Sex-attractant traps were used to monitor the relative abundances of eight species of cutworm and army worm moths at 81 locations in a 13 000-km2 (5000-mi2) area of southern Alberta from 1978 to 1983. Clover cutworm (Discestra trifolii (Hufn.)), variegated cutworm (Peridroma saucia (Hbn.)), bertha armyworm (Mamestra configurata Wlk.), and Leucania commoides Gn. were monitored during spring and early summer, and redbacked cutworm (Euxoa ochrogaster (Gn.)), darksided cutworm (Euxoa messoria (Harr.)), pale western cutworm (Agrotis orthogonia Morr.), and army cutworm (Euxoa auxiliaris (Grt.)) during late summer and fall.

The ranking of moth catches among locations within years was highly consistent, indicating that the spatial pattern of abundance within the survey area remained stable during each flight period. The corollary is that differences in population levels among locations were being consistently detected. Most of the species also exhibited a considerable degree of consistency of pattern of abundance between consecutive years and to some extent over all years.

Estimates of the variability associated with individual traps, between duplicate traps, and among locations were obtained for each species. The within-location variability was always much less than the among-location variability, indicating that a meaningful measure of the relative population level at each location was being obtained. When abundance levels approached economic thresholds the likelihood of moth catches in duplicate traps being within 20% of the mean catch for a location was usually greater than 80%. Year-to-year differences in mean trap catches were frequently significant at the 95% confidence level and the monitoring system could detect relatively small changes in population level between years. Season cumulative trap catches are a composite measure of abundance and the mate-searching activity of males. Weather conditions that restrict male activity are also likely to reduce oviposition by females. Cumulative trap catches may therefore be closely correlated with realized fecundity.

Collection of Podocinum pacificum Berlese from southeastern Ontario represents the first record of the mite family Podocinidae in Canada. Other distribution records including the northerly extent of this species in North America are discussed.

The spatial and statistical distribution of Zeiraphera canadensis Mut. and Free. (spruce budmoth) within the crown of white spruce (< 4 m high) was investigated in northern New Brunswick. A 15-cm branch segment, measured distally from the scales of the branch’s apical growth and taken from the upper one-third of the crown, is considered an adequate sample unit for density estimates of spruce budmoth eggs and larvae. Sample sizes required to estimate spruce budmoth larval densities with given levels of precision and confidence were determined. A sequential sampling plan to classify spruce budmoth populations as low or high (potentially leading to growth reduction and deformed leaders in white spruce) was also developed.

Most emerging 2nd-instar larvae of spruce budworm, Choristoneura fumiferana (Clem.), tested in the laboratory were photopositive and there was no difference in response between healthy larvae and larvae parasitized by Apanteles fumiferanae Vier. However, in the field, parasitized individuals were under-represented among larvae dispersing on silk threads between tree crowns. There is evidence that this was due to the relatively late emergence of parasitized larvae. These parasitized larvae therefore encountered fewer crawling larvae at the tips of branches, and consequently their propensity for dispersing was reduced.

The vertical distribution of dispersing, parasitized larvae caught on sticky traps more closely resembled that of established larvae than it did the vertical distribution of the overwintering population. This indicates that there was some differential redistribution of parasitized and nonparasitized individuals. Despite these differences, the estimate of parasitism by A. fumiferanae based on mid-crown branch samples is justified because it is most consistent and most closely reflects the overall frequency of parasitism.

Descriptions are given of adults of three Limoniidae (Tipuloidea) found preserved in Canadian amber (Upper Cretaceous): Trichoneura (Trichoneura) canadensis sp. nov.; Macalpina incomparabilis gen. nov., sp. nov.; and Limonia albertensis sp. nov.

Using regression analysis on data compiled from the literature, I compared relationships (forewing versus body length) of mayfly imagoes, as a measure of dispersal, between suborders (Schistonota and Pannota) and among habitat type (lotic, lentic, and mixed). There were no significant differences in slopes or intercepts of the regression lines between sexes. Forewing length changed less markedly with body size for species within the ancestral Schistonota than the Pannota. Regression lines for lake and river forms intersect at 7.85 mm (wing length) and 7.30 mm (body length). Small (body length < 7.3 mm) lentic mayflies have proportionately longer wings than small riverine forms. Large (body length > 7.3 mm) riverine mayflies have proportionately longer wings than lentic forms. Based on these relationships, small lake-dwelling mayflies and large riverine mayflies are best able to disperse. Mayfly species occurring in mixed (both rivers and lakes) habitats exhibited allometric relationships similar to mayflies restricted to rivers.

Grasshopper assemblages inhabiting eight pastures of shortgrass prairie rangeland in northeast Colorado were studied for 4–6 years during a general increase and decrease in grasshopper abundance. Average densities increased 10-fold during a 3- to 4-year increase phase, with individual species and populations in separate pastures exhibiting greater or lesser changes. Asynchrony in grasshopper population characteristics was noted. The co-dominant species, Opeia obscura (Thomas) and Melanoplus gladstoni Scudder, exhibited similar trends in density, but M. gladstoni dominance, expressed as its proportion of the population, declined steadily relative to O. obscura. Subdominant species similarly were asynchronous. Species richness did not change during this cycle. Grasshopper densities and assemblage structure were not affected by rangeland management practices of fertilizer (nitrogen) and herbicide (atrazine) application.

