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

SIX
Mating Strategies
The unfortunate couple were embarrassed beyond all mortification, not simply
for having been surprised in the act by the minister, but also for their inability to
separate, to unclasp, to unlink, to undo all the various latches, clamps and sphincters
that linked them together, tail to tail in opposite directions.
—D. Harington, The Cockroaches of Stay More
The genitalia of male cockroaches are frequently used as an example of the extreme complexity
that may evolve in insect reproductive structures (e.g., Gwynne, 1998). They have
been likened to Swiss army knives in that a series of often-hinged hooks, tongs, spikes,
and other lethal-looking paraphernalia are sequentially unfolded during copulation.
Marvelous though all that hardware may be, it has not yet inspired research on its functional
significance. Seventy years ago Snodgrass (1937) stated that “we have no exact information
on the interrelated functions of the genital organs” of cockroaches, and the
situation has improved only slightly since that time. While there is a vast literature on
pheromonal communication, reproductive physiology, male competition, and behavioral
aspects of courtship in cockroaches, we know surprisingly little about the “nuts and
bolts” of the copulatory performance, and in particular, how the male and female genitalia
interact.
Here we briefly describe cockroach mating systems, and the basics of mate finding,
courtship, and copulation. We then focus on just a few topics that are, in the main, relevant
to the evolution of cockroach genitalia. We make no attempt to be comprehensive.
Our emphasis is on male and female morphological structures whose descriptions are
often tucked away in the literature on cockroach systematics and are strongly suggestive
of sperm competition, cryptic mate choice, and conflicts of reproductive interest. One
goal is to shift some limelight to the female cockroach, whose role in mating dynamics is
poorly understood yet whose morphology and behavior suggest sophisticated control
over copulation, sperm storage, and sperm use.
MATING SYSTEM
In nearly all cockroach species studied, males will mate with multiple females even if the
exhaustion of mature sperm and accessory gland secretions preclude the formation of a
spermatophore (Roth, 1964b; Wendelken and Barth, 1987); cockroach mating systems
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