Distribution of the Stonefly Nymph Paragnetina media (Plecoptera:Perlidae): Influence of Prey, Predators, Current Speed, and Substrate Composition

1986 ◽  
Vol 43 (8) ◽  
pp. 1582-1587 ◽  
Author(s):  
Blair W. Feltmate ◽  
Robert L. Baker ◽  
Philip J. Pointing
Keyword(s):  
Early Spring ◽  
Current Speed ◽  
Interactive Effects ◽  
Salmo Gairdneri ◽  
Substrate Selection ◽  
Laboratory Findings ◽  
Lighting Condition ◽  
Substrate Composition ◽  
Risk Of Predation ◽  
Paragnetina Media

Effects of prey distribution, presence of a predator, current speed, and substrate composition on distribution of the predaceous stonefly nymph Paragnetina media (Walker) were examined in a large laboratory stream. Distribution of prey (Hydropsyche sparna, H. bronta) did not affect distribution of well-fed or non-fed (48 h) nymphs. However, P. media distribution was significantly influenced by independent and interactive effects of current speed (0.33–0.41 m∙s−1) and substrate composition (53.0–110.0 mm in diameter). In the presence of rainbow trout (Salmo gairdneri), P. media selected more specifically for larger substrate on which risk of predation was less than on smaller size classes. Lighting condition had no effect on substrate selection. Laboratory findings were consistent with distribution of P. media observed in the Credit River, Ontario, during midsummer, late fall, and early spring.

Influence of Rainbow Trout (Oncothynchus mykiss) on Density and Feeding Behaviour of a Perlid Stonefly

1989 ◽  
Vol 46 (9) ◽  
pp. 1575-1580 ◽  
Author(s):  
Blair W. Feltmate ◽  
D. Dudley Williams
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Feeding Behaviour ◽  
Predator Avoidance ◽  
Feeding Rate ◽  
Avoidance Behaviour ◽  
Substrate Selection ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Paragnetina Media

Stonefly (Paragnetina media) density was reduced in a rainbow trout (Oncorhynchus mykiss) enclosure by approximately 35%, whereas in a trout exclosure no significant changes in density occurred. Of the 35% reduction, approximately two-fifths and three-fifths were attributable, respectively to direct consumption of stoneflies by trout, and emigration by stoneflies from the predator-stressed section of stream. With trout present in laboratory aquaria, predator avoidance behaviour resulted in stoneflies remaining significantly more on dark substrate on which they were less vulnerable to trout predators. Stoneflies consumed significantly fewer prey (enchytraeid whiteworms) over 24 h, in the presence of both small (2.0–4.0 cm) and large (10.0–12.0 cm) rainbow trout in aquaria, compared with stoneflies feeding in trout-free aquaria. Feeding rate and substrate selection did not differ between well-fed and starved (5 d) nymphs.

Gas Supersaturation as a Cause of Early Spring Mortality of Stocked Trout

1985 ◽  
Vol 42 (2) ◽  
pp. 268-279 ◽  
Author(s):  
Jack A. Mathias ◽  
Jan Barica
Keyword(s):  
Early Spring ◽  
Salmo Gairdneri ◽  
Dissolved Gas ◽  
Lake Volume ◽  
Relative Contribution ◽  
Partial Pressures ◽  
Gas Bubble Disease ◽  
Prairie Lakes ◽  
Algal Photosynthesis ◽  
Oxygen Concentrations

Rainbow trout (Salmo gairdneri) fingerlings, stocked through the ice of shallow prairie lakes, experienced high mortality even though algal photosynthesis had returned whole-lake oxygen concentrations to normal levels prior to ice melting. Fish caged beneath the ice showed symptoms of asphyxiation or gas bubble disease, depending on depth. Asphyxiation occurred at oxygen concentrations below 4 mg/L We identify total dissolved gas tension as the primary cause of bubble disease and resulting mortality, and demonstrate the relative contribution of oxygen and nitrogen to total gas tension. Significant mortalities were associated with oxygen relative partial pressures (gas partial pressure relative to total hydrostatic pressure) exceeding 0.2, but only when accompanied by nitrogen relative partial pressures above 1.1. Total relative gas tension under these circumstances exceeded 1.3. An increase in nitrogen partial pressures over the winter was attributed to the physical freeze-out of nitrogen from the ice in shallow lakes where reduction of lake volume due to ice formation is substantial.

