Chydorus ‘mutilus’ Kreis, 1921 — a postephippial form of Chydorus sphaericus (O. F. Müller, 1785)

Brancelj, Anton

doi:10.1007/bf00020546

Cited by 6 publications

(2 citation statements)

References 9 publications

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“…Although Frey (1980: Plate III, 13–17) showed some variation in the male hooks, we think that the apical morphology and the width of the furrows may be species‐specific. In other, closely related species (see figures in Frey, 1980; Brancelj, 1987; Floessner, 2000), the clasper tips are different. This may help to prevent interspecies crosses.…”

Section: Discussionmentioning

confidence: 99%

Sex in a cyclical parthenogen: mating behaviour of Chydorus sphaericus (Crustacea; Branchiopoda; Anomopoda)

Damme

Dumont

2006

Freshwater Biology

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1. We describe the interactions during mating in Chydorus sphaericus, a cyclical parthenogenetic anomopod. Mating behaviour is more complex than previously assumed, with evidence for a diffusible chemical to which males react at the onset of mating, for reproductive isolation, and for postcopulatory mate guarding. 2. During mating, the male and female form a 'mating cross' that may be maintained for several hours, while copulation itself typically lasts less than a minute. Furthermore, males invariably attach to the right valve of females. Copulation involves intromission of the postabdomen between the valves, so that the gonopores approach the left ovarium. 3. This behaviour is reflected in the morphology of both sexes: males have a specialised anterior valve margin, postabdomen, first limb and rostrum, under selective pressure for successful mate guarding and copulation, while gamogenetic females have asymmetric ovaries, and a species-specific setulation of the valves. Males of the structurally related Chydorus ovalis react to the presence of C. sphaericus, but fail to dock to females, suggesting a lock-antilock element in the reproductive isolation of both species. 4. The morphological and ethological adaptations in C. sphaericus suggest that there is a strong selective pressure on mating behaviour in this cyclical parthenogen and specifically towards the formation of the 'mating cross'.

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Section: Discussionmentioning

confidence: 99%

Sex in a cyclical parthenogen: mating behaviour of Chydorus sphaericus (Crustacea; Branchiopoda; Anomopoda)

Damme

Dumont

2006

Freshwater Biology

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“…The frequency of A. affinis increases particularly strongly between 9.5 and 5.0 cm (representing the period between 1940 and 1955), and between 3.5 and 1.8 cm (1965 -1980). A hump-backed form of C. sphaericus, a special ecophenotype and an indicator of lowtemperature environments (Brancelj 1996), was consistently present, but at low frequencies.…”

Section: Cladoceramentioning

confidence: 96%

Changes in the trophic level of an Alpine lake, Jezero v Ledvici (NW Slovenia), induced by earthquakes and climate change

Brancelj¹,

Šiško²,

Lami³

et al. 2000

J Limnol

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Despite relatively high nutrient levels, the Slovenian Alpine lake Jezero v Ledvici (1824 m a.s.l.; max. depth 15 m) is oligotrophic, with high transparency and low chlorophyll concentrations (<1 μg l-1). Daily mean air temperatures at the lake are estimated to vary between –15.4 °C and +18.8 °C. Low air temperatures combined with the blocking of incident solar radiation by the local topography result in the lake being ice-covered for over six months of the year, suggesting that the effects of climate on the ecology of the lake may be mediated by the timing of the ice cover. Sediment cores taken in 1996 were dated by 210Pb and 137Cs and analysed for DW, LOI, cladoceran and diatom remains, pigments, C, N and S. A total of 50 diatom taxa and 4 cladoceran taxa were found. The base of the unsupported 210Pb record at 17.4 cm was dated to 1825 AD ± 25 y. An abrupt change in DW and LOI was observed at a depth of 17 cm, coinciding with a change in the cladoceran community and in C and N concentrations. From a depth of 12 cm (83 ± 4 y BP) upward, a sharp change in S and plant pigment concentrations were recorded, followed by an increase in diatom abundance at a depth of about 10 cm (63 ± 4 y BP). The timing of quantitative changes in the physical and chemical properties of the sediment, and in the community structure of diatoms and Cladocera, coincides with the occurrence of three earthquakes in the 19th century. Changes in the diatom and cladoceran record were compared with a tree-ring width index based on Larix decidua from the shore of the lake over the last 136 years, and with reconstructed air temperatures from 1781 – 1996. With a 4-y lag, a weak positive correlation exists between the tree-ring width index and the air temperatures. Although diatom abundance generally shows no correlation with the tree-ring width index, a negative correlation was found in the case of Fragilaria pinnata and Amphora lybica, interrupted only between 1942 and 1955. A similar pattern to this latter was also observed in the case of the Cladocera. During the last 250 y, anthropogenic influence on the lake catchment area has been confined mainly to limited sheep grazing. The main cause of changes occurring in the lake itself is likely to be eutrophication resulting from the input of allochthonous material from landslides triggered by earthquakes. During the last three decades, however, the main factor influencing biotic change appears to have been the increase in mean air temperature, possibly acting via ice cover

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Cryptic species within the Chydorus sphaericus species complex (Crustacea: Cladocera) revealed by molecular markers and sexual stage morphology

Belyaeva

Taylor

2009

Molecular Phylogenetics and Evolution

116

107

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Chydorus ‘mutilus’ Kreis, 1921 — a postephippial form of Chydorus sphaericus (O. F. Müller, 1785)

Cited by 6 publications

References 9 publications

Sex in a cyclical parthenogen: mating behaviour of Chydorus sphaericus (Crustacea; Branchiopoda; Anomopoda)

Sex in a cyclical parthenogen: mating behaviour of Chydorus sphaericus (Crustacea; Branchiopoda; Anomopoda)

Changes in the trophic level of an Alpine lake, Jezero v Ledvici (NW Slovenia), induced by earthquakes and climate change

Cryptic species within the Chydorus sphaericus species complex (Crustacea: Cladocera) revealed by molecular markers and sexual stage morphology

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