Parasitoid species attacking sparse, endemic populations of Choristoneura occidentalis Freeman and C. retiniana (Walsingham) are reported from 2 years of host collections at seven sites across southern Oregon. Results are compared with rearings from epidemic populations either from the same region or the same plot. Collections were designed to allow quantitative estimation of host density. Most of the parasitoid species present during epidemics across North America were recovered from the endemic and epidemic populations studied. The major difference is that at endemic host densities Glypta fumiferanae (Viereck) (Ichneumonidae) is rare to absent, whereas ichneumonids of the tribe Campoplegini, especially Tranosema (= Diadegma) interruptum (Ashmead), are common. This is the reverse of the situation at epidemic densities and consistent with results reported from eastern North America. It is suggested that the observed shift in the parasite complex with budworm density has the potential for predicting population trends.

The influence of temperature and larval density on the flight performance of Diabrotica virgifera virgifera LeConte was quantified in the laboratory using a tethered flight system. Temperature had a significant influence on trivial flight performance in males and in both young (5 day) and older (25 day) females. The proportion of beetles undertaking trivial flight, and trivial flight duration and frequency peaked at temperatures around 20–25°C. Generally, males were more active than females at lower temperatures. Female beetles did not display sustained flight behavior at 15 or 35°C and males did not undertake sustained flight at 30 or 35°C. Sustained flight duration was unaffected by temperature. Rearing larvae at different densities influenced adult size but had only subtle effects on adult flight performance. Larval density significantly influenced trivial flight duration and frequency of older females and flight frequency of males but had no effect on young females. In general, trivial flight performance peaked when larvae were reared at moderate densities (500–750 per primary rearing container). In young females the propensity for sustained flight, but not flight duration, declined with increasing larval density.

Comparisons of selected biological attributes were made to establish a phylogenetic basis for the classification of the Cicindela splendida Hentz group taxa. Recognized members of the group, C. splendida, C. limbalis Klug, and C. denverensis Casey, are spring-fall species, and northern populations emerge later during spring than southern populations. Despite differences in time of peak abundance, the three species overlap in time and space. The absence of large numbers of hybrids of these three species suggests that although closely related, their adults can distinguish from each other, and thus their rank as species should be retained.

Comparison of geographical distribution of these species with that of dominant soil types revealed that they had similar soil preferences. The geographical distribution of all three species was smaller than the range of their preferred soil types, probably because of the same factors that influence their local distributions.

Morphometric analyses of these species revealed a closer similarity between C. splendida and C. limbalis. In both sexes elytral pattern, percentage maculation, elytral colour, and non-sensory setae number collectively distinguish these species from each other, whereas body measurements, body ratios, sensory setae, and labral setae collectively fail to distinguish them.

Based on plesiomorph/apomorph character polarization, and the C. purpurea Olivier group as outgroup, it was determined that C. denverensis represents an early lineage of the C. splendida group, whereas C. splendida and C. limbalis are more recent sister species.

The ancestor of the C. splendida group probably evolved during late stages of the Tertiary Period as a North American resident and was a continental, riparian, cool-temperate form that ranged across Canada and northeastern and central United States. Extant forms speciated during the late Pleistocene as a result of spatial fragmentation of populations, isolation, and adaptation during glacial and interglacial periods.

Six systemic and two nonsystemic granular insecticides were evaluated by application in the furrow at planting for control of overwintered tuber flea beetles, Epitrix tuberis Gentner. Studies were conducted from 1986 to 1988 in three soil types in the lower Fraser Valley of British Columbia. Of the registered systemic insecticides tested, phorate and aldicarb gave rapid and consistent control of overwintered adults released on the foliage 24–30 days after planting, whereas disulfoton and carbofuran were either less effective or more variable in their control. Terbufos and cloethocarb, not registered for use on potatoes, gave control of adult beetles similar to that of phorate and aldicarb. Mortality of overwintered generation adults resulting from these systemic insecticides was correlated with numbers of beetles emerging in the summer adult generation. Neither fonofos nor chlorpyrifos, the nonsystemic granular insecticides, gave effective control of overwintered flea beetles. Only fonofos significantly reduced the emergence of beetles of the summer generation, but the control was inconsistent between years. When beetles were released on the foliage 56 and 65 days after planting, the fewest beetles emerged from the phorate and terbufos plots. All treatments were less effective in highly organic soils than in mineral soils. The advantages of using granular systemic insecticides for controlling overwintered E. tuberis, and strategies for improving control in association with integrated pest management programs are discussed.

