The Influence of the Hydrogen-Ion Concentration in the Development of Mosquito Larvae. Preliminary Contribution

MacGregor, Malcolm E.

doi:10.1017/s0031182000012567

Cited by 25 publications

(12 citation statements)

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“…Prior reports have documented the remarkable abilities of larval mosquitoes to tolerate waters characterized by differences in H + concentrations of many orders of magnitude (Keilin, 1932;Kurihara, 1959;MacGregor, 1921;Peterson and Chapman, 1970). We extend those findings by demonstrating similar, broad pH tolerances in species with very different salinity tolerances.…”

Section: Discussionmentioning

confidence: 99%

“…There is no evidence that pH ever limits the habitats of larval mosquitoes in nature (Clements, 2000), where reported pH values for larval habitats range from 3.3 to 8.1 (Ochlerotatus taeniorhynchus), 4.4-9.3 (Aedes geniculatus), 3.3-9.2 (Psorophora confinnis), and 4.4-9.3 (Anopheles plumbeus). In the laboratory, Aedes flavopictus has been reared in waters ranging from pH 2-9, and Armigeres subalbatus in the pH range of 2-10 ( Keilin, 1932;Kurihara, 1959;MacGregor, 1921;Peterson and Chapman, 1970).…”

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confidence: 99%

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pH tolerances and regulatory abilities of freshwater and euryhaline Aedine mosquito larvae

Clark

Flis

Remold

2004

Journal of Experimental Biology

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The pH regulatory abilities of two members of the mosquito tribe Aedini, known to have dramatically different saline tolerances, are investigated. The freshwater mosquito Aedes aegypti and the euryhaline Ochlerotatus taeniorhynchus tolerate very similar pH ranges. Both species complete larval development in waters ranging from pH·4 to pH·11, but naïve larvae always die in water of pH·3 or 12. Across the pH range 4-11, the hemolymph pH of O. taeniorhynchus is maintained constant while that of A. aegypti varies by 0.1 pH units. The salt composition of the water (3.5·g·l -1 sea salt, 3.5·g·l -1 NaCl, or nominally salt-free) has no effect on the range of pH tolerated by A. aegypti. In both species, the effects of pH on larval growth and development are minor in comparison with the influence of species and sex. Acclimation of A. aegypti to pH·4 or 11 increases survival times in pH·3 or 12, respectively, and allows a small percentage of larvae to pupate successfully at these extreme pH values. Such acclimation does not compromise survival at the other pH extreme.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

pH tolerances and regulatory abilities of freshwater and euryhaline Aedine mosquito larvae

Clark

Flis

Remold

2004

Journal of Experimental Biology

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“…albopictus larvae at high acidity and alkalinity. Other tree hole mosquito species such as Anopheles plumbeus (Stephens) and Aedes geniculatus (Olivier) may have advantages at lower pH, as they can survive in water with pH 4.4 (MacGregor 1921, Keilin 1932.…”

Section: Resultsmentioning

confidence: 99%

Effects of Larval Habitat Substrate on Pyriproxyfen Efficacy Against <I>Aedes albopictus</I> (Diptera: Culicidae)

Suman¹,

Wang²,

Dong³

et al. 2013

jnl. med. entom.

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Most pesticide formulations such as dry flowables, emulsifiable concentrates and wettable powders are designed to be diluted with water as the carrier. A water pH higher than 7 which creates alkaline conditions can cause some pesticides to undergo degradation or chemical breakdown, a process known as hydrolysis. In general, insecticides are much more susceptible to hydrolysis than are fungicides, herbicides, defoliants or growth regulators. Organophosphate and carbamate insecticides are more susceptible than chlorinated hydrocarbon insecticides. Some pyrethroids exhibit susceptibility to hydrolysis.Tables reporting the pH of water sources across the U.S. list only a few states that have water with a pH below 7 which is in the acid range. The rest all have sources with varying degrees of alkalinity. Both surface and ground water supplies usually contain sufficient natural alkalinity to produce pH levels between 7 and 9.Some pesticides hydrolyze very rapidly. The hydrolysis rate can be rapid in the pH range of 8 to 9. For every pH point increase, the rate of hydrolysis will increase by approximately 10 times. The severity of losses due to alkaline hydrolysis is governed by the degree of water alkalinity, the susceptibility of the pesticide, the amount of time the pesticide is in contact with the water and the temperature of the mixture.The solution to the problem is lowering the pH of the water to the optimum range of 4 to 7 before mixing with the pesticide. This is accomplished by adding the recommended amount of buffering or acidifying agent. It should be noted that the buffering does not affect the residual activity of the pesticide. The buffering effect starts at the time of mixing, continues during storage in the tank, and does not stop until the water has evaporated from the spray droplet. Some materials, such as fixed copper fungicides including basic copper sulfate, copper oxide, and Bordeaux mixtures, should not be buffered as the acid solution may make the metals soluble and produce a phytotoxic effect when sprayed on plants. Products used to acidify tank solutions may be straight acidifying agents or in combination with surfactants or nutrient materials like trace elements or fertilizer products.A pH meter is the most accurate method of determining the pH of water. The use of test papers, such as litmus paper can be non-reliable and can be as much as two pH points in error. There air liquid color indicators (example: Bromothymol Blue) available which can indicate pH to within a half point. Water sources, both surface and ground, can and do change in pH with the passage of time. The change in pH is usually towards a more alkaline condition.

