Stonefly Species Research Articles

The numbers of nymphal instars of several Australian Plecoptera

Abstract The instar number of ten Australian stonefly (Plecoptera) species representing three families (Gripopterygidae, Eustheniidae, Austroperlidae) was found to range from 10–14. The conformance with Dyar's (1890) rule of the individual species was also determined and is discussed in terms of their life histories. Neboissoperla alpina has 11 instars and does not conform with Dyar's rule. Riekoperla rugosa, Acruroperla atra and Austropentura victoria have 10–11, 12 and 14 instars respectively, and conform well with Dyar's rule. Dinotoperla arenaria, Trinotoperla irrorata, Leptoperla kimminsi, Illiesoperla australis, Eunotoperla kershawi and Eusthenia venosa show uniform growth through the early instars, but do not conform with Dyar's rule in the later instars. D. arenaria has 11 instars, T. irrorata and L. kimminsi 12 and I. australis and E. kershawi 14. Instar number is different for male and female nymphs in E. venosa; the males have 13 and the females, 14. Instar number also varies with environmental temperature; the Aberfeldy River population of R. rugosa has 10 instars, while the population from a cooler habitat, Cement Creek, has 11. The application of the simple size frequency histogram and Janetschek (1967) methods in determining instar number in the Plecoptera are discussed. Interpretation of the simple histogram was found to be easier and as accurate as the Janetschek method. The application of Dyar's rule was useful in determining true instar peaks for both methods and in indicating the number and position of missing instar peaks for Stenoperla australis. S. australis appeared to have 12–14 instars.

Food habits and dietary overlap of perlid stoneflies (Plecoptera) in a tributary of Lake Ontario

Food habit studies were conducted on the nymphs of three species of sympatric perlid stoneflies from May to September 1979 in Orwell Brook, New York. A total of 1106 specimens were examined, which included 744 Phasganophora capitata, 251 Paragnetina immarginata, and 111 Acroneuria abnormis. Chironomids, trichopterans, and ephemeropterans were generally the principal, prey of all three species. Using Horn's measure of overlap, the monthly diets of P. immarginata and P. capitata were most similar [Formula: see text] and the diets of A. abnormis and P. immarginata[Formula: see text] least similar. Diel trends in food consumption during July indicated that the feeding intensity of both P. immarginata and P. capitata was the greatest from 2100 to 0500 hours. Examination of the guts of P. immarginata and P. capitata at 4-h intervals over a 24-h period showed that there was considerable variation in the diel diet composition of these species.

Live cycles, drift, and standing stocks of some stoneflies (Insecta: Plecoptera) from streams in Minnesota, U.S.A.

From analyses of monthly length frequency distributions of stonefly (Plecoptera) nymphs from stream riffles, two types of univoltine life cycles (Hynes 1961, classification) were observed: slow seasonal forIsoperla transmarina, Isoperla signata, Isogenoides olivaceus, andAllocapnia rickerii, and fast seasonal forProstoia similis. The Perlodidae stoneflies (Isoperla andIsogenoides) showed greatest propensities to drift near the end of their life cycles. Drift rates of the other two species of stoneflies were correlated to standing stock estimates.

Do Stonefly Predators Influence Benthic Distributions in Streams?

Experimental manipulations were conducted within the substrate of a Wisconsin stream and a Colorado stream to measure the effect of stonefly predators on the distribution of benthic invertebrates. Screen cages containing free predators, predators restricted from foraging, or no predators, allowed prey migration but no predator migration over 3—d periods. The presence of Acroneuria lycorias (Perlidae) in the Wisconsin stream significantly depressed the establishment of prey populations within cage microhabitats. Mechanisms for reduction were consumption of prey by the stonefly, and predator—avoidance by prey using contact and non—contact cues. The presence of Mergarcys signata (Perlodidae) reduced prey colonization in the Colorado stream by the same mechanisms, but restricted predators produced less consistent effects. This results could be due to colonization of cages by prey that could not detect predators without contact. Pternarcella badia (Pteronarcidae), a large stonefly detritivore that takes occasional prey, did not affect colonization of Colorado stream cages by prey. This differential response by prey to two moprphologically similar, but functionally different, stonefly species suggests that predator avoidance was not purely tactile. Chemotactile and non—contact chemical cues are possible mechanisms by which prey differentiated these stoneflies. The presence of A. lycorias and M. signata in experimental cages significantly increased the attrition of mayfly prey, compared to that from cages with no stonefly or a restricted stonefly in each stream. This result suggests that predation and avoidance by prey of contact with foraging predators were responsible for the higher disappearance of mayflies from cages. Free P. badia had a similar effect, probably due to tactile avoidance of this large detritivorous stonefly by some prey in the Colorado stream.

