Adaptation to Moisture Variations
23
100
11
14
10
7 98%RH
10
L:
4
.Ql 95
~
~
~
4
' 15 90
Q)
01
.!2 c Q) 85
~
< 10%R
&.
o 1 0 20 30 40 50 60 70 80
Time (h)
Fig. 2.5. Percentage of water loss in female Archispirostreptus syriacus at three different relative
air humidities (RH). Numbers indicate the numbers of test specimens. (Crawford et al. 1986)
sonally varying patterns in the permeability of the cuticle of the diplopod
Ommatoiulus moreletii. More specifically, he suggested that the new spring
and summer cuticles formed after moulting (which occurs in spring) were
probably less permeable than the autumnal ones. Furthermore, he linked the
impairment of the cuticle, which resulted in increased permeability, to activity and concluded that low summer activity may have resulted in lower
cuticle abrasion, while high autumnal activity may have caused it to increase.
The overall conclusion is that, irrespective of age and sex, the animals are
more resistant under the stress of summer (Ghabbour and Rizk 1979). In
addition, Baker (1980) reported seasonal changes in the water content of the
animals: the highest values were recorded in spring and summer.
Seasonal variations in body water content differ in species from mesic and
desert environments. In the diplopod A. t. judaicus, for instance, a higher proportion of body water was recorded in the gut and haemolymph than in the
tissues and cuticle during the cool wet period. The reverse was found in the
strictly xeric desert diplopod Orthoporus ornatus. Intraspecific differences in
terms of activity of A. t. judaicus from mesic and xeric regions were attributed to differences in habitat (Crawford et al. 1987). In summer, significantly lower body water and haemolymph osmolality were recorded in animals
from xeric habitats. These differences were consistent with the properties of
the habitats. Desert animals experiencing considerable microclimatic gradients when moving through relatively cool subterranean and hot open surface
sites were able to regulate the distribution of water between the gut and gut
contents on the one hand and the haemolymph, cuticle and tissues on the
23
100
11
14
10
7 98%RH
10
L:
4
.Ql 95
~
~
~
4
' 15 90
Q)
01
.!2 c Q) 85
~
< 10%R
&.
o 1 0 20 30 40 50 60 70 80
Time (h)
Fig. 2.5. Percentage of water loss in female Archispirostreptus syriacus at three different relative
air humidities (RH). Numbers indicate the numbers of test specimens. (Crawford et al. 1986)
sonally varying patterns in the permeability of the cuticle of the diplopod
Ommatoiulus moreletii. More specifically, he suggested that the new spring
and summer cuticles formed after moulting (which occurs in spring) were
probably less permeable than the autumnal ones. Furthermore, he linked the
impairment of the cuticle, which resulted in increased permeability, to activity and concluded that low summer activity may have resulted in lower
cuticle abrasion, while high autumnal activity may have caused it to increase.
The overall conclusion is that, irrespective of age and sex, the animals are
more resistant under the stress of summer (Ghabbour and Rizk 1979). In
addition, Baker (1980) reported seasonal changes in the water content of the
animals: the highest values were recorded in spring and summer.
Seasonal variations in body water content differ in species from mesic and
desert environments. In the diplopod A. t. judaicus, for instance, a higher proportion of body water was recorded in the gut and haemolymph than in the
tissues and cuticle during the cool wet period. The reverse was found in the
strictly xeric desert diplopod Orthoporus ornatus. Intraspecific differences in
terms of activity of A. t. judaicus from mesic and xeric regions were attributed to differences in habitat (Crawford et al. 1987). In summer, significantly lower body water and haemolymph osmolality were recorded in animals
from xeric habitats. These differences were consistent with the properties of
the habitats. Desert animals experiencing considerable microclimatic gradients when moving through relatively cool subterranean and hot open surface
sites were able to regulate the distribution of water between the gut and gut
contents on the one hand and the haemolymph, cuticle and tissues on the