QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online March 22, 2004
Journal of Experimental Biology 207, 1509-1521 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.00923

This Article Summary Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kostál, V. Articles by Bastl, J. Search for Related Content PubMed PubMed Citation Articles by Kostál, V. Articles by Bastl, J.

On the nature of pre-freeze mortality in insects: water balance, ion homeostasis and energy charge in the adults of Pyrrhocoris apterus

V. Kotál^1,*, J. Vambera² and J. Bastl³

¹ Institute of Entomology, Academy of Sciences, eské Budjovice, Czech Republic
² Faculty of Biological Sciences, University of South Bohemia, eské Budjovice, Czech Republic
³ Agricultural Faculty, University of South Bohemia, eské Budjovice, Czech Republic

View larger version (21K): [in a new window]   Fig. 1. Schematic depiction of the acclimation protocols used to obtain three different acclimation groups (LD, SD, SDA) of the adults of Pyrrhocoris apterus. See Materials and methods for a detailed description.

View larger version (16K): [in a new window]   Fig. 3. Relationships between the duration of the exposure to –5°C and the volume of haemolymph sample (A), the loss of fresh mass (FM) (inset) and the hydration of fat body cells (DM, dry mass) (B) in the adults of Pyrrhocoris apterus belonging to three different acclimation groups (LD, SD, SDA; see Fig. 1). In A, each data point represents a mean ± S.E.M. of 6 samples (LD) or 3 samples (SD, SDA), each consisting of pooled haemolymph taken from 10 insects. The probabilities that slopes of linear regressions deviate from zero were: LD, P<0.001; SD, P=0.469; SDA, P=0.136. In the inset, each data point represents a mean ± S.E.M. of 30 individuals weighed prior to and after the exposure to –5°C. In B, each data point represents a mean ± S.E.M. of 6 samples (LD) or 3 samples (SD, SDA), each consisting of pooled fat body tissues taken from 10 insects. The probabilities that slopes of linear regressions deviate from zero were: LD, P=0.567; SD, P=0.204; SDA, P<0.001.

View larger version (15K): [in a new window]   Fig. 2. Relationships between the duration of the exposure to –5°C and (A) the pre-freeze mortality or (B) the recovery time after chill-coma in the adults of Pyrrhocoris apterus belonging to three different acclimation groups (LD, SD, SDA; see Fig. 1). In A, each data point represents a mortality rate in the group of 10–30 individuals [Boltzmann sigmoidal curves were used to fit the data: LD, R2=0.7103 (goodness of fit); SD, R2=0.7900]. The arrows show times necessary to kill 50% of the population sample (Lt50). In B, each data point represents a mean ± S.E.M. of 10 individuals. The probabilities that slopes of linear regressions deviate from zero were P<0.001 for all groups.

View larger version (28K): [in a new window]   Fig. 4. Relationships between the duration of the exposure to –5°C and the concentrations of sodium (A,B) or potassium ions (C,D) in either haemolymph (A,C) or fat body cells (B,D) in the adults of Pyrrhocoris apterus belonging to three different acclimation groups (LD, SD, SDA; see Fig. 1). Each data point represents a mean ± S.E.M. of 6 samples (LD) or 3 samples (SD, SDA), each consisting of pooled tissues taken from 10 insects. The probabilities that slopes of linear regressions deviate from zero were: (A) LD, P=0.016; SD, P=0.724; SDA, P=0.274; (B) LD, P=0.527; SD, P=0.602; SDA, P=0.917; (C) LD, P<0.001; SD, P=0.003; SDA, P<0.002; (D) LD, P=0.142; SD, P=0.009; SDA, P=0.017.

View larger version (21K): [in a new window]   Fig. 5. Relationship between the duration of the exposure to –15°C and the concentrations of sodium and potassium ions in haemolymph in the adults of Pyrrhocoris apterus belonging to the acclimation group SDA (see Fig. 1). Each data point represents mean ± S.E.M. of 10 samples of haemolymph taken from individual insects. The probabilities that slopes of linear regressions deviate from zero were: K+, P<0.001; Na+, P=0.013. The solid arrow shows time necessary to kill 50% individuals of the population sample (Lt50). For comparison, the Lt50 (broken arrow) and linear regressions (broken lines) of the haemolymph concentrations of the two ions in the acclimation group LD exposed to –5°C are shown (redrawn from Fig. 4A,C).

View larger version (28K): [in a new window]   Fig. 6. Relationships between the duration of the exposure to –5°C and the equilibrium potentials of sodium (upper part) and potassium ions (lower part) across the fat body membrane in the adults of Pyrrhocoris apterus belonging to three different acclimation groups (LD, SD, SDA; see Fig. 1). Each data point represents a mean ± S.E.M. of 6 (LD) or 3 (SD, SDA) equilibrium potentials calculated using the data shown in Fig. 4. The probabilities that slopes of linear regressions deviate from zero were: Na+: LD, P=0.756; SD, P=0.684; SDA, P=0.584; K+: LD, P<0.001; SD, P=0.001; SDA, P=0.117.