An outbreak of the European spruce sawfly, Diprion hercyniae (Htg.), occurring in Eastern Canada between 1930 and 1942, was controlled by a virus disease (Balch and Bird, 1944). The sawfly has been kept at a low level by the disease and by parasitic insects introduced from Europe (Bird and Elgee, 1957).

An infestation of the sawfly was discovered in 1947 near Sault Ste. Marie, Ontario, by the Forest Insect Survey Section of the Forest Biology Laboratory at Sault Ste. Marie. This infestation was about 100 miles beyond the previously known western distribution of the insect. Intensive larval sampling in 1949 showed that it was free from virus and practically free from introduced parasites. Thus, an excellent opportunity was provided to introduce the virus into a disease-free population, to study its establishment and spread, and to compare the long term effects of virus alone on population trends with the effects that virus plus introduced parasites were shown to have on population trends in New Brunswick (Bird and Elgee, 1957). The virus was introduced into the infestation in 1950 and studies were carried out each year from 1950 to 1959.

Reproductive and survival patterns of the heteropteran predator Podisus maculiventris (Say) (Heteroptera: Pentatomidae) were measured under low prey inputs. A single prey, mealworm larva (Tenebrio molitor L.), of one of two sizes (120 or 30 mg), was given to predators for a 24-h period every 1, 2, 4, 8, or 16 days. Additional treatments included: predators provided prey in excess of attack rates; predators given no food; and predators given green bean slices only. Results showed that predators provided with prey survived regardless of feeding interval. When given large prey, predators showed reproductive patterns that were not clearly reflective of feeding interval; only predators fed at 8- and 16-day intervals showed reduced fecundity. When given small prey, the reproductive patterns of predators clearly reflected the feeding intervals. Predators that were fed less frequently laid fewer eggs, less often, and later in life.

Studies of the mountain pine beetle by DeLeon (1934), Evenden et al. (1943), Hopping and Mathers (1945), have shown that females frequently establish more than one egg gallery each season, Recent studies by the author indicate that females commonly leave their first egg galleries after a period of 2-3 weeks and fly to another tree where the second egg galleries are established.

The biology of the mountain pine beetle was studied in 1956 and 1957 near Invermere, in the East Kootenay region of British Columbia. The host tree was lodgepole pine (Pinus contorta var. latifolia Engelm.). The technique used permitted direct observation of mating, egg laying, and gallery construction. The sex ratio was also investigated under natural conditions and in cages. The most important previous work on the biology of this insect was done by De Leon, Bedard, and Terrell (1934).

Queenless, caged, newly emerged worker bees (Apis mellifera L.) were fed honey, 22 and 40% pollen in honey, and 22 and 40% royal jelly in honey for 14 days. Workers fed royal jelly, pollen, and honey had large, medium, and small ovaries, respectively. Royal jelly had higher nutritive value for workers’ ovarian development than did pollen, possibly because royal jelly is predigested by nurse bees and easily used by adult and larval bees. These results suggest that nurse bees could mediate workers’ ovarian development in colonies via trophallactic exchange of royal jelly. Six levels of royal jelly in honey, 0, 20, 40, 60, 80, and 100% (royal jelly without honey), were tested for their effects on workers’ ovarian development and mortality for 10 days. High levels of royal jelly increased ovarian development, but also increased worker mortality. All caged bees treated with 100% royal jelly died within 3 days. When workers were incubated at 20, 27, and 34 °C for 10 days, only bees at 34 °C developed ovaries. These findings suggest that nurse bees functioning as units which digest pollen and produce royal jelly may feed some potentially egg-laying workers in a brood chamber with royal jelly when a queen is lost in a colony. Feeding workers a diet of 50% royal jelly in honey and incubating at 34 °C for 10 days is recommended for tests of ovarian development.

The alarm pheromone of the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is present in the droplet of anal fluid produced by second-instar nymphs when attacked by predators. Because the anal droplet is used in defense against arthropod predators, it was hypothesized that the alarm pheromone (decyl acetate plus dodecyl acetate) acts as a defensive allomone. This hypothesis was refuted by the demonstration that two predators use the pheromone as a prey-finding kairomone. On a leaf arena, Orius tristicolor White (Hemiptera: Anthocoridae) increased its rate of turning in response to the pheromone, and spent 25% of its time within 5 mm of a pheromone source. When given a choice between connected leaf discs containing a pheromone- or solvent-treated wick, Amblyseius cucumeris (Oudemans) (Acarina: Phytoseiidae) spent a greater proportion of time on the pheromone-containing disc, suggesting an arrestment effect.

