Fenvalerate resistance was monitored in Psylla pyricola Foerster populations at 51 sites in Washington, Oregon, California, and British Columbia during early 1988. Resistance levels ranged from susceptible in an organic orchard in the Willamette Valley, OR, and at several other sites in Oregon and California, to highly resistant (> 100-fold compared with a susceptible strain) at several sites in central Washington. Generally, resistance levels were greater in the north than the south. In the Wenatchee and Yakima/Ellensburg, WA, areas, pyrethroid resistance was areawide, showing similar levels in both heavily treated and untreated orchards. In the Willamette Valley, OR, pyrethroid resistance was local and more consistent with the treatment histories of individual orchards. Factors influencing regional resistance appeared to be the species pool size of resistant and susceptible pear psylla, the intensity of spraying, and the unique host plant, life cycle, and dispersal attributes of this pest. Reasons for high regional resistance in central Washington and not in southerly areas are unknown, but this pattern is consistent with earlier patterns of insecticide resistance in pear psylla. The observed trends in fenvalerate resistance are discussed in relation to limiting resistance in pear psylla.

Resistant potato plants influenced the parasitoid Edovum puttleri Grissell directly, as well as indirectly through eggs of the parasitoid’s host, the Colorado potato beetle, Leptinotarsa decemlineata (Say). In the field, E. puttleri parasitized more egg masses on plants with no glandular trichomes or with glandular trichomes bearing only enclosed droplets of exudate than on plants with two types of glandular trichomes (one with exposed droplets and the other bearing enclosed droplets). Trichomes with exposed droplets entrapped numerous parasitoids. Although rearing L. decemlineata on resistant plants influenced many of the beetle’s life-history traits, it did not affect the suitability of their eggs for development and survival of preimaginal E. puttleri. However, eggs from L. decemlineata that were reared on resistant potato plants reduced the longevity of the parasitoids and also reduced the number of hosts (eggs) killed by parasitoids.

White fir cones were sampled for insect damage from wild stands in California and Nevada during 1984–1986. Insects were recovered from cones and seed damage was partitioned by insect species. The important phytophagous insects were separated into guilds: the cone- and seed-mining guild, Dioryctria abietivorella Groté, Eucosma prob. siskiyouana (Kearfoot), Cydia prob. bracteatana (Fernald), Barbara sp.; the seed-feeding guild, Megastigmus pinus Parfitt, M. rafni Hoffmeyer, Earomyia abietum McAlpine; and the scale- and bract-feeding guild, Asynapta hopkinsi Felt, Dasineura prob. abiesemia Foote, Resseliella conicola (Foote), Strobilomyia abietis (Huckett). Total damage by insects varied by year and site, reaching a maximum of 47% in 1986 on one site and a minimum of 12.5% in 1984 on another. Abortion and incomplete development also were major factors in the production of sound seed. Populations of white fir cone and seed insects varied with cone crop but also were affected by the occurrence of cone crops on alternate hosts. During most years, the seed-mining guild insects were the major cause of seed damage.

Spatial and temporal variability are essential considerations in the study of aquatic insects. Traditionally, these two sources of variability are treated separately; however, they should be considered together because they occur concurrently in natural systems. To illustrate this interaction, we constructed two-way variability tables in which spatial (habitat, reach or zone, system, intersystem) and temporal (within a day, within a season, within a year, year to year) scales were ordered on separate axes, and examples of concurrent spatial and temporal variability were entered at the intersects of the scales. We examined three aspects of aquatic insect life histories in lotic and lentic waters using such tables: emergence, feeding and growth, and movements and migrations. It proved easier to find examples for the stream tables than for the lake tables, perhaps because of greater spatial and temporal variability in lotic than lentic waters. Also, more papers have been published on stream than on lake insects over the last decade or so. Spatial and temporal scales at which lotic and lentic research is done were determined by examining the recent contents of five key aquatic journals (≈ 500 articles). Research on aquatic insects appears generally to be done at relatively long temporal scales, but at smaller spatial and shorter temporal scales in lotic than lentic systems. Perusal of the literature to find examples of concurrent spatial and temporal variability revealed the prevalence of a “mean-values” appproach to data analysis, in which investigators “homogenize” data to reduce spatial and temporal variability. However, it is this spatial and temporal variability that often provides an explanation of factors causing the patterns observed. A “variance” approach, in which data are disaggregated and fluctuations or extremes are considered, may be far more informative and may elucidate underlying mechanisms.

