Search

The spotted-wing drosophila, Drosophila suzukii Matsumura, is an exotic species in North America and represents a major threat to fruit production. Efforts to manage D. suzukii have focused primarily on insecticides, but such controls may, at times, be unreliable, given that D. suzukii larvae are often ensconced within fruit. The fruit interior, however, may represent suitable foraging substrates for carnivorous/entomopathogenic nematodes. In preliminary trials, a rare nematode species, Oscheius onirici Torrini et al., was shown to be highly virulent against D. suzukii when the nematodes were applied directly to fly larvae. To address the more important question of whether this nematode would be as virulent when applied to fruit, we set up assays in which blueberries were infested with D. suzukii larvae and then sprayed with O. onirici infective juveniles (IJs). Across two laboratory trials, O. onirici IJs suppressed D. suzukii puparia by 78.2%. Oscheius onirici IJs were able to search effectively within fruit substrates, find the fly larvae therein, and kill the flies before they could pupariate. Oscheius onirici, therefore, may represent a viable new bio-control agent for D. suzukii management and should be field-tested across a broader diversity of cropping systems.

Microbial symbiotic interactions, mediated by small molecule signaling, drive physiological processes of higher order systems. Metabolic analytic technologies advancements provide new avenues to examine how chemical ecology, or conversion of existing biomass to new forms, changes over a symbiotic lifecycle. We examine such processes using the tripartite relationship between nematode host Steinernema carpocapsae, its obligate mutualist bacterium, Xenorhabdus nematophila, and the insects they infect together. We integrate trophic, metabolomics, and gene regulation analyses to understand insect biomass conversion to nematode or bacterium biomass. Trophic analysis established bacteria as the primary insect consumers, with nematodes at trophic position 4.37, indicating consumption of bacteria and likely other nematodes. Significant, discrete metabolic phases were distinguishable from each other, indicating the insect chemical environment changes reproducibly during bioconversion. Tricarboxylic acid cycle components and amino acids were significantly affected throughout infection. These findings contribute to an ongoing understanding of how symbiont associations shape chemical environments.TeaserEntomopathogenic nematodes act as an apex predator in some ecosystems through altering chemical environments of their prey.

Numbers of northern bobwhite, Colinus virginianus (L.), have decreased during the past 50 years in Oklahoma. It is unknown if the availability of grounddwelling arthropods on which bobwhite chicks rely for 80% of their protein requirements plays a role because little is known of ground-dwelling arthropod communities in bobwhite habitats of western Oklahoma. We used pitfall traps to sample community composition and size classes of ground-dwelling arthropods along transects that spanned four vegetation zones at two wildlife management areas occupied by bobwhites in western Oklahoma and recorded the abundance of quail nests per zone. After collecting and identifying 58,020 arthropods from families known to be eaten by quail, we found 60% of the arthropods ideally suited for quail consumption were in riparian zones, and that most quail nested in upland zones. Approximately 15% of nests were in the zones with the most abundant arthropods in the Packsaddle Wildlife Management Area during 2013, compare...

In a search for an entomopathogenic nematode to control cranberry insect pests, three Oscheius populations (Rhabditidae) were recovered through the Galleria-bait method from one sample taken in a wild cranberry marsh in Jackson County, Wisconsin, USA. Morphological studies with light microscopy and scanning electron microscopy, as well as molecular analyses of the near-full-length small subunit rDNA gene, D2/D3 expansion segments of the large subunit rDNA gene, internal transcribed spacer, and mitochondrial cytochrome oxidase subunit 1 (CoxI) genes revealed this as Oscheius onirici, a species recently described from a karst cave soil of central Italy. The species belongs to the dolichura-group and is characterized by its DNA sequences; hermaphroditic reproduction; and males not found. A Bacillus-like bacterium appears to be associated with this nematode based on our microscopic and SEM observations; however its identity and persistent association with the nematode has not been confirmed. Nonetheless, this nematode is capable of infecting and killing the sparganothis fruitworm Sparganothis sulfureana Clemens (Lepidoptera: Tortricidae), the brown-banded cockroach Supella longipalpa Fabricius (Blattodea: Ectobiidae), and the cranberry fruitworm Acrobasis vaccinii Riley (Lepidoptera: Pyralidae), under laboratory conditions, and each in less than 72 hr. The mealworm Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae) and the greater wax moth Galleria mellonella Linnaeus (Lepidoptera: Pyralidae), are also susceptible, but take 3.5 and 5.2 days to die, respectively. This species is a new potential bio-control agent on insects.

In 2015 and 2016, surveys of entomopathogenic nematodes were conducted in the wild cranberry habitats of Wisconsin. The purpose of the survey was to find a biological control agent for control of insect pests of cranberries. Two nematodes, Oscheius onirici Torini (Rhabditida: Rhabditidae) and Heterorhabditis georgiana Nguyen (Rhabditida: Rhabditidae), were collected in this survey. Laboratory trials show that applications of either O. onirici or H. georgiana resulted in 75% and 65% mortality rates, respectively, when applied to sparganothis fruitworm Sparganothis sulfureana Clemens (Lepidoptera: Tortricidae) larvae. In replicated field trials, both nematode species were also shown to significantly suppress the redheaded flea beetle, Systena frontalis Fabricius (Coleoptera: Chrysomelidae) populations. Collectively, these findings suggest that these nematodes may be promising bio-insecticides for cranberries.