Environmental instabilities may be grouped into three broad categories each with different conseqences for the organism which has to survive the stress of these instabilities. On one side are irreversible changes of the environment which will lead to complete adaptive compliance or conformity of the population, brought about by natural selection. On the other side are short-term recurrent instabilities, fluctuations, or oscillations; if their cycle is short enough so that all phases are experienced by all individuals of each generation, natural selection will promote the ability of each individual to withstand the whole range of environmental recurrent fluctuations. Between these extremes are recurrent instabilities that are not experienced by all individuals, or by each generation; here natural selection will evolve mechanisms that prevent the population from conforming with any temporary selection pressure. Polymorphism is such a mechanism, specifically polymorphism based on a gene potency balance system modelled on the same principles as the system that determines sex, the most common example of polymorphism. Instances of such polymorphism in a genus of tortricid moths include haemolymph pigment, adult wing colour, and rate of larval development. The latter exemplifies polymorphism of a quantitative character.

About the year 1890 the plant Cordia macrostachya (Jacq.) Roem. and Schult. was accidentally introduced into Mauritius with a consignment of sugarcanes from the West Indies. Later Cordia was spread artificially around the island in an effort to encourage the increase of Tiphia parallela Smith. This parasite was introduced into Mauritius as a possible control agent for the sugarcane root-grub, Clemora smithii (Arrow), and it was found that adult Scoliids fed at the inflorescences of Cordia. (Box 1928). Since that time Cordia has spread considerably and has become a serious pest in Mauritius (for details see Wiehe 1946).

Varroa destructor Anderson and Trueman females were placed in contact with queen, worker, and drone brood cells of Apis mellifera L. that were soon to be sealed. In a non-choice test, V. destructor adult females were introduced into a comb containing either queen or worker brood cells; 0.62 and 18.28% of the mites entered the queen and worker brood cells, respectively. Only 1 of the 11 mites that entered queen brood cells oviposited, laying a single egg. In another test, brood cells were combined in the same comb in a 1:25:3 queen:worker:drone ratio. The percentages of egg-laying mites in queen, worker, and drone brood cells were 16.66, 61.86, and 79.06%, respectively. When queen, worker, and drone brood cells were combined in equal proportions (33.3:33.3:33.3), percent infestation was significantly different among queen (3.25%), worker (49.12%), and drone (90.07%) brood. Multiple infestation was found in drone brood cells but not in others. Also, mites were inoculated into sealed queen cells. These cells contained either one or two mites (either at the egg or protonymph stage). Conversely, in a simultaneous test with worker brood cells, the offspring per foundress mite included a mean of three individuals (either at the egg, protonymph, or deutonymph stage). It is concluded that V. destructor can infest queen, worker, and drone brood cells, but drone brood cells are preferred; in addition, queen brood cells do not provide an optimal environment for reproduction because it causes a delay in mite oviposition and (or) progeny development.

The ash leaf cone roller, Caloptilia fraxinella (Ely), is a leaf-mining moth that has recently become a significant pest of horticultural ash, Fraxinus L., species in communities throughout the western prairie provinces of Canada. The study examines the spatial and temporal within-host distribution of immature stages of C. fraxinella on green ash, Fraxinus pennsylvanica Marsh. Female C. fraxinella showed a preference for oviposition sites in the lower canopy and on the south side of the tree at the beginning and middle of the 3-week oviposition period, respectively, but no preference at the end of the period. Oviposition was constrained temporally and occurred mainly just after green ash bud flush. Immature stages were sampled throughout the growing season, and measured widths of larval head capsules showed five instars. Fourth-instar larvae disperse from the mined leaflet to a new leaflet, roll it into a cone, and pupate. Neither canopy height nor ordinal direction affected the position of larvae in the canopy, but numbers of immature stages varied by tree within a site. Female and male moths eclose from rolled leaf cones synchronously throughout the emergence period. The study provides some of the basic biological information required to design an integrated pest management program to target this emerging pest of horticultural ash trees.

Studies on insects affecting seed and forage production of legume crops were begun in eastern Ontario in 1951. Since little was known of what species of insects were of economic importance in these crops in this area, the primary objects of the studies were to determine what species of insects damage the forage crop legumes, their seasonal occurrence and abundance, and something of their importance. Observations were made as well on some of the beneficial insects found in association with the crops.