Recent studies have suggested that the stylostome of parasitic larval water mites of the genus Arrenurus Dugès is a product of the mite, not the host. We tested this hypothesis by comparing stylostomes of the similar species Arrenurus novimarshallae Wilson and Arrenurus pseudotenuicollis Wilson formed in each of two mosquito species, Anopheles crucians Wiedemann and Anopheles quadrimaculatus Say: if the stylostome is produced by the mite, not the host, then stylostome form is likely to be constant in different host species parasitized by the mite.

The stylostome of A. pseudotenuicollis is a short, broad, convoluted sac, and stylostomes within the two host species did not differ significantly. The stylostome of A. novimarshallae is a long, thin, convoluted tube, and although it was significantly smaller in A. quadrimaculatus than in A. crucians, its form remained constant. Dark pigment deposits around the stylostome’s attachment point and along the tube may represent host defense that reduces stylostome growth in A. quadrimaculatus. Laboratory-reared A. novimarshallae often die after a brief engorgement period on A. quadrimaculatus but not on A. crucians.

Thus, the stylostome of these two mite species has a consistent form in each of two host species, an observation compatible with the hypothesis that the stylostome is a product of the mite. In addition, the ease of distinguishing these two mite species on the basis of stylostome morphology attests to the potential value of the stylostome as a taxonomic character.

The larvae of Pterostichus (Bothriopterus) ohionis Csiki and P. (Gastrellarius) blanchardi Horn are described and compared respectively with the other known larvae of Bothriopterus Chaudoir and Gastrellarius Casey. A key to larvae of 38 species of Pterostichini occurring in eastern North America is presented.

Relationships between temperature and immature developmental rates of apterous and alate Rhopalosiphum padi (L.) were determined in laboratory experiments conducted at constant and fluctuating temperatures. Lower and upper thresholds for development were 5.78 and 25.09 °C, respectively. Studies at fluctuating temperatures which simulated average and extreme low and high temperatures occurring during late-spring in eastern South Dakota were conducted to determine developmental rates and age-specific life table statistics. Developmental rates for cohorts exposed to variable temperatures were similar to expected developmental rates determined from constant temperature studies. Age-specific life table statistics differed among alate and apterous R. padi exposed to identical temperature regimes. On a day time scale, population growth rates of either morph increased with increasing temperature. When data were expressed on a degree-day time scale, population growth rates were similar for cohorts of either morph exposed to low and average temperature regimes. Population growth rates declined for cohorts of both morphs exposed to high temperatures. Equations were provided that estimate age-specific survival and natality for fluctuating temperatures. Stable nymphal instar distributions for apterous R. padi were similar at all temperatures; for populations with stable age structures, approximately 55, 15, 10, 7, and 10% of individuals would be first, second, third, and fourth nymphal instars, and adults, respectively.

