental complex in limiting weevil development and survival to particular stand conditions. The problem arose when it became apparent that this information was pertinent to studies designed to determine the effectiveness of applied silviculture in the control of the insect. In addition, it provided the opportunity of assessing the effectiveness of applying quantitative bioclimatic methods in the field.

The predacious mite, Melichares dentriticus (Berlese), has been mass-cultured (Burnett, 1960) for the past few years at this laboratory on populations of Tyrophagus putrescentiae (Schrank) (= castellanii (Hirst)) (Acarina: Acaridae) (Robertson, 1959). Individual rearings, however, were required to obtain detailed information on the life history, behaviour, and ecological requirements, prior to the use of this species as an experimental animal in the study of predatorprey interactions. This paper is an account of the various techniques tested and of the observations made throughout these studies.

The nature of systematics and its fundamental importance to other branches of biology have already been ably discussed by such authors as Simpson (1961) and Mayr (1963, 1969). Thus, in defining systematic entomology, we may paraphrase Simpson (1961): Systematic entomology is the scientific study of the kinds and diversity of insects and associated arthropods and any and all [biological] relationships among them. “Modern” merely implies current and recent, not avant-garde, although this is not excluded.

Leek moth, Acrolepiopsis assectella, recently became established in the Ottawa Valley, where it significantly damages garlic, leek, and onion (Allium L., Liliaceae) crops. At a threshold of 7 °C, populations in eastern Ontario require 444.6 day-degrees to develop from egg to adult. Pheromone-trap data identify spring, early-summer, and late-summer flight periods of overwintered 1st- and 2nd-generation adults, respectively. Depending on ambient temperatures, the life cycle takes 3–6 weeks in the field, with three generations possible. Management strategies such as application of reduced-risk foliar insecticides and use of row covers require precise timing to target appropriate life-cycle stages. Implementation windows can be determined by incorporating pheromone-trap data and ambient air temperature into a life-cycle development model. A proposed integrated pest management program will involve the use of pesticides, mechanical barriers, and classical biological control.

A sequential egg-band sampling system for predicting defoliation of aspen by the forest tent caterpillar (Malacosoma disstria Hbn.) is described and its accuracy assessed. A probability method of predicting defoliation from the stage of the outbreak in each local area is also established. A third method, which promises to be the most accurate and consistent, is proposed. In this last system, egg-mass density is established and related to defoliation levels which are adjusted depending upon age of outbreak.

Honey inhibits esterolytic and proteolytic activity of trypsin from Aedes aegypti, Culex pipiens quinquefasciatus, and cattle. The inhibitor is heat stable and only a portion of the inhibition capacity is lost from the honey by dialysis. Glucose, fructose, and sucrose have no effect upon trypsin but ascorbic acid and riboflavin are inhibitory while gluconic acid is an activator. Nectar from lilies but not from honeysuckles inhibits C. pipiens quinquefasciatus trypsin.

Sex ratios at emergence of Aedes impiger and A. nigripes in the Hazen Camp area (81°49′ N., 71°18′ W.), northern Ellesmere Island, N.W.T., are given from trap records, mainly for 1963.

There is a marked predominance of females in trap catches from temporary ponds, and an overall slight predominance of females (but with marked pond-to-pond variation) in permanent ponds. The nature of these inter-pond differences favours the inference that, before emergence, males normally survive less well than females, especially under the conditions existing in temporary ponds as they dry up.

