Mortality causes in the widespread ibis and spoonbill genera Threskiornis, Plegadis and Platalea: a global review

Improving success rates of classical weed biocontrol programs is an ongoing effort that requires a variety of different approaches. Previous assessments indicated biocontrol agent taxonomy and feeding characteristics and weed life history traits are associated with better control outcomes. We examined weed biocontrol releases for correlations between biocontrol agent and target weed traits associated with different levels of reported establishment and control. Data collated in the 5th edition of ‘Biological Control of Weeds: A World Catalogue of Agents and Their Target Weeds’ were used as the basis for this global analysis. Published literature was used to augment the catalog with data for eight biocontrol agent traits and four target weed traits. Biocontrol agent establishment and impact data were analyzed against these traits using generalized linear mixed models and categorical models, respectively. Analyses for biocontrol agent establishment reveal the following agent traits were correlated with a greater probability of establishment: being an internal feeder, feeding on above-ground plant tissues, multivoltine agents and agents that feed during both their adult and immature life stages. Insect taxon did not affect establishment except for the order Lepidoptera, which had the lowest establishment probability. For weed traits, those occurring in aquatic or riparian habitats were associated with a higher probability of biocontrol agent establishment. Regarding agent impact, using the definition categories in the catalog, agents feeding externally and on vegetative plant tissues, multivoltine agents and those with both adult and immature plant-feeding life stages were strongly correlated with greater impact. Perennials, reproducing only vegetatively and invading aquatic or riparian habitats were associated with greater biocontrol impact. Our findings could facilitate both the prioritization of invasive plants targeted for biocontrol and the selection of suitable biocontrol agent candidates, which should further improve biocontrol project outcomes.

Predatory insects and spiders were collected from apple orchards in two geographic regions of Central Washington State, United States of America to assess seasonal phenology and diversity of the generalist predator community. Arthropods were collected from orchard canopy every 3–7 days over two growing seasons (March–October) at seven organically managed and two insecticide-free orchards. Over 35 000 specimens and 80 species of spiders (Araneae), ladybeetles (Coleoptera: Coccinellidae), lacewings (Neuroptera), and predatory true bugs (Hemiptera) were collected. Composition of insect and spider communities differed between the two geographic regions. Indicator species analysis identified several species that had a significant association with one of the two regions. Counts of the most common taxa were examined in detail on a calendar date basis to determine seasonal phenology of adult and immature stages. We observed substantial differences among taxa in number of generations, seasonal timing of first appearance in orchards, overwintering stages, and seasonal occurrence of the adult and immature life stages in orchards. Understanding seasonal phenology of natural enemies in orchards is a core requirement in integrated pest management programs for apple pests, and results of this study provide this information for the generalist predator community of orchards in the Pacific Northwest.

We reviewed the literature on the role of temperature in transmission of zoonotic arboviruses. Vector competence is affected by both direct and indirect effects of temperature, and generally increases with increasing temperature, but results may vary by vector species, population, and viral strain. Temperature additionally has a significant influence on life history traits of vectors at both immature and adult life stages, and for important behaviors such as blood-feeding and mating. Similar to vector competence, temperature effects on life history traits can vary by species and population. Vector, host, and viral distributions are all affected by temperature, and are generally expected to change with increased temperatures predicted under climate change. Arboviruses are generally expected to shift poleward and to higher elevations under climate change, yet significant variability on fine geographic scales is likely. Temperature effects are generally unimodal, with increases in abundance up to an optimum, and then decreases at high temperatures. Improved vector distribution information could facilitate future distribution modeling. A wide variety of approaches have been used to model viral distributions, although most research has focused on the West Nile virus. Direct temperature effects are frequently observed, as are indirect effects, such as through droughts, where temperature interacts with rainfall. Thermal biology approaches hold much promise for syntheses across viruses, vectors, and hosts, yet future studies must consider the specificity of interactions and the dynamic nature of evolving biological systems.

