Field releases of the exotic parasitoid Trissolcus japonicus (Hymenoptera: Scelionidae) and survey of native parasitoids attacking Halyomorpha halys (Hemiptera: Pentatomidae) in Michigan

An adventive population of the exotic parasitoid wasp, Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), discovered in Michigan in 2018, is a promising biological control agent of the invasive Halyomorpha halys (Stål) (Hemiptera: Pentatomidae). Following its discovery, field releases of Tr. japonicus were conducted over 2 yr in southern Michigan, to test how release size or release frequency impacts establishment. Sentinel eggs of H. halys and of the native Podisus maculiventris (Say) (Hemiptera: Pentatomidae) were used alongside yellow sticky cards to monitor parasitoids. In 2019 and 2020, 7,200 Tr. japonicus were released at 16 sites. Monitoring between 2019 and 2021 yielded only 49 individuals. The captures suggest reproductive activity and overwintering success in the field but do not allow for evaluation of best release methods. Parasitism by native parasitoids was below 7%, which is similar to other states and unlikely to provide sufficient control of H. halys. The placement of sentinel eggs or sticky traps either in the lower or middle canopy of trees did not influence parasitoid capture rates. Frozen and fresh H. halys sentinel eggs were attacked at the same rate, but more native parasitoids emerged from frozen eggs. We did not find signs of nontarget effects on P. maculiventris thus parasitism rates overall were very low. These results could indicate dispersal of Tr. japonicus from the release sites or slow population growth. The latter may be due to the relatively low densities of H. halys in Michigan or may stem from the small founding size of our laboratory colony.

Illuminating a Dark Taxon: Revision of European Trichacis Förster (Hymenoptera: Platygastridae) reveals a glut of synonyms

The parasitoid wasp genus Trichacis Förster is revised for Europe. Examination of historical and modern collections combined with DNA barcoding revealed the presence of only a single species in Europe, Trichacis tristis (Nees, 1834), redescribed here. Fourteen new synonymies are proposed for T. tristis: T. abdominalis Thomson, 1859 syn.nov.; T. bidentiscutum Szabó, 1981 syn.nov.; T. didas (Walker, 1835) syn.nov.; T. fusciala Szabó, 1981 syn.nov.; T. hajduica Szabó, 1981 syn.nov.; T. illusor Kieffer, 1916 syn.nov.; T. nosferatus Buhl, 1997 syn.nov.; T. pisis (Walker, 1835) syn.nov.; T. persicus Asadi & Buhl, 2021 syn.nov.; T. pulchricornis Szelényi, 1953 syn.nov.; T. quadriclava Szabó, 1981 syn.nov.; T. remulus (Walker, 1835) syn.nov.; T. vitreus Buhl, 1997 syn.nov.; T. weiperti Buhl, 2019 syn.nov.. Four species are transferred to Amblyaspis Förster: A. afurcata (Szabó, 1977) comb. nov., A. hungarica (Szabó, 1977), comb. nov., A. pannonica (Szabó, 1977) comb. nov., and A. tatika (Szabó, 1977) comb. nov. Intraspecific variation, biological associations, and taxonomic history are discussed. DNA barcodes are provided and analyzed in the context of worldwide Trichacis and its sister genus Isocybus Förster.

The second record of Platyscelio (Hymenoptera: Scelionidae) in South America

The presence of Platyscelio (Platygastroidea, Scelionidae) in the Neotropical region is confirmed. After a recent record from French Guiana, a second specimen of Platyscelio was found in samples from the Republic of Suriname, being a new record for the fauna of this country.

 

Deployment of Aggregation-Sex Pheromones of Longhorned Beetles (Coleoptera: Cerambycidae) Facilitates the Discovery and Identification of their Parasitoids

