Examining Tegmina Polymorphism in Leaf-Masquerading Katydids (Orthoptera: Tettigoniidae)


  • Bethany Mikles Texas A&M University
  • Hojun Song Texas A&M University


Insects employ a wide array of defensive mechanisms to avoid predation in the wild, evolving highly complex strategies for mimicking a wide range of organisms from other predators to surrounding foliage in the environment, all in an attempt to handicap predators’ ability to maintain a clear record of prey images to hunt. Cryptic insect species often evolve further mimicry strategies such as polymorphs and masquerade in order to provide a far more diverse range of forms, with even further variation of form seen through sexual dimorphism. Frequent and complex instances of polymorphism and cryptic masquerade can be found within the Orthopteran subfamily pterochrozinae (Orthoptera: Tettigoniidae), often posing taxonomic dilemmas as the hugely diverse and convincing forms are unable to be distinguished from eachother. This subfamily contains the genus Mimetica whose precision and accuracy in mimicking leaf appearance, as well as the wide diversity in shape and high color variation, make it an ideal system for observing of polymorphic variation of leaf forms. This experiment attempted to clarify the species relationships within Mimetica, in addition to developing a deeper understanding of the function and importance of polymorphs in insect populations and ecological phenomena in order to ascertain if the katydid species incisa, crenulata, viridifolia, mortuifolia, tuberata, and simoni within Mimetica display a distinct number of cryptically polymorphic forms versus continuous variation by utilizing digital landmark based geometric morphometric software to analyze the tegmina. Tps analyses provided strong support for the existence of sexually dimorphic forms for all species, and a lack of distinction in form within all incisa specimens, suggesting a more effective polymorph. In contrast, simoni and viridifolia specimens displayed the clearest distinction in form, supporting the possibility of the existence of discrete polymorphs in this genus but requiring further refined morphometric analyses.