Females of Nasonia vitripennis (Walk.) (Hymenoptera: Pteromalidae) laid fewer eggs on parasitized than on unparasitized pupae of the house fly, Musca domestica L. Chemical and/or physical conditions of parasitized pupae are detected by the female’s ovipositor, causing this restraint. These conditions may in part result from the host’s death, caused by earlier parasitization, but other factors are also involved. These may include venom injected by the female parasite before she lays, and internal injury to the host resulting from insertion of the parasite’s ovipositor. The female parasite does not discriminate because of physical or chemical traces on the surface of parasitized puparia, of eggs or a surface wound on the pupa, or of absence of heart beat in the pupa.

Agrilus anxius was described by Gory (1841), and later given the name “bronze birch borer” by Chittenden (1898). It was recently separated from a closely allied species attacking poplar, A. liragus (Barter and Brown, 1949; Smith, 1949). The borer is native to North America and occurs apparently throughout most of the range olf birch from Newfoundland to British Columbia, and south to New Jersey, Ohio, and Colorado (Barter and Brown, 1949; Fisher, 1928).

Populations of Dendroctonus ponderosae Hopk. aggregate on pine trees in response to a combination of host- and insect-produced volatiles. Release of the insect-generated volatiles by defecation coincides with the release of host volatiles as resin exudes from the galleries initiated by the female beetles. When tested with oleoresin under field conditions, synthetic trans-verbenol, the major insect pheromone, was highly attractive to both sexes of D. ponderosae. Also, emergent female Dendroctonus brevicomis Lec. and Dendroctonus frontalis Zimm. crushed to powder at −70 °C were attractive; emergent females of both species are known to contain large amounts of trans-verbenol. Trans-verbenol per se, however, was not attractive to walking or flying D. ponderosae.

Experiments show that A. tepidariorum selects sites for web building by a series of movements that are random with respect to the distribution of its prey. If selected sites fail to yield an adequate supply of prey they are quickly abandoned. If adequate supplies of food are forthcoming at a site, random movements cease and the site is systematically searched by filling the area with web. Light plays no part in the selection of web sites, but other extrinsic features, for example air currents, play an important role.

The effects of damage by natural infestations of the flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) on field plots of canola, rape (Brassica napus L.), and yellow mustard (Sinapis alba L.) are described. Damage occurred primarily during the first few weeks after emergence: seedling mortality was high during the first week and growth was reduced during at least the first 2 weeks. This early damage delayed plant development, caused unevenness in height and maturity, and reduced seed yield and raised the chlorophyll content of the seed.

Comparison among tests and treatments showed that a later-seeded test suffered less damage, and that carbofuran-treated plots were better protected than lindane-treated plots although the latter suffered slightly lower plant mortality. Yellow mustard showed a high level of resistance to flea beetle damage in comparison to rape and canola. Small differences in susceptibility were detected among three cultivars of B. napus.

A simple age-specific energetics (calories or biomass) model for the growth and development, reproduction, respiration, ageing, and intrinsic survivorship as a function of temperature and per capita energy availability for pea aphid (Acyrthosiphon pisum (Harris)) is reported. The ratio of energy supply–demand is used to scale all of the rates in the model. The maximum demand for energy based upon current state values is used to drive the Frazer–Gilbert functional response model (i.e. food acquisition), which is a component of the metabolic pool model used to assimilate energy to growth, reproduction, respiration, and egestion. The extensive data sets on pea aphid energetics published by Randolph et al. (1975) were used to develop the model. As the model estimates reproduction (Mx) and survivorship (Lx) values, extensive published age-specific life-data sets on pea aphids are used to test it. The results suggest:

(1) the lower thermal threshold for development is raised and the upper threshold is lowered as food resources are decreased

(2) the temperature-dependent rate of development is slowed with decreasing energy resources

(3) the size of individuals and reproduction become smaller as temperature approaches the upper and lower thermal thresholds.A simple model for multitrophic level interactions incorporating the acquisition and assimilation functions is presented.

Although a virus disease of the larch sawfly, Pristiphora erichsonii (Htg.), has not been discovered, polyhedrosis viruses of several other Tenthredinids are known. They have been used to control infestations of two introduced species: the European spruce sawfly, Diprion hercyniae (Htg.), (Bird, 1954) and the European pine sawfly, Neodiprion sertifer (Geoffr.), (Bird, 1950, 1952, 1953; Dowden, 1953). Unfortunately, the viruses of these, as well as the viruses of several other species tested, are not pathogenic to the larch sawfly. Some viruses, however, appear to he pathogenic to more than one species. J. M. Burk of this laboratory found, for example, that a polyhedrosis virus affecting the native jackpine sawfly, Neudiprion americanus banksianae Roh., is pathogenic to N. sertifer, N. nanulus Schedl, and D. hercyniae.

