20
Water Balance in Mediterranean Arthropods
~ mM/ICIH
A
800
" 600
E
'"
0
E 400
200
HI
IV
IX
IV
V
VI VII IX
Fig. 2.2. The relationship of haemolymph osmolality to concentration of CI- in the isopods
Hemilepistus reaumuri(H) and Armadillo officinalis (A) during different months (III-IX). (Warburg 1987a)
Haemolymph
350 osmotic pressure
I mosmo/ /I ter -I}
f
Orcheselia li V \
clncta f---+~~ \
,
-~
IB}
340
320
, 17}
\
f /romocerus
~
300
¥' minor
IS}
/ '
IS} 16i\3}
IS}
Is}~
!(S)
2BO
250 --+ ~:---'--2::--'---:3:---'--4-:-""""'-s-;:-- + days
Fig. 2.3. Haemolymph osmolality in an instar of the collembolan Orchesella cincta and the collembolan Tomocerus minor. Numbers in parentheses are the numbers of test specimens ... Ecdysis. (Verhoef 1981)
In this state, mortality is negligible and animals can survive for long periods.
With restored environmental moisture, the animals' activity recovers rapidly.
Other collembolan species, including Tomocerus minor, are not capable of
osmoregulation. With desiccating substrates - resulting in decreasing food