The southern pine beetle, Dendroctonus frontalis Zimmermann, was studied in the laboratory to determine the influence of associated fungi on its reproduction. First-generation (P) surface-sterilized beetles associated with mycangial fungi (Ceratocystis minor [Hedgecock] Hunt var. barrasii Taylor or SJB 122) constructed more galleries and laid more eggs, at faster rates, than P beetles not associated with these mycangial fungi. No significant differences occurred among non-surface-sterilized P beetles associated with the phoretic blue staining fungus Ceratocystis minor (Hedgecock) Hunt and mycangial fungi or among progeny of P beetles (F1 generation) carrying mycangial fungi. P and F1 surface-sterilized beetles produced more eggs at a greater density than non-surface-sterilized beetles associated with blue stain, but gallery length and the rate of construction were not different. P and F1 surface-sterilized beetles laid more eggs and constructed galleries faster than surface-sterilized beetles that carried no mycangial fungi. The re-emergence rate of beetles was fastest for P beetles associated with C. minor and significantly slower for fungus-free P beetles, P beetles carrying only mycangial fungi, and F1 beetles, respectively. The F1 generation emerged fastest when associated with both mycangial fungi and slowest when associated with SJB 122, and C. minor var. barrasii or no fungus, respectively. This study employed a successful new rearing technique for isolating specific southern pine beetle/fungal associations.

A change in the feeding behavior between small and large larvae of gypsy moth, Lymantria dispar (L.), is an important part of the insect’s biology. This paper describes how to build a lighting system with incandescent and fluorescent light in the laboratory to induce a change in feeding behavior similar to the change that occurs in the field. The change in feeding behavior was observed on artificial “tree stems” constructed from 5-cm ABS plastic pipe and fitted with felt and cardboard “bark flaps”. On the day before pupation began, 85% of the population migrated down the artificial tree stems to seek shelter under the bark flaps; only fourth-, fifth-, and sixth-instar larvae were observed exhibiting this behavior.

Controlled field studies carried out in plots within a field of NorMan flax, Linum usitatissum L., showed that the loss of flax plants caused by the red-backed cutworm was proportional to the number of cutworm larvae present. A density of 16 larvae per 0.5 m2 destroyed most plants by severing the plant stems at the soil surface. The loss of only some plants at larval densities lower than 16 larvae per 0.5 m2 resulted in a small but significant increase in per plant yield but the increase did not completely compensate for the yield reductions caused by plant loss. The larvae removed plants in blocks with the result that the density of the remaining plants was unchanged and the opportunity for compensating plant growth was limited. An equation defining this relationship between larval densities and yield is presented. Ancillary experiments in which the population of cutworm larvae was sequentially sampled showed that, after an initial loss of about 20% when the plots were established in the field, the larval population remained constant. The proportion of the larvae found around damaged plants also remained constant until the larvae became immobile through preparation for pupation. Because of this stable relationship, reliable estimates of potential crop loss from cutworm larvae in flax should be possible by sampling for cutworms only around damaged plants within a specified row length.

A temperature-dependent multiple cohort simulation model was used to predict emergence of western corn rootworms, Diabrotica virgifera virgifera LeConte, from the soil. Hourly 10-cm-depth soil temperatures were used as input to the model. Hourly soil temperatures were predicted from daily minimum and maximum 10-cm-depth soil temperatures using a half-sine-wave approximation, or from minimum and maximum daily 1-m-height air temperatures using a model for predicting soil temperature from air temperature. The mean difference in the number of days between predicted and observed 50% emergence was 0.22 days using soil temperatures and 0.00 days using air temperatures. Linear regressions of predicted versus observed Julian dates of 10, 50, and 90% cumulative beetle emergence from the soil indicated that model predictions were reasonably accurate and precise using both soil and air temperatures.

