North American Host Research Articles

Outbreak of Septoria leaf spot caused by Sphaerulina musiva on Populus × euramericana in China.

In June 2023, severe leaf spots were noted in Populus × euramericana cv 'Nanlin95' plantations located in the Nanjing Baguazhou Wetland Park (32°09'16.97″N, 118°48'16.74″E) of Jiangsu Province and Populus × canadensis cv 'Sacrau 79' and Populus × canadensis cv 'Guariento' in the Liyuan Village in Nanyang City (32°53'43.70″N, 112°17'29.12″E) of Henan Province, respectively. The disease incidence in both locations could reach 97.9% (556 out of 568 trees) and 98.9% (2409 out of 2436 trees), respectively. The initial symptoms appear as numerous small and circular spots (1.59 to 3.18 mm in diameter) with gray or tan centers and dark-brown margins on the leaves. As the spots age, they sometimes enlarge, often coalesce, and may extend down the petioles. Diseased leaves and petioles were both surface sterilized with 75% ethanol for 30 seconds. With the aid of a hand lens, pycnidia (brown to black, spherical in profile, 90 to 250 µm diam) were easily picked out in the center of the spots and subsequently transferred into 1 mL sterilized water for preparing the spore suspension plated on KV8 medium amended with 100 mg/liter streptomycin sulfate and 50 mg/liter chloramphenicol. After 12 days of incubation, 86 single-spore isolates were obtained and identified as typical Septoria-like fungi according to morphological features, including slow-growing, gray or black colonies with pink mucilaginous matrix and hyaline, straight or curved conidia (size = 25 to 59 × 3.5 to 4 μm; septa = 1 to 6). Species identification was further validated by PCR amplification and sequencing of the internal transcribed spacer (ITS) region with ITS1/ITS4 primer pairs. Multiple sequence alignments with ClustalW revealed that the obtained ITS sequences of 86 isolates were 100% identical to each other. A BLAST search in GenBank indicated that the selfsame sequences of two representative isolates (isolate BGZ11 of Jiangsu Province, accession no. OR660379; isolate KZB22 of Henan Province, accession no. OR711499) shared 99.8% identity (494 of 495 bp) and 100% identity (504 of 504 bp) with related sequences of Sphaerulina musiva (Peck) Quaedvlieg, Verkley, and Crous (syn. = Septoria musiva Peck) in GenBank (MN275187; KF251619), respectively. Furthermore, we used a S. musiva-specific PCR assay (Abraham et al. 2018) on symptomatic leaf samples collected from the plantation. Each sample consisted of 20 cut-out leaf spots per leaf. Eight of the 10 samples were positive for S. musiva DNA. To confirm pathogenicity, six sterile tissue culture of poplar plants (Populus trichocarpa and Populus × euramericana cv 'Nanlin895') were respectively transplanted into pots and grown in a greenhouse for a week and for a month with an 18-h photoperiod augmented with sodium lamps and a 20°C (day)/16°C (night) temperature regime. Inoculations were conducted by spraying the plants with conidia suspension (106 conidia/mL) (LeBoldus et al. 2010). Control plants were sprayed with distilled water. Leaf spots were developed on the inoculated P. trichocarpa leaves at one week and P. × euramericana cv 'Nanlin895' leaves at 10 days after inoculation while no symptoms were observed on the control plants. The fungus S. musiva was successfully reisolated from all symptomatic leaves fulfilling Koch's postulates. Sphaerulina musiva only causes an endemic leaf spot disease on its natural North American host Populus. deltoides (Feau et al. 2010; Ostry 1987). However, on susceptible Populus species (e.g., P. balsamifera, P. trichocarpa, P. maximowiczii) and hybrids, S. musiva causes not only leaf spots but also severely damaging stem and branch cankers (Jeger et al. 2018; LeBoldus et al. 2009; Sondreli et al. 2020). To our knowledge, this is the first report of S. musiva causing leaf spots on poplar in China. Large-scale timber imports (e.g., cut branches, isolated bark, wood with and without bark) potentially lead to anthropogenic-facilitated transport of this pathogen. This outbreak of Septoria leaf spot underscores the potential threat of this pathogen to P. × euramericana in China, where it is widely planted as a keystone forestry species.