I examined the relative feeding preferences of five carabid beetle species for terrestrial gastropod prey. Scaphinotus marginatus Fischer, thought to be a snail specialist, discriminated among seven species of potential prey by size and species, with the slug Deroceras reticulatum (Müller) being the most preferred. Scaphinotus marginatus appears to use its elongated and narrowed mouthparts, head, and thorax to prey upon terrestrial snails without having to crush their shells. The relative feeding preferences of four pterostichine generalist predators (Pterostichus adstrictus Eschscholtz, P. pensylvanicus LeConte, P. protractus LeConte, and P. surgens LeConte) for two species of small snails [Discus cronkhitei (Newcomb) and Euconulus fulvus (Müller)] also were examined. Although all four carabids ate E. fulvus in varying proportions, only P. protractus consumed D. cronkhitei. I suggest that snail shell thickness and differing feeding preferences affect which snail species are eaten by these pterostichines.

Larvae of the wheat midge, Sitodiplosis mosellana (Géhin), feed on developing seeds of common and durum wheats, Triticum aestivum L. and Triticum durum L. (Graminae). The trophic relationships between insect and plant were quantified as biomass gains or losses using plants infested artificially in the laboratory and naturally in plots and commercial fields. The biomass of seeds from different parts of a wheat spike varied, but seeds in all parts of a spike were infested, independently of their potential biomass. Most infested seeds had 1–3 larvae, but at least 11 larvae could mature on a single seed without reducing larval biomass. When larvae finished feeding and seeds attained about one third of their biomass, specific impact varied from 4.1 to 8.5 mg of seed biomass lost for each milligram of biomass gained by a larva, with the impact declining as the number of larvae per seed increased. Specific impact rose to 100 mg/mg as seeds of T. aestivum and a primitive wheat, Triticum monococcum L., matured, and higher still for T. durum. Wheat plants did not compensate for wheat midge damage, and no indirect damage to uninfested seeds was detected. The distribution of biomass for infested seeds was bimodal, with over 40% less than 8 mg when hand harvested, whereas infested seeds harvested mechanically had a unimodal distribution, with nearly all of the most severely damaged seeds removed during harvest. A visual rating system of six damage categories was related to the biomass of the seeds. The germination and early growth rate of infested seeds were reduced compared with those of uninfested seeds. Based on the biomass relationships for the insect–plant interaction and the visual rating of damage, high-protein number 1 grade common and durum wheat and number 1 grade durum wheat can tolerate up to 6% of the seeds being infested by larvae, before downgrading is likely. For other grades, the economic threshold is 10% of the seeds infested, based on yield loss. Seed growers can adopt the threshold for number 1 wheat (6% infestation) to prevent downgrading, which would also reduce the effects of infestation on seed germination to an acceptable level.

The fauna of introduced rove beetles (Staphylinidae) in the Maritime Provinces of Canada is surveyed. Seventy-nine species have now been recorded. Of these, 73 have been found in Nova Scotia, 29 on Prince Edward Island, and 54 in New Brunswick. Twenty-five species are newly recorded in Nova Scotia, 16 on Prince Edward Island, and 10 in New Brunswick, for a total of 51 new provincial records. Of these, 15 species, Tachinus corticinus Gravenhorst, Mycetoporus lepidus (Gravenhorst), Habrocerus capillaricornis (Gravenhorst), Aleochara (Xenochara) lanuginosa Gravenhorst, Gnypeta caerulea (C.R. Sahlberg), Atheta (Microdota) amicula (Stephens), Cordalia obscura (Gravenhorst), Drusilla canaliculata (Fabricius), Deleaster dichrous (Gravenhorst), Coprophilus striatulus (Fabricius), Carpelimus subtilis (Erichson), Leptacinus intermedius Donisthorpe, Tasgius (Rayacheila) melanarius (Heer), Neobisnius villosulus (Stephens), and Philonthus discoideus (Gravenhorst), are newly recorded in the Maritime Provinces. Two of these, Atheta (Microdota) amicula and Carpelimus subtilis, are newly recorded in Canada. Leptacinus intermedius is removed from the faunal list of New Brunswick and Philhygra botanicarum Muona, a Holarctic species previously regarded as introduced in North America, is recorded for the first time in the Maritime Provinces. An examination of when species were first detected in the region reveals that, on average, it was substantially later than comparable dates for other, better known families of Coleoptera — an apparent indication of the comparative lack of attention this family has received. Some introduced species appear to be associated with the dry-ballast mechanism of introduction to the continent, while others are synanthropic and may have been inadvertently introduced in connection with agriculture, horticulture, or other processes associated with human activities. A substantial number are now established and well distributed, seemingly indicative of an early introduction into the region, the ability to successfully colonize a habitat and disperse within it, or a combination of these factors. Other species appear to be local in distribution, perhaps indicative of more recent introductions, more restricted ecological tolerances, a lesser ability to disperse, or a combination of these factors. These recent discoveries are discussed briefly in the context of the importance of taxonomic research and ongoing monitoring in order to detect and identify exotic species and monitor for new introductions and changes in existing native or introduced populations — all important in terms of assessing the risk of introductions to, and their impact on, native faunas and habitats.

