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Densities of Orthoptera typically vary greatly over space and time. The most important salt marsh orthopteran on the East Coast of the US is Orchelimum fidicinium, an omnivore that feeds on cordgrass (Spartina alterniflora) and arthropods. We examined spatial (34 sites) and temporal (5 sites, 17 years) variation in O. fidicinium density in coastal Georgia. Sites with considerable adjacent upland habitat had higher densities of O. fidicinium than sites with little adjacent upland. Grasshoppers fed S. alterniflora from both types of sites did not differ in growth rates, ruling out food quality as an explanation. We speculate instead that O. fidicinium require terrestrial habitat for reproduction or escape from predators during extreme high tides. At five sites where O. fidicinium was common, densities varied greatly among years. Regression models indicated that current year plant biomass (three sites) or previous year plant biomass (one site) was the best predictor of O. fidicinium density. Relationships between O. fidicinium and current year plant biomass were typically negative (more grasshoppers in years with lower plant biomass). A possible explanation for this pattern is that plant nutrients may be diluted in years with high plant biomass. We found little evidence that density of animal prey (Prokelisia spp.) or abiotic factors affected O. fidicinium densities. Our study illustrates the value of examining population densities across multiple sites and years, because results from any one site or year would likely have mischaracterized the spatial and temporal distribution of this common salt marsh consumer.

Insect gut microbiomes consist of bacteria, fungi, and viruses that can act as mutualists to influence the health and fitness of their hosts. While much has been done to increase understanding of the effects of environmental factors that drive insect ecology, there is less understanding of the effects of environmental factors on these gut microbial communities. For example, the effect of environmental nutrients on most insect gut microbiomes is poorly defined. To address this knowledge gap, we investigated the relationship between environmental nutrients and the gut microbial communities in a small study of katydids (n = 13) of the orthopteran species Orchelimum vulgare collected from a costal prairie system. We sampled O. vulgare from unfertilized plots, as well as from plots fertilized with added nitrogen and phosphorus or sodium separately and in combination. We found significantly higher Shannon diversity for the gut bacterial communities in O. vulgare from plots fertilized with added sodium as compared to those collected from plots without added sodium. In contrast, diversity was significantly lower in the gut fungal communities of grasshoppers collected from plots with added nitrogen and phosphorus, as well as those with added sodium, in comparison to those with no added nutrients. There was also a strong positive correlation between the gut bacterial and gut fungal community diversity within each sample. Indicator group analysis for added sodium plots included several taxa with known salt-tolerant bacterial and fungal representatives. Therefore, despite the small sample number, these results highlight the potential for the gut bacterial and fungal constituents to respond differently to changes in environmental nutrient levels. Future studies with a larger sample size will help identify mechanistic determinants driving these changes. Based on our findings and the potential contribution of gut microbes to insect fitness and function, consideration of abiotic factors like soil nutrients along with characteristic gut microbial groups is necessary for better understanding and conservation of this important insect herbivore.

The meadow katydid Orchelimum superbum was previously known from scattered localities along the Atlantic and Gulf Coasts of North America. We found this species to be widespread and locally common on the Great Plains in a variety of habitats, including tallgrass prairie, wetlands, and roadsides. We found no evidence for cryptic species after studying the morphology of the male terminalia, comparing body size, and analyzing 14 calling song characters. Individuals from the Great Plains are consistently larger in body size than individuals from the historical range. From patterns of body size variation and abundance, we hypothesize that the eastern Great Plains is the center of distribution for O. superbum and that the coastal localities, including the type locality, are peripheral populations. We compare the songs of O. superbum and O. vulgare, showing that these two sympatric but allochronically separated species share most buzz-mode characters including statistically indistinguishable syllable re...

Top–down and bottom–up effects interact to structure communities, especially in salt marshes, which contain strong gradients in bottom–up drivers such as salinity and nutrients. How omnivorous consumers respond to variation in prey availability and plant quality is poorly understood. We used a mesocosm experiment to examine how salinity, nutrients, an omnivore (the katydid Orchelimum fidicinium) and an herbivore (the planthopper Prokelisia spp.) interacted to structure a simplified salt marsh food web based on the marsh grass Spartina alterniflora. Bottom–up effects were strong, with both salinity and nutrients decreasing leaf C/N and increasing Prokelisia abundance. Top–down effects on plants were also strong, with both the herbivore and the omnivore affecting S. alterniflora traits and growth, especially when nutrients or salt were added. In contrast, top–down control by Orchelimum of Prokelisia was independent of bottom–up conditions. Orchelimum grew best on a diet containing both Spartina and Prokelisia, and in contrast to a sympatric omnivorous crab, did not shift to an animal-based diet when prey were present, suggesting that it is constrained to consume a mixed diet. These results suggest that the trophic effects of omnivores depend on omnivore behavior, dietary constraints, and ability to suppress lower trophic levels, and that omnivorous katydids may play a previously unrecognized role in salt marsh food webs.

