Aquatic Insect Larvae Research Articles

Biology of the Sand Roller in the Central Columbia River

Abstract The sand roller, Percopsis transmontana, is endemic to the Columbia River and its tributaries. The species occurs at depths to 4 m over rock and sand bottom at temperatures of 2.5 C in winter to 20.5 C in summer. The fork length (FL, mm)-weight (W, g) relationship of the sand roller is log eW = 10.65 + 2.91 logeFL. Sand rollers attain at least age VI and 103 mm FL. Fish growth is greatest during the first year of life and declines after maturity at age II-III. Spawning occurs in midsummer. Aquatic insect larvae (mainly Diptera and Trichoptera) are the major food items, but crustacean zooplankton constitute a greater portion of the diet of immature fish less than 40 mm FL.

Tolerance and Buoyancy of Aquatic Insect Larvae Exposed to Gas Supersaturated Water 12

Larvae of nonbiting midgeflies, mayflies and caddisflies, and stonefly nymphs were highly tolerant to dissolved gas supersaturation in laboratory bioassays. However, most larvae and nymphs lost some buoyancy control and floated, which could indirectly cause death. The immature insects tested became buoyant when exposed to water containing large quantities of fine air bubbles, simulating conditions that occur in a stilling basin below a dam.

Effets de trois insecticides (Lindane, fenthion et carbaryl): Toxicité aiguë sur quatre espèces d'invertébrés limniques; toxicité chronique chez le mollusque pulmoné Lymnea

Acute toxicity: Lethal concentrations for 50% of the animals (LC50) were established for three insecticides: carbaryl, fenthion and lindane. On the second day LC50 were respectively: 0·029, 0·014 and 0·03 ppm for Gammarus, 0·48, 0·012 and 0·092 ppm for Cloeon, 0·296, 0·012 and 0·008 ppm for Chaoborus and 21, 6·4 and 7·3 ppm for Lymnea. The sensitivity of the crustacean Gammarus is of the same order or higher than that of aquatic insect larvae. On the other hand, the pulmonate Lymnea is clearly more resistant. Chronic toxicity: This study was conducted with Lymnea using carbaryl and lindane. At a concentration of 1 ppm, only carbaryl had any effect on mortality. On the other hand, an evident decrease in the rate of growth from the third month was shown at a 2 ppm concentration of lindane. There is also a clear toxic effect of this insecticide on fecundity (decrease of 36% with 1 ppm, of 66% with 2 ppm), on egg fertility and on embryogenesis (frequency of double and multiple embryos: 11·6% with 1 ppm, 23·5% with 2 ppm).

Life History and Taxonomic Status of an Isolated Population of Arctic Char, Salvelinus alpinus, from Gros Morne National Park, Newfoundland

Landlocked Arctic char, Salvelinus alpinus, from Candlestick Pond, Gros Morne National Park, Newfoundland, were characterized by slow growth, short life span (max 7 yr), and small size (max fork length = 164 mm). Sexual maturity was obtained at age 3, fecundity was low (max 104 ova per fish), and spawning annual. Major food items were zooplankton and aquatic insect larvae. Eight morphometric and eight meristic characters were examined and compared with available literature data for nonanadromous S. alpinus in eastern North America. Arctic char from Candlestick Pond were not significantly different from S. alpinus oquassa from Quebec and Maine but were significantly different from char from Labrador and other locations in insular Newfoundland. It is proposed that Arctic char from Candlestick Pond are descendents of an aboriginal form of S. alpinus that has been largely displaced along the Atlantic coast of North America. Key words: Salvelinus alpinus, Newfoundland, life history, taxonomic status

