CURRENT RESEARCH (BEGINS APRIL 15, 2021)
LIFE CYCLE EVOLUTION IN ROTIFERA: THE INFLUENCE OF SEXUAL REPRODUCTION ON CONTEMPORARY SYSTEMATICS OF MONOGONONTA
PIs: R. Hochberg (UML), EJ Walsh & J Mohl (UTEP), and RL Wallace (RIPON)
Phylum Rotifera comprises the largest lineage of bisexual, microscopic animals in the monophyletic clade Gnathifera. Encompassing some five groups (Chaetognatha, Gnathostomulida, Micrognathozoa, Rotifera, and Acanthocephala), the Gnathifera contains ~3575 species, more than half of which are rotifers. Unlike other gnathiferans, rotifers play important ecological roles as grazers and predators in the microbial loop and classical planktonic food web of freshwater environments. Their life history displays a complex interplay among abiotic and biotic factors that favor some characteristics over others, thus benefiting reproduction of particular species in certain habitats. They also show extraordinary variability in morphology and modes of reproduction. However, evolutionary paths may have constrained reproductive form and function, thereby restricting reproductive flexibility within specific lineages and inhibiting character evolution. Modes of rotifer reproduction includes strictly sexual, strictly asexual (thelytoky), and cyclical parthenogenetic (including arrhenotoky). Cyclical parthenogenesis is found only in subclass Monogononta, the largest clade of free-living rotifers. This clade also shows the greatest reproductive variability, including haplodiploidy, amphoterism, matrotrophy, and male dwarfism. This research will provide the most comprehensive phylogeny of Monogononta, which will advance systematics above the level of genus and provide a framework for testing how lineage diversification is related to reproductive divergence.  Award Abstract 2051684

Sponsored Research Activity
1. National Science Foundation: 2021-2025. Collaborative Research: Life cycle evolution in Rotifera: The influence of sexual reproduction on contemporary systematics of Monogononta. Award Abstract 2051684
2. National Science Foundation: An International Approach to the Biodiversity, Biogeography and Evolution of Caribbean Gastotricha. 2009-2013. PI: R. Hochberg. Award Abstract #0918499
3. National Science Foundation: Collaborative Research: Integrating genetics, life history and morphology into understanding the diversification of an enigmatic metazoan lineage. 2013-2018. Co-PI: R. Hochberg. Award Abstract #1257110
4. National Science Foundation: MRI: Acquisition of a Next Generation Sequencing System for Genomics Research and Training at the University of Massachusetts Lowell. 2014-2017. co-PI: R. Hochberg. Award Abstract #1429212
5. Experiment.com: Xenomorphs of the Arachnida: Whipscorpions and their acid defense. co-PI: R. Hochberg. Abstract.