Colonies of the honey bee, Apis mellifera Linnaeus, infested with the parasitic mites Acarapis woodi (Rennie) (Acari: Tarsonemidae) or Varroa jacobsoni Oudemans (Acari: Varroidae) require acaricidal treatment to control infestations that could affect colony growth and honey production. We investigated the effects of three acaricides, fluvalinate (formulated as Apistan®), formic acid, and menthol, on honey bee colony population growth, foraging activity, adult worker longevity, and honey production. Effects of in-hive treatments of Apistan® and formic acid were measured by examining colony weight gain, brood survival, sealed-brood area, emerged-bee weight, number of returning foragers, pollen-load weight, and worker longevity. These characteristics were not different between fluvalinate-treated colonies, formic-acid-treated colonies, and control colonies. Adult bee population, brood survival, number of returning foragers, and honey production did not vary among menthol-treated colonies, formic-acid-treated colonies, and control colonies. Sealed-brood area was lower in formic-acid-treated colonies than control colonies, but not different from menthol-treated colonies. Although not statistically significant, formic-acid-treated colonies experienced lower honey production than both menthol-treated and control colonies. Numbers of workers attending the queen in the retinue and queen behaviour patterns were not different after colonies were treated with formic acid.

The following 14 aphids are known to feed on species of Solidago in Canada: Cachryphora serotinae (Oestlund), Dactynotus caligatus Richards, Dactynotus canadensis new species, Dactynotus erigeronensis (Thomas), Dactynotus gravicornis (Patch), Dactynotus lanceolatus (Patch), Dactynotus macgillivrayae Olive, Dactynotus nigrotibius Olive, Dactynotus nigotuberculatus Olive, Dactynotus pieloui new species, Dactynotus pseudochrysanthemi Olive, Dactynotus tissoti Boudreaux, Dactynotus solirostratus new species, and Macrosiphum goldamaryae (Knowlton). A key and a list of associated host plants are given.

Entomophagous insects as a group show all degrees of host preferences from the polyphagous species which develop on variable numbers of hosts to the stricdy monophagous forms wllich are limited to development on a single host species. Polyphagy is generally regarded as the more primitive condition while the fact that even amnng species so characterized there frequentIy exist strong preferences in the form of host determined races is taken as an indication of one method by which the more specialized habit was attained. The general problem of the dynamics of host selection in the entomophagous Hymenoptera and Diptera has attracted the attention of numerous investigators (eg. Thompson & Parker 1927, Salt 1935, Ullyett 1936) and many have stressed that for any given parasite the range of hosts attacked and developed on is the end result of various processes. These processes have been conveniently described by Salt (1938) as host finding, selection, and suitability, the first phase being more usually referred to as habitat selection (Flanders 1937, Thorpe 1945). This interpretation has received wide acceptance among biological control and allied workers.

Growth, development, and survival were investigated for the larvae of the red turnip beetle, Entomoscelis americana Brown, fed excised cotyledons or first true leaves of four cultivars of Brassica campestris L. (Torch, Echo, Candle, and R500) or three cultivars of B. napus L. (Midas, Target, and Tower) in the laboratory. The red turnip beetle has four larval instars and its growth curve is S-shaped. The seven cultivars of B. campestris and B. napus tested were suitable host plants for the larvae. On all the cultivars, survival was relatively high, the weights and developmental times were similar, and the percentage of malformed adults was low. In B. campestris and B. napus, the cotyledon stage was marginally better than the first true leaf stage as food for the larvae. Survival usually was higher and in one of the three experiments the adults at emergence were heavier on the cotyledons than on the first true leaves. However, the developmental times were similar, except in one of the three experiments where they were longer on the cotyledons, and the incidence of malformed adults was low on both stages of plant growth.

Since the initial observations on the pitcher plant mosquito, Wyeomyia smithii (Coquillett), from 1901 to 1904 by Smith (1901), only limited additional contributions have been made toward the understanding of the biology of this species. Horsfall (1955) indicates that, aside from one 1913 citation and a brief reference to his own observations, all material summarized by him about this species was reported by Smith. For the past 50 years, mosquito workers have generally limited their observations on W. smithii to statements of seasonal development in nature, this usually being in conjunction with a more detailed regional study emphasizing the ecology of other mosquito species. The wellknown specificity for the development of W. smithii only in the pitcher plant, Sarracenia purpurea, undoubtedly has precluded much in the way of laboratory investigations on this mosquito. However, during the summer of 1957, a large number of larvae of this species was found just north of Itasca State Park, Clearwater Co., Minn., and the opportunity presented itself to investigate the possibility of rearing W. smithii independent of the pitcher plant. It is the purpose of this paper to describe a method for the laboratory colonization of this mosquito completely free of any pitcher plant association and to make additional contributions to the biology of this species

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 pseudotsugae Hopkins, 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.

