In nature, competing species often achieve coexistence through niche differentiation. We examined this phenomenon for Pachycrepoideus vindemmiae and Spalangia endius (Hymenoptera: Pteromalidae), two species of pupal parasitoids that are considered biological control agents of house fly, Musca domestica (Diptera: Muscidae). We examined the ability of each species, alone and in combination, to locate host pupae buried at different depths (0, 1, 2, 4, and 6 cm) in three types of substrate (sand, dry wheat bran, and spent fly diet). We then evaluated the competitiveness of each species by allowing first one species, then the other species, to parasitise host individuals within time periods ranging from less than 2 hours to 96 hours of each other. Spalangia endius exhibited greater ability than did P. vindemmiae to locate host pupae buried at depths below one centimetre. Conversely, P. vindemmiae exhibited a greater competitive ability, being more likely to emerge from pupae co-parasitised by S. endius, regardless of oviposition interval or sequence. Our findings suggest that these two parasitoid species coexist through niche differentiation. Our findings also indicate that to increase the effectiveness of biological control, the environmental conditions and risk of interspecific competition should be considered when selecting parasitoid species for release.

Field-acclimated Drosophila suzukii (Diptera: Drosophilidae) from the Saguenay–Lac-Saint-Jean region, Québec, Canada, were examined over two years for winter survival, under the hypothesis that flies select protected overwintering microhabitats. In 2016–2017, flies trapped alive in the field or emerged from infested fruits were submitted to four winter regimes of either constant or daily fluctuating temperatures of 5 °C (2–8 °C) or 10 °C (7–13 °C). In 2017–2018, two fluctuating regimes averaging either 1 °C (–2 to 4 °C) or 3 °C (0–6 °C) were tested. Survival was modelled using Cox proportional hazard models testing probability that mortality risk varies with cold winter regime, fly sex, and fly provenance. Hazard ratios were about 1.7 times higher for males than for females. Models indicate that flies in constant and fluctuating 10 °C, in constant 5 °C, or in fluctuating 1 °C with daily exposure to –2 °C would not survive a six-month winter. Female survival extended to the next summer in fluctuating regimes averaging 5 °C or 3 °C. Estimates of 0.95 quantile survival (5%) indicate that overwintering D. suzukii experiencing such cold temperature regimes during winter, with no prolonged sub-zero temperatures, could survive until July of the following year, which is likely at the high population densities observed.

Understanding the medical and economic impacts of mosquitoes (Diptera: Culicidae) begins with knowing their natural history and distribution, including their association with habitat types, particularly those in which human activity is high. The effects of habitat on shaping the community structure of mosquitoes were studied across periurban habitats on the island of Montréal, Québec, Canada in 2014 and 2015. Mosquitoes were collected from 20 fixed sampling locations in suburban backyards, fields, and forests, using CO2-baited light-emitting diode encephalitis vector survey traps. A total of 184 607 mosquitoes were collected, representing eight genera and 35 species. Suburban, field, and forest sites had different communities of mosquitoes, but differences were not apparent among sites within similar habitat types in nonmetric multidimensional scaling ordinations and permutational multivariate analysis of variance. In both years, the greatest abundance of mosquitoes was collected from field habitat, and the highest species richness, from forests. Suburban sites consistently generated the lowest abundance and diversity. Nearly 75% of the total individuals collected were from three species: Aedes vexans (Meigen), 39%; Coquillettidia perturbans (Walker), 18%; and Aedes canadensis (Theobald), 16%. This research shows that diverse communities of mosquitoes can be found in forests, fields, and backyards, yet the communities between forests differ from more open habitats. Our community analysis reveals that medically important species (e.g., Culex sp.) are more commonly encountered in suburban backyards, yet overall mosquito nuisance potential is greater in forest and field habitats. This information highlights important patterns of mosquito abundance and species occurrence, vital for the development of management programmes.

