314
found associated with compensation sac in female polymorphs of C . hyalina , suggesting a possible mechanism for
oviposition through the genital pore. Sperm-like bodies have
been found inside the ooecial coelomic cavity in
C . hyalina , supporting the idea that sperm can travel through
the colony (discussed in Chap. 1 ). Additionally, an unknown
intracellular parasite was encountered in oocytes of
C . annulata .
Recent Works
Apart from the above-mentioned works of Hughes and coauthors, among recent publications there are several works by
Ryland and Porter with coauthors (Ryland and Porter 2000 ,
2006 ; Ryland 2001 ; Porter et al. 2001 ; Porter 2004 ; Porter
and Hayward 2004 ; Kuklinski and Porter 2004 ) on the ctenostome genus Alcyonidium . The authors distinguished the
type of reproductive pattern by the presence of intertentacular organs, lipid globules in autozooids or brooded embryos
in thirteen congeneric species, revealing some unusual
aspects of their reproductive biology. For instance, in several
species numerous small eggs were recorded in the absence of
an intertentacular organ. Either the intertentacular organ was
not found, or it is completely lacking in these species and
eggs are spawned through the supraneural pore. However,
although oviparous species with a supraneural pore are
known among Ctenostomata, there are none in Alcyonidium .
In Alcyonidium disciforme , only one embryo per time is
brooded in the tentacle sheath, although several embryos are
a rule for that genus.
Smith et al. ( 2003 ) investigated reproduction in the ctenostome Pottsiella erecta . An ovary develops on the cystid wall
and spermatogenic tissue on the funiculus. Because both
gonads appear in close proximity in the middle region of
zooids that are simultaneous hermaphrodites, the authors
erroneously inferred self-fertilization in this species, which
is obviously not the case (see above). The most intriguing
fi nding was that the egg (occasionally two) is brooded externally in a sticky coat connected with to the maternal zooid by
a fl exible, elastic strand. The authors considered the coat a
fertilization envelope and the strand mucoid. The embryo
remains outside the parent whether the polypide is extended
or withdrawn, and the strand possibly lengthens with time.
A substantial body of experimental work on the reproductive biology of Bugula neritina and Watersipora subtorquata
was undertaken by Marshall and coauthors (Marshall et al.
2003 ; Marshall and Keough 2003 , 2004a , b , 2006 , 2008a ,
2009 ; Allen et al. 2008 ; Marshall 2008 ; Burgess et al. 2009 ;
see also Marshall and Uller 2007 , Elkin and Marshall 2007 ,
Marshall and Keough 2008b , and Marshall et al. 2008
for general review and discussion). This wide research
encompasses different aspects of larval, post-settlement and
colonial performance and one of the most intriquing discoveries was the prolonged effect of larval size on colony life.
Colonies that developed from larger larvae survived better,
grew faster and reproduced sooner or formed more offspring
than those from smaller larvae. This effect was observed over
several consecutive generations.
Experiments of Johnson ( 2010 ) confi rmed that selffertilization is possible in isolated colonies of Bugula stolonifera . Such colonies produced viable larvae that successfully
completed metamorphosis, but overall reproductive fi tness
was less than in control colonies and these larvae experienced
reduced rates of initiation and completion of metamorphosis.
Also the colonies that developed from such larvae in the fi eld
showed decreased survival and reproductive fi tness.
Yagunova and Ostrovsky ( 2010 ) studied the fecundity of
the cheilostome Cribrilina annulata living on stones and red
algae, showing that it reproduces more actively (starts reproduction at a smaller size and forms more ovicells) on an algal
substratum.
Five more papers recently published by the author of this
monograph, with coauthors, were devoted to various aspects
of the evolution of bryozoan gonopores (Ostrovsky and
Porter 2011 ) and placental analogues (Ostrovsky et al. 2009 ;
Ostrovsky and Schwaha 2011 ; Moosburgger et al. 2012 ;
Ostrovsky 2013 ). All are discussed in detail in Chaps. 1 and
3 of the main text.
Chronological list of papers and gymnolaemate species in which different aspects of sexual reproduction
were studied or observed
(works merely presenting data on reproductive ecology
and brood-chamber structure are not included in this list)
Grant ( 1827 )
Carbasea carbasea (Ellis and Solander, 1786) (as Flustra )
(Flustridae)
Flustra foliacea (Linnaeus, 1758) (Flustridae)
Thompson ( 1830 )
‘ Vesicularia ’ (Ctenostomata)
Milne-Edwards ( 1836 )
‘Cellariae’ (Cheilostomata)
Farre ( 1837 )
Alcyonidium duplex Prouho, 1892 (as Halodactylus diaphanus )
(Alcyonidiidae)
Walkeria uva (Linnaeus, 1758) (as Valkeria cuscuta )
(Walkeriidae)
Bowerbankia imbricata (Adams, 1798) (as B . densa )
(Vesiculariidae)
Electra pilosa (Linnaeus, 1767) (as Membranipora )
(Electridae)
Nordmann ( 1839 )
Tendra zostericola Nordmann, 1839 (Tendridae)
Kölliker ( 1841 )
Alcyonidium sp. (as A . gelatinosum Johnston) (Alcyonidiidae)
Appendices
found associated with compensation sac in female polymorphs of C . hyalina , suggesting a possible mechanism for
oviposition through the genital pore. Sperm-like bodies have
been found inside the ooecial coelomic cavity in
C . hyalina , supporting the idea that sperm can travel through
the colony (discussed in Chap. 1 ). Additionally, an unknown
intracellular parasite was encountered in oocytes of
C . annulata .
