Twelve historically unfamiliar Ephemeroptera species described from Canada over 65 years ago were studied. Diagnostic characters are given that validate Acerpenna akataleptos (McDunnough) (Baetidae), whereas certain larval specimens of the genus Acerpenna Waltz and McCafferty cannot yet be associated with any species. Cinygmula confusa (McDunnough, 1924), syn.nov., (Heptageniidae) is shown to be a junior synonym of Cinygmula par (Eaton, 1885), and Serratella serratoides (McDunnough, 1931), syn.nov., (Ephemerellidae) is shown to be a junior synonym of Serratella molita (McDunnough, 1930). New distribution records are given for Ironodes flavipennis Traver (Heptageniidae), Cinygmula gartrelli McDunnough, Heptagenia adaequata McDunnough (Heptageniidae), and Siphlonurus autumnalis McDunnough (Siphlonuridae), including the first substantiated records for the latter three from the United States. A first larval description of S. autumnalis is provided. Ephemerella fratercula McDunnough (Ephemerellidae) is apparently rare, but its previously doubtful North Carolina record is confirmed. All larvae previously reported as Neoephemera bicolor McDunnough (Neoephemeridae) cannot be placed to any nominal species. Parameletus croesus (McDunnough) (Siphlonuridae), Plauditus rubrolateralis (McDunnough) (Baetidae), and Rhithrogena gaspeensis McDunnough (Heptageniidae) are distinctive species but are known from few records.

The name Neoligiagen.nov. is proposed for the “Oligia” semicana (Walker) species group in North America and 12 species, N. rubirena sp.nov., N. pagosa sp.nov., N. hardwicki sp.nov., N. inermis sp.nov., N. invenusta sp.nov., N. albirena sp.nov., N. lancea sp.nov., N. elephas sp.nov., N. lillooet sp.nov., N. surdirena sp.nov., N. canadensis sp.nov., and N. atlantica sp.nov. are described. Hadenella laevigata Smith is synonymized (synonymy restored) under Hadena tonsa Grote and Hadena hausta Grote is synonymized (synonymy restored) under Miana semicana Walker. Adults of all species are illustrated as well as male and female genitalia, where known.

Modern hulless wheats, Triticum aestivum L., are more susceptible to the wheat midge, Sitodiplosis mosellana (Géhin), than the hulled, wild, ancestral species. Hulless cultivars of barley, Hordeum vulgare L., are becoming more widely grown in western Canada than in the past. Hulled and hulless cultivars of two-rowed and six-rowed barleys were tested for their susceptibility to wheat midge, to determine if this midge might become a serious pest of barley and to assess which plant traits might affect host suitability. In the field, larval populations on 10 barley cultivars were much lower than on wheat. In the laboratory, when the flag leaf sheath was peeled back to expose preflowering spikes, female midges readily oviposited on spikes of barley, although less so on younger spikes. Few larvae were able to develop on barley when eggs were laid after spikes had flowered. All barleys completed flowering, or nearly so, before spikes emerged from the flag leaf sheath, with two-rowed cultivars flowering earlier than six-rowed barleys. No differences in larval densities were found between hulless and hulled barleys, and therefore, factors other than the hulled trait must account for reduced susceptibility of barley. Because barley flowers within the flag leaf sheath, its period of susceptibility to infestation is much shorter than for wheat, as evidenced by reduced infestation of earlier-flowering two-rowed cultivars compared with later-flowering six-rowed cultivars. Also, the tight closure of the leaf-like glumes that form the florets of barley probably makes access to young seeds more difficult for newly hatched larvae than is the case for wheat. At comparable crop growth stages, larval densities on all the barleys were < 10% of those on spring wheat. The introduction of hulless barley for production in Canada is unlikely to increase wheat midge damage on barley to an economic level.

