Left: captive male Hyloxalus azureiventris
carrying tadpoles on its back in a terrarium.
Image by Dirk Ercken.
Below: a clutch of P. terribilis eggs in a
bromeliad. Image by Thorsten Spoerlein.
calls serve both to attract a female
and mediate spacing between males
in other territories. Any male that
trespasses will be viciously attacked.
Because courtship, mating and
oviposition occur in the leaf litter at
a single location, the possession of a
territory is a prerequisite to a male’s
reproductive success. In some cases,
however, a male will invade
another’s territory and there will be a
takeover. When this occurs the new
resident male will cannibalise the
clutch of the previous resident!
Manipulative studies have shown
that this behaviour is solely based on
territorial cues: if an unrelated clutch
is placed in a male’s territory he will
still perform parental duties, but if he
is removed to a new territory he will
cannibalise the clutch.
Although reliant upon a degree of
parental care, the terrestrial oviposi-
tion practiced by dendrobatids has
advantages; larvae are no longer at
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risk from aquatic predators, and
adults do not have to compete with
other frogs for oviposition sites. In
ephemeral ponds, in which many
frogs breed, conditions become
crowded, predation and cannibalism
is widespread, and the ponds
inevitably dry out!
Terrestrial oviposition may also have
resulted in dendrobatids deviating
from the typical mating behaviour of
most frogs, in which egg deposition
occurs during amplexus, where the
male grasps the female from behind