Cricket Populations Research Articles

Preparing eugregarine parasites and their cricket host Acheta domesticus as a model for gregarine infection studies

The increasing global demand for house crickets (Acheta domesticus) necessitates effective health measures. Despite their abundance, the effects of gregarines on these hosts remain underexplored. We present a method for controlled gregarine infection and maintenance of gregarine-free cricket populations. This system, adapted from prior work, is essential for experiments on gregarine infection dynamics, providing insights into parasite evolution and host-parasite interactions within the Apicomplexa group. This protocol includes rearing and maintenance of gregarine-free cricket populations for experimental purposes, gregarine production for oocyst solution and cricket infection, and gregarine infection assessment.

Invasive vegetation encroachment modulates dual threats faced by island-endemic scaly crickets

The mechanisms by which non-native species impact island-endemic populations are varied and often convoluted. For effective invertebrate conservation where capacity is limited, it is vital to understand both direct and indirect species interactions. Those interactions define specific threats and therefore highlight possible solutions. We quantified several of the non-native species threats faced by an endemic scaly cricket, Discophallus ascension (family: Mogoplistidae), found on Ascension Island’s naturally barren coastlines. We hypothesized that encroaching non-native Mexican thorn Prosopis juliflora (1) directly reduced microclimate suitability, (2) indirectly increased resource competition with non-native species, and (3) indirectly increased non-native predation. Our aim was to assess how rapidly spreading Mexican thorn might reduce endemic cricket populations. Lab trials first confirmed the temperature and diet preferences of D. ascension. Mexican thorn significantly increased ground-level temperature but not above the estimated optimum for D. ascension within key habitat. Observed interspecific resource competition was significantly greater in habitat degraded by Mexican thorn and was driven by non-native ants, house crickets Gryllodes sigillatus and cockroaches Periplaneta americana. Recorded cricket predation was almost entirely by non-native rats Rattus rattus in barren habitat but primarily by ants in Mexican thorn habitat. Threats to D. ascension were therefore modulated by invasive vegetation, but driven by non-native insects and rats at all sites. We conclude that removal of vegetation alone is likely to reduce resource competition but not predation. Managing multiple invasive species is likely necessary for successful species conservation.

New volvovirus isolate from Thai domesticated house cricket, Acheta domesticus (Orthoptera: Gryllidae)

Abstract This study investigated the genomic characteristics of Acheta domesticus volvovirus (AdVVV) in a commercial cricket farming operation. BLAST analysis of the Acheta domesticus genome assembly identified sequences with high similarity to the AdVVV-Japan genome, suggesting AdVVV presence. PCR confirmed AdVVV infection in the A. domesticus breeding population from Nakhon Ratchasima farm, Thailand. The complete 2,516 nucleotide AdVVV-Thailand genome was reconstructed through targeted primer amplification and sequencing. It contained four open reading frames encoding hypothetical proteins, with a characteristic hairpin structure at the termini, consistent with other AdVVV isolates. Phylogenetic analysis revealed AdVVV-Thailand’s closer genetic affiliation with AdVVV-Japan compared to other isolates. Comparative analysis of coding sequences across five AdVVV isolates showed the highest variability in the hypothetical protein/putative capsid protein ORF1, with 64 variable sites out of 1086 bases, suggesting its significance in genetic diversity. In contrast, ORF2, ORF3, and ORF4 exhibited minimal variability. The majority of variations were singletons, with 85.33% confined to ORF1. This study confirmed AdVVV presence in a commercial cricket farm, reconstructed the AdVVV-Thailand genome, provided insights into its phylogeny and genetic diversity across isolates, highlighting the putative capsid protein’s role in driving variability. These findings enhance understanding of AdVVV genomics and evolutionary dynamics within cricket populations.

Suitability of containerized toxicant to control Solenopsis invicta (Hymenoptera: Formicidae) threatening cave species in Bexar County, Texas.