The braconid parasitoid Meteorus trachynotus Vier. was found in overwintered larvae of the obliquebanded leafroller, Choristoneura rosaceana (Harr.), on foliage of a variety of deciduous species, well before the parasitoid’s attack on the spruce budworm, Choristoneura fumiferana (Clem.). In the spring, percentage parasitism of C. rosaceana by M. trachynotus was 8.0 and 18.8% in 1986 and 1987, respectively. Maximum parasitism on C. fumiferana (35 and 4% in 1986 and 1987, respectively) was reached in late June, at a time when over 50% of M. trachynotus cocoons found on deciduous vegetation had emerged. Twenty days later, parasitoids produced on C. fumiferana reached 50% adult emergence. The catches of adult parasitoids on sticky traps placed on deciduous trees and on conifers showed two periods of adult activity. Based on the sex ratio of captured parasitoids, male M. trachynotus were active at emergence sites, whereas females were found mostly in the habitats of available hosts. The phenology of C. rosaceana was observed in 1987. As indicated by light-trap captures, males fly sooner than females. Eggs were laid in July, and so the early larval stages were available to female M. trachynotus as overwintering hosts. Several parasitoids common to C. rosaceana and C. fumiferana were identified.

Numerical analyses were performed on three nominal species of the family Tristiridae. The synonymy existing between Philippiacris Liebermann and Elasmoderus Saussure is corroborated. Philippiacris rabiosus Liebermann is placed in synonymy under Elasmoderus lutescens (Blanchard) as a morphotype. The new combination Elasmoderus wagenknechti (Liebermann) is proposed, and a new species from Chile, Elasmoderus minutus, is erected.

The life stages of Macroglenes penetrans (Kirby), an egg–larval parasitoid of the wheat midge, Sitodiplosis mosellana (Géhin), are described. The mean length and width, respectively, of 25 parasitoid eggs deposited in host eggs were 0.105 ± 0.008 (SD) mm and 0.041 ± 0.006 mm. Mature oocytes were 0.131 ± 0.008 mm long by 0.038 ± 0.004 mm wide, slightly larger than laid eggs.

A frequency distribution of head width (HW) indicated two larval instars during the feeding period. During development, the HW of the first instar remains almost constant at about 0.03 mm whereas body length (BL) increases from about 0.15 to about 0.3 mm. Both HW and BL increase in the second instar from about 0.15 and 0.49 to 0.34 and 1.05 mm, respectively, for mature larvae. The third instar does not feed and is characterized by hook-like "pseudomandibles" and four incurving spines on the terminal segment. The pupa is adectious exarate. Adults are about 2 mm long, shiny bluish-black, and have translucent wings. Males have prominent rust-coloured eyes; eyes of females are less prominent and fuscous.

The striped pine scale, Toumeyella pini (King), had three generations per year in south Georgia. Females developed on snoots and males developed on needles of loblolly pine, Pinus taeda L. Generations overlapped and crawlers were most abundant in May, mid-July to early August, and late October to early November. The average fecundity was 1865 crawlers per female. Parasitism averaged ca. 15%, but the predation rate reached 50%. Coccophagus lycimnia Walker (Hymenoptera: Aphelinidae) was the most common parasitoid reared from both males and females. A pyralid larva, Laetitia coccidivora (Comstock), was a frequent predator of females.

Adults of Cyclomomonia andrewi gen.nov., sp.nov. are described from interstitial habitats in small, cascading streams in western North America. The genus Cyclomomonia and the subfamily Cyclomomoniinae are proposed and diagnosed, based primarily on the distinctive, complex structure of the dorsal and ventral shields and the genital field. Possible relationships between Cyclomomonia and other Momoniidae are discussed, and a new key to the world genera and subgenera of the family is presented.

From 1976 to 1986, the average date of first male pheromone trap catch of grape berry moth was 20 May with an average degree-day (DD) accumulation (base 10 °C) of 150.1 (SE = 13.2). Fifty percent cumulative trap catch of the first generation of males averaged 334.1 (SE = 7.8) DD with an average date of 11 June. Degree-day accumulation was a more accurate method for predicting peak male trap catch than predictions based upon vine phenology and calendar date. Within-field distribution and levels of berry moth infestation were markedly affected by the surrounding habitat. Wooded edges or hedgerows were closely associated with an increase in the level of damage along vineyard borders and higher levels of overall infestation when compared with vineyards without wooded edges. Egg and larval infestation levels in wild hosts (Vitis spp.) were greater than those within adjacent commercial vineyards. Early in the season, male berry moth were trapped in high numbers in wooded areas adjacent to vineyards. After mid-July, males were trapped predominantly within vineyards and few were trapped in wooded edges. Movement of adults from wooded areas into vineyards is not suggested by observed patterns of female oviposition. Females oviposited primarily on wild hosts within the wooded areas and within the adjoining vineyard edges throughout the season.

