A mark–release–recapture study was conducted with dye-marked eastern subterranean termites, Reticulitermes flavipes (Kollar), at two sites in metropolitan Toronto. Interconnected termite galleries were found to extend up to 79 m and to cover areas of 266 and 1091 m2. Colony foraging populations at the two sites were estimated at 2.1 and 3.2 million termites. These foraging distances and population estimates exceed those reported for R. flavipes in other regions.

The southern pine beetle, Dendroctonus frontalis Zimmermann, was studied in the laboratory to determine the influence of associated fungi on its reproduction. First-generation (P) surface-sterilized beetles associated with mycangial fungi (Ceratocystis minor [Hedgecock] Hunt var. barrasii Taylor or SJB 122) constructed more galleries and laid more eggs, at faster rates, than P beetles not associated with these mycangial fungi. No significant differences occurred among non-surface-sterilized P beetles associated with the phoretic blue staining fungus Ceratocystis minor (Hedgecock) Hunt and mycangial fungi or among progeny of P beetles (F1 generation) carrying mycangial fungi. P and F1 surface-sterilized beetles produced more eggs at a greater density than non-surface-sterilized beetles associated with blue stain, but gallery length and the rate of construction were not different. P and F1 surface-sterilized beetles laid more eggs and constructed galleries faster than surface-sterilized beetles that carried no mycangial fungi. The re-emergence rate of beetles was fastest for P beetles associated with C. minor and significantly slower for fungus-free P beetles, P beetles carrying only mycangial fungi, and F1 beetles, respectively. The F1 generation emerged fastest when associated with both mycangial fungi and slowest when associated with SJB 122, and C. minor var. barrasii or no fungus, respectively. This study employed a successful new rearing technique for isolating specific southern pine beetle/fungal associations.

During the 1977–1986 outbreak of mountain pine beetle (Dendroctonus ponderosae) in southwestern Alberta and Saskatchewan, populations of this beetle developed in lodgepole pine and limber pine stands, and threatened to spread northeasterly to the extensive jack pine forests in the central parts of the two provinces. To assess jack pine as a potential new breeding host, I compare egg galleries, brood production, and adult characteristics of D. ponderosae reared in lodgepole, limber, and jack pine logs. Brood productivity, beetle size, sex ratios, and egg gallery characteristics are described for beetle populations reared from naturally infested limber pine logs from southwestern Alberta, and from artificially infested jack pine logs from east-central Alberta and central Saskatchewan. In a field experiment where logs of the three hosts were placed together, adult beetles and their gallery characteristics are described and compared on the three hosts. The results confirm that jack pine is a viable host, that D. ponderosae’s attack characteristics, survival, and progeny on jack pine all appear comparable to those characters observed for beetles reared on lodgepole pine, and that limber pine is highly productive of beetle brood.

The relationship of western spruce budworm outbreaks and population collapse to weather parameters was examined using long term weather records from two stations in the budworm outbreak area of British Columbia and outbreak patterns obtained from Forest Insect and Disease Survey records and from tree stem analyses.

Outbreaks were associated with warm dry summers in conjunction with synchrony of larval emergence and bud flush. Collapse of the last two outbreaks was clearly associated with extreme high temperatures following moth flight. Collapse of the earlier outbreaks may have been due to asynchrony between larval emergence and bud flush.

Well-fed, mated female spruce budworm (Choristoneura fumiferana (Clem.)) show little activity during the first 24 h after emergence. During the second 24 h they lay between 33 and 50% of their egg complement. During the third 24 h most flight activity occurs. Smaller, artificially starved females are much more active, especially during the second 24-h period, when many fly before ovipositing. Timing of oviposition and flight is under photoperiodic control: female flight occurs just before dark after peak oviposition while male activity starts before dark, but peaks after dark, with a morning peak of variable intensity.

Females of Nemeritis canescens (Grav.) were conditioned to associate the odour of geraniol with the presence of hosts. Females conditioned for 10 days retained the conditioned response for 6 days. Associative learning in N. canescens, an oligophagous parasite, is less strong than in Itoplectis conquisitor (Say), a polyphagous parasite. This finding may reveal a general difference between oligophagous and polyphagous parasites.

