Larvae of bertha armyworm, Mamestra configurata Walk., collected in 1972–75 on rapeseed in the prairie provinces of Canada (predominantly in Manitoba), were killed by one virus, one fungus, one microsporidium, seven insect parasites, and by other factors. Mortality from disease was about 24% in 1972 when bertha armyworm was abundant, but much lower in succeeding years after the host’s population density declined. The most important hymenopterous parasite, Banchus fiavescens Cress., was relatively rare in 1972 but subsequently killed over 40% of the host larvae each year. A tachinid, Athrycia cinerea (Coq.), killed over 20% of the mature bertha armyworms in each generation. Each of the other five parasite species was associated infrequently with M. configurata. Details of the biology of each pathogen and parasite are presented. About 12% of the mature host larvae died because they failed to empty the gut, with subsequent penetration of the gut wall by bacteria, or because they did not form a morphologically-sound pupa. Pupae of M. configurata died in the soil following penetration of the gut wall by bacteria, as a result of soil cultivation, and from low temperatures in winter. No pathogens or parasites were recorded in field-collected pupae, though an ichneumonid, Ichneumon canadensis Cress., parasitized pupae in a field cage and may occasionally do so in natural conditions. No pathogens or parasites of bertha armyworm eggs were recorded. A preliminary survival model for bertha armyworm, based on estimates of mortality from various causes identified in this study, is presented. The possibility of preventing or reducing future oubreaks of M. configurata by colonizing additional parasite or pathogen species in the prairie provinces is discussed.

The effect of delayed mating on the reproductive biology of females of the Oriental fruit moth, Grapholita molesta (Busck), was studied in the laboratory. Expected reproduction, defined as t-th day survival rate × percent successful mating × total viable eggs, was reduced by 13, 36, and 74%, respectively, after a 2-, 5-, and 10-d delay in pairing with a male compared with females that were paired with a male on their day of emergence. Female fertility (percentage of females laying fertile eggs), fecundity (total number of eggs laid), egg fertility (percentage of eggs developing to black head stage), and egg hatch (percentage of eggs hatching) were reduced by delays in mating. The pre-oviposition period of females mated within 24 h of emergence was longer than that of females mated 2, 5, or 10 d after emergence. The duration of the oviposition period declined with delays in mating. Female longevity increased with delays in mating and was greatest in virgin females. The number of eggs laid per day was similar in females paired with a male 2, 5, and 10 d after their emergence. Commencing 2 d after pairing, females paired on their day of emergence exhibited a daily oviposition rate similar to that of females paired 2–10 d after emergence. These observations suggest that the successful control of the Oriental fruit moth using sex-pheromone-mediated orientation disruption (mating disruption) is more likely accomplished by preventing mating than by delaying mating.

The genetic make-up of representative populations of five Choristoneura species was compared using starch gel electrophoresis. Species included C. occidentalis Freeman from Idaho, C. biennis Freeman from British Columbia, C. retiniana (Walsingham) (= C. viridis Freeman) from Oregon, C. lambertiana ponderosana Obraztsov from Colorado, and C. fumiferana (Clemens) from Maine. When variation at individual gene loci was examined, intraspecific variation was often as great, and sometimes greater, than interspecific variation and few significant differences were noted among the species. The highest levels of overall genetic similarity occurred among C. occidentalis, C. biennis, and C. retiniana. Relatively greater genetic distances were found between this group and C. lambertiana and C. fumiferana. C. fumiferana was most distantly related to all other groups. Genetic identity values fell within the range more commonly associated with conspecific populations rather than with separate species.

Experiments were conducted using balsam fir twigs treated with Bacillus thuringiensis Berliner to examine the influence of temperature and exposure time on mortality of spruce budworm, Choristoneura fumiferana Clemens. Twigs were sprayed with a commercial formulation (8.4 BIU/L) using droplets of 40–70 μm diameter at densities, ranging from 0.5 to 5.5 droplets per needle. Temperature affected progression but not the level of cumulative mortality during 14 days of feeding on sprayed foliage. The LT50 decreased from 12–17 days at 13°C to 2–4 days at 25°C, depending on droplet density. Temperature between 13 and 25°C had a limited effect on dose acquisition because 40–60% of the larvae were able to acquire a lethal dose within 1 day of feeding on foliage with 0.5–1.5 droplets per needle, regardless of temperature. Under these conditions dose acquisition was not limited by temperature-dependent consumption of foliage, but rather by feeding inhibition associated with the dose initially ingested. This also limited the influence of exposure time; a 7- or 14-fold increase in exposure time increased larval mortality at most by 25%. Implications of these findings for improving efficacy of B. thuringiensis in forestry applications are discussed.