Fifteen life tables were compiled from population and mortality data collected in the Quinte area of eastern Ontario during the 5-year period, 1972–76, that spanned the rise and fall of an outbreak of the alfalfa weevil, Hypera postica (Gyll.).

Components analysis of the data showed that a disease of the feeding larvae caused by Entomophthora phytonomi Arthur, a fungus new to the insect in North America, was the principal determinant of intrageneration survival. Multivariate analysis of the separate mortalities, expressed as k-values, confirmed that this agent was the key factor governing population trends of the weevil and was mainly responsible for its population decline.

Examination of the properties of the various mortality factors showed that E. phytonomi was density dependent but overcompensating. Other agents, including the parasitoids Bathyplectes curculionis (Thom.) and Tetrastichus incertus (Ratz.) acted in a density independent manner and contributed little to population trend.

A protease digestion technique for preparing insect chemosensilla for observation at high magnifications under the Scanning Electron Microscope is described. Treatment with protease for 30 min or more followed by sonication removes material normally obscuring pores and surface grooves. This allows surface details and terminal valves to be seen under the SEM. The chemoreceptive hairs of insects can now be rapidly classified as having primarily a contact or olfactory function based on the presence or absence of visible terminal openings on some of the sensilla. Trypsin treatment was less useful, and neuraminidase had little effect. These results indicate that the material extruded onto the surface of the sensillum is proteinaceous.

The western Canadian species of Athous are described and illustrated in detail. Notes are given for the other western nearctic species including the description of a new subspecies, A. rufiventris brighti, from Arizona. A key to the species and subspecies north of Panama is presented.

A lectotype is designated for Athous varius Lane. Several new synonymies are proposed: Athous excavatus carmeli Van Dyke is a synonym of excavatus (Motschulsky) and excavatus angelicus Van Dyke is a synonym of axillaris Horn; orophilus Harold (= montanus LeConte) and nugalis Fall are synonyms of nigropilis Motschulsky.

Two names have been overlooked by North American cataloguers: Athous fallianus Reitter, an unnecessary replacement name for Athous aterrimus Fall and which now becomes a new synonym of aterrimus; and Athous debilitatus Candèze, a necessary replacement name for Athous debilis LeConte and which is now recognized as a valid species, Conoderus debilitatus (see section on species previously described in Athous).

A key, based on morphological characters of adult males, separating six traditionally recognized conifer-feeding Choristoneura species, C. pinus Freeman, C. lambertiana (Busck), C. fumiferana (Clemens), C. occidentalis Freeman, C. biennis Freeman, and C. orae Freeman occurring in Canada and Alaska is provided and illustrated. The newly discovered morphological features, the aedeagus of C. fumiferana and C. pinus with a short apical spine and with many microscopic spicules on the distal half, are used to separate these two species from their western allies C. occidentalis, C. biennis and.C. orae.

Our objective was to test the hypothesis that late-instar nymph, male, and (or) female German cockroaches, Blattella germanica (L.), use sonic signals for intraspecific communication. A digital-recording system was assembled that consisted of a computer equipped with data-acquisition hardware and software, microphones sensitive to sonic and ultrasonic frequencies, and speakers capable of emitting sonic and ultrasonic sound. Sound was repeatedly recorded from groups of five nymphs, five virgin males, or five virgin females. Click-type sounds were commonly present in recordings from nymphs, and consisted of sound pulses of about 10-ms duration and peak frequencies of 7, 9, 11, and 14 kHz. Similar "clicks" were found in recordings from females. In replicated binary choice arena bioassays with individual laboratory-reared insects, played-back "clicks" from nymphs or females or computer-generated artificial clicks attracted nymphs but not males or females. These results provide the first evidence that sonic signals are part of the complex B. germanica communication system.

Winter cocoons have been described in several species of Chironomidae (summary in Danks 1971, table V; see also Madder et al. 1977). The larvae are tightly folded within these closed cocoons in ways more or less characteristic of the species. Usually the walls of the cocoons are thicker than those of the tubes within which larvae are active in summer and less particulate matter is incorporated into them. Most larvae of two species studied earlier in Ottawa (Danks 1971) constructed their winter cocoons only after surface ice had formed.