The efficiency of an entomophagous parasite may be defined as the capacity which it possesses for distributing its eggs among the available host population in such a manner that its progeny have the best possible chance of survival. This capacity is determined by a number of factors which are, as yet, imperfectly understood. Among these factors are the ability of the parasite female to discriminate between hosts which are suitable for the development of her progeny and those which are not; the relative densities of the parasite and host populations; the habits of the host insect; and the behaviour of the parasite itself during oviposition.

In Hylemya brassicae (Bouché) little oviposition occurred when access to host plant material was denied. The mustard oil, allyl isothiocyanate (AITC), stimulated the flies into greater activity and attracted them to its source. Sinigrin and four other glucosinolates (mustard oil glucosides) tested induced oviposition. AITC by itself did not induce, oviposition, but in the presence of a glucosinolate, small concentrations of AITC caused an increase in the number of eggs laid. Glucose, sucrose, casein, wheat germ oil, and a mixture of B-vitamins did not influence oviposition at the concentrations tested, but casein hydrolysate inhibited it. The role of glucosinolates and common nutrients in host selection by H. brassicae is discussed.

An artificial diet for rearing the codling moth is described. It is a modification of a casein–wheat germ diet that was initially developed for the cabbage looper. Agar was replaced by a mixture of wood sawdust, wheat flour, and wood pulp. Growth of microorganisms was controlled by sorbic acid and aureomycin, and by lowering the pH of the diet to 3.5 with citric acid. Production cost for dietary ingredients was about $1/1000 moths. The moths were slightly smaller than those reared on apple. When confined in cages, the sterilized diet-reared moths were somewhat less competitive than the apple-reared insects. However, sterilized diet-reared male moths released in an apple orchard dispersed more rapidly than sterilized apple-reared males.

When spruce budworm larvae emerge in the spring, they either mine the needles of old foliage or feed upon the freshly opened staminate flowers of balsam fir. As soon as the vegetative buds begin to expand, the larvae abandon the needle mines for this newer and more succulent growth. Later, when the pollen is shed, the staminate flowers are in turn abandoned in favour of new shoots. Usually, the larvae continue to feed on the new shoots until pupation. When this insect reaches epidemic proportions, however, the current year's growth is often totally destroyed prior to the completion of the larval stage. Late spring frosts have also been known to destroy, in part, or even completely, the shoots of the current year's growth. Under these conditions spruce budworm larvae must resort to feeding on old foliage.

Laricobius nigrinus Fender, native to the Pacific Northwest, is being evaluated as a potential biological control agent of the hemlock woolly adelgid, Adelges tsugae Annand, in the eastern United States. Members of the genus Laricobius feed exclusively on adelgids. Adelges tsugae is found on hemlocks (Tsuga sp.) in North America and Asia, but is considered only a pest of eastern [Tsuga canadensis (L.) Carrière] and Carolina (Tsuga caroliniana Engelmann) hemlocks in eastern North America. This is the first detailed study of the life history of L. nigrinus and its interaction with A. tsugae. Results of a 2-year field study conducted in a seed orchard in British Columbia on the seasonal abundance of L. nigrinus and its prey, A. tsugae, revealed that (i) the sistens generation of A. tsugae matures 2-3 months earlier than previously reported in Virginia and Connecticut, (ii) no A. tsugae sexuparae were observed, which differs from findings in Virginia and Connecticut, (iii) L. nigrinus adults undergo an aestival diapause that coincides with diapausing first instar A. tsugae sistens, and (iv) oviposition and subsequent larval development of L. nigrinus coincides with oviposition by the A. tsugae sistens adults, indicating good synchrony between L. nigrinus and suitable prey stages of A. tsugae.

The wheat midge Sitodiplosis mosellana (Géhin) occurred in all wheat-growing areas of Manitoba during 1993–1997, with 95% of spring wheat fields having some seeds infested by larvae. The level of infestation varied, but each year in excess of 20% of seeds were infested in some fields. Infestation levels in adjacent fields were more similar than in fields separated by a few kilometres. Within fields, the infestation was similar at the edge and near the centre. Wheat midge larvae also overwintered in, and adults emerged from, fields in all wheat-growing areas of Manitoba. Adults emerged from the end of June to the end of July most years, and the peak period for adult flight was mid-July, about 1 month later than in parts of Europe where winter wheat predominates. The timing of the emergence was similar from place to place and year to year. Females constituted 95% of insects caught in a flight trap. The first 10% and 50% of the flight occurred on 9 and 16 July, respectively, and the timing of the flight was not related to growing degree-days. In early August, mature larvae began dropping from wheat heads. The timing of infestation of spring wheat was variable among years because of differences in timing between midge flights and the susceptible heading stage of the crop. Nevertheless, the wheat midge flight usually coincided with the susceptible stage of the spring wheat crop.

