And her voice now held an objective, almost sterile tone. She was saying, “Dr. Hubbard and I have speculated that some ship brought in the ancestors of the cockroaches you have here. It could have been many, many years ago. These cockroaches may have been living on Yarkie for many roach generations, most likely out in the dump. They breed awfully fast, and I mean ‘awfully’ in every sense of the word. Let me explain that. Fertilization takes place when the male roach inserts the rear of his body—called the cercum—into the rear of the female. He deposits a sac of sperm.” The woman’s voice was that of a lecturer emphasizing a significant detail not to be overlooked. “The female holds this sac in her body intact, sometimes for several months. In other words, she can ‘give birth’ pretty much any time during that period. Out of the egg case, which we call oöthecae, the female can lay ten-­sixteen eggs every five days or so. Perhaps in this Yarkie roach group there are more eggs and quicker hatchings, but even in the common ordinary roach you can see that one mother may mean over a thousand new roaches a year. Given a thousand mothers—and that’s not many at all—you get a million roaches a year just from one group. And so on geometrically.”

Elizabeth put in, respectfully, “But they don’t all survive, of course.”

The other woman nodded. “We’d be overrun everywhere, of course. Normally, many of the young die because the environment is unfavorable—not enough food or moisture, which in turn leads adult roaches, including the parents, to eat the babies. But on this island where the dump provides endless food and shelter, cockroaches like these would thrive.”

Elizabeth had another question, vaguely recalled from a biology course in her sophomore year. “Don’t they have natural enemies that might hold them down?”

The woman inclined her head again. “Yes. For example, certain wasps lay eggs in adult cockroaches. The hatching eggs feed on them and kill them. Then there are symbionts that kill, like the Clostridium botulinium, a form that lives only where there is no oxygen. It develops in the hind gut of the roach . . .”

Elizabeth noted with admiration the easy use of the scientific names and labels. Although she, better than anyone in the room but Peter Hubbard, knew the woman’s­­­­­ professional status, it still seemed unusual for a mouth as lovely as Wanda Lindstrom’s to be uttering the stiff designations. Unusual, impressive, and articulate, Elizabeth acknowledged.