Planet of the Bugs: Evolution and the Rise of Insects (34 page)

Research for this book was supported in part by a grant from the Wyoming NASA Space Grant Consortium, NASA grant #NGT–40102, and by Wyoming NASA EPSCoR NASA Grant #NCC5–578. My research grants from the National Science Foundation, Caterpillars and Parasitoids in the Eastern Andes of Ecuador, allowed me the opportunity to study, think, and write in the Andes highlands.

Over the years the ideas expressed here have been developed, discussed, and refined in several classes I’ve taught, especially Cosmology of Life, Insect Biology, Insect Classification, Insect Evolution, Aquatic Insects, Biodiversity, and Tropical Ecology. Hundreds of students have attended my lectures, and I thank them all for their patience, interest, and insights during this journey. In particular, I wish to thank Samin Dadelahi, Jen Donovan, Olivia Engkvist, and Nina Zitani for uniquely thoughtful discussions of my ideas, and, most importantly, for encouraging me to continue writing. Nina and Jen were the very first people to read the manuscript cover to cover, and the final book, although greatly metamorphosed from those earlier incarnations, is much improved by their attention to detail and enthusiasm for the subject.

My eldest brother, Ted, I thank for giving me my first insect net and loaning me his telescope. My father, Edward B. Shaw, I wish to thank for designing bigger and better insect nets and for collecting expeditions as numerous as the stars and insects. My mother, Vesta, I thank for allowing me to play with glass jars, poisonous chemicals, and especially for letting me bring live insects into the house. My brother, Tim, and my Uncle Lawrence (Latzy) McKay, I thank for introducing me to the genre of science fiction and inspiring me to bring science into the public domain.

When I started college at Michigan State University in 1973, my first declared major was astrophysics. I studied astronomy and learned about stellar evolution, the life and death of stars. But ultimately
my childhood interest in insects won out, and I switched my major to entomology. Professor Roland Fisher was responsible for rekindling my interest in insects through his inspirational lectures, and he showed me what I wanted to do with my professional career. Professors Fred Stehr and Rich Merritt contributed immensely to fueling my passion for the study of insects. During my graduate studies, Professor Charles Mitter at the University of Maryland taught me not to be satisfied with the study of one discipline. While at Harvard University from 1984 to 1989, several individuals were influential. I wish to thank Professor Edward O. Wilson for inspiring me to study the social insects and tropical ecosystems and for deepening my appreciation for earth’s biodiversity. He demonstrated the determination needed to be a successful writer and helped me through difficult times. He also provided me with inspirational advice on writing and publishing, without which I probably wouldn’t have had the energy, direction, or determination to finish this manuscript. Professor Wilson is truly a gentleman and a scholar. Emeritus Professor Frank Carpenter was also inspirational and led me to study fossil insects. His generous contribution of fossil insect photographs allowed me to teach my first class on insect evolution. While at Harvard I also attended many lectures by Professor Stephen Jay Gould and read his popular natural history books. He profoundly influenced my worldview and my teaching style and demonstrated better than most how enthusiastically science can be related to the public.

From the University of Wyoming, I wish to thank Professors Greg K. Brown, Ron Canterna, Mark Lyford, and Terry Roark for providing knowledge, advice, books, information, comments, and encouragement. I also wish to thank the UW Berry Biodiversity Conservation Center, directed by Carlos Martinez del Rio, which contributed to the costs of the color plates. I’m very grateful to Dr. Danita Brandt (Invertebrate Paleontology, Department of Geological Sciences, Michigan State University) for her thoughtful technical and editorial notes on
chapter 2
and for graciously allowing me to outline her research in that chapter. Dr. Conrad Labandeira (Smithsonian Institution) and Dr. Michael Engel (University of Kansas) both thoughtfully read
chapter 5
and made many helpful suggestions. Dr. Douglas H. Erwin (Smithsonian Institution) graciously read
chapter 6
, which relies heavily on his pioneering research on that subject. Brandon Drake
carefully proofread
chapter 8
and contributed to my more accurate depictions of dinosaurs.

