The importance of the mountain pine beetle to the pine forests of North America has been pointed out by several writers (Hopkins, 1909; Swaine, 1918; Evenden et al., 1943; Hopping and Mathers, 1945). Its range covers parts of southern British Columbia and Alberta, Idaho, Montana, Wyoming, Oregon, Washington, California, Utah, and Nevada. The size of populations and the damage vary from year to year. A study of the biology of the mountain pine beetle was made by the writer from 1955 to 1960 in several small outbreak areas near Invermere, British Columbia. (50°30′ N. lat., 116°00′ W. long., 2740 feet above sea level). The host tree in these areas was lodgepole pine, Pinus contorta Douglas var. latifolia Engelmann. The results of the study will be presented in three parts. Part I is presented herein and describes the life cycle, brood development, and flight periods. Part II is a discussion of the behaviour of the adult as affected by physical factors operating under the bark. Part III describes the interaction of the insect and its host, with special reference to mortality and brood survival.

The role of adult nutrition in longevity, progeny production, and offspring sex ratio of Trichogramma minutum Riley was examined. On average, honey-fed females lived 26.4 days and produced 260 offspring; unfed females lived 3.5 days and produced 80 offspring. Feeding on fructose or sucrose also significantly increased longevity and fecundity over unfed females (fructose, 23 days and 230 offspring; sucrose, 21 days and 230 offspring) but to a lesser degree than feeding on pure honey. Females fed yeast suspension or water had no significant increases in longevity or fecundity compared to unfed females. Offspring sex ratios of long-lived females were male-biased (50–62% males), those of short-lived females were female-biased (74–82% females). Lifetime reproduction of honey-fed females was highest at 20–25 °C and relative humidities of 20–80%, but short-term offspring production (during the first 2 days after emergence) was highest at 30 °C and 60–80% RH. Females that had access to honey for only a 24-h period did not increase their offspring production over the first 4 days of their lives when compared to unfed females. The potential benefits of feeding adult T. minutum for mass-rearing and field release are discussed.

Females of I. conquisitor were conditioned to associate colour with the presence of hosts. Conditioning was important only during searching and did not affect the distribution of attacks once hosts were found. The ability of this species to associate colour with the presence of hosts could increase its efficiency as a parasite. Females of I. conquisitor showed an innate preference for blue over yellow.

Dendroctonus ponderosae (Hopkins) is widely distributed across western North America, feeding in at least 12 native species of Pinus L. (Pinaceae). We investigated the existence of heritable differences in two life-history parameters (adult size and development time) of D. ponderosae from a northern population (central Idaho, Pinus contorta Douglas ex Loudon) and a southern population (southern Utah, Pinus ponderosa Douglas ex P. and C. Lawson). We attempted to separate heritable from environmental effects by rearing individuals from both populations through two generations (F1 and F2) in a common standardized laboratory environment with a constant temperature. Two treatment effects were tested for in the F2 generation: (1) geographic location (source host) for F0D. ponderosae; and (2) the F2 brood host. We hypothesized that, if differences were observed and the F0 source host and region had a greater effect on F2 brood development time and adult size than did the host in which F2 brood were reared, a heritable factor related to the F0 parents was responsible. Time to emergence was significantly shorter for second-generation offspring of the northern population than for second-generation offspring of the southern population, regardless of the F2 brood host. Although both the F2 brood host and F0 source parents were significant in explaining differences observed in the developmental-time distribution of F2 brood, the F0 source effect was found to be much greater. Also, F2 males and females from southern source parents were significantly larger than F2 brood from northern source parents when reared in both F2 brood hosts. Geographic region and original host of F0 source parents had a significant effect on F2 offspring size, whereas the immediate food for F2 brood was not significant in explaining differences. These results suggest genetically based regional differences in D. ponderosae populations.