It has been suggested (Wright, 1958) that attractants or repellents for insects which normally fly to their destination should be tested against insects that are in flight during the tests. Moreover, the conditions of the flight should be as nearly natural as possible. This requires that the observation chamber should be large (to minimize wall effects), the illumination should be controllable, and the air movement and the odorous or other signals should be presented in a natural way. Finally, the movements of the insects should be recorded in three dimensions, and in as much detail as possible.

Observations on the life cycle and habits of Enoclerus lecontei were made in the laboratory and field. The eggs passed through distinctive color changes during their development; these color changes were used to determine their age. The three larval instars were separated on the basis of head capsule width. Larval size varied according to the amount of food consumed. All larvae were orange-red in color, except the third instar which altered to purple 4 to 6 days after moulting. The duration of the respective stadia were first, 8 to 15 days; second, 5 to 8 days; third, 19 to 35 days. At least one mature prey-larva was necessary for development in each instar but up to seven were consumed. The third instar fed for only 4 to 11 days, the remaining time was spent in a highly mobile, non-feeding stage. The pupal stage lasted 9 to 11 days. Adults lived 36 to 114 days and consumed from 44 to 158 bark beetle adults. The sex ratio was 1:1. The mating habits, oviposition behavior and feeding behavior are described.

Laboratory studies showed that the emergence of Rhagoletis pomonella is affected by the relative humidity of the environment. When pupae were incubated at 77° F. and relative humidities of 20, 40, 60, 80 and 100 the percentages of emergence were 0, 0, 4, 81 and 70 respectively.

The food intake of fourth, fifth, and sixth instar spruce budworm, Choristoneura fumiferana Clemens, was investigated by feeding larvae for 24 h artificial diet incorporating amaranth dye. Amaranth was selected because it followed Beer's law over a wide concentration range, mixed well with the meridic diet, could be extracted in ice-cold water, was not absorbed by larval tissue, had minimal feeding deterrence as well as marginal adverse chronic effects on the larvae, and finally had negligible effect on ingestion rate over a 24 h period. The results indicated that 6th instars consumed 20 times and 5th instars 3 times as much as 4th instars, but when compared on a body weight basis the ingestion rate was similar in all three instars. Temperature and photoperiod influenced the rate of food intake. The application of these findings in assessing defoliation to the forests as well as estimating dosage of pesticides for control of this species are discussed.

Insect-detection traps baited with the synthetic aggregation pheromones of the rusty grain beetle, Cryptolestes ferrugineus (Stephens), were inserted into grain stored in primary elevator annex bins and in farm bins, or suspended in partly full or empty bins and outside under the eaves of bins. The mixture of the synthetic pheromones 4,8-dimethyl-E,E-4,8-decadienolide (ferrulactone I) and (Z)-3-dodecen-11-olide (ferrulactone II) was released from hollow polyester fibers (0.203 mm ID) positioned in the interior of the insect-detection trap. In annex bins, the number of beetles found in baited traps after 1 week ranged from 0 to 7300. In these bins, more beetles were found in traps at a depth of 30–60 cm than at 150–250 cm, and in traps with 2 fibers containing pheromone rather than with 1 fiber. In farm bins, baited and unbaited traps were relatively ineffective at grain temperatures below 14 °C. More beetles were found in baited than in unbaited traps in farm bins but the numbers were small and the differences were not significant. Few beetles were found in traps suspended in partly full or empty farm bins and none in traps suspended outside under the eaves.

Effective management of the interactions within the mite community is critical to biological control of economically damaging phytophagous mites such as Panonychus ulmi Koch (Tetranychidae) (Clements and Harmsen 1990). Although much is known about the potential role of phytoseiid mites in controlling P. ulmi (Dover et al. 1979), mites from at least seven other families may be present in apple orchards (Thistlewood 1991). Stigmaeid mites are predators which may play a beneficial role in biological control in conjunction with phytoseiids (Clements and Harmsen 1992). Eriophyid mites are phytophagous but seldom cause economic damage, and may compete with tetranychids and provide alternative food for predators of tetranychids (Croft and Hoying 1977).

