Predominantly Left-Dominant Mandibular Chirality In Coleoptera

Patterns of mandible chirality have been virtually unexplored in beetles, apart from a single study in 2010. Here we present the mandible chirality trends found in 58 beetle species representing the families Carabidae (52 species), Cerambycidae (three species), and Silphidae (three species) that display overlapping mandibles. Mandible chirality was not random in the groups examined, all of which exhibited a dominant trend towards left-superiority. The degree to which each taxonomic group displayed the left-superior trend differed, with tiger beetles showing the greatest dominance (99%) and longhorned beetles the weakest (71%)

Predominantly Left-Dominant Mandibular Chirality In Coleoptera

Patterns of mandible chirality have been virtually unexplored in beetles, apart from a single study in 2010. Here we present the mandible chirality trends found in 58 beetle species representing the families Carabidae (52 species), Cerambycidae (three species), and Silphidae (three species) that display overlapping mandibles. Mandible chirality was not random in the groups examined, all of which exhibited a dominant trend towards left-superiority. The degree to which each taxonomic group displayed the left-superior trend differed, with tiger beetles showing the greatest dominance (99%) and longhorned beetles the weakest (71%)

Splendid Hybrids: The Effects of a Tiger Beetle Hybrid Zone on Apparent Species Diversity

Nonexpert citizen groups are being used to monitor species to track ecosystem changes; however, challenges remain for proper identification, especially among diverse groups such as beetles. Tiger beetles, Cicindela spp., have been used for biological diversity monitoring because of their diversity and the ease of recognition. The finding of an apparent hybrid zone among Cicindela denverensis Casey, Cicindela limbalis Klug, and Cicindela splendida Hentz in central Nebraska prompted a detailed study of the biogeography of this species group within Nebraska, a test of characteristics that could be used by citizen scientists, and limited breeding experiments. This study suggests that while C. denverensis appears to hybridize with both C. limbalis and C. splendida within the hybrid zone, all three species maintain their integrity across most of their ranges, largely occupy unique geographic regions, and at least C. denverensis and C. splendida cooccur in many areas with no evidence of hybridization. Evidence of hybridization between C. limbalis and C. splendida was found at only two sites. Furthermore, breeding experiments with virgin C. splendida and C. denverensis showed that they are capable of producing hybrid larvae in the laboratory. The presence of morphological intergrades serves as a cautionary note when using biological indicator species

Splendid Hybrids: The Effects of a Tiger Beetle Hybrid Zone on Apparent Species Diversity

Nonexpert citizen groups are being used to monitor species to track ecosystem changes; however, challenges remain for proper identification, especially among diverse groups such as beetles. Tiger beetles, Cicindela spp., have been used for biological diversity monitoring because of their diversity and the ease of recognition. The finding of an apparent hybrid zone among Cicindela denverensis Casey, Cicindela limbalis Klug, and Cicindela splendida Hentz in central Nebraska prompted a detailed study of the biogeography of this species group within Nebraska, a test of characteristics that could be used by citizen scientists, and limited breeding experiments. This study suggests that while C. denverensis appears to hybridize with both C. limbalis and C. splendida within the hybrid zone, all three species maintain their integrity across most of their ranges, largely occupy unique geographic regions, and at least C. denverensis and C. splendida cooccur in many areas with no evidence of hybridization. Evidence of hybridization between C. limbalis and C. splendida was found at only two sites. Furthermore, breeding experiments with virgin C. splendida and C. denverensis showed that they are capable of producing hybrid larvae in the laboratory. The presence of morphological intergrades serves as a cautionary note when using biological indicator species

NEW RECORDS OF CARRION BEETLES IN NEBRASKA REVEAL INCREASED PRESENCE OF THE AMERICAN BURYING BEETLE, NICROPHORUS AMERICANUS OLIVIER (COLEOPTERA: SILPHIDAE)

Surveys for the American burying beetle, Nicrophorus americanus Olivier (Silphidae), between 2001 and 2010 in Nebraska resulted in 11 new county records for this endangered species and 465 new county records for 14 other silphid species. A total of 5,212 American burying beetles were captured in more than 1,500 different locations. Using mark-recapture data, we estimated the population size of the American burying beetle (ABB) for six counties in the Sandhills. Blaine County (2003) had the largest population, with an estimated 56 ABBs per km2 (1,338 ± 272 ABBs). The remaining estimates were between 2 and 36 ABBs per km2, which were calculated for Loup (2010) and Holt (2010) Counties, respectively. We calculated movement distances, finding that some American burying beetles moved as far as 7.24 km in a single night. This new information greatly contributes to efforts to conserve the American burying beetle in the Great Plains and provides knowledge about other silphid species distributions, which may play a role in recovery of the American burying beetle

NEW RECORDS OF CARRION BEETLES IN NEBRASKA REVEAL INCREASED PRESENCE OF THE AMERICAN BURYING BEETLE, NICROPHORUS AMERICANUS OLIVIER (COLEOPTERA: SILPHIDAE)

