Mating frequency and behavior of five color-coded adults of each sex of Trypodendron lineatum (Olivier) were observed for 1 hour periods in petri dish arenas. Mating activity was evaluated by recording each incident in which a male assumed the "precopulatory" position on a female for a minimum of 10 seconds. Newly emerged brood adults mated with very low frequency. The mating activity of revived overwintering beetles increased throughout the winter. In February there was a sudden rise in activity to an intensity approaching that of sexually active "spring" populations of March and April. This pattern, as well as the recovery of locomotion upon warming throughout the winter, provides evidence that overwintering populations undergo only a reproductive diapause, or hibernation. Mating activity of excavating parents fell to one-half that of spring beetles within 2 weeks of host invasion and declined further after 4 weeks. Parents that had recently emerged from brood logs had negligible mating activity. Flight was not an essential prerequisite to mating. There was no prolonged delay between initial contact of the sexes and mounting, and no observable courtship. Behaviorally, the male was the aggressive partner; the female was passive and nonresisting. Multiple matings by both sexes, with the same or different partners, and mounting of mating couples and other males by males were observed. The average duration of mounting was 1.75 minutes and, when copulation occurred, 3.35 minutes; dissections showed that this period was sufficient for insemination. Pronounced reduction of mounting and copulation activity occurred within 30 to 40 minutes of initial contact with the opposite sex. Mating frequency depended primarily on the maturity and vigor of the male, although the maturity of females had a slight effect.

The principal injurious species to commercially-grown flue-cured tobacco in Nova Scotia was the dark-sided cutworm, Euxoa messoria Harr. A trace of the black cutworm, Agrotis ipsilon Hufn., was found in one field. The variegated cutworm, Peridroma saucia Hbn., caused minor damage in September. Other species reared from field-collected larvae, and bait and light trap catches, included: yellow-headed cutworm, Apamea amputatrix Fitch; armyworm, Pseudaletia unipuncta Haw.; Amphipyra tragopoginis L.; W-marked cutworm, Spaelotis clandestina Harr.; and the glassy cutworm, Crymodes devastator Brace.

Cutworm larvae damaged young tobacco plants during June through mid-July. The largest infestation encountered during 1971, near the margin of a field, killed 5% and injured 20% of the young plants. Infestations in other fields injured 1 to 3% of the plants, with higher incidences near the borders. A seasonal total of 0.024 cutworm larva injured 0.24 tobacco plant/m2 and destroyed 5 to 10% of the injured plants in experimental tobacco field plots planted in a 4-year-old rye field.

Tobacco trap crop m2 microplots in a rye field attracted 20 to 50 times as many cutworm larvae and had 25 to 40 more plants injured than comparable areas of an adjoining tobacco field. The largest microplot infestation in six fields tested was 1.8 larvae injuring 7.4 plants. The average microplot infestation of 0.5 larva injured 5.6 plants.

The identity of Leucopis (Leucopis) argenticollis Zetterstedt, an adelgid predator described from Sweden, is established and a lectotype is designated for it; L. orbitalis Malloch, described from Illinois is placed as a synonym of it. Another species (predator of the mealy plum aphid) that was formerly confused with argenticollis, is described as Leucopis (Leucopis) conciliata McAlpine and Tanasijtshuk, new species. Both species are shown to be holarctic and are treated from the standpoints of adult and larval morphology, biology, and distribution. The paper contains 33 figures.

Coeloides brunneri Viereck females were interrupted in the act of oviposition into Douglas-fir logs and the oviposition site marked. Thermistor probe temperature readings revealed that C. brunneri invariably oviposited over "hotspots" on the bark surface associated with subcortical Douglas-fir beetle larvae. Artificial hotspots were created by placing heated resistance wire probes underneath the bark of an uninfested log. In the absence of all other stimuli, these artificial hotspots induced the parasites to exhibit normal search behavior and to make ovipositional probes, the final phase of host finding. These data augment observations of antennal posture of a searching parasite and the discovery of a possible infrared radiation receptor on the antennae, and support the argument that C. brunneri locates its host through perception of infrared radiation.

The larch sawfly, Pristiphora erichsonii (Hartig), has exhibited several distinctive population patterns in different parts of its Holarctic distribution and during different periods of time in some geographic areas. These patterns include a latent type, where the larch sawfly is never a pest, a permanent type, which causes severe damage, and several temporary types characterized by periodic outbreaks. The different population patterns are associated with differences in the life systems of the populations: the stable latent type with a diverse environment and a rich parasite complex; the stable permanent type with an impoverished parasite complex, interactions with food availability and no effective specific parasites; and the temporary type with an intermediate parasite complex which includes one very effective specific larval parasite. Thus, population stability is related to either maximal or minimal diversity in numbers of parasite species and instability to intermediate levels. The comparison of population patterns and life systems provides a guide to the development of biological control programs.

Spruce budworm weights, either of individuals or of population averages, when related to time, provide more precise measures of development than the usually used time from hibernacula to pupation or to eclosion. For determining or predicting the development stage of field populations, average weights are a more precise alternative to time-consuming, instar determinations. Larvae feed only about 10% of the time, in darkness or light, and the pupal dry weight is 20–24% of the dry weight of artificial diet consumed. Growth curves for laboratory individuals and field populations are described.

The spider fauna of three hayfields and their margins in Nova Scotia was sampled by means of pitfall traps from May to October, 1960. Eleven families were represented and comprised 35 genera and 55 species. Specimens of the genus Pardosa were trapped in greatest numbers.

Reciprocal field tests of attraction between populations of Ips pini (Say) from California, Idaho, and New York disclosed geographic variation in pheromone systems. These differences reside both in pheromone production and reception. However, it is unknown whether variation in the pheromone bouquets is qualitative, quantitative, or both.