Substrate Attachment by Drifting Aquatic Insect Larvae

A series of laboratory experiments was designed to evaluate sediment type and illumination as factors affecting substrate attachment by 3 species of drifting aquatic insect larvae. Stone or cobble sediment patches with (natural) or without (sterile) an epilithic food resource were placed in artificial stream channels. Larvae of Stenacron interpunctatum (Ephemeroptera), Acroneuria abnormis (Plecoptera), and Chimarra aterrima (Trichoptera) were drifted over these patches. Attachment was partitioned into (1) settling and (2) failure to return to the drift (delayed drift). Significant sediment effects on settling were observed with S. interpunctatum and C. aterrima, for the former only during daylight. For all 3 species, significantly fewer animals settled in darkness. Significant delayed drift occurred in both S. interpunctatum and C. aterimma, but only in darkness, off sterile sediments, for the former. These results suggest that invertebrate drift may function as a direct, one—way link between substrate specific faunal associations. A similar experiment tested the effect of a predator (A. abnormis) on substrate attachment by drifting prey (S. interpunctatum). No predator effect was observed on either settling or delayed drift of the prey. Repeating the first series of experiments with killed animals allowed an evaluation of the relative importance of behavior and morphology in substrate attachment. A sediment effect was observed only in A. abnormis, and no settling differences were observed between S. interpunctatum and C. aterrima, species of strikingly different morphology. Killed animals rarely reentered the drift after settling. For these species, settling and delayed drift were much more a function of behavior than of morphology.

Quelques aspects de la biologie du grand corégone Coregonus clupeaformis des lacs Hélène et Nathalie, territoire de la Baie James

The life history of lake whitefish in lakes Nathalie (53°27′ N; 77°27′ W) and Hélène (53°27′ N; 77°31′W) was studied between June 1974 and November 1975. The age of 840 specimens was determined from the scales. Growth rates are very slow, compared only with those of dwarf whitefish of certain North American lakes. Food varies with the length of the fish and with the season of the year. Main food items are aquatic insects (larvae and adults), mollusks, and small fishes. In 1975, spawning occurred in late October (water temperature: 4 °C), at depths of 2–4 m; substrates utilized were sand, gravel, and boulders. Spawning lasted less than 2 weeks. Males mature at 390 mm (age 8) and females at 400 mm (age 9). Lake Nathalie whitefish (N = 41) show a low relative fecundity (17 980 eggs/kg). In the fall of 1974, the population density of Lake Nathalie whitefish 350 mm and longer was estimated at 839 individuals (0.72 kg/ha).

A note on the food of the Australian grayling, Prototroctes maraena Gunther (Galaxioidei: Prototroctidae)

The stomach contents of 22 specimens of the Australian grayling, P. maraena, from the Mitchell River in eastern Victoria were examined. Aquatic insect larvae were predominant; only small amounts of plant material were present. The grayling, like other salmoniforms, is mainly insectivorous.

Distribution and ecology of the Canterbury Mudfish,Neochanna burrowsius(Phillipps) (Salmoniformes: Galaxiidae)

Abstract The present distribution of the rare Canterbury mudfish is described. It is found mainly in man-made or man-modified habitats and is capable of aestivation. It feeds mainly on aquatic insect larvae and crustaceans and is also cannibalistic, eating its own eggs. Spawning occurs in late winter and early spring and appears to be stimuhted by rainfall. The juvenile stage is figured and described, and its pattern of activity compared with that of the adult. The setting up of reserves or the prevention of land modification in muclfish habitats is suggested to ensure the (Con tinuecl survival of the species.

The Insect Pathogenic Fungus Culicinomyces in Mosquitoes and Other Hosts.

Experiments to define the host range of Culicinomyces, a fungus pathogenic to mosquito larvae, indicate that it may be restricted to aquatic larvae of certain families of the Order Diptera. Larvae of the families Culicidae (mosquitoes), Chironomidae (midges) and Ceratopogonidae (biting midges) are susceptible and the course of infection is the same in each. A species of the nematocerous family Psychodidae (moth flies) was insusceptible, as the cellular defence reaction restricted the infection to the invasion site. Several other aquatic insect larvae, as well as atyid shrimps and the mosquito-predaceous fish Gambusia, appeared to be unaffected after prolonged exposure to viable inoculum. The ceratopogonid species had no observable reaction to the pathogen; the chironomid species reacted weakly, which suggests that they may be the normal hosts of Culicinomyces. Mosquitoes reacted strongly to the infection and may be unusual hosts.

