Species Of Isoperla Research Articles

A new stonefly species (Plecoptera: Perlodidae) from Eocene Baltic amber and questions on the wing venation potential for species diagnostic of fossil Plecoptera

Examination of Baltic amber Plecoptera reveals a new species of Isoperla: Isoperla baltica sp. nov. The placement of this new species is supported by an in-depth comparison of apomorphies supporting families, subfamilies, and suborders. Contrary to previous descriptions of many fossil species, we took advantage of the good preservation of the genitalia to describe and compare this new species to its extant congeners. Finally, we discuss the usefulness and limitations of relying on wing venation to identify diagnostic characters in Plecoptera by figuring a specimen of Pteroliriope sinitshenkovae Cui, Béthoux, Kondratieff, Shih & Ren, 2016 with numerous crossveins and an original organization of forewing veins.

A New Species of Isoperla (Plecoptera: Perlodidae) from the Southern Carpathians, and Further Contributions to the Fauna of the Ţarcu Mts

Isoperla nagyi sp. n. is described on the basis of morphology of male and female adults and eggs. The new species is classified as an isolated species within the West Palaearctic Isoperla. It was found in the lower elevations of the Ţarcu Mts that is forming a high range of the westernmost Southern Carpathians. Further contributions are given on the stonefly fauna of the Ţarcu Mts, including notes on the Romanian distribution of Brachyptera bulgarica Raušer, and the taxonomy and distribution of Isoperla pusilla (Klapálek).

A new remarkable Isoperla species with abdominal processes from Hubei Province of Central China (Plecoptera: Perlodidae).

A remarkable new species of Isoperla Banks, 1906, I. sextuberculata Huo Du, sp. nov. from Hubei Province, Central China is described. The new species is distinguished by the unique paired abdominal processes on male terga 4, 7, and 8. The new species is compared to similar Isoperlinae congeners.

A new species of Isoperla (Plecoptera: Perlodidae) from the Qinling Mountains of northwestern China and notes on the Chinese species of the genus.

A new species of the perlodid genus Isoperla Banks, 1906, Isoperla qinlinga Chen, sp. nov. from Shaanxi Province of northwestern China is described. The new species is characterized by the mostly dark head and pronotum, the poorly developed vesicle, the modified ventral and dorsal aedeagal lobes, and the slightly developed, rounded subgenital plate of the female. Comments are provided on the known species of Isoperla of China.

Isoperla vjosae sp. n., a new species of the Isoperla tripartita group from Albania (Plecoptera: Perlodidae).

In this contribution, we describe Isoperla vjosae sp. nov. from Albania. We characterize males, females, and larvae of the new species collected at the Vjosa River using morphological and molecular approaches. Isoperla vjosae sp.nov. is a member of the I. tripartita group, which is widely distributed in the Balkans. This new endemic species is being threatened by a proposed hydroelectric power dam on the Vjosa River impacting the type locality - a large, shifting gravel, low altitude River - an atypical habitat for larvae of the I. tripartita group. For the first time we use molecular tools to delineate Isoperla species from the Balkans.

A new species of Isoperla Banks (Plecoptera: Perlodidae) from the northeast of the Russian Far East

A new species of Isoperla, I. chereshnevi, is described from the Lankovaya River, Ola River Basin, on the northern coast of the Sea of Okhotsk, northeast of the Russian Far East. The new species description is based on details of the male aedeagus, paraprocts, vesicle, general body coloration, female subgenital plate, and larvae.

A new species of Isoperla (Insecta, Plecoptera) from the Karawanken, with considerations on the Southern Limestone Alps as centers of endemism.

A new species of the genus Isoperla (Plecoptera, Perlodidae), belonging to the oxylepis species-group is described, and the male mating call is characterized. Its range falls within a small region of the Southern Limestone Alps which is well known to be one endemism-centre of aquatic insects.

