Ephemeroptera Research Articles

NEW FOSSIL EPHEMEROPTERA AND COLEOPTERA FROM THE LADINIAN(MIDDLE TRIASSIC) OF CANTON TICINO (SWITZERLAND)

Two insects are described from the sediments of the uppermost Ladinian (Middle Triassic) of Meride (Canton Ticino, Switzerland). Tintorina triassica gen. n. sp. n., a representative of a new family, Tintoriniidae, of the Ephemeroptera, is described on the basis of two specimens, one being almost complete; a single elytron is ascribed to Notocupes sp. ind. (Cupedidae, Coleoptera). The ephemeroptera specimens possibly belong to a previously unrecognized Triassic suborder/order within the infraorder Ephemeroidea. Apart from the taxonomic interest of this find, it is pointed out that these are the first fossil insects found in the classic deposits of Monte San Giorgio-Besano, famous mostly for its vertebrates. The presence of Ephemeroptera confirms the existence of land with adjacent fresh-water basins where the preservation of many organisms in fine-grained matrix was possible.

In situ studies with Asian clams (Corbicula fluminea) detect acid mine drainage and nutrient inputs in low-order streams

In situ Asian clam (Corbicula fluminea [Müller]) studies may effectively mirror resident community responses to both acute toxicants and nutrient inputs in low-order streams. Clam survival and growth after 30 days in situ were compared with benthic macroinvertebrate community structural changes caused by acid mine drainage (AMD) and nutrient loading (measured as nitrate) in a small subwatershed of the North Fork Powell River, Virginia, U.S.A. Clam survival distinguished between two different levels of impact due to acidic, neutralized, and intermittent AMD inputs and was positively correlated with water column pH and negatively correlated with conductivity and metal con centrations. Survival was also positively correlated with relative abundance of the order Ephemeroptera, the most sensitive macroinvertebrate taxonomic group to AMD in this system. Clam growth was not related to AMD inputs but was positively correlated with nitrate concentrations and the relative abundance of the collector-filterer functional feeding group. These results suggest that transplanted clam studies accurately reflect benthic macroinvertebrate community responses to multiple stressors from point and nonpoint sources.

Mayflies

Mayflies

In situ studies with Asian clams (<i>Corbicula fluminea</i>) detect acid mine drainage and nutrient inputs in low-order streams

In situ Asian clam (Corbicula fluminea [Müller]) studies may effectively mirror resident community responses to both acute toxicants and nutrient inputs in low-order streams. Clam survival and growth after 30 days in situ were compared with benthic macroinvertebrate community structural changes caused by acid mine drainage (AMD) and nutrient loading (measured as nitrate) in a small subwatershed of the North Fork Powell River, Virginia, U.S.A. Clam survival distinguished between two different levels of impact due to acidic, neutralized, and intermittent AMD inputs and was positively correlated with water column pH and negatively correlated with conductivity and metal con centrations. Survival was also positively correlated with relative abundance of the order Ephemeroptera, the most sensitive macroinvertebrate taxonomic group to AMD in this system. Clam growth was not related to AMD inputs but was positively correlated with nitrate concentrations and the relative abundance of the collector-filterer functional feeding group. These results suggest that transplanted clam studies accurately reflect benthic macroinvertebrate community responses to multiple stressors from point and nonpoint sources.

Comparative Study of the Sediment-Toxicity Index, Benthic Community Metrics and Contaminant Concentrations

Abstract This paper demonstrates how a new tool for integrating the results of a battery of sediment toxicity tests can be effective in assessing the relative toxic potential of freshwater sediments to aquatic organisms. This tool, called the Sediment-Toxicity (SED-TOX) Index, was applied to laboratory toxicity data derived from two larger projects conducted on freshwater sediments. The SED-TOX Index generates a single value that represents all the results of the different STTs on a common, easily interpreted scale. The SED-TOX results were tentatively correlated with four benthic community metrics (species richness, number of taxa in the orders Ephemeroptera, Plecoptera and Trichoptera, the Shannon-Wiener diversity index, and the ICI-SL, which is a version of the invertebrate community index modified for the St. Lawrence River) and levels of sediment contamination. Although not significant (p = 0.07), SED-TOX scores were most closely related with ICI-SL values; high SED-TOX scores (≥2.0) were always associated with lower ICI-SL scores (<8), which suggests benthos degradation. Agreement was observed between chemistry and SED-TOX results in extreme situations. Indeed, 70% of the sites showing a high hazard potential (≥2.0) in the SED-TOX Index had mean sediment quality guideline (SQG) quotients >5, while 86% of those with a marginal SED-TOX score (0.1 to 0.9) had mean SQG quotients <1. The SED-TOX Index was useful for discriminating sediments based on their hazard potential to a variety of test species and for predicting most (but not all) of the extreme chemistry and benthic community results.

