Symposium for the XXI International Congress of Entomology:

"Insects as models for integrating development with evolution"
 

Overview of the importance of Insect Evo-Devo

Rapid advances in development and evolution are providing unprecedented opportunities for synthesis of these fields. The integration of these traditionally disparate approaches has provided fresh insight into biology, improving our capacity to understand the processes of evolutionary change and morphological diversification. With these new perspectives has come a surge in new research and research practitioners, as evidenced by the recent appearance of at least two new journals dedicated to "Evo-Devo", and ever-increasing numbers of research articles and conference presentations. As may be typical for nascent disciplines, the initial participants comprise a collection of researchers with widely divergent expertise and backgrounds. One of the most critical steps in the growth of the field is to foster communication among these researchers, as the insight, feedback, and collaborations that result from such interactions will shape new directions and reveal unanticipated avenues for research. Conference symposia represent unparalleled opportunities for bringing researchers together, as evidenced by the recent (NSF funded) symposium on Evo-Devo at the SICB meetings in Atlanta early this year.

We request funds for defraying travel and conference-related expenses for participants in a similarly integrative symposium to be held at the XXI International Congress of Entomology meetings in August 2000. Our symposium has three goals.

1) To draw attention to the critical role that insect research has played in Evo-Devo. The stunning diversity of insects, the short generation times of many insect species, and the ease with which many insects may be reared in the laboratory have all contributed to their fundamental role in experimental biology. Many of the critical studies that shape our understanding of both development and evolution were conducted with insects. This pivotal role of insect studies makes the absence of prior Evo-Devo symposia at entomological conferences particularly surprising, and illustrates the need for such a precedent.

2) To capitalize on the tremendous breadth of biological expertise in insect science. Although entomology comprises a huge branch of biology (as evidenced by the several thousand attendees at the Entomological Society of America conference this past December), most entomologists do not actively integrate development with evolution, and to our knowledge, no entomology meeting has ever held a symposium on Insect Evo-Devo. By presenting rigorous empirical examples of this nascent discipline at the world's largest entomological gathering, we will provide focus and foundation for future entomological research questions that will bridge the gap between strictly evolutionary and developmental approaches.

3) To present the perspective of young investigators. We deliberately focus on the next generation of research biologists. In many ways, these investigators are the first to attempt to actively master both developmental biology and evolutionary biology. They are developing lifetime research programs at the interface of evolution and development, yet most of them have never met. We feel that fostering interactions and collaborations among these motivated young scientists has the greatest potential for constructively impacting the field.
 
 

Background for the symposium

In the late 1930's, prominent evolutionary theorists, geneticists, paleontologists and systematists convened in an effort to unite their fields under the rubric of the "modern synthesis." Incredibly, the field of developmental biology was not included within this modern synthesis, which resulted in the exclusion of developmental biology from the academic framework that soon emerged as the conceptual foundation for evolutionary biology in the 20th century. In the following years, few attempts were made to re-synthesize the fields of developmental and evolutionary biology. One notable exception was the work of Conrad Waddington on genetic assimilation in insects (specifically fruit flies). His studies were visionary in that he conceived of ontogeny as an inherently flexible process (while developmental biologists typically view ontogeny as highly stereotyped and repeatable; see Bolker & Raff, 1996), and that this flexibility is the key to generating morphological diversity. Perhaps the major force behind the current upwelling of interest in the field of Evo-Devo was work on the homeotic and other patterning genes in fruit flies, and their corresponding orthologues in other widely diverged taxa (such as nematodes and vertebrates). Still, we feel that much of the promise of the nascent field of evolutionary-developmental biology lies not in exploring supposed similarities between widely diverged taxa, but instead in determining the developmental basis for evolutionary differences within more restricted taxonomic groups. This latter approach dates back to the 1960's and 70's, with the work of a handful of researchers such as Père Alberch, Stephen J. Gould and David Wake. In his trailblazing work on plethodontid salamanders, Wake (1966) effectively argued that the evolution of paedomorphosis (differential metamorphosis of various anatomical features) largely determined the evolutionary success of the group. Such a close examination of developmental modifcations in the phylogenetic context of a restricted taxonomic group was radical at that time. We consider this approach to be the most effective model for integrating developmental and evolutionary biology.