The seasonal phenology of the walnut husk fly (WHF), Rhagoletis completa Cresson, was studied in the Willamette Valley of Oregon during a 4-year period (1990–1993). Adult emergence observed in ground emergence cages varied greatly among years. Initial emergence ranged from 29 June to 17 July, and last emergence occurred as early as 17 August or as late as 11 September. The period of adult emergence was constant from year to year (mean 55, range 50–60 days) with the peak between the 3rd week of July and the 1st week of August. The period between first observed appearance of females in ground-level emergence cages and the first oviposition was consistent among the study years, ranging from 20 to 23 days. Peak oviposition occurred in the 2nd and 3rd weeks of August. Mean egg hatch and larval survival were 98 and 80%, respectively. Infestations reached over 95% in unsprayed trees by early to mid September. Mature larvae first exited from husks beginning the 4th week of August and continued through mid October. Larvae penetrated the soil and pupated at a depth of 2.5–7.6 cm with most within the top 2.5 cm of soil.

Specimens of five species of woodpeckers (Piciformes: Picidae) from Manitoba, Canada, were weighed and examined for chewing lice, 1998–2015: downy woodpecker (Picoides pubescens (Linnaeus), n=49), hairy woodpecker (Picoides villosus (Linnaeus), n=23), pileated woodpecker (Dryocopus pileatus (Linnaeus), n=10), northern flicker (Colaptes auratus (Linnaeus), n=170), and yellow-bellied sapsucker (Sphyrapicus varius (Linnaeus), n=239). The relationship between body mass of each host species and infestation by seven species of lice was analysed: Menacanthus pici (Denny) from all host species, Brueelia straminea (Denny) from Picoides Lacépède species, Penenirmus jungens (Kellogg) from northern flicker, Penenirmus auritus (Scopoli) from the other four hosts, Picicola porisma Dalgleish from northern flicker, Picicola snodgrassi (Kellogg) from Picoides species, and Picicola marginatulus (Harrison) from pileated woodpeckers. Mean abundance of lice increased with the mean mass of their host. Neither the species richness of lice nor the prevalence of lice were related to host body mass. Host body mass explained 98% of the variation in mean intensity of louse infestation among hosts. The positive association of mean intensity and body size was also detected for three genera of lice. Louse intensity also increased with body size for individual birds, more so for some species of lice and hosts than others. Body size matters, but the adaptations that allow higher mean intensity on larger host species remain to be determined.

Coneworms, Dioryctria Zeller (Lepidoptera: Pyralidae), are destructive pests of conifers across North America, and members of several different species groups present significant pest-management challenges in conifer seed orchards. Dioryctria abietivorella Grote (abietella group) is the most pestiferous Dioryctria species in Canada. Despite this status, control tactics are currently limited to broad-spectrum pesticides that threaten non-target species and may result in pesticide resistance. The development of integrated pest management programs targeting Dioryctria species will benefit from a conceptual framework on which to base future research. To create this structure, we review the systematics, evolutionary ecology, and management of cone-feeding North American Dioryctria species. Current research suggests that many species boundaries are in need of further revision. Major gaps in our understanding of Dioryctria ecology impede the development of integrated pest management tactics. For example, host-generated semiochemicals are important in Dioryctria reproduction, although the uses of these cues in host-finding and host acceptance remain unknown. Future research should identify factors that mediate population distribution at landscape (e.g., migration), local (e.g., feeding stimulants), and temporal (e.g., development thresholds) scales.