The species of Macroneura Walker are revised for America north of Mexico. Seven species are recognized, of which M. camptoptera, M. cerasma, M. chrysosinamora, and M. tanyaris are described as new; M. meteori (Gahan) is removed from synonymy with M. epicaste (Walker) and accorded specific status. Eupelmus melanderi Brues is synonymized with Eupelmus dryorhizoxeni Ashmead and the taxa are reassigned to Eupelmus Dalman from Macroneura. Diagnostic features are given to distinguish females and males of Macroneura from members of other eupelmine genera; putative phylogenetic relationships of Macroneura are discussed, and a key is presented to distinguish females and known males of the North American species.

Annual spruce budworm, Choristoneura fumiferana (Clemens), survey data were subjected to multiple and logistic regression analyses to examine the relationship between egg mass density in the fall and resultant defoliation the next season. Egg mass density was the most important variable associated with resultant defoliation, followed by current defoliation, regional population trends, host species, and sprays. Together, these accounted for 60% of the variation in resultant defoliation. Balsam fir [Abies balsamea (L.) Miller] suffered greater levels of defoliation than white spruce [Picea glauca (Moench) Voss] at a given egg mass density. Resultant defoliation of balsam fir also showed a steeper response to egg mass density than resultant defoliation of white spruce. Levels of current defoliation increased susceptibility to defoliation in a similar manner between species, as did regional population trends. Sprays were more effective at reducing resultant defoliation on balsam fir than on white spruce but, overall, did not confer a high level of foliage protection. Predictions of resultant defoliation using the multiple regression models had confidence limits averaging 75%, which are too large to be useful for predictive purposes. The logistic regression equations could be used to predict the probability of a stand receiving light or severe defoliation.

This study examined the dose-dependent effects of synthetic honey bee queen mandibular pheromone on the inhibition of worker ovary development. The range of doses examined was from 10−3 to 10 queen equivalents (Qeq) per day for 43 days; 1 Qeq was the amount of pheromone in an average pair of queen mandibular glands. Ovary class and ovariole number scores were used as estimates of worker ovary development. Queen mandibular pheromone did not inhibit ovary development in workers at any dose.

No correlation was found between the size of male spruce budworm (Choristoneura fumiferana [Clem.]) moths and the duration of their flight in a sustained-flight wind tunnel. The numbers of male moths caught in traps baited with virgin female spruce budworm moths increased as the size of the females increased, but the relationship was significant in only one of eight experiments. Infection with the microsporidium Nosema fumiferanae (Thomson) resulted in smaller insects, but there were no significant relationships between the incidence of infection and male flight duration or female attractiveness.

The fifth-instar larva of Cochylis arthuri Dang is described and illustrated. Characters for separating it from the fifth-instar larva and pupa of Cochylis hospes Walsingham are given.

Five species of Limnoporus Stål (L. canaliculatus [Say], L. dissortis [Drake and Harris], L. nearcticus [Kelton], L. notabilis [Drake and Hottes], and L. rufoscutellatus [Latreille]) were each sampled at 20 electrophoretic loci. Twofold differences among species in mean heterozygosity appear to be unrelated to presence of wing dimorphism. Low heterozygosity in some populations within species may reflect geographic isolation. There were substantial differences in allele frequency among, but not within, species. Limnoporus rufoscutellatus from western Europe and L. nearcticus from Alaska were the most similar pair of species, with a Nei’s standard genetic identity that is generally found only between populations of the same species. Limnoporus canaliculatus was the most divergent species, and the relationship among L. dissortis, L. notabilis, and the L. rufoscutellatus – L. nearcticus pair is resolved as a trichotomy.

Results of a field experiment indicate that adults of the pine weevil Hylobius pales (Herbst) respond to pheromones of bark beetles. Each sex of H. pales was more attracted to traps baited with the combination of a pine bolt infested with male Ips calligraphus Germar plus the synthetic Dendroctonus Erichson pheromones frontalin and exo-brevicomin, than to traps baited with pine bolts alone. The combined numbers of male and female H. pales caught in traps baited only with Ips calligraphus-infested bolts were significantly greater than numbers caught in traps baited with uninfested control bolts. The attraction of H. pales to bark beetle pheromones may represent a kairomonal response in which weevils exploit semiochemicals from other species that signify a suitable host resource.

