scholarly journals The Mechanisms of Humidity Reactions of Terrestrial Isopods

1941 ◽  
Vol 18 (2) ◽  
pp. 115-135
Author(s):  
NADEJDA WALOFF
Keyword(s):  
Water Loss ◽  
Whole Body ◽  
Negative Phototaxis ◽  
Moist Air ◽  
Porcellio Scaber ◽  
Positive Phototaxis ◽  
Terrestrial Isopods ◽  
Armadillidium Vulgare

1. The humidity reactions of Oniscus asellus, Porcellio scaber and Armadillidium vulgare have been analysed and compared. 2. The mechanism whereby the three species collect in moist air is twofold, consisting of (a) hygrokinesis, or decrease in activity and speed in moist air, and (b) of more frequent turnings in space, retaining them in the areas of greater humidity. 3. These mechanisms are most clearly expressed in Oniscus asellus and least in Armadillidium vulgare. This sequence may be correlated with the resistance to desiccation of the three species, which is greatest in Armadillidium vulgare, and greater in Porcellio scaber than in Oniscus asellus. 4. It is suggested that the humidity reactions of isopods are controlled by water loss by evaporation from the whole body. 5. A correlation between hygrokinesis and thigmokinesis was observed in Porcellio scaber. 6. There appears to be a reversal from negative to positive phototaxis in Oniscus asellus, correlated with the water loss by evaporation. 7. The humidity reactions, low thigmokinesis and negative phototaxis combine to retain the isopods in damp, dark habitats.

scholarly journals Occurrence of the Isopod Iridovirus in European Armadillidium and Porcellio (Crustacea, Isopoda)

1985 ◽  
Vol 55 (2) ◽  
pp. 280-282 ◽  
Author(s):  
George O. Poinar ◽  
Roberta T. Hess ◽  
Jan H. Stock
Keyword(s):  
The Netherlands ◽  
First Record ◽  
Blue Color ◽  
Porcellio Scaber ◽  
Terrestrial Isopods ◽  
Armadillidium Vulgare ◽  
Bright Blue

First record of iridovirus infections of terrestrial isopods (Armadillidium vulgare and Porcellio scaber) in Europe (The Netherlands). Infested specimens can be detected by their bright blue color.

Terrestrial life in isopods: evolutionary loss of gas-exchange and survival capability in water

1993 ◽  
Vol 71 (7) ◽  
pp. 1372-1378 ◽  
Author(s):  
Barbara E. Taylor ◽  
Thomas H. Carefoot
Keyword(s):  
Oxygen Consumption ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Fresh Water ◽  
Porcellio Scaber ◽  
Progressive Decline ◽  
Terrestrial Species ◽  
Terrestrial Isopods ◽  
Armadillidium Vulgare ◽  
Terrestrial Life

Survival and oxygen uptake in air and water were investigated in four species of terrestrial isopods, Armadillidium vulgare Latreille, 1804, Porcellio scaber Latreille, 1804, Oniscus asellus Linné, 1758, and Ligia pallasii Brandt, 1833, to compare the degree of vestigial adaptation to aquatic existence versus adaptation to terrestrial existence. Most submerged A. vulgare, P. scaber, and O. asellus died by 18 h, whether in fresh water or isosmotic seawater. Ligia pallasii lived for almost 2 d in fresh water and for at least 25 d in seawater (none died during this time). Oxygen uptake in water was 44 – 66% that in air for the three fully terrestrial species, and 160% that in air for the semiterrestrial L. pallasii. Oxygen consumption of submerged A. vulgare (representative of fully terrestrial forms) declined to 50% after 14 h and to 17% by 24 h, by which time the animals were clinically dead. In comparison, L. pallasii's aquatic oxygen consumption was maintained at normal or higher levels for at least 3 d. All species could survive several hours of immersion in fresh water, sufficient to withstand temporary rain deluge. Ligia pallasii's superior capabilities to survive and respire in seawater reflect its greater similarity to aquatic ancestors, and an evolutionary series showing progressive decline in survival and gas-exchange capability in water would be as follows: L. pallasii > O. asellus > P. scaber ≥ A. vulgare.

The Tachinid Parasites of Woodlice

Parasitology ◽  
1934 ◽  
Vol 26 (3) ◽  
pp. 378-448 ◽  
Author(s):  
W. R. Thompson
Keyword(s):  
Larval Morphology ◽  
Porcellio Scaber ◽  
Terrestrial Isopods ◽  
Armadillidium Vulgare

1. This paper comprises a study of the larval morphology and biology of the dipterous parasites of the terrestrial Isopods or woodlice.2. Porcellio scaber L., Oniscus asellus L., Metaponorthus pruinosus Brandt., and Armadillidium vulgare Lat., were found to be attacked by one or more of the parasites.3. Seven dipterous parasites have been reared and identified from woodlice: Plesina maculata Fall., Melanophora roralis L., Phyto melanocephala Meig., Styloneuria discrepans Pand., Frauenfeldia rubricosa Meig., Cyrillia angustifrons Rond., and Rhinophora lepida Meig. The biology and larval forms of all of these except R. lepida are described and figured, together with those of two undetermined species, “A” and “B.”