In New York, both sexes responded in higher numbers to their own pheromone than that produced by California or Idaho males. In California, beetles of both sexes discriminated against New York, but in Idaho only females made this distinction. In both California and Idaho, the local population showed a slight preference for the pheromone produced by Idaho males over that produced by California males.

The predator Enoclerus lecontei (Wolc.) demonstrated a four-fold preference for attractants produced by males from New York over those produced by beetles from California and Idaho. The parasitoid Tomicobia tibialis Ashmead showed the opposite trend.

There is no evidence that geographic variation in the pheromones produced by I. pini is sufficient to enforce breeding isolation between adjacent populations. However, these results dramatize the necessity of considering pheromonal variability in programs applying pheromones for the survey and control of widely distributed pests.

Three new species of aphids are described from collections made on Mt. Sutep in northwest Thailand: Cinara khasyae new species; Greenidea (Trichosiphum) chiengmaiensis new species; and Macrosiphum (Sitobion) yongyooti new species. The status of Greenidea (Trichosiphum) siamensis Takahashi is changed from variety to species.

Two types of sensory hairs on the tarsus of the spruce budworm, Choristoneura fumiferana (Clem.), are described using scanning electron microscopical and histological techniques.

Diapause in Wyeomyia smithii (Coquillett) was shown to be a function of photoperiod, and independent of temperature. The critical daylength for a population from Pinawa, Man., was 15 hr light per diem. The photoperiodic cues are monitored by the early instars, with diapause being expressed in the third instar. Development is also limited by temperatures below 15 °C even when the critical daylength is exceeded.

Survival at low and subzero temperatures is aided by the diapause state. However, larvae are unable to withstand extended periods of subzero temperatures, even in the diapause condition. At −5 °C, 60% mortality occurred after 8 weeks under laboratory conditions. In the field, where ground temperatures averaged −3.7 °C during the five coldest months, larval mortality averaged 45% after four winter months.

Once diapause is established, larvae consume very little food. Diapause larvae appear to be as active as non-diapause larvae, and also appear to be feeding constantly. However, the amount of food ingested is negligible compared to non-diapause larvae.

Salticid spiders of the genus Continusa were present in 61% of the nests of dolichoderine ants (Tapinoma melanocephalum (Fabricius)) which build their nests on the undersides of leaves in the lower forest canopy on the Osa peninsula of Costa Rica. Cutting and displacement of the supporting leaves caused abandonment of 80% of the nests within 4 days and experiments carried out by marking and displacing the spider indicated their tenacity to the ant nest. T. melanocephalum nests which contained spiders were more successful in terms of the brood to adult ratio.

A method for weekly production in excess of 100,000 second-instar larvae of the spruce budworm, Choristoneura jumiferana (Clem.), is described. It depends on adherence to specific regimes of physical conditions and manipulation for the different immature stages. Standard, easily obtained utensils and materials are used in the rearing technique.

Viable egg masses were obtained from adult caddisflies during revival from CO2 anesthetization. The egg masses were maintained in aerated water and the eggs hatched in 1 or 2 days. Larvae were supplied various food sources (bacteria, algae, and invertebrates) and case building materials. This technique permits casemaking and other aspects of larval behavior to be observed, and allows for complete description of associated larvae.

The effects on the house fly, Musca domestica (L.), of a series of cis-9 alkenes containing 19–25 carbon atoms were investigated. An unexpectedly wide spectrum of these homologous hydrocarbons showed biological activity. Synergism and interesting changes in behavioural responses (excitement, mating, and orientation) varying with structure and concentration were observed.

Comparative gas chromatographic analyses of volatiles generated by Ips indicate the presence of cis- and trans-verbenol in hindguts of the 12 species investigated. The biosynthesis of verbenol does not require feeding, but instead results from the insect’s contact with oleoresin. Ipsdienol is the most frequently occurring pheromone in Ips species after feeding. Aggregation of these bark beetles appears to be regulated by two distinct functional types of pheromones, i.e. contact pheromones, produced and/or released upon contact with new host material, and frass pheromones, which require actual feeding in the new host’s tissues. The aggregation of aggressive bark beetle species seems to be largely dependent on contact pheromones, whereas the host’s susceptibility to feeding is indicated by the release of frass pheromones.

Within white spruce stands near Fairbanks, Alaska, and on the Kenai Peninsula, Alaska, Dendroctonus rufipennis, Ips spp., and Trypodendron lineatum disperse in late May and early June; other scolytids fly during June and July. Flight in interior Alaska precedes by about 2 weeks that on the Kenai Peninsula. Mean daily temperatures during spring and early summer are generally warmer in the interior than in coastal areas. There was a large increase in the total number of beetles in a thinned area, mostly of Dryocoetes affaber.

Deposits of the nuclear-polyhedrosis virus of Trichoplusia ni (Hübner) and of the granulosis virus of Pieris rapae (Linnaeus) were largely inactivated within 10 days after sprays were applied to field plots. Deposits on plants retained in a growth room or in a greenhouse were inactivated but more slowly than those exposed to direct sunlight. Deposits on plants kept in the dark lost little activity indicating that exposure to light was responsible for inactivation.

Activity of deposits of the viruses was extended substantially by addition of protectant materials to the sprays. The addition of charcoal mixed with skim milk powder, egg albumen, or brewer’s yeast resulted in a 3-fold increase in the period over which an LD50 of virus was maintained on the plants.

The Poisson and the negative binomial series, Taylor’s power law, and Morisita’s Iδ-index were used to interpret the dispersion of field counts of the immature stages of Hypera postica (Gyll.) on alfalfa. The data conformed consistently to an overdispersed distribution. Transformations are offered for stabilizing the variance of field counts.