Observations on the age, growth, reproduction and food of the roach Rutilus rutilus (L.) in two rivers in southern England

Scales and opercular bones from 632 roach from the River Stour were used for age and back‐calculated growth determinations. The scales had clearer inner annuli but operculars clearer outer annuli in fish more than nine years old. The annuli were laid in late May or early June at the beginning of the growth period. Growth was minimal between November and April. Roach from both rivers grow faster than those in most other European waters. Female roach grow faster than males; River Frome roach faster than those from the Stour. Spawning occurred in May and elaboration of gonads between September and May. Immature roach have an annual cycle in condition with a maximum in June and a minimum in early Spring. The condition of mature females is affected by the gonad cycle. The fecundity of Stour roach is represented by the formula: log egg number=4.43 log length (mm)—1.69. Approximately half of the Stour males attained sexual maturity at age III and most of the rest by age IV. Half of the females were mature at age IV and the remainder by age V. Both brood success and growth rate varied from year to year but independently of one another. Most Stour roach ate aquatic insect larvae and molluscs but algae were more frequent in the diet of larger fish.

A Centrifuge Method for Determining Live Weights of Aquatic Insect Larvae, With a Note on Weight Loss in Preservative

A reproducible centrifuge drying method for determining live or preserved weights of aquatic insect larvae is described. An attempt was made of derive a conversion factor for weight loss in preservative. Results showed a great interspecific variation in weight loss over a period of time due to the effect of preservative.

Studies on a saline lake ecosystem

Saline lakes are in many respects simple natural models of ecosystem structure and function. In this regard, a descriptive study was made of a saline crater lake over 3 years (1968-1970). Lake Werowrap is associated with the Red Rock scoria cone, western Victoria. It is small in area (~21 .6 ha), shallow (~1.4 m), and of variable salinity (23-56 g/l.). The local climate is typically cool temperate, but evaporation exceeds precipitation over most of the year. Meteorological data were used to compute the hydrological and analytical energy budgets for 1969 and 1970. The main determinant of variations in lake salinity and volume was the evaporation/rainfall balance, although groundwater seepage also was implicated. The average rate of water renewal was 0.725 times per year. The annual heat budgets of the lake (mean, 1712 g cal/cm² and the lake sediments (mean, 1218 g cal/cm²) were very small fractions of the total energy fluxes within the system. Energy fluxes were governed mainly by incident radiation, evaporation, back-radiation, and sensible heat transfer. Chemically, the lake water is highly alkaline (pH 9. 8), predominantly of sodium "chlorocarbonate" composition, and showed stable ionic proportions despite salinity fluctuations. Inorganic nitrogen and phosphorus concentrations were high and influenced seasonally by a gull population breeding on a small islet in the lake. Partial information on trace elements was obtained. Optical measurements indicated rapid light attenuation due to dissolved organic material and dense plankton populations. The trophic structure of the ecosystem was taxonomically very simple. The blue-green alga Anabaena spiroides predominated in summer and autumn 1969, but subsequently was displaced by the dinoflagellate Gymnodinium aeruginosum and a blue-green alga tentatively identified as Chroococcus. The change in species composition probably was due to a progressive increase in salinity which occurred during the study. G. aeruginosum, unlike the other species, persisted throughout the seasonal cycle, although changes were observed in the size and structure of the species. Summer and autumn generally were the seasons of most intensive photosynthetic activity. The total phytoplankton production in 1970, measured by the carbon-14 method, was 435 g C/m², evidently the highest figure recorded for any unpolluted lake. Carbon-14 and oxygen productivity data showed good correspondence only in summer, due to effects of non-photosynthetic respiration. Changes in cell and pigment concentrations also were monitored. Radiation and temperature appeared to be the most influential factors governing primary productivity. Inorganic nitrogen was the only chemical constituent to show significant depletion, and may also have been important. Considerable bacterial activity was indicated by high rates of "dark" carbon-14 assimilation. Periphytic productivity, although not measured, was likely to have been significant only in spring 1968. Attention was given to the population dynamics of the rotifer Brachionus plicatilis, the dominant zooplankter, which attained peak densities in summer and autumn. Variations in rotifer population parameters were attributed mainly to salinity, temperature, and food supply. Other zooplankton species included the rotifer Hexarthra jenkinae, two ciliates, and larvae of aquatic and terrestrial insects, notably the dytiscid Necterosoma penicillatum, which occurred around the lake margins. The benthic community consisted solely of the chironomid Tanytarsus barbitarsis. Incomplete productivity data suggest that the lake had the most productive benthic community yet recorded. Caloric measurements for some species in the lake are recorded.