Several protected troglobitic invertebrate species are known to occur in caves on Joint Base San Antonio-Camp Bullis, Bexar County, Texas, United States. The United States Fish and Wildlife Service (USFWS) identified red-imported fire ant Solenopsis invicta (hereafter RIFA) (Buren 1972) as the primary threat to cave species' nutrient sources, cave crickets, Ceuthophilus secretus (Scudder 1894). Per the service's recommendations, Joint Base San Antonio-Camp Bullis currently implements boiling water mound injections with digging for RIFA control. However, treatment effectiveness is highly variable and largely dependent on the time of day, weather, and personnel diligence. Toxicants have been used for RIFA treatment throughout the world, but concerns exist that traditional applications of toxicant bait around caves might be accessible and inadvertently affect nontarget arthropods, including cricket populations. To mitigate this accessibility, physically limiting access to the toxicant from crickets may be an option. Our objectives were to (i) compare and evaluate the effectiveness of Amdro (Hydramethylnon) and Advion (Indoxacarb) granular baits housed in Ants-No-More Bait Stations (Kness MFG. Inc., Albia, IA) and (ii) evaluate the distance of effectiveness of each bait within a bait station. Ultimately, we observed a 98% reduction in RIFA mound abundance from both baits. Additionally, RIFA mounds within 10 m of the containerized toxicant were reduced by 70%. Our pilot study suggested that Ants-No-More Bait Stations are an effective way to reduce RIFA mounds by 70% if placed 10 m from each other. In practice, this could include bait stations completely covering a particular distance to a cave entrance or fewer bait stations in a ring barrier at a single radial distance to a cave entrance. Containerized toxicants may be a cost-effective and safe RIFA control option around protected cave environments, but further studies are needed to determine potential effects on nontarget arthropods, optimal bait station configuration, and potential effects of biomagnification.

Population structure and habitat preference of cave crickets (<i>Rhaphidophora</i> sp. (Orthoptera: Rhaphidophoridae)) in Sanghyang Kenit cave, Citatah karst area, West Java

Cave crickets are considered as a keystone species that can be used as a cave ecosystem bioindicator. Developing caves as tourism has considerable potential to disturb cave cricket populations. This study aimed to investigate cave cricket population structure and their habitat preference in Sanghyang Kenit cave one year after it developed into a show cave. Data were collected through standardized visual searching in three cave zones: entrance, twilight, and dark. Besides cave crickets, other macroarthropods discovered in each zone were also recorded. Abiotic parameters of habitat comprised air and soil temperatures, RH, soil moisture, soil pH, and light intensity were measured. Data were analyzed to show cave crickets abundance, density, sex ratio, and age structure. Statistical analysis comprising Kruskal Wallis, non-metric multidimensional scaling, and correlation tests were performed. The cave cricket population in Sanghyang Kenit belonged to a single species, Rhaphidophora sp. The population was around 78-108 individuals and distributed in all cave zones. The abundance and density in twilight and dark zones were significantly higher than in the entrance. The number of males outperformed females with a 2.16 ratio. Besides, the population was dominated by the sub-adult class. Environmental parameters of twilight and dark zones tended to be similar to one another compared to the entrance. Cave crickets preferred habitats with dark, humid, and acidic soil pH. Heteropoda sp. and Catagaeus sp. were considered potential predators. This study implies the importance of protecting cave crickets in Sanghyang Kenit.

A New Genus of Crickets (Orthoptera: Gryllidae) in Mid-Cretaceous Myanmar Amber

Crickets (Orthoptera: Grylloidea) are a highly diverse and successful group that due to their chirping are often heard more often than they are seen. Their omnivorous diet allows them to exist in a variety of terrestrial habitats around the world. In some environments, cricket populations can build up and become plagues, resulting in significant damage to seedling crops. A new genus and species of cricket, Pherodactylus micromorphus gen. et sp. nov. (Orthoptera: Gryllidae) is described from mid-Cretaceous Myanmar amber. The new genus is characterized by the following features: head without prominent bristles, pronotum longer than wide, middle of pronotal disk with two distinct large dark “eyespots”, fore leg robust and 3 apical spurs arranged on inner side of fore leg tibia. Shed portions of a lizard skin adjacent to the specimen reveal possible evidence of attempted predation.

A New Genus of Crickets (Orthoptera: Gryllidae) in Mid-Cretaceous Myanmar Amber

Crickets (Orthoptera: Grylloidea) are a highly diverse and successful group that due to their chirping are often heard more often than they are seen. Their omnivorous diet allows them to exist in a variety of terrestrial habitats around the world. In some environments, cricket populations can build up and become plagues, resulting in significant damage to seedling crops. A new genus and species of cricket, Pherodactylus micromorphus gen. et sp. nov. (Orthoptera: Gryllidae) is described from mid-Cretaceous Myanmar amber. The new genus is characterized by the following features: head without prominent bristles, pronotum longer than wide, middle of pronotal disk with two distinct large dark “eyespots”, fore leg robust and 3 apical spurs arranged on inner side of fore leg tibia. Shed portions of a lizard skin adjacent to the specimen reveal possible evidence of attempted predation.