The mullein bug, Campylomma verbasci (Meyer), was successfully established on eggplant cv. “Black Beauty” using the twospotted spider mite, Tetranychus urticae Koch, as a source of prey for early instars. Colony-raised teneral females lived 17.4±0.8 days (mean±SE) at 25°C, and their progeny averaged 6.7±0.6 nymphs per 48-h oviposition period (range 0–36). Fecundity peaked during days 6–10 and declined steadily beyond day 16. Over their lifespans, females produced eggs that hatched into 37.5±8.2 nymphs (range 2–184). Eggs from a 24-h oviposition period required from 7.2±0.1 days at 27°C to 13.0±0.2 days at 20°C for 100% hatch. An estimated developmental threshold of 9.5°C (r2 = 0.50) was obtained using the equation: rate of development = −0.075 + 0.008 (temperature). The frequency distribution of hatch at each of four constant temperatures was unimodal and approximated a normal distribution. Nymphal development at 22°C required 2.8±0.2, 3.8±0.2, 4.0±0.3, 3.9±0.2, and 6.0±0.3 days for instars 1–5, respectively.

The recognition of four taxa within the calligraphus species group of the genus Ips DeGeer is supported by breeding experiments, karyology, morphology, ecology, and distributions. Ips calligraphus calligraphus (Germar) occurs in the eastern United States and adjacent parts of Canada. Ips c. ponderosae (Swaine) occurs in the range of Pinus ponderosa in the Black Hills, eastern Rocky Mountains, and in the northern Sierra Madre Oriental in Mexico. Ips c. interstitialis (Eichhoff) occurs in the Caribbean Archipelago but the homogeneity of populations on the islands of Hispaniola and Jamaica and the true type locality are uncertain. Ips apache Lanier infests various pines (excluding pinyon pines) at lower altitudes from southeastern Arizona through Mexico. Populations south of the Isthmus of Tehuantepec in Caribbean pines on the east coast of Central America are provisionally considered to be I. apache. Pairings of female I. calligraphus subspecies with male I. apache were infertile. Reciprocal pairing produced rare, sterile hybrids. Fertility of I. calligraphus subspecies was normal when I. c. calligraphus was the female but reduced when the female was either I. c. ponderosae or I. c. interstitialis. All members of the group had 15 pairs of autosomes plus a sex bivalent (2n = 32) that assumed a “parachute” configuration to give a male meiotic formula of 15 AA + Xyp. Second meiosis chromosomes of I. apache lack some of the heterochromatic arms present in I. calligraphus. Meiotic divisions of rare interspecific hybrids (I. apache ♀ × I. calligraphus s. lato ♂) had numerous autosomal rearrangements, a possible translocation, and oversized (probably tetraploid) spermatozoa. Meiosis was mostly normal in intersubspecific hybrids, but the presence of occasional anaphase bridges or nonmigrating chromosomes and alignment of pachytene homologs revealed inversions and other possible rearrangements. Univariate and multivariate analyses of pars stridens strial width, pronotal width, and male genitalia revealed significant differences among all four taxa.

The relationship between temperature and ovarian development rates, as well as the cumulative probability of a female becoming gravid, were determined for the house fly, Musca domestica (L.), based on previously published information. These relationships were combined to form a model that simulates oviposition of house fly populations using average daily temperatures, eggs per cycle, and daily survival as input. Simulation results were compared with observed oviposition in three caged populations of house flies exposed to field temperatures. A high correlation occurred between simulated and observed eggs laid (r = 0.88), as well as between simulated and observed lxmx (r = 0.91). The model overestimated the onset of oviposition for one population, but closely simulated the timing of oviposition for the other two. The model also tended to overestimate the reproductive contribution of flies during the second and subsequent ovarian cycles.

