We studied the ovipositional behavior of the citrus blackfly (CBF), Aleurocanthus woglumi Ashby, and found several plant species (mango, pink trumpet, and kumquat) to be as attractive as Citrus spp to ovipositing CBF at low densities. There is a significant (P < 0.01) positive correlation between the attractiveness of various host plants in our tests and the frequency of CBF occurrence on these plants in field surveys The host range of CBF increases with increasing CBF density. Oviposition by CBF on preferred hosts appears to occur at all CBF densities and is independent of their frequency in the environment We also found that CBF adults appear to be attracted to plant material reflecting light in the 500–600 nm range and it appears that this is the only long-range attractant operative.

The functional response of the predacious mite Phytoseiulus persimilis Athias-Henriot to increases in the prey density of adult female Tetranychus urticae Koch was examined. Previous studies on artificial substrates have described the functional response curve of P. persimilis to adult female prey as dome-shaped, because as prey density increased the predator was disturbed by prey activity.

An experiment to determine the effect of artificial and natural substrates on the activity level of T. urticae was conducted. T. urticae showed a significant increase in activity on artificial substrates of plastic and waterproof paper compared with a substrate of excised bean leaf (Phaseolus vulgaris L.). Since prey activity was significantly influenced by substrate, the functional response of P. persimilis to adult female T. urticae was re-examined. P. persimilis exposed to various densities of T. urticae on excised bean leaf disks (5 cm2) showed a functional response curve having a curvilinear rise to a plateau as prey densities increased from 0.2 to 10.0 prey/cm2.

The functional response curve predicted by Holling’s disk equation did not differ significantly from the observed functional response curve.

The rate of successful search and the handling time predicted by the disk equation were 0.194 and 10.34 h respectively.

Sex attractant traps for males of the clover cutworm, Scotogramma trifolii (Rottenberg), on farms in southern Alberta caught more moths within crops or on fallow than those near or within the farmyards except for traps immediately on the south side of the yard For males of the army cutworm, Euxoa auxiliaris (Grote), two trap placements in open areas were more effective than locations within the farmyard, again with the exception of the traps on the south side of the yards. Traps 2 m high caught significantly fewer moths than those at 1 m or ground level and the crop in which the trap was placed had no significant influence on catch of either cutworm.

The vernal migration routes of the eastern population of the monarch butterfly (Danaus p. plexippus L.) in North America were plotted from data resulting from the recapture of migrants alar tagged in the overwintering site of the Neo-volcanic Plateau of Mexico. One migrant, which had been alar tagged at Decorah, Iowa, on 3 September 1973, and recaptured 7 months later on 8 April 1974 at Richmond, Texas, led to the conclusion that this particular migrant had flown to the Mexican overwintering site and was recaptured on its return vernal flight. This recapture also gave data indicating that it was not returning to the original breeding area, from which it is concluded that although some migrants may return to the original breeding grounds many may not do so.

Types of nine species of Sarcophagidae are redescribed, two species belonging to the tribe Microcerellini, six to Johnsoniini, and seven to Sarcophagini; Harpagopyga rufipes Dodge is transferred to Notochaeta. In addition to the female holotype, the male of Harpagopyga diversipes (Coquillett) is also described.

A new species of Grylloblatta from the Coast Mountains of British Columbia and two new subspecies of Grylloblatta campodeiformis Walker from northern British Columbia are described and figured. The distribution of the species groups from the Rocky Mountain and Coast–Cascade Cordillera are indicated. An interpretation of the present distribution as a result of late Pleistocene and Holocene geological and climatic events is presented.

Twelve female Aedes trivittatus were captured between 5 July and 8 September 1976 at Knowlton and St. Pie, Quebec Another female of this species and a male Culiseta inornata were caught on 28 September 1977 at Henryville These two species are new mentions in Quebec.

This paper presents results of a multidisciplinary optimization study on the impact of Lygus hesperus Knight on cotton in the Great Central Valley of California. The results of the empirical studies indicate that lygus bug is not a serious pest of cotton under most circumstances and, furthermore, illustrate why cotton yield enhancements have occurred when their populations have not been controlled. An economic analysis of these results sheds some light on the concept of economic threshold. In particular it is shown how in this case an economic threshold exists even if the costs of pesticides are zero. The theoretical implications of these results are quite general.