Insect lineages have crossed between terrestrial and aquatic habitats many times, for both immature and adult life stages. We explore patterns in molecular evolutionary rates between 42 sister pairs of related terrestrial and freshwater insect clades using publicly available protein-coding DNA sequence data from the orders Coleoptera, Diptera, Lepidoptera, Hemiptera, Mecoptera, Trichoptera, and Neuroptera. We furthermore test for habitat-associated convergent molecular evolution in the cytochrome c oxidase subunit I (COI) gene in general and at a particular amino acid site previously reported to exhibit habitat-linked convergence within an aquatic beetle group. While ratios of nonsynonymous-to-synonymous substitutions across available loci were higher in terrestrial than freshwater-associated taxa in 26 of 42 lineage pairs, a stronger trend was observed (20 of 31, pbinomial = 0.15, pWilcoxon = 0.017) when examining only terrestrial-aquatic pairs including fully aquatic taxa. We did not observe any widespread changes at particular amino acid sites in COI associated with habitat shifts, although there may be general differences in selection regime linked to habitat.

Adaptive radiation and speciation in Rhipicephalus ticks: A medley of novel hosts, nested predator-prey food webs, off-host periods and dispersal along temperature variation gradients

Locomotor performance constitutes a major component of whole‐animal performance and is involved in several fitness‐related behaviors. Locomotor capabilities may also correspond positively or negatively to sexually selected traits (e.g., male ornamentation and/or courtship displays). Negative correlations are predicted if secondary sexual traits take the form of morphological modifications that impose physical or energetic limitations. We tested this cost of secondary sexual traits by comparing locomotor performance in male Schizocosa wolf spiders that exhibit two distinct phenotypes. These phenotypes vary in the presence/absence of a morphological feature assumed to function as sexual ornamentation—foreleg brushes. Given the conspicuously large brushes of hair on the brush‐legged phenotype, we expected these males to suffer in locomotor performance. We tested this cost by comparing locomotor performance among male phenotypes (brush‐legged and non‐ornamented) and females at immature and adult life stages. We did not find strong support for costs of brushes on locomotion. First, brush‐legged males showed similar average speeds and endurance as both non‐ornamented males and females. Second, while brush‐legged males were slower at maximum speeds than non‐ornamented males as matures (but not as immatures), they were no slower than mature females. Further, we found no variation in endurance among phenotypes or life stages. Finally, brush size did not correspond to speed. Patterns of morphological variation in traits other than ornamentation may explain these patterns: when morphological variation in leg lengths was accounted for, differences in maximum speed among groups disappeared. We suggest that the faster speeds achieved by non‐ornamented males arise as a by‐product of selection on morphology and musculature potentially necessary for vigorous courtship.

Grape phylloxera, Daktulosphaira vitifoliae Fitch, is an important pest of grapevines (Vitis vinifera L.) (Vitaceae). The distribution and frequency of phylloxera clone lineages vary within infested regions of Australia, suggesting the introduction of separate lineages of D. vitifoliae with host associations. Virulence levels of particular phylloxera clones may vary on V. vinifera, but much of this evidence is indirect. In this study, we directly tested the performance of phylloxera clones on V. vinifera using an established excised root assay and a new glasshouse vine assessment. In the root assay, grape phylloxera clones differed in egg production and egg to adult survivorship. In the vine assay, clones differed in the number of immature and adult life stages on roots. In addition vine characteristics, including mean stem weight, root weight, leaf chlorophyll and leaf area, were affected by different phylloxera clones. The two most widespread clones displayed high levels of virulence. These results point to only some phylloxera clones being highly virulent on V. vinifera, helping to explain patterns of field damage, phylloxera distributions and continued survival and production of V. vinifera vines in some infested areas.

Pselactus spadix tunnels timber structures in the marine environment. Recent studies reported a cosmopolitan distribution for this weevil, which is frequently found in harbour and port areas. P. spadix feeds on timber (hardwood and softwood) in immature and adult life stages, but its digestion of wood components had not been investigated. Using dry weight analyses of tunnel walls and frass produced, P. spadix adults consumed Scots pine with soft rot decay at a rate of 1.59 ± 0.37 mg d m 1 and the digestibility of this substrate was 57.96 ± 5.89 ( i.e. for 100 mg consumed SR-pine, 58 mg was digested). Using gravimetric analysis to quantify structural wood components in tunnel walls and frass, P. spadix adults were found to digest cellulose, lignin and hemicellulose with digestibility coefficients of 82.2, 41.2 and 14.5 respectively. Fourier Transform Infrared (FTIR) spectroscopy analyses of tunnel walls and frass of adults and larvae from soft rotted pine also indicated digestion of all structural components, with larvae digesting cellulose and lignin more efficiently than adults. When FTIR was employed to analyse adult tunnel walls and frass from undecayed pine, cellulose and hemicellulose were digested, but no evidence of lignin digestion was found. This study shows that adults digest lignin when soft rot is present and suggests a symbiotic function of wood degrading microorganisms.

