SICB Annual Meeting 2009
January 3-7, 2009
Boston, MA

Symposium "Evolution of Mechanisms Controlling Timing of Breeding in Animals"
Organized by: Michaela Hau and Tom Hahn


Most terrestrial animals live in seasonal environments where successful reproduction is only possible at certain times of the year. In order to time reproductive events in synchrony with environmental seasonality and thereby maximize fitness, animals possess a sophisticated physiological machinery that acquires environmental information and integrates it with internal signals to regulate reproductive activity. Recently, significant advances have been made in unraveling the physiological and molecular mechanisms that form the basis of the reproductive machinery in mammals and birds. At the same time, new studies in evolutionary ecology are beginning to pinpoint the reproductive phenotypes on which selection acts to produce individuals that breed at an optimal time of year in different habitats.

These recent developments in both fields now provide a unique stepping point at which the two fields ought to be integrated to enhance progress in our understanding of the evolution of reproductive mechanisms. We propose to unite at one venue international experts working on reproductive physiology and molecular endocrinology together with those working in evolutionary ecology and life history to integrate these historically separate fields. Furthermore, we aim to bring together researchers working on a variety of vertebrate taxa, in an attempt to stimulate exchange of ideas across taxonomic groups. Traditionally, physiologists have shied away from understanding the organization of physiological systems from an evolutionary standpoint. Likewise, evolutionary ecologist often do not embrace physiological methods to understand the mechanisms underlying the expression and functioning of reproductive traits. While some integration of these two fields has recently been attempted (for example in the NSF-funded research coordination network on "Integrating Ecology and Endocrinology in Avian Reproduction"), this exchange has been limited to avian taxa. Furthermore, recent findings in both neuroendocrinology and evolution of animal reproduction have surpassed the exchange fostered by this recently terminated network.

Increasing our understanding of the evolution of timing of breeding is becoming increasingly important in times of global climate change, where alterations in weather and ambient temperature have already created a mismatch between the mechanisms that vertebrates use to assess their environment and the actual environmental seasonality. This mismatch has been documented to have detrimental effects on individuals and populations of vertebrates. It is now of utmost importance that the fields of physiology and evolution join forces to understand what may limit or facilitate adjustment (through individual plasticity) or adaptation (through evolutionary change) of reproductive timing to global change.


Michaela Hau
Max-Planck-Institute for Ornithology
Vogelwarte Radolfzell
Schlossallee 2
D-78315 Radolfzell, Germany

Thomas P. Hahn
Section of Neurobiology, Physiology and Behavior
University of California Davis
Davis, CA  95616

Sources of support

- Division of Animal Behavior
- Division of Comparative Endocrinology

List of Speakers

S10.1 Tuesday, Jan. 6, 08:00 MABRY, Karen E: Ecological influences on seasonal (and aseasonal) breeding in brush mice

S10.2 Tuesday, Jan. 6, 08:30 SCHOECH, Stephan J: Food supplementation experiments: A tool to reveal mechanisms that mediate timing of reproduction

S10.3 Tuesday, Jan. 6, 09:00 NUSSEY, D.H.: Plasticity in breeding time in wild vertebrates: a quantitative genetic approach

S10.4 Tuesday, Jan. 6, 09:30 COPPACK, T.: Springing ahead - The evolution and control of avian protandry

S10.5 Tuesday, Jan. 6, 10:30 YOSHIMURA, T.: Molecular and Endocrine Mechanisms of Vertebrate Photoperiodic Response

S10.6 Tuesday, Jan. 6, 11:00 KRIEGSFELD, L.J.*; GIBSON, E.M.; WILLIAMS, W.P.; BENTLEY, G.E.; TSUTSUI, K.: The Circadian Control of Neuroendocrine and Ovulatory Function: Lessons From the Young and Old

S10.7 Tuesday, Jan. 6, 11:30 BENTLEY, GE*; UBUKA, T; MCGUIRE, NL; CALISI, RM; PERFITO, MN; TSUTSUI, K; WINGFIELD, JC: Regulation of Vertebrate Reproduction by GnRH and GnIH

S10.8 Tuesday, Jan. 6, 13:00 PERFITO, Nicole*; ZANN, Richard A.; HAU, Michaela; BENTLEY, George E.: Physiological control of non-seasonal reproduction: opportunistic breeding

S10.9 Tuesday, Jan. 6, 13:30 HEIDEMAN, Paul D.*; PITTMAN, Julian T.: Evolution of neuroendocrine mechanisms that regulate reproduction in white-footed mice (Peromyscus leucopus)

S10.10 Tuesday, Jan. 6, 14:00 HELM, Barbara: Temporal coordination of life cycle stages: An avian chronobiology perspective

S10.11 Tuesday, Jan. 6, 14:30 MACDOUGALL-SHACKLETON, S.A.*; STEVENSON, T.J.; WATTS, H.E.; PEREYRA, M.E.; HAHN, T.P.: The evolution of photoperiod response systems and seasonal GnRH plasticity in birds