Pediatric Orthopaedic Observerships in North America for International Surgeons: A Qualitative Study Exploring Motivations, Relevance, and Alternate Learning Platforms.

Given the growing interest among international surgeons to participate in North American clinical observerships, it is essential to incorporate international surgeons' views to further enhance the program's applicability, value, and accessibility. In this qualitative follow-up study, we explored the motivations, relevance, and opinions about alternate learning platforms among the international surgeons who had participated in a pediatric orthopaedic clinical observership in North America. Using a semistructured interview guide, international surgeons who had participated in a North American pediatric orthopaedic observership during 2009 to 2019 were interviewed until data saturation and inductive thematic saturation were reached. Twenty-one international surgeons representing 15 different countries (1 from a low-income country, 10 from a lower middle-income country, 8 from an upper middle-income country, and 2 from a high-income country) were interviewed. The most commonly cited motivations for doing a clinical observership were to advance clinical training and learn specific skills. The clinical and nonclinical skills gained during the observership, such as utilizing an integrated team approach and open communication style, were helpful to most interviewees; however, several respondents highlighted the critical need to adapt and modify surgical indications, techniques, and skills to suit their local environment and limited resource availability. Although respondents were interested in exploring virtual learning models to save time and expense, several preferred a hybrid model, including access to remote learning opportunities and sharing their own clinical experiences with the North American hosts. Identifying the visiting surgeon's motivation for participation can allow North American hosts to align their clinical exposure more closely with the unique needs and aspirations of the international surgeons and enable a more relevant exchange of clinical and nonclinical skills. Use of a blended learning model, including in-person and virtual learning platforms, and the missed opportunity of having the international surgeons share their clinical experiences and skills with their North American counterparts should be explored further.

Orthopaedic trauma observerships in North America for international surgeons: the visitors' perspective.

A survey was distributed to overseas surgeons who participated in an orthopaedic trauma observership from 2009 to 2020. Surgeons were identified through North American institutions previously recognized by the authors as having hosted international observerships. Information gathered included participant demographics, details of and perceived impact of the observership, and barriers faced before, during, and after the program. Responses from 148 international surgeons (ISs) from 49 countries were analyzed. Sixty percent of observerships were at academic programs, 57% lasted 1-3 months, and 60% were self-funded. Participants identified cost and housing as primary barriers. After completing their observership, lack of funding, equipment and support staff, and excessive workload prevented participants from implementing changes at their clinical practice. Most observers believed that they gained relevant clinical (89%) and surgical knowledge (67%) and developed a professional network of North American hosts (63%). The most common suggested changes to the observership were greater hands-on experience in the operating room and structured goal setting relevant to the visiting surgeon. Visiting surgeons find North American orthopaedic trauma observerships helpful in improving their surgical and clinical skills. However, financial constraints and resource limitations at their clinical practice and limited operative experience during the observership present barriers to maximizing this clinical experience. To enhance the relevance of clinical observerships for ISs and impact global orthopaedic trauma care, the unique needs and challenges facing ISs must be addressed. IV-Cross-Sectional Study.