Successful propagation of California sumac shrubs, Rhus laurina (Nutt.), in an environmentally controlled greenhouse regimen, provided an excellent factitious host for large scale rearing of the citrus thrips, Scirtothrips citri (Moulton). Peak population levels for immature and adult life stages per shrub were ca. 2500 and 515, respectively, during a 4 week infestation cycle.

Insecticides are the most commonly used tactic to control western flower thrips (WFT), Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), on greenhouse cucumber. However, WFT has developed resistance to several of the insecticides presently in use. In addition, some of these insecticides adversely affect greenhouse biological control agents used to control WFT, resulting in subsequent pest resurgence. Therefore, there is a need to identify novel insecticides with unique modes of action for use in integrated pest management (IPM) programs to effectively control WFT with minimal impact on associated biological control agents. In laboratory bioassays conducted in 2001, immature and adult WFT and three associated greenhouse biological control agents: Amblyseius cucumeris Oudemans (Acarina: Phytoseiidae), Orius insidiosus Say (Hemiptera: Anthocoridae) and Encarsia formosa Gahan (Hymenoptera: Aphelinidae) were exposed to direct, direct/residual, and residual contact applications of the novel biopesticide, spinosad (Conserve 120 SC), and the industry standard for whitefly control, endosulfan (Thiodan 50 WP). In all three types of assay, spinosad was effective against immature and adult WFT life stages. It showed low toxicity to A. cucumeris, moderate toxicity to O. insidiosus and high toxicity to E formosa. Greenhouse studies involving exposure of immature and adult WFT and adult biological control agents to cucumber leaves sprayed previously with spinosad supported the laboratory data. Spinosad showed low toxicity to A. cucumeris exposed to leaves 1 day after treatment (DAT), moderate toxicity to O. insidiosus 1 and 8 DAT, and high toxicity to E. formosa up to 28 DAT. These data, along with spinosad's unique mode of action, suggest it would be a valuable reduced-risk control agent for greenhouse cucumber IPM programs.

The abundance of mosquitoes is strongly influenced by biotic and abiotic factors that act on the immature (aquatic) and adult (terrestrial) life stages. Rapid changes in land use and climate, which impact aquatic and terrestrial mosquito habitat, necessitate studying the ecological mechanisms, and their interplay with the changing environment, that affect mosquito abundance. These data are crucial for anticipating how environmental change will impact their roles as pests, disease vectors, and in food webs. We studied a population of Arctic mosquitoes (Aedes nigripes, Diptera: Culicidae) in western Greenland, a region experiencing rapid environmental change, to quantify spatial variation in adult abundance and reproduction. Using sweep nets, we collected about sevenfold more mosquitoes within the town of Kangerlussuaq and within a low‐elevation tundra valley compared to three other tundra locations. Dissections of adult female mosquitoes revealed that only 17% were gravid overall, with a range of 7–43% among sites. If gravid, mosquitoes matured an average of 60 eggs per individual—more in larger females. We found no indication of autogenous egg development. Analyses using our field data indicated that spatial variation in adult fecundity and survival of immatures could each account for a 10‐fold range in the per capita growth of mosquito populations. The availability of vertebrate hosts and aquatic habitat is changing in many parts of the Arctic and can be expected to influence Arctic mosquito abundance. In the Arctic, and elsewhere, life‐history data from natural populations of mosquitoes will significantly aid in understanding controls on the abundance of these globally ubiquitous insects.

Climate-based models simulating Culex mosquito population abundance in the Northeastern US were developed. Two West Nile vector species, Culex pipiens and Culex restuans, were included in model simulations. The model was optimized by a parameter-space search within biological bounds. Mosquito population dynamics were driven by major environmental factors including temperature, rainfall, evaporation rate and photoperiod. The results show a strong correlation between the timing of early population increases (as early warning of West Nile virus risk) and decreases in late summer. Simulated abundance was highly correlated with actual mosquito capture in New Jersey light traps and validated with field data. This climate-based model simulates the population dynamics of both the adult and immature mosquito life stage of Culex arbovirus vectors in the Northeastern US. It is expected to have direct and practical application for mosquito control and West Nile prevention programs.