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“…Saprolegnia infects a wide variety of organisms, including insects, turtles, fishes, and amphibians (MacGregor 1921, Seymour 1970. In amphibians, embryos and larvae can become infected (Bragg & Bragg 1958, Walls & Jaeger 1987, Blaustein et al 1994.…”

Section: Introductionmentioning

confidence: 99%

“…Host species show strong interspecific variation in their susceptibility to infection (Richards & Pickering 1978, Wood & Willoughby 1986, Kiesecker & Blaustein 1995. Factors such as water temperature, pH, pollution, exposure to UV-B radiation, injury from biting, silt, and host behavior may modify the effects of Saprolegnia on its hosts (MacGregor 1921, Strijbosch 1979, Walls & Jaeger 1987, Banks & Beebee 1988, Carballo & Muñoz 1991, Bly et al 1993, Pickering 1994, Carballo et al 1995, Kiesecker & Blaustein 1995, Lefcort et al 1997. Saprolegnia may influence community structure by altering competition between hosts (Kiesecker & Blaustein 1999).…”

Section: Introductionmentioning

confidence: 99%

Effects of nitrate and the pathogenic water mold Saprolegnia on survival of amphibian larvae

Romansic¹,

Diez²,

Higashi³

et al. 2006

Dis. Aquat. Org.

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We tested for a synergism between nitrate and Saprolegnia, a pathogenic water mold, using larvae of 3 amphibian species: Ambystoma gracile (northwestern salamander), Hyla regilla (Pacific treefrog) and Rana aurora (red-legged frog). Each species was tested separately, using a 3 × 2 fully factorial experiment with 3 nitrate treatments (none, low and high) and 2 Saprolegnia treatments (Saprolegnia and control). Survival of H. regilla was not affected significantly by either experimental factor. In contrast, survival of R. aurora was affected by a less-than-additive interaction between Saprolegnia and nitrate. Survival of R. aurora was significantly lower in the Saprolegnia compared to the control treatment when nitrate was not added, but there was no significant difference in survival between Saprolegnia and control treatments in the low and high nitrate treatments, consistent with increased nitrate preventing Saprolegnia from causing mortality of R. aurora. Survival of A. gracile followed a similar pattern, but the difference between Saprolegnia and control treatments when nitrate was not added was not significant, nor was the nitrate × Saprolegnia interaction. Our study suggests that Saprolegnia can cause mortality in amphibian larvae, that there are interspecific differences in susceptibility and that the effects of Saprolegnia on amphibians are context-dependent. KEY WORDS: Pathogen · Saprolegnia · Amphibian Resale or republication not permitted without written consent of the publisherDis Aquat Org 68: [235][236][237][238][239][240][241][242][243] 2006 Saprolegnia, a water mold, is one important pathogen found in many amphibian populations (e.g. Strijbosch 1979, Banks & Beebee 1988, Blaustein et al. 1994. Furthermore, Saprolegnia-associated mortality appears to increase in the presence of abiotic stressors (Strijbosch 1979, Banks & Beebee 1988, Kiesecker & Blaustein 1995, Kiesecker et al. 2001a.Saprolegnia (family Saprolegniaceae) is both saprobic and parasitic, obtaining nutrition from decaying organic matter or living hosts (Seymour 1970). Saprolegnia infects a wide variety of organisms, including insects, turtles, fishes, and amphibians (MacGregor 1921, Seymour 1970. In amphibians, embryos and larvae can become infected (Bragg & Bragg 1958, Walls & Jaeger 1987, Blaustein et al. 1994. Saprolegnia-infected embryos of fishes and amphibians become covered with visible white hyphal filaments and usually do not hatch (Blaustein et al. 1994). Infection can spread via contact from growing hyphae (in the case of immobile hosts such as amphibian egg masses) or through colonization by free-swimming zoospores (Wood & Willoughby 1986). Transmission can occur between species, for example, between fishes and amphibians (Kiesecker et al. 2001b). Fishes and amphibians may also be infected by Saprolegnia via contact with infected soil (Kiesecker et al. 2001b). Host species show strong interspecific variation in their susceptibility to infection (Richards & Pickering 1978, Wood & Willoughby 1986, Kiesecker & Blau...

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The Influence of the Hydrogen-Ion Concentration in the Development of Mosquito Larvae. Preliminary Contribution

Cited by 25 publications

References 0 publications

pH tolerances and regulatory abilities of freshwater and euryhaline Aedine mosquito larvae

pH tolerances and regulatory abilities of freshwater and euryhaline Aedine mosquito larvae

Effects of Larval Habitat Substrate on Pyriproxyfen Efficacy Against <I>Aedes albopictus</I> (Diptera: Culicidae)

Effects of nitrate and the pathogenic water mold Saprolegnia on survival of amphibian larvae

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