A 9‐year study of the life cycle of Ephemera danica Müll. (Ephemeridae: Ephemeroptera) in the River Lambourn, England

Abstract

Abstract. 1. The life cycle of the mayfly, Ephemera danica, was studied on two contrasted sites on the River Lambourn between 1971 and 1979.2. Quantitative samples of nymphs were taken on the five major biotopes of the river bed, gravel, silt, Ranunculus, Berula and Callitriche. Exposed areas of gravel and silt held significantly lower densities of nymphs than the three macro‐phytes with their underlying substrata. The sandy substratum underlying beds of Berula frequently held significantly higher densities than the other macrophytes.3. Monthly samples from March 1971 to April 1972 followed by samples in June and December from 1972 to 1979 indicated that the nymphal phase normally took 2 years in the River Lambourn.4. All odd‐numbered years from 1971 to 1979 produced weak year‐classes. In contrast, all even‐numbered years between 1970 and 1978, with the exception of 1972, produced relatively strong year‐classes.5. Meteorological data for the period of flight activity in E.danica indicated that conditions were colder and damper in 1972 than in the other even‐numbered years of the study, when recruitment was more successful.

Modelling lake macroinvertebrate species in the shallow sublittoral: relative roles of habitat, lake morphology, aquatic chemistry and sediment composition

“…The riparian cover of woody shrubs & seedlings was a significant factor influencing the mayfly Ephemera danica. Riparian vegetation cover might be important in providing shelter from wind for adults, although Wright et al (1981) did not find higher nymph density on a river site with trees compared to one with open grassland. However, further examination of the distribution of mayflies may reveal closer associations with riparian habitat quality/ecotone integrity as this is likely to be a key requirement for adult life stages.…”

The influence of abiotic factors and density-dependent mechanisms on between-year variations in a stream invertebrate community

“…In agreement with results from other long-term studies (Wright, 1978;Wright, Hiley & Berrie, 1981;Colbo, 1985), variations between years are common in stream invertebrate communities. The stability in the population densities appears rather weak.…”

“…Wright et al (1981) in a 9-year study of the mayfly Ephemera danica Mtiller in an English chalk river observed important annual variations and suggested that good climatic conditions during the flight period were critical for good recruitment. Other papers report annual variations in depteran populations (Chironomidae, Wright, 1978 ;Drake, 198 1;and Simuliidae, Colbo, 1985).…”

Life history of a lowland burrowing mayfly, Ephemera orientalis (Ephemeroptera: Ephemeridae), in a Korean stream

“…For example, cooler geographic regions at higher latitudes cause delayed development and reduced numbers of generations per year in ephemerid mayflies (Clifford, 1982;Corkum & Hanes, 1992;Newbold et al, 1994) and various other aquatic insects (Ward & Stanford, 1982;Sweeney, 1984;Brittain, 1990). Detailed studies on a riverine ephemerid mayfly, Ephemera danica, showed that it has a 2 or 3-year life cycle in Europe depending on its location in France (Thibault, 1971), Sweden (Svensson, 1977), Spain (AguayoCorraliza et al, 1991), and Britain (Wright et al, 1981;Tokeshi, 1985). A lacustrine burrowing mayfly, Hexagenia limbata, also showed a linear relationship between voltinism and latitudinal location in North America (Heise et al, 1987).…”