The effects of Abate, Dursban, and Methoxychlor and their diluents on black-fly larvae and on “non-target” stream invertebrates were evaluated by means of cone, rock, Surber, and drift samples. Blackfly larvae were found in many post-treatment Surber samples, although concurrent cone and rock samples often indicated that blackfly larvae were either greatly reduced in numbers or eradicated from the streams. The insecticide diluents (H.A.N, and fuel oil) caused detachment of blackfly larvae from cones, but less than that obtained when insecticide was added.

The heavy post-treatment drift of “non-target” invertebrates in treated streams is indicative of a considerable disturbance to the aquatic invertebrate community. However, post-treatment samples indicated that the “non-target” organisms studied were not eradicated from the streams.

There were several indications that the catch of invertebrate drift was altered by pools, which possibly exerted a delaying action on drifters in the treated streams. Most of the drifting invertebrates found in post-treatment drift nets were dead.

Lophyroplectus luteator (Thunb.), a European ichneumonid, has been established as a parasite of Neodiprion sertifer (Geoff.) from a release made in 1962, and has dispersed approximately 12 miles (19.3 km) in the 7 years following introduction. A second, smaller release in the same year failed. In a third release, made in 1964, recoveries were made every year until sampling was stopped in 1971, but dispersal has only been approximately 2 miles (3.2 km).

The emergence and adult activity of Aedes (Ochlerotatus) impiger and A. (O.) nigripes during 1962–66 at Hazen Camp (81°49′ N., 71°18′ W.), Ellesmere Island, N.W.T., are described.

The greater part of seasonal emergence (assayed by emergence traps) took place from shallow ponds during a period of 7–10 days, usually in early July. Emergence of A. impiger began about 3 days earlier than that of A. nigripes, and peak emergence of the two species was separated by about 4 days; males of both species normally emerged 1 or 2 days before the females. From each pond 80% of annual emergence usually occurred within 3 or 4 days. Pond-to-pond differences were correlated closely with water temperature, but delayed emergence occurred at the end of the emergence period in temporary ponds, as the ponds became dry. Year-to-year temperature differences altered both the seasonal position and the duration of emergence in a given pond by up to 10 days.

The flight activity of adults (assayed by a Visual Attraction Trap and a Malaise Trap) was greatest shortly after the period of greatest emergence, but adults, especially females, were caught for more than a month after emergence had ended. Biting by females continued throughout this period, but swarming of males was more abbreviated, especially in A. impiger. The number of adults trapped fluctuated from day to day according to weather: flight was inhibited when maximum screen air temperatures were below about 5 °C. The interval required for ovarian maturation was about 9 days in both species, and some females completed at least three gonotrophic cycles. The successive cycles were detected in the population by analysis of sweep-net catches, the proportion of gravid females caught in the traps being affected considerably by weather. Successive gonotrophic cycles were well synchronized, like emergence, in A. nigripes; retention of eggs apparently obscured such synchrony in A. impiger.

Feeding on nectar (of the flower Dryas integrifolia) was apparently needed by both sexes to maintain activity, at least upon emergence.

Year-to-year differences in the numbers of adults emerging were correlated with the amount of flight, and hence reproductive activity, permitted by weather the previous year.

These findings are summarized graphically (Fig. 21). Critical comments are made on the usefulness of some of the sampling methods employed. Some characteristic biological features of arctic mosquitoes, leading to prompt emergence in spring and permitting subsequent reproductive activity despite the low temperatures and variable weather of the summer, are discussed.

The results of systematically-conducted, mid- to late-season observations and experiments on large populations of apple maggot flies, Rhagoletis pomonella (Walsh), in apple and sour cherry trees revealed the following sequences in courtship behavior. When environmental conditions are favorable, sexually mature males and females fly to the host fruit, the site of assembly for mating and the site of oviposition. Either sex may initiate the flight which takes it to the particular fruit occupied by a member of the opposite sex. Such flights by males are often in response to the visual stimulus of a female (or male) moving about on a fruit, while such flights by females seem to be primarily in response to the fruit as a potential oviposition site. Once on the same fruit, a male and a female locate one another apparently solely through vision, particularly movement. They walk to within 1–3 cm of one another, but there is no tactile contact until such time as the male attempts copulation by jumping onto the back of the female from this distance.