A biological study of Telenomus coelodasidis Ashm. revealed a close temporal synchronization between this egg parasitoid and its primary host, Heterocampa guttivitta (Wlkr.). The wasp reproduced parthenogenetically in the laboratory and completed development in unfertilized host eggs. Wasp activity was greatest at relatively low temperatures, and longevity was significantly greater when individuals were provided with food. The second and third stage larvae and the pupa are described, as well as the sequence of visible changes occurring in parasitized host eggs. The egg stage of H. guttivitia should be sampled about 5–7 days after peak oviposition by the host, and eggs held for 4–6 days to obtain an accurate estimate of apparent mortality.

On June 8, 1910, in the woods near Brookline, Massachusetts, W. F. Fiske, then in charge of the Gipsy Moth Parasite Laboratory, collected an adult of the rare beetle Chromatia amoena Say (determination by the late Dr. E. A. Schwarz). Having no killing bottle, he placed the specimen in a match box. On the following day he found that the larva of a Dipternus parasite had issued and pupated in the box. The adult failed to emerge and the puparium was unfortunately discarded. In an attempt to determine something of the life history of the parasite, I dissected the dead host and found in it the first and second stage mouth hooks and the second stage posterior spiracles which were of such unusual structure that they seemed worth while describing. A short paper on the parasite was therefore published in 1913l in the journal published by Professor F. Silvestri, in whose laboratory I was then working.

Samples of the egg, larval, and pupal stages of the saddled prominent, Heterocampa guttivitta (Walker), were obtained from infestations of this defoliator in six northeastern states. Seventeen species of primary parasites were recovered, 11 are new records for this host. A key to adult parasites is presented.Apparent parasitism of the egg stage by Telenomus coelodasidis Ashm. and Trichogramma minutum Riley varied from 30 to 76% and 1 to 20% respectively. Aggregate apparent mortality ranged from 40 to 78%. As a rule, egg parasitism was highest in the upper crown of both sugar maple and beech. The developmental stages of parasitized eggs are described and illustrated.

Two species of larval parasites were recovered: Phobocampe pallida (Cush.) from instar III and Eulophus anomocerus (Crawford) from instar V. Parasitism by each species was always less than 1%.Cratichneumon sublatus (Cress.) was the only pupal parasite found in all of the infestations examined. Parasitism ranged from 1 to 17% under outbreak conditions to as much as 32–57% the year following a collapse of the host population. A new species of Patelloa (Tachinidae) was recovered from pupae in Maine and New York. Parasitism by the latter ranged from 3 to 7%. Ten species of Ichneumonidae and one species of Sarcophagidae were also recovered from the pupae.

The name Enaysma Delucchi, 1954 is synonymized with the name Achrysocharoides Girault, 1913. Achrysocharoides is divided into two species-groups, guizoti and gahani. Fifteen North American species are recognized, including five that are new: A. reticulatus, A. bisulcus, A. albus, A. tetrapunctatus, and A. intricatus. A key to species, host lists, and distributions are included.

Entomophthora phytonomi Arthur, a pathogen recognized for many years under the name Entomophthora sphaerosperma Fres. as an important natural control agent in populations of the clover leaf weevil, Hypera punctata (Gyll.), has now been identified from the alfalfa weevil, Hypera postica (Gyll.). Both conidial and resting spore stages are described.

Early in the summer of 1973, the fungus was responsible for an epizootic in populations of the alfalfa weevil throughout much of east-central Ontario. In three study plots, mortality levels in larvae and cocoons ranged from 65–90% and 42–53%, respectively. This suggests that the fungus is capable of playing a significant role in the dynamics of weevil populations.

Authors have followed Kirby in referring American specimens of Entomoscelis Chev. to the Eurasian adonidis Pallas.. One female, without label, and two male examples of adonidis from the Elbruz Mountains of northwestern Persia are before me, and they differ from American specimens, which are described below as americana n. sp., in the form of the aedeagus and in slight characters of color and sculpture. E. adonidis is said to occur from southern France and Germany to Persia and southern Siberia. There is no reason at present to believe that its distribution is continuous with that of the American form.