Determination of Developmental Modules and Conservatism in the Fore- and Hind-wings of Two Species of Dragonflies, Orthetrum sabina and Neurothemis ramburii

The wings of dragonflies are highly compartmentalized as shown by the major and minor veins separating the different compartments or modules. There is a long term hypothesis that compartments of the wings as bounded by the veins may correspond to units of "gene regulation". Are the different compartments 'units of gene regulation' and is there genetic conservatism on the wings of the dragonfly? This study was therefore, conducted to evaluate whether there is a number and pattern of developmental modules in dragonfly wings and determine whether there exists genetic conservatism based on intra and inter-modular variations in the wings. The study was conducted in two cosmopolitan species of Libellulid dragonflies. Different hypotheses were formulated and tested as to the possible spatial boundaries based on major wing venations. A priori models applying the tools of geometric morphometrics were constructed and statistically tested for the goodness of fit test (GoF) statistic by comparing the observed and expected covariance matrices. Jackknife support values for each variational model were also computed using gamma* as the GoF statistic. Results showed fair consistency in the observed number and patterns of hypothesized developmental modules implying that the wings of these species of dragonflies are highly conserved. It is concluded that there is genetic conservatism in the morphological spaces in the wings of the two species. (C) 2011 Friends Science Publishers