Halictus rubicundus (Christ) is a primitively eusocial halictine bee. Studies of electrophoretic variation at 48 loci for 37 enzymes with an average of 38 bees per locus provided an expected heterozygosity of 0.038 ± 0.018 for a population from Vancouver, B.C. This value is well within the range found for other primitively eusocial bees and wasps. Comparisons of allozyme mobilities made among samples from France, Alberta, and Vancouver indicated that there are some genetic differences, with the French sample appearing particularly distinct. The loci Diaph, G3pdh-1, and 6Pgd-1 had variants with both alleles at high frequency within the Vancouver population. These loci could provide good estimates of the average relatedness between nest mates.

Females of Heliothis zea (Boddie) were stimulated to produce pheromone by injection of brain – subesophageal ganglion homogenates. Females injected with this homogenate during the photophase produced the same amount of pheromone and same ratio of components as neck-ligated females injected during the peak of pheromone production. Decapitated females and isolated abdomens also produced pheromone when injected with the brain – subesophageal ganglion homogenate during the photophase. These data show that the neurohormone which stimulates pheromone production is not degraded by enzymes during the photophase and that pheromone is not metabolized at a greater rate during periods when the insect is not producing pheromones.

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.

A gallery system and the mature larva of Dendroctonus punctatus LeConte are described from white spruce in Montana. The gallery is allied to that of the Eurasian D. micans (Kugelann) but the larva differs particularly in having a sclerotized area on the eighth abdominal tergum that is lacking in D. micans. Similar native species are D. murrayanae Hopkins, which infests pines, and D. rufipennis (Kirby), which infests spruces. A key and diagnostic characters are presented for identifying D. punctatus larvae.

Larvae of Rhyncholimnochares kittatinniana Habeeb are described — the first larval description within the subfamily Rhyncholimnocharinae. The larval instar is apparently wholly aquatic, making members of this genus the fourth lineage within the Hydrachnidia to have acquired this lifestyle independently. Various morphological characteristics of larval R. kittatinniana are adaptations associated with crawling through boundary-layer flow within the gravel of stream beds. Larvae and nymphochrysalids were found attached to the abdominal tergites of elmid beetles within the respiratory airspace.

An illustrated key to the genera of Braconinae from America north of Mexico is provided. Lapicida aquatica Quicke gen.nov. and sp.nov. from Ontario and Iowa, and Compsobraconoides robustus Quicke gen.nov. and sp.nov. from Texas, Florida, and Mexico are described and illustrated. Bracon albispina Cameron is transferred to Compsobraconoides and a key is provided to enable its separation from Compsobraconoides rufus Quicke sp.nov. Chartobracon van Achterberg is recorded from the New World for the first time and a new species, C. canadensis Quicke sp.nov. from Canada, is described, illustrated, and distinguished from C. huggerti van Achterberg from Europe. Seliodus Brèthes is synonymized with Bracon Fabricius on the authority of C. van Achterberg. Relationships of the new genera are briefly discussed and notes are provided on all of the Nearctic genera.

Male native elm bark beetles, Hylurgopinus rufipes (Eichhoff), had distinctive simple multipulse stress and rivalry chirps, and a bimodally patterned premating stridulation at the gallery site. Males were strongly arrested at attractive female galleries. Not all female galleries were attractive to males. For a short period after the arrival of the first (resident) male, conspecific males often contested the resident male. Stridulation by females was not detected.