We evaluated the host suitability and related traits of Trichoplusia ni Hübner (Lepidoptera: Noctuidae) and Chrysodeixis chalcites Esper (Lepidoptera: Noctuidae), which is nonnative in North America, for the native parasitoids Campoletis sonorensis Cameron (Hymenoptera: Ichneumonidae) and Copidosoma floridanum Ashmead (Hymenoptera: Encyrtidae), and the nonnative parasitoid Cotesia vanessae Reinhard (Hymenoptera: Braconidae). For the larval parasitoid C. sonorensis and C. vanessae trials, three-day-old larvae of both hosts were used, whereas one-day-old eggs of both hosts were used for the egg–larval parasitoid C. floridanum trial. For suitability parameters on each host exposed separately to each of the three parasitoid species, we measured parasitoid emergence (parasitoid success), parasitoids that did not emerge (parasitoid cocoon mortality), the proportion of male offspring (parasitoid sex ratio), hosts that developed into moths (host success), hosts that died without developing into moths or producing a parasitoid (host mortality), parasitoids emerging from cocoon masses (brood size), and the developmental times of parasitoids and hosts. For C. sonorensis, the native host and the nonnative host were found to be similarly suitable. For C. vanessae, the native host was more suitable than the nonnative host. For C. floridanum, the native host was suitable, whereas the nonnative host was not; however, sublethal effects on both the native and nonnative hosts were observed. The differential suitability of the hosts observed in this study contributes to the understanding of this measure as a dynamic factor in the expansion of parasitoids into novel host species.

The water scavenger beetle, Hydrophilus acuminatus (Motschulsky) (Coleoptera: Hydrophilidae), has two types of feeding modes: carnivorous during the larval stage and omnivorous during the adult stage. To investigate how the beetles detect food, larvae were provided with pond snails and snail visceral mass and adults were provided with algae and thawed blood worms. Larvae found snails and visceral mass hidden in the filter paper (only “smell” could be used); however, visceral mass was found 22–27 minutes sooner than snails, 40–53 minutes. Time to find the visceral mass that was exposed (all senses could be used) or hidden (only “smell” could be used) showed similar values, 5.4–8.0 or 7.6–8.5 minutes, respectively. Adults found algae exposed on the filter paper in 54 ± 73 minutes (mean ± standard deviation), whereas no adults found the algae hidden in the filter paper. In contrast, all adults found the thawed blood worms in the exposed (10.3 ± 13 minutes) and hidden conditions (11.0 ± 12.7 minutes). Adults did not show feeding behaviour towards the algae or thawed blood worms in the transparent microtube (only “sight” could be used). These suggest that larvae use smell, whereas adults use smell and touch and/or taste to detect their food.

The Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins) (Coleoptera: Curculionidae) antiaggregation pheromone, 3-methylcyclohex-2-en-1-one (MCH), has been used since 2000 to protect high-value trees and stands throughout western North America. Operational treatments involve placing individual releasers on a 12 m × 12 m grid throughout the area to be protected. In this study, six widely spaced trap lines were established with aggregation attractant–baited traps located 1, 3, 9, 27, and 81 m from a location where an operational MCH release device was alternately either present or absent, and changes in catches caused by the MCH device were assessed at all distances. Trap catches were suppressed by about 70% at one and three metres, by 50% at nine metres, by 30% at 27 m, and not at all at 81 m. Inhibition by the MCH device varied with distance (m) from the source according to the function 0.79 − 0.092x0.51 (R2 = 0.986). Decline of attractant inhibition with distance from the MCH device was much less steep than would have been expected if catch inhibition had varied directly with the average airborne concentration of MCH.

Learning of chemical stimuli by insects can occur during the larval or adult life stage, resulting in changes in the imago chemotaxic behaviour. There is little information on learning in Tortricidae, and associative learning through metamorphosis is unknown in this group. Here, we evaluate the influence of olfactory aversive learning in Grapholita molesta (Busck) (Lepidoptera: Tortricidae) during the immature stage and determine if memory persists after metamorphosis. Larvae (10–12 days old) were conditioned to associate the odour of ethyl acetate with pulses of aversive electric shock. Insects were exposed to air, to the ethyl acetate odour, and to shock, in isolation or combination. After conditioning, both larvae and adults were tested in a two-choice olfactometer. Larvae exposed only to air or ethyl acetate increased legibility. Larvae trained with ethyl acetate and shock simultaneously exhibited significant avoidance to ethyl acetate. Avoidance was still present for at least 72 hours after metamorphosis. Thus, G. molesta has the ability to associate an odour to an aversive stimulus precociously, and this association is maintained through metamorphosis and persists into adulthood.

