Abstract:
Laboratory experiments and simulated field conditions were
utilized to gain a better understanding of the ecology of the clouded
salamander.
Animals collected in western Oregon were utilized for studies
in habitat selection, where it was shown that there was a significant
pattern of selection of litter types (rock, bark, and leaves) by size
classes and at different temperatures. The young displayed a
preference for bark litter, the immature displayed an intermediate
preference between rock litter and bark Utter, and the adults
showed little or no preference between bark litter and rock litter.
Respiratory rates were measured by a Gilson differential
respirometer. The effects of size, temperature (10, 20, 25°C), and
feeding regime were noted. Young animals displayed the highest
rates of respiration, with fed individuals significantly higher than
nonfed. Immature animals exhibited a respiratory rate intermediate between the young and adults. Those fed had higher respiratory rates
at higher temperatures than did the nonfed. Adults showed the lowest
respiratory rates and displayed no significant variation between fed
and nonfed individuals.
Population characteristics were described by detailed analysis
of the dorsal and ventral color patterns. Individuals were categorized
into color classes (adult, immature, and young). Adults tended to
have a dark dorsal surface and a relatively light colored venter.
Immature animals were more extensively colored on the dorsum with
a relatively dark venter. The young displayed the most concentrated
colors on the dorsum and had the darkest venter. The live young
always possessed blue leucophores.
Reproductive studies revealed the possibility of determining sex,
in all sizes of animals, by analysis of the inner vent. Through dissections
of animals from all months except January, mature males
were shown to have little annual variation in appearance and size of
testes and vasa deferentia. Sperm were found in mature male vasa
deferentia in every month except September. Males are believed to
mature during the second year or at a snout-vent length of over 36
mm. Females contained sperm in their spermathecae in every month
that late egg development was evident. Mature females probably lay
eggs every other year after attaining a size of about 55 mm (snoutvent
length). The first egg laying is probably in the third year of life. A prolonged breeding period is likely with spermatophore
deposition in early May. About 12 eggs are deposited in late June
and throughout July with hatching approximately two months later.
The newly hatched individuals measured 25. 9 mm (total length)
and fed in 14 days.
There was a differential death pattern, inversely proportional to
size.