In a study on the population dynamics of the predators of insect pests in apple orchards of Quebec, three specimens of the Asian coccinellid Harmonia axyridis were found. This is the first occurrence of this species in Canada

The cephalic structures of the final instar larva of 278 species of 140 genera of Braconidae were examined. On the basis of these and biological data, modifications are proposed in the classification of the higher categories. Zele (Helconinae) and Eubadizon (Blacinae) are placed in the Macrocentrinae (endoparasites of larval Lepidoptera) and Meteoridea is moved from the Helconinae and ranked as an independent subfamily. The Blacinae is completely dismembered: Aliolus, Triaspis, Urosigalphus, Blacus, and Calyptus form a tribe of the Helconinae (endoparasites of larval Coleoptera); Microtypus, Orgilus, and Stantonia form a tribe of the Agathidinae (endoparasites of larval Lepidoptera); and Pygostolus, Centistes, and Syrrhizus a subfamily near Euphorinae with Cosmophorus (endoparasites of adult Coleoptera). Present genera of Microgasterinae are separated into two tribes with the addition of the Cardiochilini as a third tribe. The Dacnusinae is reduced to a tribe of the Alysiinae. The Rogadinae is reduced to one tribe, Rogadini, containing only Rogas and allied genera (endoparasites of larval Lepidoptera). Rhyssalus is transferred to the Hecabolini, and Exothecini, Pambolini, Hormiini, and ectoparasitic Rogadini to the Braconinae (ectoparasites of larval Coleoptera, Lepidoptera, etc.). The problematic genus Gnaptodon is also placed in the Braconinae.

The tactic and kinetic responses of adult Dendroctonus ponderosae Hopkins were studied under varying conditions of light, temperature, humidity, gravity, and with different visual forms. Newly emerged adult Dendroctonus ponderosae Hopk. were attracted by high light intensity and utilized spot sources of light and surrounding objects, but not polarized light, for orientation. Flying adults were positively phototactic unless warmed above 35 °C; egg-laying adults were negatively phototactic. High temperatures and light intensities increased the frequency of flights. The beetles were negatively geotropic but this could be masked by the attraction to light. Dark objects on a light background were attractive; the size of the object was important while the shape was not.

Temperature influenced orientation to some extent but its influence on rate of activity was far more pronounced; rate of walk followed a linear relationship with temperature. Humidity also affected orientation and rate of walk to some extent, although its effect was usually masked by other environmental factors.

Severely deformed chironomid larvae have been collected in Lake Erie and two lakes in the Okanagan valley of British Columbia. Deformed larvae had very aberrant mouthparts and the head capsules were usually heavily pigmented. In most cases both the head capsule and body wall were many times thicker than in normal specimens. These deformities are apparently caused by pollutants and it is speculated that agricultural and/or industrial chemicals may be responsible.

Glacier brooks in Northern Scandinavia have been investigated for the occurrence of chironomid larvae and pupae. In the uppermost zone of glacier brooks with a very narrow temperature amplitude, Diamesa lindrothi is the most abundant species. In a lower zone with a wide diurnal temperature amplitude during summer months, the simuliid Prosimulium macropyga is more abundant, along with other species of Diamesa. Lacking any primary organic production, the diptera larvae living here feed on particles drifted up on the glacier surface, conserved there and released into the glacier brook by the melting of the ice. The larvae of Diamesa lindrothi have developed adjustments to obviate the strong water current and the instability of the benthic substratum: The mature larvae spin nets over small stone cavities where they live, and thus prevent the pupal stage from being washed downstream. The Diamesa associations in glacier brooks have to be regarded as distinct freshwater biocoenoses. They have to be considered as belonging to the biocoenosis type kryon, and the brooks themselves according to the biotope type kryal. They differ from the krenal and rhithral biotope types by both abiotic and biotic peculiarities, and from the equivalent biocoenosis types by their characteristic life forms and animal associations.

The dispersal flight of the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, is oriented toward fresh windthrown and cut trees when these are present in the stand, the beetle being attracted by oleoresin, particularly its alpha-pinene, camphene, and limonene fractions. In the absence of such material the pioneer beetle dispersal appears to be rather uniform throughout the stand. This host attraction precedes the beetle attraction which is produced by unmated females shortly after entering the host and which results in mass concentration of beetles around the center of attraction. Of these two phases in the attraction process, the secondary attraction is far stronger than that caused by the fractions of the host oleoresin.