A Biological Restoration Model for Contaminated Coastal Marshes and Islands Using the Life Cycle of Acheta domesticus to Establish Environmental Sustainability

Insects such as Acheta domesticus account for over half of marsh fish and migratory bird diet. Therefore, insects are very important to marsh and island ecosy stems and are susceptible to oil contamination, but little research has been done to study the effects of oil spills on cricket populations. The purpose of this experiment was to determine the effects of an oil spill event on Acheta domesticus mortality and hatch rate to establish environmental sustainability. The treatment groups included 0% oil contamination, 5% oil contamination and 10% oil contamination. The scientist counted the number of deaths in two-week, four-week, and six-week-old crickets after oil contamination. In addition, the scientist counted the number of hatchlings among treated cricket eggs. Error bar lines in the results section supported the scientist’s hypothesis that the crickets would be affected by oil contamination. In fact, over 90% of the 10% oil treatment group died and over 80% of the 5% oil treatment group died after five days of oil contamination in the six-week-old experiment. The scientist used a Gas Chromatography Mass Spectrometer to determine if benzene, toluene, ethylbenzene, or xylene (total) were present in the sediment samples. BTEX exposure is suspected to possibly cause insect mortality. These volatile organic compounds were present in the samples and were found in higher quantities in samples with higher concentrations of oil. The highest quantity of volatile organic compounds present was xylene. After studying the population dynamics of the tested Acheta domesticus, the scientist found that the two-week and four-week-old crickets’ survivability could fit a linear model while the six-week-old crickets fit an exponential model. The scientist used these models to observe how long it took each treatment group to approach zero, and the oiled groups grew closer to a population of zero significantly faster. For example, it took about twenty-seven days for the 10% treatment group’s population to approach zero whereas the control, 0% treatment group, took about seven days in the two-week-old cricket experiment. Overall, the six-week-old crickets had the highest mortality, and the cricket egg experiment resulted in extremely low hatch rate. Specifically, the highest number of crickets that hatched in an oiled replication either 5% or 10% oil was eight out of the five thousand eggs laid. Since the adult crickets are the most physically able to reproduce and the cricket eggs had low hatch rates, the cricket population would significantly decrease after an oil spill with 5% or more soil contamination. However, if the plant matter that crickets consume is still present in their environment, they may be able to recover.

Discovery of an acoustically locating parasitoid with a potential role in divergence of song types among sympatric populations of the bush cricket Mecopoda elongata

The bush cricket Mecopoda elongata provides a striking example of sympatric intraspecific divergence in mating signals. Five completely distinct song types are found in various parapatric and sympatric locations in South India. While there is convincing evidence that population divergence in M. elongata is being maintained as a result of divergence in acoustic signals, cuticular chemical profiles, and genital characters, the causes of the evolution of such divergence in the first place are unknown. We describe the discovery of a tachinid parasitoid with an orthopteroid hearing mechanism affecting M. elongata. This parasitoid may have a role in driving the extraordinary divergence that had occurred among M. elongata song types. Over two years we sampled individuals of three sympatric song types in the wild and retained individuals in captivity to reveal rates of parasitization. We found that all three song types were infected with the parasitoid but that there were significant differences among song types in their probability of being infected. The probability of tachinid parasitization also differed between the two sampling periods. Therefore, it is possible that parasitoid infection plays a role in song type divergence among sympatric bush cricket populations.

A silent orchestra: convergent song loss in Hawaiian crickets is repeated, morphologically varied, and widespread.

Host-parasite interactions are predicted to drive the evolution of defences and counter-defences, but the ability of either partner to adapt depends on new and advantageous traits arising. The loss of male song in Hawaiian field crickets (Teleogryllus oceanicus) subject to fatal parasitism by eavesdropping flies (Ormia ochracea) is a textbook example of rapid evolution in one such arms race. Male crickets ordinarily sing to attract females by rubbing their forewings together, which produces sound by exciting acoustic resonating structures formed from modified wing veins (‘normal-wing’). The resulting song is the target of strong sexual selection by conspecific females. However, male song also attracts female flies that squirt larvae onto males or nearby female crickets; the larvae then burrow into, consume, and ultimately kill the host. The flies thus impose strong natural selection on male song, producing silent males, which have spread rapidly in populations on two islands – Kauai and Oahu. On both islands, song loss is caused by genetic mutations that drastically reduce or eliminate sound-producing structures on the male forewing by feminising wing venation – these males are called ‘flatwing’. On recent visits to parasitized cricket populations, we discovered two additional wing phenotypes – ‘small-wing’ and ‘curly-wing’. These two phenotypes differ noticeably from flatwing, and from each other, but all have the effect of eliminating or reducing acoustic signals that attract the parasitoid fly. These discoveries illustrate how the evolutionary process can repeatedly, and through a remarkable variety of independent mechanisms, drive adaptation to the same selection pressure.

