Additions of feeding stimulants have been reported to increase the efficacy of Bacillus thuringiensis based insecticides (Bartelt et al. 1990). pheast™ (Miller Chemical and Fertilizer Corp., Hanover, Pennsylvania), which derives its trade name from yeast constituents, is one of the most effective feeding stimulants (Farrar and Ridgway 1994). Li and Fitzpatrick (1997) found that the addition of 5% Pheast to B. thuringiensis based insecticides increased the mortality of Choristoneura rosaceana (Harris) larvae fed leaves of raspberry plants, Rubus idaeus L. (Rosaceae), treated with these insecticides in the laboratory. We report results from a test of the effectiveness of Pheast when exposed to field conditions and fed to larvae in the laboratory.

The life history of pine false webworm, Acantholyda erythrocephala (L.), in three pine (Pinaceae) plantations in northern New York is similar to that reported for this species on red pine, Pinus resinosa Aiton, in Ontario. Adult emergence extended from early May to early June. The sex ratio of emerging adults favored males by as much as 2.7:1. Oviposition occurred from mid-May to early June. Significantly more eggs per fascicle were deposited on the distal third of branches and in the lower third of the crown. Larval feeding took place throughout June. The proportion of prepupae remaining in the soil for more than 1 year varied from 9% to 66% between two sites. There was no evidence of egg parasitism, and egg survival exceeded 95% in each of 2 years. A new species of nematode (Steinernema sp.) (Nematoda: Steinernematidae) was recovered from pronymphs. Homaspis interruptus (Provancher) (Hymenoptera: Ichneumonidae) parasitized larvae and emerged from 8.5% and 2.8% of the pronymphs in two populations.

Collembola of 12 sugar maple forests of southern Quebec were surveyed through pit-light trapping and soil core extraction. These two sampling techniques were highly complementary, as pit-light traps are more efficient for sampling epigaeic species while soil core extractions are more efficient for hypogaeic species. A total of 108 species representing 38 genera and seven families was collected. Nine genera and 67 species are new records for the province of Quebec and 12 species are new records for Canada. The distribution of species among the different sites is summarized and taxonomic remarks are provided for 20 problematic species. A low percentage of the Quebec collembolan fauna is shared with Ontario and Newfoundland, which probably reflects an incomplete inventory of the fauna rather than highly different regional patterns in collembolan communities. The use of these two complementary sampling techniques is suggested to improve the inventory of Collembola in future research.

The rhizotrogine genus Malaisius Arrow is revised with descriptions of two new species, M. siamensis from northern montane areas of Thailand, and M. similis from northeast Yunnan, China. The type species, M. mollis Arrow, is redescribed, and Malaisius yunnanus (Moser) (Cyphochilus) is proposed as a new combination. The female of Malaisius is described for the first time and a key to the male species of Malaisius is provided. A discussion of relationships and distinguishing characters of the closely related genera Cyphochilus Waterhouse, Dedalopterus Sabatinelli and Pontuale, and Malaisius is also given.

