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

tional sequence of acts (Bell et al., 1978); in others, malefemale
interaction is more flexible (Fraser and Nelson,
1984). Variations that do occur often take the form of
behaviors that produce airborne or substrate-borne vibrations,
particularly when males are courting reluctant
females (Fig. 6.5). These signals typically occur after
antennal contact but prior to full tergal display, and
include rocking, shaking, waggling, trembling, vibrating,
pushing, bumping, wing pumping, wing fluttering,
“pivot-trembling,” anterior-posterior jerking, hissing,
whistling, tapping, and stridulation. Although Barth
(1968b) suggested that vibrating and wing fluttering during
courtship produce air currents that serve to disseminate
pheromone, very little is known regarding the role of
these behaviors in influencing female receptivity. Hissing
during courtship is best known in G. portentosa (Fraser
and Nelson, 1984), but occurs in other species as well.
Males of Australian burrowing cockroaches pulse the abdomen
during courtship, and the behavior is accompanied
by an audible hiss in the larger species (D. Rugg, pers.
comm. to CAN). Elliptorhina chopardi males produce
broad-band, amplitude-modulated hisses like G. portentosa,
but also complex, bird-like whistles; dual harmonic
series warble independently from the left and right fourth
spiracle (Fraser and Nelson, 1982; Sueur and Aubin,
2006). The common name of Rhyparobia maderae is the
“knocker” cockroach, because of the male habit of tapping
the substrate with his thorax in the presence of potential
mates (Fig. 6.5B). Highly developed stridulating
organs are found on the pronotum and tegmina of some
Blaberidae (Oxyhaloinae and Panchlorinae) (Roth and
Hartman, 1967; Roth, 1968c). Males of Nauphoeta cinerea
use the structures to produce characteristic phrases consisting
of complex pulse trains and chirps if a female is
unresponsive to his overtures (Hartman and Roth, 1967a,
1967b). There is currently no evidence, however, that the
male’s distinctive song (Fig. 6.5D) influences her response.
Sounds produced by N. cinerea during courtship
can be recorded from the substrate on which they are
standing as well as by holding a microphone at close range
(Roth and Hartman, 1967). Given the evidence that cockroaches
can be sensitive to vibration as well as airborne
sound (Shaw, 1994a), substrate-borne courtship signals
may be more common than is currently appreciated. This
is especially relevant for tropical cockroaches that perch
at various levels in the canopy during their active period.
Bell (1990) noted that cockroaches on leaves can detect
the vibrations of approaching predators. These cockroach
species also have potential for communicating with
each other via leaf tremulation. The cockroach “ear”is the
subgenual organ on the metathoracic legs, a fan-shaped
structure lying inside and attached to the walls of the tibiae.
The subgenual organ of P. americana is one of the
Fig. 6.5 Oscilloscope records of sounds in cockroaches. (A)
Arrhythmic rustling sound made by a courting male Eublaberus
posticus; (B) sound produced by a male Rhyparobia
maderae tapping upon the substrate, which in this case, was a
female on which the male was standing; (C) courting sounds
produced by a male Diploptera punctata by striking the wings
against the abdomen; (D) phrase produced by stridulation
during courtship in male Nauphoeta cinerea; compare to (E)
disturbance sound made by male N. cinerea. After Roth and
Hartman (1967); see original work for reference signals and
sound levels.
most sensitive known insect vibration detectors (Autrum
and Schneider, 1948; Howse, 1964).
Length of Copulation
The length of copulation is variable in cockroaches, both
within and between species. In successful matings, the
male and female commonly remain in the linear position
for 50–90 min, but length can vary with male age, the
time since his last mating, and his social status. The shortest
recorded copulations are in the well-studied N.
cinerea. A male’s first copulation is his shortest, ranging
from 9.5 (Moore and Breed, 1986) to 17 (Roth, 1964b)
min. Dominant males of this species copulate significantly
longer than do their subordinates (Moore and
Breed, 1986; Moore, 1990). If males 14–15 days old are
consecutively mated to a series of females, they remain in
copula 22 min during the first mating, 100 in the second,
and 141 in the third (Roth, 1964b). The most extended
matings reported from natural settings are those of Xestoblatta
hamata, where copulation in the rainforest may last
for up to 5 hr (Schal and Bell, 1982), and Polyzosteria limbata,
where copulation occurs in daylight and pairs sometimes
remain linked for over 24 hr (Mackerras, 1965a).
Spermatophores
In all cockroach species the male transfers sperm to the
female via a spermatophore; it begins forming in the male
as soon as the mating pair is securely connected (Khalifa,
1950; van Wyk, 1952; Roth, 2003a). When it is complete,
the spermatophore in Blattella descends the ejaculatory
MATING STRATEGIES 93