Voles, shrews and red squirrels as sources of tick blood meals and tick-borne pathogens on an island in southwestern Finland

Molecular identification of the previous blood meal source of a questing tick (Acari: Ixodidae) from blood meal fragments was proposed a few decades ago. Following this, several blood meal assays have been developed and published, but none of them have been taken into widespread use. Recently, novel retrotransposon-based qPCR assays designed for detecting blood meal fragments of North American host species were published. We wanted to assess their function with host species present in Finland.Questing ticks were collected by cloth dragging in August-September 2021 from an island in southwestern Finland. DNA was extracted from Ixodes ricinus nymphs (n=438) and qPCR assays applied to identify larval blood meal sources (voles, shrews and red squirrels) and screen for several tick-borne human pathogens and other microbes with pathogenic potential [Borrelia spp. (including specific assays for Borrelia afzelii, Borrelia garinii, Borrelia valaisiana), Anaplasma phagocytophilum, Babesia spp., Rickettsia spp., and Neoehrlichia mikurensis].The probability of a nymph having fed as larva on either a vole, shrew or red squirrel was 0.34 (0.30 – 0.38; 95% confidence interval). Bacteria of the genus Borrelia were the most common pathogens detected, with host-specific probabilities of carrying Borrelia of 0.30 (0.18 – 0.44) for nymphs that had fed on voles, 0.23 (0.14 – 0.35) for nymphs that had fed on shrews, and 0.42 (0.28 – 0.58) for nymphs that had fed on red squirrels. Other microbes were rarely acquired from these hosts, apart from N. mikurensis from voles.This study highlights that shrews and red squirrels may equal voles as blood meal sources for I. ricinus larvae. Overall, variation in proportions of blood meals provided by these animals may be high across even proximate study areas. All studied host species appeared to be important sources for particularly Borrelia afzelii, and voles also for N. mikurensis.

Long-term changes in the prevalence of the crayfish plague pathogen and its genotyping in invasive crayfish species in Czechia

The widespread presence of North American alien crayfish in Europe is a major driver of native crayfish population declines, mainly because they are chronic carriers of the oomycete Aphanomyces astaci responsible for crayfish plague. Screening for the crayfish plague pathogen in host populations has become a common practice across Europe, but sampling usually covers spatial but not temporal variation. Our study focuses on the current situation in Czechia, where screening for A. astaci was first conducted in the mid-2000s. We provide data about the distribution and prevalence of this pathogen at almost 50 sites with three host crayfish: the spiny-cheek crayfish Faxonius limosus, signal crayfish Pacifastacus leniusculus, and marbled crayfish Procambarus virginalis. Among these sites were 20 localities that were resampled several years (usually more than a decade) after the original screening for A. astaci. We did not detect any A. astaci infection in two studied P. virginalis populations but documented several new hotspots of highly infected P. leniusculus in Czechia, and the first site with the coexistence of the latter with F. limosus. Our data suggest that despite some fluctuations, A. astaci prevalence in North American host populations generally does not tend to change significantly over time; we only observed two cases of a significant increase and one of a significant decrease. We no longer detected A. astaci in several originally weakly infected populations, but our data suggest it likely still persists in these areas and threatens native crayfish populations. At the single known site in the country where P. leniusculus and F. limosus coexist, we documented the presence of the same A. astaci genotype group in both crayfish species, likely due to interspecific transmission of the pathogen from the former host to the latter. However, genotyping of A. astaci in infected host individuals still supported the link between specific pathogen genotypes and crayfish hosts, suggesting that assessment of sources of mass mortalities from the pathogen genotyping is feasible in European regions where the mutual contact of different American crayfish species is uncommon.

Insect Herbivores of Ferns along the Pacific Northwest Coast of North America

Fifteen species of insect herbivores were discovered on ferns growing along the Pacific northwest coast of North America. These included insects from the orders: Diptera in the families Anthomyiidae, Cecidiomyiidae and Syrphidae: Lepidoptera in the families Erebidae, Tortricidae and Noctuidae: Hymenoptera in the family Tenthredinidae: Hemiptera in the family Aphididae and Coleoptera in the family Curculionidae. The present study illustrates these associations that provides new world and North American host records of fern herbivores. The fossil record of these families is used to determine if the most ancient of these insects (dating from the Mesozoic) are now mostly restricted to ferns and the most recent ones (dating from the Cenozoic) are mostly polyphagous, feeding on ferns as well as various angiosperms. Results indicate that the insect clades belonging to the most ancient families, such as Aneugmenuss and Strongylogaster in the Tenthredinidae and Dasineura and Mycodiplosis in the Cecidiomyiidae, appear to be monophagous on ferns.

