Certain aspects of the reproductive ability of sterilized and unsterilized tobacco budworms, Heliothis virescens (F.), of a laboratory strain and a field strain, tested as single pairs, were studied; special attention was given to those females of pairs that mated but did not reproduce and to the distribution of sperm in the reproductive tract at various times after mating. Most of the sperm from the first two successful matings reached the spermatheca, but after three or more matings, substantial amounts were also present in the bursa copulatrix and(or) seminal duct. Ca. 18% and 35% of the unsterilized laboratory strain and field strain pairs, respectively, did not reproduce; 4.6% and 20.6%, respectively, locked or failed to mate. The percentage of mated pairs was reduced by the presence of a field strain female in crosses of the strains. Exposure to irradiation and chemosterilants reduced fertility but had little effect on mating frequency in either strain. Percentage egg hatch was the same for the untreated insects of both strains.

Acephate (Orthene 75S) was applied to Douglas-fir (Pseudotsuga menziesii Mirbl. [Franco]) in spring 1976 to determine its efficacy for protecting current year’s foliage from western spruce budworm (Choristoneura occidentalis Freeman). Results showed budworm mortality for both treatments exceeded the checks by at least 91% at all sample periods. A significant degree of foliage protection was also achieved as measured by mean twig length and mean number of missing needles per twig. Samples of new growth were analyzed for residues of acephate and methamidophos (an active metabolite of acephate) by gas-liquid chromatography. Results showed that high levels of insecticide persisted for about 10 days, then dropped over a 5-day period to lower levels for the rest of the study, about 35 days.

Attractant traps, such as Pherocon ICPY®-MAGO trap and Pherocon®-AM Standard trap, were effective in monitoring emergence of the western cherry fruit fly, Rhagoletis indifferens Curran. Among the aerial traps tested, ICPY-MAGO, Pherocon-AM Standard, and Saturn yellow colored rectangles and spheres were equally effective. The ammonium carbonate traps were significantly inferior. A management program that utilized aerial traps as monitoring devices reduced the amount of spraying from 20 to 100%, depending on the fly population in the orchard, and resulted in a substantial saving of spray costs.

Glaucosarcophaga knabi Townsend is a synonym of T. albicans (Wiedemann), a highly variable species; a comparative study of specimens from South America and Mexico was made.

Aerially sprayed fenitrothion (0.21 kg/ha) caused mortalities from 100% among experimentally caged bees in exposed habitats to 47% in cages placed under dense forest canopy. Bumble bees found foraging in sprayed areas during the days immediately following the spray suffered significantly higher subsequent mortality than those in unsprayed areas.

Long-term effects were investigated by comparing late summer Bombus population densities among sites representing various spray histories. For all species combined, abundances in unsprayed areas averaged 3 times higher than in fenitrothion treated areas. Population recovery appeared to be complete within a few years after discontinuation of spraying.

Foraging performance by laboratory reared colonies was significantly higher in sprayed areas with reduced bee populations than in a control area, possibly because of relaxation of competitive stress. The diversity of plant species used for pollen collection was nearly twice as great in the control as compared with sprayed areas, suggesting that the effect of fenitrothion spraying on cross-pollination may be greatest for plants which are subdominant in the hierarchy of bee preference In one such plant, red clover, reduced seed-set was demonstrated.

Female adults of two new species of Trisetacus infesting berries of junipers are described, T. neoquadrisetus from Rocky Mountain juniper and T. batonrougei from eastern red cedar, with remarks on the identity of eriophyoid mites living in juniper berries in North America.

Adults of two new species of Trisetacus infesting foliage of Cupressaceae are described, T. distinctus from eastern white cedar based on females and males, and T. macrocarpae from Monterey cypress based on females The possible significance of host plant sympatry of morphological species of Trisetacus is discussed briefly.

Factors affecting the winter survival of temperate-zone insects are reviewed. Certain species suffer high winter mortality especially in cold years, or in years with below normal amounts of insulating snow.

