The basic function of an intromittent organ seems deceptively simple - it mechanically introduces sperm into a female reproductive tract, thereby increasing a male's probability of fertilization. But male copulatory structures seem to belie this simple function: they are extravagantly diverse and species-specific in form, examples include the long, coiled phalluses of waterfowl; the complex beetle aedeagus; the spiked, smooth, and curlicued penises of mammals; the long rod-like gonopodia of poecilid fish; and paired snake hemipenes, to name a few. Although biologists historically addressed morphological differences among intromittent organs in light of their value as taxonomic characters, more recent studies have begun to examine the selective mechanisms that produce their diverse forms.

Many selective pressures affect intromittent organ anatomy. As copulatory structures they are on the front line of male reproductive strategies, and their functional anatomy is probably under strong natural selection, although some studies have uncovered deep molecular homologies and shared genetic programs that may developmentally limit their diversity of shape. But intromittent organs do not work in isolation: because they interact directly with female structures, their form can also be affected by female reproductive strategies such as cryptic female choice, or by strategies that lead to sexual conflict.

The goal of this symposium is to create a synthetic understanding of the factors that make intromittent organs some of the most morphologically diverse structures in the animal kingdom. We are bringing together scientists who share the common goal of understanding the development, function, and evolution of intromittent organs in the context of reproductive behavior. Speakers will address the varied influences on the evolution of intromittent organs in both vertebrates and invertebrates, including ecological interactions, competing selective pressures, phenotypic plasticity, sexual conflict, life history, genes and development, and the biomechanics of copulation. Speakers will further address some of the potentially far-reaching consequences of genital evolution on reproductive isolation, i.e. speciation. By combining morphological, developmental, and behavioral researchers in one symposium we hope to foster a forward-looking and holistic understanding of the genesis and operation of intromittent organs.

Sponsors: DVM, DCB, DCE, DIZ, and AMS
  
This symposium also received funding from Sewanee: The University of the South

Organizers

• Brandon C. Moore (Sewanee: The University of the South)
• Diane A. Kelly (University of Massachusetts Amherst)

Speakers