Sex pheromone-mediated mating disruption was used to control the grape berry moth, Endopiza viteana (Clemens) (Lepidoptera: Tortricidae), at two farms in the Niagara peninsula, Ontario, during three consecutive growing seasons, 1989 through 1991, to determine if earlier observed between-generation increases in the percentage of infested grape clusters would continue between growing seasons. The relative performance of the pheromone treatment was assessed by comparing the percentage of infested clusters in the pheromone-treated plot with the percentage of infested clusters in an adjacent, insecticide-treated plot. Although the percentage of infested clusters increased from 1.7- to 56.5-fold between successive generations in the pheromone-treated plots, there was no indication that the level of infestation at harvest affected the level of infestation the following spring. At one farm, the percentage of infested clusters was greater in the pheromone-treated than in the insecticide-treated plot during 1989, but during 1990 and 1991, the level of infestation was similar in the two plots. At the other farm, the level of infestation was from 2- to 3-fold greater in the insecticide-treated than in the pheromone-treated plot.

The genus Frontiniella Townsend is transferred from the Eryciini to the Goniini, based on the production of microtype eggs in adult females. Frontiniella is known only from the Nearctic Region and the northern extreme of the Neotropical Region. Eufrontina Brooks is newly synonymized with Frontiniella and all species formerly placed in that genus are transferred to Frontiniella. Frontiniella is hypothesized to be monophyletic based on two derived character states: long hairs on the male surstylus, and elongate posterior spiracles on the puparium. Two species groups are recognized, one with six species and the other with four: the parancilla-group with F. parancilla Townsend, F. incarcerata sp.nov. (type-locality Hwy. 366, Graham Co., Arizona, USA), F. spectabilis (Aldrich) (new combination), F. surstylata sp.nov. (type-locality near Olustee, Florida, USA), F. jorgenseni sp.nov. (type-locality 20 miles northwest of Kenna, New Mexico, USA), and F. ethniae (Brooks) (new combination); and the festinans-group with F. festinans (Aldrich and Webber), F. apache sp.nov. (type-locality Sulphur Draw, Chiricahua Mts., Arizona, USA), F. mitis (Curran), and F. regilla (Reinhard). This revision includes a key to the 10 known species of Frontiniella, a description of each species (including puparium where known), maps of species distributions, an annotated list of hosts (including corrections to previously published records and additions from material examined), and illustrations of taxonomically useful features.

Resistance of horn fly, Haematobia irritans (L.), to fenvalerate and permethrin was evaluated in Manitoba from 1987 to 1989. The number of resistant populations and the intensity of resistance increased during the period. In 1987, resistant flies were observed on three of 18 herds sampled. Resistance, determined by comparison with a susceptible strain at the LC50, was less than 6-fold for fenvalerate and 3-fold for permethrin except for one population whose resistance was 14-fold for permethrin. In 1988, resistant flies were observed on six of 26 herds sampled. Resistance ranged from 0.03- to 38-fold for fenvalerate and 0.1- to over 100-fold for permethrin. In 1989, resistant flies were found on 10 of 22 herds sampled. Resistance ranged from 1- to 62-fold for fenvalerate and 0.8- to over 100-fold for permethrin. Resistant populations were interspersed among susceptible ones.

A simple, inexpensive, permanent method for individually marking Colorado potato beetle is presented. The method consists of puncturing the elytra within the cream-colored longitudinal bands using a minuten nadeln; the wound response produces intense melanization at the point of puncture. Division of a band into three zones, each potentially receiving a dot, produces an octal digit. If all eight bands are employed, more than 16 million beetles can be uniquely marked. No significant survival effects of marking were seen in teneral, post-teneral, or post-diapause adult beetles. Propensity to fly in mid-summer beetles was generally unaffected by marking. Probabilities of mismarking and misreading are negligible if sufficient care is employed.

The variation in response to fungal inoculation and sterile wounding within and among Pinus taeda L. was evaluated. The mean fungal-induced lesion size among the 20 trees sampled was 105.8 mm (coefficient of variation of 49.19), compared with a mean lesion size of 19.4 mm (coefficient of variation of 36.40) for the sterile control treatment. Mean lesion size for the fungal inoculation of individual trees ranged from 61 to 192 mm with a range in variances from 10 368.48 to 166.64, and the mean lesion size produced in response to sterile wounding varied from 16 to 26 mm with a range in variances from 254.28 to 0.35. The variance in response to the fungal treatment was on average 16.39-fold greater than the mean compared with only 1.97-fold greater than the mean for the control. There was no relationship between size of responses to either treatment and the position of the sample site on the tree. We suggest that intra-tree variation of the kind demonstrated in earlier studies for the chemical constituents and for physical size of the tree response to invasion may make it very difficult for arriving beetles to assess actual tree susceptibility or suitability for colonization. This may be critical as a component of tree defense in this system where successful reproduction by the insect is dependent on death of the host tree.

