Etude expérimentale de Tincubation des oeufs de <i>Baetis rhodani</i> Pictet

Bénech, Vincent; Vignes, Jean Claude

doi:10.1111/j.1365-2427.1972.tb00053.x

Cited by 22 publications

(13 citation statements)

References 6 publications

(2 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our large-scale estimates were based on 1-km stream lengths, but extrapolating to longer lengths may be reasonable provided there are no changes in channel morphology, hydrology or sediment supply. Most estimates of hatching success in Baetis suggest that [90% of eggs hatch successfully (Benech 1972a;Elliott 1972;Peckarsky et al 2000), and this suggests that differences in scaled estimates of egg mass density across our four streams (0.86-2.2 m -2 ) translates into a &2.5-fold difference in neonate density at the start of larval life. Of course, subsequent mortality may override such differences and, indeed, density-dependent larval mortality has been observed in some other stream insects (Otto and Svensson 1976;Hildrew et al 2004).…”

Section: Discussionmentioning

confidence: 94%

“…Our streams were at latitudes between these extremes (55°48 0 N) and we suspect bivoltine populations with long emergence periods and overlapping generations (see ''Results''), as observed in a river at similar latitude (55°20 0 N) and approximately 70 km away (Wise 1980). Like other species in the genus Baetis, egg-laying females of B. rhodani land on emergent rocks, usually in fast-flowing water, walk underwater and oviposit on the underside of the emergent rocks (Eaton 1888;Benech 1972a;Elliott 1972). If rocks are imbricated, females may lay egg masses on adjacent rocks (often fully submerged), but this accounts for a tiny fraction of all egg masses laid.…”

Section: Study Organismmentioning

confidence: 92%

See 1 more Smart Citation

Environmental constraints on oviposition limit egg supply of a stream insect at multiple scales

2010

View full text Add to dashboard Cite

Species with complex life cycles pose challenges for understanding what processes regulate population densities, especially if some life stages disperse. Most studies of such animals that are thought to be recruitment limited focus on the idea that juvenile mortality limits the density of recruits (and hence population density), fewer consider the possibility that egg supply may be important. For species that oviposit on specific substrata, environmental constraints on oviposition sites may limit egg supply. Female mayflies in the genus Baetis lay egg masses on the underside of stream rocks that emerge above the water's surface. We tested the hypothesis that egg mass densities are constrained by emergent rock densities within and between streams, by counting egg masses on emergent rocks. All emergent rocks were counted along 1-km lengths of four streams, revealing significant variation in emergent rock density within streams and a more than three-fold difference between streams. In each stream, egg mass density increased with the density of emergent rocks in 30-m stretches. We used regression equations describing these small-scale relationships, coupled with the large-scale spatial variation of emergent rocks, to estimate egg mass densities for each 1-km stream length, a scale relevant to population processes. Scaled estimates were positively associated with emergent rock density and provided better estimates than methods that ignored environmental variation. Egg mass crowding was inversely related to emergent rock density at the stream scale, a pattern consistent with the idea that oviposition substrata were in short supply in streams with few emergent rocks, but crowding did not compensate entirely for differences in emergent rock densities. The notion that egg supply, not larval mortality, may limit population density is an unusual perspective for stream insects. Environmental constraints on egg supply may be widespread among other species with specialised oviposition behaviours.

show abstract

Section: Discussionmentioning

confidence: 94%

Section: Study Organismmentioning

confidence: 92%

Environmental constraints on oviposition limit egg supply of a stream insect at multiple scales

2010

View full text Add to dashboard Cite

show abstract

“…The composite regression line for the two orders is drawn. Data from the following sources : Benech 1972b, Brittain 1977, Brittain and Lillehammer -1987, Brittain and Mutch 1984, Broch 1986, Elliott 1972, Friesen et al 1979, Haland 1981, Humpesch 1980, Humpesch and Elliott 1980, Lillehammer 1985, 1987a, b, Mutch and Pritchard 1982, Newell and Minshall 1978, Rekstad 1979 Table 2. Regression analysis for the relationship between the two constants 'a' and 'b' in the regression equation for the relationship between water temperature and the length of the egg incubation period in species of Ephemeroptera and Plecoptera.…”