The behavioral responses of male spruce budworm moths to a wide range of loadings of synthetic sex pheromone on filter paper and rubber septa were investigated in a wind tunnel. The highest proportion of males flying upwind and reaching filter-paper dispensers occurred at pheromone loadings of between 0.1 and 10 μg. Above these loadings, males were activated but upwind flight was arrested before the moths reached the pheromone source. No such arrestment occurred with rubber septa up to the maximum loading assayed, 1 mg. Up to 72% of the males that reached a septum attempted to copulate with it, but even this response was less than that to a septum in the presence of pheromone emitted by females. This confirms previous conclusions that the synthetic pheromone blend used here, 95:5 (E:Z-11-tetradecenal) is incomplete.

A mark–recapture study examined Trypodendron lineatum (Olivier) spring flight dispersal in a coastal forested valley in British Columbia. Pheromone-baited traps were placed throughout the valley in five separate experiments. Recapture patterns of marked beetles were related to weather, topography, vegetative cover, and source of attractants.

Wind direction within the forest setting, 350 m from the closest open site, was quite variable with a beetle recapture pattern mat was non-directional. At a forest setting less than 50 m from an open site and road, diurnal up-valley winds resulted in an upwind beetle recapture pattern at 25 m from the release site. Beetles were recaptured at distances as far as 1.9 km downwind and 1 km upwind from the release site. Most beetles were recaptured within 2 h of release at distances up to 50 m. In traps at distances of 350–700 m, similar numbers of beetles were recaptured on the day of release as were recaptured during the following week. At distances greater than 1 km, almost all beetles took longer than 1 day to be recaptured.

The oribatid mite genus Megeremaeus is redefined, with the addition of information on leg chaetotaxy and immature instars. Three new species are described, Megeremaeus hylaius from northeastern North America, and M. keewatin and M. kootenai from northwestern North America. Descriptions of the former two species are based on adults and immatures, the latter species on adults only. Nymphs of M. montanus Higgins and Woolley are described. A key is given for the six known species in the genus.

The susceptibility of first-instar cabbage maggot, Delia radicum (L.), to parasitism by seven strains or species of entomogenous nematodes was compared in Petri dishes lined with moist filter paper. The effective doses for 50% mortality (ED50) of the Mexican, Breton, and All strains of Steinernema feltiae Filipjev, of S. bibionis (Bovien), and of Heterorhabditis heliothidis (Khan, Brooks, and Hirschmann) ranged from 98 to 341 infective juveniles per host larva with overlapping 95% confidence intervals; the slopes ranged from 1.36 to 1.07. The DD136 strain of S. feltiae and the species H. bacteriophora Poinar were significantly less lethal with ED50 values of 1113 and 1719 nematodes per host larva, respectively. The addition of a thin disc of rutabaga into the test dishes increased ED50 values by a factor of 20 or more. Application of the Mexican strain of S. feltiae at 5 × 105 nematodes per plant to small caged field plots of rutabaga artificially infested with eggs of D radicum provided control similar to that with diazinon applied at 1.4 L AI per hectare. Practical control of D. radicum on rutabaga with entomogenous nematodes would require strains or species considerably more lethal than those tested here.

Qualitative and quantitative changes in the neutral lipid content of hemolymph of gypsy moths, Lymantria dispar L., were assayed in larval, pupal, and adult stages. The major neutral lipid constituents of the hemolymph were 1,2-diacylglycerols and ranged in nominal concentration from 1.6–3.4 (larval), 3.1–4.9(pupal),toamaximumof 19.3 μg lipid per microlitre hemolymph in the adult male. When detected, triacylglycerols and monoacylglycerols never exceed diacylglycerol concentrations. The fatty acid composition of 1,2-diacylglycerols from adult male moths (0–12 h after emergence) was determined as fatty acid methyl esters using gas chromatography/mass spectrometry analysis. Nine fatty acid structures have been assigned. Of these, five are saturated, unbranched, aliphatic fatty acids (C14:0 – C18:0) which comprise 80.5% of the total fatty acid abundance. The remaining four fatty acids consist of two saturated, methyl-branched, aliphatic compounds, a mono-unsaturated aliphatic acid, and a tri-unsaturated, tricyclic, diterpenoid acid.