Although grasshoppers are common salt marsh herbivores, we know little about geographic variation in their species composition. We documented latitudinal variation in species composition of the tettigoniid grasshopper fauna of Atlantic Coast salt marshes. Tettigoniids (N = 740 adults) were collected from the Spartina alterniflora zone of 31 salt marsh sites across a latitudinal range of 13.19° (Florida to Maine), with an additional 52 individuals collected from the Juncus roemerianus zone of low-latitude marshes for comparative purposes. Eight species were collected, but some were common only at a few sites or rare throughout the entire collection range. The tettigoniid community was dominated by Orchelimum fidicinium at low latitudes and Conocephalus spartinae at high latitudes. Several factors might explain this shift, including changes in climate, plant phenology, and plant zonation patterns. O. fidicinium and C. spartinae increased in body size toward low latitudes. In laboratory feeding assays, O. fidicinium readily ate S. alterniflora and J. roemerianus leaves, Orchelimum concinnum, which is largely restricted to the J. roemerianus zone, ate only J. roemerianus leaves, and Conocephalus spp. ate neither, consistent with literature suggestions that they mainly consume seeds and flowers. Geographic variation in species composition and body size of grasshoppers may help explain documented patterns of geographic variation in plant palatability and plant–herbivore interactions in Atlantic Coast salt marshes. Because it can be difficult to identify tettigoniids to species, we present a guide to aid future workers in identifying the tettigoniid species common in these marshes.

Hard-bodied orthopteran adults, in particular Acrididae, are an important source of insect contaminants in mechanically harvested leafy greens, Brassica spp. Because contaminants are usually detected after greens are fully processed, rejection of these value-added loads can be economically severe. A survey was conducted to determine the level of orthopteran species occurring in and around leafy greens fields prior to mechanical harvesting. This survey demonstrated that the vast majority of individual Orthoptera occurred around the edges of the field prior to harvest. In the second year of the survey, growers were already applying Sevin XLR™ (Aventis CropScience, Research Trangle Park, NC) insecticide to grassy border areas in order to prevent acridid adults from moving into the field before harvest. The main taxonomic groups in Orthoptera found in this survey included Orchelimum sp. (Tettigonidae) (68.8%), Melanoplinae (Acrididae) (18.5%), other Acrididae (5.4%), Schistocerca americana (Drury) (Acrididae) (3.4%), Dissosteira Carolina (Linnaeus) (Acrididae) (2.4%), and other Tettigonidae (1.6%). Insecticide treatment of border areas prior to harvest provided a 94% reduction in Acrididae in the field prior to harvest.

The katydids Orchelimum nigripes and O. pulchellum (Orthoptera: Tettigoniidae) have a largely allopatric distribution in the eastern United States, but hybridization between these species has been well documented in two contact zones. I used animals from populations just outside a narrow, recently formed upstream-downstream hybrid zone along the Potomac River near Washington, D.C., in laboratory mate-choice trials to examine the possible importance of differential patterns of mate preference in determining the structure and dynamics of this hybrid zone. Offered a choice between a male of each species, O. nigripes females showed an extreme preference for conspecific mates, but O. pulchellum females showed no clear preference. This asymmetry in mate discrimination may contribute to the apparently ongoing replacement along the Potomac of O. pulchellum by O. nigripes in the wake of a moving hybrid zone.

A terminology useful in describing conocephaline amplitude modulation patterns is presented in this first part of a three-part study of calling songs inOrchelimummeadow katydids. Geographical distributions are mapped for the 18 species which occur in North America north of Mexico and several substantial range extensions reported, Comparison of stridulatory files indicates two types within the genus, one characterized by more widely spaced teeth near the basal end of the file. Teeth are asymmetrical in accordance with the generation of the loudest song components on wing closure.