Longhorned beetles (Coleoptera: Cerambycidae) include many species that are among the most damaging pests of managed and natural forest ecosystems worldwide. Many species of cerambycids use volatile chemical signals (i.e., pheromones) to locate mates. Pheromones are often used by natural enemies, including parasitoids, to locate hosts and therefore can be useful tools for identifying host-parasitoid relationships. In two field experiments, we baited linear transects of sticky traps with pheromones of cerambycid beetles in the subfamily Cerambycinae. Enantiomeric mixtures of four linear alkanes or four linear alkanes and a ketol were tested separately to evaluate their attractiveness to hymenopteran parasitoids. We hypothesized that parasitoids would be attracted to these pheromones. Significant treatment effects were found for 10 species of parasitoids. Notably, Wroughtonia ligator (Say) (Hymenoptera: Braconidae) was attracted to syn-hexanediols, the pheromone constituents of its host, Neoclytus acuminatus acuminatus (F.) (Coleoptera: Cerambycidae). Location and time of sampling also significantly affected responses for multiple species of parasitoids. These findings contribute to the basic understanding of cues that parasitoids use to locate hosts and suggest that pheromones can be used to hypothesize host relationships between some species of cerambycids and their parasitoids. Future work should evaluate response by known species of parasitoids to the complete blends of pheromones used by the cerambycids they attack, as well as other odors that are associated with host trees of cerambycids.

A fortuitous find: a unique haplotype of Ooencyrtus nezarae Ishii (Encyrtidae: Encyrtinae) discovered in Florida

The adventive arrival of biological control agents circumvents the regulatory process by introducing exotic species to control invasive pests and is generally followed by post hoc risk evaluation. The bean plataspid, Megacoptacribraria (Fabricius) (Hemiptera: Plataspidae), is an invasive pest of leguminous crops in the south-eastern United States that was eventually followed by two parasitoid wasps from its range in the eastern hemisphere, Paratelenomussaccharalis (Dodd) (Scelionidae) and Ooencyrtusnezarae Ishii (Encyrtidae). In North Central Florida, sentinel egg masses, intended to capture Paratelenomussaccharalis, instead yielded Ooencyrtusnezarae, which was previously known only from Alabama (Ademokoya et al. 2018). Two generations of O.nezarae were subsequently reared in the laboratory. COI sequences from the Florida population of O.nezarae differed by 1.3% from the Alabama population and the presence of a different haplotype suggests the possibility of a separate introduction. Laboratory parasitism rates, sex ratios, morphology, molecular diagnosis and implications for agriculture are discussed.

Windborne long-distance migration of malaria mosquitoes in the Sahel

Over the past two decades efforts to control malaria have halved the number of cases globally, yet burdens remain high in much of Africa and the elimination of malaria has not been achieved even in areas where extreme reductions have been sustained, such as South Africa^1,2. Studies seeking to understand the paradoxical persistence of malaria in areas in which surface water is absent for 3-8 months of the year have suggested that some species of Anopheles mosquito use long-distance migration³. Here we confirm this hypothesis through aerial sampling of mosquitoes at 40-290 m above ground level and provide-to our knowledge-the first evidence of windborne migration of African malaria vectors, and consequently of the pathogens that they transmit. Ten species, including the primary malaria vector Anopheles coluzzii, were identified among 235 anopheline mosquitoes that were captured during 617 nocturnal aerial collections in the Sahel of Mali. Notably, females accounted for more than 80% of all of the mosquitoes that we collected. Of these, 90% had taken a blood meal before their migration, which implies that pathogens are probably transported over long distances by migrating females. The likelihood of capturing Anopheles species increased with altitude (the height of the sampling panel above ground level) and during the wet seasons, but variation between years and localities was minimal. Simulated trajectories of mosquito flights indicated that there would be mean nightly displacements of up to 300 km for 9-h flight durations. Annually, the estimated numbers of mosquitoes at altitude that cross a 100-km line perpendicular to the prevailing wind direction included 81,000 Anopheles gambiae sensu stricto, 6 million A. coluzzii and 44 million Anopheles squamosus. These results provide compelling evidence that millions of malaria vectors that have previously fed on blood frequently migrate over hundreds of kilometres, and thus almost certainly spread malaria over these distances. The successful elimination of malaria may therefore depend on whether the sources of migrant vectors can be identified and controlled.

Developing a vocabulary and ontology for modeling insect natural history data: example data, use cases, and competency questions

Insects are possibly the most taxonomically and ecologically diverse class of multicellular organisms on Earth. Consequently, they provide nearly unlimited opportunities to develop and test ecological and evolutionary hypotheses. Currently, however, large-scale studies of insect ecology, behavior, and trait evolution are impeded by the difficulty in obtaining and analyzing data derived from natural history observations of insects. These data are typically highly heterogeneous and widely scattered among many sources, which makes developing robust information systems to aggregate and disseminate them a significant challenge. As a step towards this goal, we report initial results of a new effort to develop a standardized vocabulary and ontology for insect natural history data. In particular, we describe a new database of representative insect natural history data derived from multiple sources (but focused on data from specimens in biological collections), an analysis of the abstract conceptual areas required for a comprehensive ontology of insect natural history data, and a database of use cases and competency questions to guide the development of data systems for insect natural history data. We also discuss data modeling and technology-related challenges that must be overcome to implement robust integration of insect natural history data.

