Stoneflies (Plecoptera) in South Africa are limited to cool pristine mountain streams. This provides them with very limited habitat in which to survive. The species of stonefly studied in this project (Aphanicercella cassida) has a very wide distribution unlike most other species which have a limited range. Of particular interest is a population in Mpumalanga (north of South Africa) which is very disjunct from the other populations of A. cassida found widely in the southwestern Cape. Despite this large geographic distance the insects appear to be morphologically identical to one another. It is believed that there is limited or no gene flow between the northern and southern populations as stoneflies are poor fliers. Molecular analysis of the cytochrome oxidase I gene in the mitochondrial DNA was analysed to see if any genetic differentiation was occurring inspite of the morphological homogeneity. A 557 base pair region was compared across three populations of A. cassida one in Mpumalanga and two in the southwestern Cape. Two congeneric species, A. bullata and A. scutata, were used as outgroups. The findings of this study were quite dramatic. The northern population is extremely different from the southern populations at the molecular level. There is more variation between the two populations of A. cassida than between the two outgroup species and the split between the two disjunct populations displays evidence of an ancient vicariance event. This finding definitely warrants further investigation into whether the population of A. cassida in Mpumalanga is a cryptic species. More sampling has to be done within the studied populations and more populations should be added to the analysis before any definite decision can be made regarding this fascinating emergence of possible cryptic species in South African stoneflies.

Collections of stoneflies (Plecoptera) were made at 603 stream sites from Nov. 1983 - May 1988 in the Ozark-Ouachita Mountain region, in relation to physiographic and vegetational characteristics. Examination of approximately 9000 vials from these collections, supplemented with material from major museums and other collectors, revealed 88 stonefly species in 8 families and 24 genera. Pearson's measure of association (R) showed there was a significant association between species present and each of the tested variables.

Thesis (M.S.)--University of Wisconsin, 1972. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 60-62).

An illustrated key to the adults and known nymphs of Texas Plecoptera is provided. Species accounts, including geographic distribution within Texas, and biological notes are given. Of the twenty-seven species of Plecoptera known from Texas, six are new state records. TWo species new to science, Isoperla jewetti and Isoperla coushatta are described. Taeniopteryx starki Stewart and Szczytko, Zealeuctra arnoldi Ricker and Ross, and Zealeuctra hitei Ricker and Ross are endemic to the Edwards Plateau area of Texas. Two species, Mesocapnia frisoni (Baumam and Gaufin) and Isoperla jewetti New Species are western in origin. The remaining nineteen species (excluding Anacroneuria) are typically eastern species.

No description available.

El presente estudio fue realizado con el objetivo de conocer la composición y distribución espacial y temporal de la comunidad de Ephemeroptera, Plecoptera, Trichoptera y Coleoptera (EPTC) en una quebrada de primer orden, Chanchamayo, Perú. Se realizaron colectas bimensuales desde marzo del 2013 a enero del 2014 en cuatro microhábitats lóticos: piedra, grava, musgo y hojas retenidas en la corriente. Fueron colectados un total de 7825 individuos agrupados en 51 géneros distribuidas en 27 familias de EPTC. La mayor riqueza y abundancia fue registrada en las hojas retenidas en la corriente y durante los meses de julio y setiembre (menor caudal). Las pruebas no paramétricas de Kruskall-Wallis para la riqueza, abundancia y estructura comunitaria (diversidad de Shannon-Wiener y equidad de Pielou) determinaron diferencias significativas (p<0.05) a nivel espacial y temporal; en tanto que el análisis de similitud (ANOSIM) y de agrupamiento utilizando el método no paramétrico de escalamiento multidimensional (nMDS) determinaron diferencias significativas a nivel espacial pero no a nivel temporal. La variación espacial estuvo explicada por la heterogeneidad del hábitat; y la variación temporal se explicó principalmente por la hidrología del ecosistema. El factor espacial predominó sobre el temporal para determinar la estructura de la comunidad de EPTC. Además el análisis de similitud porcentual (SIMPER) permitió identificar las especies que más influyeron en la estructura comunitaria de EPTC. La quebrada Pichita fue calificada como de referencia por el “Riparian, Chanel and Enviromental Inventory” (RCE) y el Protocolo de la Calidad Ecológica de los Ríos Andinos (CERA).

Distributional data and taxonomic keys art presented for thirty-four species of Plecoptera known to occur in Oklahoma. Ten species are new records for the state. Descriptions are provided for two species new to science, Zealeuctra cherokee and Isoperla brevis, and for the previously unknown male of Strophopteryx cucullata Frison and female of Helopicus nalatus (Frison).