Surveys for the American burying beetle, Nicrophorus americanus Olivier (Silphidae), between 2001 and 2010 in Nebraska resulted in 11 new county records for this endangered species and 465 new county records for 14 other silphid species. A total of 5,212 American burying beetles were captured in more than 1,500 different locations. Using mark-recapture data, we estimated the population size of the American burying beetle (ABB) for six counties in the Sandhills. Blaine County (2003) had the largest population, with an estimated 56 ABBs per km2 (1,338 ± 272 ABBs). The remaining estimates were between 2 and 36 ABBs per km2, which were calculated for Loup (2010) and Holt (2010) Counties, respectively. We calculated movement distances, finding that some American burying beetles moved as far as 7.24 km in a single night. This new information greatly contributes to efforts to conserve the American burying beetle in the Great Plains and provides knowledge about other silphid species distributions, which may play a role in recovery of the American burying beetle

Movement of \u3ci\u3eCicindela hirticollis\u3c/i\u3e Say Larvae in Response to Moisture and Flooding

The larvae of the tiger beetle, Cicindela hirticollis Say, inhabit sandy shoreline areas that flood periodically. This species has declined over much of its range and at least one subspecies is near extinction, possibly as a result of human alteration of waterways. In addition to physiological tolerance for anoxia, the larvae have physical and behavioral adaptations to avoid drowning. We hypothesized that C. hirticollis larvae would exhibit behavioral responses to soil moisture change and flooding because, unlike most other tiger beetles, they frequently relocate their burrows. Our laboratory studies demonstrated that larvae select surface soil moisture levels of 7–50% saturation in which to dig new burrows. Within 96 h of immersion, most larvae abandon burrows and larvae do not form new burrows in darkness. Larvae may relocate when flooded, suggesting a previously undocumented mechanism for dispersal; however, dams often eliminate suitable habitat areas downstream, suggesting that this behavior may be detrimental in riverine populations. Because larvae move during daylight hours, they also are likely to suffer mortality from trampling due to human recreational activity

Movement of \u3ci\u3eCicindela hirticollis\u3c/i\u3e Say Larvae in Response to Moisture and Flooding

The larvae of the tiger beetle, Cicindela hirticollis Say, inhabit sandy shoreline areas that flood periodically. This species has declined over much of its range and at least one subspecies is near extinction, possibly as a result of human alteration of waterways. In addition to physiological tolerance for anoxia, the larvae have physical and behavioral adaptations to avoid drowning. We hypothesized that C. hirticollis larvae would exhibit behavioral responses to soil moisture change and flooding because, unlike most other tiger beetles, they frequently relocate their burrows. Our laboratory studies demonstrated that larvae select surface soil moisture levels of 7–50% saturation in which to dig new burrows. Within 96 h of immersion, most larvae abandon burrows and larvae do not form new burrows in darkness. Larvae may relocate when flooded, suggesting a previously undocumented mechanism for dispersal; however, dams often eliminate suitable habitat areas downstream, suggesting that this behavior may be detrimental in riverine populations. Because larvae move during daylight hours, they also are likely to suffer mortality from trampling due to human recreational activity

Short-horned grasshopper subfamilies feed at different rates on big bluestem and switchgrass cultivars

Grasshopper species belonging to subfamilies Melanoplinae, Gomphocerinae and Oedipodinae were tested for their feeding rate on three types of grass. All grasshopper species were offered Shawnee and Kanlow cultivars of switchgrass, Panicum virgatum L. and big bluestem, Andropogon gerardii Vitman. The grasshoppers, Melanoplus femurrubrum and Melanoplus differentialis were also tested for their feeding on turgid or wilted leaves of the Shawnee cultivar of switchgrass. We found that M. differentialis consumed more switchgrass compared to big bluestem while M. femurrubrum and Arphia xanthoptera consumed the most Shawnee switchgrass. The M. differentialis consumed more turgid grass compared to wilted switchgrass. The feeding performances show differences among grasshopper species even in the same subfamily and suggest that Melanoplinae grasshoppers may become destructive pests of switchgrass planted for biofuel production.

Morphological and genetic analyses in the Melanoplus packardii group (Orthoptera: Acrididae)

Melanoplus packardii Scudder was described in 1897. Three additional closely-related species were later described and their status as species has been questioned on numerous occasions. We examined morphology from specimens collected in Nebraska which fit descriptions of three of the four forms and specimens that appeared to be hybrids. We found distinct morphological characters suggesting species status for M. foedus and M. packardii, but not for M. foedus fluviatilis. Examination of aedeagi of these three forms suggests that M. foedus and M. packardii are each distinct, but that the aedeagi of M. f. fluviatilis and M. f. foedus cannot be distinguished. Molecular analyses of the three groups did not produce clear separations and suggest gene exchange between these three forms may be ongoing. Together, these data suggest that M. foedus and M. packardii should be recognized as sibling species, but M. foedus fluviatilis is best considered a form of M. foedus, typically found in low lying areas