1. Male calling songs of 10 species ofOrchelimum were tape-recorded 9 to 52 times over ranges of ambient temperatures as great as 20 °C. 2. For each species the relation between wingstroke rate and temperature was approximately linear. Calculated regression lines had coefficients of determination (r2) between 0.76 and 0.99 (aver.r2=0.93). The slopes of the regression lines varied from 0.9 to 5.1, but when extrapolated downward toŷ=0, the lines tended to converge at 11 °C (x±SD=10.9±1.9). 3. These results are similar to those published for 27 species of crickets and known for 20 additional species of katydids. 4. In previous studies, by others, the effects of temperature on rates within poikilotherm nervous systems have generally been reported asQ10 values. Such values are appropriate if rates approximate an exponential function of temperature. However, reanalysis of 15 published data sets that were adequate to justify a comparison showed that 13 fit a linear model more closely than an exponential one. Furthermore, if one half a data set was used to predict the other half, the linear model was superior to the exponential model 26 of 30 times. The temperature ranges of the 15 data sets were as small as 12 and great as 26 Celsius degrees. 5. For those 13 data sets with anr2>0.90, the regression lines tended to converge like those of katydids and crickets. For seven species of electric fish the values ofx whenŷ (discharge rate)=0 clustered about 4 °C (x±SD=4.0±1.8 C). 6. Empirically the linear model is superior to the exponential one in (1) goodness of fit, (2) prediction of effects beyond the temperature range studied, and (3) prediction of data sets from a single or no datum. 7. The origin and slope of the linear regression are generally more useful thanQ10 values as short-hand expressions of temperature effects on rates in poikilotherm nervous systems. 8. Rates in poikilotherm nervous systems are more complex in their determinants than are rates ofin vitro chemical reactions. It is therefore not surprising that the former rates fail to show the simple exponential relations to temperature that the latter show. On the other hand, that poikilotherm nervous systems should generally have approximately linear relations to temperature and that the extrapolations of linear regression lines should tend to converge at zero rate are unexpected and reveal a need for more study of underlying causes.

Discovery of the "lost types" of Xiphidium glaberrimum Burmeister, 1838, has made possible the clarification of use of several names which have been used for two species of Orchelimum. O. glaberrimum is shown to be the senior synonym for the species known as O. vulgare Harris, 1841. To preserve stability, an application has been made to the International Commission on Zoological Nomenclature to suppress both glaberrimum Burmeister and cuticulare Audinet-Serville, 1838. O. erythrocephalum Davis, 1905, is removed from synonymy with O. glaberrimum, and is the valid name for that species. Characters for distinguishing vulgare and erythrocephalum are discussed and illustrated. Type specimens are designated for glaberrimum, cuticulare, and vulgare.

Orchelimum Vulgare Harris, not hitherto reported as destructive to raspberry, did much damage by ovipositing in canes of Illinois plantations adjoining crops of clover, cowpeas and alfalfa in 1928 and 1929. Egg-laying scars, oviposition, hatching, and molting are described. Cultural and mechanical control measures are suggested. An egg parasite is recorded.

During the past four years the writer has been getting together a collection of Locustidæ from various parts of the State of Indiana, with a view a preparing a general descriptive paper of the species of that family found in the State. In working over the material thus gathered thirty-seven species are found to be represented, four of which are evidently new to science. Of the four, three belong to the genus Orchelimum and one to the genus Conocephalus. The former genus is represented in the collection by ten specis and the latter by four. Below is given a descritption of each of the four species believed to be new, together with such notes concerning the distribution of each as I find in my field note-book.

It seems quite certain in considering Redtenbacher' description of Xiphidium agile, DeGeer, which he considers the same as Orchelimum vulgare, Harris, that he took for his type of the species what is generally identified as O. vulgare. His figure (80) is also a typical vulgare. He says the elytra not at all or scarcely exceeding the hind femora, very little shorter than or equalling the wings. All the femora unarmed. These are charactes of O. vulgare, Harris.

The following table made as simple as possible, and based almost exclusively upon the female sex, will serve to distinguish the species of Xiphidium hitherto described or recorded from the United States and Canada. It included only the species of Xiphidium proper; i. e., those of slender form with straight or nearly straight ovipositor, excluding the stouter species with distinctly arcuate ovipositor, commonly referred to Orchelimum, though both are classed together by Redtenbacher.

Orchelimum carinatum, known from western Tennessee and western Florida, is easily distinguished from other Orchelimum by morphology and by calling song. O. pulchellum Davis, O. nigripes Scudder, O. bullatum Rehn and Hebard, and O. carinatum constitute the nigripes group of Orchelimum.

Those who visit the pine-barrens of New Jersey know what a pleasure it is to ramble along the narrow wooded-ppaths among the pine trees ; old paths that after once being made continue for many years, and may seldom entertain a pedestrian. Along these paths and by the side of the sandy roads, any time during late summer arrd until frost, one may hear a faint, lisping little song from a grasshopper corning from the pines, often from their topmost branches. It is an easy matter to climb the pitch-pine, which is usually arranged admirably for the purpose, and the grasshopper is also friendly to investigation, and commonly continues to stridulate.