A double application of Disparvirus, a nuclear polyhidrosis virus, at 1.25 × 1012 polyhedral inclusion bodies (PIB) per hectare, giving a total of 2.5 × 1012 PIB per hectare, was applied aerially on three plots in an emitted volume of 10.0 L per hectare. The two applications were 3 days apart and most larvae were in the first instar. Three plots were selected as untreated checks; each was paired with a treated plot on the basis of pre-spray gypsy moth egg-mass numbers and locality. The pre-spray egg-mass counts ranged from 1430 to 8520 per hectare in the six plots. Assessment of the treatment was based on numbers of pupae and fall egg masses as well as on estimates of defoliation and on microscopic examination of larvae collected at weekly intervals to determine the incidence of virus infection. Between 12 and 19 days post-spray, 49, 61, and 85% of the larvae were infected with virus in the three treated plots compared with 3, 7, and 14%, respectively, of larvae in the check plots. Red oak was 14% defoliated in two of the treated plots compared with 82 and 90% in their corresponding check plots. The third plot suffered 46% defoliation due to leaf-eating caterpillars other than gypsy moth; defoliation in its corresponding check plot was 31%. Reductions in egg-mass numbers in the treated plots were 76, 93, and 98% compared with an increase of 56% and decreases of 50 and 70%, respectively, in corresponding check plots. Corrected population reductions (Abbott’s formula) were 84, 85, and 92% in the three treated plots.

Ips mexicanus (Hopkins) and I. paraconfusus Lanier can transmit a frugal pathogen that causes pitch canker [Fusarium subglutinans (Wollenw, and Reink.) Nelson, Toussoun, andMarasas], a disease recently identified in Monterey pines (Pirns radiata D. Don) in California. In Santa Cruz County, F. subglutinans was recovered from Ips spp. that emerged from pitch canker-in fee ted P. radiata and were captured in multiple-funnel traps baited with racemic Ips spp. pheromones. Ips paraconfusus adults experimentally contaminated with propagules of the fungus transmitted it to seedlings and mature pines. Field transmission was demonstrated when cankers were produced following pheromone-induced beetle attacks on pines. Ips spp. inoculated F. subglutinans into pine slash, thus creating reservoirs of this fungus. Larvae, pupae, and young adults acquired the fungus when their parents introduced it into logs. Ips spp. progeny production and development were not significantly altered by the fungus. In proximity to other bark beetle-associated fungi, growth of F. subglutinans was reduced and patchy. A new association may be developing among native Ips spp. and F. subglutinans.

Encapsulation of Bathyplectes curculionis (Thomson) and B. anurus (Thomson) (Hymenoptera: Ichneumonidae) was investigated by dissecting parasitized larvae of three strains of the alfalfa weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae). In laboratory studies, there was no encapsulation of B. curculionis in the western strain of the weevil, a significant level of encapsulation in the eastern strain of the weevil, and nearly complete encapsulation in the Egyptian strain of the weevil. The rickettsia, Wolbachia postica Hsiao and Hsiao, found only in the western strain, was not involved in encapsulation. Variation in encapsulation was due to biological differences between weevil strains. Encapsulation rates among field populations of the western and Egyptian weevils were lower than in the laboratory. Encapsulation rates of weevil populations from zones in which western and Egyptian strains overlap in southern Utah, and between eastern and western strains in Colorado, were intermediate to rates of parental strains. These results imply that B. curculionis effectiveness against the western alfalfa weevil will decline with mixing of weevil strains. Bathyplectes anurus did not evoke encapsulation and was able to develop equally well in all three weevil strains. Our findings illustrate the importance of investigating the compatibility between alfalfa weevil strains and their parasitoids in devising a sound biological control strategy.

