Based on data collected at seven constant temperatures, a temperature- and age-dependent model for reproductive development and oviposition by Diabrotica barberi Smith and Lawrence was developed. The model couples temperature-dependent rate and temperature-independent distribution models to represent the observed variability in developmental times for pre-reproductive, reproductive, and post-reproductive females. Using a cohort approach to maintain a physiological age structure, development was coupled with a temperature- and age-dependent model of oviposition. The model was validated at one constant-temperature and three variable-temperature regimes in the laboratory. The time spent in the pre-reproductive stage was slightly underestimated by the model, but the development of mature females and both the timing and magnitude of oviposition under fluctuating-temperature regimes were accurately predicted. The model was relatively insensitive to errors in estimation of the rate of development in the pre-reproductive stage but sensitive to errors in estimation of developmental rate of the reproductive stage and fecundity. Errors in input temperatures were found to be very important, stressing the need for accurately measuring temperature, The major driving variable. The model should be a valuable aid toward understanding oviposition by D. barberi in the field.

Body size and mass variation of queen bumble bees (Bombus Latr. spp.) were analyzed in relationship to hibernation survival and optimal body size. Body mass and size (measured by radial cell length) were significantly correlated in six of eight species. Also, spring queens of B. occidentalis Greene were, on average, significantly larger yet lighter than young fall queens. These observations were consistent with weight loss known to occur during hibernation coupled with greater mortality of small queens over the winter. Thus large queens may be at an advantage for this and other reasons (e.g. foraging efficiency, usurpation). However, an optimality model showed that an intermediate body size was optimal if the reproductive success of a colony (foundress queen and workers) was considered. The assumptions were that fitness did not increase linearly with body size but was a convex function, and that colonies only had a fixed amount of energy to invest in reproductive offspring leading to a trade-off between size and number.

Oviposition rate (eggs per ♀-degree-day) and fecundity (total number of eggs per ♀) were measured in two populations of Melanoplus sanguinipes (F.) under natural conditions during two seasons (1984, 1985). Differences in fecundity between the two seasons were indirectly associated with differences in time of hatching. In 1985, females hatched earlier and had shorter preoviposition periods, greater longevities, and higher oviposition rates; consequently, fecundity averaged about three-fold greater than in 1984. Longevity appeared to be the most important single determinant of fecundity. Maximum fecundity was 73.2 eggs (equivalent to four pods) and mean fecundity ranged between 10.1 and 28.9 eggs per female.

A combination of published techniques provided point estimates of life history parameters for two natural field populations of Melanoplus sanguinipes (F.) in crested wheatgrass pastures. Stage-specific survival rates averaged 0.4798, 0.2261, 0.7628, and 0.6903 for egg, instars I–III combined, instar IV, and instar V, respectively. Daily survival rates of adults averaged 0.9702, but were slightly lower for females than for males. Estimated duration of nymphal instars averaged 8.4 days, the adult preoviposition period averaged 13.3 days, and adult longevity averaged 26.7 and 36.3 days in the two populations. Oviposition rates were estimated for up to four successive ovipositions, and net replacement rates of populations also were estimated. Neither population replaced itself, indicating that potential capacities for increase were not approached under conditions of these studies.

A field trial was conducted to evaluate a spunbonded polyester row cover (Reemay) as a means of protecting cauliflower plants from insect pests. Total yield variables (curd weight, size, and color) did not differ significantly between plants under the row covers and those treated with insecticides, although plants under the row covers did produce a greater yield at an early harvest date. Plants in control plots failed to produce any marketable heads, owing to attack by cabbage maggots, Delia radicum (L.). Row covers may be a useful alternative to insecticides for pest control via physical exclusion of the key pest(s) from the crop plant.

Three benzoylphenylurea insecticides, diflubenzuron, triflumuron, and teflubenzuron, were toxic when applied to eggs of Phyllonorycter blancardella (Fabr.) 0–2 and 4–6 days post-oviposition. Most treated eggs hatched but larvae died in the early instars. High larval mortalities also occurred when treatments were applied to foliage prior to oviposition. Treatments applied to larvae, especially older larvae, were less toxic than those applied to eggs. In the field, control was similar whether insecticides were applied during egg deposition, first hatch of eggs, or against early-instar larvae. Applications during egg deposition are suggested as optimal for control. Control of spotted tentiform leafminer with insect growth regulators was equivalent to that obtained with deltamethrin or methomyl.

