FAUNA AND FLORA OF MANGROVE SWAMPS
193
A second question to which one would like an answer is : does a male
keep territory for more than one intertidal period? If so, for how many?
On the coasts of eastern Africa the mud-skippers construct burrows
of two distinct types. I n the large mangals between Quissanga and
Ibo (lat. 12’s.) both are present. One type of burrow is wide mouthed
and single, the rim raised about 2.5 or 3 cm above the general level of
the soil. This burrow I presume to be constructed by P. sobrinus. The
other type, which I presume to be made by P. kalolo, possesses twin
turrets, each one some 5-7 cm high. When examined the burrow is
Y-shaped.
Petit (1922) described burrow construction by P. koelreuteri
(= P. kalolo). He mentions the twin turrets and describes their
construction as follows :
Lorsqu’il eut amorc6 ainsi son terrier, le PBriophtalme se mit B le creuser
avec sa bouche, enlevant la terre, parcelle par parcelle comme nous l’avons
vu tout B l’heure lorsqu’il recherchait sa nourriture, mais se retournant pour
dkposer chaeune de ces parcelles & 2 ou 3 centimetres de l’orifice. Ainsi fut
commencke la premiere assise du rempart, du c8tk interne de laquelle et sur
laquelle se seraient dBpos6es d’autres parcelles et d’autres assises.
Stebbins and Kalk (1961) describe the turrets which are made of pellets
of mud and mention the sight of individuals coming to the mouth of
the burrow, there to squirt out, like tooth-paste from a tube, the mass
of mud being carried within the mouth.
At low tide this burrow appears to be used as the centre of the
defended area. The male perches within the entrance and has been seen
to emerge to make a sally a t another which approaches too closely. In
making such a sally he raises and lowers his dorsal fins, flash-displaying
the black, white and orange stripes which are such a marked feature of
them (Petit, 1922, and personal observation). I n most cases the
wanderer retreats without “showing the flag”, but he may, presumably if he is in a state of sexual readiness, challenge, and he may
even drive away the owner of the burrow. While the male perches at
the mouth of one turret the female crouches behind him. How pairing
becomes established is not known. An interesting distraction display
may be seen. On approaching an occupied pair of turrets one individual
may be seen to leave and skitter away, a female will be found resting
quietly within the burrow (cf. drooping wing act of birds).
The eggs are deposited by the female, with the male in attendance,
on the walls of the burrow (de Freitas, unpublished observations). The
story of the completion of hatching and early development has not
been worked out in the field. Kimura (1958) has followed the sequence
in the laboratory and has shown that a typical gobioid larva emerges.
193
A second question to which one would like an answer is : does a male
keep territory for more than one intertidal period? If so, for how many?
On the coasts of eastern Africa the mud-skippers construct burrows
of two distinct types. I n the large mangals between Quissanga and
Ibo (lat. 12’s.) both are present. One type of burrow is wide mouthed
and single, the rim raised about 2.5 or 3 cm above the general level of
the soil. This burrow I presume to be constructed by P. sobrinus. The
other type, which I presume to be made by P. kalolo, possesses twin
turrets, each one some 5-7 cm high. When examined the burrow is
Y-shaped.
Petit (1922) described burrow construction by P. koelreuteri
(= P. kalolo). He mentions the twin turrets and describes their
construction as follows :
Lorsqu’il eut amorc6 ainsi son terrier, le PBriophtalme se mit B le creuser
avec sa bouche, enlevant la terre, parcelle par parcelle comme nous l’avons
vu tout B l’heure lorsqu’il recherchait sa nourriture, mais se retournant pour
dkposer chaeune de ces parcelles & 2 ou 3 centimetres de l’orifice. Ainsi fut
commencke la premiere assise du rempart, du c8tk interne de laquelle et sur
laquelle se seraient dBpos6es d’autres parcelles et d’autres assises.
Stebbins and Kalk (1961) describe the turrets which are made of pellets
of mud and mention the sight of individuals coming to the mouth of
the burrow, there to squirt out, like tooth-paste from a tube, the mass
of mud being carried within the mouth.
At low tide this burrow appears to be used as the centre of the
defended area. The male perches within the entrance and has been seen
to emerge to make a sally a t another which approaches too closely. In
making such a sally he raises and lowers his dorsal fins, flash-displaying
the black, white and orange stripes which are such a marked feature of
them (Petit, 1922, and personal observation). I n most cases the
wanderer retreats without “showing the flag”, but he may, presumably if he is in a state of sexual readiness, challenge, and he may
even drive away the owner of the burrow. While the male perches at
the mouth of one turret the female crouches behind him. How pairing
becomes established is not known. An interesting distraction display
may be seen. On approaching an occupied pair of turrets one individual
may be seen to leave and skitter away, a female will be found resting
quietly within the burrow (cf. drooping wing act of birds).
The eggs are deposited by the female, with the male in attendance,
on the walls of the burrow (de Freitas, unpublished observations). The
story of the completion of hatching and early development has not
been worked out in the field. Kimura (1958) has followed the sequence
in the laboratory and has shown that a typical gobioid larva emerges.