Chronic Toxicity of Ammonia to New Zealand Freshwater Invertebrates: A Mesocosm Study.

Freshwater macroinvertebrate communities were established within 12 artificial streams or "toroidal" mesocosms and exposed to three replicated concentrations of ammonia for 29 days at constant temperature (16 degrees C) and pH (median 8.4). The criterion units (CU = measured [ammonia]/US EPA 1985 chronic criterion value) of total ammonia in the LOW, MED, and HIGH treatments were 2.0, 4.8, and 13 CUs respectively, and 1.9, 5.8, and 12 CUs for the unionized ammonia. Macroinvertebrates were tolerant of the ammonia exposures with no significant (p > 0.1) effect on taxa richness; number of taxa in the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT); or the quantitative macroinvertebrate community index (QMCI), a biotic index proposed for assessing effects of organic enrichment in New Zealand streams. Significant differences (p < 0.05) occurred for the mean abundance and the numbers of EPT individuals (QEPT), with the HIGH treatment significantly lower (-41%) than the control for both abundance and QEPT. Of the major species, only the mayflies Deleatidium sp. (Ephemeroptera: Leptophlebiidae) and Coloburiscus humeralis (Ephemeroptera: Oligoneuriidae) showed significant reductions in abundance, with only the caddisflies Beraeoptera roria (Trichoptera: Conoesucidae) and Confluens sp. (Trichoptera: Conoesucidae) showing significant increases in abundance. The abundance of juvenile Deleatidium sp. had a negative concentration-response relationship that resulted in an 82% decrease in abundance in the HIGH treatment. Drift of invertebrates showed no response to ammonia treatments. The 29-day EC(50) values for Deleatidium sp. for total and unionized ammonia were 2.15 mg (N)/L (pH 8.4) and 0.145 mg (NH(3)-N)/L. No observed effect concentration (NOEC) values were 0.95 mg (N)/L and 0.066 mg (NH(3)-N)/L, and the threshold effect concentration (TEC) was 1.49 mg (N)/L and 0.102 mg (NH(3)-N)/L. Comparison of the Deleatidium sp. chronic ammonia sensitivity data with the US EPA 1985 chronic criterion value (CCC = 0.45 mg [N]/L, pH 8.4, 16 degrees C) showed the TEC value for total ammonia was 3.3x CCC, and 2.2x higher than the updated US EPA 1998 criteria. The findings suggest that use of the US EPA criteria would provide minimal protection for Deleatidium for chronic ammonia exposure, and that development of site-specific criteria, covering a wide range of environmental conditions, may be required to adequately protect this species.http://link.springer-ny.com/link/service/journals/00244/bibs/37n3p338.html

