Phylogeny of the Genera of Entomobryidae (Collembola)Based on Nuclear DNA Sequences and Morphology

University Of Vermont & State Agricultural College, Burlington VT

Investigators

Abstract

DEB-0075548 Dr. Felipe Soto-Adames Dr. Felipe Soto-Adames at the University of Vermont has received a grant to study the evolution of a highly unusual group of insects known as springtails (Collembola, non-insect hexapods). Entomobryidae is the largest family of springtails accounting for 21% of all species described in the class. The family has a world wide distribution and in some tropical settings surpasses all other groups in number of species and individuals. Despite this diversity relatively little work has been done to elucidate their evolutionary relationships. This project is aimed at providing the first comprehensive estimate of phylogenetic relationships among genera of Entomobryidae using a data set that combines DNA sequences and morphology. The resulting phylogeny will accomplish three objectives: clarify relationships among the three largest groups of genera; test previous hypotheses suggesting a polyphyletic origin for Paronellidae; and provide a much needed phylogenetic framework for future studies attempting to identify factors contributing to the successful diversification of this family. All genera of Entomobryidae will be examined to complete their morphological descriptions. Because morphological characters alone may not resolve some relationships, this data set will be complemented with DNA sequences from two nuclear genes. Elongation factor 1-alpha (EF1-a) and the small subunit of the ribosome (18S) are very conserved genes which allow rapid and consistent amplification via the polymerase chain reaction even for single individual springtails, some of which are 0.8mm long or less. Despite their high degree of sequence conservation analysis of preliminary data shows that in combination with morphology these genes can resolve relationships at the subfamily level. Resolution of the long standing problems of relationships among genera of Entomobryidae will result in a more stable classification, with more predictive power than the current system. In addition, Dr. Soto-Adames will update the key to genera of Entomobryidae already available in the internet. This key will be an excellent aid for agricultural entomologists given the recent increased use of Collembola as indicators of soil health. Soil biologists will also benefit from clarifications of the taxonomy