Insects represent a fertile ground for such an approach. Insects are by far the most speciose animal group on the planet, and hence represent a vast array of natural experiments in the evolution of form and function. Their rapid life cycles make them amenable to both evolutionary and ontogenetic studies, and the ease with which many insects can be reared under controlled conditions make them ideal foci for laboratory experiments. There is a long and rich history in utilizing insects to address questions in molecular biology and genetics, cell and developmental biology, physiology, behavior, ecology and evolutionary biology. For example, the field of developmental genetics blossomed largely through studies on the fruit fly Drosophila melanogaster, and much of our current understanding of organismal physiology (notably endocrinology) derives from research on lepidopterans (moths and butterflies), hemipterans (true bugs), and other insects. Insects (notably drosophilids, in the work of T. Dobzshansky, T.H. Morgan and others) have also provided much of the experimental and theoretical framework for evolutionary biology in the 20th century. Recently, insects have become an especially favored study group among evolutionary biologists as a whole, as a scanning of the table of contents in any evolution journal will attest.

Still, the current trend among the majority of insect researchers (as is the case among biologists generally) is to maintain a single-discipline approach. Thus, for example, the vast majority of molecular and developmental biologists studying insects are not doing so in an evolutionary context. The same can be said for evolutionary biologists studying insects, who generally have not taken full advantage of the awesome power of insect molecular, genetic and developmental approaches to probe more deeply into their biological questions. Our symposium at the upcoming International Congress of Entomology will bring together an outstanding group of researchers who represent a minority among insect biologists: namely, those who are adopting a dual approach in their research programs.

Holding such a symposium at the largest entomology gathering in the world (which convenes only once every five years) will represent an important step towards introducing such a dual approach to the global entomology community. Ideally, our symposium will attract a diverse audience whose research programs collectively represent great taxonomic and disciplinary breadth. In this way, our symposium can be a catalyst for galvanizing the field of Insect Evo-Devo. By illustrating how an Evo-Devo approach can capitalize on the existing knowledge-base for insect biology, we can shed new light on the startling life history, behavioral and morphological diversity in insects.

We have sought speakers based upon several criteria. First and foremost, we looked to scientists who are truly pursuing research in both evolutionary and developmental biology. The researchers in our symposium use the tools of molecular and developmental biology to explicitly test evolutionary hypotheses. We strongly advocate this approach, since as such, it represents a true scientific discipline.

The second characteristic that guided our search for speakers was taxonomic breadth. Often-times, "Insect Evo-Devo" means comparing fruit flies to nematodes or mice. Our speakers, by contrast, cover a considerable range of different insect taxa (8 insect orders in all). We feel that this is important for several reasons. First, our taxonomically-diverse speaker list will help attract a broader audience for our talks. Second, it will allow us to exploit one of the facets of insects that make them such ideal subjects for Evo-Devo research: namely, the vast morphological, behavioral and life-history diversity in this extraordinary group of animals. And third, it offers the potential of formulating general principles in the evolutionary-developmental biology of insects, paving the way for a more satisfying theoretical framework for Evo-Devo, something which is notably and unfortunately lacking.

The third important attribute of our speaker list is that many are insect researchers in the early stages of their careers. We feel that far too often, high-profile symposia in this and related areas are composed of researchers with well-established reputations. Often times, these researchers present experiments that were designed and performed by their post-docs, graduate students, and less-well-known collaborators. We have gone out of our way to invite these very same post-docs, students and less-well-known researchers for several reasons. First, we find that much of the most exciting research in Insect Evo-Devo is being done by scientists whose graduate training combined a developmental and an evolutionary approach. Until quite recently, such a dual training was a rarity. Second, we simply wanted to give exposure to many less-well-known scientists working in Insect Evo-Devo, as a way of supporting their approaches, which often-times lie well outside the mainstream of typical insect research. And third, we feel that the speakers in our symposium can represent role models to other entomology students and young researchers in attendance at the Congress who may wish to use a multi-disciplinary approach in their own research.

Finally, we have made a significant effort to invite a group of speakers representing a broad ethnic and gender diversity. Two of our invitees are women, and several are non-Caucasians. Furthermore, since the conference is being held in Brazil, we have made a special effort to attract speakers from Latin America, as we recognize that many researchers in these countries are not normally able to attend the Entomology Congress when it is held on other continents.
 
 
 
 

Bolker JA, Raff RA (1996) Developmental genetics and traditional homology. Bioessays 18: 489-94.

Wake DB (1966) Comparative osteology and evolution of lungless salamanders, family Plethodontidae. Memoirs of the Southern California Academy of Sciences 4: 1-111.