Simanaitis Says

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YESTERDAY, WE GLEANED details of the anole lizards of the Caribbean, as discussed in Elizabeth Pennisi’s report “Meet Lizard Man, a Reptile-Loving Biologist Tackling Some of the Biggest Questions in Evolution.” I personally knew another Lizard Man, Bill MacLean, who was a colleague at the College of the Virgin Islands on St.Thomas in the 1970s. Today in Part 2, we continue with Bill’s tale.

Bill rose from assistant professor to department head to V.P. of Academic Affairs at CVI. He had a species of anolis named in his honor. Also, today there’s a MacLean Marine Science Center at the University of the Virgin Islands.

I last saw Bill and Ellen around 1990 when they visited Wife Dottie and me briefly here in California. Bill was in remission from cancer, and they were on their way to exploring the islands of the South China Sea. Bill died October 15, 1991, at the N.I.H. Hospital in Bethesda, Maryland.

Bill would have been fascinated by Elizabeth Pennisi’s article concerning evolution’s effect on island-dwelling lizards.

Image from

My Own Modest Contribution. Back in the early 1970s, Bill got me interested in mathematical biology, specifically the modeling of predator/prey dynamics. In this case, the predators were various anolis lizard species (there are hundreds).

We had a fairly robust computer at CVI in those days and I had essentially unlimited use of it. Before long, I was devising a program that modeled predator/prey dynamics. Three characteristic outcomes are a stable, possible cyclic one; an eventual demise of the prey, or a demise of the predator.

A periodic outcome with specific age distributions of predator and prey. Illustration from Predator/Prey Dynamics with Age Distributions; Preliminary Report, D.J. Simanaitis and William P. MacLean, Ninth Annual Symposium on Some Mathematical Questions in Biology, 1975.

Standard models like the classical Lotka-Volterra equations treat the predator and prey as unities. Bill and I thought it would be fun to split them into age groups. After all, kiddy lizards are less successful in finding prey than adults. Older prey may be more susceptible to capture than more agile young ones.

Bill explored this thesis by studying age-specific predator/prey in the islands near St. Thomas. Occasionally I’d go along with him, sailing to his test cays where he’d capture and examine different anolis of different age groups in contrasting settings. As described so brilliantly in the Elizabeth Pennisi’s Science article, some Anoles are tree dwellers, others live in the bush.

We worked up a paper on this, Predator/Prey Dynamics with Age Distributions; Preliminary Report. Bill was kind enough to let me have my 15 minutes of fame, 2:40–2:55 p.m., January 29, 1975, at the Ninth Annual Symposium on Some Mathematical Questions in Biology, New York City, New York.

I recall the paper generated only modest interest at the meeting. It was a thrill for me, though, being my first presentation at a national meeting of any sort (in my second career, a good number of SAE papers were to follow).

My only copy of the paper, I forget why now, was assembled years ago by Daughter Suz. I treasure it.

Apparently Daughter Suz worked on this assignment at St. Thomas Montessori School.

I’m confident Bill MacLean would commend Science writer Elizabeth Pennisi and Daughter Suz for jobs well done. ds

© Dennis Simanaitis,, 2020

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