Cycles vitaux de quelques Plécoptères des Laurentides (insectes)

1969 ◽  
Vol 47 (4) ◽  
pp. 483-494 ◽  
Author(s):  
Peter Harper ◽  
Etienne Magnin
Keyword(s):  
Larval Growth ◽  
Seasonal Succession ◽  
Single Species ◽  
Common Species ◽  
Early Spring ◽  
The Other ◽  
Paragnetina Media

Twenty-four species of stoneflies (Plecoptera) were collected in the streams of the Station de Biologie de l'Université de Montréal, at Saint-Hippolyte in Terrebonne county (46°00′ N, 74°00′ W). Sampling of larvae and adults at regular intervals showed the distribution of the species in the stream and the seasonal succession of the adults. The Capniidae and the Taeniopterygidae appear in early spring; the remaining species emerge in May and June. The emergence of a single species Leuctra tenuis extends into July and August. No true autumnal species was found. Larval growth of the more common species is described; these are Taeniopteryx burksi, Paracapnia opis, Isoperla frisoni, Isoperla lata, Hastaperla brevis, and Paragnetina media. Biological notes concerning the other species are included.

Factors Influencing the Microdistribution of Two Sympatric Species of Plecoptera: An Experimental Study

1986 ◽  
Vol 43 (5) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. Dudley Williams
Keyword(s):  
Negative Relationship ◽  
Sympatric Species ◽  
Current Speed ◽  
Skin Mucus ◽  
Significant Negative Relationship ◽  
Beam Interruption ◽  
Substrate Size ◽  
Linear Addition ◽  
Paragnetina Media ◽  
The Relationship

The responses of nymphs of two species of perlid stoneflies to manipulation of some important features of their microhabitats were studied in laboratory stream tanks fitted with an infrared beam interruption system. The activity of both Paragnetina media (Walker) and Phasganophora capitata (Pictet) was significantly affected by current speed and substrate size, and by an interaction between the two. Regression analysis showed that activity for P. capitata was highest at 15 and 75 cm/s and minimal between 25 and 50 cm/s, while that for P. media was highest at 15 cm/s and lowest at 25 cm/s and above. For P. media there was a significant negative relationship between substrate size and activity at a current speed of 15 cm/s. The relationship between the activity of P. capitata and substrate size was not linear. Addition of trout skin mucus to the stream tanks caused an increase in the levels of activity of P. media but a decrease in the activity of P. capitata. Addition of nymphs of the mayfly Ephemerella subvaria to the tank containing P. media produced no effect. These findings suggest mechanisms that establish different microdistributions for sympatric species.

Predator–prey interactions in a stream: a combined field and laboratory study of Paragnetina media (Plecoptera) and Hydropsyche sparna (Trichoptera)

1987 ◽  
Vol 65 (2) ◽  
pp. 448-451 ◽  
Author(s):  
Blair W. Feltmate
Keyword(s):  
Laboratory Study ◽  
Negative Correlation ◽  
Substrate Surface ◽  
Significant Negative Correlation ◽  
Lower Surface ◽  
Laboratory Findings ◽  
Predator Prey ◽  
Surface Colonization ◽  
Substrate Size ◽  
Paragnetina Media

Substrate size selection, upper and lower substrate surface colonization, and net spinning were examined for the caddisfly Hydropsyche sparna in the presence and absence of the predaceous stonefly Paragnetina media. In the laboratory, I found that when stoneflies were present, caddisflies selected larger substrate and spun fewer nets. Upper and lower surface colonization of substrate did not change as a function of P. media presence. Laboratory findings were consistent with observations made of H. sparna and P. media in the Credit River, Ontario, during midsummer 1983. Based on Hess sample collections, I observed a significant negative correlation between stonefly and caddisfly densities.