In 1995, Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae), a commercially available pupal parasitoid of the house fly, Musca domestica L., and stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), was purchased to examine the status of wasps being sold to Manitoba producers. Percentage of pupae parasitized, numbers of parasitoids per pupa, total parasitoids, and parasitoid sex ratio were determined for each shipment of parasitoids received. To determine the extent to which these wasps could successfully parasitize house flies and stable flies, parasitoids were released weekly in four Manitoba dairy barns and levels of parasitism estimated. In 10 622 freeze-killed sentinel house fly pupae, 2.2% were parasitized throughout the season by N. vitripennis, and 5.8% were parasitized by eight other species of parasitoids. Of 11 897 naturally occurring house fly and stable fly pupae, 0.6% were parasitized by N. vitripennis, and 3.4% by eight other species of parasitoids. In four barns where there were no releases of N. vitripennis, 1.1% of 11 779 sentinel pupae were parasitized by four species of parasitoids and 3.8% of 8384 naturally occurring house fly and stable fly pupae were parasitized by nine species. The release of an estimated 3 648 093 N. vitripennis did not result in substantial parasitism in either sentinel pupae or naturally occurring pupae. In 1996, live sentinel house fly pupae (n = 50 842) and house fly and stable fly pupae occurring naturally (n = 4691) were collected in two of the nonrelease barns from the 1995 study to examine the activity of endemic parasitoids. Of the sentinel and naturally occurring pupae sampled, 4.0% and 9.4% were parasitized, respectively. Phygadeuon fumator Gravenhörst (Hymenoptera: Ichneumonidae) was the most abundant parasitoid, accounting for 97.4% and 79.9% of parasitoids collected from sentinel pupae and naturally occurring pupae, respectively. Other parasitoids included Urolepis rufipes (Ashmead), Muscidifurax raptor Girault and Sanders, Muscidifurax zaraptor Kogan and Legner, Spalangia subpunctata Först, Spalangia cameroni Perkins, Spalangia nigra Latreille, and a species of Trichomalopsis Crawford (Hymenoptera: Pteromalidae).

Recent damage to sugar maple, Acer saccharurn Marsh., by pear thnps, Taeniothrips inconsequens, in the northeast of the United States and adjacent parts of Canada has led to much research on this pest (Teulon et al. 1993; Teulon and Cameron 1996; Parker and Skinner 1997). A detailed description of the univoltine pear thrips' life history is reported in Teulon et al. (1998). Although T: inconsequens is the dominant species in sugar maple, other thrips may also be important as herbivores, detritivores, or predators and need to be taken into account in sampling or monitoring programmes. This article describes the diversity of thrips in a sugar maple plantation in central Pennsylvania, United States.

This paper describes two related species of the subgenus Paragus (Paragus) Latreille 1804 from two remote regions. The study of material from the Bohart Museum (Davis, California, United States) resulted in the discovery of an undescribed Nearctic species, P. vockerothi sp.nov. Simultaneously, one similar new European species, P. glumaci sp.nov., is reported among material collected from the Balkan Peninsula. The description of both species, with figures of male genitalia and diagnostic characters, is given. The zoogeographical significance of the discovery of these species is emphasized.

The influence of defoliation type (artificial versus natural), timing (early versus late), and intensity (25%, 50%, and 75% of needle mass removed) on leader growth of Scots pine, Pinus sylvestris (Linnaeus), was assessed for 2 years after treatment on an even-aged stand located in southeastern Finland. Trees were defoliated simultaneously, either artificially with a pair of scissors or naturally with larvae of Neodiprion sertifer (Geoffroy) and Diprion pini (Linnaeus) for the early- and late-season treatments, respectively. After 1 year, early-season artificial defoliation generally caused greater growth reduction than natural defoliation. Late-season defoliation yielded opposite results. Trees defoliated artificially in early-season treatments were significantly shorter than control trees irrespective of defoliation intensity, whereas those defoliated late in the season did not differ from controls, except at the highest intensity. Trees defoliated by sawflies, either early or late in the season, were significantly shorter than control trees only at the highest defoliation intensity. The pattern of growth loss in the second year appeared similar to that in the first year. The impact of defoliation was either prolonged neutral or negative, as no compensatory responses on height growth in Scots pine were observed. Timing of the treatment in relation to completion of leader growth, differences in defoliation types, alteration of the photosynthetic capacity due to biomass loss, and the functional role of plant parts defoliated may explain the results observed.