Global Phylogeography of Salmonid Ectoparasites of the Genus Gyrodactylus, with an Emphasis on the Origin of the Circumpolar Gyrodactylus salmonis (Platyhelminthes: Monogenea)

The wageneri species group of Gyrodactylus contains the following molecularly confirmed salmonid parasites in Asia: Gyrodactylus taimeni Ergens, 1971, Gyrodactylus magnus Konovalov, 1967, Gyrodactylus brachymystacis Ergens, 1978, and Gyrodactylus derjavini Mikhailov, 1975; in Europe it contains the following: Gyrodactylus derjavinoides Malmberg, Collins, Cunningham, and Jalali, 2007, Gyrodactylus truttae Gläser, 1974, Gyrodactylus teuchis Lautraite, Blanc, Thiery, Daniel, and Vigneulle, 1999, Gyrodactylus lavareti Malmberg, 1956, Gyrodactylus salvelini Kuusela, Ziętara, and Lumme, 2008 (presented herein as a junior synonym of Gyrodactylus salmonis Yin and Sproston, 1948), and Gyrodactylus salaris Malmberg, 1957, with the lone confirmed North American exception being G. salmonis. The mitochondrial DNA (cox1, 1545 bp) of this group shows a star-like phylogenetic expansion that began 2.05 ± 0.4 million years ago (mya), estimated from the mean distance of the cox1 gene (dMCL = 0.267) using a tentative, potentially high-end, divergence rate of 0.13/Myr. European G. salaris on Thymallus thymallus and Asian G. magnus on Thymallus arcticus have been separated for 1.95 Myr (dMCL = 0.253). The nuclear ITS rDNA region (1,245 bp) of G. salmonis was nearly uniform among North American populations of Oncorhynchus mykiss, Oncorhynchus clarkii, Oncorhynchus nerka, Salvelinus fontinalis, and Salmo salar (and non-native Salmo trutta) as well as on Salvelinus alpinus (under the synonym G. salvelini) from Lake Inari, Finland. Gyrodactylus salmonis is distal in a monophyletic subclade labeled by an apomorphic 56 bp insertion in the ITS1, shared by the European parasites G. lavareti (host: Coregonus lavaretus), Gyrodactylus pomeraniae Kuusela, Ziętara, and Lumme, 2008 (host: Rutilus rutilus), and Gyrodactylus bliccensis Gläser, 1974 (host: Alburnus alburnus). This subphylogeny suggests that a particular host switch from cyprinids to salmonids may have occurred less than 1.8 mya in the Old World [dMCL = 0.234 G. pomeraniae vs (G. salmonis, G. lavareti)] and possibly again among coregonine hosts and Salvelinus 1.2 mya (dMCL = 0.156). Although hypothetical, a transition from coregonines to charr (notably the widely distributed and adaptable Salvelinus alpinus) potentially could have occurred in a proglacial refugium leading to circumpolar distribution of G. salmonis and a secondary transition to other North American hosts. The maximum cox1 genetic distance within G. salmonis on all hosts was dMCL = 0.032, at the same level as in multihosted European G. salaris (dMCL = 0.032), suggesting circa 250,000 yr of population expansion with these parasites since a temporal, coinciding bottleneck.

Pediatric Orthopaedic Observerships in North America for International Surgeons: Perceived Barriers and Opportunities for Visitors and Hosts.