Survival depends on the choice of winter microhabitat and on cold-hardiness, but also on biological features that have not previously been emphasized. These include behaviour that results in placement of overwintering eggs in less severe sites and manufacture of cocoons or other structures that retard inoculation by ice, or desiccation. The possible role of habitat heterogeneity in facilitating population survival is stressed.

Microhabitats are characterized mainly with respect to temperature. They differ markedly among geographic areas and not only in midwinter conditions (including the extent of variation), but also in the time at which entry to the microhabitat in fall is necessary to avoid the risk of frost. The cues that govern entry into these microhabitats include negative phototaxis in many species but have not been subjected to quantitative analysis. Deeper layers are warmer in winter but warm up more slowly in spring and therefore some species, especially in arctic habitats where rapid vernal development is advantageous because the season is short, overwinter in superficial or insolated sites.

Supposed mechanisms of cold- and freezing-injury and its avoidance are reviewed. There are several theories of freezing-injury: many modem theories focus on damage to the cell membrane, apparently caused by changes in cell volume induced during freezing. Injury is avoided by suppression of haemolymph nucleators (enhancing supercooling); or by a variety of methods, especially those involving solutes, minimising damage to frozen tissues. Among these solutes, the prevalence of glycerol in overwintering insects is not unexpected since glycerol is a normal metabolite in animals and can play several possible roles in cryoprotection.

Cold-hardiness is metabolically costly because of these solute adjustments. The cold-hardiness of a taxon depends partly on climatic history during its evolution. Faunal composition at the highest latitudes reflects this dependence.

The winter survival of many high-latitude insects varies rather widely from year to year; but the many detailed studies on cold-hardiness that have been made in the laboratory have seldom been related to natural mortality.

The overwintering stage depends partly on the taxon. It is often fixed within a genus, but less closely within higher taxa. Proportionately more species overwinter as larvae at higher latitudes, especially when the life cycle lasts more than one year. Habitat also influences the overwintering stage: aquatic species generally overwinter as larvae, although species of temporary pools frequently overwinter as eggs. Overwintering in more than one stage is not common.

This review suggests that winter survival of a group depends on latitude (or its climatic equivalent), habitat, and evolutionary history. It might therefore be especially useful to compare cold-hardiness, developmental rates, control of the life cycle and other features among species at the same latitude from each extreme of a series, that contrasts cold-hardy groups in stable habitats (such as Chironomidae) with aerial or vegetation dwelling groups that are not cold-hardy (such as Orthoptera). Future study of winter survival also demands more ecological data (overwintering stage, microhabitat, and conditions experienced there) for a larger sample of the fauna, and the simultaneous measurement of cold-hardiness.

Two new species of Epiclerus Haliday from North America and the Greater Antilles are described and illustrated, these being the first records of the family Tetracampidae native to the New World.

Within-tree colonization by Dendroctonus frontalis infesting loblolly pine, Pinus taeda L., was investigated. Two components of the colonization process were studied: the establishment of attacking adults (ATK) and the ensuing construction of egg galleries (GL). Data on the two variables were taken from standing trees beginning at the time of initial attack and continuing for 14 consecutive days.

The spatial and temporal sequence of ATK was described for 1.5 m intervals along the infested bole for the duration of the process. A three parameter nonlinear function was used to describe the data. The pattern of attack was also described as an average process for the entire tree using the same model. A frequency histogram encompassing the range in variation for peak ATK from 134 trees was prepared to provide starting values for simulation purposes.

The spatial and temporal sequence of GL construction was described using essentially the same approach as employed for ATK. The modeling process was complicated by loss or obscuring of GL from the radiograph by omission errors and foraging by Monochamus spp. and other associates. GL construction was also described as an average function for the entire tree and the rate of GL construction was defined. A frequency histogram of peak GL was prepared from data on 54 trees for use in selecting starting values for simulation purposes.

Numerical relationships between ATK and GL were defined by combining the data on ATK and cumulative expected GL.