Genera Of Ephemeroptera Research Articles

Gêneros de Ephemeroptera como biodindicadores de impactos agrícolas em córregos da Mata Atlântica

ABSTRACT Insects of the Ephemeroptera order have been used as bioindicators of water quality as they respond to countless anthropic impacts. In this study, we assessed the use of Ephemeroptera as bioindicators of streams impacted by agricultural activities. We collected Ephemeroptera nymphs in six streams with different uses and soil cover in their drainage areas located in the northern region of the Brazilian state of Rio Grande do Sul. Based on soil use and cover analysis, we categorized the streams as ‘natural’ (drainage area with >42% native arboreal vegetation) and ‘agricultural’ (drainage area with >72% agricultural use). We collected a total of 2,767 organisms, distributed into four families and eleven genera. We observed greater abundance (68%) and taxonomic richness (11 genera) of Ephemeroptera in the agricultural streams. The natural streams comprise 32% of the fauna collected, with eight genera. That pattern was especially determined by the Baetidae and Leptohyphidae families. The genera Caenis, Cloeodes, and Tricorythopsis were abundant in the agricultural streams. In this study, we observed that genera of Ephemeroptera are tolerant to environmental changes, particularly those caused by agricultural activities. Therefore, the use of the order in studies to assess water quality must be carried out with caution.

Ecological Effects of Road De-Icing Salt on Adirondack Forests and Headwater Streams

We collected water samples from upstream and downstream sites over 3 years on 18 study streams in the Adirondacks, NY, and conducted analysis via ANOVA for the presence of road-salt runoff, as measured by chloride ion content. Streams crossed by state roads received more road-salt runoff than streams crossed by county roads, as shown by higher mean chloride loads across different sampling years (P ≤ 0.01). The chloride load in streams was not reliably higher downstream from a road as opposed to upstream from a road for either state or county roads but varied in different sampling years (P 0.05). We collected a total of 1259 nymphs of Ephemeroptera, Plecoptera, and Trichoptera during water sampling. High levels of road-salt runoff were not associated with lower levels of Plecoptera or Trichoptera. Neither numbers of individuals nor numbers of genera of Ephemeroptera, Plecoptera, or Trichoptera collected per month showed any pattern when regressed on stream-chloride level. However, we detected no Ephemeroptera above a relatively high level of road-salt runoff (154 mg/L chloride ion). We employed the point-centered quarter method to assess forest composition on 10 transects above and below state roads. We conducted further analysis on trees in the lowest quartile of circumference in each transect as a representation of tree-species recruitment. Mean chloride-ion content of study streams, indicating adjacent forest exposure to road-salt runoff, was associated with greater recruitment of Abies balsamea (Balsam Fir), and lower Shannon–Weiner diversity. At the highest chloride levels, there was almost no recruitment of any species but Balsam Fir. Soil-cation analysis and linear regression, however, did not indicate concomitant depletion of plant nutrients, and therefore, we did not confirm the cause of the apparent relationship between higher road-salt runoff and higher Balsam Fir recruitment.

Temperature and daily emergence of seven genera of Ephemeroptera (Insecta) in a cloud forest stream of tropical Andes