Despite recommendations for high-income countries to partner with low-income and middle-income countries to expand surgical access, little is known about the barriers that are faced by international surgeons (ISs) who participate in short-term clinical observerships in North America and the barriers that are encountered by their North American (NA) hosts. Surveys were distributed to ISs who participated in a pediatric orthopaedic observership in North America in 2009 to 2019 and their NA hosts to assess the perceived barriers that are faced by both partners and identify possible opportunities for improvement. Responses were received from 181 ISs and 46 NA hosts. The ISs reported facing a variety of barriers prior to, during, and after completion of their NA observerships, including financial burden, language and cultural barriers, and challenges with local accommodations and transportation. Only 49% of ISs reported that their NA hosts had sought feedback from them. Barriers noted by the NA hosts included financial burden, logistical challenges with hosting, language barriers, and lack of support from their co-faculty/staff. At least 43% of NA hosts reported that their observership program was unfunded. Based on the survey responses, potential areas that may enhance the observership experience include funding support, creating a centralized data bank of pediatric subspecialty opportunities that are available at each sponsoring institution, a pre-visit orientation for the visiting surgeon, improving inclusivity by addressing language and cultural barriers, improving access to observing surgical procedures, obtaining post-visit feedback, and creating a virtual community of international visitors and NA hosts for an ongoing exchange of ideas and resources. The ISs who participated in a pediatric orthopaedic clinical observership and their NA hosts identified limited funding as a major barrier. There are several opportunities for enhancing this unique learning experience and exploring the role of contextual remote learning for all participants. Additional studies are needed to investigate the value of clinical observerships for ISs, including the downstream impact of such opportunities on capacity-building, bidirectional learning, and improving patient care.

Fungal Interactions and Host Tree Preferences in the Spruce Bark Beetle Ips typographus.

The spruce bark beetle Ips typographus is the most damaging pest in European spruce forests and has caused great ecological and economic disturbances in recent years. Although native to Eurasia, I. typographus has been intercepted more than 200 times in North America and could establish there as an exotic pest if it can find suitable host trees. Using in vitro bioassays, we compared the preference of I. typographus for its coevolved historical host Norway spruce (Picea abies) and two non-coevolved (naïve) North American hosts: black spruce (Picea mariana) and white spruce (Picea glauca). Additionally, we tested how I. typographus responded to its own fungal associates (conspecific fungi) and to fungi vectored by the North American spruce beetle Dendroctonus rufipennis (allospecific fungi). All tested fungi were grown on both historical and naïve host bark media. In a four-choice Petri dish bioassay, I. typographus readily tunneled into bark medium from each of the three spruce species and showed no preference for the historical host over the naïve hosts. Additionally, the beetles showed a clear preference for bark media colonized by fungi and made longer tunnels in fungus-colonized media compared to fungus-free media. The preference for fungus-colonized media did not depend on whether the medium was colonized by conspecific or allospecific fungi. Furthermore, olfactometer bioassays demonstrated that beetles were strongly attracted toward volatiles emitted by both con- and allospecific fungi. Collectively, these results suggest that I. typographus could thrive in evolutionary naïve spruce hosts if it becomes established in North America. Also, I. typographus could probably form and maintain new associations with local allospecific fungi that might increase beetle fitness in naïve host trees.

Detrimental effects of a failed infection by a co-invasive parasite on a native congeneric parasite and its native host.

Biological invaders often are accompanied by co-invasive parasites that can alter ecosystem function and established native host-parasite relationships. When these co-invasive parasites establish in a community, they can affect native host fitness and native parasite infection intensity, prevalence, and success within the native host. The mosquito, Aedes triseriatus, is North American host to protozoan parasite, Ascogregarina barretti. In geographic regions invaded by the mosquito Aedes albopictus, A. triseriatus may also be infected by A. albopictus' co-invasive parasite, Ascogregarina taiwanensis. We tested the hypotheses that: 1) The presence of a co-invasive parasite will negatively affect native parasite fitness, yielding decreased infection intensity, prevalence, and infection success, which could be caused by immune induction of the host or inter-parasite competition, and 2) Coinfection with the native and co-invasive parasites will negatively affect host fitness, yielding increased larval development time and decreased survival and reproductive fitness, caused by increased costs of infection. In our coinfection experiments we find that any exposure to the co-invasive parasite resulted in decreased survivorship and increased development time of the host A. triseriatus, with or without coinfection by the native parasite. Exposure to both co-invasive and native parasites yielded reduced native parasite infection intensity in the host larva and reduced native parasite propagule production in the resulting male adults. Together, these results indicate not only the potential for the co-invasive parasite to alter the native host-parasite relationship, but to impact native host population dynamics.