Fifth-instar larval mortality was compared between male and female Choristoneura occidentalis Freeman exposed in the laboratory to sublethal doses of Choristoneura fumiferana (Clem.) multicapsid nuclear polyhedrosis virus (CfMNPV) with or without optical brighteners. More females than males died when the virus was used alone, but differences were not significant. When 1% brightener was added to CfMNPV suspension, differences in larval mortality between males and females were significant for three of the four brighteners tested. In addition, times at which 50% of the larvae died indicated that female larvae died 23 and 39% more quickly than male larvae, respectively, when brightener Blankophor HRS and Tinopal LPW were added to the virus, whereas at times at which 95% of the larvae died indicated that females died 33 and 54% faster than males. Alteration of sex ratio favoring male survival can play a significant role in the biological control of C. occidentalis by the virus.

Results of a 2-year survey in Alberta, Canada, identified a parasitoid fauna of filth flies distinct from that generally reported for cattle confinements in the United States. Twenty-two feedlots were surveyed using freeze-killed sentinel house fly pupae. Parasitism averaged 0.25%. Ten species of hymenopterous parasitoids were recovered. As a percentage of the total number of pupae parasitized, these species were Muscidifurax raptor Girault & Saunders (37.4%), Trichomalopsis sarcophagae Gahan (23.9%), Urolepis rufipes (Ashmead) (18.5%), Muscidifurax zaraptor Kogan & Legner (6.9%), Nasonia vitripennis Walker (6.5%), Trichomalopsis sp. (3.7%) (Pteromalidae), Phygadeuon sp. (2.9%) (Ichneumonidae), Dibrachys cavus (Walker) (0.1%) (Pteromalidae), Synacra sp. (0.1%) (Diapriidae), and an unidentified Braconidae (0.1%). No differences were detected among natural regions of the province. Three categories of seasonal activity are identified which expand on previous groupings of species by their geographic distributions. The abundance of T. sarcophagae and rarity of species of Spalangia Latreille, 1805 are in marked contrast to results of surveys conducted in the United States. This difference suggests that species used to manage populations of pestiferous flies associated with livestock in the United States could be inappropriate for use in Canada.

A survey of larval and pupal populations of the spruce bud moth, Zeiraphera canadensis Mutuura and Freeman (Lepidoptera: Tortricidae), conducted from 1994 to 1996 in eastern Newfoundland, disclosed that the incidence of endemic parasitism by Hymenoptera was up to 50% for Tycherus osculator (Thünberg) (Ichneumonidae), up to 15% for Earinus zeirapherae (Walley), under 3% for Ascogaster (Wesmael 1835) sp. and Clinocentrus (Haliday 1833) sp. (Braconidae), and under 1% for Lamachus (Foerster 1868) sp. and Triclistus (Foerster 1868) sp. (Ichneumonidae). Tycherus osculator, E. zeirapherae, Ascogaster sp., and Clinocentrus sp. represent new distributional range extensions to Newfoundland, and to the nearctic region in the case of T. osculator. The biology of European populations of T. osculator was studied on a natural host, Zeiraphera diniana (Guenée). Only females overwintered and ovarian maturation did not occur until after several months of exposure to near-freezing temperatures. Tycherus osculator successfully parasitized prepupae and pupae of Z. diniana of all ages but, in the laboratory, appeared to prefer pupae. Host feeding by T. osculator was common but not necessary for ovarian maturation. Tycherus osculator imported from Europe attacked and successfully developed within the spruce bud moth host in laboratory screenings. Morphological comparisons indicated that T. osculator reared from Z. canadensis were smaller than those reared from Z. diniana. Tycherus osculator obtained from either Newfoundland or Europe may have potential as a biological control of Z. canadensis in mainland Canada, where it is presently absent.

The within-tree scale dynamics of mass attack by the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, on its host were investigated and quantified. Seven similarly sized Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco (Pinaceae), infested as part of several pheromone-induced infestations, were monitored over an entire attack season. Ninety percent of the attacks on mass-attacked trees occurred within 3 weeks of colonization; the remaining 10% occurred gradually over the remaining 7 weeks of the attack season. Vertical attack distribution followed a Gaussian form that shifted upwards on the bole with increasing attack density. The change in attack pattern associated with increasing attack density was investigated for the central vertical portion of the bole, where most attacks occurred, and where the vertical pattern was least variable. At low density, attacks were randomly distributed. As density increased, the distance between attacks decreased, eventually resulting in a uniform distribution.