The ambrosia beetle Gnathotrichus retusus (LeConte) (Coleoptera: Scolytidae) is primarily univoltine. The development of brood from eggs to adult took a minimum of 40 days in Douglas-fir logs. Brood production was proportional to gallery length. Boring activities shifted from shallow sapwood to deep sapwood over time. Gallery abandonments were mainly made by females on warm days in June and July.Gnathotrichus retusus can use both Douglas-fir and western hemlock stumps equally well for brood production. Brood emergence began in late April, peaked in late May, and ceased, with rare exceptions, in late June. The seasonal flight began in late April and had one major peak in June, with occasional catches through October when the weekly mean maximum temperature dropped below 15 °C. Brood emergence, seasonal flight, and the sex ratios of captured beetles varied with temperature. Diurnal flight showed a small peak in morning and a large peak at dusk, probably entrained mainly by light intensity and also influenced by temperature and relative humidity.

Patterns of locomotion of arctiid caterpillars, Diacrisia virginica Fabr., deprived of all external chemosensory organs were recorded in a field where there was patchy distribution of two of the most favored food plants, Plantago major L. and Taraxacum officinale Walker, on a background of grass and mixed forbs. Each track traced in the field was retraced on a digitizing tablet from its point of origin in the center of a circle of 30 cm radius to the circumference. The length of the path was a measure of tortuosity. The patterns of paths followed by normal, antennectomized, maxillectomized, and antennectomized + maxillectomized larvae were compared. No differences in meander were found. The ability of larvae of each class to locate, discriminate among, and feed upon food plants was tested in field-plot tests and cafeteria tests. Different degrees of chemosensory deprivation did not affect ability to locate and begin feeding on plants but did impair ability to discriminate among species. Execution of normal patterns of meandering by chemosensorily deprived larvae and successful encounters with food plants support the hypothesis that food-related search behavior by this species of caterpillar is neither initiated nor steered by chemical stimuli provided by food plants.

In southern Alberta, alfalfa seed yields are related to the amount of pollination that occurs before mid-August by the major pollinator, the alfalfa leafcutter bee, Megachile rotundata (F.). Cutting the leaves causes wear to the bee’s mandibular teeth and could reduce the bee’s pollination efficiency and, ultimately, seed production. A method is described for employing digital image analysis to measure mandibular tooth areas for alfalfa leafcutter bees. The method is relatively quick and has high precision and repeatability. This method was used to measure the area of the mandibular teeth for leafcutter bees, before and after foraging in alfalfa seed fields, to evaluate differences in mandibular wear. Analysis of mandibles showed that foraging leafcutter bees collected in late July had significantly smaller tooth areas than pre-foraging bees collected prior to release in June.

The sensory structures of the cephalic segment of first- and third-instar Arachnidomyia aldrichi (Parker) (Diptera: Sarcophagidae) larvae were examined by scanning electron microscopy. Larvae were prepared by methanol freeze substitution, which effectively preserved the structure of these membranous specimens. Sensilla of first and third instars are described and compared with respect to differences in the sensory requirements of these instars. Sensilla numbers and types were similar in both instars, although the sensilla of third instars were larger than those of first instars. None of the external sensory structures was unique to one or the other instar. The cephalic sensory structures of A. aldrichi are also similar in arrangement and structure to those reported for other saprophagous and herbivorous muscomorph dipteran larvae.

Mass storage of honey bee (Apis mellifera L.) queens over the winter was investigated in colony banks, with each queen held in her own cage within a colony. The major treatments included: (I) a single queen wintered in a small nucleus colony (control); and colony banks with 24 or 48 queens, each held individually in (II) screen cages that prevented workers from entering the cage, but allowed access for queen tending, (III) queen-excluder cages (queen-excluder material has openings of about 55 mm that prevent the larger queen but not the smaller workers from passing through the material), or (IV) screen cages until January and subsequent transfer to mini-nuclei until late March. Queens held in excluder cages showed poor survival in all 3 years of testing, and this system was not viable for commercial use; survival for any 1 year, or any excluder treatment, was never greater than 25%. In contrast, a 2-year average of 60% queen survival was found for queens that were stored in individual screened wooden cages within queenless colony banks. We found no differences in survival of banked queens that were moved between colonies monthly and those that remained in the same colony for 6 months. The success of these systems required the (a) preparation of colony banks that contained large numbers of adult workers produced by maintaining colonies with two queens during the previous summer, (b) removal of laying queen(s) during the storage period, (c) feeding of colonies well, and (d) insulation of colonies in groups of four, to preserve heat and reduce worker clustering in the winter. Surviving queens from winter storage systems were virtually identical in quality and colony performance to control queens the subsequent season. The annual profit for a commercial beekeeper who does his/her own labour for storage and hires workers for queen production was calculated as $16,625 when 4800 queens are stored over the winter, and sold for $10 each in the spring. Thus, mass queen storage using our successful systems is both biologically and economically viable.