The growth, reproduction and food of the roach Rutilus rutilus (L.), of the River Lugg, Herefordshire

Checks were formed on the scales in June and July. A dominant 1959 year class accounted for half the population present in 1964. Females grew faster than males and attained greater ultimate size. Growth in the River Lugg was good in comparison with rates in other British waters. The sex ratio was found to change with age; a predominance of males in the youngest age classes changed to a preponderance of females in the older classes. The youngest fishes caught (3+) were already sexually mature. The gonads were found to be a constant proportion of the body weight for fishes of all sizes at a given season. Spawning was completed by June; males were ripe in May. The ovaries recovered more rapidly than the testes after spawning. Seasonal variation in feeding activity, with higher activity in summer, was observed and could be correlated with temperature. Seasonal changes in the diet could be related to availability. The diet was predominantly vegetable; the most important animal component, aquatic insect larvae, accounted for 11 % of the total diet. Aerial insects were rarely eaten. Diet varied with age: molluscs being particularly important to older roach; younger roach consumed large amounts of substrate material. There is some evidence that young roach indiscriminately ingest substrate material but older roach are more selective and reject inert material.

Ecological Segregation Between Longnose and Blacknose Dace (Genus Rhinichthys) in the Mink River, Manitoba

Longnose and blacknose dace occur in greatest abundance in the middle zone of the Mink River, and segregation in environment occupied is marked. Newly emerged longnose fry were found in stream margins, but by the middle of their first summer had moved into fast riffles (>45 cm/sec) where they completed their life cycle. Blacknose fry also occupied stream margins, remaining there for up to one year. Thereafter they were found mostly in channels of moderate current. Coexistence of fry of the two species in stream margins is minimized by earlier hatching of longnose dace. Diet of longnose and blacknose dace, consisting of aquatic insect larvae and nymphs, was strikingly similar.

Composition of the Macroinvertebrates Species of the Sasar River

This article analyzes the taxonomic composition of the benthic macroinvertebrates of the Sasar River, located in the north-western part of Romania in a highly industrialized region. Thus, following the systematic study carrie d out during 2003-2006, 41 taxons only were identified. The life of the zoobenthic communi ties, which populate the watercourses, is influenced by the environmental factors (Maxim, 2008) but also by the anthropogenic influence (Malmqvis, 2002). Thus, the toxic impact of inorganic nature of the industry determines the decline of the most sensitive taxons that especially belong to the communities of Ephemeroptera, Plecoptera, and Trichoptera. The bibliographic studies on aquatic insect larvae of the Sasar river are rare, sketchy and tan gential. They mostly come out from the studies and research performed on the Somes River. WORK METHODS . The sampling was performed according to the Normalized Global Biologic Index (NF T 90-350, 1992), during the period of 2003-2006, twice per year. Two sampling stations were set up for the superior sector of the Sasar river (Valea M ariu Ńii and upstream of Baia Sprie), 2 stations for the mid dle sector of the river (downstream of Baia Sprie, upstream of Baia Mare), respectively 1 stati on for the inferior sector of the river (downstream of Baia Mare). RESULTS AND DISCUSSIONS . A good structure of the zoobenthic communities is maintained towards upstream of Baia Sprie. A drasti c deterioration of the studied communities was noticed beginning upstream of the Baia Sprie station. For the Sasar river, the maximum frequencies are fulfilled by Ephemeroptera and Chironomidae (as they appear in all studied stations), and low frequencies were spotted for Trichoptera, Plecoptera, Amphipoda, Coleoptera and Hirudinea. For the Sasar River, the most abundant groups of zoobenthic organisms are: Chironomidae (32%), Oligochaeta (23%). More scarcely are represented the following groups: Ephemeroptera (20%), Trichoptera (10%) and Plecoptera (6%).

Gamma Radiation Effects on Nymphs of the Damselfly Argia translata1

Although considerable work has been done on the effects of radiation on various insects (O'Brien and Wolfe 1964), no study has been found dealing with the effects of gamma radiation on an aquatic species. Howden and Crossley (1961) studied the distribution of adult aquatic insects in the area of a radioactive waste disposal lake, and Peredel'skill and Borgatyrey (1959) studied the scattering of radioisotopes by aquatic insect larvae, but did not report observations on radiation damage to the insects themselves. An initial contribution in this field is presented here.