Daily emergence of mayflies in Neotropical rivers and their causes have been poorly studied. In temperate zones, this process is better known and attributed to several factors. In this work, we studied the daily emergence of subimagines of several Ephemeroptera genera in La Picón River of a Venezuelan Andean cloud forest and its relation with changes of environmental temperature. Four emergence traps were placed along a reach of 50 m of the stream, each one was examined each two hours in a 24 hr cycle to capture the newly emerged subimagos. This procedure was repeated for eight dates between November-2007 and February-2008 for a total of 32 observations in each sampling hour. The subimagos were reared to adults and identified to genus. The relative density of emergence per trap was calculated for each genus and sampling hour. Water and air temperature were measured each hour during the daily cycle of observation, and the averages of temperature and hour-degrees of air and water were calculated for each hour from the eight dates studied. Seven genera were identified: Leptohyphes Eaton, 1882 and Haplohyphes Allen 1966 (Leptophlebiidae); Prebaetodes Lugo-Ortiz and McCafferty, 1996, Andesiops Lugo-Ortiz and McCafferty, 1999, Baetodes Needham and Murphy, 1924 and Americabaetis Kluge, 1992 (Baetidae); and Thraulodes Ulmer, 1920 (Leptophlebiidae); being the more abundant Leptohyphes (38.4 %) and Thraulodes (20.5 %). The emergence occurred between 11:00 am and 23:00 pm showing the following: a) an emergence initiated during daylight hours by organisms of Leptohyphes, Prebaetodes and Haplohyphes; b) a nocturnal emergence, in Thraulodes, Andesiops, Baetodes and Americabaetis; and c) two peaks: one diurnal produced by Leptohyphes and other nocturnal with predominance of Thraulodes. These results are the first records on the diurnal daily emergence in Andesiops, Prebaetodes, Americabaetis, Haplohyphes, and Leptohyphes, as well as the nocturnal emergence in Thraulodes. It was evidenced that Leptohyphes, with small nymphs (average head width = 1.05 mm) needed to accumulate less hour-degrees to initiate the emergence than those required by Thraulodes whose nymphs are larger (average head width = 2.01 mm). This disparity in the emergence energy requirements must be consequence of differences between the sizes of mature nymphs of both genera; facts which rely on the constancy of sizes shown by these taxa along an altitudinal-thermal gradient and the little daily and seasonal variability of water temperature in La Picón River. In the daily lapse when the emergence occurred, the air and water average temperatures were higher than those registered in the no-emergence lapse; therefore; it is suggested that during the daily lapse, when this process occurs, the environment is thermally favorable for the emergence of subimagos and their survival out of water.

Ephemeroptera (Insecta) de Caldas - Colombia, claves taxonómicas para los géneros y notas sobre su distribución

With the aim of contribute to the knowledge of taxonomy and distribution of the genera of the order Ephemeroptera in Caldas, samples were taken between May of 2008 and May of 2012 in 12 municipalities of the department of Caldas - Colombia, covering an altitudinal range from 159 to 3433 m and a total of 55 water sources. Six families and 26 genera of Ephemeroptera were found, of which Cabecar is a new record for Colombia, also recording for the first time the nymphs of Tikuna and Ulmeritoides for the country. Americabaetis, Apobaetis, Callibaetis, Cloeodes, Guajirolus, Paracloeodes, Cabecar, Traveryphes, Tricorythodes, Terpides, Tikuna, Ulmeritoides, Caenis and Campsurus are new records for Caldas. Differences in the composition of the fauna in the diverse altitudinal zones were found, being the areas below 1000 m with highest genera richness.

A new species of Campsurus (Ephemeroptera: Polymitarcyidae: Campsurinae) from Argentina and Uruguay and redescription of C. evanidus and C. jorgenseni with new synonymies

The subfamily Campsurinae (Ephemeroptera: Polymitarcyidae) includes one of the most specious genera of Ephemeroptera, Campsurus (with 40 known species), with a Pan-American distribution and its greatest diversity in South America. The following new synonymies are proposed: C. evanidus Needham & Murphy, 1924 (=C. juradinus Navás, 1930) and C. jorgenseni Esben-Petersen, 1912 (=C. scutellaris Needham & Murphy, 1924). Redescriptions, drawings and photographs are provided for both species. C. vulturorum sp. nov. from Argentina and Uruguay is described and illustrated for all life stages. It is characterized, in the adult stage, by: very large size (male fore wings 15.9–20.5 mm, female fore wings 21.0–28.0 mm), posterior margin of male abdominal sternum IX convex and rounded, pedestals subrectangular with a short projection on outer-posterior margin; penes widely separated distally, each arm formed by two lobes; and in mature nymphs by: mandibular tusks robust with a large submedian tubercle and six subapical rounded and small tubercles, maxilla with a short flat and triangular membranous gill on cardo.