Workers of social insects are members of colonies that survive and reproduce together. Therefore, the behavioral activities of individual workers should be integrated with colony state. We here summarize and discuss the relationship between colony state and foraging behavior of individual workers under the provisional assumption that the colony is a unit. We argue that colony state can be described by a number of variables that should relate to fitness components in order to be meaningful. Among the possible candidates, colony population size seems to have an overriding importance in many respects, as shown by its relation to fitness components such as survival probability and reproductive performance. Other important variables include colony demography, i.e. caste or size distributions, nutritional status, or queen number. Each of these variables has been shown to affect fitness components; however, the evidence is rather scanty. We also discuss the evidence that variation in colony state variables relates to variation in individual worker behavior. Nutritional status (i.e. low or high levels of food stores) and colony size have been shown repeatedly to affect individual behavior. However, most of the evidence comes from the honey bee. Some studies suggest that behavioral responses are hierarchically structured. More work needs to be done to investigate the actual mechanisms of integration of individual behavior with colony state. Some knowledge has accumulated about the processes that govern recruitment to food sources. We conclude this review by discussing some concepts and problems for further research. These include the concept of a preferred colony state to which the colony should return after disturbance through the behavioral activities of the workers. Further theoretical elaboration and empirical investigations may help to elucidate whether this concept is useful and necessary. A largely neglected issue concerns the number versus effort problem, i.e. whether individuals should work harder or more workers should be allocated to a task that is in demand. We propose a simple scenario that suggests testable predictions. Finally, we discuss how colony state, individual work load, and the dependence of worker mortality rate on activity level may interact to generate different short-term foraging strategies that workers should adopt.

The predatory gall midge, Aphidoletes aphidimyza (Rondani 1847), is a biological control agent used worldwide to control aphids. Mass-production methods are well established in Canada, the Netherlands, England, Germany, Finland, and the former U.S.S.R. (cf. van Leiburg and Ramakers 1984). In early March 1991, after 6 years of massproduction of A. aphidimyza on a rapidly increasing scale, two minute adult hymenopterous parasitoids were observed eclosing from a sample of pupae at a commercial insectary in British Columbia. It is likely that the founding parasitoid individual(s) entered the greenhouse before winter, as parasitoids appeared too early in the year to have entered from outdoors at that time.

Azadirachtin (AZA) is the principal insecticidal compound occurring in the oil of neem [Azadirachta indica (Juss.)] seed. Although many studies have been published (Schmutterer 1990) regarding the effects of AZA on herbivorous insects, little is known of the impact of this compound on the natural enemies of herbivores. Beckage et al. (1988) investigated the effects of injected AZA on Cotesia congregata (FAY) (Braconidae), a parasitoid of Manduca sexta (L.). Parasitoid development was retarded when injections of 2.5–10 μg AZA were administered to the host larva prior to the wasp's first larval ecdysis. The development of new neem-based insecticides in North America (Isman et al. 1991) has prompted the investigation of the effects of AZA on the natural enemies of pest insects that have ingested sublethal doses of the active compound. Our laboratory study was carried out with the ichneumonid parasitoid, Diadegma terebrans (Gravenhorst), and its host, the European corn borer, Ostrinia nubilalis (Hubner). AZA (>95% purity) for this study was extracted as described previously (Xie et al. 1991) from seeds collected in India.

Large infestations of the mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Scolytidae), reportedly arise from small, spot infestations that expand, multiply, and eventually coalesce (Safranyik et al. 1974). If these spot infestations can be located and eradicated, the development of outbreaks may be delayed, or even precluded. The principal means of eradication of such spots in forests of lodgepole pine, Pinus contorta var. latifolia Engelmann, in British Columbia is single tree disposal (B.C. Ministry of Forests 1987). This may be accomplished by treating with an arsenical herbicide within 3–4 weeks after attack, cutting, bucking, piling, and burning trees before brood emergence, or extraction and processing of brood trees before emergence.