Full-text - Norsk entomologisk forening

from anoxia. Drops of haemolymph were
collected from a puncture in the neck, or by
cutting off one of the legs. Analysis of lactate
was carried out according to Strom (1949).
RESULTS AND DISCUSSION
The survival of beetles stored in nitrogen
at O0 C for various time intervals is shown
in Table 1. Although the material is limited,
it appears that al1 species have a high capacity
for survival under anaerobic conditions.
Most of the adults of P. borealis survided 156
days in nitrogen, which is a longer period
than previoiisly recorded (Conradi-Larsen &
Ssmme 1973b). Both Byrrhus fiilula L. (Byrrhidae)
and Otiorrhyncus dubius Strsm (Curculionidae)
survived 120 days of anoxia. Only
one specimen of Amara alpina (Carabidae)
and a few specimens of Lepyrus arcticus (Curculionidae)
were available, but the results
Table 1. Survival of
nitrogen at O0 C.
adult beetles stored in
No. of beetles
Days in Dead or
Species N2/0° Alive moribund
Pelophila borealis 117 3 1
156 14 4
Amara alpina 51 1 0
Byrrhi~s pilz~la 30 2 O
48 4 O
58 2 O
120 2 o
Lepyru~ arcticu~ 48 1 O
58 2 O
Otiorrhynchus dubitis 30 2 O
58 1 O
120 3 o
Table 11. Content of lactate in the haemolymph
of adult beetles stored in nitrogen at O0 C.
Species
Conc. of
Days in lactate (mM)
n Nn/OO x SE
Pelophila borealis 4 117 37.1 0.65
Amara alpina 1 5 1 13.3
Byrrhus pilula 4 4 8 20.2 +_ 1.44
Lepyrus arcticus 2 4 8 18.3
Otiorrhynchus dubius 1 51 46.7
indicate a high capacity to survive under
anoxia in these speGes as well.
During anoxia lactate was accumulated in
the haemol~mph of al1 species (Table 11). The
concentration varied from species to species,
but appeared to be exceptionally high in O.
dubius. Further investigations are necessary
to see if other end ~roducts of anaerobic
metabolism are formed.
It is concluded that al1 of the s~ecies
studied can survive extended periods of
anoxia. Anaerobic metabolism during anoxia
is demonstrated by the presence of lactate in
their haemolymph. Since oxygen deficiencies
are likely to occur in the natural habitats of
the beetles, anaerobic metabolism appears to
be an important part of winter survival in
al1 species.
As demonstrated by Pasche & Zachariassen
(1973), adults of the longicorn beetle Rhagium
inauisitor. which overwinters under the bark
of dead coniferous trees, can survive long
periods of low oxygen tension. In general it
may be expected that anaerobiosis in insects
is more common than previously recognized.
A large number of insect species oveiwinter
in moist habitats of various kinds, and may
experience periods of anoxia during the
winter. Further studies should be carried out
on overwintering and anaerobic metabolism
in species from different habitats.
ACKNOWLEDGEMENTS
1 am grateful to cand. real. A. Fjellberg for
identifying the specimens of Byrrhus pilula,
and to Mrs. 1. Tambs-Lyche for technical
assistance.
REFERENCES
Conradi-Larsen, E.-M. & Semme, L. 1973a. Anaerobiosis
in the overwintering beetle Pelophila
borealis. Nature 245, 388-390.
Conradi-Larsen, E.-M. & Semme. L. 1973b. The
overwintering of Pelophila borealis Payk. 11.
Aerobic and anaerobic metabolism. ,Vorsk cnt.
Tidsskr. 20, 325-332.
Lien, L., Ustbye, E., Hogstad, O.. Haande, K. M.,
Haande, P. S., Hagen A., Skar, H.-J., Skartveit,
A. & Svalastog, D. 19i.I. Bird surveys in the
high mountain habitats at Finse and Stigstuv,
Hardangervidda. South Norway, 1967-72.
Norw. J. Zooi. 22, 1-14.