The Drumming of Isoperla pallida Aubert and Guadalgenus franzi (Aubert) (Plecoptera, Perlodidae), and Review and Evolutionary Considerations of Southern Iberian Peninsula Perlodidae

The drumming calls of two perlodid species from Southern Spain (Sierra Morena, Jaén) are analyzed and described. Nineteen calls from one male of Guadalgenus franzi were recorded, showing a simple call pattern composed of two beats with an average duration between them of 184.32 msec (range: 165-227). This is the simplest call pattern yet discovered in the Plecoptera. The female of this species also presented a simple call consisting of only one beat. The male of Isoperla pallida showed an ancestral call pattern, more simple than the other Iberian Isoperla species (I. grammatica, I. nevada or I. curtata, all of them with multiphasic drumming calls or I. bipartita with a notably different model consisting of rubbing). Calls from six different males (the female did not drum) consisted of an average of 65.94 beats (range: 25-83) with a duration average of 1462.69 msec (range: 548-1835), regularly repeated with intervals with a duration average of 22.27 msec (range: 17-30). With this study, the vibrational calls of all the Perlodid species from the Southern Iberian Peninsula, except Perlodes microcephalus and Besdolus bicolor, are known. Moreover, it presents the first record and description of the call of the monospecific genus Guadalgenus. An evolutionary approach to the vibrational communication diversification in the perlodids of the Southern Iberian Peninsula is presented, showing a complexity graduation from the more simple drumming calls (shown by Hemimelaena flaviventris and G. franzi) to the rubbing call of I. bipartita and intermediate drumming calls of other Isoperla species, consistent with the drumming evolution paradigm of Stewart (2001).

Male calling, mating and oviposition in Isoperla curtata (Plecoptera: Perlodidae)

The reproductive biology (drumming call, mating behaviour, fecundity and egg structure) of Isoperla curtata, an endemic species from the Southern Iberian Peninsula, is described. The male's mating call has a diphasic pattern, with a mean of 17.3 beats per call (range = 8-27; SD = 4.7) and a duration of 792.9 ms per call (range = 228-1312; SD = 307.9). This call differs from that of other species of Isoperla in having two distinct phases with different millisecond intervals, and is species-specific. Mating lasts between 131 and 3864 seconds (mean = 2180.9 s and SD = 1027.8). Since males and females mate more than once (mean number of matings per female was 1.85 and per male 2.25), the species is polyandric and polygynic. The position adopted by the male during mating is different from that described for other stonefly species. Other mating behaviours are interpreted as displacement manoeuvers, tactile stimulation and possibly sexual selection by cryptic female choice. There was a statistically significant correlation between size and the number of matings in females (r = 0.849; p = 0.016), but not in males. Each female laid between one to four egg masses composed of an average of 88.7 eggs. Maximum fecundity was 319 eggs. The mean egg volume was 80.5 × 105 µm3 which is very similar to that of other Isoperla species. An outstanding morphological characteristic of the egg is the lobed outline of the chorion cells.

The diet of two species of Isoperla (Plecoptera: Perlodidae) in relation to season, site, and sympatry