BackgroundAmblyomma americanum and Rhipicephalus sanguineus (sensu lato) nymphs commonly feed on and transmit pathogens to dogs (Canis familiaris). Control of immature and adult tick life stages is necessary to fully protect animals. We evaluated efficacy of oral fluralaner (Bravecto®) against induced infestations with A. americanum and R. sanguineus (s.l.) nymphs on dogs in two experiments.MethodsIn each experiment, 10 dogs were administered oral fluralaner chewable tablets one time on Day 0 at a targeted minimum dose of 25 mg/kg body weight and 10 dogs remained non-treated controls. Dogs were infested with two groups of 50 A. americanum nymphs and two groups of 50 R. sanguineus (s.l.) nymphs on Days -1, 6, 28, 56 and 84. At 48 h and 72 h post-infestation, nymphs were collected from dogs, assessed as live or dead, and enumerated into categories defining attachment and engorgement status. Fluralaner efficacy was determined in separate analyses against all live nymphs and against live-fed nymphs, i.e. live nymphs that were attached to dogs at the time of collection and/or were engorged. Fluralaner was considered effective when mean numbers of live ticks were reduced in fluralaner-treated dogs by ≥ 90%.ResultsFluralaner efficacy against all live and live-fed A. americanum nymphs in the first experiment was > 94% on all collection days. Efficacy against all live R. sanguineus (s.l.) nymphs in the first experiment was > 96% on all collection days excluding the 48 h counts for infestations on Days 28 (83.7%), 56 (82.9%) and 84 (86.7%); efficacy against live-fed R. sanguineus (s.l.) nymphs was > 95% on all 48 h/72 h count days. Fluralaner efficacy against all live A. americanum nymphs in the second experiment was > 93% on all collection days for 8 weeks excluding the 48 h count for infestation on Day 56 (87.8%); efficacy against live-fed A. americanum nymphs was > 91% on all count days for 8 weeks. Efficacy against all live R. sanguineus (s.l.) nymphs in the second experiment was > 91% on all 72 h collection days except for infestations on Days 28 (76.8%) and 56 (86.3%); efficacy against live-fed R. sanguineus (s.l.) nymphs was 100% on all 72 h count days.ConclusionsA single administration of oral fluralaner to dogs is effective against A. americanum and R. sanguineus (s.l.) nymphs for up to 12 weeks.

Monitoring water quality with aquatic insects as sentinels requires taxonomic knowledge of adult and immature life stages that is not available in many parts of the world. We used deoxyribonucleic acid (DNA) barcoding to expedite identification of larval caddisflies from 20 sites in the headwaters of the Tigris River in northern Iraq by comparing their mitochondrial cytochrome c oxidase subunit I (COI) sequences to a global reference library (the Trichoptera Barcode of Life). We obtained full-length DNA barcodes for 16 COI haplogroups from 11 genera in 9 Trichoptera families. The most haplogroups and genera were recorded from Sulaimani Province. Two distinct COI haplogroups were found for the genus Psychomyia, and 5 haplogroups were found for Hydropsyche. The Hydropsyche COI haplogroups do not form a monophyletic clade with reference to the world fauna, but 4 out of 5 haplogroups are related to other Palearctic species. Three larval Rhyacophila specimens in a single COI haplogroup are closely related to specimens of Rhyacophila nubila Zetterstedt and Rhyacophila dorsalis (Curtis) from Europe, but adults from Iraq are needed to confirm their species identity.

To successfully implement surveillance or control strategies for mosquitoes, up-to-date knowledge of regional species composition is vital. The last report regarding mosquitoes (Diptera: Culicidae) in the Åland archipelago, southwestern Finland listed 19 species (Utrio, 1979). To determine the current species diversity, one collection trip was made to mainland Åland in 2015 and three in 2016. Mosquitoes (n = 3286) were collected as both adult and immature life stages from 88 collections within 29 1-km2 areas. Fifteen of the 19 previously reported species were obtained, leaving the current status of four species uncertain. At least 11 species previously not reported from Åland, but confirmed on the Finnish mainland, were collected. Aedes geminus Peus was identified based on examination of the gonostylus, and represents a new species distribution for Finland. Anopheles maculipennis s.s. Meigen was confirmed from cytochrome c oxidase subunit I (COI) and internal transcribed spacer 2 (ITS2) sequence data and is reinstated on the list of Finnish species, along with Ochlerotatus sticticus (Meigen). Dahliana geniculata (Olivier) was found in two locations, in 2 months, indicating that there is an established population in Åland. The present data confirm that at least 27 species inhabit mainland Åland, rising to 31 when historical data are included. The Finnish mosquito fauna is increased from 38 to 41 species.