Insect Male Genitalia

Among animals with internal fertilization, many species have species-specific male genitalia with morphological divergence among closely related species that is often dramatic and complex. This pattern is especially evident in insects, and male genitalia are considered one of the most important and useful species-diagnostic characters in insect systematics. Recent theoretical developments in genital evolution show that male genitalia are under sexual selection and evolve very rapidly.

My research on the evolution of male genitalia has focused on understanding functional morphology in a comparative framework and I have been promoting the idea that male genitalia are complex organs consisting of several functionally different components that might be under different selective pressures and developmental constraints. Recently, I have begun exploring the use of new imaging technologies (such as micro computer tomography [μ-CT]) to study the functional morphology of male genitalia in unprecedented details using the grasshopper genus Melanoplus, which is known to have highly divergent male genitalia among species. As we understand more about the functions of different genital components, we will be able to tease apart the processes shaping the evolution of these fascinating traits. My ultimate goal in this line of research is to connect functional morphology with genomics in a phylogenetic framework to understand the evolution of one of the most important morphological traits in insect systematics.

Representative Papers:

  • Song, H. and Mariño-Pérez, R. 2013. Re-evaluation of taxonomic utility of male phallic complex in higher-level classification of Acridomorpha (Orthoptera: Caelifera). Insect Systematics & Evolution 44: 241-260.
  • Song, H. and Bucheli, S.R. 2010. Comparison of phylogenetic signal between male genitalia and non-genital characters in insect systematics. Cladistics 26: 23-35.
  • Song, H. 2009. Species-specificity of male genitalia is characterized by shape, size, and complexity. Insect Systematics and Evolution 40(2): 159-170.