The seasonal change in gut contents of nymphs of Isoperla grammatica and I. difformis from six streams in southern Sweden was analysed. Both species had ingested a variety of benthic prey and vegetable matter, predominantly diatoms. Some seasonality was evident with high percentages of diatoms in spring in I. grammatica, and in autumn in I. difformis. The scope of food was larger in the latter species which contained about equal proportions of vegetable matter, chironomids, mayfly, stonefly, and black fly larvae. In I. grammatica plant matter and chironomids dominated strongly, comprising > 50% of the gut contents on an annual basis, > 90 % in spring. While small nymphs of I. difformis contained a low proportion of animal matter, only gradually increasing with size, the nymphs of I. grammatica were carnivorous from very early instars. Both species switched to a temporarily strong utilization of algae in spring. This differed among sites, and appeared to reflect differences in insolation and thus the availability of algae. There was a significant negative relationship between the mean densities of Isoperla nymphs and the proportion of animal material found in the guts of I. grammatica (R 2 = 0.86). Considering the density of I. grammatica alone, the relationship was weaker (R 2 = 0.56). A positive correlation between predator and prey size was observed. With chironomid prey the size range increased with predator size. With simuliid prey, however, prey size increased with predator size in such a way that it suggests selection rather than just an expanding prey size range. Correlations were stronger and regression coefficients significantly higher for I. grammatica than for I. difformis. We suggest that I. grammatica, which ingests a much wider size range of prey might choose prey of optimal sizes more readily than the more synchronously developing I. difformis. Although the life cycles of the two species are staggered, overlap in size distribution indicates that competition for food could be important in spring. However, observed differences in diet should facilitate coexistence. Gut content differences might in turn be accomplished through microhabitat segregation.

Drumming Behavior of Four Western Nearctic Isoperla Species (Plecoptera: Perlodidae)

The drumming behaviors of four Isoperla species from the western Nearctic region are described for the first time. All have monophasic male calls and sequenced male-female exchanges. Isoperla miwok Bottorff & Szczytko males call with a mean of 5.7 beats and 25.3-ms beat intervals. Male-female drumming extends up to six-way exchanges. Isoperla acula Jewett males call with a mean of 4.1 beats and 356.8-ms beat intervals; male-female exchanges are two-way. Male calls appear to be produced by abdominal tapping and rubbing of the substrate. Drumming in I. acula differs greatly from that of the closely related I. mormona Banks, apparently helping these sympatric species maintain reproductive isolation. Isoperla adunca Jewett males call with a mean of 6.1 beats and 137.8-ms beat intervals. Isoperla bifurcata Szczytko & Stewart males call with a mean of 6.4 beats and 47.2-ms beat intervals; male-female exchanges are two-way. Some California Isoperla have similar male calls, but drumming is species-specific for the entire male-female behavior. Considerable variability in drumming behavior exists between and within the five species complexes of western Nearctic Isoperla. As a group, Isoperla displays many derived drumming traits.

Drumming as a Behavioral Line of Evidence for Delineating Species in the Genera Isoperla, Pteronarcys, and Taeniopteryx (Plecoptera)

The drumming behavior of nine Isoperla species, Pteronarcys pictetii Hagen, and two Taeniopteryx species are described for the first time. A derived form of drumming in Isoperla ouachita Stark and Stewart, consisting of male calls produced by abdominal rubbing, is reported for the first time in the Perlodidae. Use of drumming behavior as a line of evidence to delineate cryptic and sibling species groups within the genera Taeniopteryx, Pteronarcys, and Isoperla is examined. Male calling of Isoperla species varies from ancestral tapping to rubbing, and there is no overlap in important signal variables between sympatric species. There is no overlap of important drumming variables in the signals of known North American Taeniopteryx and Pteronarcys species, whose signals of both male and female are of a simple, ancestral type, with none of the derived states, such as diphasy or rubbing. Drumming in all known species of the three genera is species-specific, and largely corroborates morphologically based species separations.

Descriptions of Calliperla Banks, Rickera Jewett, and Two New Western Nearctic Isoperla Species (Plecoptera: Perlodidae)

Detailed descriptions of Calliperla Banks and Rickera Jewett, including males, females, ova, and larvae are provided. The adults of two new western Nearctic Isoperla species, I. baumanni and I. roguensis, are described. Rickera is removed from the Isoperlinae and placed as a valid genus within Perlodinae based on male and female genitalic characters, nymphal mouthparts, and ova characteristics. The Isoperlinae now includes Bulgaroperla, Calliperla, Cascadoperla, Clioperla, Isoperla, Kaszabia, and Mesoperlina.