Prevalence and new host records of nasal mites (Acari: Rhinonyssidae: Ereynetidae: Turbinoptidae) in birds from Arkansas and Illinois (United States)

ABSTRACT Avian nasal mites are obligate endoparasites that spend their entire life in the respiratory system of birds. In North America, bird nasal mites are represented by several unrelated families in three orders of mites: Rhinonyssidae (Mesostigmata), Ereynetidae (Trombidiformes), and Cytoditidae and Turbinoptidae (Sarcoptiformes). The most-diverse and commonly encountered family of nasal mites is Rhinonyssidae, in which mite species may have different levels of specificity to host orders, families, or even to species. In this study, birds from Arkansas and Illinois in the United States were surveyed for nasal mites. Of 430 birds examined, 58 individuals (13.4%) and 30 of 106 bird species (28%) were infested with nasal mites. Levels of mite prevalence were similar to results reported from previous studies (25-45% of species). The 58 infested birds with nasal mites belonged to 4 orders, 11 families, 24 genera, and 30 species. Rhinonyssidae was the most commonly found family and was represented by 15 species. Nineteen new North American host records are added, the majority being found within the bird families Parulidae and Emberizidae. Three new host records are added in Turdidae and Accipitridae with nasal mites from the families Ereynetidae and Turbinoptidae.

Descriptions of seven new species of Brueelia Kéler 1936 (Phthiraptera: Ischnocera: Philopteridae) from North American sparrows (Aves: Passeriformes: Passerellidae), and review of host use by Brueelia vulgata

ABSTRACT Seven new species of Brueelia are described from North American hosts. They are: Brueelia melospizae sp. nov. from Melospiza georgiana, M. lincolnii, M. melodia, and M. m. fallax; Brueelia californica sp. nov. from Melozone crissalis; Brueelia canyonica sp. nov. from Melozone fusca; Brueelia tenebrosa sp. nov. from Passerella iliaca; Brueelia chlorurae sp. nov. from Pipilo chlorurus; Brueelia hesperides sp. nov. from Pooecetes gramineus confinis; Brueelia cassiopeia sp. nov. from Spizella passerina arizonae and S. p. passerina. Brueelia vulgata and Brueelia angustifrons are redescribed and illustrated. An updated host checklist of the Brueelia-complex species known from the Emberizidae and Passerellidae, and a key to the males of the species described herein are provided. http://www.zoobank.org/urn:lsid:zoobank.org:pub:6D472E90-DCD1-471F-8A9C-B260C2F2074D

Aphanomyces astaci genotypes involved in recent crayfish plague outbreaks in central Italy.

The oomycete Aphanomyces astaci is the causative agent of crayfish plague in native European freshwater crayfish. Molecular analyses showed that several distinct genotype groups of this pathogen, apparently associated with different original host taxa, are present in Europe. Tracking their distribution may contribute to understanding the introduction pathways of A. astaci. We used microsatellite markers to genotype the pathogen strains involved in 7 mass mortalities of the endangered indigenous crayfish Austropotamobius pallipes that occurred between 2009 and 2016 in the Abruzzi and Molise regions, central Italy. Three A. astaci genotype groups (A, B, and D, with the latter represented by 2 distinct multilocus genotypes) were identified, suggesting the existence of multiple infection sources even in a relatively small area. Most crayfish plague episodes were due to genotype groups associated with the North American host species Pacifastacus leniusculus and Procambarus clarkii, although these crayfish are not widespread in the study area. A. astaci genotype group A was detected not only in crayfish plague outbreaks but also in apparently healthy Astacus leptodactylus imported for human consumption from Armenia and kept alive in an aquaculture facility. Imports of chronically infected A. leptodactylus from Armenia, Turkey, and possibly Eastern Europe are an underestimated introduction pathway for A. astaci. Although we cannot exclude the presence of latently infected native populations of A. pallipes in the region, A. astaci infections in legally imported crayfish species considered vulnerable to crayfish plague may represent further reservoirs of A. astaci; this should be reflected in the policies regulating the trade of live crayfish.

