Morphological Variation of Keratella cochlearis (Gosse) in a Backwater of the River Thames

Green, Jim

doi:10.1007/s10750-005-4121-6

Cited by 20 publications

(16 citation statements)

References 11 publications

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“…This was most obvious in Taungtaman, where the unspined forms were an average of 4.8 mm longer. A re-examination of the sample, including measurement of a further 70 spineless forms confirmed this difference, and revealed that the loricas had rounded posterior ends similar to the larger of the two forms found by Green (2005) in the River Thames. This form (aspina) occurred through much of the year and was regarded as distinct from the true tecta.…”

Section: Forms Without Posterior Spinesmentioning

confidence: 69%

“…A negative correlation between water temperature and spine length has been demonstrated (Eloranta, 1982;Bielanska-Grajner, 1995;Green, 2005). An interesting correlation of this, is the finding by Hillbricht-Ilkowska (1972) that in a deep lake the individuals of K. cochlearis in the cool meta-and hypolimnion were larger and had longer spines than those in the warm epilimnion.…”

Section: Introductionmentioning

confidence: 80%

“…Figure 5 shows the relationship between spine length and lorica length in the River Thames (data from Green, 2005) and some Cumbrian lakes (J. Green, unpublished), compared with the Myanmar data.…”

Section: Discussionmentioning

confidence: 99%

“…The course of seasonal variation produces shorter spines, and eventually tecta, during the summer months, but there are many oligotrophic lakes in which tecta does not occur. Green (2005) has shown that in a backwater of the River Thames there is a form without a posterior spine (aspina) present for most of the year, which can be distinguished from the tecta form sensu stricto, by its large size and more rounded posterior end.…”

Section: Introductionmentioning

confidence: 99%

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Morphological variation of Keratella cochlearis (Gosse) in Myanmar (Burma) in relation to zooplankton community structure

Green

2007

Hydrobiologia

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Keratella cochlearis was present in 27 of 35 water bodies sampled in Myanmar, and was the most abundant rotifer in 10. Measurements of lorica length and posterior spine length from 20 localities showed that posterior spine length varied both with lorica length and with the composition of the crustacean zooplankton. Long spines were associated with dominance by Heliodiaptomus. The shortest spines were found in samples dominated by cladocerans or cyclopoid copepods. Posterior spine length was positively correlated with the number of diaptomid copepods. Forms without posterior spines were found in 17 localities. The lorica lengths of these spineless forms were generally similar to those of co-occurring spined forms (r = 0.68), but in a few samples the loricas of the spineless forms were significantly larger. These larger forms are similar to the 'aspina' forms recently recognised in the River Thames in England. These samples were dominated by cladocerans or cyclopoid copepods. In one locality spineless forms were found without spined forms. The crustacean zooplankton in this locality was also dominated by cladocerans.

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Section: Forms Without Posterior Spinesmentioning

confidence: 69%

Section: Introductionmentioning

confidence: 80%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Morphological variation of Keratella cochlearis (Gosse) in Myanmar (Burma) in relation to zooplankton community structure

Green

2007

Hydrobiologia

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“…The lengthening of posterior spines increases the buoyancy of Keratella and helps them stay in the phototrophic zone with abundant food resource (Green 2005), moreover the prolonged posterior spine can also deter the predation by predators (Stemberger and Gilbert 1984). The strong paddles may increase the motility of Polyarthra and allow them to swim more rapidly, which will decrease the relative vulnerability of Polyarthra to predators (Gilbert 1985;Williamson 1987).…”

Section: Introductionmentioning

confidence: 99%

Polymorphism in stem females and successive parthenogenetic generations in Brachionus calyciflorus Pallas

Yin

Niu

2007

Aquat Ecol

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We have described the polymorphism in the hatchlings of resting eggs and the morphological variations between the stem females hatched from resting eggs and their successive parthenogenetic generations in the rotifer Brachionus calyciflorus. We hatched resting eggs of B. calyciflorus in two different culture mediums: unconditioned medium (IOM) and Asplanchna-conditioned (ACM). The hatching rate of resting eggs in IOM and ACM were 32.5% and 28.5%, respectively, and showed no significant difference. Stem females hatching from these resting eggs had three morphotypes (unspined, single short-spined, and two short-spined) and over 80% of these females were spineless ones. Moreover, the frequency of each morphotype stem females showed similar tendency in IOM and ACM. The production of a variety of morphotypes among stem mothers-rather than all unspined as has been previously reported for this species-may be regarded as a form of bet-hedging in this population of B. calyciflorus. Phenotypic changes in morphology between the stem females hatched from resting eggs and their successive parthenogenetic generations in B. calyciflorus were found. The possible mechanisms, responsible for high proportion of spineless phenotype at early generations from resting eggs and increased spined phenotype in successive parthenogenetic generations, were discussed in the article.

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Seasonal changes in the body size of two rotifer species living in activated sludge follow the Temperature‐Size Rule

Kiełbasa

Walczyńska

Fiałkowska

et al. 2014

Ecology and Evolution

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Temperature-Size Rule (TSR) is a phenotypic body size response of ectotherms to changing temperature. It is known from the laboratory studies, but seasonal patterns in the field were not studied so far. We examined the body size changes in time of rotifers inhabiting activated sludge. We hypothesize that temperature is the most influencing parameter in sludge environment, leading sludge rotifers to seasonally change their body size according to TSR, and that oxygen content also induces the size response. The presence of TSR in Lecane inermis rotifer was tested in a laboratory study with two temperature and two food-type treatments. The effect of interaction between temperature and food was significant; L. inermis followed TSR in one food type only. The seasonal variability in the body sizes of the rotifers L. inermis and Cephalodella gracilis was estimated by monthly sampling and analyzed by multiple regression, in relation to the sludge parameters selected as the most influential by multivariate analysis, and predicted to alter rotifer body size (temperature and oxygen). L. inermis varied significantly in size throughout the year, and this variability is explained by temperature as predicted by the TSR, but not by oxygen availability. C. gracilis also varied in size, though this variability was explained by both temperature and oxygen. We suggest that sludge age acts as a mortality factor in activated sludge. It may have a seasonal effect on the body size of L. inermis and modify a possible effect of oxygen. Activated sludge habitat is driven by both biological processes and human regulation, yet its resident organisms follow general evolutionary rule as they do in other biological systems. The interspecific response patterns differ, revealing the importance of taking species-specific properties into account. Our findings are applicable to sludge properties enhancement through optimizing the conditions for its biological component.

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Morphological Variation of Keratella cochlearis (Gosse) in a Backwater of the River Thames

Cited by 20 publications

References 11 publications

Morphological variation of Keratella cochlearis (Gosse) in Myanmar (Burma) in relation to zooplankton community structure

Morphological variation of Keratella cochlearis (Gosse) in Myanmar (Burma) in relation to zooplankton community structure

Polymorphism in stem females and successive parthenogenetic generations in Brachionus calyciflorus Pallas

Seasonal changes in the body size of two rotifer species living in activated sludge follow the Temperature‐Size Rule

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