High-quality habitats presumably have the resources required to sustain relatively high rates of survival and reproduction. We assessed how habitat type and local environmental conditions determine the distribution of individuals of Canthon cyanellus (Coleoptera: Scarabaeidae), an eurytopic dung beetle, according to age category and sexual gonadic maturity. Beetles were surveyed in forest fragments, live fences, and pastures in Mexico. Individuals were categorised into six age categories according to the glandular volumes in males and oocyte number and length in females. Mature females in forest fragments were the most abundant females found among the habitats. Air humidity and soil hardness were positively and negatively related to mature female abundance, respectively. Mature beetles were the most abundant among males, and higher abundance of males occurred in forest fragments than in live fences and pastures. Light quantity was negatively related to the abundance of young males. Compared to forest fragments, females in pastures had larger oocytes. However, sites with higher soil hardness and air humidity had females with lower numbers of oocytes. Our results demonstrate that, although C. cyanellus occurs across a wide range of habitats, forest habitats might host sexually mature individuals, which translates into more effective individual dispersion and potential reproduction.

Forty-one belted kingfishers, Megaceryle alcyon (Linnaeus) (Aves: Coraciiformes: Alcedinidae), from Manitoba, Canada were examined for ectoparasites in 1995–2020. One species of chewing louse, Alcedoffula alcyonae Carriker (Phthiraptera: Ischnocera: Philopteridae), infested 48.8% of hosts. The mean intensity of infestation was 17.1, and mean abundance was 8.5 lice per bird. Distribution of infestation was highly aggregated. Although female lice outnumbered males, the sex ratio was not significantly different from 1.0. The ratio of nymphs to females was 2.6. An unidentified species of feather mite of the genus Proterothrix Gaud (Acari: Astigmatina: Proctophyllodidae) infested three of 35 hosts (8.6%). No mites were found in the quills of primary feathers from 19 birds, and no nasal mites were collected from 32.

Mating and receiving ejaculate can alter female insect physiology and postcopulatory behaviour. During mating, females receive both internal and external stimuli and different components in the ejaculate. In insects, these components consist mostly of sperm and male accessory gland secretions. Some of the most important changes associated with receiving male accessory gland secretions are a reduction in female sexual receptivity and an increase in oviposition. However, a clear function for these molecules has not been found in the Mexican fruit fly Anastrepha ludens (Loew) (Diptera: Tephritidae). Here, we tested how the stimulus of mating, receiving a full ejaculate, or only receiving accessory gland secretions can influence ovarian development and oviposition. Our results indicate that the stimulus of mating per se is enough to induce oviposition and increase egg laying in females even if ejaculate is not received, whereas receiving only accessory gland secretions does not increase ovarian development and is not enough to induce oviposition or increase egg production. Further research on the internal and external copulatory courtship of A. ludens will increase our understanding of the role of these secretions in stimulating oviposition independent of ejaculate effects. A biological function for male accessory gland secretions on female behaviour for A. ludens still needs to be found.

On 14 November 2018, a symposium Managing bark and ambrosia beetles with semiochemicals was held in Vancouver, British Columbia, Canada, at the Joint Meeting of the Entomological Society of America, the Entomological Society of Canada, and the Entomological Society of British Columbia. The focus was on the application of behavioural chemicals for management of bark and ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) in conifers and hardwoods in North America and Europe. Contributors included nine invited speakers from Canada, Slovakia, and the United States of America who summarised the current state of knowledge and latest technologies and shared career-long experiences and insights. This special issue features publications derived from those presentations.

