Life history and secondary production of Electrogena ujhelyii (Ephemeroptera: Heptageniidae) in a small forest stream in West Carpathians

In this study we focused on life history parameters of Electrogena ujhelyii. We studied life cycle, nymphal growth pattern, biomass and secondary production in a small, calcareous stream in Malé Karpaty Mts (West Carpathians). The life cycle was univoltine with a large range in the size of nymphs during most samples dates. Mean annual density was 40 ind. m^?2 and the annual secondary production reached 183 mg DW m^?2 y^?1. There are no published data available on the secondary production values of this species, therefore these are the first published data.     

Heptageniidae (Insecta,Ephemeroptera) of Thailand

Nine genera and twenty-two species of heptageniid mayflies from Thailand are defined in this present work as well as one suggested further subgenus, Compsoneuria (Siamoneuria) kovaci (species “incertae sedis”) including some particular characters. Taxonomic remarks, diagnoses, line drawings of key characters, distribution, habitat and biological data, and a larval key to the genera and species are provided. The chorionic eggs of eight genera and eight species were observed and shown using a scanning electron microscope.     

Morphological and enzyme electrophoretic studies on the relationships of the European Epeorus species (Ephemeroptera, Heptageniidae)

Abstract. Forty-two enzyme-substrate systems were tested on starch gels in order to characterize the Ephemeroptera biochemically. Of these, twelve systems were useful and enabled the evaluation of sixteen loci. This biochemical method correlated well with the results of the morphological characterization of the four European Epeorus taxa, which are subdivided into two groups: E.sylvicola-E.torrentium and E.alpicola-E.yougoslavicus. Our biochemical comparison with the type species of Iron (I.longimanus) from North America clearly shows that all four European taxa belong to the genus Epeorus and that Iron is a distinct genus. Keys to larvae and imagines are provided.     

An electrophoretic and morphological study of three Ecdyonurus species (Ephemeroptera: Heptageniidae) occurring in the British Isles

Abstract The objective was to investigate the validity of three closely-related British species: Ecdyonurus dispar, E. venosus and E. torrentis . The species were characterized by eleven enzyme-substrates and fifteen different enzyme-loci, comparisons being made not only between species but also between five populations of E.dispar (three from Britain, one from France, one from Switzerland), two populations of E.venosus and two populations of E. torrentis (one from Britain, one from Switzerland for both species).
Four monomorph enzyme-loci (aldolase, mannose phosphate isomerase, arginine phosphokinase, glutamate-oxaloacetate transaminase-2) exhibited interspecific differences in their mobilities and therefore validated the conclusion that E. dispar, E. venosus and E. torrentis are distinct species. There were no monomorph enzyme-loci that were different between populations of the same species. There were, however, some intraspecific differences revealed by the presence of polymorphic enzyme-loci: seven in E.dispar (retinol dehydrogenase, hexokinase-1 and 2, glutamate-oxaloacetate transaminase-!, malate dehydrogenase-1, phospho-glucomutase, indophenol oxidase-2), three in E. venosus (glutamate-oxaloacetate transaminase-1, malate dehydrogenase-1, phospho-glucomutase) and three in E. torrentis (hexokinase-1, glutamate-oxaloacetate transaminase-1, malate dehydrogenase-1).
The morphological characters of larvae and adults were examined and some were used in new keys to larvae and adults.     

Water intake by the adult mayflyEpeorus ikanosis (Ephemeroptera: Heptageniidae) and its effect on their longevity

Water drinking habits during flight in adult mayflies ofEpeorus ikanonis Takahashi were observed and the effect of water intake on their longevity was examined. The study was carried out in a mountain stream in western Japan. Adult males collected a water droplet under the head capsule while alighting on the water surface and consumed it after moving to nearby riparian vegetation. The amount of water intake was experimentally estimated to be 9.7% of the bodyweight for males. Although females did not show the water drinking behavior in the field, they imbibed as much as 5.5% of the bodyweight of water in an experimental situation. Morphological observation of the mouthparts revealed that the water was drawn in through the pits at the base of the labrum. In the field caging experiment, males with a water supply had a substantially longer life span than those without. Increase in adult life span by drinking water was less marked in females. Multiple copulation was observed in both sexes during the experiment. The water drinking behavior of the males may closely relate to mating success through increased longevity. Variation in the longevity of adult mayflies was discussed with regard to the possibility of water intake. This paper forms part of a PhD thesis submitted to the Department of Zoology in Kyoto University (1990).     

Two phoretic black-flies (Diptera: Simuliidae) and their associated mayfly host (Ephemeroptera: Heptageniidae) in Cameroon

Simulium afronuri and S.lumbwanum are recorded living in association with nymphs of Afronurus in the forest zone of West Cameroon. Observations on infestation rates, attachment sites, larval size distribution and dispersion are recorded. Evidence of niche separation between the two simuliid species is discussed.     