The survival and persistence of Nosema locustae Canning in field soils and resident grasshopper populations in Saskatchewan were assessed in a 3-year study. Low levels of N. locustae spores persist in soils but not on vegetation from treated fields. Large numbers of spores were sometimes detected in soil depending on the extent of infection in the resident grasshopper populations. Indigenous soil microorganisms appear to prey upon N. locustae spores or utilize nutrients during spore decomposition. Nosema locustae infection in resident grasshoppers varied, depending on the viability of the spores applied, and its level was higher following repeated (3-year) applications. Low numbers of N. locustae spores persist in soil but large populations probably will not accumulate because of leaching and because of their interaction with soil microorganisms. Spores appeared to leach through soil as a function of water movement.

Parasitism by Scelio calopteni Riley in eggs of Melanoplus bivittatus (Say) and M. sanguinipes (Fabr.) in Saskatchewan during 1967–1980 was highly aggregated. There was no evidence of any numerical response of the parasites to adult grasshopper density and, furthermore, change in grasshopper population density was independent of percentage parasitism. Thus, it is concluded that parasitism by S. calopteni does not play a significant role in the population dynamics of the two grasshopper species. The relationship between parasitism and wetness in August was highly significant in both grasshopper species and showed that percentage parasitism increased, but at a decreasing rate, up to a certain wetness and levelled off thereafter.

A study was conducted to examine the springtime hatching characteristics of Melanoplus sanguinipes (F.) and Aulocara elliotti (Thomas) eggs on rangeland. Laboratory experiments showed that eggs of M. sanguinipes required fewer accumulated degree days (DD) to complete post-diapause development than those of A. elliotti at a constant temperature of 23.3°C. Springtime field observations revealed that A. elliotti nymphs emerged prior to or concurrent with M. sanguinipes. Additionally, results suggest that A. elliotti nymphs emerge over a shorter interval than M. sanguinipes. Much of the variation in springtime emergence could be attributed to species-specific oviposition sites, pod depth, and pod orientation that resulted in A. elliotti eggs accumulating heat more rapidly than M. sanguinipes eggs. Results help explain some of the variation found in egg hatching of these two grasshopper species on rangeland.

Collections of Baetis Leach, Baetodes Needham and Murphy, and Dactylobaetis Traver and Edmunds from the southwestern United States and northern Mexico included new species and new distribution records. The nymphal stages of Baetis sonora n.sp. and Dactylobaetis sinaloa n.sp. are described and figured. Species of Baetis nymphs that were given informal epithets, even though they were described, keyed, and their taxonomic characters figured, are named, or tentatively associated with a described adult. Baetis sp. “A” Morihara and McCafferty is tentatively associated as the nymphal stage of B. adonis Traver, Baetis sp. “B” Morihara and McCafferty is named B. libos, and Baetis sp. “C” Morihara and McCafferty is named B. notos. New collection records extend the known distributional limits of Baetis insignificans McDunnough, Baetodes edmundsi Koss, B. fuscipes Cohen and Allen, and Dactylobaetis mexicanus Traver and Edmunds.

An extensive collection of adult Capnia licina Jewett was made in the Mount Baker area, Washington, USA, and from this the previously unknown female is described and illustrated, and the male redescribed and reillustrated.

The genus Praon is revised. Thirteen North American species north of Mexico are recognized, including one new to science: P. carinum sp. nov. Praon cerasaphis (Fitch) and P. coloradense Ashmead are retained as Species inquirende. The female of P. alaskense Ashmead and the male of P. artemisaphis Smith are described for the first time. Praon nanus Baker, P. exsoletum palitans Muesebeck, P. aguti Smith, and P. negundinus Smith are placed in synonymy. The genus Parapraon Stary is considered a synonym of Praon Haliday. A generic diagnosis of Praon Haliday is given, and a key, diagnoses, and illustrations of North American species are provided.

Subspeciation in the circumpolar Nephrotoma lundbecki is discussed for a population from south of the Laurentide Ice Sheet, described here as N.l. alexanderi. For 18 nearctic Nephrotoma species new distribution records are presented, mainly from the northern Nearctic, adding considerably to our knowledge of the distribution of these species. Included is the second nearctic record of the palaearctic species Nephrotoma cornicina (L.).

