Patterns of dispersion of aquatic insects colonizing artificial substrates in a southern Ontario stream

1995 ◽  
Vol 73 (3) ◽  
pp. 458-468 ◽  
Author(s):  
Jane E. Rutherford
Keyword(s):  
Aquatic Insects ◽  
Narrow Band ◽  
Artificial Substrates ◽  
Artificial Turf ◽  
Stream Invertebrates ◽  
Southern Ontario ◽  
Competition For Space

Modified artificial turf substrates were readily colonized by stream invertebrates, supporting 20 or more taxa after 10 or 22 days in the stream. Of the individuals present, 50–80% belonged to four taxa: Hydropsychidae, Hydroptila sp. (larvae and pupae), Rheotanytarsus sp., and Baetidae. All four taxa displayed significantly aggregated patterns of dispersion (as shown by Clark–Evans–Donnelly indices) on most of the 6 substrates. The hydropsychids and the Hydroptila sp. pupae appeared to have the highest degree of aggregation, especially at high densities; both taxa occupied about the same areas on the substrates, forming discrete bands of occupation at the upstream and downstream edges as well as along a narrow band near the middle of the substrates. Weakly positive (but generally nonsignificant) Φ2 values (intertaxon association indices based on presence–absence data) coupled with negative Iai values (intertaxon association indices based on joint abundances) for the Hydropsychidae – Rheotanytarsus sp. and Hydroptila sp. – Rheotanytarsus sp. pairings indicate that Rheotanytarsus sp. occupies quite different areas of the substrates than either the hydropsychids or Hydroptila sp. pupae, suggesting that competition for space may be important amongst these sessile taxa.

HIGH-DOSAGE TREATMENT OF A QUEBEC STREAM WITH BACILLUS THURINGIENSIS SEROVAR. ISRAELENSIS: EFFICACY AGAINST BLACK FLY LARVAE (DIPTERA: SIMULIIDAE) AND IMPACT ON NON-TARGET INSECTS

1985 ◽  
Vol 117 (12) ◽  
pp. 1523-1534 ◽  
Author(s):  
C. Back ◽  
J. Boisvert ◽  
J.O. Lacoursière ◽  
G. Charpentier
Keyword(s):  
Bacillus Thuringiensis ◽  
Aquatic Insects ◽  
Artificial Substrates ◽  
High Dose ◽  
Artificial Turf ◽  
Insect Larvae ◽  
Commercial Formulation ◽  
Lake Outlet ◽  
Pre Treatment ◽  
Drifting Larvae

AbstractA typical lake outlet of the Canadian Shield was treated for 15 min with a high dose (5.28 g/L s−1 of discharge) of Teknar®, a commercial formulation of Bacillus thuringiensis serovar. israelensis. Efficacy on Simuliidae larvae and impact on non-target aquatic insects of this stream were monitored using drift nets, counting plates, and artificial turf substrates along a 1000-m section downstream of the site of application. Compared with a 4-day pre-treatment average for 12-h sampling periods, drift of Simuliidae increased from 64 to 92 ×, with shorter peaks of 133–184 ×, 2–6 h after treatment. There was no evident drift increase in larvae of Ephemeroptera, Plecoptera, Trichoptera, Chironomidae, or dipterous pupae, but larvae of Blephariceridae (Diptera) were severely affected as their drift was increased by up to 50 × and remained high for 3 days. After 30 h the mortality of Simuliidae on counting plates ranged from 95 to 82% in the first 300 m, with detachment rates of 78.5–46.5%. Densities of non-target insect larvae were not reduced on the artificial substrates, except for 2 genera of Chironomidae (Eukiefferella and Polypedilum) which were reduced 26 to 39% of their original density. Drifting larvae of 1 chironomid genus (Phaenopsectra) also showed symptoms of toxemia by B.t.i. The main impact of the treatment was thus seen in 2 Nematocera families (Chironomidae and Blephariceridae) which were mainly exposed to B.t.i. sedimented on the bottom of the stream or attached to periphyton growing on rocks.