In Holomelina immaculata (Reakirt) periodicity of male attraction to synthetic 2-methylheptadecane, the female-produced sex pheromone, is modified by temperature cues. In the field this response interval occurs from approximately sunset to about 4 h after sunset on a warm day and night (30° to 17 °C) and for the 2 h prior to sunset on a cool day and night (23° to 16 °C).

In laboratory studies at 24 °C female H. immaculata placed in continual scotophase have an endogenous calling rhythm, but they are apparently inhibited from calling by constant photophase. In 16:8 or 12:12 light–dark cycles at 24 °C calling occurs from the 2nd to the 6th hour of scotophase, whereas at 15 °C calling takes place from the initiation to the 5th hour of scotophase. The critical cues governing initiation of calling behaviour are lights-off or a temperature decrease cue, and a temperature decrease signal overrides the apparent inhibitory effect of continual photophase.

Observations on the feeding and mating behaviour of Rhamphomyia spp. in the high arctic are reported. In R. nigrita Zetterstedt the males catch their prey especially in the male swarms of mosquitoes, etc., and carry it to their specific swarming (mating) site, a station controlled by a typical visual marker. In the swarm the male responds to insects hovering above, by rising to within a few inches and then holding a steady distance for some moments. The upper insect, if a male, moves away; if a female, pairing soon takes place, the prey is transferred, and the female feeds on it during mating. Apparently the female obtains insect food in no other way. The prey is rather small, and insufficient for the completion of one ovarian cycle; and the swarming flight, with mating and prey transfer, occurs repeatedly.In R. ursinella Melander hunting and mating are accomplished on the ground. The prey is very small and mating is frequent. The species is virtually non-flying, and the specialized form of the male eye, on which mating in flight depends, is considerably reduced. Similar adaptations occur in other arctic Diptera. R. nigrita, in contrast, maintains fully the normal dependence on sustained flight.The general structure of mating behaviour in the specialized Empidinae (Rhamphomyia, Empis, Hilara) is discussed. As in many Empididae, and other Diptera, mating takes place at an assembly station controlled by a visually recognized swarm marker, and the response to the female is mediated by the large ommatidia of the upper part of the male eye. The "holding flight" however signifies an interposed courtship, or display of prey by the male to the female. In most species only the male captures prey (perhaps without feeding on it himself); the female does not hunt and obtains insect food only by transfer at mating. Courtship with transfer becomes a firmly established behavioural element, and persists even in species which use objects of no value as food (ritualization of prey).The original significance of the prey, on which its role as sign stimulus in mating is based, is its significance as food required by the female for ovarian maturation. When the prey is small in relation to the requirements of the female, the mating process, including the courtship and prey transfer, is repeated (ritualized) so as to provide the female with sufficient food. It is suggested that this ritualization would develop easily once insect prey had become established as the sign stimulus for mating; and could lead on to the sex differences in habits of hunting and feeding.

When male Anagasta kühniella (Zell.) were released in a wind tunnel downwind of a scenting female they flew upwind, but on losing the scent made crosswind casts and thus located the female. Downwind casts were rare. In still air males approached females from below. Visual stimuli seemed to induce mating behaviour.

A sex pheromone trap was studied as a quantitative sampling device in a biological monitoring scheme for codling moth populations in Michigan apple orchards. Factors influencing trap efficiency and the relationship of trap catch to adult moth density and the overall seasonal dynamics of L. pomonella are considered.

By correlating seasonal male moth catches to absolute infestation levels at harvest it was possible to indicate the density response of male moth catches in the pheromone trap (Sectar 1). Catch response was non-linear and the trap ceased to be indicative of higher infestation levels when accumulative catch exceeded about 100 moths/trap. Also, accumulative trap catches from the first few weeks of the season (before damage appeared) correlated well with eventual infestation levels indicating possible use of the pheromone trap as a predictive tool. Of the many factors influencing trap catch size the number of moth productive trees serviced by a trap (trap/tree ratio) was shown to be of critical importance.