Seasonal parasitism and host specificity of Trissolcus japonicus in northern China

The brown marmorated stink bug, Halyomorpha halys (Stål), native to China, Japan, and Korea, has emerged as a harmful invasive pest of a variety of crops in North America and Europe. The Asian egg parasitoid Trissolcus japonicus has been identified as the most promising agent for classical biological control of invasive H. halys populations. A 4-year study evaluated the fundamental and ecological host ranges of T. japonicus as well as its phenology and impact on H. halys populations in fruit orchards in its native range in northern China. In laboratory no-choice tests, developmental suitability of eight non-target host species for T. japonicus was demonstrated by the successful production of progeny on the majority (>85%) of non-target host species tested. In field-collected, naturally laid egg masses, T. japonicus was the most abundant parasitoid associated with H. halys and Dolycoris baccarum, but was also sporadically found in Plautia crossota. Furthermore, it was regularly reared from sentinel egg masses of Menida violacea, Arma chinensis, and Carbula eoa. The only species that did not support development in the laboratory and field was Cappaea tibialis. Besides the benefit of having a high impact on H. halys populations in Northern China, the risk assessment conducted in the area of origin indicates that native Pentatomidae in North America and Europe could be negatively impacted by T. japonicus. Whether the benefits of T. japonicus outweigh the possible risks will have to be evaluated based on the outcome of additional host range studies in the two invaded regions.

Radiation hybrid mapping of cataract genes in the dog

PURPOSE

To facilitate the molecular characterization of naturally occurring cataracts in dogs by providing the radiation hybrid location of 21 cataract-associated genes along with their closely associated polymorphic markers. These can be used for segregation testing of the candidate genes in canine cataract pedigrees.

METHODS

Twenty-one genes with known mutations causing hereditary cataracts in man and/or mouse were selected and mapped to canine chromosomes using a canine:hamster radiation hybrid RH5000 panel. Each cataract gene ortholog was mapped in relation to over 3,000 markers including microsatellites, ESTs, genes, and BAC clones. The resulting independently determined RH-map locations were compared with the corresponding gene locations from the draft sequence of the canine genome.

RESULTS

Twenty-one cataract orthologs were mapped to canine chromosomes. The genetic locations and nearest polymorphic markers were determined for 20 of these orthologs. In addition, the resulting cataract gene locations, as determined experimentally by this study, were compared with those determined by the canine genome project. All genes mapped within or near chromosomal locations with previously established homology to the corresponding human gene locations based on canine:human chromosomal synteny.

CONCLUSIONS

The location of selected cataract gene orthologs in the dog, along with their nearest polymorphic markers, serves as a resource for association and linkage testing in canine pedigrees segregating inherited cataracts. The recent development of canine genomic resources make canine models a practical and valuable resource for the study of human hereditary cataracts. Canine models can serve as large animal models intermediate between mouse and man for both gene discovery and the development of novel cataract therapies.

Early transposable element insertion in intron 9 of the Hsf4 gene results in autosomal recessive cataracts in lop11 and ldis1 mice

Lens opacity 11 (lop11) is an autosomal recessive mouse cataract mutation that arose spontaneously in the RIIIS/J strain. At 3 weeks of age mice exhibit total cataracts with vacuoles. The lop11 locus was mapped to mouse chromosome 8. Analysis of the mouse genome for the lop11 critical region identified Hsf4 as a candidate gene. Molecular evaluation of Hsf4 revealed an early transposable element (ETn) in intron 9 inserted 61 bp upstream of the intron/exon junction. The same mutation was also identified in a previously mapped cataract mutant, ldis1. The ETn insertion altered splicing and expression of the Hsf4 gene, resulting in the truncated Hsf4 protein. In humans, mutations in HSF4 have been associated with both autosomal dominant and recessive cataracts. The lop11 mouse is an excellent resource for evaluating the role of Hsf4 in transparency of the lens.