Superparasitism and multiple parasitism of the pea aphid, Acyrthosiphon pisum (Harris), by the solitary hymenopterous parasites Aphidius smithi Sharma & Subba Rao and Praon pequodorum Viereck were studied in the laboratory. In intraspecific competition, an older larva usually eliminated a younger one; exceptions to this rule depended on the relative age difference and developmental stage of the competitors. In interspecific competition, P. pequodorum was intrinsically superior to A. smithi, regardless of the latter's age. The stage of host parasitized and the number of competing larvae had no significant effect on the outcome of the contest. A. smithi females discriminated against aphids previously parasitized by a conspecific female or by P. pequodorum, the degree of oviposition restraint increasing with the time between ovipositions. P. pequodorum females attacked aphids already parasitized by A. smithi, regardless of the age of the Aphidius larva, but avoided oviposition when the aphid contained a Praon larva or embryo. The rate of embryonic development is shown as a major factor in contest-type competition between first-stage larvae.

Monoterpene production, inner bark carbohydrate concentrations, and fir engraver attacks on grand fir were monitored for 3 years following Douglas-fir tussock moth defoliation. Monoterpenes were reduced for 2 years following defoliation. Defoliation caused a reduction in total sugars the first year following defoliation and a reduction in starch the second year. Total sugars and the previous year’s starch concentrations were positively correlated with monoterpene production. The trees which produced the least amounts of monoterpenes were the ones successfully attacked by the fir engraver.

The morphology and fine structure of the maxillary and mandibular stylets of the green peach aphid, Myzus persicae (Sulzer), are described from sections, whole mounts, and two-stage replicas. The mechanisms of penetration of the host plant are discussed.

Since the monumental work of Rose (1938) on the essential amino acids for growth in the rat, similar studies have been made on other vertebrates. It has been shown that most of these animals have the same pattern of amino acid requirements for growth of the immature form and for maintenance of nitrogen equilibrium in the adult. The amino acids usually required are arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophane, and valine. These studies have been adequately reviewed in recent texts (Bourne and Kidder 1953, Albanese 1950).

More than 40 species of insects and arachnids attack Panonychus ulmi (Koch), Tetranychus urticae Koch, T. canadensis (McGregor), Bryobia arborea Morgan and Anderson, or Aculus cornutus (Banks) in peach orchards of the Niagara Peninsula. The most effective predators attacking P. ulmi are Typhlodromus caudiglans Schuster, Haplothrips faurei Hood, Stethorus punctillum Weise, and Chrysopa spp. Peach orchards lack the predatory mirids characteristic of apple orchards. A condition, presumably disease, caused heavy mortality in one year. Endemic densities of P. ulmi are maintained in that state by predators, chiefly T. caudiglans, that subsist to a considerable extent on other sources of food, whereas epidemics of P. ulmi are reduced largely by other predators, chiefly H. faurei and S. punctillum, that increase in numbers by feeding on the mite during its period of rapid population growth but exert their greatest effect later in the season by destroying the winter eggs.

An analytical method for the description of intrinsic variability in insect development rates for incorporation in phenology models is presented. Two sets of experimental data are used as examples. The method is easy to apply, can describe data accurately, produces highly realistic simulations of insect development, and is amenable to the simulation of age-dependent mortality, feeding, and reproduction. The method was developed for univoltine insects with discrete generations, but it can also be applied to multivoltine species with overlapping generations. A modification of the method to handle small samples is also discussed and applied to data.

In four studies with loblolly pine bolts over a 2-year period, absence of the normal complement of mycangial and ectodermal fungi, or absence of mycangial fungi alone, caused a significant decrease in number of progeny, progeny/gallery, progeny/cm of gallery, and ratio of increase of Dendroctonus frontalis Zimmerman. Initial emergence of progeny was delayed 13 to 24 days. Absence of fungi had no effect on number of successful attacks, length of ovipositional gallery, and number of egg niches/cm of gallery.

Most scolytids occupy temporary habitats. Migration, therefore, forms an important part of adult behaviour. Since the extent of migratory movement is positively correlated with the degree of impermanence of the species’ habitat, differences in the behaviour associated with migration must be expected to occur between species. Furthermore, the behaviour of individuals must change in relation to changes in physiology associated with migration and reproduction. These changes have been demonstrated in laboratory studies, and the results suggest that the phenomenon of secondary attraction observed among scolytids may have evolved in conjunction with their utilization of transitory habitats.