Movements of adult aquatic insects near streams in Southern Ontario

Hydrobiologia ◽  
1981 ◽  
Vol 77 (1) ◽  
pp. 65-69 ◽  
Author(s):  
G. A. Bird ◽  
H. B. N. Hynes
Keyword(s):  
Aquatic Insects ◽  
Southern Ontario ◽  
Adult Aquatic Insects

Variation in the diet of Myotis lucifugus (Chiroptera: Vespertilionidae)

1976 ◽  
Vol 54 (10) ◽  
pp. 1674-1678 ◽  
Author(s):  
J. J. Belwood ◽  
M. B. Fenton
Keyword(s):  
New York ◽  
Nova Scotia ◽  
Aquatic Insects ◽  
Feeding Habits ◽  
Myotis Lucifugus ◽  
Malaise Trap ◽  
Adult Males ◽  
Northern Ontario ◽  
Southern Ontario ◽  
Caddis Flies

By analysis of feces collected from bats in the field, we determined that aquatic insects, particularly chironomid Diptera, made up the major portion of the diet of Myotis lucifugus at sites in southern Ontario, northern New York, and Nova Scotia. The diets of adult males reflected the available insect prey as sampled by a malaise trap, while those of lactating females included proportionally more caddis flies and moths than were present in the malaise trap samples. The diets of subadults of both sexes showed greater variation than those of adults, although chironomids and caddis flies were important components. While we observed the aforementioned pattern at sites in Nova Scotia, northern New York, and southern Ontario, the diets of adult M. lucifugus in northern Ontario were as variable as those of subadults from more southerly areas. We suggest that M. lucifugus is opportunistic in its feeding habits, and that the adults efficiently harvest s warms of aquatic insects, a trait not fully acquired by the young we sampled at the end of August.

An introduced plant is associated with declines in terrestrial arthropods, but no change in stream invertebrates

2019 ◽  
Vol 76 (8) ◽  
pp. 1314-1325
Author(s):  
Hannah L. Riedl ◽  
William H. Clements ◽  
Liba Pejchar
Keyword(s):  
Aquatic Insects ◽  
Riparian Vegetation ◽  
Native Species ◽  
Vegetative Cover ◽  
Arthropod Communities ◽  
Stream Invertebrates ◽  
Terrestrial Arthropods ◽  
Western Colorado ◽  
Vertical Vegetation Structure ◽  
Riverine Systems

Riverine systems often spread non-native species, yet the co-occurring impacts of introduced riparian vegetation on aquatic- and terrestrial-derived resources are unknown. We compared aquatic and terrestrial arthropod communities and their flux into and out of streams in riparian reaches invaded and uninvaded by Robinia neomexicana, a woody plant introduced to a western Colorado watershed. We found that invaded reaches had fewer terrestrial arthropods collected off foliage, conceivably because of the plant’s later leaf-out phenology. Overall, seasonal and annual factors best described terrestrial and aquatic arthropod communities. However, when we evaluated vegetation and stream characteristics in lieu of season and year, we found terrestrial arthropod biomass and richness were negatively related to cover of R. neomexicana and positively related to vegetative cover, forb cover, and vertical vegetation structure. Our results suggest ecosystems respond to landscape variation differently, where directly related food web components (i.e., terrestrial arthropods on introduced vegetation) respond stronger than more distally related constituents (i.e., aquatic insects).

The Nymph of Rhithrogena impersonata (Ephemerida) and a New Closely Related Species from the Same Locality in Southern Ontario

1954 ◽  
Vol 86 (8) ◽  
pp. 348-356 ◽  
Author(s):  
F. P. Ide
Keyword(s):  
New Species ◽  
Related Species ◽  
Aquatic Insects ◽  
The Other ◽  
Closely Related Species ◽  
Nymphal Stage ◽  
Southern Ontario ◽  
Small Collection ◽  
A New Species

Early in the summer of 1951 a small collection of aquatic insects was submitted to the author by J. Goodwin of Toronto, taken from Sheldon Creek in Dufferin County, Ontario. Included were nymphs of two readily distinguishable species of Rithrogena, one having bright red gills and the other hyaline whitish gills, Those with hyaline whitish gills were more abundant and proved to be R. impersonata Mc.D. of which specimens from Baddeck, N.S. and Lachine, P.Q. are in the Canadian National Collection at Ottawa. I have records of this species in both nymphal and adult stages from the Credit River, Peel County, Ontario, where the association of nymph and adult was made, and in the nymphal stage from the Saugeen River in Grey County, Ontario. The nymphs with red gills proved to be those of a new species which, considering genitalic characters, is closely related to R. impersonata.