Beginning 1 year after an intense forest fire in the Interlace region of Manitoba, carabid beetles were sampled by pitfall trapping in two burned sites and two unburned control sites. Before the tire, one burned site had been dominated by aspen, Populus tremuloides Michx,, and the other by conifers (mostly Picea spp.). During the 11-year study, burned sites became dominated by aspen saplings. Three carabid species were caught significantly more frequently in burned sites than in control sites. Two of these, Harpalus laticeps LeConte and H. egregius Casey, invaded soon after the fire and were caught in the burned sites for several years after the fire. Seventeen species were caught significantly less often in burned than in control sites; catches of another 13 common species were not significantly affected by burning of the site. Burning influenced the seasonal patterns of catches of Carabus taedatus F. and Pterostichus adstrictus Eschscholtz; this was attributed to higher litter and soil temperatures in burned sites. Seasonal patterns of other common species were not markedly affected by burning. In burned sites, the incidence of brachypterous species and the size of beetles increased with time after the fire. In control sites, the incidence of brachyptery was independent of time, but the percentage of brachypterous species was significantly higher in the conifer site than in the aspen site. Trends of brachyptery and size are those expected if early colonizers are super-tramp r-strategists and later invaders are K-strategists. Patterns of species occurrence during forest regeneration can be explained in terms of dispersal and competitive abilities, preference for physical attributes of the habitat, and responses to prey availability.

Coleophora deauratella Lienig and Zeller is reported for the first time in North America. This casebearer species was introduced accidentally from Europe almost 30 years ago but remained unrecognized. It currently is known from eastern Canada and northeastern United States. Larvae feed on seeds of red clover, Trifolium pratense L. Diagnostic characters of the larval case and the adult, as well as features separating C. deauratella from two similar casebearer species, are presented.

Natural nests of the Africanized honey bee near Tapachula, Chiapas, Mexico, were examined during March and April 1988, approximately 18 months after initial colonization. Most were in hollow trees, but open nests and nests in arboreal termite nests occurred. All nests were less than 6 months old and most less than 2 months. The modal cavity volume was 10–20 L. No brood diseases were seen. Colony density was estimated to be about six per square kilometre, higher than the density of man-kept hives.

Larch sawfly oviposition activity as revealed by scarring of long shoots of eastern larch, Larix laricina (DuRoi) K. Koch, was measured at various locations in the high boreal forest and forest tundra in Québec in 1988 and 1989. The data show that larch sawfly is established up to the tree line, even on isolated larch growing under climatic conditions that are extreme for this tree. Frequency distributions of scarred shoots as a function of time suggest thai larch sawfly populations reached outbreak levels in the 1980s, with peak numbers in 1981 for the high boreal, and in 1985 for the subarctic regions sampled. Trends in long shoot production by larch trees started to fluctuate simultaneously with the sudden increase in larch sawfly populations along the Grande Rivière de la Baleine in 1984. In this region in 1985, the proportion of long shoots used by Pristiphora erichsonii averaged 20–35%, which may have limited further population increase. Although foliage reduction and branch mortality were observed, mortality of whole trees was not a general characteristic of this outbreak.

The within-plant spatial distribution of Limothrips denticornis Haliday eggs on spring barley (Hordeum vulgare L.) in North Dakota was examined during the growing seasons of 1987 and 1988. In both years, most eggs were found during inflorescence emergence (growth stages 10–10.5 on the Feekes scale), although eggs were detected both prior to and after these growth stages. Once inflorescence emergence was initiated, over 8.5% of the eggs were found in the top two leaf sheaths, with the majority in the flag leaf sheath. Over all barley growth stages, significantly more eggs (P≤0.05) were found in the middle third than in either the top or bottom third of the flag leaf sheath. No difference (P≥0.05) in the within-sheath location of eggs on lower leaves was detected.