Seasonal abundance and distribution of the Farallon camel cricket, Farallonophilus cavernicolus Rentz, 1972 (Orthoptera: Rhaphidophoridae), and other arthropods on Southeast Farallon Island

We provide distribution and abundance information for Farallonophilus cavernicolusRentz, 1972, the Farallon camel cricket, and other commonly encountered ground dwelling arthropods (the tenebrionid beetles Coniontis sp. and Eleodes parvicollis Eschscholtz, 1829, Isopoda, and Microcoryphia) recorded during visits to the Southeast Farallon Island (SEFI) from 2013 through 2015. We found cricket populations in six caves and rock crevices, which were mapped and surveyed. One cave accounted for the greatest cricket numbers, with counts averaging 2787 ± 277 individuals, while the other five caves never exceeded 250 individuals; crickets were most abundant from late September to early November. Behavioral observations and pitfall trapping indicate that crickets leave caves at night and prefer walking along the outer surfaces of walls rather than over open ground and, in some cases, may inhabit large crevices on cliff facings. Crickets were not commonly found under boards, rocks, or seabird burrows on the island, although diversity and numbers of other arthropods were significantly greater under artificial board salamander refuges vs. natural ground cover and during the wetter winter and spring seasons.

Diagnostic protocols for the detection of Acheta domesticus densovirus (AdDV) in cricket frass

The European house cricket (Acheta domesticus) is a species of interest for the emerging insect-as-food industry. Acheta domesticus densovirus (AdDV) is a member of the Parvoviridae virus family which infects A. domesticus, causing widespread mortality and even extinction of local cricket populations. Despite the well-known detrimental effects of AdDV in commercial rearing of A. domesticus there are no optimized protocols to accurately and non-destructively detect and quantify the virus. This study establishes a new protocol for the detection of AdDV in faecal material from A.domesticus. The protocol includes methodological improvements, such as upgrading from conventional PCR to quantitative real-time PCR and is much more sensitive than previously published protocols. Moreover, this study shows that cricket faeces are a suitable, non-destructive sample substrate to infer reliably if a cricket population is infected with AdDV or not. Early detection of lethal or economic threats, such as disease-causing viruses, is an essential part of commercial cricket management as well as for monitoring the risk of spread to wild cricket populations or to (human) consumers.

Sex-based differences in anti-predator response of crickets to chemical cues of a mammalian predator.

Anti-predator behaviors like vigilance or hiding come at the expense of other fitness increasing behaviors such as foraging. To compensate for this trade-off, prey assess predation risk and modify the frequency of anti-predator behaviors according to the likelihood of the threat. In this study, we tested the ability of house crickets (Acheta domesticus) to indirectly assess predation risk via odors from a mammalian predator, Elliot’s short-tailed shrew (Blarina hylophaga). As natural differences in encounter rates and predation risk differs between sexes, we tested if male and female crickets perceive similar rates of predation risk from the presence of shrew odor measured via anti-predator behavioral response. Crickets were placed in enclosed, cardboard-lined chambers either treated with shrew odor or control, along with a food source. Time until foraging was measured for each individual and compared across treatment and sex. We found that in the presence of shrew odor, female crickets delayed foraging while males showed no response. These results suggest adult crickets can use chemical cues to detect mammalian predators. Furthermore, we demonstrate that female crickets associate greater predation risk from shrew predators than do male crickets, which are more stationary yet acoustically conspicuous. As predation risk potentially differs drastically for each sex, changes to the operational sex ratios of wild cricket populations could be influenced by the identity of the predator community.