A theory for the population behavior of the eastern blackheaded budworm is presented. The qualitative properties and key processes of the system are identified and a description of the theory as a simulation model is given. Two domains of stability exist for the insect; one is caused by bird predation, the second by the effects of food limitation. The model predicts that the budworm’s cyclical population fluctuations are produced by the disappearance and reappearance of these stable domains and consequent movement of densities to new levels. Parasitism is identified as the principal mechanism causing this behavior. A qualitative comparison of model behavior with historical behavior is made and a critical field experiment to test the validity of the theory is proposed. Finally it is suggested that the population behavior of many forest defoliators may be explained using this theory.

Scanning electron micrographs of balsam wooly aphid, Adelges piceae Ratz., show ribbon-like wax secretion in the dorso-median, marginal, and inter-tergal regions. Longitudinal grooves in the ribbons indicate that secretions from a row of cells fuse together to form bands of wax. Most of the ribbons appear as extensions of the tergal sclerites. Post-notal plates are conspicuous in the dormant first instar, and in the adults characteristic wax plates with crater-like pits are evident. The chemistry of wax in related species and a rationale for control using juvenile hormone analogs are discussed.

A single 0.3 ppm injection of methoxychlor into the Athabasca River, Alberta on 4 June 1974 for 15 min caused catastrophic drift for a distance of over 400 km, and a subsequent large decrease in the drifting population. This decrease, when expressed as a percentage reduction from pretreatment drift, is in close agreement with percentage reduction of standing crop recorded by other sampling methods. The time required for the pesticide to affect different species varied considerably but was not related to the mode of feeding. Methoxychlor residues above ambient levels in water were recorded in all the invertebrate populations sampled. Caged animals had significantly different residues than the natural populations. The use of caged animals as indicators of environmental damage is therefore questioned.

Traps baited with the sex pheromone of the bertha army worm moth, Mamestra configurata (Walker), were operated at 36 sites across the prairie provinces in 1976 and 1977. They captured ca. 15 times as many bertha moths as did light traps and were considered to constitute a useful method for detection of adults of this species.

A rotating wheel olfactometer was adapted for laboratory evaluation of oviposition attractants for the navel orangeworm, Paramyelois transitella (Walker). The bioassays were conducted inside a large screen cage in a glasshouse with controlled temperature and humidity. Flying female moths responded to attractant volatiles emitted from egg traps on the olfactometer and oviposited on the surface of the traps.

Further experiments were done in an attempt to ascertain the significance of the mandibular glands of nurse bees in female caste differentiation. Groups of 200, 10-day-old nurse bees, with their mandibular glands removed, fed female larvae for 80 h in plastic queen cell cups in the laboratory. After this, each larva finished feeding in a 4-day-old queen cell containing "royal jelly"; final development occurred in an artificial pupation dish. Because four adults, classified as "queenlike intermediates," were reared it appears that (1) mandibular gland secretion is less important as a larval food than that of the hypopharyngeal glands, and (2) if a "queen determining substance" exists the mandibular glands are not its only source.

Females of Muscidifurax zaraptor K. & L. produce a smaller percentage of female progeny as the ratio of ovipositing females to hosts (house fly pupae) increases. Delays in oviposition are apparently responsible for the sex ratio change, because they reduce the percentage of fertilized eggs, i.e. female eggs, that the parasites lay. Delays increase in frequency as the parasite:host ratio increases, and result mostly from interference among the ovipositing females; the interference is mostly or entirely physical. Solitary females of M. zaraptor produce slightly fewer though not significantly fewer female progeny when low host densities delay oviposition; more tests would be required to confirm this effect. There is no evidence for differential survival of the male and female parasite larvae on superparasitized hosts.

An ecological study of ground nesting sparrows has been underway for several years at Isle Verte (15 km east of Rivière-du-Loup) Québec, in a hayfield–salt marsh ecotone with an average density of six ground nesting passerine pairs per hectare. In both 1976 and 1977 one brood of Savannah Sparrow, Passerculus sandwichensis, containing four and three nestlings, respectively, were observed to be infested with dipterous larvae which have been identified as Protocalliphora hirudo Shannon and Dobroscky. This constitutes the first record of this parasite in Québec and the first time that the Savannah Sparrow has been recorded as a host. Protocalliphora hirudo was originally considered as a species restricted to western North America (Shannon and Dobroscky 1924) but has since been collected from an unidentified sparrow in Massachusetts (Johnson 1925), on Chipping Sparrow (Spizella passerina) nestlings in New York (George and Mitchell 1948), and the Vesper Sparrow (Pooecetes gramineus) in Ontario (Bennett 1957). Bennett (1957), in his study of Protocalliphora spp. in Ontario, described P. hirudo as an ubiquitous species although most frequently found attacking ground nesting birds in open habitats similar to our study area.