The effectiveness of felt egg traps to detect oviposition by the cabbage maggot, Delia radicum (L.), was studied under field conditions for cabbage, Brassica oleracea L. var. capitata L. (Brassicaceae), and rutabaga, Brassica napus L. var. napobrassica (L.) Reichenb. (Brassicaceae), in 1994 and 1995. The numbers of eggs laid on traps were compared with the numbers deposited in the soil next to the plant. Also, the incidence of oviposition (i.e., the percentage of samples with eggs) on soil and traps was compared. A total of 5160 eggs was collected from 5208 samples, but just 16% of all samples had eggs. For cabbage, early in the 1994 season, the incidence of oviposition in soil samples was double that on traps, and the number of eggs per sample was greater also. Oviposition incidence and the number of eggs per sample during the rest of the summer were similar. In the 1995 cabbage trial, the incidence of oviposition early in the season was again higher in soil samples than on traps, and there were fewer eggs per trap than per soil sample. For rutabaga, the number of eggs was similar using both methods early in the second generation, but from mid-August there were more eggs per trap than per soil sample. The incidence of oviposition in the rutabaga trial was similar on traps and in soil through most of the experiment. In this study, felt traps did not adequately detect the timing of cabbage maggot oviposition in the critical early season.

Escape from natural enemies may favor the incorporation of a novel host plant into the diet of an herbivorous insect. This scenario has been suggested for the recent host-plant shift by the goldenrod stem galler, Eurosta solidaginis Fitch (Diptera: Tephritidae), from the ancestral host Solidago altissima L. (Compositae) to the derived host Solidago gigantea Ait. In this study, we examined the effects of predation from downy woodpeckers, Picoides pubescens L. (Aves: Picidae), and black-capped chickadees, Parus atricapillus L. (Aves: Paridae), on these two host races of insects at the western edge of their zone of sympatry. Based on a field census, bird predation was concentrated near the cover of trees where S. gigantea tends to occur; few attacks occurred in the open where S. altissima is prevalent. We conducted a field experiment to evaluate the preference of these avian predators for galls of the two host races when differences in the microgeographic distribution, size, and height of galls were controlled. In allopatric sites where only S. gigantea occurs, attacks by birds were 58% more frequent on S. gigantea than on S. altissima galls. Similar results were found for sympatric sites, although the difference in attack was only 26% and not significant. We could find no difference in the toughness of galls or the nutritional value of a larva within the gall (in terms of biomass) to explain avian preference for the S. gigantea host race; however, we found that from 1999 to 2000, the S. gigantea race offered a 27–107% higher reward rate (i.e., the probability that a gall harbored a larva of E. solidaginis) than the S. altissima race. Our studies suggest that avian predators can assess a gall’s content prior to pecking it open, preferring galls that are inhabited by both E. solidaginis larvae and the inquiline predator Mordellistena convicta Leconte (Coleoptera: Mordellidae). It is possible that birds have either learned through experience or evolved through natural selection to choose the more profitable S. gigantea galls. Finally, our results suggest that avian predators act against the maintenance of two distinct host races in the midwestern United States.

The successful flight takeoff of untethered Colorado potato beetles, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), consists of a strongly sequenced set of behaviors beginning with site location and followed by expansion of the hind wings, rising of the mesothoracic legs, air lifting, and rising of the prothoracic legs, leading to a low angle flight departure. A series of ablation experiments demonstrated that the antennae, the elytra, the mesothoracic legs, and the prothoracic legs all play a significant role in determining the percentage of successful flight takeoffs, as well as the proportion of upward versus downward liftoffs. Flight takeoff of tethered L. decemlineata is positively stimulated by head winds of increasing speeds up to speeds of slightly more than 5.5 m/s. The absence of tarsal contact does not stimulate flight takeoff in L. decemlineata, but tarsal contact interrupts flight. The flight characteristics during liftoff indicate that this species is an in-phase functionally four-winged insect, probably with the hind pair of wings leading the wing beat. Among Coleoptera, the takeoff of L. decemlineata was found to belong to the Melolontha type (classification of Schneider 1975), because the elytra are active.