Reproductive phenology of organisms is modulated by biotic and abiotic factors, with direct effects on the demography. This study describes the annual reproductive phenology of Dichotomius satanas (Harold, 1867) (Coleoptera: Scarabaeidae, Scarabaeinae) of the cloud forest in eastern Mexico, through the morphological changes in the reproductive systems of individuals and their relationship with climatic conditions. Three stages of sexual maturity were recognised as occurring throughout the year: immature, maturing, and mature – with a higher occurrence of immature individuals. Abundance of immature and maturing females was explained by minimum temperature, but none of the environmental variables considered was related to mature females. Abundance of immature and maturing males was related to precipitation, while abundance of mature males was related to minimum temperature and precipitation. The phenology of D. satanas was markedly seasonal with a single peak of abundance corresponding to the reproductive period during the warm and rainy season, thus indicating a univoltine pattern of reproduction. Immature females were recorded before immature males, and no synchrony was observed between the maturing and mature males and females. We provide information pertaining to the reproductive biology of coprophagous beetles and highlight the importance of reproductive phenology as a tool with which to understand future environmental scenarios.

We made 28 collections of black flies (Diptera: Simuliidae) at 24 locations in central and northeastern Washington state, United States of America, and identified 10 species in three genera, including Simulium arcticum Malloch, which we studied cytogenetically. We analysed 745 larvae of S. arcticum cytogenetically from nine of the 11 sites where it occurred; five sites had small sample sizes. For the collections with large sample sizes, the distribution of S. arcticum may have a geographic pattern. Larvae in western tributaries of the Columbia River have the sex-linked IIL-2 inversion and heterozygotes for the IS-1 autosomal polymorphism in abundance but lack the IIL-21 sex-linked inversion, whereas larvae in eastern tributaries of the Columbia River possess the IIL-21 inversion but lack IIL-2 and the IS-1 inversions. A cytotype new to science, S. arcticum IIL-81, occurs in some larvae at the Methow River in the eastern Cascades region. All females, regardless of location, possess enhanced (Ce Ce) centromere bands in their IIL-chromosomes, whereas all males possess the enhanced, thin (Ce Ct) centromere band dimorphism. The Methow River had nine types of chromosomally identified males in 2019 and eight types in 2020.

The sexual behaviour of the blister beetle Epicauta atomaria (Germar) (Meloidae: Meloinae: Epicautini), a pest that affects diverse crops of economic importance in South America, was evaluated for the first time under laboratory conditions. Twelve pairs of E. atomaria adults were collected from low-lying roadsides adjacent to grazed areas in Diamante, Entre Ríos, Argentina. To describe the sexual behaviour of this species, the number of events and their duration within different courtship phases in E. atomaria males were compared. An ethogram was built, showing that males perform three different behaviours during courtship phases: the quiescent period, antennal rubbing, and mounting. Our results showed that, during courtship, the number of events and the time of the mounting were low and significantly lower compared to behaviours undertaken during the quiescent period and antennal rubbing. In conclusion, the courtship of E. atomaria was clearly dominated by the quiescent period and antennal rubbing. To date, this is the first study to investigate sexual behaviour in E. atomaria, providing a foundation for future phylogenetic studies.

When I accepted the invitation to serve as the lead-off speaker for the symposium Managing Bark and Ambrosia Beetles with Semiochemicals on which this special issue is based, I noted that everything one needed to know was published in Seybold et al. (2018), a really good review of the subject. So, I took another course. About 25 years ago, I gave an oral presentation in the form of a letter to an imaginary graduate student. It seemed to go over well, so I decided to do it again. Here is a version of that letter to Sarah, the latest prospective graduate student conjured up by my imagination.