Structure and Production of a Benthic Insect Assemblage in a Neotropical Stream

The structure and production of a benthic insect assemblage were assessed over a 12-mo period in a neotropical stream draining the Caribbean slope of Costa Rica. Two stream habitats, riffles and pools, were sampled monthly. Benthic assemblage composition was similar to that reported for other areas in Central America and was dominated by the orders Ephemeroptera (Tricorythodes, Leptohyphes, Thraulodes, Baetis?), Coleoptera (Elmidae), and Diptera (mainly Chironomidae). Collector-gatherers were the dominant functional-feeding group and very few shredders were found. Annual habitat-weighted secondary production was highest for Tricorythodes (87.07 mg ash-free dry mass [AFDM] m^-2 y^-1) and Chironomidae (74.47 mg AFDM m^-2 y^-1). Total habitat-weighted secondary production was 363.65 mg AFDM m^-2 y^-1. Riffles supported the highest abundance, biomass, and secondary production of benthic insects. This study provides the 1st estimates of secondary production for a neotropical stream. Abundance, biomass, and secondary production in the study stream were low in comparison to results obtained in subtropical and temperate regions. However, annual production to biomass (P/B) ratios were high (range 5-103), indicating rapid population turnover. Monthly assessment of assemblage structure showed that benthic abundance increased with the number of days since the last large rainstorm (>50 mm/24 h). In addition, habitat-weighted abundance was negatively correlated with stream discharge. The abundance of macroconsumers (e.g., fishes and benthic shrimps) that potentially reduce food resources and prey upon insects might in part be responsible for the low abundance, production, and proportion of insect shredders in the study stream. Results suggest that other organisms (i.e., macroconsumers, microbes) are filling the functional roles that are normally assumed by benthic insects in temperate regions. Therefore, energy is potentially flowing through pathways other than insects from primary producers and detritus to upper trophic levels. In addition, precipitation and subsequent high discharge are major factors determining the structure of benthic communities in the study stream. Our results support the hypothesis that the structure and production of the benthic insect assemblage in this neotropical stream are the result of interactions between the physical environment (e.g., discharge and habitat type) and macroconsumers.

Flightlessness in mayflies and its relevance to hypotheses on the origin of insect flight

Until now, only fully winged mayflies have been known. It has been proposed recently that brachyptery could be a missing link in the development of insect flight, via sailing or skimming aquatic insects. To our knowledge, we report here the first documented case of brachyptery in mayflies. The flightless genus Cheirogenesia is endemic to Madagascar, and the adults skim the water surface. This loss of the flight function has induced important physiological changes, such as a shift from lipids to carbohydrates in the energy reserves used during their adult life. Comparison of wing area of living mayflies with fossil species indicates that brachyptery could have already occurred in early flying insects (in the Permian). We argue that flight loss in Cheirogenesia has been made possible by the lack of fish predation in its natural habitats.

Effects of heavy metals on benthic macroinvertebrate communities in New Zealand streams

AbstractWe performed chemical analyses of heavy metals in water and periphyton, toxicity tests with Daphnia magna and an indigenous mayfly (Deleatidium sp.), and field surveys of benthic macroinvertebrates to estimate the degree of metal pollution in three catchments in the Coromandel Peninsula of New Zealand. Good agreement was found between toxicity tests and measures of benthic community structure, particularly at stations with the highest metal levels. Responses of benthic communities at stations with low or moderate levels of metal contamination were variable and were probably confounded by factors other than heavy metals. Effects of heavy metals on benthic communities in New Zealand streams were similar to those reported for metal‐polluted streams in North America and Europe, suggesting that responses to metal contamination are predictable. Abundance and species richness of mayflies, number of taxa in the orders Ephemeroptera, Plecoptera, and Trichoptera, and total taxonomic richness were the best indicators of heavy metals in New Zealand streams. In contrast, the quantitative macroinvertebrate community index (QMCI), a biotic index proposed for assessing effects of organic enrichment in New Zealand streams, could not distinguish between reference and metal‐polluted streams. The poor performance of the QMCI was primarily due to incorrect tolerance scores for some taxa to heavy metals. Because of concerns regarding the subjective assignment of tolerance values to species, we recommend that tolerance values for dominant species in New Zealand streams should be verified experimentally in stream microcosms.

Effect of habitat type on benthic macro invertebrates in two lowland tropical streams, Costa Rica

Benthic macroinvenebrate community structure was studied with respect to stream habitat type in two lowland tropical streams. Three reaches along the Carbon river and two within tile Gandoca stream were chosen as study sites in Talamanca. Costa Rica. Macroinvenebrates were collected from four habitat types: leaf packs in rif­fles, cobble in rimes, areas of sand in pools, and areas of gravel in pools. Communities were dominated by in sec ts in the orders Ephemeroptera (Thraulodes, Baetis?. Diptera (Chironomidae. (Hydroptilidae, Glossomatidae, Hydroptilidae, Calamoceratidae), and Odonata inseci macroinvertcbrates (Progomphus. Hetarina). Non insect macroinvertebrates were dominated by shrimps (Macrobrachium) and snails (Gastrupoda). Functional feed­ing group composition was dominated by collector -gatherers. In most reaches, both habila1 types in riffles sup­ported higher macroinvertebrate abundance and biomass than did habitats in pools. Leaf packs in riffles represent an important habitat that is present year-round in these aseasonal tropical systems. Community composition and diversity were similar to that reported for other areas of Central America.