Native birds exploit leaf-mining moth larvae using a new North American host, non-native Lonicera maackii

ABSTRACTI document observations of birds feeding on the larvae of the leaf-mining moth Phyllonorycter emberizaepenella (Gracillariidae) in Michigan, USA. The larvae were feeding on Amur honeysuckle, Lonicera maackii (Caprifoliaceae), a non-native plant that has not been documented as a host for any species of Gracillariidae in North America, and which has few records of use by invertebrate herbivores anywhere in its range. Most bird observations were of chickadees (Paridae), which have been previously recorded feeding on leaf-mining insects. Observations also include three species of warblers (Parulidae) and one kinglet (Regulidae), which represent the first documentation of these families feeding on leaf-mining moth larvae. I describe this novel multitrophic interaction between a non-native plant, a native insect, and native vertebrate predators, and discuss the potential spread of the moth in North America, its use as a food source by birds, and the ecological implications.

Long term post-release impacts of the introduced parasitoid Peristenus relictus (Hymenoptera: Braconidae) on Lygus spp. (Hemiptera: Miridae) populations in California

The European Lygus spp. parasitoid Peristenus relictus (Ruthe) was released into California between 1998 and 2004. Four release sites, including one in the Central Valley and three along the Monterey Bay, were monitored from 1999 to 2015. Lygus spp. and P. relictus populations were monitored in alfalfa, weedy non-crop vegetation, and commercial strawberries. An experimental field cage study was also conducted to measure the contribution of both P. relictus and resident predators to Lygus spp. mortality. Results from both caging and longitudinal studies demonstrated that P. relictus had a negative impact on Lygus spp. nymphal densities.Annual percent parasitism peaks ranged from 45 to 71% in alfalfa or non-crop vegetation, which were either correlated with host densities or demonstrated a delayed density dependent response. Lygus spp. population reductions of over 90% were recorded at five of six sampling locations by 2011–2012. An increase in Lygus spp. densities was observed at two release sites during the last two years of monitoring in the Monterey Bay region and may be related to climate. In-season nymphal densities were correlated with winter temperatures, as warmer than average winters may have affected diapause and accelerated population growth rates. We consider this study, which corroborates the preference by P. relictus for congeneric North American host species, the biological control value of this parasitoid’s establishment, and climate as a possible contributor to Lygus spp. population dynamics, to be a valuable contribution to understanding biological control of Lygus spp. by P. relictus.

Additional records of Gnathostomes in North American hosts

Since the original description of the nematode genus Gnathostoma Owen, 1836 which was based upon material collected from a stomach nodule of a tiger that died after being imported into the London Zoological Garden, the endemic occurrence of members of the group has been observed principally in southern Asia, Africa, Philippines, Australia, China, and Japan. Species of the genus, either as larva or adult, parasitize a variety of hosts, including arthropods, fishes, amphi­bia, reptiles, birds, and mammals. Of the latter, such carnivores as Felidae, Canidae, and Mustelidae most often have been reported infected, although infre­quent reports of infections in cattle, pigs, rodents, and man have appeared in the literature.