I wish to thank the following people for generously contributing photographs of living insects and other arthropods: Jennifer Donovan-Stump (Trinity School, New York, New York), Dr. Janice Edgerly-Rooks (Santa Clara University, California), Andy Kulikowski (Casper, Wyoming), Kevin Murphy (Irish Wildlife Photography, Westport, Ireland), Kenji Nishida (Monterverde, Costa Rica), Angela Ochsner (Torrington, Wyoming), David E. Rees (Timberline Aquatics, Fort Collins, Colorado), and Dr. Barbara Thorne (University of Maryland, College Park). Images of insects in amber were kindly contributed by Dr. Vincent Perrichot (Université de Rennes, France) and Dr. George Poinar Jr. (Corvallis, Oregon). The following people assisted with obtaining permission to publish images of insect fossils: Dr. Olivier Bethoux and Aurélie Roux (Muséum national d’Histoire naturelle, Paris, France) and Dr. Brian Farrell, Dr. Philip Perkins, Amie Jones, and Catherine Weisel (Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts). Marlene L. Carstens (University of Wyoming Photo Services) assisted with the production of digital images from black and white negatives. Helmuth Aguirre, my graduate assistant, kindly helped with the arrangement of images into plates.

I especially wish to thank Professor Paul E. Hanson at the University of Costa Rica for years of friendship and kind assistance with local arrangements for travel to La Selva Biological Research Station and San Ramon Biological Reserve, which inspired parts of this book. Paul, you really helped me “get my feet wet” in the tropics, for which I am very appreciative.

I owe the greatest debt of gratitude to my editor at the University of Chicago Press, Christopher Chung, for seeing merit in my writing and patiently working with me, providing thoughtful and detailed comments, and helping me to reshape my bulky manuscript into a sleeker and immensely more readable book. All my readers will benefit from Christopher’s vision and hard work. Mary Gehl copyedited the final manuscript and made many insightful suggestions and corrections.

Stephen King I thank for his published thoughts about time travel and the craft of writing. Jane Auel I thank for her inspirational lecture at the University of Wyoming about her history as a writer. Many
thoughtful people provided inspiration, helpful suggestions, information, and corrections; any errors that remain are my own.

I hope this book inspires the next generation of bug hunters with the same passion that my first butterfly net infused into me.

Finally, I wish to thank my wife, Marilyn, and my sons, Matthew and Michael. It’s not easy living with an aging, distracted, and absent-minded entomology professor. Sometimes it’s been hard to pay attention at the dinner table when I was trying to work out the history of the earth in the back of my mind. Your love and support through this process has been crucial, and I am profoundly grateful.

About the Author

Scott R. Shaw was born in Detroit, Michigan, in 1955. He started collecting insects at the age of 4. From 1973 to 1978 he attended Michigan State University where he studied astrophysics and entomology. He attended the University of Maryland from 1979 to 1984, where he obtained MS and PhD degrees in entomology. From 1984 to 1989, he worked at Harvard University in the Museum of Comparative Zoology. Since 1989, he has lived in Laramie, Wyoming, where he is professor of entomology at the University of Wyoming and Insect Museum curator. Professor Shaw has discovered and named 163 new insect species (mostly wasps) from 29 different countries. Fifteen insect species have been named after him by other scientists. He has published more than 114 scientific articles about insect classification and evolution. He has named insect genera (
Betelgeuse, Rigel, Orionis
) after stars in the sky and stars of late night television (
Marshiella lettermani
, a wasp named for David Letterman). His published suggestion for a Wyoming state insect, Sheridan’s green hairstreak butterfly, was adopted by the Wyoming legislature and the governor in 2009. He has extensively studied insects in Costa Rica and Ecuador. This is his first book.

Notes

CHAPTER ONE

1
. Many people are surprised to learn how much we still do not know about life on our own planet. We don’t even know how many species we share the world with. Estimates range from seven million to a hundred million, and most biologists would agree that the vast majority of unknown species are insects living in the canopies of tropical forests.

2
. E. O. Wilson, 1990. “First word,”
Omni
, September, 6, 1990,
Academic Search Premier
, EBSCO
host
(accessed November 19, 2013).

