Effect of salinity on the osmoregulatory cells in the tracheal gills of the stonefly nymph, <i>Paragnetina media</i> (Plecoptera: Perlidae)

Kapoor, N. N.

doi:10.1139/z78-350

Cited by 17 publications

(12 citation statements)

References 7 publications

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“…Ion regulation was disrupted by damage to the osmoregulatory cells of nymphs exposed to pH 2 .5, and subtle changes occurred in osmoregulatory cells of nymphs exposed to pH 4 .0 . Kapoor (1978) found that similar changes in ion content occurred in plecopteran nymphs exposed to a hypertonic, 1 .2% sodium chloride solution . Similarly, ionoregulation imbalance probably occurred in damselfly nymphs at pH 3 .5 in our study.…”

Section: Predation By Nymphs Cultured In Pond Water Vs Rswmentioning

confidence: 65%

Effects of acidic pH on predation rates and survivorship of damselfly nymphs

Gorham

Vodopich

1992

Hydrobiologia

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Environmental variables such as pH critically affect the physiology and ecology of aquatic organisms . Our lack of information regarding indirect effects of acid precipitation requires investigation of acid stress and response to acid stress by species of freshwater communities . Damselfly nymphs Enallagma civile (Odonata: Coenagrionidae) are abundant aquatic predators and food items for other secondary consumers.We investigated the effects of low pH on mortality, survivorship, predation rate, respiration rate, and caloric content of nymphs of E . civile . We hypothesized that acid stress would increase mortality and decrease predation rate among surviving individuals . We hypothesized that respiration rate and caloric content as measures of physiological condition would decrease in acid-stress conditions .We cultured individual early-instar nymphs in the laboratory with a controlled diet of mosquito larvae . The nymphs were reared to final instar in pond water and artificially reconstituted soft water (RSW) adjusted to pH 3 .5, 4 .5, 5 .5, and ambient conditions of the collection site .Predation rate was significantly lower in RSW than in pond water in treatments of equivalent H + concentrations . This indicated stress from differences in dissolved solids in RSW compared with pond water. Acid conditions significantly affected predation rates in pond water, but only at pH 3 .5 and only for the largest instar . Mortality increased and survivorship decreased at low pH . Early-in star mortality and survivorship were particularly susceptible to acid stress . Treatments of pH 4 .5, 5 .5 and ambient did not significantly alter respiration rate or caloric content . However, respiration rate and caloric content increased at pH 3 .5 .Damselfly nymphs tolerated pHs as low as 4 .5 without significant changes (including predation rate) . However, the effects of pH 3 .5 were significant and greatly lowered the predation and fitness of the nymphs .

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Section: Predation By Nymphs Cultured In Pond Water Vs Rswmentioning

confidence: 65%

Effects of acidic pH on predation rates and survivorship of damselfly nymphs

Gorham

Vodopich

1992

Hydrobiologia

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“…This group was largely composed of small ephemeral pools associated with old trackways on the Lizard, which are characterised by relatively high conductivities due to their mineral substrate being derived from serpentine bedrock (see Bilton et al, 2009). The influence of conductivity on macroinvertebrate community composition and diversity is well documented (Kapoor, 1978;Lemly, 1982;Williams et al, 1997;Williams and Williams, 1998;Blasius and Merritt, 2002;Biggs et al, 2005;De Jonge et al, 2008), and at low values, the vast majority of studies document a positive relationship between conductivity and species richness. Very high conductivities are associated with a decline in the diversity of freshwater macroinvertebrates, this operating largely through the osmotic challenges of high ion concentrations (Macan, 1974;Blasius and Merritt, 2002).…”

Section: Discussionmentioning

confidence: 99%

A heuristic approach to predicting water beetle diversity in temporary and fluctuating waters