scholarly journals Trajectories of aquatic insect functional groups along the resistance/resilience axis when facing water flow changes

2021 ◽  
Author(s):  
Bruno Godoy ◽  
Francisco Valente Neto ◽  
Luciano Queiroz ◽  
Luis Holanda ◽  
Fabio Roque ◽  
...  
Keyword(s):  
Water Flow ◽  
Aquatic Insects ◽  
Environmental Changes ◽  
Aquatic Insect ◽  
Aquatic Organisms ◽  
Aquatic Systems ◽  
Artificial Substrates ◽  
Life Strategy ◽  
Dispersal Capacity ◽  
Over Time

1. Understanding how differences in intensity and frequency of hydrological disturbances affect the resistance and resilience of aquatic organisms is key to manage aquatic systems in a fast-changing world. Organisms’ responses to environmental changes can be influenced by different life strategies. Some aquatic organisms have strategies that improve the permanence in aquatic systems, while others use strategies that enhance colonization. 2. Therefore, we carried out a manipulative experiment to understand the resistance/resilience of aquatic insects based on their functional characteristics to hydrological disturbances in streams in the Cerrado hotspot. 3. We placed 200 artificial substrates in five streams and submitted them to changing water flow regimes that differed both in frequency and intensity. Then we observed the response of the aquatic community for 39 days. We used a Hierarchical Bayesian strategy approach to estimate the probabilities of permanence and colonization of each life strategy group (nine groups). 4. We observe that the most intense changes in the water flow tend to affect the permanence of almost all groups. However, this effect was reduced in intensity over time. On the other hand, less frequent disturbances, regardless of intensity, tend to reduce the permanence of most groups of aquatic insects over time. The difference in the effect of disturbance regarding intensity (higher or lower) may be related to a greater dispersal capacity of some groups. 5. These results are worrisome in a scenario of reduced riparian vegetation around streams and with the expectation of precipitation to become more concentrated in shorter periods of time due to climate change in the Cerrado hotspot. Together, these anthropogenic changes tend to increase the effect of runoff on the lotic systems and, consequently, reduces the permanence of many groups of aquatic insects in their habitat, particularly those with traits associated with permanence.

scholarly journals Analysis of the Dynamics of Marine Structures and Species with Criterial Mathematical Models

2021 ◽  
Vol 9 (12) ◽  
pp. 1431
Author(s):  
Aleksandr Zolotnitsky ◽  
Nataliy Sytnik ◽  
Sergei Chernyi ◽  
Natalya Logunova
Keyword(s):  
Mytilus Galloprovincialis ◽  
Average Length ◽  
Unit Length ◽  
Artificial Substrates ◽  
The Black Sea ◽  
Total Production ◽  
Relative Area ◽  
Marine Structures ◽  
Competition For Space ◽  
B Coefficients

The influence of the area of artificial substrates (collectors) on the biological parameters of populations of mussels (Mytilus galloprovincialis Lamarck) during their cultivation in the Black Sea has been investigated. For growing mollusks, four types of collectors were used, with different relative areas (ω), i.e., with different ratios of the substrate area (S) per unit length of the collector (L), which were 0.09, 0.21, 0.34, and 0.55. It was found that, during a 1.5-year cultivation, the density (N, ind./m) and biomass (B, kg/m) change and reach a certain stationary state, determined by the relative area of the substrate. It was shown that, on collectors with a higher value of ω, there was a decrease in the average length (L, mm) and weight (W, g) of the mollusk yield. The Boysen–Jensen method was used to calculate the total production of mollusks (P), elimination (E), and specific production (P/B coefficient) for each type of reservoir, and it was shown that P increased with an increase in the substrate area, while E and P/B coefficients decreased. Based on the analysis of the obtained results, it was concluded that during the cultivation of mussels these parameters are regulated by density-dependent population factors (intraspecific competition) for space (substrate) and food.