A new genus and species, Sacculozetes filosus, is described from riparian grassland in the Soviet Far East, and a new species, Guatemalozetes danos, is described from shortgrass and alpine prairie in western North America, both on the basis of adults. The genus Guatemalozetes Mahunka is redefined; this is the first record of this genus from temperate North America. A close relationship is indicated between Sacculozetes and Lamellobates Hammer, Paralamellobates Bhaduri and Raychaudhuri, and Hypozetes Balogh. The uncertain family placement of Sacculozetes and Guatemalozetes within the Ceratozetoidea is discussed. Adults of both genera exhibit character states of the Mycobatidae, but until immatures are discovered, they are considered unplaced genera in the superfamily.

The jack pine tip beetle, Conophthorus banksianae McPherson (Coleoptera: Scolytidae), has been distinguished from its sibling species, C. resinosae Hopkins, partly because immature stages were present in the field longer and because it may be bivoltine. A life history study of the tip beetle revealed it is univoitine, overwintering as an adult. The developmental period of C. banksianae from eggs to adults is about the same as that for C. resinosae. As in C. resinosae, adult C. banksianae usually mate in the spring, but some mate the previous fall. Mating occurs on or in the host. Female-biased sex ratios are found consistently throughout the life cycle of C. banksianae and in overwintering adults of C. resinosae. In Ontario, oviposition galleries are initiated in the old shoots until mid-June, thereafter in new shoots. Peak oviposition is completed before new shoots have fully elongated. The very similar life history traits of C. banksianae and C. resinosae suggest the species are closely related, if not the same species as recently proposed.

Z8-tetradecenyl acetate (Z8-14OAc andZ8-tetradecenyl alcohol (Z8-14OH) were identified as sex pheromone components of the eyespotted bud moth, Spilonota ocellana (Denis and Schiffermüller) (Lepidoptera: Olethreutidae). Compounds were identified by gas chrornatographic-eleclroantennographic (GC-EAD) and GC-mass spectroscopic analyses and field tested in apple orchards in the Okanagan Valley, B.C. Although Z8-14OAc alone was attractive to male S. ocellana, the addition of 1–5% Z8-14OH strongly synergized its attraction. Field tests comparing the attractiveness of virgin female S. ocellana with various doses of a 99:1 blend of Z8-14OAc and Z8-14OH indicated the natural sex pheromone has only two significant components. A 99:1 blend of Z8-14OAC and Z8-14OH is suggested for monitoring and control of S. ocellana populations in British Columbia.

Rudolfina digitata sp.nov. (Diptera, Sphaeroceridae, Limosininae) is described from the Yukon and Alaska and from alpine tundra in Alberta, Wyoming, Colorado, New Mexico, and New Hampshire. This distribution is discussed with respect to the hypothesis that these areas are postglacial refugia for arctic and subarctic species.

Twenty species of Tabanidae in three genera [Hybomitra (15 spp.), Tabanus (four spp.), Haematopota (one sp.)] were caught in Manitoba horse fly traps from mid-May to mid-July in 1987, and from mid-May to mid-August in 1988. Hybomitra lurida (Fallen) and H. nitidifrons nuda (McDunnough) peaked in abundance in late May to early June; H. illota (Osten Sacken) and H. lasiophthalma (Macquart) in early June; H. affinis (Kirby), H. arpadi (Szilady), and H. zonalis (Kirby) in mid-June; H. epistates (Osten Sacken) and H. pechumani Teskey and Thomas in late June to early July. Abundance of H. trepida (McDunnough) peaked twice, in late June and early August. Tabanid density and diversity were greatest during June; few flies were present at the site after mid-July. For most species, at the beginning of the flight season, 80–100% of flies dissected were nulliparous. After approximately 1 month of flight activity, parity in all but three species reached levels approaching 100%, and remained high thereafter. Hybomitra lurida and H. nitidifrons nuda were 100% parous within 2 weeks of their first appearance in traps. Parity of H. trepida increased to 100% after 4 weeks, declined to 40% 2 weeks later, and returned to 100% after another 2 weeks.