Gutiérrez‐Estrada

Bilton

2010

Ecological Modelling

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a b s t r a c tAn understanding of the causal mechanisms and processes that shape macroinvertebrate communities at a local scale has important implications for the management and conservation of freshwater biodiversity. Here we compare the performance of linear and non-linear statistics to explore diversity-environment relationships using data from 76 temporary and fluctuating ponds in two regions of southern England. We focus on aquatic beetle assemblages, which have been shown to be excellent surrogates of wider freshwater macroinvertebrate diversity. Ponds in the region contained a rich coleopteran fauna, totaling 68 species, which provided an excellent model system with which to compare the performance of two nonlinear procedures (artificial neural networks-ANNs and generalised additive models-GAMs) and one more traditional linear approach (Multiple linear regression-MLR) to modelling diversity-environment relationships. Of all approaches employed, the best fit was obtained using an ANN model with only four input variables (conductivity, turbidity, magnesium concentration and depth). This model accounted for 82% of the observed variability in Shannon diversity index across ponds. In contrast, the best GAM and MLR models only explained 50% and 14% of this variation, respectively. Contribution profile analysis of conductivity, turbidity, magnesium concentration and depth, obtained from the best fit ANN through a hierarchical cluster analysis, allowed the identification of direct and proxy effects in relation to the environmental variables measured in this study. In each case, distinct clusters of ponds were identified in contribution profile analysis, suggesting that ponds across the two regions fall into a number of discrete groups, whose beetle faunas respond in subtly yet significantly different ways to key environmental variables. Aquatic coleopteran diversity in ponds in the two regions appears to be driven at a local scale by changes in relatively few physicochemical gradients, which are related to diversity in a clearly non-linear manner.

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“…The three-dimensional SEM images were related to the two-dimensional images of thin sections from the proximal, middle, and distal regions of the tubule. All material for both SEM and transmission electron microscopy (TEM) was fixed in 2.5% glutaraldehyde in phosphate buffer (pH 7.1 ) and postfixed in 1 % osmium tetroxide (Kapoor 1978). For SEM, critical-point-dried Malpighian tubules, both whole and fractured in different planes, were mounted on stubs and coated with about 100 A ( 1 A = 0.1 nm) of gold.…”

Section: Methodsmentioning

confidence: 99%

“…The present study was undertaken to invesOsmoregulatory mechanisms in the stoneflies (Plecoptera) figate the stmctural details and cell types of the Malpighian are of interest, as the majority spend most of their life in fresh in this !jtonefly water. The 300 mosmol/L osmotic concentration of the hemolymph of nymphs of Paragnetina media is extremely hyperosmotic with respect to fresh water (Kapoor 1978). These nymphs are faced with the problems of ion losses to the surrounding water and dilution of the body fluids because of continual diffusion of water through the body surface.…”

Section: Introductionmentioning

confidence: 99%

A study of the Malpighian tubules of the plecopteran nymph Paragnetina media (Walker) (Plecoptera: Perlidae) by light, scanning electron, and transmission electron microscopy

Kapoor¹

1994

Can. J. Zool.

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The present study concerns the structural details of the Malpighian tubules in the nymph of the stonefly Paragnetina media. There is no external segmentation except for a distal short hyaline segment. The tubules are composed of two cell types: primary and stellate. Primary cells in the proximal and middle portions of the tubule have short infoldings of the basal membrane and the cytosol is packed with laminate spheres. Cells of the distal segment possess long and tightly packed membrane folds but are devoid of laminate spheres. The stellate cells are sparsely distributed in the middle region and make up 12% of the total cell population in the Malpighian tubule; they lack laminate spheres. Long processes of the stellate cells extend between adjacent primary cells to the luminal and outer surfaces of the tubule.

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Effect of salinity on the osmoregulatory cells in the tracheal gills of the stonefly nymph, Paragnetina media (Plecoptera: Perlidae)

Cited by 17 publications

References 7 publications

Effects of acidic pH on predation rates and survivorship of damselfly nymphs

Effects of acidic pH on predation rates and survivorship of damselfly nymphs

A heuristic approach to predicting water beetle diversity in temporary and fluctuating waters

A study of the Malpighian tubules of the plecopteran nymph Paragnetina media (Walker) (Plecoptera: Perlidae) by light, scanning electron, and transmission electron microscopy

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