Genetic identification of a non-native species introgression into wild population of the field cricket Gryllus campestris (Orthoptera: Gryllidae) in Central Europe

Two species of the genus Gryllus occur in Europe: G. campestris and G. bimaculatus. The first is widely distributed in the north-western Palaearctic, while the second, G. bimaculatus, occurs predominantly in the Mediterranean area. There is a visible pattern in the distribution of G. campestris, the insect being rare and threatened in the western part of its range, whereas it is still abundant in the east. Despite the fact that this species is commonly used in laboratory experiments, its natural populations are poorly characterised. In the present study, we analysed cricket populations from the lower Oder and Vistula River valleys in Poland. Based on the phylogeny of the mtDNA cytochrome b fragment, we found that 17% of the individuals studied had a G. bimaculatus-like mtDNA haplotype. Analyses of 11 autosomal microsatellite loci failed to reveal any clear genetic differentiation between individuals assigned to these two clades. This suggests, along with the spatial distribution of G. bimaculatus-like haplotypes, successful interbreeding of G. bimaculatus with native populations of G. campestris. However, both the nuclear data and additional analyses of two X-chromosome-linked microsatellite loci revealed incomplete introgression. Human-mediated introgression seems to be the most plausible explanation of the observed genotypic pattern such that caution needs to be taken in conservation efforts carried out in the western part of the species' range.

Genotoxicity testing for radon exposure: Dolichopoda (Orthoptera, Rhaphidophoridae) as potential bio-indicator of confined environments

Abstract Radon represents the major source of natural radioactivity in confined environments. Despite the clear evidence of a direct association between residential exposure and human lung cancer provided by case-control studies, results relating indoor exposure and genotoxic/mutagenic effect induction are still contradictory. The present study attempts to estimate the genotoxic effects induced by exposure to radioactive radon in wild cricket populations sampled from caves where varying concentrations of radon are present. Cave crickets are also tested as possible bio-indicator organisms of genotoxic potential of contaminated residential and confined environments. Six caves in Central Italy are considered covering a broad spectrum of radon radioactivity concentration (221–26, 000 Bq/m3). Dolichopoda specimens were sampled from each cave; both haemocytes and brain cells taken from individuals were tested for responsiveness to DNA damage induced by radon through the Comet assay. Specimens from the least radioactive cave, housed in controlled conditions for 60 days before analysis, were used as control group. Statistically significant increase of DNA damage was found in all groups of individuals from each cave, for both cell types. Very low values of all Comet parameters were found in control group individuals, which gave indications of a good responsiveness of the organism to the variable environmental levels of radioactive contamination. Results indicate that cave crickets represent a reliable tool for the detection of genotoxic potential induced by radioactive contamination of confined environments and can be proposed as a possible bio-indicator system for air (-radioactive) pollution related to indoor exposure.

Contrasting patterns of macroptery in Roesel’s bush cricketMetrioptera roeselii(Orthoptera, Ensifera)

We studied the wing dimorphism in Roesel's bush cricket populations. A total of 410 individuals (77 macropterous and 333 brachypterous) were sampled in seven sites. We found a high frequency (≤ 53%) of macropterous individuals in some meadows surrounded by forests. We measured the body weight, thorax weight, and abdomen weight in connection with macroptery vs brachyptery. We could find a positive correlation between macroptery and thorax weight. The abdomen weight of females showed high individual variation; thus the supposed trade-off between macroptery and lower fertility of females was not supported.

Parasite-induced Changes in the Anti-predator Behavior of a Cricket Intermediate Host

Many parasites with complex life cycles are known to modify their host phenotype to enhance transmission from the intermediate host to the definitive host. Several earlier studies explored these effects in acanthocephalan and trematode parasites, especially in aquatic ecosystems; however, much less is known about parasite-mediated alterations of host behavior in terrestrial systems involving nematodes. Here, we address this gap by investigating a trophically transmitted nematode (Pterygodermatites peromysci) that uses a camel cricket (Ceuthophilus pallidipes) as the intermediate host before transmission to the final host, the white-footed mouse (Peromyscus leucopus). In a laboratory experiment, we quantified the anti-predatory responses of the cricket intermediate host using simulated predator cues. Results showed a decrease in jumping performance among infected crickets as compared with uninfected crickets, specifically in terms of frequency of jumps and jumping distance. Additionally, the relationship between parasite load and frequency of jumps is negatively correlated with the intensity of infection. These behavioral modifications are likely to increase vulnerability to predation by the definitive host. An analysis of the age-intensity pattern of infection in natural cricket populations appears to support this hypothesis: parasites accumulate with age, peak at an intermediate age class before the intensity of infection decreases in older age groups. We suggest that older, heavily infected crickets are preferentially removed from the population by predators because of increased vulnerability. These results show that cricket intermediate hosts infected with P. peromysci have diminished jumping performance, which is likely to impair their anti-predatory behavior and potentially facilitate parasite transmission.