Residues of diflubenzuron and triflumuron, applied pre-bloom, persisted until leaf drop 19 weeks later. Residues of teflubenzuron persisted for 9 weeks. Populations of spotted tentiform leafminer were suppressed throughout the season and residues of all insect growth regulators except teflubenzuron applied in May were toxic to larvae into October.

The encyrtid wasp Epidinocarsis lopezi (De Santis) has been introduced into Africa as a biological control agent against the cassava mealybug Phenacoccus manihoti Matile-Ferrero. This host has a defense reaction against the immature parasitoid that involves encapsulation and melanization. Under laboratory conditions, 37.5% of once-stung cassava mealybugs had been parasitized, as indicated by eggs and larvae of the parasitoid in dissected hosts. Of these parasitized cassava mealybugs, 89.6% contained melanized particles (egg, partially melanized larva, internal host tissues, exoskeleton wound scars). Some of the parasitoid larvae were only partially melanized, and either freed themselves from the melanized capsule or else shed it at the next molt. By the 3rd day of their development only 12.5% were completely melanized. In cassava mealybugs with melanized host tissue but no living parasitoid, the survival of the host was not affected by the melanization. The mealybug itself sometimes shed black particles at the next molt and these were found attached to the cast skins. When superparasitized in the laboratory, 68.6% of twice-stung cassava mealybugs contained parasitoids. Mummies collected from a field experiment showed that melanization rates of mummies increased with increasing parasitization rates. Thus, melanization in the cassava mealybug was commonly triggered when E. lopezi oviposited, but this defense reaction was mostly ineffective, permitting the introduced parasitoid to be a successful biological control agent in Africa against the cassava mealybug, a major pest on this important food crop.

The winter moth Operophtera brumata (L.) is a serious introduced pest of apple trees in Nova Scotia. It spread westward through orchards of the Annapolis Valley in the 1950’s and to other deciduous trees throughout Nova Scotia later. The parasites Cyzenis albicans (Fall.) and Agrypon flaveolatum (Grav.) were liberated during 1961 in Nova Scotia and gradually spread throughout the winter moth population. Population dynamics studies were conducted in insecticide-free orchards and corroborated with observations in neglected unsprayed apple trees over a wide area. The winter moth population reached a balanced level in unsprayed orchards at varying densities below the limits of its food supply, but well above an acceptable level for commercial apple production. In young orchards, where trees cover a small percentage of the ground, natural dispersal of larvae appeared to be a suppressing factor. In mature orchards mortality was density dependent during the prepupal to adult stage; mortality was partly due to parasitism and predation but also to other factors.

The distribution of spruce beetle attacks and length of associated egg galleries were investigated on 21 spruce stumps over a 4-year period in central British Columbia. Attack density formed a distinct vertical gradient which peaked near the duff line at about one-third stump height above the mineral soil. The proportion of attacks on the stumps that were located below the duff was linearly related to the ratio of stump height below duff and total stump height above mineral soil. Attack density was significantly higher below the duff than above. A three-parameter exponential function gave satisfactory fit to the attack density gradient on normalized stump height. A discrete-step theoretical model was also developed based on assumptions regarding beetle behavior during landing and imitation of the egg gallery and the physical characteristics of the host. This model gave an excellent fit to the attack density gradient as an average process over all stumps. Average egg gallery length was a curvilinear function of attack density with maximum average egg gallery length occurring at about 0.33 attacks per 100 cm2.

The larvae of all known species of Acroceridae are internal parasites of spiders (Araneae) and recently (Sferra 1986), first-instar larvae have been described from mites (Acari). The eggs usually are laid in close proximity to their hosts, and the first-instar larvae (planidia) wait for, or actively seek, a host. Once a host is found, the larvae burrow through the spider's integument and attach to the book lungs where they remain in diapause for several months. The consecutive larval instars occur rapidly, during which time the larva consumes most of the liquid contents of the host. The larvae emerge posteriorly from the host, attach to the spider silk for pupation, and adults emerge in 7–10 days. Acrocerid biology was most recently reviewed by Schlinger (1969, 1981).