We investigated pollen and nectar foraging of honey bees, Apis mellifera L., from pollen-poor and pollen-rich, small and large colonies in blooming highbush blueberry, Vaccinium corymbosum L. cv. Bluecrop fields. The proportion of pollen foragers differed significantly between pollen-rich and pollen-poor colonies after storage levels were manipulated, but foraging and pollen stores returned to similar levels within a week. No differences were found in small colonies, although the proportion of pollen foragers was high (46% and 45% from pollen-rich and pollen-poor colonies, respectively). Only 7.6% of pollen foragers carried Vaccinium sp. pollen in their loads independent of treatment, day, and colony size, whereas 60.8% of nectar foragers carried up to 100 tetrads of Vaccinium sp. pollen on their bodies. The average proportion of Vaccinium sp. pollen carried by nectar and pollen foragers per day and treatment was less than 10%. Our research indicates that when colonies are placed in fields of blooming blueberry flowers, pollen foraging is stimulated in large colonies with stores that are pollen poor, but predominantly for pollen types other than blueberry. This research indicates that nectar foragers are the major visitor of highbush blueberry cv. Bluecrop and suggests that increasing the number of nectar foragers rather than pollen foragers would result in more honey bees foraging on highbush blueberry, in particular cv. Bluecrop.

Our investigation estimates time–temperature relationships and demonstrates the effect of rapid heating on mortality of Caribbean fruit fly, Anastrepha suspensa (Loew). Mature larvae (third instars) in water were exposed to each of seven temperatures (44, 45, 46, 47, 48, 49, and 50 °C) and each of five power levels (11, 27.5, 55, 88, and 122 W) in a research-quality microwave oven. Controls were immersed in water for 30 min and not exposed to microwave energy. Data were analyzed by a probit model with three explanatory variables. The variables were time to reach target temperature, power, and final temperature. Temperature needed to control the larvae increased as power increased. Of the power–temperature levels, the only combinations that resulted in > 99% mortality were the lowest power (16 W) at 49 or 50 °C and 30 W at 50 °C. Time required for > 99% mortality decreased with increased power. Thus, as power delivered to larvae increased and time needed to reach exposure temperature deceased, percent mortality decreased. We conclude that rapid heating imposes serious constraints on the use of heat-induced mortality; this result raises important questions that must be addressed because quarantine security may be jeopardized.

A troglobite species, Quaestus (Quaestus) acuminatus sp.nov., from the Cantabrian Mountains (Province of Asturias, Spain) is described and illustrated. The taxonomic position is discussed and data on its isolation and geographical distribution are given.

Colonies of the honey bee, Apis mellifera Linnaeus, infested with the parasitic mites Acarapis woodi (Rennie) (Acari: Tarsonemidae) or Varroa jacobsoni Oudemans (Acari: Varroidae) require acaricidal treatment to control infestations that could affect colony growth and honey production. We investigated the effects of three acaricides, fluvalinate (formulated as Apistan®), formic acid, and menthol, on honey bee colony population growth, foraging activity, adult worker longevity, and honey production. Effects of in-hive treatments of Apistan® and formic acid were measured by examining colony weight gain, brood survival, sealed-brood area, emerged-bee weight, number of returning foragers, pollen-load weight, and worker longevity. These characteristics were not different between fluvalinate-treated colonies, formic-acid-treated colonies, and control colonies. Adult bee population, brood survival, number of returning foragers, and honey production did not vary among menthol-treated colonies, formic-acid-treated colonies, and control colonies. Sealed-brood area was lower in formic-acid-treated colonies than control colonies, but not different from menthol-treated colonies. Although not statistically significant, formic-acid-treated colonies experienced lower honey production than both menthol-treated and control colonies. Numbers of workers attending the queen in the retinue and queen behaviour patterns were not different after colonies were treated with formic acid.

