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

Fig. 6.3 “Basics” of type I courtship and copulation in cockroaches,
after initial orientation to a potential mate.
With few exceptions, pre-copulatory behavior is remarkably
uniform among cockroaches (Roth and Willis,
1954b; Roth and Dateo, 1966; Roth and Barth, 1967;
Roth, 1969; Simon and Barth, 1977a). Antennal contact
with the female usually instigates a male tergal display
(Fig. 6.3); he turns away from her and presents the dorsal
surface of his abdomen. The female responds by climbing
onto his back and “licks” it, with the palps and mouthparts
closely applied and working vigorously. The “female
above” position lasts but a few seconds before the male
backs up and extends a genitalic hook that engages a small
sclerite in front of her ovipositor. Once securely connected,
he moves forward, triggering the female to rotate
180 degrees off his back. The male abdomen untwists and
recovers its normal dorsoventral relationship almost immediately.
The pair remains in the opposed position until
copulation is terminated.
Although the final position assumed by cockroaches in
copula is invariably end to end, there are two additional
behavioral sequences that may precede it. Both are characterized
by the lack of a wing-raising display and female
feeding behavior.
Type II mating behavior is characterized by the male
riding the female, and is known in Pycnoscelus indicus and
Jagrehnia madecassa. After the male contacts the female
he crawls directly onto her back. He twists the tip of his
abdomen down and under that of the female, engages her
genitalia, then dismounts and assumes the opposed position
(Roth and Willis, 1958b; Roth, 1970a; Sreng, 1993).
In type III pre-copulatory behavior, neither sex mounts
the other. After contact is made between the sexes, the
male typically positions himself behind the female with
his head facing in the opposite direction, then moves
backward until genitalic contact is established. Cockroaches
that fall into this category include Gromphadorhina
portentosa (Barth, 1968c), Panchlora nivea (Roth
and Willis, 1958b), Pan. irrorata (Willis, 1966), The. petiveriana
(Livingstone and Ramani, 1978), Panesthia australis
(Roth, 1979c), and the giant burrowing cockroach
Macropanesthia rhinoceros. Mating in the latter has been
described as being “like two Fiats backing into each
other” (D. Rugg, pers. comm. to CAN) (Fig. 6.4). In Epilampra
involucris, the male arches his abdomen down and
then up in a sweeping motion until he contacts the female’s
genitalia (Fisk and Schal, 1981). In Panesthia cribrata,
the two sexes start out side by side. The female
raises the tip of her abdomen and the male bends toward
the female until the tips of their abdomens are in close
proximity. The male then turns 180 degrees to make genital
contact (Rugg, 1987). It is of interest that type III precopulatory
behavior occurs in the Polyphagidae (Therea),
and in four different subfamilies of Blaberidae. A common
thread is that most of these cockroaches are strong
burrowers, suggesting that the behavior may be an adaptation
to some aspect of their enclosed lifestyle. It is also
notable that termites initiate copulation by backing into
each other (Nutting, 1969).
Acoustic Cues
In some cockroach species mating behavior is highly
stereotyped, with an internally programmed, unidirec-
Fig. 6.4 Copulating pair of Macropanesthia rhinoceros, a species
with type III mating behavior. Photo courtesy of Harley
Rose.
92 COCKROACHES