EcaLouY, SYSTEMATICS AND EVOLUTION
OF AUSTRALUN
46
c. BREEDING BIOLOGY
1. Oviposition
The breeding habits of Australian frogs have been discussed by
Fletcher (1889), and Main et al. (1959). Figure 4 summarises present
knowledge of southern Western Australian epecies. It is basically that
of Main et al. ( o p cit.) with data on female biology included for specie8 of
Crinia, Pseud0phyn.e and Neobatmhu.8. Data pertaining to females of
H e k i o p m s species are not included because it ie believed that in this
genus breeding is strictly seasonal regardless of the weather and temperature conditions (Lee, 1967). Females enter the breeding sites in late
Autumn to lay unpigmented eggs in a frothy mws in a burrow,
specially excavated by the male, at a site which will later be flooded
by winter rains. The breeding appears to be unrelated to rainfall or temperature conditions. In fact, when rain floods the low-lying breeding
sites no further egg laying occurs. This usually happens about the end
of May.
From Fig. 4 it is apparent that in some species, e.g. Neobatrachw
centralis and Pseud0phryne midentalis, females may be present over
the whole season and temperature range that males have been heard
calling On the other hand females of C . pseudimignifera are not present
over the whole season or temperature range that males have been heard
calling. Purthermore in those cases where sufficient gravid females have
been collected it has been possible to calculate the mean temperature
a t which females breed (mean breeding temperature). Thew means
have been indicated in Fig. 4. The means of species which breed following summer rains are above 16°C while those breeding in winter are
below this temperature. Crinia pseudinsignifera is noteworthy because
of its low mean breeding temperature. The difference between the mean
breeding temperature of C. p,seudimignifera (49 observations) and
Cr. insignifera (181 observations) is highly significant (p < 0.001). The
breeding biology of frogs of southern Western Australia is suIllII18Fi88a
in Table 11.
The relationship between size of frog, egg size and site of oviposition
is shown in Fig. 6. The egg of Crinia georgiana ie the largest laid in water
(though it is usually never deeper than 10 mm); with this exception no
egg larger than 1.7 mm yolk diameter is known to be laid in water. On
the other hand, again with the exception of C. georgiana, no egg smaller
than 1-95 mm is known to be laid out of water. The eggs of My&trachus gouldii, Metaerinia nichollsi, and Taudactylus diurnw have not
been found in nature. However, the size of the eggs of these species is
consistent with the belief that embryonic development at least takes
place cut of water.
OF AUSTRALUN
46
c. BREEDING BIOLOGY
1. Oviposition
The breeding habits of Australian frogs have been discussed by
Fletcher (1889), and Main et al. (1959). Figure 4 summarises present
knowledge of southern Western Australian epecies. It is basically that
of Main et al. ( o p cit.) with data on female biology included for specie8 of
Crinia, Pseud0phyn.e and Neobatmhu.8. Data pertaining to females of
H e k i o p m s species are not included because it ie believed that in this
genus breeding is strictly seasonal regardless of the weather and temperature conditions (Lee, 1967). Females enter the breeding sites in late
Autumn to lay unpigmented eggs in a frothy mws in a burrow,
specially excavated by the male, at a site which will later be flooded
by winter rains. The breeding appears to be unrelated to rainfall or temperature conditions. In fact, when rain floods the low-lying breeding
sites no further egg laying occurs. This usually happens about the end
of May.
From Fig. 4 it is apparent that in some species, e.g. Neobatrachw
centralis and Pseud0phryne midentalis, females may be present over
the whole season and temperature range that males have been heard
calling On the other hand females of C . pseudimignifera are not present
over the whole season or temperature range that males have been heard
calling. Purthermore in those cases where sufficient gravid females have
been collected it has been possible to calculate the mean temperature
a t which females breed (mean breeding temperature). Thew means
have been indicated in Fig. 4. The means of species which breed following summer rains are above 16°C while those breeding in winter are
below this temperature. Crinia pseudinsignifera is noteworthy because
of its low mean breeding temperature. The difference between the mean
breeding temperature of C. p,seudimignifera (49 observations) and
Cr. insignifera (181 observations) is highly significant (p < 0.001). The
breeding biology of frogs of southern Western Australia is suIllII18Fi88a
in Table 11.
The relationship between size of frog, egg size and site of oviposition
is shown in Fig. 6. The egg of Crinia georgiana ie the largest laid in water
(though it is usually never deeper than 10 mm); with this exception no
egg larger than 1.7 mm yolk diameter is known to be laid in water. On
the other hand, again with the exception of C. georgiana, no egg smaller
than 1-95 mm is known to be laid out of water. The eggs of My&trachus gouldii, Metaerinia nichollsi, and Taudactylus diurnw have not
been found in nature. However, the size of the eggs of these species is
consistent with the belief that embryonic development at least takes
place cut of water.