We have discovered that, contrary to the long-held belief, 1st-instar spruce budworm, Choristoneura fumiferana Clemens, do feed. They display red alimentary tracts if they are provided with diet containing the red dye amaranth. They graze on the surface of balsam fir needles sprayed with rhodamine and ingest the fluorescent material, which can be detected in the frass pellets deposited inside the hibernacula. When emerging 1st instars were allowed to crawl on the inside surface of a glass tube coated with the polyhedral inclusion bodies of a recombinant C. fumiferana virus containing the gene for the green fluorescent protein, the larvae showed the characteristic green fluorescence, indicating that not only had they ingested the occlusion bodies but also the virus had replicated and infected different tissues. Similar results were obtained with the jack pine budworm, Choristoneura pinus pinus Freeman, which has an identical life history. The advantages of early-instar intervention to minimize defoliation by using control agents such as the ecdysteroid agonist, tebufenozide (RH-5992, Mimic® formulation), are discussed.

Monoctonus paulensis (Ashmead) was reared in the laboratory on the four nymphal instars of the pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphidoidea: Aphididae). Females frequently laid clutches of two eggs during a single ovipositor probe; however, clutches of more than two eggs were rare. The time needed to capture and position an aphid for oviposition increased with aphid instar but was independent of the number of eggs laid. Oviposition time was proportional to egg number, which shows that eggs were laid one at a time rather than clumped together as a package. Intensity of parasitism (i.e., number of eggs per parasitized host) increased with host instar but declined with the number of hosts attacked in quick succession. Our results suggest that clutch size in M. paulensis is not accidental but controlled by the female.

Following a 3-year period of high populations of the little spruce sawfly, Pristiphora abietina Christ, a monophagous species infesting Norway spruce, Picea abies Karst., we compared variations in foliar nutrients (nitrogen, water, soluble carbohydrates, starch) and potential defensive compounds (fiber, quinic and shikimic acids, tannins) of trees that had been subjected to high or very low levels of defoliation. During the time of needle expansion a substantial decline in leaf quality occurred: nitrogen, water, and carbohydrate levels decreased, whereas fiber and starch concentrations increased. Allelochemicals such as tannins and organic acids, however, peaked at bud break and then rapidly declined. More heavily attacked trees had higher nitrogen, water, and fiber contents but lower starch and organic acid concentrations than lightly attacked trees. The needle tannin content was significantly lower in heavily attacked trees throughout the period of larval feeding. Needle tannin levels and the nitrogen to tannin ratios seem to be the most probable traits to distinguish sawfly-resistant from sawfly-susceptible Norway spruce trees.

Investigations of preimaginal development in Tiphodytes gerriphagus Marchal reveal two larval instars, based on counting exuviae and comparing mandible length during development within Limnoporus dissortis Drake & Harris eggs. Tiphodytes gerriphagus eggs are stalked, as is typical of scelionids, and are 282.6 ± 3.48 μm (mean ± SE) long. The chorion ruptures at 8–9 h postoviposition and releases a nonfeeding embryo into the host. Feeding begins at 18–20 h postoviposition, after the embryonic cuticle is shed and a fully differentiated and active larva is released. The first larval stage is teleaform and lasted up to 5 days postoviposition, and its total length increased from 183.6 ± 3.35 to 517.0 ± 14.67 μm. The second larval stage is hymenopteriform and lasted from 5 to 13 days postoviposition, and grew from 920.2 ± 24.65 to 1352.4 ± 11.89 μm total length before pupating. The pupal period lasted about 11 days, with male pupae being shorter and thinner than female pupae. These findings differ from previous descriptions of T. gerriphagus, and it is suspected that the first instar was mistakenly divided into two stadia. The sex ratio under laboratory conditions was female biased (22% males), and males were smaller but did not emerge significantly earlier than females.