Responses of an island endemic invertebrate to rodent invasion and eradication

Invertebrates dominate many terrestrial ecosystems in terms of biomass, and they also structure ecosystems through their roles as pollinators, detritivores, primary consumers, predators and prey. Invasive rodents (rats and mice) are known to have detrimental effects on many island invertebrates, although these effects are seldom quantified or ecologically understood. Here we provide evidence of the effects of invasive rats (Rattus spp.) on island invertebrate populations using a large-scale natural experiment. We investigated the effects of invasive rats on Falkland camel crickets (Parudenus spp.) in the Falkland Islands (South Atlantic) by comparing an index of camel cricket relative abundance between 18 rat-infested islands, six rat-eradicated islands and 13 naturally rat-free islands (in total, 37 islands). Our study provided two key results. First, camel crickets were up to an order of magnitude more abundant on rat-free islands than on rat-infested or rat-eradicated islands. This difference was larger in native tussac grass Poa flabellata than in other vegetation types. Second, camel cricket populations recovered after rat eradication, because the relative abundance of camel crickets on rat-eradicated islands was intermediate between those of naturally rat-free and rat-infested islands, and among rat-eradicated islands relative abundance was lowest where rats had been cleared most recently. Our results demonstrate severe suppression of a superabundant and large-bodied island endemic invertebrate by invasive rodents, and its prompt recovery after rodent eradication.

Nectar-Seeking and Host-Seeking byLarra bicolor(Hymenoptera: Crabronidae), a Parasitoid ofScapteriscusMole Crickets (Orthoptera: Gryllotalpidae)

Larra bicolor F. (Hymenoptera: Crabronidae) is a specialist parasitoid of Scapteriscus (Orthoptera: Gryllotalpidae) mole crickets, attacking adults and medium to large nymphs of the hosts. Adult wasps derive energy from plant nectars. In replicated trials in pastures in northern Florida, many more wasps fed on nectar of Spermacoce verticillata F. (Rubiaceae), a non-native plant, than on nectar of the native plants Spermacoce prostrata Aubl. or Spermacoce remota Lamarck. Few of them fed on the native plant Solidago fistulosa Michx. (Asteraceae). About as many fed on the native plant Chamaecrista fasciculata (Michx) Greene as on S. verticillata in the autumn months until the native plant ceased flowering by October. In contrast, S. verticillata continues flowering until the first hard freeze, which typically occurs in December, so overall, it is a more reliable nectar source in northern Florida and may be still more reliable in frost-free areas of southern Florida where it may flower year-round. The number of immature wasps (eggs and larvae) parasitizing mole crickets was positively related to host density but also declined with distance from a plot of S. verticillata out to 200 m, based on samples of pitfall trap-collected mole crickets. The occurrence of parasitized mole crickets at a 200-m distance suggests that female wasps recruited to a plot of S. verticillata forage for hosts out to at least 200 m. This in turn suggests that mole cricket populations might be diminished by planting plots of S. verticillata at least 400 m apart when L. bicolor wasps are present.

Hearing and spatial behavior in Gryllotalpa major Saussure(Orthoptera: Gryllotalpidae)

The prairie mole cricket (Gryllotalpa major Saussure) is a rare orthopteran insect of the tallgrass prairie ecosystem of the south central USA. Populations are known to currently occupy fragmented prairie sites in Oklahoma, Arkansas, Kansas and Missouri, including The Nature Conservancy's Tallgrass Prairie Preserve in north central Oklahoma. Prairie mole cricket populations were surveyed at this site and at another site in Craig County, OK during the spring of 2005 and 2006, using the male cricket's acoustic call to locate advertising aggregations of males. Five males from one large aggregation were removed in a study to describe (1) the hearing thresholds across the call's range of frequencies, (2) the distances over which the higher harmonic components of the male's calls are potentially detectable, (3) the species' sensitivity to ultrasound and (4) the spatio-auditory dynamics of the prairie mole cricket lek. Results indicate that G. major has a bimodal pattern of frequency tuning, with hearing sensitivities greatest at the 2 kHz carrier frequency (41 dB SPL) and declining through the call's frequency range (84 dB at 10 kHz). A second sensitivity peak is evident in the ultrasound range at 25 kHz (62 dB SPL). Spatial analysis of G. major lek sites indicates that approximately 73% of males within the lek are spaced in such a way as to allow acoustic interaction at the species' carrier frequency, while any information in higher harmonic overtones in the call appears to be available only to nearest neighbors.