Studies on egg development in the Fennoscandian Isoperla species (Plecoptera)

Three species of Isoperla occur in Fennoscandia. The most common is /. grammatica, although it has not been recorded above the subalpine vegetation belt. /. difformis has a similar distribution, but is less common. /. obscura occurs mainly at high latitudes and altitudes, although it is also abundant in large rivers. Eggs were reared at temperatures of 4, 8, 12, 16, 20 and 24° C. /. difformis did not hatch at 4° C. /. grammatica at 4 and 8° C while /. obscura did not hatch at 16° C and above. Egg mortality was high in /. difformis at 24° C. Incubation period decreased with increase in temperature and varied between 28 and 68 days in /. grammatica and between 15 and 83 days in /. difformis. For /. grammatica and /. difformis, the relationship between the egg incubation period and the water temperature was linear on logarithmic scales. For /. obscura, no such relationship was found and the mean incuba­ tion period at all temperatures was 305 ± 57 (S.D.) days. Explanations are presented to explain these differences in egg incubation characteristics.

The Effect of Temperature on the Oxygen Consumption of Three Species ofIsoperla(Plecoptera: Perlodidae)

ABSTRACT Oxygen consumption of Isoperla clio, I. namata and I. nana nymphs that simultaneously occupied the same habitat in Alabama was determined at nine different temperatures from 2.5–22.5 C on a Gilson Differential Respirometer. Q10 values indicated that I. clio was most sensitive to temperature change. Weight specific oxygen consumption-temperature relationship showed that the three Isoperla species had the same degree of tolerance to temperature, but the volume of oxygen consumed per unit body weight was inversely related to the species' mass. Generally the metabolic response to temperature change was dependent on body size and the stage of ontogenetic development.

Three new species of nearctic Isoperla (Plecoptera)

Nymphs and adults of three new species of Isoperla are described from reared ma- terial. /. sagittata is known only from southeastern Texas, I. coushatta has been collected in East Texas and Oklahoma, and I. jewetti occurs in the Basin and Range Mountains of West Texas. The male aedeagii, female subgenital plates, and nymphal mouthparts are diagnostic in all three species. Stewart et al. (1974) indicated that eastern Texas collections of Isoperla ap- peared close to I. riamata Frison and /. mohri Frison and that further study in- cluding comparisons with types was needed. They suggested that /. longiseta Banks, collected in 1939 by H. H. and J. A. Ross near El Paso, Texas, should be reexamined in light of Frison's reluc- tant identification, the brachypterous condition of the males and the similarities to I. mormona Banks that he mentioned. Additional collecting and rearing has been done in eastern Texas over the past two years, and all reared, adult, and nymphal material has been compared with paratypes and nymphs of similar species /. mohri , I. riamata , I. richardsoni Frison, I. burksi Frison, and I. davisi James, borrowed from the Illinois Natural History Survey. These studies emphasiz- ing comparisons of male aedeagii, color patterns, male paraprocts, female sub- genital plates, and nymphal mouthparts have revealed two previously undescribed species of Isoperla from East Texas. The eight vials of Isoperla , labeled /. longiseta by Frison in 1942 constituting the 1939 El Paso collection, were obtained from S. G. Jewett, Jr. and the Illinois Natural History Survey. The aedeagus of one male had been extruded and fixed, apparently at time of collection. Adult specimens and eggs dissected from fe- males were compared with those of typi- cal /. longiseta from the Green River in Utah and /. mormona from Wyoming. The one brachypterous male from La Veta Pass, Colorado, mentioned by Frison (1942) was also borrowed from the Illi- nois Natural History Survey and ex- amined. The aedeagus of /. longiseta males from Utah were extruded for study by clearing in a warm solution of 10% KOH and gently pressing the abdomen. The mouthparts of the four nymphal exuvia were studied and compared with nymphs from the Green River, Utah (the nymphs of I. longiseta are unde- scribed). These studies have confirmed that these Isoperla specimens from west Texas constitute an undescribed species.