Ecologia de comunidades de insetos bentônicos (Ephemeroptera, Plecoptera e Trichoptera), em córregos do parque ecológico de Goiânia, Goiás, Brasil

Relationships among some abiotic factors (temperature, velocity, flow, conductivity, oxy-reduction potential and pH) and the seazonal density of benthic insects (immature forms) of the orders Ephemeroptera, Plecoptera and Trichoptera at the Parque Ecologico de Goiânia, Goias are studied. An area of 1m2 was sampled and abiotic factors were recorded in 4 sites from August/1994 to July/1995. The faunistic composition was 75% Ephemeroptera, 1% Plecoptera and 24% Trichoptera. The data suggest the water velocity and flow as the main factors that determined the aquatic insects abundance.

Conditions for the Return and Simulation of the Recovery of Burrowing Mayflies in Western Lake Erie

Conditions for the Return and Simulation of the Recovery of Burrowing Mayflies in Western Lake Erie

Heavy metal monitoring in contaminated river systems using Mayfly larvae

Insect larvae of the orders ephemeroptera (mayflies), plecoptera (stoneflies) and tricoptera (caddisflies) were investigated with respect to possible use as biomonitors of heavy metal pollution in rivers affected by current or previous mining activity. Samples from two rivers in central Norway were collected 3 times during the summer of 1985 and analyzed for Cu, Zn. and Cd. Of the three orders, mayflies was the only showing promise for further work. Repeated sampling of mayflies in one of the rivers in 1993 showed the same levels of Zn and Cd as before, whereas the copper level was reduced by a factor of 3. This may be explained by measures taken by the mining company upstream the sampling sites, reducing considerably the downstream transport of particles. Apparently Cu in this river is associated with particles to a much greater extent than Zn and Cd.

Recovery of a stream macroinvertebrate community from mine drainage disturbance

Recovery of aquatic macroinvertebrates from the effects of mine drainage was documented using a ‘weight-of-evidence’ approach which included measures of physical, chemical, and biological data. Taxa richness; number of taxa in the orders Ephemeroptera, Plecoptera, and Trichoptera; and shredder taxa richness all increased downstream of the point source after water treatment was initiated. Cluster analysis of aquatic macroinvertebrate community data along with abundance of a metals sensitive mayfly (Rhithrogena hageni) also suggested recovery from metals effects. Response to decreased metal inputs was rapid and biological measurements of impacted sites attained levels comparable to upstream reference sites in two years. Our results suggest that aquatic communities impacted by metals, in the absence of degraded habitat and with nearby colonist pools, will recover quickly if low instream concentrations of toxicants are achieved.

Differential behavioural responses of mayflies from streams with and without fish to trout odour

1. In streams, mayflies (Order Ephemeroptera) are at risk from fish feeding visually in the water column. The effect of fish odour on the behaviour of Baetis bicaudatus from a fishless stream and a trout stream was investigated in four large oval tanks supplied with water from the fishless stream.2. For each mayfly population, mayfly positioning on the substratum and movement in the water column (drift) were measured during the day and night, over 3 days. Brook trout (Salvelinus fontinalis) odour was added to two tanks to test the effect of a threat from fish.3. Throughout the experiment more mayflies from the trout stream were observed on the substratum surface and in the water column during the night than the day, but the magnitude of night drift was less in tanks with fish odour.4. Baetis from the fishless stream also displayed a nocturnal periodicity in drift and positioning, but their night‐time drift was not affected by the presence of fish odour. On the first day of the experiment, however, more mayflies were observed on the substratum surface and drifting in tanks without fish odour during the day.5. Sensitivity to fish odour may enable mayflies to alter their behaviour according to the risk of predation from fish.