Recent Works
Apart from the above-mentioned works of Hughes and coauthors, among recent publications there are several works by
Ryland and Porter with coauthors (Ryland and Porter 2000 ,
2006 ; Ryland 2001 ; Porter et al. 2001 ; Porter 2004 ; Porter
and Hayward 2004 ; Kuklinski and Porter 2004 ) on the ctenostome genus Alcyonidium . The authors distinguished the
type of reproductive pattern by the presence of intertentacular organs, lipid globules in autozooids or brooded embryos
in thirteen congeneric species, revealing some unusual
aspects of their reproductive biology. For instance, in several
species numerous small eggs were recorded in the absence of
an intertentacular organ. Either the intertentacular organ was
not found, or it is completely lacking in these species and
eggs are spawned through the supraneural pore. However,
although oviparous species with a supraneural pore are
known among Ctenostomata, there are none in Alcyonidium .
In Alcyonidium disciforme , only one embryo per time is
brooded in the tentacle sheath, although several embryos are
a rule for that genus.
Smith et al. ( 2003 ) investigated reproduction in the ctenostome Pottsiella erecta . An ovary develops on the cystid wall
and spermatogenic tissue on the funiculus. Because both
gonads appear in close proximity in the middle region of
zooids that are simultaneous hermaphrodites, the authors
erroneously inferred self-fertilization in this species, which
is obviously not the case (see above). The most intriguing
fi nding was that the egg (occasionally two) is brooded externally in a sticky coat connected with to the maternal zooid by
a fl exible, elastic strand. The authors considered the coat a
fertilization envelope and the strand mucoid. The embryo
remains outside the parent whether the polypide is extended
or withdrawn, and the strand possibly lengthens with time.
A substantial body of experimental work on the reproductive biology of Bugula neritina and Watersipora subtorquata
was undertaken by Marshall and coauthors (Marshall et al.
2003 ; Marshall and Keough 2003 , 2004a , b , 2006 , 2008a ,
2009 ; Allen et al. 2008 ; Marshall 2008 ; Burgess et al. 2009 ;
see also Marshall and Uller 2007 , Elkin and Marshall 2007 ,
Marshall and Keough 2008b , and Marshall et al. 2008
for general review and discussion). This wide research
encompasses different aspects of larval, post-settlement and
colonial performance and one of the most intriquing discoveries was the prolonged effect of larval size on colony life.
Colonies that developed from larger larvae survived better,
grew faster and reproduced sooner or formed more offspring
than those from smaller larvae. This effect was observed over
several consecutive generations.
Experiments of Johnson ( 2010 ) confi rmed that selffertilization is possible in isolated colonies of Bugula stolonifera . Such colonies produced viable larvae that successfully
completed metamorphosis, but overall reproductive fi tness
was less than in control colonies and these larvae experienced
reduced rates of initiation and completion of metamorphosis.
Also the colonies that developed from such larvae in the fi eld
showed decreased survival and reproductive fi tness.
Yagunova and Ostrovsky ( 2010 ) studied the fecundity of
the cheilostome Cribrilina annulata living on stones and red
algae, showing that it reproduces more actively (starts reproduction at a smaller size and forms more ovicells) on an algal
substratum.
Five more papers recently published by the author of this
monograph, with coauthors, were devoted to various aspects
of the evolution of bryozoan gonopores (Ostrovsky and
Porter 2011 ) and placental analogues (Ostrovsky et al. 2009 ;
Ostrovsky and Schwaha 2011 ; Moosburgger et al. 2012 ;
Ostrovsky 2013 ). All are discussed in detail in Chaps. 1 and
3 of the main text.
Chronological list of papers and gymnolaemate species in which different aspects of sexual reproduction
were studied or observed
(works merely presenting data on reproductive ecology
and brood-chamber structure are not included in this list)
Grant ( 1827 )
Carbasea carbasea (Ellis and Solander, 1786) (as Flustra )
(Flustridae)
Flustra foliacea (Linnaeus, 1758) (Flustridae)
Thompson ( 1830 )
‘ Vesicularia ’ (Ctenostomata)
Milne-Edwards ( 1836 )
‘Cellariae’ (Cheilostomata)
Farre ( 1837 )
Alcyonidium duplex Prouho, 1892 (as Halodactylus diaphanus )
(Alcyonidiidae)
Walkeria uva (Linnaeus, 1758) (as Valkeria cuscuta )
(Walkeriidae)
Bowerbankia imbricata (Adams, 1798) (as B . densa )
(Vesiculariidae)
Electra pilosa (Linnaeus, 1767) (as Membranipora )
(Electridae)
Nordmann ( 1839 )
Tendra zostericola Nordmann, 1839 (Tendridae)
Kölliker ( 1841 )
Alcyonidium sp. (as A . gelatinosum Johnston) (Alcyonidiidae)
Appendices