Natural and experimental associations of Caenorhabditis remanei with Trachelipus rathkii and other terrestrial isopods

Nematology ◽  
1999 ◽  
Vol 1 (5) ◽  
pp. 471-475 ◽  
Author(s):  
Scott Everet Baird
Keyword(s):  
Porcellio Scaber ◽  
Terrestrial Isopods ◽  
Terrestrial Isopod ◽  
Dauer Larvae ◽  
Caenorhabditis Remanei ◽  
Ventral Appendages

AbstractCaenorhabditis remanei was found in association with the terrestrial isopod Trachelipus rathkii at several wooded locations in southwestern Ohio. These associations were as developmentally arrested dauer larvae. The sites of association were the inner surfaces of the dorsal plates and ventral appendages. C. remanei associations also were observed with Armadillidium nasatum, Cylisticus convexus, and Porcellio scaber. They were not observed with Porcellio spinicornis even though P. spinicornis populations were intermingled with infested populations of T. rathkii. Consistent with the observed natural associations, C. remanei dauers were experimentally able to infest T. rathkii and P. scaber . Dauer larvae responded to confinement with isopods by nictating and by climbing upon these potential hosts. Experimental infestations were able to persist for at least five days. Long-term infestations were not attempted. Naturliche und experimentelle Vergesellschaftungen von Caenorhabditis remanei mit Trachelipus rathkii unde anderen terrestrischen Isopoden - An mehreren waldigen Stellen im Sudwesten von Ohio wurde Caenorhabditis remani vergesellschaftet mit dem terrestrischen Isopoden Trachelipus rathkii gefunden. Diese Assoziationen waren wie in der Entwicklung gehemmte Dauerlarven. Sie wurden an den inneren Oberflachen der Dorsalplatten und der ventralen Anhange festgestellt. Vergesellschaftungen von C. remani wurden auch mit Armadillium nasutum, Cylisticus convexus und Porcellio scaber beobachtet. Nicht beobachtet wurden sie dagegen bei Porcellio spinicornis, obwohl Populationen dieser Art mit infizierten Populationen von T. rathkii vermischt vorkamen. In Ubereinstimmung mit den beobachteten naturlichen Assoziationen konnten Dauerjuvenile von C. remani auch im Versuch T. rathkii und P. scaber befallen. Die Dauerjuvenile reagierten auf das enge Zusammensein mit den Isopoden durch Nickbewegungen und Klettern auf diese potentiellen Wirte. So ein experimenteller Befall konnte fur mindestens funf Tage bestehen. Langfristiger Befall wurde nicht versucht.

Changes in specific airway resistance during prolonged breathing of moist air

1970 ◽  
Vol 48 (9) ◽  
pp. 592-597 ◽  
Author(s):  
G. Norris Melville ◽  
W. T. Josenhans ◽  
W. T. Ulmer
Keyword(s):  
Relative Humidity ◽  
Water Content ◽  
Water Loss ◽  
Healthy Subjects ◽  
Airway Resistance ◽  
Tap Water ◽  
Distilled Water ◽  
Moist Air ◽  
Specific Airway Resistance ◽  
Water Elimination

Effects of increased water content of inspired air at 21–38 °C on specific airway resistance (sRaw) in 107 healthy subjects were measured with a body plethysmograph. Mean sRaw increased insignificantly at 23 °C with 92% relative humidity (water content, 20.7 g∙m−3) for up to 71 h but became significant at 6 h with water content 25 g∙m−3. Increases were greater when evaporated tap water was inhaled than when distilled water was used. It is postulated that the increase in sRaw is due to mucosal swelling and to contaminants in tap water. A theory of respiratory "water elimination" is proposed to replace the concept of respiratory water loss.

Evaporative water loss in domestic fowls and its partition in relation to ambient temperature

1976 ◽  
Vol 87 (3) ◽  
pp. 527-532 ◽  
Author(s):  
S. A. Richards
Keyword(s):  
Ambient Temperature ◽  
Water Loss ◽  
Absolute Humidity ◽  
Evaporative Water Loss ◽  
Linear Functions ◽  
Whole Body ◽  
Water Vapour Pressure ◽  
Evaporative Water ◽  
Open Flow ◽  
Low Levels

SummaryThe rate of evaporative water loss has been studied in domestic fowls in the ambient temperature range from 0 to 40°C.Results for whole-body evaporation were similar when obtained by the open-flow and direct-weighing methods. At low levels of absolute humidity the rate increased by 0·03 mg/(g.h.°C) from 0 to 22 °C and by 0·17 mg/(g.h.°C) from 23 to 40 °C. Wholebody evaporation decreased with rising ambient water vapour pressure by 0·7 mg/(g.h.kPa).Cutaneous water loss was greater than respiratory water loss below 21 °C; it accounted for 78% of whole-body evaporation at 0 °C, falling to 25% at 40 °C.The rates of respiratory and whole-body evaporation could both be expressed as linear functions of respiratory frequency.

Effect of chlorpromazine on phototactic behavior in Chlamydomonas

1980 ◽  
Vol 26 (2) ◽  
pp. 265-267 ◽  
Author(s):  
Rona Hirschberg ◽  
William Hutchinson
Keyword(s):  
Control System ◽  
Light Intensity ◽  
Antipsychotic Drug ◽  
Green Alga ◽  
Negative Phototaxis ◽  
Low Light ◽  
Positive Phototaxis ◽  
Phototactic Behavior ◽  
Common Control

Chlorpromazine, an antipsychotic drug, causes a light intensity dependent reversal of phototaxis in the green alga Chlamydomonas reinhardi. At moderate light intensity, drug-treated cells swim away from the light (negative phototaxis) while untreated cells swim toward it (positive phototaxis). At low light, both treated and untreated cells exhibit normal positive phototactic responses. It appears that light and chlorpromazine may affect a common control system for phototaxis.

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