The influence of diet on the growth of Stenonema vicarium (Walker) (Ephemeroptera: Heptageniidae)

Laboratory studies compared the growth rate of Stenonema vicarium (Walker) nymphs on diets of detritus and natural stream periphyton. In three consecutive runs of the experiment, growth rates were consistently higher on periphyton (mean growth rate = 2.1% wet wt. d⁻¹) than detritus (mean = 1.8% wet wt. d⁻¹). The starting date of each run also significantly influenced growth rates. In each treatment growth rates generally decreased over the course of the 3 runs, and ca. one-half of the nymphs in the last run did not molt or grow. It appeared that growth of S. vicarium may be partially controlled by seasonal factors.     

Effects of temperature on growth rate and behavior of Epeorus albertae (Ephemeroptera: Heptageniidae) nymphs

Anthropogenic disturbances affect temperature in river systems. Temperature potentially affects life histories of macroinvertebrates and alters behavior and biological functions. Temperature preferences and tolerance ranges for key taxa are therefore critical for understanding impacts of human-induced changes to water temperatures on river ecosystems. The objective of this study was to examine the effect of water temperature on growth rate and behavior of Epeorus albertae (McDunnough) nymphs. Nymphs were collected from the Umatilla River in eastern Oregon, and exposed to temperatures of 18, 22, and 28 °C. Nymphs held at 28 °C exhibited increased growth rates compared with individuals held at 18 and 22 °C. However, at 28 °C the accumulation of nymphal tissues was not consistent with that of nymphs held in lower temperatures; ratios of head capsule width to total body length were significantly lower in individuals at 28 °C compared with those held at the lower temperatures. This indicates that the nymphs held at the high temperature had longer total body length relative to the developmental stage, represented by head capsule width, when compared with insects in cooler temperatures. To examine the effect of water temperature on behavior, active drift of mayflies was examined in experimental chambers held at 12, 18, 22, and 28 °C. The number of drifting insects observed was significantly higher at 28 °C compared with 22, 18, and 12 °C. These results indicate that temperature is a factor influencing growth and behavior of E. albertae and is likely to lead to limitations in habitat use of this mayfly.     

Status of the enigmatic Oriental genus Rhithrogeniella Ulmer, 1939 (Ephemeroptera,Heptageniidae)

Based on historic collections and new material from Sumatra and Java, the species Rhithrogeniella ornata Ulmer, 1939, type species of the genus Rhithrogeniella, is reinvestigated. The nymph is described for the first time and is closely related to the continental Southeast Asian species Rhithrogeniella tonkinensis Soldán and Braasch, 1986. Rhithrogeniella belongs to the subfamily Ecdyonurinae, and is related to the genera Nixe Flowers, 1980 and/or Paracinygmula Bajkova, 1975 based on characters of the nymphal stage. Species described from Taiwan in the genus Nixe are transferred to the genus Rhithrogeniella: Rh. littoralis (Kang and Yang, 1994) comb. n., Rh. mitifica (Kang and Yang, 1994) comb. n. and Rh. obscura (Kang and Yang, 1994) comb. n.     

Rhithrogena trispina sp. n., a New Species from China (Ephemeroptera: Heptageniidae)

A new species, Rhithrogena trispina sp. n. from Tian-Mu-Shan Mountain of Southeast China, is described and figured in detail at the imaginal stage. From the position of gonopore on the penis lobe, it belongs to the znojkoi-group.     

Further observations on some blackflies (Diptera: Simuliidae) associated with mayflies (Ephemeroptera: Baetidae and Heptageniidae) in Cameroon

An account is given of the infestation rates, attachment sites, larval size distribution and dispersion of Simulium baetiphilum on nymphs of Baetidae. The mechanisms of choice shown by S. afronuri and S. lumbwanum infesting Afronurus spp. are discussed.     

Effect of temperature on larval growth of Ecdyonurus dispar (Ephemeroptera: Heptageniidae) from two English lakes

SUMMARY. Mature larvae of Ecdyonurus dispar were collected from Ennerdale Water and Windermere (English Lake District) and reared to adult males and females in the laboratory. The females were then fertilized artificially and their progeny were kept at constant temperatures (range 4.2–20.2°C). Larvae collected directly from the two lakes were also reared under the same conditions.
The maximum number of instars from egg to subimago was 25, the average body length increment (mm) per moult was proportionately constant at c . 15% and Dyar's rule was applicable. The interval between moults decreased with increasing temperature and the relationship between the two variables within the temperature range 4.2–19.8°C was described by a power law. Larval growth was exponential and variations in mean specific growth rate (range 0.23–5.23% length day⁻¹) were related to mean temperature which was the major factor affecting growth in the laboratory. A few experiments were also performed in the lake to test the adequacy of the estimated values for larval growth at different temperatures in the laboratory. There was agreement between the estimates and the actual growth rates in the lake. Therefore, the regression equations obtained from the laboratory experiments are probably applicable to larval growth in the field.
Values for daily production in the laboratory ranged from 0.53 to 9.33 mg dry wt day⁻¹ m⁻². The lowest value was obtained at 8.9°C and the highest at 20°C.
Information on different life cycles of E. dispar is briefly reviewed and it is concluded that E. dispar from the lakes can only achieve one generation per year.     

