Many animals alter their hatching timing in response to environmental cues to risks and opportunities that affect eggs and hatched young. These include diverse invertebrates (from parasitic flatworms to lobsters) and vertebrates (fishes, amphibians, reptiles, and birds). The widespread, common phenomenon of environmentally cued hatching has been studied largely as a series of isolated cases, limiting our understanding of both its diversity and its shared characteristics. An integrative and comparative approach to environmentally cued hatching will improve our understanding of animal reproduction and early life stages. The project is a one-day symposium focused on embryos as organisms that are subject to natural selection and responsive to their environment, and hatching as an ecologically critical transition point. The symposium will be held at the Society for Integrative and Comparative Biology meetings, in Salt Lake City, Utah, on January 6, 2011, and the proceedings published in the journal Integrative and Comparative Biology. The symposium will bring together ten scientists studying hatching timing in animals that respond to a wide variety of environmental conditions, risks, and resources. Associated sessions of contributed posters and talks will expand the range of participants and facilitate interactions between students and established scientists. Speakers will address the ecological context of environmentally cued hatching, the developmental and physiological mechanisms that allow embryos to hatch or to remain in the egg over a range of ages and developmental stages, and the mechanisms connecting environmental cues to the hatching process, including relative roles of embryos and parents. The symposium will build a unified conceptual framework for research on environmentally cued hatching and foster an integrated understanding of both the diversity and commonalities of embryo responses to their environment. It will improve our understanding of the evolution, ecological roles, and mechanisms of hatching plasticity in particular and embryo behavior more generally.
This symposium, held in Salt Lake City, Utah in January 2011, focused on hatching as an ecologically critical transition point in animal lives. It brought together people who study adaptive hatching timing in diverse organisms and many different ecological and functional contexts. Presentations and conversations at the symposium generated a deeper understanding of the evolution, ecological importance, and mechanisms of cued hatching timing, and of embryo behavior more broadly. They led to new connections, research collaborations, and mentoring. The results have been widely disseminated through publication of the symposium papers. Embryos can perceive cues from the environment outside their eggs and may actively alter when they hatch in response to their local conditions. This "environmentally cued hatching" occurs in all classes of vertebrates and in diverse invertebrates; it is much more common than generally appreciated. Cued hatching timing is critically important for understanding how animals survive the challenges facing early life stages. Research in this area integrates many different fields of biology including ecology, evolution, life history theory, developmental biology, physiology, and animal behavior. The broad integrative work of the symposium is important for many areas of biology, evidenced by its sponsorship by the Society for Integrative and Comparative Biology and by five divisions within SICB: Developmental and Cellular Biology, Comparative Physiology and Biochemistry, Evolutionary Developmental Biology, Animal Behavior, and Invertebrate Zoology. A symposium volume for the journal Integrative and Comparative Biology was published in 2011 that included invited papers from the symposium and associated session. No previous attempt had been made to integrate and compare research on hatching plasticity across responses to different environmental factors, such as physical conditions in the habitat, predation risks, and food resources; neither had cued hatching been compared across widely divergent groups of animals. This isolation hampered our understanding of the evolution and mechanisms of adaptive embryo behavior and its ecological importance. The animal diversity represented in the symposium included parasitic flatworms, free-living annelids, molluscs, crustaceans, fishes, amphibians, reptiles, and birds. The speakers presented examples from many different environments, and responses to many cue types, in a variety of ecological contexts. A Round Table Discussion at the end of the symposium addressed important commonalities and differences, and identified critical gaps in our current understanding and promising new directions for research. Invited speakers included Karen Warkentin, Boston University (symposium co-organizer); Karen Martin, Pepperdine University (symposium co-organizer); Sean Doody, Monash University, Australia; Atsushi Ishimatsu, Nagasaki University, Japan; Ian Whittington, University of Adelaide, Australia; John Christy, Smithsonian Tropical Research Institute, Panama; Benjamin Miner, Western Washington University; Fernanda Oyarzun, University of Washington; Richard Strathmann, University of Washington (symposium co-organizer); and Wendy Reed, North Dakota State University. Associated sessions of talks and posters included graduate and undergraduate students, postdoctoral scholars, and additional faculty. The "grand challenges in organismal biology" recently identified by NSF and SICB include two areas of particular relevance to environmentally cued hatching. One challenge is to "understand the organism’s role in organism–environment linkages," including responses to environmental change, mechanisms of resilience/fragility, and responses across time scales from behavior, acclimation, and plasticity to adaptation. Environmentally cued shifts in hatching timing are key mechanisms by which the earliest life stages – which often experience the highest mortality – cope with environmental variation. Improving our understanding of their prevalence, ecological importance, mechanisms and evolution is critical for meeting this challenge. A second "grand challenge" is "understanding how organisms walk the tightrope between stability and change," including a focus on modular organization and inter-modular linkages. A key dimension of modularity is between stages in complex life cycles. Substantial research effort has focused on metamorphosis as a critical transition, and metamorphic plasticity as an important factor allowing organisms to successfully develop through variable environments. Hatching is an equally critical, and more common, life history transition, but the opportunities it creates as a point of individual flexibility are not as well understood or appreciated. Hatching offers excellent opportunities to explore the combination of selective forces, developmental constraints, and multiple layers of mechanisms that shape plastic phenotypic responses to environmental cues. Four of the invited speakers were early career scientists, four were women, and one was Hispanic. One is a postdoctoral scholar, two are assistant professors, three are associate professors, two are professors, one is a senior staff scientist and one is emeritus. One of the co-organizers is from a primarily undergraduate institution. Associated poster and contributed paper sessions expanded the range of participants and facilitated further interactions. Graduate, postdoctoral, and undergraduate students participated in the Round Table Discussion and a mentoring lunch, symposium-associated social events, and additional informal interactions throughout the meeting. Discussions among the participants in the symposium and associated sessions led to new collaborations, unexpected synergisms and insights, and a deeper understanding of embryos as environmentally responsive organisms.