Adult Hoplocampa montanicola Rohwer emerged in mid-May, 6.2 ± 3.2 days (mean ± SE) prior to the period of peak anthesis in Amelanchier alnifolia Nuttall. Oviposition, one egg per flower, occurred during the period of petal drop in late-May; a mean ± SE of 2.2 ± 0.2 eggs were deposited in each inflorescence. Eggs hatched 7.7 ± 3 days (mean ± SE) after the period of primary petal drop and larvae fed on a mean ± SE of 1.8 ± 0.14 fruit per infructescence. Larvae completed development by the end of June, just as the first fruit of A. alnifolia were beginning to ripen. Larvae overwintered in the leaf litter.

Adult Anthonomus quadrigibbus Say (previously assigned to the genus Tachypterellus) were first collected in mid- to late-May during the periods of anthesis and fruit drop in A. alnifolia. Immature fruit fed upon were often extensively damaged. Oviposition occurred toward the end of fruit drop in A. alnifolia, 30.6 ± 2.5 days (mean ± SE) after the period of peak anthesis. Only one egg was laid in a puncture at the base of a fruit. Larval feeding was restricted to ovules and occurred in fruit retained on the plant. Pupation and adult emergence occurred in mid-July as fruit were ripening. The new generation of adults then entered the leaf litter to overwinter.

A wide range in feeding damage as defined by leaf scars among 27 cultivars of florist’s chrysanthemum was apparent for the western flower thrips, Frankliniella occidentalis (Pergande). Assessments based on numbers of feeding scars or ranking of cultivars on the basis of the leaf area damaged by feeding were in close agreement. Cultivars with the most feeding damage under growth room conditions, such as cvs. White Marble and Polaris, were the same as those in plots within a naturally infested commercial greenhouse. Under growth room conditions, a 2- to 4-week exposure of plants to a population of thrips was sufficient to evaluate feeding damage. Closely related cultivars had similar levels of feeding damage, and foliage of yellow-flowered cultivars was significantly more attractive to thrips for feeding than foliage of white-flowered sister cultivars during the pre-bloom period. There was a low correlation between feeding damage and incidence of the tomato spotted wilt virus among cultivars in both growth room and greenhouse tests, indicating that virus susceptibility of cultivars was epidemiologically more significant than the feeding activity of western flower thrips.

Reproductive and survival patterns of the heteropteran predator Podisus maculiventris (Say) (Heteroptera: Pentatomidae) were measured under low prey inputs. A single prey, mealworm larva (Tenebrio molitor L.), of one of two sizes (120 or 30 mg), was given to predators for a 24-h period every 1, 2, 4, 8, or 16 days. Additional treatments included: predators provided prey in excess of attack rates; predators given no food; and predators given green bean slices only. Results showed that predators provided with prey survived regardless of feeding interval. When given large prey, predators showed reproductive patterns that were not clearly reflective of feeding interval; only predators fed at 8- and 16-day intervals showed reduced fecundity. When given small prey, the reproductive patterns of predators clearly reflected the feeding intervals. Predators that were fed less frequently laid fewer eggs, less often, and later in life.

Adult corn rootworm beetles, Diabrotica virgifera virgifera LeConte, were maintained at five fluctuating temperature regimens with daily average temperatures of 16.0, 19.5, 23.0, 26.5, and 30.0°C. The mean number of eggs laid per female was greatest (602) at 26.5°C and least (295) at 16.0°C. The median length of life decreased with increasing temperature from 13.8 weeks at 19.5°C to 7.9 weeks at 30.0°C. Parameters were estimated for nonlinear functions relating age-specific fecundity and age-specific survival to physiological age.