Attraction centers are established only in freshly downed trees and in standing trees of subnormal physiological condition under both latent and epizootic conditions; however, under epizootic conditions, the beetles can invade even vigorous trees in the perimeter of attraction. The survival of such trees depends on their ability to exude oleoresin, which in turn is influenced greatly by environmental factors. The susceptibility of trees to successful beetle invasion is characterized by their oleoresin exudation pressure, which reflects water disturbances in the tree. Diurnal and seasonal fluctuations of the resin pressure are discussed in relation to beetle flight and invasion, and the resin effects upon the beetle (both mechanical and chemical) are considered. The beetles are found to be repelled by Douglas-fir resin and its fractions, i.e. alpha- and beta-pinene, camphene, limonene, terpineol and geraniol, when tested at close range in the laboratory.

Newly emerged adults of Dendroctonus pseudotsugae Hopkins were separated into pairs of similar size. One beetle from each pair was used as a control; the other was flown on a rotating mill. Soxhlet extractions in petroleum ether revealed that the flown beetles contained significantly less fat.

The flight of bark beetles covers a short but important period of their life cycle, during which they are exposed to conditions not encountered during the major portion of their life under the bark. The time of flight and the factors which affect it are important, not only to the dispersal and survival of the insect, but also in the interpretation of experimental data dependent upon the beetle's flight activity.

Chapman (1954), Rudinsky and Vité (1956), and Atkins (1959, 1960, 1961) studied the flight of the Douglas-fir beetle under laboratory conditions, but there is scant reference to field studies on the flight of this insect. Chapman and Kinghorn (1958) recorded the number caught in window flight traps near Cowichan Lake, B.C., and unpublished reports describe emergence records obtained from cage studies conducted near Lumby, B.C.

A non-diapause strain of the migratory grasshopper, Melanoplus sanguinipes (Fabr.), has been developed over the past 12 years by selecting for rearing those grasshoppers that hatched from eggs not previously cooled. Because this strain can be reproduced at the rate of six to seven generations per year it is proving to be a useful experimental animal.

The life history of the European earwig at Vancouver, B.C., is described and divided into two periods: the nesting phase and the free-foraging phase. Seasonal changes in population characteristics are documented and compared in sparsely and densely vegetated habitats. The developmental rates, population sizes, and sex ratios, but not the body weights, differ between the two habitats. Suggested reasons for these differences are advanced.

The sex pheromone of the female eastern spruce budworm was identified as trans-11-tetradecenal by a combination of electroantennogram techniques, laboratory bioassays, and chemical analysis. Subsequent field trapping showed that this compound is a potent attractant for both male Choristoneura fumiferana (Clem.) and C. occidentalis Free, thus supporting its identification as a sex pheromone of the eastern spruce budworm and suggesting that it is also a major component in the pheromone system of C. occidentalis.

Captive colonies of Bombus terricola Kirby received pollen for 8, 14, or 24 h per day from the time of onset of second brood oviposition until colony decline. The pattern of change of worker body size over time, especially between the first and second broods, varied according to these experimental food regimes. The results indicate that conflicting results reported in the literature, with respect to changes in worker size over the course of colony development, probably can be regarded, at least in part, as the outcome of differences in food supply.

Various aspects of the behavior of I. confusus (LeConte) relating to the production of and response to male attractant were studied. Storage at 8.0 °C and 100% R.H. had no adverse effect on survival, response to male attractant, or predisposition to fly. Low humidity and high temperatures (21 °C) adversely affected behavior and survival. Beetles conditioned either in natural or constant environments responded at high levels throughout a 24-hour period. Female response to male frass reached a low of 24.2% in January and February and rose to a peak of 76.6% in May and June. Response to benzene extract of male frass fell moderately during autumn and winter, indicating a lowered response ability for overwintering populations. Male response was lower and more erratic but followed the same seasonal trends.

After brief exposure periods, even previous nonresponders oriented to male attractant at significantly higher levels than the total original population. Long-term confinement in an atmosphere containing male frass odor caused a reduction in response of both sexes to male frass extract, presumably because of adaptation of olfactory receptors.

