Phylogeny of Mantodea- the evolution of a predator

Principle Investigator- Gavin Svenson

Comprising approximately 2,300 described species in 434 genera (Ehrmann 2002), the order Mantodea is a predatory insect group with members occupying a diverse array of widely distributed habitats (Hurd 1999). Mantids have diversified in many characteristics, most notably in morphological and behavioral (hunting strategy) adaptations (Roy 1999). For example, one of the most recognized mantid species, the orchid mantis (Hymenopus coronatus), closely resembles colorful flower peddles, supplying both camouflage and an ideal position to ambush prey. Though considerable effort has been devoted to understanding morphological characters within Mantodea, few studies have investigated them in a phylogenetic context or tested the characters used for grouping currently recognized taxa. The study completed by Svenson & Whiting (2004) is the first molecular phylogenetic analysis of mantid relationships and will serve as a launching point for evolutionary investigation of morphology and behavior.

Studies of mantid evolution are inhibited by considerable conflicts between hypotheses of their taxonomic organization. Though taxonomic studies have been thorough, discrepancies between classifications suggest wide latitude in the character interpretation and their relative importance for grouping taxa. Early systematic work on Mantodea was mainly conducted by Beier (1964 & 1968) and subsequently revised by Ehrmann (2002), Roy (1987), and Wang (1993). Ehrmann’s (2002) organization draws attention to the conflict between alternative taxonomic schemes and highlights the lack of a generally agreed upon natural classification for these insects. As in many insect orders, the current classification of Mantodea has serious deficiencies, but serves as the current best estimate of phylogeny and a foundation for further studies. Clearly, deciphering phylogenetic relationships within Mantodea is a crucial step in any project investigating evolutionary trends within the order.

The diversification and specialization of mantids in ecologically diverse and biogeographically dispersed habitats suggests interesting questions about their morphological and behavioral adaptations. Specifically, is character convergence prevalent in mantids that have independently shifted to similar habitat types? If so, are there biogeographical patterns that suggest independent origins of ecomorphs (habitat dependant morphological adaptations) between continents? What patterns of character correlations are present across Mantodea? Conclusions presented in Svenson & Whiting (2004) indicate that among three categories of hunting strategy (generalist, cursorial, and ambush), multiple independent shifts have occurred from the plesiomorphic state of generalist to the apomorphic state of cursorial. True cursorial mantids (occurring on the ground and actively pursuing prey) hunt mainly in environments such as deserts. Are there morphological characters correlated with this shift? Alternatively, generalist mantids (inhabiting trees and hunting opportunistically) hunt in a broader range of environments suggesting the possibility of fewer character convergences and a greater number of evolutionary optimal solutions. Will there be less character correlation associated with a looser, more advantageous hunting strategy.

This project seeks to accomplish investigation of behavioral and morphological character convergence and biogeographical trends across Mantodea using a thorough phylogenetic analysis. Specifically, the goals of this project are to: Objective I, Reconstruct a comprehensive phylogeny for Mantodea using molecular and morphological characters; and Objective II, Investigate key aspects of mantid behavior, morphology, and ecology and the correlation of characters with evolutionary shifts and biogeographical patterns.

In order to address questions about the early evolution of Mantodea a very important lineage needs to be included in the analysis. This group of mantids is the family Metallyticidae.

Principle Investigator- Gavin Svenson