Statistical analysis of classification

1966 ◽  
Vol 24 ◽  
pp. 188-189
Author(s):  
T. J. Deeming
Keyword(s):  
Multivariate Analysis ◽  
Statistical Analysis ◽  
Classification Scheme ◽  
Analytical Procedure ◽  
Narrow Band ◽  
Scientific Research ◽  
Maximum Amount ◽  
Amount Of Information

If we make a set of measurements, such as narrow-band or multicolour photo-electric measurements, which are designed to improve a scheme of classification, and in particular if they are designed to extend the number of dimensions of classification, i.e. the number of classification parameters, then some important problems of analytical procedure arise. First, it is important not to reproduce the errors of the classification scheme which we are trying to improve. Second, when trying to extend the number of dimensions of classification we have little or nothing with which to test the validity of the new parameters.Problems similar to these have occurred in other areas of scientific research (notably psychology and education) and the branch of Statistics called Multivariate Analysis has been developed to deal with them. The techniques of this subject are largely unknown to astronomers, but, if carefully applied, they should at the very least ensure that the astronomer gets the maximum amount of information out of his data and does not waste his time looking for information which is not there. More optimistically, these techniques are potentially capable of indicating the number of classification parameters necessary and giving specific formulas for computing them, as well as pinpointing those particular measurements which are most crucial for determining the classification parameters.

Photo-electric Hβ and uvby photometry

1966 ◽  
Vol 24 ◽  
pp. 170-180
Author(s):  
D. L. Crawford
Keyword(s):  
Narrow Band ◽  
Line Strength ◽  
Interference Filter ◽  
B Stars ◽  
Relative Line ◽  
The Mean ◽  
F Stars ◽  
Two Parameters ◽  
Filter Photometry ◽  
The Continuum

Early in the 1950's Strömgren (1, 2, 3, 4, 5) introduced medium to narrow-band interference filter photometry at the McDonald Observatory. He used six interference filters to obtain two parameters of astrophysical interest. These parameters he calledlandc, for line and continuum hydrogen absorption. The first measured empirically the absorption line strength of Hβby means of a filter of half width 35Å centered on Hβand compared to the mean of two filters situated in the continuum near Hβ. The second index measured empirically the Balmer discontinuity by means of a filter situated below the Balmer discontinuity and two above it. He showed that these two indices could accurately predict the spectral type and luminosity of both B stars and A and F stars. He later derived (6) an indexmfrom the same filters. This index was a measure of the relative line blanketing near 4100Å compared to two filters above 4500Å. These three indices confirmed earlier work by many people, including Lindblad and Becker. References to this earlier work and to the systems discussed today can be found in Strömgren's article inBasic Astronomical Data(7).

Southern Hemisphere Seti Survey: Five Years of Project Meta II

1997 ◽  
Vol 161 ◽  
pp. 611-621
Author(s):  
Guillermo A. Lemarchand ◽  
Fernando R. Colomb ◽  
E. Eduardo Hurrell ◽  
Juan Carlos Olalde
Keyword(s):  
Southern Hemisphere ◽  
Scattering Theory ◽  
Galactic Plane ◽  
Narrow Band ◽  
Neutral Hydrogen ◽  
Sky Survey ◽  
Inertial Frames ◽  
Interstellar Scattering ◽  
Extraterrestrial Origin ◽  
Spectral Channels

AbstractProject META II, a full sky survey for artificial narrow-band signals, has been conducted from one of the two 30-m radiotelescopes of the Instituto Argentino de Radioastronomía (IAR). The search was performed near the 1420 Mhz line of neutral hydrogen, using a 8.4 million channels Fourier spectrometer of 0.05 Hz resolution and 400 kHz instantaneous bandwidth. The observing frequency was corrected both for motions with respect to three astronomical inertial frames, and for the effect of Earths rotation, which provides a characteristic changing signature for narrow-band signals of extraterrestrial origin. Among the 2 × 1013spectral channels analyzed, 29 extra-statistical narrow-band events were found, exceeding the average threshold of 1.7 × 10−23Wm−2. The strongest signals that survive culling for terrestrial interference lie in or near the galactic plane. A description of the project META II observing scheme and results is made as well as the possible interpretation of the results using the Cordes-Lazio-Sagan model based in interstellar scattering theory.

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