Severe defoliation of aspen stands by the forest tent caterpillar, Malacosoma disstria Hbn., became apparent in 1948 in three widely separated regions in Ontario, and by 1949 it was clear that another general outbreak of this defoliator had begun. In 1950 the Forest Insect Survey (cf. McGugan, 1958) initiated an intensive program of observation, collecting, and rearing to record the progress of the outbreak and study the parasite complex of the insect. This paper compares the outbreak in the early ‘fifties’ with earlier ones, and attempts to describe the pattern of build-up and decline of forest tent caterpillar populations within extensive forested areas.

The flight habits of any scolytid beetle are an important aspect of its biology, and times of flight should be known for effective chemical protection of logs against its attacks. Consequently, during the course of biological and chemical control investigations of the ambrosia beetle, Trypodendron lineatum (Oliv.), from 1954 through 1956, much attention was directed to a study of its flight activity. This species is well known to attack early in the spring. There are other attack flights later in the season but far fewer beetles are involved then. The beetles also fly at the time they leave the brood logs to enter forest litter, where they overwinter. Several methods were used to study the influence of weather, season, and other factors on flights of Trypodendron and, to a lesser extent, of other scolytids. These methods and some of the data secured are described and discussed in this paper.

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 convergens Guérin-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 that H. convergens can 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.

The boreal zone of Canada extends across the continent over millions of square kilometres. Characterizing the insects of this cool temperate zone is especially important for an understanding of the Canadian fauna in general, and for northern forestry. The boreal zone supports simple coniferous forests with some deciduous trees and an understory of a few common vascular plants, mosses, and lichens. This enormous area of apparently similar vegetation nevertheless shows very great spatial and temporal heterogeneity, with a wide range of subhabitats. Aquatic habitats of many different kinds are especially well represented in the zone. The diversity of terrestrial habitats is maintained chiefly by disturbance, especially fire and seasonal flooding, and contributes greatly to faunal diversity.

About 22 000 insect species are estimated to occur in the zone, far fewer than in more southern zones. Northern taxa, notably Diptera, are relatively well represented. The distributions and patterns of variation of the species are summarized. About half have transcontinental ranges, and many occur also in forested habitats in the western mountains south of the boreal zone. About 8% of the species appear to be holarctic. Few species that occur in the boreal zone are strictly confined to it, however. Generalist species in fresh water and other widespread habitats are conspicuous. Many species are centred farther south, and extend northward into the zone to varying degrees.

Adaptations to northern conditions have been reported in many boreal insects. For example, the short growing season is reflected by the prevalence of univoltine species. Insects survive the long cold winters by cold-hardiness and dormancies. Species from disturbed habitats disperse widely. The limited diversity of resources is confirmed by the fact that the food range of some groups of herbivores is wider than in their southern relatives.

Boreal ecosystem relationships are complex, especially relative to the arctic. Numerous associations among insects, and between insects and other organisms, have been demonstrated. However, some evidence suggests that the structure of northern biotic communities might depend more on the tolerances of individual species than on interactions among the species.

The population dynamics of boreal forest insects, notably the spruce budworm, are discussed. In view of the spatial and temporal complexity of the boreal zone, the diversity of interactions with abiotic and biotic factors, and the prevalence of data that correlate with rather than explain population changes, our current failure to understand “outbreaks” of certain boreal insects is not surprising, because many factors probably combine to determine the population of a given species at a given lime and place.

Information on most aspects of the composition and biology of the boreal fauna is incomplete. Data on boreal species have been collected chiefly in southern transitional ecosystems adjacent to boreal zones, rather than in truly boreal systems. Basic taxonomic information on several important taxa, as well as detailed taxonomic and morphometric information about individual species, is especially scanty. However, substantial and coordinated studies of boreal faunas will yield information of great interest and value. Some approaches relevant to further work in taxonomic and ecological arenas are suggested.

Phytophagous orchard mites have become so troublesome in British Columhia during the last decade that special attention has been given to studies on their ecology and control. An important prerequisite for such studies is an accurate and rapid method of estimating population densities of both the mites and their predators. As some mites are less than a fifth of a millimetre long, it is difficult to determine the numbers of adults present on foliage, quite apart from the eggs and other immature stages.

Methods for estimating orchard mite populations developed to date may be classified as either direct, in which the mites are counted on the leaves or estimated, or indirect, in which the mites are removed from the leaves and a known fraction is counted.