3
. David M. Raup,
Extinction: Bad Genes or Bad Luck?
(New York: W. W. Norton, 1991), 14.

CHAPTER THREE

1
. However, expect them to live a long time. My colleague Nina Zitani’s pet millipede lived for nearly twelve years.

2
. The latest molecular studies of fungi suggest that the major lineages of fungal diversity evolved in tandem with the diversification of early vascular plants and terrestrial ecosystems. Fungal diversification certainly contributed to the evolution of microbial soils suitable for the colonization of land plants, and fungi also contributed to the diets of scavenging arthropods such as millipedes and symphylans. You can read more about fungal evolution in Robert Lücking, Sabine Huhndorf, Donald H. Pfister, Eimy Rivas Plata, and H. Thorsten Lumbsch et al., “Fungi Evolved Right on Track,”
Mycologia
101 (2009): 810–22.

CHAPTER FOUR

1
. I use the term “stroll” only artistically here. Recent research on the 360-million-year-old amphibian,
Ichthyostega
, suggests that it just inched along by bending and straightening its back. The earliest amphibians probably dragged their hind legs and tail.

2
. According to my colleague, engineering professor John McInroy, there is a fundamental reason to use six legs. With six legs it is possible to translate and rotate in all three directions. Also, six-legged creatures can resist forces and torques in all directions. The stability of six legs is well known in the field of robotics. For more
on walking robots, see Jean-Pierre Merlet,
Parallel Robots
(Dordrecht: Springer, 2005).

3
. Perhaps I should point out that moving their legs three at a time is the way insects walk or run on a flat surface. Insects, because of their very small size, are also able to walk on vertical and even inverted surfaces. Recent research by S. N. Gorb indicates that they walk a bit more carefully on inverted surfaces. A fly on the ceiling moves slowly and carefully, leaving four legs planted and repositioning only two legs at a time. Upside-down walking on inverted surfaces is possible because insects are so small that the forces of surface tension and cohesion are proportionally greater. Attachment to both smooth and rough surfaces is improved by a variety of microscopic adaptations at the tip of the insect foot, including claws, hairy pads, and adhesive secretions. These characteristics were probably not present in the very earliest terrestrial hexapods, but were developed and refined in the lineages of flying insects over hundreds of millions of years. See S. N. Gorb, “Uncovering Insect Stickiness: Structure and Properties of Hairy Attachment Devices,”
American Entomologist
51 (2005): 31–35.

4
. Although
Rhyniella praecursor
is the oldest undisputed hexapod, most entomologists do not consider the springtails to be true insects. They have very distinctive and unusual retracted mouthparts and appear to be a lineage of hexapods that diverged early from the line leading to most modern insects. However, older entomologists often called any six-legged arthropod, including springtails, an insect.

5
. Until fairly recently, the archeognathans were combined with the silverfish and firebrats into a larger order called Thysanura, a name that is now being abandoned but that persists in some field guides and older literature. The extinct order Monura was described to include similar species that had only one bristlelike tail. Recent entomologists treat the monurans as members of the order Archaeognatha.

CHAPTER FIVE

1
. This is an example of what ecologists call lekking behavior.

2
. I’m taking artistic liberty with the mayfly story. While we are fairly certain that the mayflies, or at least the stem group of mayfly-like insects, first evolved in the Carboniferous years, we do not know for sure exactly when this line of insects first evolved freshwater, aquatic immature stages. They may not have done so until the Permian or even the Triassic years. But I’m guessing that they did go aquatic during the Carboniferous because of the age’s abundant wetlands and the resource advantages of moving first into the freshwater niches. If freshwater fish existed then, it seems reasonable to assume there must have been aquatic insect naiads for them to consume.

3
. Lepidosaurian reptiles were gliders during the Triassic period, with forms similar to today’s Southeast Asian
Draco
. They may have been some of the earliest vertebrates to pursue and feed on winged insects in the air.

4
. Cordaites plants had strap-shaped, broad-leaved foliage, as well as cones, and are considered to be closely related to the earliest conifers.