Freshwater Insects Research Articles

The freshwater insects of Australasia and their affinities

Stream faunas of New Zealand, southeastern Australia and Tasmania are characterized by numerous cool-adapted species of Ephemeroptera, Trichoptera, Plecoptera, Mecoptera and Diptera with southern (austral) affinities. They include a number of amphinotic (= circum-Antarctic) groups with close relatives in South America and their distributions seem best explained in terms of vicariance of an ancestral, Gondwanaland fauna. A second major component of the Australasian freshwater insect fauna has strong Oriental affinities and is thought to represent a more recent element which entered New Guinea, Australia, New Zealand and islands to the east in the last 20 million years. Included in this element are Trichoptera and Diptera with stream-dwelling larvae and Hemiptera, Coleoptera, Diptera and Odonata which mainly occur in standing waters. Mountains and islands formed when the Australian and Asian plates met in the late Cenozoic would have provided dispersal pathways for many of these groups. Colonisation of islands in the Pacific has resulted from early land connections, e.g. elements of the New Caledonian fauna, dispersal by air and most recently by man.

Osmoregulation and ionic balance in Trichocorixa reticulata (Guerin-Meneville)

1. 1. The osmoregulatory abilities of Trichocorixa reticulata (Guerin-Meneville) were investigated by determining the osmotic pressure and Na and K concentrations of hemolymph after acclimation to a wide range of saline media. 2. 2. The hemolymph was osmoregulated within a narrow range up to an external osmolality of 3000 mOs/kg. exhibiting osmotic control far exceeding any previously reported corixid. 3. 3. Na levels were regulated similar to osmotic pressure; K levels were regulated independently. 4. 4. The osmotic permeability coefficient (2.7 × 10 −2 cm/hr) suggests a cuticular permeability similar to that of freshwater insects.

Basic physiological data relative to ionic regulation in two waterbugs: Corixa dentipes (Thoms.) and Corixa punctata (Illig.) (Hemiptera, Heteroptera)

1. 1. Analyses were made of the major ionic composition of the haemolymph in two adult freshwater insects: Corixa dentipes (Thoms.) and Corixa punctata (Illig.). 2. 2. In both species, the ionic concentration is maintained against a steep concentration gradient with respect to the external medium. 3. 3. The ionic concentration is very similar in both species. 4. 4. The sodium content in different compartments (whole body, haemolymph, tissue) is calculated for C. dentipes and is compared with data for other freshwater insects. 5. 5. Total haemolymph content was measured in both species using a 198Au dilution method.

SUCCESSFUL REARING OF CENOCORIXA EXPLETA (HEMIPTERA: CORIXIDAE) IN FRESH WATER

The water boatman Cenocorixa expleta (Uhler) is an inhabitant of saline ponds in the interior of western North America (Jansson 1972; Scudder 1976). In a field survey, Scudder (1969a) failed to find this species in ponds with surface conductivities less than 3900 μmhos/cm. Although it is apparently absent from fresh water, the osmotic responses of C. expleta are essentially those of a fresh water insect (Scudder et al. 1972). Also, salinity tolerance experiments carried out by Scudder (1969b) show that at 15°C adults of the species can survive almost a month in fresh water (less than 800 μmhos/cm) without food. However, it has not been shown that C. expleta can actually develop and breed successfully in fresh water.

The temperature of two welsh lakes and its effect on the distribution of two freshwater insects

Temperature data are presented from the littoral zones of two lakes in North Wales, Llyn Coron and Llyn Dinas. Recording, mainly on a continuous basis, was over a two year period. Despite their different situations, the lakes had similar temperature regimes. Regional weather factors were of greater importance than local variations. However, some differences were present, especially during the summer months. Laboratory experiments were conducted to determine the temperature relationships of Nemoura avicularis Morton (Plecoptera) and Leptophlebia vespertina (L.) (Ephemeroptera), common species in Llyn Dinas but absent from Llyn Coron. Aspects considered included nymphal temperature tolerance and the effect of temperature on egg development and emergence. From the background of the results, it was concluded that the differences in temperature regime between the two lakes were insufficient to explain the absence of the two species from Llyn Coron.

Factors Influencing Cannibalism, a Mechanism of Population Limitation in the Predator Notonecta hoffmanni

Factors influencing cannibalism rates in the freshwater insect predator Notonecta hoffmanni were analyzed in a series of field and laboratory experiments. Starvation was rejected as a cause of nymphal mortality. Cannibalism was related to both the relative and absolute abundances of alternative food, the cannibal's age, and the presence of refuges for the vulnerable nymphs, although the predator's state of hunger also influenced cannibalism rates. Cannibalism occurred when there was physical proximity between different age—classes even if alternative food were abundant. Long—term feeding history had no effect on cannibalism, which is a rapid response to rapid response to immediate food availibility. The population consequences of cannibalism seem analogous to those of dominance and spacing behavior, causing a decline in population size before animals are actually killed by the limiting resource, and increasing the chances that at least some relatively well—fed individuals will survive and reproduce successfully.