The flight of the ambrosia beetles, Trypodendron lineatum (Oliv.), Gnathotrichus sulcatus Lec. and G. retusus Lec., revealed distinct diurnal and seasonal patterns that were influenced by environmental factors, particularly temperature, wind, and daylight. While Trypodendron flies during the entire day when the temperature is favorable, the Gnathotrichus species exhibit a peak of flight at dusk. The temperature thresholds of emergence and initiation of flight for Trypodendron and the threshold for flight of Gnathotrichus were established.

The substance responsible for mass attraction of Trypodendron, after the initial invasion of a few pioneer beetles, was found to be a species-specific sex pheromone produced by sexually mature females after entering the host. The pheromone has been concentrated from the female borings in the laboratory, and when released in the field it caused the beetles to respond. Both species of Gnathotrichus, on the other hand, responded to the borings produced by female beetles of Dendroctonus pseudotsugae Hopkins and to the extract prepared in alcohol. This fact suggests possible use of these substances in control of these ambrosia beetles.

Honeydew utilization by the ant Lasius niger L. (Hymenoptera: Formicidae), honeydew excretion cost for the aphid Aphis craccivora Koch, and ant protection service for aphids against the lady beetle Coccinella septempunctata L. (Coleoptera: Coccinellidae) were examined in a laboratory. The duration of honeydew utilization by ants increased with increase in aphid density. The presence of ants shortened the residence time of the lady beetle larva on a plant and reduced the proportion of aphids eaten. At a density of 5 aphids per plant, one aphid with ants excreted honeydew at a frequency two times higher than that of an aphid without ants, but not at a density of 100 aphids per plant. Therefore, a larger aphid colony may increase the benefit and decrease the cost of ant attendance.

The results of systematically-conducted, mid- to late-season observations and experiments on large populations of apple maggot flies, Rhagoletis pomonella (Walsh), in apple and sour cherry trees revealed the following sequences in courtship behavior. When environmental conditions are favorable, sexually mature males and females fly to the host fruit, the site of assembly for mating and the site of oviposition. Either sex may initiate the flight which takes it to the particular fruit occupied by a member of the opposite sex. Such flights by males are often in response to the visual stimulus of a female (or male) moving about on a fruit, while such flights by females seem to be primarily in response to the fruit as a potential oviposition site. Once on the same fruit, a male and a female locate one another apparently solely through vision, particularly movement. They walk to within 1–3 cm of one another, but there is no tactile contact until such time as the male attempts copulation by jumping onto the back of the female from this distance.

The position from which the copulatory jump is made is variable. Sometimes it is made from a face to face position, with one or both flies having waved its pictured wings at the other. Occasionally it is made from the side or from a flight from a nearby fruit directly onto a female’s abdomen. Most often however, it is made when a male is stimulated by the forward movement of a female, approaches her from the rear, and jumps onto her abdomen from the rear without the female having seen the male. Most copulation attempts, and especially most successful attempts, are initiated while the female is engaged in some phase of oviposition behavior. Males attempt copulation with other males just as often as with females, strongly suggesting that at least up until the time of tactile contact, males are unable to distinguish between the sexes. The fact that a number of male and female apple maggot flies was observed in copula with R. fausta flies in sour cherry trees suggests that neither sex may be able to discriminate too well between members of its own species and members of other species whose wing and body patterns are similar in appearance However males were usually, although not always, able to distinguish stable flies from apple maggot flies prior to tactile contact.

We discuss the known and possible roles of various visual, chemical acoustical, and physical-tactile cues involved in the courtship behavior and suggest that the most important factor insuring reproductive isolation in apple maggot flies at the pre-copulatory stage may be the selection of the proper host plant for oviposition and hence for assembly for mating.

Larvae of the family Chrysopidae possess characteristics useful in classification at the species, genus, and subfamily levels. This study, which initiates a comprehensive analysis of chrysopid larval systematics, describes the important external characteristics of the family and discusses those features which vary between taxa within the family.

The carnea- group of the Chrysopa, subgenus Chrysoperla, includes six described North American species, most of which are important in pest management. This paper defines the series of characters unique to the larvae of this taxon, presents a key to all larval instars of the six species, and describes the three larval instars of each species, most of which were previously undescribed.

The eggs of seven species of locally occurring coccinellids were reared at constant temperatures. The survival of eggs to hatching, rate, and thermal requirements for hatching were determined. The results were used to evaluate the importance of thermal adaptation of coccinellids in selecting them as biological control agents and in determining the relative species composition of locally occurring faunas of coccinellids.

Very little work has been done on the life history or habits of Mallophaga. Only two papers have heen published since 1913 which give even a general discussion of the life history of these parasites. The number of instars through which the insects pass was not determined in either case. For the experiments reported in this paper, the pigeon louse (Columbicola columbae [Linnaeus]) was chosen because of the ease of obtaining and handling the common host, Columba livia Linn.