Cockroache; Ecology, behavior & history - W.J. Bell

low them to expand their dietary repertoire to other
forms of plant litter when required.
In Existing Burrows and Nests
Some cockroaches specialize in using the niche construction,
food stores, and debris of other species. Whether
these cockroaches elude their hosts or are tolerated by
them is unknown. Of particular interest are the cockroaches
that live with insectivorous vertebrates such as
rodents and some birds. How do the cockroaches avoid
becoming prey?
Insect Nests
A number of cockroaches live in the nests of social insects,
although these relationships are rather obscure.
Some cockroach species collected in ant and termite
colonies have been taken only in this habitat (Roth and
Willis, 1960), and are presumably dependent on their
hosts. In others, the relationship is more casual, with the
cockroaches opportunistically capitalizing on the equable
nest climate and kitchen middens of their benefactors.
Several species of the genus Alloblatta, for example, scavenge
the refuse piles of ants (Grandcolas, 1995b). Similar
garbage-picking associations are found in Pyc. surinamensis
with the ant Campanotus brutus (Deleporte et al.,
2002), and in nymphs of Gyna with Dorylus driver ants
(Grandcolas, 1997a). Occasional collections from insect
nests include the Australian polyphagid Tivia australica,
recorded from both litter and ant nests, and the blattellid
Paratemnopteryx australis, collected from under bark, in
litter, and from termite (Nasutitermes triodiae) nests
(Roach and Rentz, 1998). In the United States, Arenivaga
bolliana and A. tonkawa have been taken from both nests
of Atta texana and burrows of small vertebrates (Roth
and Willis, 1960; Waller and Moser, 1990). In Africa, Er.
capensis has been collected in open bush, in human habitations,
and in termite mounds, and is just one of several
taxa, including Periplaneta, that exploit both human and
insect societies (Roth and Willis, 1960).
The records we have of more integrated myrmecophiles
include the New World genera Myrmecoblatta
and Attaphila. The polyphagid Myrmecoblatta wheeleri is
associated with nests of Solenopsis geminata in Guatemala
(Hebard, 1917), and with the carpenter ants Camponotus
abdominalis in Costa Rica and C. abdominalis floridanus
in Florida. Deyrup and Fisk (1984) observed at least 20
Myr. wheeleri of all sizes when a dead slash pine log was
turned over in scrubby flatwoods habitat in Florida. All
Attaphila spp. (Blattellidae) are associated with leaf-cutting
ants in the genera Atta and Acromyrmex (Kistner,
1982). The best known is Attaphila fungicola (Fig. 1.16B),
a species that lives in cavities and tunnels within the fungus
gardens of Atta texana. Both male and female cockroaches
have been collected from A. texana nests in Texas
(Wheeler, 1900), but only females have been collected in
Louisiana (Moser, 1964). Within the nest, Att. fungicola
ride on the backs or the enormous heads of soldiers,
which “do not appear to be the least annoyed” (Wheeler,
1900). The cockroach mounts a passing host by grabbing
the venter or gaster, then climbing onto the mesonotum;
they ride facing perpendicular to the long axis of the ant’s
body. The weight of the cockroach may cause the ant to
topple over (J.A. Danoff-Burg, pers. comm. to WJB). Perhaps
for this reason, Attaphila chooses for steeds the soldiers,
the largest ants in the colony. The cockroaches run
along with ants as well as riding on them, and can detect
and orient to ant trail pheromone (Moser, 1964), presumably
via a unique structure on the maxillary palps
(Brossut, 1976). Wheeler (1900) originally thought that
the cockroaches fed on the ant-cultivated fungus within
the nest, but later (1910) decided that they obtain nourishment
by mounting and licking the backs of soldiers. It
is, of course, possible that they do both.
Recently, another myrmecophile has been described
from jungle canopy in Malaysia, leading us to believe that
there are many more such associations to be discovered
in tropical forests. The ovoviviparous blattellid Pseudoanaplectinia
yumotoi was found with Crematogaster deformis
in epiphytes (Platycerium coronarium) exposed to
full sunlight 53 m above the ground. The leaves of these
stag’s horn ferns form a bowl that encloses the rhizome,
roots, and layers of old leaves within which the ants and
cockroaches live. More than 2800 Ps. yumotoi were collected
from one nest of about 13,000 ants. The ants protect
the cockroaches from the attacks of other ant species.
Living cockroaches are not attacked by their hosts, but
ants do eat the dead ones (Roth, 1995c; T. Yumoto, pers.
comm. to LMR). At least two cockroach species exploit
the mutualism between ants and acacias. Blattella lobiventris
has been found in swollen acacia thorns together
with Crematogaster mimosae (Hocking, 1970). Female
Nyctibora acaciana glue their oothecae near Pseudomyrmex
ant nests on acacias, apparently for the protection
provided by the ants against parasitic wasps (Deans
and Roth, 2003).
Several species of cockroaches in the genus Nocticola
have been found within the nests of termites but nothing
is known about their biology or their relationship with
their hosts (Roth and Willis, 1960; Roth, 2003b). The majority
of these are associated with fungus-growing termites
(Macrotermes and Odontotermes), which in the
Old World are the ecological equivalents of Atta. This
strengthens the suggestion that fungus cultivated by social
insects may be an important dietary component of
cockroach inquilines. Many cockroach species can be
50 COCKROACHES