Flight attempts by both sexes occurred between 25° and 40 °C but were severely inhibited at these extremes. Light intensities below 431 luxes suppressed flight. Optimal take-off temperatures were 30 °C for males and 32.5 °C for females. Both contact with male frass and with attractive air reduced the take-off attempts of both sexes to near zero. Attractive odor in the air still suppressed flight significantly after beetles had been conditioned up to 4 hours in contact with male frass.

Teneral males produced attractant after a long maturation period. Single, mature males produced attractant up to 18 days, but after mating, productivity declined in direct correlation with the number of females per male. Single males produced frass throughout the day but maximum production was coincident with peak female emergence and flight. Male frass was significantly less attractive 15 minutes after exposure to open air and after 1 hour, very little attraction remained.

No trends in the ability of newly emerged adults to respond to male attractant were noted over a 30-day period. Emerging brood and re-emerging parent adults are responsive to flight stimuli, but darkened callows and parent adults removed from galleries could not be induced to fly. Reproducing females show a greatly reduced response to male attractant.

The present work demonstrates how important food quality is to an insect. When the dietary inadequacy in an artificial food was dilution of its nutrient content to 85, 70 and 50%, respectively, fifth-instar Celerio euphorbiae (Linnaeus) ate progressively more food but they gained no more body weight on one diet than on another. The rate of food intake depended on nutrient concentration. On all nutrient levels the larvae were about 20% efficient in converting the foodstuff into body material and the body content of protein did not differ significantly.

When the dietary inadequacy was immoderate proportions of several nutrients, the effects were not so clearly marked; nevertheless, the rate of food intake of the larvae could explain their body weight. The tendency seemed to be for the larvae to eat less and to gain less weight on the imbalanced diet than on an adequate diet. Moreover, conversion of foodstuff into body material did not seem as efficient on the imbalanced diet as on the control.

The ecological significance of food quality suggested by the first example is that the destructiveness of phytophagous insects, for example, may depend in part on the degree of succulence and corresponding nutrient concentration of food plant tissues; and by the second example, that perhaps nutritional imbalances may play a part in controlling the potential destructiveness of insect populations.

Agrilus bilineatus (Weber) is univoltine in Wisconsin. Adults were present from early June through mid-September; however, peak flight and oviposition occurred during the second half of June. Adults consumed significantly more oak foliage than foliage of hardwoods other than oak. Stressed oaks attracted significantly more adults than did uninjured controls, as measured by density of captured adults on sticky traps. Four larval instars were determined; instar IV was the overwintering stage. Fourth instar larvae generally overwintered in pupal cells in the outer bark or in sapwood if the bark was thin. Larvae, especially third and fourth instars, damaged oaks by girdling the conducting xylem and phloem. Attacked oaks had low root starch content relative to those unattacked. Tree death normally resulted after 2 or 3 years of borer infestation, yet tree death may occur in a single season. Initial attack usually began in the live crown and proceeded downward in succeeding years with no apparent reinfestation of previously killed areas. Mean adult longevity in days for adults fed red oak foliage was 28.1 at 20°, 37.8 at 24°, and 8.3 at 30 °C. Mean duration of the pupal stage in days was 11.7 at 24 °and 8.5 at 30 °C.

It is necessary to demonstrate the host specificity of an exotic phytophagous insect before introducing it for the biological control of a weed. The widely-used "starvation test" made on economic plants is considered inadequate for this purpose and we propose that studies should be broadened to include the following: (1) study of the insect’s biology, including host–plant records, with particular attention to adaptations likely to restrict the host range, (2) review of the plants attacked by related insects, (3) determination of the laboratory host range of the insect, (4) investigation of the chemical or physical basis of host–plant recognition, (5) starvation tests on economic plants to confirm the limits of the previously established host range, (6) establishment of the insects’ potential effectiveness for weed control. A limited amount of feeding on economic plants in the laboratory is not reason for rejection, if other criteria show the insect has a high degree of specificity.