On the validity of Epeorella Ulmer, 1939 (Ephemeroptera,Heptageniidae) with general considerations on the Heptageniidae of the Sunda Islands

The type material of Epeorella borneonia Ulmer, 1939, the sole species of the genus Epeorella Ulmer, 1939 is reinvestigated and a lectotype (male imago) is designated. Based on several morphological structures, the synonymy with Epeorus Eaton, 1881 (Rhithrogeninae) is rejected. Epeorella stat. prop., known only at the winged stages, belongs to the subfamily Ecdyonurinae, and is a probable endemic of the island of Borneo. The newly erected genus Darthus Webb & McCafferty, 2007, also endemic to Borneo and only known by one species at the nymphal stage, is shown to be a junior subjective synonym of Epeorella. The new combination Epeorella vadora (Webb & McCafferty, 2007) is proposed for the species. The distribution of known heptageniid species from the Sunda Islands is discussed.     

A new species of Ulmeritoides from Brazil (Ephemeroptera: Leptophlebiidae)

The leptophlebiid mayfly genus Ulmeritoides is composed of nine species, three of which have been recorded in Brazil: U. patagianus, U. uruguayensis, and U. misionensis. In the present paper, a new species of this genus, Ulmeritoides oepa sp.nov., is described and illustrated based on fifteen larvae collected in Uraricoera River, state of Roraima, northern Brazil. The species was compared to U. misionensis, U. tifferae, and U. guanacaste, the other species of Ulmeritoides known from the larval stage. U. opea sp.nov. can be distinguished from these species by the following combination of characteristics: 1) medial denticle on anteromedian emargination of labrum much larger than others; 2) anterior tibiae slightly stained black toward the apex; 3) medial femora with few dorsal spines, similar to short thick needles; 4) hind femora with numerous dorsal spines, similar to short thick needles; 5) medial femora with no medial black markings, apical brown markings. The new species seems to be more closely related to U. misionensis, another species in which the anteromedian emargination of the labrum has a median denticle much larger than the others. The studied specimens were deposited in the Invertebrates Collection of the Amazonian Research National Institute, Manaus, state of Amazonas, Brazil, and in the Entomological Collection of the Department of Zoology, Federal University of Rio Janeiro, Rio de Janeiro, state of Rio de Janeiro, Brazil.     

Croatian mayflies (Insecta,Ephemeroptera): species diversity and distribution patterns

Knowledge of the mayfly biodiversity in the Balkan Peninsula is still far from complete. Compared to the neighbouring countries, the mayfly fauna in Croatia is very poorly known. Situated at the crossroads of central and Mediterranean Europe and the Balkan Peninsula, Croatia is divided into two ecoregions: Dinaric western Balkan and Pannonian lowland. Mayflies were sampled between 2003 and 2013 at 171 sites, and a total of 66 species was recorded. Combined with the literature data, the Croatian mayfly fauna reached a total of 79 taxa. Of these, 29 species were recorded for the first time in Croatia while 15 species were not previously recorded in Dinaric western Balkan ecoregion. Based on the mayfly assemblage, sampling sites were first structured by ecoregion and then by habitat type. In comparison with the surrounding countries, the Croatian mayfly fauna is the most similar to the Hungarian and Bosnian fauna. Some morphologically interesting taxa such as Baetis cf. nubecularis Eaton, 1898 and Rhithrogena from the diaphana group were recorded. Ephemera cf. parnassiana Demoulin, 1958, the species previously recorded only from Greece, was also recorded.     

Emergence patterns of three species of Caenis Stephens (Ephemeroptera: Caenidae)

Distribution of the watermould Achlya americana in Jabalpur, India, was investigated. The influence of temperature, pH, BOD, CO₂ and pollution is discussed.     

Three new species of Elassoneuria (Ephemeroptera: Oligoneuriidae) from tropical Africa

Three new species of Elassoneuria are described, E.disneyi from the Cameroons, and E.grandis and E.kidahi from Tanzania. The taxonomy of the nymphs is discussed, and E.congolana Navas is redescribed.     

New genera and species of Leptophlebiidae (Ephemeroptera) from New Zealand

Abstract

New genera Isothraulus, Arachnocolus, and Penniketellus are established for three species of leptophlebiid mayfly from New Zealand. Each genus is monotypic and endemic to New Zealand. Isothraulus and Arachnocolus are known only from the northern North Island, and Penniketellus is known only from the Arthur's Pass area of the central South Island. The male and female imago, nymph, and egg of Isothraulus abditus n.sp., the male imago, male subimago, and nymph of Arachnocolus phillipsi n.sp., and the male and female imago, female subimago, and egg of Penniketellus insolitus n.sp. are described. The relationships of each genus and the ecology of nymphs of each species are discussed.     

Description of the Imagines of Rhithrogena goeldlini Sartori and Sowa, 1988, and Keys for the Identification of Imagines of the European Species of the R. diaphana-Subgroup (Ephemeroptera: Heptageniidae)

The male and female imagines of Rhithrogena goeldlini Sartori and Sowa, 1988 are described and drawn on the basis of material collected in Portugal close to the type locality. Features distinguishing male imagines of the European species of the R. diaphana-subgroup are keyed.