Étude De l'ACCLIMATION Thermique Chez La Limace Arion Circumscriptus

Abstract

Slugs of the speriee A r i m cirnmrrrifihs were acclimated to temperatures of jn, gC, 109 20", and 25" C respectively. After acclinlation, nietabolic rate was determined, either as oxygen consumption, ac 30" and 20", or by direct dor rimetry, at 25' and 12.5". At all qiven expostkre temperatures, the average rnetaholic rate ttas lower, I y I % to 1.5?&, fur each d e~r e e of increase in the acclimation temperature. Khen the Iogarith~ns of total 0~ conslimption or heat production per hour are plottcd against the Iwarithnls of body weight. the rqression Iine obtained for slups acclimatd to heat stands lielow that ohwined for slugs acclimated to cold; the s t o p is alw slighter for the warm-admated slugs t h a n fnr the cold-acchated, so that the distance I~t w e e n correspondi~lg points of two such curves is larger in the ri~hthand side of the graph, where the, large specimens are represented, than in thc lefthand side where the sma1l specmens are shown. This would imply that a n increase i n the acclimation temperature reduces metabofir-rate to a proportionately greater extent in the larger specimens than i t does in the smaller nncs. The value of the slope, which is inversely correlated with acclimation cempemture, is also inverselv correlated with the esprinwntal temperature a t which metabolism is determind. (A) Introduction ( a ) L'ACCLIMATATION CHEZ LES POIKILOTHERMES AQUATIQUESLes ittudes ritalisites B date sur l'acclimatation thermique des poikilothermes ont portit surtout sur des organismes marins ou aquatiques. Deux effets gCnCraux ont CtC observks A la suite de sejours prolonges A des temperatures differentes: les animaux a d a p t b ou acclimatCs au froid ont un taux de mCtabolisnle plus Clev6 que les animaux adapt& ou acclimates A la chaleur, si les determinations de metabolisme sont effectuees A une m&me temperature; de plus les temperatures littales, superieure e t inferieure, sont plus basses chez les animaux adapt& ou acclimates au froid que chez les animaux adapt& ou acclimatits A la chaleur.Ces deux effets ont kt6 verifiits A trois niveaux differents. On a comparit des populations vivant dans des habitats de tempCratures moyennes differentes; les differences observkes alors dans le taux de metabolisme e t dans les temperatures letales sont dksignites, suivant la terminologie de Hart (1957)' comme une "adaptation". Les differences de rnCtabolisme ou de tempitratures letales observees d'une saison A l'autre A l'intkrieur d'une meme population constituent ce que Hart appelle "acclimatisation". Enfin, les r b u l t a t s obtenus en laboratoire, sur des groupes d'animaux provenant d'une m&me population e t qu'on a fait sitjourner B des temperatures differentes, en contrdlant les autres facteurs d u milieu, constituent, suivant la meme terminologie, une "acclimation". Nous conserverons au terme "acclimatation thermique" le sens general d'ajustement physiologique en rCponse A un sejour prolong6 A une temperature donnee: ainsi 1"'acclimation" pourrait se definir comme une acclimatation

Variations in the relationship between oxygen consumption, body size and summated tissue metabolism in the winkleLittorina littorea

“…This conclusion supports the data of Edwards & Irving (1943 b) and Edwards (1946) replotted by Rao & Bullock (1954) for Talorchestia in which the value for b-i at comparable temperatures was greater in animals collected during the winter than during the summer. On the other hand Roy (1963; has shown that in the slug Arion circumscriptus the value of the slope b was inversely correlated with both experimental temperature and acclimation temperature, which is the reverse of the relationship found in Littorina and Talorchestia. Again in excised specimens of Balanus balanoides, B. balanus and Chthamalus stellatus the values for the slope b -1 tend to be greater in the summer or at high temperatures than in the winter or at low experimental temperatures (Barnes & Barnes, 1969).…”

“…This implies that the presence of the cell surface controls the size dependence of metabolism in the winkle L. littorea. This simple interpretation is, however complicated by the seasonal variation in the value of the slope b-x which has been demonstrated in several invertebrates including L. littorea, Talorchestia (Edwards & Irving, 19436;Edwards, 1946;Rao & Bullock, 1954), Balanus and Chthamalus (Barnes & Barnes, 1969), and which is controlled by acclimation temperature in the slug Arion circumscriptus (Roy, 1963(Roy, , 1969. Such changes in the relationship between the weightspecific metabolic rate and body size must reflect some more complex phenomenon whose influence may be superimposed upon the effects of aggregate cell surface area, but there is little evidence at present to suggest the means by which the weight regression could be modified.…”

“…On the other hand in specimens of Talorchestia collected during the winter the values of b -1 were high at each end of the range of experimental temperatures from 7-32 °C but lower at 12-17 °C. A very detailed study of the combined effects of experimental temperature and acclimation temperature on the relation between body size and metabolism has been recently made on the slug Arion circumscriptus by Roy (1963Roy ( ,1969. He found that the value b, instead of being a constant, showed a definite pattern of variation between a value of 0-55 and 0-93 according to experimental temperature and acclimation temperature.…”

Interactive effects of intrinsic and extrinsic factors on metabolic rate

“…[20,24,34,40,92,93]) food habits (e.g. [2,4,72,[175][176][177]) habitat/microhabitat (e.g. [4,20,24,156,[178][179][180][181][182]) captivity (e.g.…”

Tolerance to extreme hot and cold temperatures in the EU-protected terrestrial slugGeomalacus maculosus

“…Prior to experiments (conducted in April and May 2016), they were kept for at least one week in water baths set at a constant temperature of 15°C to facilitate acclimatisation. This was done following Roy (1963) who suggested that five days are sufficient to complete the metabolic thermal acclimatisation in Arion circumscriptus slugs exposed to different temperatures. For the experiment, a mixture of both phenotypes (black-brown and yellow-brown) of 120 adults which were about equal in size was used.…”