Section: Oenone 5 10mentioning

confidence: 99%

Life History Strategies in Ephemeroptera and Plecoptera

Brittain

1990

Mayflies and Stoneflies: Life Histories and Biology

103

View full text Add to dashboard Cite

ABSTRACfThe major part of the life of Ephemeroptera (mayflies) and Plecoptera (stoneflies) is spent in the aquatic environment, while their short terrestrial life is primarily concerned with reproduction. Such a complex cycle passing through two different phases, each having its own selection pressures, places evolutionary constraints on life cycle strategies.Stoneflies are mostly cool water species. They have also evolved brachyptery and mating occurs on the ground or other surface beside the aquatic habitat. In contrast, mayflies are common in tropical waters, show no brachyptery and invariably mate in flight, often at considerable distances from the aquatic habitat.Water temperature is a major factor governing egg development and although showing the same general relationship between water temperature and the length of egg development mayflies have a greater thermal demand and are more temperature dependent than stoneflies. Nymphal growth rates are also compared and related to their life history strategies.Univoltine life cycles are most common in both orders, but in mayflies multivoltine cycles are also common, especially in tropical and temperate regions, whereas semivoltine life cycles are generally restricted to certain taxa. In stoneflies, however, semivoltine cycles are common, while multivoltine cycles are rare.These differences between the two orders explain the greater intrusion of stoneflies into arctic and alpine areas and that of mayflies into the tropics. INTRODUCfIONThe Ephemeroptera and Plecoptera are two small orders of aquatic insects each numbering about 2,000 species. They are widely distributed throughout the world and occur in all continents apart from Antarctica, although poorly represented on oceanicislands. Their conservative dispersal makes them useful objects for biogeographic analysis (e.g. lilies 1965, Rauser 1971, Edmunds 1972.In contrast to representatives of orders such as the Coleoptera and Hemiptera, they are primary I.C. Campbell (ed.) Mayjlies and Stonejlies, 1-12. © 1990 Kluwer Academic Publishers. invaders of the aquatic environment and both orders possessed aquatic nymphs at least 250 million years ago. They have subsequently become highly adapted to the aquatic mode of life, and their immature stages are, with only a few exceptions, exclusively aquatic and restricted to freshwaters. However, both orders have complex life cycles (Wilbur 1980) involving both aquatic and terrestrial phases. Such life cycles create evolutionary dichotomy with selection pressure operating in two, more or less independent, environments. Such dichotomy will theoretically lead to the reduction of either the terrestrial or 2 aquatic phase. Coordinated evolution between the two phases may occur, but this will retard evolutionary change in general (Istock 1967).A reduction in one of the phases has clearly happened in both orders, notably in the Ephemeroptera, but also to a considerable degree in the Plecoptera. The adult stage in both orders is of limited duration and has almost the sole funct...

show abstract

“…Lancaster, Downes & Arnold (2010, 2011) found positive relationships between egg mass density and both the density of emergent stones and the density of neonate and mid‐stage larvae of B. rhodani in four streams. In experimental studies in both the laboratory and the field, eggs hatched over a wide range of water temperatures (3.0–25.0 °C), and the time taken for the eggs to hatch decreased with increasing temperature, for example 66 days for 50% hatch at 5 °C but only 26 days at 10 °C (Bohle, 1969; Benech, 1972a; Elliott, 1972). However, once the eggs started to hatch, the period over which hatching occurred was short, for example less the 10 days at water temperatures above 5 °C (Elliott, 1972).…”

Section: Introductionmentioning

confidence: 99%

Contrasting dynamics from egg to adult in the life cycle of summer and overwintering generations ofBaetis rhodaniin a small stream

Elliott

2013

Freshwater Biology

View full text Add to dashboard Cite

Summary 1. The chief objectives were as follows: (i) to describe and compare quantitatively the life cycles of the summer and overwintering generations of Baetis rhodani, including laboratory experiments to determine the number of eggs laid per female and the number of larval instars; (ii) to test Dyar’s hypothesis; and (iii) to test for density dependence in the life cycle. Samples of larvae and downstream‐drifting adults (newly emerged subimagines and spent female imagines) and counts of egg masses were taken every 2 weeks over 39 months in a small stony stream. 2. Although females from the summer generation were smaller than those from the overwintering generation and laid fewer eggs, the relationship between the number of eggs laid by a female and body length was the same for both generations, being described by a power function. An exponential equation described the relationship between the mean body length of each instar and instar number; hence, Dyar’s hypothesis was validated. Adult males emerged after 17 or 18 larval instars and females after 18 or 19 instars in the summer generation, with higher values of 25 or 26 instars for males and 26 or 27 instars for females in the overwintering generation. Mean instar body length in the summer generation was always larger than that in the overwintering generation, but this did not produce larger final instar larvae because the fewer instars resulted in males and females being smaller on emergence than in the overwintering generation. 3. Male subimagines started to emerge before females, and their emergence patterns indicated that there were two cohorts in each generation. Ovipositing females in the first cohort were always larger than those in the second cohort. Therefore, four mean values for eggs/female (=eggs/egg mass) were used to convert egg masses per m2 to eggs laid per m2. Larvae were divided into six stages: I = instar 1, II = instars 2–5, III = instars 6–10, IV = instars 11–16, V = instars 17–24 (overwintering generation only) and VI = final instars prior to emergence. There were two clear modal densities for each larval stage in each generation, confirming the presence of two cohorts. 4. These modal densities were used to estimate loss rates between successive larval stages, and ‘k‐factor analysis’ was used to examine the relationship between loss rates for a particular larval stage and the modal value for eggs or larvae at the start of that stage. Loss rates in larval stage II were density dependent and were when population regulation occurred. For all other larval stages, loss rates were density independent and fairly constant with no significant differences between the two generations. Life tables were constructed for egg densities close to the range of modal values found in the stream (1332–11 512 m−2). The egg density that yielded the maximum number of final instar larvae, and hence adults, was 2700–2750 m−2 with poorer survival for initial egg densities below and above these values. 5. This study has shown that (i) the mechanism for population re...

show abstract

Etude expérimentale de Tincubation des oeufs de Baetis rhodani Pictet

Cited by 22 publications

References 6 publications

Environmental constraints on oviposition limit egg supply of a stream insect at multiple scales

Environmental constraints on oviposition limit egg supply of a stream insect at multiple scales

Life History Strategies in Ephemeroptera and Plecoptera

Contrasting dynamics from egg to adult in the life cycle of summer and overwintering generations ofBaetis rhodaniin a small stream

Contact Info

Product

Resources

About