The position from which the copulatory jump is made is variable. Sometimes it is made from a face to face position, with one or both flies having waved its pictured wings at the other. Occasionally it is made from the side or from a flight from a nearby fruit directly onto a female’s abdomen. Most often however, it is made when a male is stimulated by the forward movement of a female, approaches her from the rear, and jumps onto her abdomen from the rear without the female having seen the male. Most copulation attempts, and especially most successful attempts, are initiated while the female is engaged in some phase of oviposition behavior. Males attempt copulation with other males just as often as with females, strongly suggesting that at least up until the time of tactile contact, males are unable to distinguish between the sexes. The fact that a number of male and female apple maggot flies was observed in copula with R. fausta flies in sour cherry trees suggests that neither sex may be able to discriminate too well between members of its own species and members of other species whose wing and body patterns are similar in appearance However males were usually, although not always, able to distinguish stable flies from apple maggot flies prior to tactile contact.

We discuss the known and possible roles of various visual, chemical acoustical, and physical-tactile cues involved in the courtship behavior and suggest that the most important factor insuring reproductive isolation in apple maggot flies at the pre-copulatory stage may be the selection of the proper host plant for oviposition and hence for assembly for mating.

Competitiveness of laboratory-reared Lucilia cuprina (Wied.) has been examined under field conditions. The separate release of males and females each marked genetically and with fluorescent dust permitted estimates of dispersal, survival and mating competitiveness for both sexes. The ability of males to seek mates and introduce marker genes into a field population did not appear to be impaired as a result of several years of laboratory colonization. Released females were readily inseminated though suitable conditions did not exist for adequate assessment of their ability to produce offspring.

Overwintering stages of the European red mite, Panonychus ulmi (Koch), and the McDaniel spider mite, Tetranychus mcdanieli McGregor, on harvested apples were destroyed with ethylene dibromide using a dosage of 6 mg/l. for 4 h at 24 °C. Some control was achieved at lower temperatures but the dosage had to be increased accordingly. No injury of the fruit occurred. Taste tests showed that flavour of the apples was not adversely affected even after treatment with 10 mg/l. for 4 h.

Two of three species of the genus Rhantus studied were found to produce sounds while in water. Sound production by both sexes of R. gutticollis and R. binotatus occurs in a behavioral context of emigration, while R. atricolor does not produce waterborne sounds. Elevated temperature, absence of suitable bottom substrate, and high densities were effective stimuli for sound production by’ the two acoustically active species. The sounds were analyzed and a mechanism previously described as being involved in preflight warm-up of the thoracic musculature was found responsible for sound production in water. Possible functions of acoustical behavior are discussed, and new information on some aspects of the habitat ecology and general behavior of adults of the three species is provided.

Males of the fruittree leafroller, Archips argyrospilus (Walker), were attracted to traps containing either virgin females or cis-11-tetradecenyl acetate (cis-11-TDA) combined with dodecyl acetate. In two of three field tests traps containing virgin females captured significantly more males than the synthetic lure. Trap captures indicated that the ratio of cis-11-TDA to dodecyl acetate influenced the attractiveness of the mixture, but that increased amounts had no significant effect.

In answer to Mansingh’s criticism the value of Müller’s system of dormancies is emphasized. It gives especially a clear differentiation between the obligatory dormancy called parapause, which is under the control of only one environmental factor, and the facultative eudiapause, where different factors are working respectively as inducing and terminating. The carabid beetles are an example that illustrates that no narrow correlation can be found between the distribution of dormancy types and the climatic zones on the earth they live in.