On the Biology of the Stonefly Species Leuctra digitata in a Northern Swedish Coastal Stream and its Adjacent Coastal Area (Plecoptera: Leuctridae)

On the Biology of the Stonefly Species Leuctra digitata in a Northern Swedish Coastal Stream and its Adjacent Coastal Area (Plecoptera: Leuctridae)

Interactions between Larval Size, Microdistribution and Substrate in the Stoneflies of an Iron-Rich Stream

Two species of stoneflies, Nemurella picteti Klapalek and Leuctra nigra Olivier, were abundant in a species-poor, iron-rich stream. N. picteti has a one year life cycle. At least some L. nigra larvae take two years to develop. Larvae of both species exhibited contagious dispersion patterns throughout the year. In general, larvae were over-represented in accumulations of allochthonous plant litter on which they feed. However, the younger larvae of L. nigra were relatively more common on stony substrate. Changes in distribution and abundance of the larvae through their development were related to their food supply and to intense predation pressure in the stream.

The endemism of Tasmanian stoneflies (Plecoptera)

Abstract Only 5, possibly 6, of the 47 species of Plecoptera known to occur on Tasmania and the 42 on the Australian mainland are common to the two areas. Three of these occur on King Island at the western end of Bass Strait, but only one on Flinders Island in the east where the strait is shallowest. Other species on the two islands are Tasmanian. The reasons for these distributions are discussed. It is suggested that the endemism can be explained by inhospitable conditions in the strait area during periods of lowered sea level in the Pleistocene, and that the western route is probably the one by which a few species did move. It seems to have been a difficult route, and one stonefly species became isolated on King Island for long enough to evolve a subspecies.

Stonefly (Plecoptera) Food Habits and Prey Preference in the Dolores River, Colorado

Gut contents of 1013 stonefly nymphs, comprising nine species, from the Dolores River, Colorado, were analyzed from December 1974-October 1975 and compared with food availability. Pteryonarcyids ingested large quantities of detritus and some moss, moss being a substantial food item in later instar Pternarcella badia nymphs. Perlodids fed primarily on chironomids and simuliids, although Isoperla fulva also ingested mayflies in June. Claassenia sabulosa remained carnivorous throughout development: young nymphs ingested chironomids and small mayflies and larger nymphs ingested caddisflies and mayflies. Horn's Coefficient of Dietary Overlap indicated significant overlap between all perlodids and chloroperlids. It also showed significant overlap between small and large C. sabulosa nymphs, yet selection of different prey sizes indicated resource partitioning. A comparison of food habits with the Gunnison River stoneflies indicated differences between the diets of large and small Claassenia sabulosa, with chironomids comprising large percentages of the diet for both size classes in the Gunnison River and smaller nymphs in the Dolores. Mayflies were important prey for larger individuals in the Dolores River. These differences could be attributed to different prey populations in each river and/or to availability of prey in the particular size that each predator preferred. In both rivers, Chironomidae and Simuliidae larvae were the major prey in the guts of Cultus aestivalis and Isoperla fulva. This prey specificity may have been due to decreased availability of smaller individuals in the other major prey groups or a difficulty in capture of larger prey organisms. INTRODUCTION Fuller and Stewart (1977) discussed stonefly food habits and showed that seasonal-developmental shifts occurred in nymphal diets and food preferences among 10 species in the Gunnison River, Colorado. They also addressed dietary overlap, prey size electivity, resource partitioning and diel periodicity in feeding. Earlier studies by Muttkowski and Smith (1929), Hynes (1941), Brinck (1949), Jones (1950), Mackereth (1957) and Richardson and Gaufin (1971) dealt only with gut analyses and descriptive aspects of feeding. More recent studies have reported seasonal fluctuations in diets (Tarter and Krumholz, 1971; Sheldon, 1972; Vaught and Stewart, 1974; Cather and Gaufin, 1975), yet only one (Siegfried and Knight, 1976) contains information on prey availability. When feeding habits of specific taxa are compared between river systems, prey availability data are essential before any conclusions can be drawn about a predator's preference or selection for particular prey taxa. This article describes a study made of food habits and prey selection by nine stonefly species in the Dolores River, Colo. The research was done concurrently with that reported by Fuller and Stewart (1977) on the Gunnison River, Colo., and comparisons will be made for the eight species encountered in both rivers December 1974 October 1975. STUDY RIVER AND METHODS Headwaters of the Dolores River originate on the S slope of the San Miguel mountains in southwestern Colorado. The West and East Forks converge about 13 miles above Dolores, and the river flows southwestward to Dolores, thence north' Study supported in part by U.S. Environmental Protection Agency Traineeship #T900115 and North Texas State University Faculty Research Fund Grants # 34866 and 34905. 2 Present address: Department of Zoology, University of Toronto, Toronto, M5S, lAl, Ontario, Canada.

Drumming Behavior of Eleven Nearctic Stonefly (Plecoptera) Species1

Drumming was recorded for 11 of 13 Nearctic stonefly species, representing 4 families. Both ♂ and ♀ signals were obtained from 5 species, and were either 2-way or 3-way communications. Signals were species-specific; those of males and females varied from 3–39 and 1–14 beats/signal, respectively. Duration of ♂ signals varied from 105–8016 ms; those of females except Perlinella drymo (1 beat), varied from 402–1318 ms. Signals among related taxa showed greatest similarities. Duration of ♂ signals of Perlinella drymo became progressively shorter at each of 4 temperatures from 7–29°C. Females of Perlinella drymo would only repeatedly answer ♂ signals recorded at near their own temperature, and would not repeatedly answer recorded ♂ signals of 8 other species.