An Update to the Adventive Aphids (Hemiptera: Aphidoidea) of America North of Mexico, with Notes on Intercepted Species

Abstract. Two hundred and sixty-two adventive aphids (Hemiptera: Aphidoidea) have been previously reported in North America north of Mexico. We update this to include 25 previously unrecorded species, and include information on the location and date of first discovery, biogeographic origin, and economically important North American hosts for these species. The number of adventive species introduced per year has decreased overall since 1930.We discuss aphids intercepted at United States ports of entry and identified by the Systematic Entomology Laboratory from 2000–2016 and comment on how the composition of species intercepted may affect the adventive species that become established.

Hosts, Nesting Behavior, and Ecology of Some North American Spider Wasps (Hymenoptera: Pompilidae), II

This monograph is a continuation of a multiyear study of the genera and species of North American spider wasps (Pompilidae) and their spider host families, genera and species, nesting behavior, ecology, and natural communities. The study enlarges and enhances host preference, nesting behavior, and ecological information for 77 North American pompilid taxa. The first North American Pompilidae records for the families Tengellidae and Segestriidae, both from central coastal California, are reported herein. New host spider genera and species are listed for many of the pompilid species, including the first North American host record for Dipogon (Dipogon) g. graenicheri. The first detailed observations of male and female behavior in Arachnospila arcta are described.

Variation in phenotype and virulence among enzootic and panzootic amphibian chytrid lineages

The Global Panzootic Lineage of the fungus Batrachochytrium dendrobatidis (Bd-GPL) is threatening amphibians worldwide. In contrast, four lineages (Bd-Brazil, Bd-CH, Bd-Cape, and Bd-Korea) that diverged early in the history of Bd have not yet been directly linked to amphibian declines. Bd likely evolves in response to strong selective pressure imposed by hosts and the environment, leading to differences among pathogen phenotypes and genotypes that may directly affect virulence. Here, we report on variation in phenotype, genotype, and virulence of Bd-Brazil and Bd-GPL. Specifically, we (i) used a controlled infection experiment to compare virulence between one Bd-Brazil and three Bd-GPL isolates on a North American amphibian host (Lithobates sylvaticus), (ii) tested for relative phenotypic and genotypic differentiation among Bd isolates from Brazil, and (iii) tested for possible correlations between environmental variables and Bd phenotypes. We found substantial variation in virulence among Bd-GPL isolates and found that our Bd-Brazil isolate showed virulence comparable to an average North American Bd-GPL. North American hosts infected with a Bd-GPL isolate from Panama did not show significant mortality. Bd phenotypes varied significantly across sampling locations; these phenotypes were neither spatially clustered nor correlated with any environmental variables. Additionally, we found a surprising lack of correlation between genotypic divergence and zoospore and zoosporangium sizes in our sample. Although Bd-Brazil was less virulent infecting L. sylvaticus than one Bd-GPL isolate, this endemic lineage still caused ∼50% mortality in our experimental North American hosts. This indicates that Bd-Brazil has the potential to kill amphibians if introduced to naive wild populations. Our findings underscore that characterizing virulence of multiple Bd isolates and lineages is important for understanding the evolutionary history and diversity of Bd.

Nest sanitation does not elicit egg ejection in a brown-headed cowbird host.

Most passerine birds practice nest sanitation whereby they remove debris from their nest. Nest sanitation has been posited as a pre-adaptation for egg ejection by hosts of avian brood parasites. However, relatively few North American hosts of the brood parasitic brown-headed cowbird (Molothrus ater) eject cowbird eggs to the detriment of their fitness. In this study, I added either a piece of flagging tape or a pine cone bract scale along with an artificial cowbird egg to nests of the red-winged blackbird (Agelaius phoeniceus) to determine whether the act of nest sanitation would elicit egg ejection. All red-winged blackbirds removed the debris within 24h, but all individuals also accepted the cowbird eggs and this rate of ejection did not differ from that in nests that only received a cowbird egg. While nest cleaning and egg ejection are similar mechanically, they differ cognitively and egg ejection is not elicited in red-winged blackbirds during the act of removing debris from their nests.