The permeability to water of the cuticle of the larva of Opifex fuscus (Hutton) (Diptera, Culicidae).

ABSTRACT Fourth-instar larvae of Opifex fuscus were found to have a mean body weight of 7·61 mg, a water content of 85·2%, and a mean cuticular surface area of 29·3 mm2. Larvae ligatured at neck and anus were found to lose 1 % of the body weight per hour when immersed in sea water. The osmotic permeability coefficient of the cuticle was calculated from these data to be 2·4 × 10− 2 cm. h− 1. Measurement of the diffusional permeability coefficient (Pd) by means of tritiated water and Deuterium oxide gave a value for this parameter of 4·8 × 10− 3 cm.h− 1. The diffusional permeability of the cuticle of Opifex fuscus is thus less than that of typical freshwater insects, as predicted by Shaw & Stobbart.

Osmotic and ionic balance in two species of Cenocorixa (Hemiptera)

Two species of Cenocorixa occur in central British Columbia, C. bifida in waters with conductivities from 27 to 20,000 μ-mhos/cm and C. expleta in waters with conductivities between 5000 and 30,000 μ-mhos/cm. The osmotic and ionic balances of the two species in various concentrations of a single lake water are similar: the response is that of a typical fresh-water insect. Neither species is able to hyporegulate in the higher salinities and neither is able to produce hyperosmotic urine. Marked mortality occurs when the haemolymph osmotic response curve crosses the isosmotic line: this is at Δ E 0·90°C for C. bifida and Δ E 1·22°C for C. expleta. A difference in their physiological tolerances seems to be the factor determining the differential distribution of the two species in saline waters. C. expleta can survive in low salinities, although it does not naturally occur in fresh water. Ecological interactions with C. bifida would seem to be important in excluding C. expleta from fresh-water habitats.

Larvae of two fresh water insects, Himalopsyche japonica and Neohapalothrix kanii

Larvae of two fresh water insects, Himalopsyche japonica and Neohapalothrix kanii

BRAZILIAN CHYTRIDS. VI. RHOPALOPHLYCTIS AND CHYTRIOMYCES, TWO NEW CHITINOPHYLLIC OPERCULATE GENERA

BRAZILIAN CHYTRIDS. VI. RHOPALOPHLYCTIS AND CHYTRIOMYCES, TWO NEW CHITINOPHYLLIC OPERCULATE GENERA

Handbuch der biologischen Arbeitsmethoden

THE second part of the “Methoden der Susswasser-biologie” is a further instalment of that indispensable work “Handbuch der biologischen Arbeitsmethoden,” edited by Prof. Emil Abderhalden, and continues the description of freshwater biological methods begun in Part 115. The present portion begins with the rearing of freshwater insects of all groups, followed by other invertebrates. In such experimental work, the know ledge of the food required by the animals in question is essential, and a large amount of exact information is given as to the feeding at every stage. The culture of certain invertebrates as fish food has now become a matter of extreme importance, and special prominence is given to the small Crustacea such as the Cladocera, a separate chapter being given to Daphnia magna Straus. Then follow a long treatise on the rearing of freshwater fishes, more especially carp and trout, although others are also mentioned; a most interesting account of the methods of investigating the history of lake bottoms by means of samples taken by boring tubes and tube sounding leads; and finally chapters on boats for scientific work in inland lakes and a description of the working of the biological station at Lunz in the Austrian Alps. As each section is by an expert in his own line, we have an up-to-date account of all recent research methods which is of inestimable value to all freshwater biologists.

Observations and Experiments on Dragon-Flies in Brackish Water

Next article FreeObservations and Experiments on Dragon-Flies in Brackish WaterRaymond C. OsburnRaymond C. Osburn Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 40, Number 474Jun., 1906 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/278632 Views: 226Total views on this site Citations: 4Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:Kyle M. Knysh, Mark D. Saunders, Leah P. Macintyre, Simon C. Courtenay, Michael R. van den Heuvel Sometimes You Can Add a Bit of Salt: Additional Freshwater Insect Species in Canadian Estuaries, Northeastern Naturalist 29, no.11 (Mar 2022).https://doi.org/10.1656/045.029.0110Klaus W. Beyenbach The plasticity of extracellular fluid homeostasis in insects, The Journal of Experimental Biology 219, no.1717 (Aug 2016): 2596–2607.https://doi.org/10.1242/jeb.129650 William A. Dunson Adaptations of Nymphs of a Marine Dragonfly, Erythrodiplax berenice, to Wide Variations in Salinity, Physiological Zoology 53, no.44 (Sep 2015): 445–452.https://doi.org/10.1086/physzool.53.4.30157882E. M. Walker A PRELIMINARY LIST OF THE ODONATA OF SASKATCHEWAN, The Canadian Entomologist 72, no.22 (May 2012): 26–35.https://doi.org/10.4039/Ent7226-2