This study consisted of two field experiments designed to assess the effects of acaricide treatment timing on the mean abundance of the mite Varroa destructor Anderson and Trueman and its impact on honey production and colony survival in honey bees, Apis mellifera L. (Hymenoptera: Apidae). In the first experiment, replicated colonies with different levels of infestation by V. destructor were given one of six treatments: untreated, with a low level of infestation by V. destructor; untreated, with a moderate level of infestation by V. destructor; exposed to fluvalinate for 42 days; exposed to two applications of Perizin®; or exposed to four applications of a pour-on formulation of formic acid at 4- or 10-day intervals. The six treatments were applied in either spring or fall. In experiment two, replicated colonies with a high level of infestation by V. destructor were left untreated, exposed to fluvalinate for 42 days, exposed to five applications of formic acid at 7-day intervals, or exposed to an equivalent amount of formic acid applied as a slow-release formulation. For each experiment, V. destructor densities, measured by alcohol wash, and colony survival were monitored for 1 year, and honey production was assessed in the year in which the spring treatment was applied. The results showed that all of the acaricide treatments were effective in reducing the mean abundance of V. destructor. However, efficacy varied with season. Fluvalinate was effective in controlling varroa under either spring or fall treatment conditions. Fall applications of Perizin® provided better control than spring applications. Formic acid provided consistent control of V. destructor in spring applications, regardless of the interval between treatments or whether pour-on or slow-release formulations were used, but was ineffective in the fall. Honey production was improved by spring acaricide treatments in both years. When the mean abundance of V. destructor was 0.02 ± 0.005 mites per bee (2 mites per 100 bees) in mid-April, honey production increased from 66 ± 17 kg per colony in untreated colonies to up to 116 ± 23 kg per colony in colonies treated with acaricide. When V. destructor levels were 0.21 ± 0.02 mites per bee (21 mites per 100 bees) in mid-May, spring acaricide treatments increased honey production from 1.3 ± 2.3 kg per untreated colony to up to 48 ± 17 kg per acaricide-treated colony. For the prairie region of Canada, producers will need to assess colonies in both spring and fall and treat when the mean abundance of V. destructor is more than 0.02 mites per bee (2 mites per 100 bees) in spring to prevent losses in honey production. Producers should treat when the mite level is greater than 0.04 mites per bee (4 mites per 100 bees) in late August to early September to prevent fall or winter colony loss. In this study, tracheal mite (Acarapis woodi (Rennie)) (Acari: Tarsonemidae) levels were very low, so interactions between mites were not studied. If both tracheal and varroa mites are present, lower fall thresholds might be required. In the absence of tracheal mites, colonies with varroa mite levels of more than 0.17 mites per bee (17 mites per 100 bees) in late fall experienced significant winter loss.

The influence of various aspects of Malaise trap design on efficiency in collecting various groups of Hymenoptera was compared using commercially available traps. The influence of fine and coarse mesh sizes and the importance of the incorporation of pan traps into the design were evaluated in two sampling periods in an old dune community at Pinery Provincial Park in southern Ontario. Numbers of individuals collected in Malaise trap heads and pan traps were presented for each paired comparison of mesh size (fine and coarse) and location (top and bottom of a hill) for various families of Hymenoptera. A graphical analysis of the normalized catch data for more inclusive groupings, viz. Symphyta, Aculeata, Ichneumonoidea, and microhymenoptera, was presented. The major results of these comparisons were as follows: (1) pan traps were an important component of efficient Malaise traps, especially for Aculeata and microhymenoptera; (2) coarse mesh was more effective in collecting Aculeata; (3) coarse and fine mesh were both effective in collecting Ichneumonoidea; and (4) fine mesh was more effective in collecting microhymenoptera. There was an interaction effect between the type of trap used and groups collected and it was not possible to maximize simultaneously the collection of all groups of Hymenoptera. The use of various mesh types and a trap design that incorporates pan traps was recommended.

This paper deals with the influence of bark moisture and temperature on the hehaviour of the egg-laying female within the host. Fecundity of the insect will he discussed, as well as internal changes associated with the behavioural pattern. The life-cycle, brood development, and time of flight was described in Part I of the present series. The behaviour during mating, egg laying, and gallery construction were described earlier (Reid 1958b).

Considerable evidence substantiates the idea that native pests can be controlled by parasites and predators of allied species and genera. In a survey of 66 pest species, which were successfully controlled by biological means and for which the habitats of all species could be verified, it was found that 39% were controlled by an introduced parasite or predator of an allied species or genus. Although relatively few attempts have been made to control native and imported pests with parasites and predators of species allied to the pest species, the proportion of successes is surprisingly high. Employing these species has certain advantages, especially in the control of imported pests, because no ecological homeostasis has evolved and the association between the parasite and host (predator and prey included) is new.

In laboratory tests, Melanoplus sanguinipes (Fab.) was susceptible to infection by Beauveria bassiana (Bals.) Vuillemin conidia. Infection occurred independently of the relative humidity (RH) (12, 33, 76, 100% RH). No significant difference was observed in the final percentage mortality of the treated grasshoppers and in the lethal times (LT50)(P > 0.05) under the RH conditions studied. However, the daily rate of mortality after treatment was higher at 76% RH than at 33% RH. High natural mortality occurred at 100% RH.

At 100% RH, treatment with B. bassiana was associated with an outgrowth of microorganism that created septicemic conditions in the absence of the characteristic symptoms of mycosis. Below 100% RH, mycelial growth on cadavers was never observed, even though partial or total insect mummification occurred, and a pink body coloration on approximately 80% of the insects indicated Beauveria as the killing agent. Once transferred to 100% RH, no more than 5% of the treated grasshoppers exhibited external mycelial growth.

The microenvironment at the cuticular level of the grasshopper allows expression of conidial pathogenicity regardless of ambient RH. Hence, together, these observations suggest the feasibility of field testing with B. bassiana as a bioinsecticide against M. sanguinipes in semi-arid climatic areas.