Seasokal Changes in the Food Ingested by Aquatic Insect Larvae and Nymphs in Two Oregon Streams

Seasokal Changes in the Food Ingested by Aquatic Insect Larvae and Nymphs in Two Oregon Streams

The Effect of Kraft Pulp Mill Wastes on some Aquatic Organisms

Abstract A study has been made of the toxic substances which may be found in kraft pulp-mill waste-waters. It has been determined that the sulphides, mercaptans, resin acid soaps, and sodium hydroxide constitute the greatest hazard. The minimum lethal concentration of these and other materials to fresh-water minnows, Daphnia, and aquatic insect larvae has been established. Methods have been devised for evaluating these materials in kraft-waste waters, and data from the examination of the wastes of a typical northern kraft mill are presented.

The Quantitative Effects of a Dam upon the Bottom Fauna of a Small California Stream

Abstract The effect of a dam upon the bottom-fauna production of Stevens Creek was tested for a 9-month period. The function of this dam being to catch flood waters and subsequently release them gradually, it has reduced the variations in water flow of the rainy season and has brought about a marked change in the physical appearance of the stream bed below the dam. Production of bottom organisms, both in number and weight, was much greater in the area below the dam than above. A sharp, spring peak of production occurred on March 1 in both of the sampling areas. The period of minimum production coincided with the periods of greatest fluctuations in flow and lowest water temperatures. The greatest extremes of flow and temperature took place above the dam. The population above the dam fell to a much lower point during the period of minimum production than did the population below the dam. Three types of aquatic insect larvae formed 81.3 percent of the total number of organisms taken. Caddicefly larvae contri...

Notes on the Food Habits of the Salamanders of Crater Lake, Oregon

C RATER Lake is situated in the caldera of an extinct Pleistocene Volcano, Mount Mazama, of the high Cascade Mountains in southern Oregon. The surface of the lake is 6,177 feet above sea level; the surface area is approximately 21 square miles, and the maximum depth is slightly less than 2,000 feet. In most places at the edge of the lake sheer cliffs or steep talus slopes rise to between 500 and 2,000 feet above the surface. Much of the shoreline consists of irregular wave-washed fragments of andesite, dacite, and to a lesser extent other lava fragments varying in size from a few inches to several feet in diameter. Beneath these fragments, where there is dampness due to wave action, are found the adults of the two species of Crater Lake salamanders, Ambystoma macrodactylum Baird and Triturus granulosus mazamae Myers. The subspecies mazamae is, insofar as now known, endemic to Crater Lake. The adults of the two species occur in approximately equal numbers and apparently in precisely the same daytime habitat since I have found many times individuals of both species under the same rocks. In August, 1946, I collected 56 salamanders for purposes of stomach examinations. Of these, 27 were Ambystoma macrodactylum and 29 were Triturus granulosus mazamae. The identifications were made by Dr. Edward H. Taylor, Museum of Natural History, University of Kansas, in which museum specimens have been deposited. Specimens of both species were almost invariably taken from beneath the same rocks. Of the 27 stomachs from Ambystoma macrodactylum, 19 contained food material. Fourteen of these (74 per cent) contained terrestrial arthropods, almost always in fragments. These were mostly pieces of ants, beetles, and flies. Around and beneath the rocks under which the salamanders were taken I found many fragments of these terrestrial arthropods; entire individuals were rarely found. The stomachs of Triturus granulosus mazamae contain whole individuals of fresh-water amphipods, aquatic arthropods of more delicate nature than the above-mentioned terrestrial arthropods. These fresh-water amphipods are available alive and presumably are taken alive by mazamae. Because of the almost constantly fragmentary nature of the terrestrial arthropods found both in the stomachs and the environment of macrodactylum, and because the more delicate amphipods occur as entire individuals in the stomachs of mazamae, I infer that macrodactylum obtains terrestrial arthropods primarily as fragments by scavenging. Seven stomachs (37 per cent) of Ambystoma macrodactylum contained the larvae of coleopterous, dipterous, and trichopterous aquatic insects, two stomachs held unidentifiable material and one only a fragment of andesite about one centimeter in length. Of the 29 stomachs of Triturus granulosus mazamae examined, there