Honey bees, Apis mellifera (L.) (Hymenoptera: Apidae), are parasitized by the microsporidians Nosema apis (Zander) and Nosema ceranae (Fries). Molecular techniques are commonly used to differentiate between these parasites because light microscopy is inadequate. Our objectives were to (i) adapt the previously published duplex polymerase chain reaction (PCR) targeting the 16S rRNA gene of N. apis (321APIS-FOR, 321APIS-REV) and N. ceranae (218MITOC-FOR, 218MITOC-REV) using qualitative real-time PCR assay with SYBR® Green I dye (R-T PCR) and DNA melting-curve analysis, and (ii) determine whether the two Nosema species can be detected simultaneously in honey bees. Total spore counts and purified total genomic DNA were obtained from 37 bee samples (19 individual workers and 18 pooled samples of 15 workers) collected in Nova Scotia, Prince Edward Island, and Newfoundland, Canada. Overall, the prevalence of Nosema species was 86.5% (32/37 samples of bee DNA), based on conventional PCR and the optimized R-T PCR assay. The melting-curve analysis showed three groups of curve profiles that could determine the prevalence of N. apis, N. ceranae, and co-infection (21.9%, 56.2%, and 21.9%, respectively). The duplex R-T PCR assay was efficient, specific, and more sensitive than duplex conventional PCR because co-infection was identified in 5.4% (n = 2) more samples. Sequencing of R-T PCR products confirmed the results of the melting-curve analysis. Duplex R-T PCR with melting-curve analysis is a sensitive and rapid method of detecting N. apis, N. ceranae, and co-infection in honey bees.

Pitfall trapping revealed that the European fire ant, Myrmica rubra (Linnaeus) (Hymenoptera: Formicidae), represents an unusual example of a temperate invasive ant species. In British Columbia, Canada, M. rubra populations are associated with a decreased incidence and abundance of other ant species in three different plant communities when compared with M. rubra-free control areas. M. rubra represented more than 99.99% of the total ant fauna caught in the infested areas, and the numbers of M. rubra captured in the plant communities ranged from over 10 times to over 1300 times the total number of all ants collected in corresponding M. rubra-free areas. Total numbers of some taxa of insects and non-insect arthropods, including those likely to be competitors or prey of M. rubra, were reduced where the invasive species was present. Biodiversity indexes for the overall suite of captured arthropod species were lower where M. rubra was present in all three plant communities but most of this decrease can be attributed to the difference in the ant fauna.

The first matings of males resulted in the transfer of large spermatophores, while subsequent matings resulted in smaller and eventually no spermatophore. The transfer of a spermatophore was not required to produce a normal number of fertile eggs. Some young males inseminated two females within 24 hours and regardless of whether or not a spermatophore was formed the number of resulting progeny was normal. Thus males were found to be capable of inseminating more females than the yield of spermatophores obtained by dissecting females indicated.

Virgin females increased in attractiveness with age at least until their fifth day.

Larvae of species representing 12 of the 13 genera of the superfamily Lebertioidea from North America are described, including members of the genera Bandakiopsis, Utaxatax, Estelloxus, and Testudacarus for the first time. Larvae of species of Sperchon, Sperchonopsis, Teutonia, Bandakia, Lebertia, Oxus, Frontipoda, and Torrenticola are also described to provide complete comparative data for the genera of the superfamily. A key to the families and genera of Lebertioidea, and preliminary diagnoses for the superfamily, families, and genera are provided based upon larval characters. Information on host associations is reviewed for each taxon. Observations on morphology and host associations of these larvae provide the basis for an original, though provisional, outline of phylogeny of Lebertioidea, and a review of the higher classification of the superfamily.

Sampling to obtain valid estimates of the degree of parasitism in natural populations of insects presents a difficult problem to the quantitative-minded investigator. The method used must adhere to the principles of random sampling, yet it must be truly representative with respect to the occurrence of the parasite in its sampling universe, the host insect, in both time and space.

The endemic New World eucheiloid complex is distinguished from the other complexes (thyreopteroid, eurycoleoid, somotrichoid, and pericaloid) of pericaline Lebiini by securiform labial palpomere 3, serrate-setose margins of the pronotum, and flattened stylomere 2 of the ovipositor. The geographical range of eucheiloids extends from northern Argentina to southernmost United States (Brownsville, Texas). All taxa are believed to be arboreal. A key distinguishes among the three genera and 16 species, and each taxon is characterized in terms of structural features, habitat, and geographical distribution. The genera are: Hansus, new genus (generitype—H. reichardti, new species); Inna Putzeys (generitype—Inna punctata Putzeys = Polystichus boyeri (Solier)); and Eucheila Dejean (generitype—Euchyla flavilabris (Dejean)). Seven new species and one new subspecies are described: Hansus reichardti (type locality—Guyana, EssequiboR.. Morrabali Ck.); Inna palpalis, I. atrata arbor, and I. inpa (type locality—Brazil, Amazonas, near Manaus); I. purpurea (type locality—Brazil, Amazonas, 60 km n. Manaus); I. splendens (type locality—Venezuela, Aragua, Rancho Grande); Eucheila adisi (type locality—Brazil, Amazonas, 60 km n. Manaus); and E. cordova (type locality—México, Veracruz, Cordova). The following new synonymies of specific names are proposed (valid names listed first): Inna costulata Chaudoir, 1872 = I. granulata Chaudoir, 1872; Inna boyeri (Solier, 1835) = I. punctata Putzeys, 1863, and I. texana Schaeffer, 1910. A reconstructed phylogeny of the eucheiloids, based on analysis of 60 character states included in 33 characters, shows that Hansus is sister group of the ancestral stock of Inna + Eucheila. Evolutionary modifications have affected principally body size, head and mouthparts (feeding and associated adaptations), reproductive structures, and features of the body surface thought to be associated with avoidance of predators (concealment and flash coloration). Diversification may also have involved differentiation by habitat (type of forest occupied). The principal theater of evolution has been tropical South America, with incursions both southward and northward. Middle America has been invaded by five lineages, probably during Cenozoic time, from Middle Tertiary to the Quaternary. Of these lineages, three are represented in Middle America by endemic species: E. cordova, I. planipennis Bates, and I. nevermanni Liebke. Two lineages are represented by species whose ranges extend northward from South America: I. costulata Chaudoir and I. boyeri (Solier).