Honeydew utilization by the ant Lasius niger L. (Hymenoptera: Formicidae), honeydew excretion cost for the aphid Aphis craccivora Koch, and ant protection service for aphids against the lady beetle Coccinella septempunctata L. (Coleoptera: Coccinellidae) were examined in a laboratory. The duration of honeydew utilization by ants increased with increase in aphid density. The presence of ants shortened the residence time of the lady beetle larva on a plant and reduced the proportion of aphids eaten. At a density of 5 aphids per plant, one aphid with ants excreted honeydew at a frequency two times higher than that of an aphid without ants, but not at a density of 100 aphids per plant. Therefore, a larger aphid colony may increase the benefit and decrease the cost of ant attendance.

Mate acquisition in moths typically entails long range response of males to female-produced signals, although in several species males may attract females (Birch et al. 1990; Conner 1999; Phelan 1997). Tirathaba mundella Walker attacks oil palm in Southeast Asia (Barlow 1982; Kalshoven 1981). Larvae bore into and feed inside inflorescences and fruit bunches, causing a major reduction in oil production. Observations (Y Sasaerila, unpublished data) suggested that females are attracted to signaling males. Our objectives were to (i) determine the sex emitting or responding to sexual communication signals; (ii) describe calling and courtship behaviour; and (iii) determine the diel periodicity of sexual communication.

Because Dioryctria amatella (Hulst) is a key pest in loblolly pine, Pinus taeda L. (Pinaceae), seed orchards in the southeastern United States, improved timing of insecticide applications would be valuable for its control. To time two fenvalerate (Pydrin® 2.4 EC) applications we tested four variations of a degree-day model that was developed to predicted when various proportions of D. amatella eggs would hatch during the spring generation. We compared reductions in Dioryctria spp. cone damage to unsprayed checks and a standard operational spray regime of four monthly applications of fenvalerate. In addition, we examined seeds from healthy cones to determine if sprays to control D. amatella also reduced seed damage caused by Leptoglossus corculus Say (Heteroptera: Coreidae) and Tetyra bipunctata (Herrich-Schäffer) (Heteroptera: Scutelleridae). Trials were conducted from 1984 to 1986 in two orchards in South Carolina and one in Alabama. Degree-day accumulations (threshold = 11 °C) were begun on the day when the cumulative number of male D. amatella equaled or exceeded five captured in 15 Pherocon 1C® traps baited with 100 μg of Z-11-hexadecenyl acetate. One application per year was insufficient to control D. amatella or reduced seed-bug damage. Two sprays based on D. amatella phenology significantly reduced coneworm and seed bug damage, and were as effective as four sprays applied monthly. None of the treatments reduce spring cone losses, which are primarily caused by Dioryctria merkeli Mutuura and Monroe. Several variations of the model performed well, but we suggest that the best, based on efficacy and ease of use, was when sprays were applied immediately after five males were caught (degree-day = 0) and again when the model predicted 50% of the spring generation eggs had hatched.

Bioassays and direct counts were used to assess the abundance of resting spores of the gypsy moth, Lymantria dispar (L.), fungal pathogen, Entomophaga maimaiga Humber, Shimazu and Soper in forest soils. Resting spores in soil collected in October, January, and March and held under refrigeration germinated as readily as spores collected in April, but those collected in April germinated faster. Bioassays of resting spores in soils from different sites in Connecticut were directly related to results obtained from physically counting spores in the soil, and weakly correlated with a previously developed forest-based bioassay. The number of resting spores in a site was inversely related to the number of years since the site had last been defoliated by the gypsy moth, resulting in an implied maximum viability of resting spores of about 10 years. This maximum longevity was similar to a direct measure of long-term resting-spore viability. The study implies that resting-spore load in the soil may be an important determinant of the ability of the pathogen to control the gypsy moth.