Species inhabiting intermittent streams must have life-history traits that confer resistance or resilience to flow cessation or drying. However, we lack basic life-history information for most aquatic invertebrate species, especially those from intermittent streams. I documented the life cycle and distribution of an unusual winter stonefly species, Mesocapnia arizonensis (Capniidae). The species was first described from 6 localities in 1969, but its natural history remained enigmatic. I surveyed >90 streams across the southwestern USA, documented the life cycle of M. arizonensis at 1 locality, and experimentally rehydrated dry streambed sediment in search of dormant stoneflies at another locality. Field surveys expanded the number of localities from 22 to 98, most of which were intermittent with flow durations as brief as 3 mo/y, and extended the known range of the species by 800 km. Nymphs were abundant within days of flow resumption, grew rapidly as a single cohort, and started emerging as adults 42 d after flow resumed. The brief appearance of a 2(nd) cohort of tiny nymphs 1 mo before the stream dried indicates direct hatching of at least some eggs. I failed to find dormant stoneflies in the top 30 cm of dry stream sediment, suggesting that M. arizonensis undergoes dormancy deep in the substrate, putting it safely out of reach of scouring summer floods that occur between favorable winter seasons. The remarkable ability of M. arizonensis to survive in short-flow duration streams and to endure multiple consecutive dry years, suggests that the species is well prepared for the drier climatic conditions predicted to occur across its range.

Freshwater ecosystems in south-western Australia have been extensively altered over the last two centuries as a result of human activities. The effect this has had on aquatic fauna, particularly invertebrates, is largely unknown because of inadequate knowledge of the pre-existing fauna. Future changes in the composition of aquatic fauna will also go undetected unless current distributions of existing species are well documented. This thesis addresses the problem by investigating the current distributions and conservation status of aquatic insects in south-western Australia from three orders: Odonata, Plecoptera and Trichoptera. Extensive distributional data was collected by identifying larval specimens from a large number of samples collected throughout the south-west as part of an Australia-wide macroinvertebrate bioassessment project. In addition, a database created from a species-level biological study of the wheatbelt region of Western Australia was utilised, and previously published records of occurrence for species within the south-west were compiled. These results were then used to assess the conservation status of each species using the IUCN red list criteria. Environmental parameters measured at time of sampling were also examined using logistic regression to determine which factors are important in influencing the distributions of aquatic insects in south-western Australia. The conservation value of sites based on Odonata, Plecoptera and Trichoptera compositions was also determined and the degree of protection provided for sites of high conservation value investigated.The high rainfall forested region of the south-west was found to be important for a large number of species, including the majority of those found to be rare and/or restricted. Overall, 37% of species were found to be threatened, with the Trichoptera containing both the greatest number and highest proportion of threatened species. Logistic regression results generally agreed with the distributions obtained for each species, with rainfall and other parameters indicative of streams in the headwaters of forested catchments being positively associated with species found to be restricted to the high rainfall region. Two parameters known to be affected by human disturbance in the south-west, conductivity and nutrient concentrations, were found to be important in determining the occurrence of many species and this could have important consequences for aquatic insect conservation. Widespread species occurring within the low rainfall region of the south-west did not show as many significant relationships to measured environmental parameters, possibly due to their greater ecological tolerances and adaptations which allow them to persist in a low rainfall environment. The implications of results are discussed, and recommendations for the conservation and management of aquatic insects in south-western Australia are given.

The stonefly genus Isogenoides is revised following a holomorphological approach utilizing traditional morphology and behavioral lines of evidence. Species keys are provided for all life stages. One species, I. krumholzi (Ricker) is considered a synonym of I. doratus (Frison). Detailed species descriptions are provided for males, females, nymphs and ova. Distributions are updated utilizing all known published accounts and materials examined. The vibrational communication (drumming) behavior is reported for males and all but one species for females. The signals were species-specific and ranged in complexity from ancestral sequenced duets to derived grouped exchanges. I. olivaceus is least specialized, having mostly sequenced duets, and I. zionensis most specialized, displaying ancestral sequenced, derived grouped and complex derived exchanges containing both sequenced and grouped elements. Laboratory egg incubation experiments over a 2-4 year period show that Isogenoides has a great capacity for extended, sometimes-asynchronous diapause and hatching. The eggs of six species were incubated at a single, ca. simulated San Miguel River, Colorado, seasonal temperature regime. Direct hatch within two weeks occurred only for I. zionensis (Leopard Creek, Colorado) with small numbers hatching again after one, two, and four years. Eggs of I. doratus and I. varians hatched after an over summer, 3-5 month diapause, and I. varians again in August the next year. Populations of I. colubrinus, I. elongatus, I. frontalis and San Miguel River, I. zionensis began hatching after a 9-11 month diapause and again during spring-summer temperatures in 2nd through 4th years. I. zionensis in the San Miguel River, Colorado, exhibited a semivoltine life cycle over the two-year study period. Adults emerged in June-July when stream temperature reached ca. 11-17°C. Reared females at Quartz Creek, Pitkin, Colorado, deposited up to three egg batches. Mean fecundity of females was 691 egg/female. Oviposition in the field was observed and described. Nymphal growth was exponential from June to December, followed by slow growth until April, then declined until emergence. The greatest growth occurred between July and December as stream temperature decreased to minimum and maximum size was obtained in March while stream temperature began to increase.