Role of Rearing Experience in Gravel Substrate Selection by Juvenile Rainbow Trout, Salmo gairdneri

1976 ◽  
Vol 33 (2) ◽  
pp. 282-284 ◽  
Author(s):  
Hugh R. MacCrimmon ◽  
Christopher M. Hawkins
Keyword(s):  
Rainbow Trout ◽  
Statistical Evidence ◽  
Salmo Gairdneri ◽  
Laboratory Studies ◽  
Substrate Selection ◽  
Juvenile Rainbow Trout

Laboratory studies on hatchery-reared wild juvenile rainbow trout (Salmo gairdneri) in an experimental raceway show no significant selection (P < 0.05) of test gravel substrates under either nonflowing or flowing (0.03 m/s) conditions regardless of rearing experience. There is no statistical evidence that hatchery conditioning of rainbow trout for gravel substrate selection is likely to be a feasible undertaking.

Fat adaptation followed by carbohydrate restoration increases AMPK activity in skeletal muscle from trained humans

2008 ◽  
Vol 105 (5) ◽  
pp. 1519-1526 ◽  
Author(s):  
Wee Kian Yeo ◽  
Sarah J. Lessard ◽  
Zhi-Ping Chen ◽  
Andrew P. Garnham ◽  
Louise M. Burke ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Fat Oxidation ◽  
Interactive Effects ◽  
Whole Body ◽  
Substrate Selection ◽  
Downstream Target ◽  
High Carbohydrate ◽  
Resting Muscle ◽  
Muscle Triglyceride

We have previously reported that 5 days of a high-fat diet followed by 1 day of high-carbohydrate intake (Fat-adapt) increased rates of fat oxidation and decreased rates of muscle glycogenolysis during submaximal cycling compared with consumption of an isoenergetic high-carbohydrate diet (HCHO) for 6 days (Burke et al. J Appl Physiol 89: 2413–2421, 2000; Stellingwerff et al. Am J Physiol Endocrinol Metab 290: E380–E388, 2006). To determine potential mechanisms underlying shifts in substrate selection, eight trained subjects performed Fat-adapt and HCHO. On day 7, subjects performed 1-h cycling at 70% peak O2 uptake. Muscle biopsies were taken immediately before and after exercise. Resting muscle glycogen content was similar between treatments, but muscle triglyceride levels were higher after Fat-adapt ( P < 0.05). Resting AMPK-α1 and -α2 activity was higher after Fat-adapt ( P = 0.02 and P = 0.05, respectively), while the phosphorylation of AMPK's downstream target, acetyl-CoA carboxylase (pACC at Ser221), tended to be elevated after Fat-adapt ( P = 0.09). Both the respiratory exchange ratio ( P < 0.01) and muscle glycogen utilization ( P < 0.05) were lower during exercise after Fat-adapt. Exercise increased AMPK-α1 activity after HCHO ( P = 0.03) but not Fat-adapt. Exercise was associated with an increase in pACC at Ser221 for both dietary treatments ( P < 0.05), with postexercise pACC Ser221 higher after Fat-adapt ( P = 0.02). In conclusion, compared with HCHO, Fat-adapt increased resting muscle triglyceride stores and resting AMPK-α1 and -α2 activity. Fat-adapt also resulted in higher rates of whole body fat oxidation, reduced muscle glycogenolysis, and attenuated the exercise-induced rise in AMPK-α1 and AMPK-α2 activity compared with HCHO. Our results demonstrate that AMPK-α1 and AMPK-α2 activity and fuel selection in skeletal muscle in response to exercise can be manipulated by diet and/or the interactive effects of diet and exercise training.