In this work, we used measures of diversity and biogeographic patterns to evaluate the response of dung-beetle assemblages (Coleoptera: Scarabaeidae: Scarabaeinae) at two cattle ranches with different management systems on the southern Mexican High Plateau. The number of individuals and biomass were used as the primary diversity attributes of the assemblage. The 1D and 2D true diversity indexes of these attributes were examined, and the attributes were classified according to Halffter’s biogeographical patterns. In total, 1375 Scarabaeinae adults were collected, representing 11 species and seven genera. Site management regime did not significantly affect species richness or assemblage structure when the number of individuals was considered. However, species diversity and biomass turnover were higher in the system with holistic management than in that with semitechnified management. The proportions of Halffter’s biogeographical patterns also differed between the two production systems. In conclusion, the location under holistic management, despite having cattle production, contained a significant proportion of the Scarabaeinae species that are typical of the Mexican High Plateau. In contrast, the semitechnified system negatively impacted beetle abundance, leading to half the individuals, the dominance of species with high biomass, and the absence of groups typical of the region.

Seven species of Turdidae (Aves: Passeriformes) in Manitoba, Canada were examined for chewing lice (Phthiraptera) in 1993–2019: Turdus migratorius (N = 570), Catharus ustulatus (N = 135), Catharus guttatus (N = 49), Catharus minimus (N = 12), Catharus fuscescens (N = 1), Sialia sialis (N = 4), and Sialia currucoides (N = 3). Five species of lice on T. migratorius had a prevalence of 24.0% and a mean intensity of 16.7. Overall prevalence for lice on C. ustulatus, C. guttatus, and C. minimus was 25.0%–59.2%; mean intensity was 7.0–23.3. On S. sialis, the prevalence was 50.0%; mean intensity was 10.0. No lice infested C. fuscescens or S. currucoides. Infestation parameters for each louse–host combination are provided. Louse infestations were highly aggregated. Female lice were more prevalent than males, especially for Ricinus elongatus (Phthiraptera: Amblycera: Ricinidae) infesting T. migratorius (eight males; 81 females), or there was no significant deviation from 50:50. Infestation parameters were higher for adult T. migratorius than for juveniles or feathered chicks but not significantly so. Mean intensity was greater in spring than in fall. Louse abundance was lower than on hosts of similar size in Manitoba and lower than on thrushes in other studies.

In many organisms, habitat affects ecological and genetic diversity and, for certain species, it is expected that a large population should have higher genetic diversity than a smaller population. We analysed the genetics of males of the orchid bee, Eulaema nigrita (Hymenoptera: Apidae) and examined the links between local abundance and habitat with genetic diversity. We also investigated the impact of landscape features on genetic population structure, through microsatellite and mitochondrial DNA analysis, among populations found across 700 km of Brazilian Atlantic forest fragments. We found that genetic variation was not a function of local abundance, but it correlated significantly with habitat. There was significant but low genetic differentiation among populations. We found a single mitochondrial DNA haplotype in all sequenced specimens, which may be widespread throughout the Atlantic forest. Our results reinforce the idea that orchid bees can fly long distances. High-dispersal capacity, together with insufficient time in eventual isolation, can directly contribute to the high degree of similarity among populations for this species, despite their wide geographical distribution.

The daylily gall midge, Contarinia quinquenotata (Loew) (Diptera: Cecidomyiidae), is an ornamental pest of daylilies, Hemerocallis spp. Linneas (Asphodelaceae). Originally native to Asia, this pest was accidentally introduced to western North America, and it is believed to occur throughout other parts of North America even though its presence has not been confirmed. Using an online survey of gardeners across Canada’s “Maritimes” (the region that includes the provinces of New Brunswick, Nova Scotia, and Prince Edward Island), we determined that symptoms of the pest occurred at multiple sites across Nova Scotia, but we received no reports from Prince Edward Island or New Brunswick. Sequencing the cytochrome c oxidase 1 gene of the samples submitted by community scientists, we confirmed the daylily gall midge occurs at multiple sites across Nova Scotia. A common garden study that included 517 daylily varieties found that yellow-flowering varieties were almost twice as likely to be affected as nonyellow varieties. Early-flowering varieties were more likely to be attacked than later-flowering varieties. For each day that the date at first flowering was delayed, the likelihood of gall midge attack decreased by 16%. To avoid or mitigate damage where the daylily gall midge occurs, selecting late-flowering varieties with nonyellow flowers can be a useful complement to destructing infested flower buds.