During 1982 and 1984, ground releases of Trichogramma minutum Riley were assessed for control of the spruce budworm, Choristoneura fumiferana (Clemens), on 12- to 20-year-old, white spruce stands in northern Ontario. Maximum parasitism of susceptible egg masses was 16 and 87% following the release of 480 000 and 12 million female T. minutum per hectare, respectively. Releases at intervals of 1 week maintained parasitism of susceptible egg masses at constant levels throughout the oviposition period of spruce budworm. When parasitism of susceptible egg masses was maintained above 78.2% during the ovipositional period, total egg mass parasitism averaged 58.0% and resulted in an 80.3% reduction of overwintering 2nd-instar larvae. The optimal strategy for reducing spruce budworm was two releases of T. minutum at an interval of 1 week in the ovipositional period. This allowed a second generation of parasitoids to emerge from the spruce budworm eggs that were more efficient in maintaining high levels of parasitism than those emerging from the standard rearing host. Natural parasitism of spruce budworm egg masses was less than 4% and there was no carryover of parasitism in the years following inundative release. The rate of T. minutum release necessary to achieve effective mortality of spruce budworm during outbreak populations is discussed briefly.

Insects were sampled in a Douglas-fir forest in California to evaluate differences among inexpensive survey methods. Sampling was done with sweep nets and with window, sticky, light, suspended cone, and two kinds of yellow pan traps. Also examined were effects of trap location in the given tree and the following tree species: Douglas-fir (Pseudotsuga menziesii Franco), canyon live oak (Quercus chrysolepis Liebm.), tanoak (Lithocarpus densiflorus Rehd.), Pacific madrone (Arbutus menziesii Pursh.), and big-leaf maple (Acer macrophyllum Pursh.). Relative abundance and faunistic similarity of the 9662 insects caught varied greatly by trap type and little by tree species or trap location. Family-level taxonomic richness differed among the diverse trap types, tree species, and trap locations.

Inheritance of gregarious or solitary oviposition in Muscidifurax raptorellus Kogan and Legner involves two phases: (1) the female parasitoid expresses either trait shortly after mating, the magnitude of which is apparently determined by the male genome; and (2) the trait is then apparently fixed into a genome of her offspring who demonstrate it in the virgin state. In the first phase, less than one-half the magnitude of behavioral expression is shown, full expression occurring in the F1 diploid virgin hybrid. In matings with hybrids produced from subsequent backcrosses, more than one-half of the behavior is expressed shortly after mating. Traits related to gregarious oviposition (number parasitoids developed per host and total progeny) were also similarly initially expressed and subsequently inherited. A polygenic mode of inheritance is apparent, with ≥3-22 genes estimated. The extranuclear influences prior to inheritance may involve microorganisms and/or chemicals (enzymes) present in hymenopteran seminal fluid. Natural selection in this system should be accelerated by males causing the expression of a portion of the quantity of heritable behavior within the same generation.

Rhagionids were studied principally by capturing adults in emergence traps at Southington (1979) and in Malaise traps at Hamden (1980–1983) and Guilford, CT (1983–1985). Most captures of Chrysopilus rotundipennis Loew, C. thoracicus (Fabr.), Rhagio mystaceus (Say), and Symphoromyia hirta Johnson occurred during a 2- to 5-week period. Mean capture dates for sexes differed significantly in only a few cases. Based on percentage of total captured, S. hirta and R. mystaceus ranked first and second at Hamden whereas C. rotundipennis and S. hirta had these respective ranks at Guilford. The sex ratio of C. ornatus (Say) adults in emergence traps did not depart significantly from 1.0, but most rhagionids captured in Malaise traps had skewed sex ratios. Based on percentage and quotient of similarity, faunas at Hamden and Guilford shared many species, but relative abundances of species common at one or both sites were very different. In this study, we found 14 rhagionid species, including 4 not previously recorded from Connecticut. A total of 16 species are now recorded from the state.

Thelytokous reproduction was developed and fixed in arrhenotokous Muscidifurax raptor Girault and Sanders by mating hybrid females, of interhemispheric strains, with naturally occurring males of M. uniraptor Kogan and Legner. A change in ovipositional behavior was shown by these mated hybrid females which subsequently produced thelytokous Fx offspring for 10 generations. Sperm depletion and extranuclear factors are considered.

Three sequential-sampling plans were developed for adult Diabrotica barberi Smith and Lawrence and D. virgifera virgifera LeConte in field corn in southern Ontario. The distribution of both species was well approximated by the negative binomial distribution and obeyed Taylor’s power law. Two plans, following the methods of Kuno (1969) and Green (1970), estimated populations with predetermined precision. The third plan, based on Wald’s (1947) sequential probability ratio test, categorized populations relative to an economic threshold. Different sequential-sampling plans were constructed for 1st-year fields and for all other fields because the parameter k, measuring the extent of aggregation of the beetles, differed between these two classes of fields. Decision equations for Wald’s plan in 1st-year fields were: D1 = 0.98n − 17.75 and D2 = 0.98n + 13.82. Decision equations for 2nd-year or older fields were: D1 = 0.99n − 13.42 and D2 = 0.99n + 10.45. The use of Wald’s plan reduced the required sample size by 55% in 1st-year fields, and by 48% in all other fields. The savings associated with the other sequential-sampling plans were not significant.