The spatial distribution of egg clusters and cocoons of Neodiprion swainei and N. sertifer is described, and methods are developed for estimating the density of different stages on the same numerical basis.

Egg-cluster density varies directly with height in the tree, branch length, and tree size, evidently due to the females’ preference for illuminated sites. The overdispersion of egg-cluster counts reflects the heterogeneity of distribution of suitable oviposition sites rather than an inherent aggregative behaviour of parent females. Cocoon density within stands is not strongly related to the distance from the nearest tree, due to the wide dispersal of cocoon-spinning larvae. Some of the overdispersion of cocoon counts is due to differences in cocoon density between sections of a stand. Cocoons of males are more highly aggregated than those of females, and cocoons attacked by predators are more highly aggregated than ones not attacked.

The sampling unit selected for each life-history stage is one that permits density estimates of desired precision at minimum cost. In some stands, egg density can be estimated at minimum cost by direct counts per quadrat, in most stands, however, the whole tree is the most economical unit, despite the fact that per-tree density must be converted to absolute density in order to express all stages on a common basis. Sampling error can be reduced by stratification according to tree size. Gradients in cocoon density are seldom steep enough to permit stratification, but the cost of sampling can be minimized by adjusting unit size. Optimal unit size varies inversely with cocoon density and degree of aggregation, and is affected by soil type and the method used to extract cocoons.

The role of spatial distribution and sampling programs in studies of population dynamics is discussed.

Descriptions are presented of larval instars of three species of the colymbetine tribe Matini Zimmermann (Coleoptera: Dytiscidae), Batrachomatus daemeli (Sharp), Matus bicarinatus (Say), and Allomatus nannup Watts, including a chaetotaxic and porotaxic analysis of the cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi. A parsimony analysis based on 32 informative larval characteristics was conducted with the computer program NONA. Members of the Matini are postulated to share a monophyletic origin based on (i) seta TR2 articulated anteroventroproximally on the trochanter; (ii) seta TR5 elongate on the metatrochanter; (iii) seta TA1 elongate and inserted proximally on the tarsus; (iv) antenomere III with a hole-like ventroapical spinula; (v) prementum with the primary setae LA2, LA3, LA4, LA5, and LA8 spine-like and elongate; (vi) presence of secondary setae on the cephalic appendages; and (vii) presence of additional primary setae on the last abdominal segment. A clade Matini + Colymbetini is postulated based on (i) metafemoral seta FE5; (ii) metafemoral seta FE6; (iii) seta TI6 on tibia, all elongate and hair-like; (iv) one-segmented urogomphus; (v) presence of an occipital suture in first instar; (vi) galea elongate; (vii) presence of natatory setae on legs; and (viii) presence of secondary setae on the urogomphus.

The development and survival of mountain pine beetles axenically reared on standardized diet at 8 constant temperatures (10°–35 °C) were observed. At 32 °and 35 °C, 22 and 18% of the eggs hatched and all larvae died within 10 d of hatching. At the lower temperatures, 60–70% of the eggs hatched. The highest survival for all developmental stages was at 24 °C. At 10° and 15 °C development of all beetles reared in bolts of lodgepole pine or on axenic diet stopped when larvae were fully developed, whereas at 24 °and 27 °C all of the beetles developed normally to the adult stage. Larvae that had stopped developing during rearing at 15 °C resumed development after being transferred to 24 °C, indicating that pupation was limited by temperature. Although mean development times to the larval, pupal, and adult stages all decreased with increasing incubation temperature, heat-unit requirements above a base temperature of 5.6 °C were lowest for individuals reared at 27 °and 24 °C for all developmental stages. At these temperatures, an estimated average of 673 and 674 degree-days above 5.6 °C were required for development from egg to the tanned (dark) adult stage, respectively. The average widths of the prothorax and the sex ratios of axenic beetles were within published ranges. Mean development times and heat-unit requirements at constant temperatures for development to various life stages agreed well with published field and laboratory studies from western Canada.