scholarly journals Artificial light on water attracts turtle hatchlings during their near shore transit

2016 ◽  
Vol 3 (5) ◽  
pp. 160142 ◽  
Author(s):  
Michele Thums ◽  
Scott D. Whiting ◽  
Julia Reisser ◽  
Kellie L. Pendoley ◽  
Charitha B. Pattiaratchi ◽  
...  
Keyword(s):  
Chelonia Mydas ◽  
Sea Turtle ◽  
Current Speed ◽  
Artificial Light ◽  
Ambient Conditions ◽  
Experimental Protocol ◽  
Action Current ◽  
Artificial Lighting ◽  
Risk Of Predation ◽  
Near Shore

We examined the effect of artificial light on the near shore trajectories of turtle hatchlings dispersing from natal beaches. Green turtle ( Chelonia mydas ) hatchlings were tagged with miniature acoustic transmitters and their movements tracked within an underwater array of 36 acoustic receivers placed in the near shore zone. A total of 40 hatchlings were tracked, 20 of which were subjected to artificial light during their transit of the array. At the same time, we measured current speed and direction, which were highly variable within and between experimental nights and treatments. Artificial lighting affected hatchling behaviour, with 88% of individual trajectories oriented towards the light and spending, on average, 23% more time in the 2.25 ha tracking array (19.5 ± 5 min) than under ambient light conditions (15.8 ± 5 min). Current speed had little to no effect on the bearing (angular direction) of the hatchling tracks when artificial light was present, but under ambient conditions it influenced the bearing of the tracks when current direction was offshore and above speeds of approximately 32.5 cm s −1 . This is the first experimental evidence that wild turtle hatchlings are attracted to artificial light after entering the ocean, a behaviour that is likely to subject them to greater risk of predation. The experimental protocol described in this study can be used to assess the effect of anthropogenic (light pollution, noise, etc.) and natural (wave action, current, wind, moonlight) influences on the in-water movements of sea turtle hatchlings during the early phase of dispersal.

Effect of habitable space on substrate selection by Paragnetina media (Walker) (Plecoptera: Perlidae)

Hydrobiologia ◽  
1986 ◽  
Vol 131 (3) ◽  
pp. 277-279 ◽  
Author(s):  
Blair W. Feltmate ◽  
Philip J. Pointing
Keyword(s):  
Substrate Selection ◽  
Paragnetina Media

scholarly journals The effects of prolonged epinephrine infusion on the physiology of the rainbow trout, Salmo gairdneri. III. Renal ionic fluxes

1987 ◽  
Vol 128 (1) ◽  
pp. 269-285
Author(s):  
M. G. Vermette ◽  
S. F. Perry
Keyword(s):  
Rainbow Trout ◽  
Interactive Effects ◽  
Salmo Gairdneri ◽  
Epinephrine Infusion ◽  
Bicarbonate Ions ◽  
Ionic Fluxes ◽  
Circulating Levels ◽  
Fish Kidney ◽  
Stimulation Of

Rainbow trout were infused continuously for 24 h with epinephrine in order to evaluate the effects of elevated circulating levels of epinephrine on selected renal variables. Pronounced effects of epinephrine included elevation of urine flow rate and concomitant increases in the excretion of all measured electrolytes (Na+, Cl-, K+, Ca2+, inorganic phosphate) with the exception of ammonium and bicarbonate ions. Significant reductions in the tubular reabsorption of Na+ and Cl- also contributed to enhanced excretion of these ions. Similarly, epinephrine affected the tubular handling of NH4+ and HCO3- with NH4+ secretion decreasing and HCO3- reabsorption increasing. We speculate that the stimulation of HCO3- reabsorption was a consequence of elevated tubular H+ secretion. Such a mechanism may be important to permit plasma HCO3- retention during periods of internal acidosis. The results are discussed with reference to the role of the fish kidney in regulating acid-base disturbances and the possible interactive effects of elevated epinephrine.

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