Utaperla gaspesiana sp. nov., le premier Plécoptère Paraperliné de l'Est canadien

The adult male of Utaperla gaspesiana, a new species of stonefly from the Gaspé Peninsula (Quebec), is described and illustrated. This is the first record of a member of the Paraperlinae (Chloroperlidae) from Eastern Canada. The relations of this new species with the other two known species of the genus, the western nearctic U. sopladora and the eastern palaearctic U. orientalis are briefly discussed.

Some stoneflies from Bangladesh, India and Southeast Asia

Abstract Collection data are given for fourteen species of stoneflies from Bangladesh, India and Southeast Asia. Described as new are Rhopalopsole bakeri from Malaysia, Rhopalopsole bicornuta from Malaysia, Phanoperla sertisplna from India and Neoperla hamata from India.

Autohemorrhage in Two Stoneflies (Plecoptera) and its Effectiveness as a Defense Mechanism

Adults of the stoneflies Pteronarcys proteus Newman and Peltoperla maria Needham and Smith autohemorrhage at the intersegmental membranes of the coxial and tibio-femoral joints of the legs when subjected to traumatizing stimuli. Autohemorrhage in both species of stoneflies is an effective defense mechanism against certain ants. There is some evidence to suggest that a “popping” sound accompanying autohemorrhage in P. proteus may delay attack of certain vertebrate predators.

Arthropoda of the subantarctic islands of New Zealand

Six gripopterygid stonefly species are found on New Zealand's subantarctic islands. They belong to the genera Apteryoperla and Aucklandobius, which are endemic to New Zealand and those islands. The only winged species, Aucklandobius complementarius Enderlein, is found on the Auckland Islands with A. gressitti n.sp., Apteryoperla turbotti lilies, and A. kuscheli n.sp. Campbell Island is inhabited by Apteryoperla campbelli lilies and A. longicauda lilies; there is also a doubtful record of Aucklandobius complementarius. All Apteryoperla species except longicauda have terrestrial larvae.

Hyporheic Communities of Two Montana Rivers

Collections of stream organisms from a domestic water supply system adjacent to the Tobacco River revealed that a detritus-based community exists in subterranean waters circulating through floodplain gravels at least 4.2 meters below and 50 meters laterally from the river channel. Several stone fly species spend their entire nymphal life cycles in underground habitats of the Flathead and Tobacco rivers.

Effect of Low Oxygen Concentration on Survival and Emergence of Aquatic Insects

Safe concentrations of dissolved oxygen for survival and adult emergence of larvae of nine species of aquatic insects, including mayflies, stoneflies, caddisflies, and midges, ranged from 0.6 mg/liter for the midge Tanytarsus dissimilis to slightly less than saturation for the emergence of Ephemera simulans (18.5 C). All species tested were less tolerant of low oxygen concentrations for 30 days than for 96 hours (90% of E. simulans survived 4 mg/liter for 96 hours, but no adults emerged successfully). Long-term studies are essential for the accurate assessment of oxygen stress in aquatic insects.

Plécoptères nouveaux du Québec (Insectes)

Isoperla gibbsae n. sp. and I. francesca n. sp. are described from Southern Quebec. Nemocapnia Carolina, Perlinella drymo, and Isoperla signata are reported for the first time from Quebec and notes are given on the distributions of Isoperla similis and Hastaperla orpha in the province. The number of stonefly species known from Quebec is now 102.

The life histories of some Plecoptera and Ephemeroptera in a southern Ontario stream

The life cycles of 4 species of stonefly and 11 of mayfly are described, based upon the flight season of the adults and measurements of nymphs collected at all seasons from the Speed River. It is shown that they fit into all but one of the categories of life cycle that have been described for stream insects in Europe, and that where more than one species of the same genus coexist there is usually a marked difference in the timing of their life histories.

Cycles vitaux de quelques Plécoptères des Laurentides (insectes)

Twenty-four species of stoneflies (Plecoptera) were collected in the streams of the Station de Biologie de l'Université de Montréal, at Saint-Hippolyte in Terrebonne county (46°00′ N, 74°00′ W). Sampling of larvae and adults at regular intervals showed the distribution of the species in the stream and the seasonal succession of the adults. The Capniidae and the Taeniopterygidae appear in early spring; the remaining species emerge in May and June. The emergence of a single species Leuctra tenuis extends into July and August. No true autumnal species was found. Larval growth of the more common species is described; these are Taeniopteryx burksi, Paracapnia opis, Isoperla frisoni, Isoperla lata, Hastaperla brevis, and Paragnetina media. Biological notes concerning the other species are included.

A new species of stonefly of the family Gripopterygidae (Plecoptera) from Uruguay

A new species of stonefly of the family Gripopterygidae (Plecoptera) from Uruguay

North American Species of Taeniopteryx (Plecoptera, Insecta)

Keys, synonymy, descriptions, and distribution records are given for the eight American stonefly species of the genus Taeniopteryx Pictet, including the new species burksi, lonicera, metequi, and ugola.