Mayflies in May

Mayflies in May

An Update on the Occurrence of Three Species of Mayflies (Ephemeroptera) in Maine

Mayflies, members of the order Ephemeroptera, are a diverse group of aquatic insects. Unlike many kinds of insects that spend most of their lives on land, mayflies spend most of their lives in the water as immature forms called nymphs. Adult mayflies are short lived and reproduce soon after they complete their development to the final winged stage called an imago. Mated adult females deposit their eggs in the waters of streams and ponds, where they hatch. After hatching, nymphs live on or among the sediments and submerged stems of aquatic plants. Nymphs can feed and grow for as much as two years before they complete their development to the first winged stage called a subimago, but often this development is accomplished in one year or less. The subimago is a winged terrestrial form that usually flies away from the water to a place of safety where it soon sheds its skin and becomes the imago. For further details of mayfly biology the reader is directed to publications by Edmunds et al. (1976) and McCafferty (1981). In the late 1980's an extensive survey of Maine's mayfly fauna was conducted (Burian and Gibbs 1990). The results of that work showed Maine to have a diverse mayfly fauna with a majority of its 160 species broadly distributed from the mountains of the Moosehead Plateau to the coast. However, about 41 species (26% of the fauna) were recorded from less than three sites. Species such as these may indeed be rare, endemic, or indicative of special habitats. But, they may have been simply overlooked at other sites or were collected in a life stage that could not be determined to species. In general, mayflies with few records have ranges and habitat requirements that are largely unknown. For these species each new record improves our understanding of its range and habitat. This is especially important for the purpose of habitat management and conservation because critical decisions, usually involving rare species, cannot be made without basic range and habitat information. In this paper new locality records are presented for Siphlonurus securifer McDunnough, Metretopus borealis Eaton, and Hexagenia rigida Eaton, which have few known localities in Maine. Siphlonurus

Distributional And Classificatory Supplement To The Burrowing Mayflies

Distributional And Classificatory Supplement To The Burrowing Mayflies

Diet and Foraging Behavior of Vaux's Swifts in Northeastern Oregon

The diet ofVaux's Swifts (Chaetura vauxi) during the breeding season consisted primarily of insects in the orders Homoptera (hoppers, aphids, whiteflies), Diptera (flies), Ephemeroptera (mayflies), and Hymenoptera (ants, parasitic wasps). Diet was determined from 223 food boluses collected from adults feeding nestlings and represented 24,133 individual insects and spiders. Diet did not differ among five study areas or by time of day. A pair of swifts feeds an average of 5,344 arthropods to their nestlings each day, and an average of 154,976 arthropods during the nestling growth period. Radio-tagged swifts foraged up to 5.4 km from the nest. Of actual sightings of radiotagged birds, 64% were foraging over land, 27% were foraging over water, and 9% were traveling in a straight line.

Feeding Selectivity of the American Eel Anguilla rostrata (LeSueur) in the Upper Delaware River

-The population of American eels Anguilla rostrata (LeSueur) residing in the Upper Delaware River was sampled monthly from May through August 1986. Gastric examination of 325 eels captured by electrofishing revealed that 154 (47%) were empty and 171 (53%) contained food items. The specimens examined contained 2992 organisms of 59 taxa (four fish and 55 macroinvertebrate) and three non-organism categories. Macroinvertebrates, predominantly of the Class Insecta, were eaten by 169 eels (99% of feeding eels). The orders Ephemeroptera and Plecoptera occurred most often in eel stomachs (69%). The stonefly Acroneuria was the single most numerically dominant taxon observed in the diet, occurring in 67% of eel stomachs that contained food. Fishes were consumed by 12 eels (7%). The clustering near zero of electivity values for the overall study suggests that eels feed opportunistically on many macroinvertebrate taxa. The values also indicate that five food taxa were significantly (P < 0.05) selected as prey by American eels: Baetidae, Drunella, Perlidae, Hydropsyche and Polycentropodidae. The orders Ephemeroptera, Plecoptera and Trichoptera accounted for 92.7% of the organisms consumed, although they comprised 48. 1% of the available organisms. Ten food taxa were significantly (P < 0.05) avoided as prey by eels: Planaridae, Oligochaeta, Pelecypoda, Gastropoda, Gammaridae, Cheumatopsyche, Lepidostoma, Elmidae larvae, Dipteran pupae and Chironomidae. The insect orders Diptera and Coleoptera and the phylum Gastropoda accounted for 4.8% of the organisms consumed, although they comprised 32% of the available organisms.