Larvae of Hyphantria cunea Drury were reared on early, mid-season, and late foliage collected from the same apple trees. Survival was significantly lower on late foliage and the fecundity of the moths decreased from 604 in the early series to 128 in the late. Half the filial generation was reared under nutritional stress on a deficient synthetic diet and the other half on a very favorable host, speckled alder. Under both conditions there was a strong transmitted influence of parental food quality on the viability of the eggs and on the ability of first-instar larvae to become established on food. The progeny of the late series did not survive beyond this instar. When the filial generation was subjected to nutritional stress, the influence of parental food was apparent throughout the larval, pupal and adult stages, with progeny of the early series having higher survival than those of the mid-season series. However, when the filial generation hail very favorable food, there was no significant difference in survival rates subsequent to the larval establishment period.

The quality of foliage available to univoltine populations of H. cunea depends largely on temperature. Thus, in the development of population models for this species, temperature should be treated as a variable having not only direct effects on establishment and survival each season, but also indirect effects on the quality of the progeny in the following season.

Combinations of Bacillus thuringiensis Berliner subspecies kurstaki and Beauveria bassiana (Balsamo) Vuillimen formulated on granules were applied separately and in combination to field corn to suppress larval populations of the European corn borer, Ostrinia nubilalis (Hübner). Research was conducted in 2 separate years. Laboratory-reared O. nubilalis eggs or larvae were placed on the plant during either the whorl stage (V6) or the pollen-shedding stage (R1) to simulate first- and second-generation O. nubilalis oviposition periods, respectively. Efficacy was determined by measuring the length of European corn borer tunnels in the corn stalk at harvest time. In the 1st year, first generation, and second generation (of 2nd year) B. thuringiensis and B. bassiana alone and in combination caused significant reductions in tunneling compared with that in the check populations. There were no significant differences in tunneling between any treatments in the second-generation study of year 1. Bacillus thuringiensis and B. bassiana were independent of each other in their suppression of insects. Tunneling by the naturally occurring second-generation larvae (year 2) was recorded to determine if B. thuringiensis and B. bassiana applied in the V6 stage persisted in the plant. Pith samples were excised from nodal plates 7–10 of the corn stalk to determine the incidence of B. bassiana. There was a significant correlation (r = −0.376) (P≤0.05) between the occurrence of B. bassiana in the corn plant and tunneling by second-generation larvae. These data indicate that B. bassiana placed in the whorl of the corn plant may provide season-long suppression of O. nubilalis.

In 1948, the Mississagi region of northern Ontario was swept by a niajor conflagration that began on May 25 and which, because of dry weather conditions, was not brought under control until July 23. When the fire had been extinguished, it was found to have spread over 57 townships, or 281,388 acres in all. Officers of the Ontario Department of Lands and Forests estimated that approximately 75 per cent of the fire area bore mature stands of eastern white pine (Pinus strobus L.), red pine (P. resinosa Ait.) and jack pine (P. banksiana Lamb.). Salvage operations began immediately in an effort to save this vast amount of valuable timber.

The initiation of the pupal diapause of the apple maggot, Rhagoletis pomonella (Walsh), was found to be regulated by photoperiod and temperature. The stages of R. pomonella sensitive to these two regulatory factors were demonstrated to be the larva in the case of photoperiod and the larva and pupa in the case of temperature. Measurements with a highly sensitive photocell revealed that enough light passes through the skin and pulp of an apple to permit the response of the larvae to photoperiod to be direct. Diapause initiation was found to be independent of the effect of photoperiod or temperature on the adults and eggs and independent of the amount or type of larval food (apple or artificial).

Where larvae and pupae were reared at 28°C and a photoperiod of 17 or 19 hours of light per 24-hour day, 1% of the pupae completed development in 23 days, 50% in 28 days, 75% in 30 days, and 100% in 64 days. These were the only regimes tested at which there was 100% non-diapause development, a finding which is directly applicable to continuous laboratory rearing of the apple maggot. Irrespective of temperature, diapause was induced in more than 50% of the pupae at a larval photoperiod of 11 hours. Even where larval photoperiod was favorable for 100% non-diapause development (17 or 19 hr), diapause was induced in more than 25% of the pupae if larval and pupal development occurred at 23°C and in a larger percentage if larval and pupal development occurred at 19°C.

These findings are helpful in elucidating those conditions in nature under which a second generation of R. pomonella occurs.