Tardigradology

Kenta Sugiura

杉浦 健太

Assistant professor, Systematic Zoology Laboratory, Tokyo Metropolitan University

Research Aim

A wide diversity of organisms inhabit the Earth, among which tardigrades are notable for their exceptionally broad distribution. My study focuses on understanding the diversity and reproductive biology of tardigrades.

(1) What species of tardigrades exist on this little planet?
Tardigrades inhabit environments ranging from suburban areas in Japan to the Arctic and Antarctic regions. This research investigates species differences across regions and habitats by collecting specimens from various locations, including field sampling during travel and surveys in high-altitude environments. Sampling has been also conducted in Antarctic regions to elucidate interspecific differences in traits, species distributions, and genetic diversity.

(2) How do tardigrades reproduce?
Tardigrades employ both sexual and parthenogenetic reproduction. My study particularly focuses on species that reproduce sexually, aiming to clarify the mechanisms by which they produce offspring. By examining morphological differences in male sperm and female eggs, this research explores how these traits influence reproductive behavior, whether they can serve as taxonomic indicators, and how they contribute to reproductive isolation and species diversification.

(3) What is happening inside the body of tardigrades?
In many species of tardigrades, the chromosome number is fixed at five to six. Within this constraint, what factors drive species divergence? Furthermore, although sex chromosomes have not yet been identified, how do tardigrades determine sex? To address these questions, I will investigate these unresolved mysteries using approaches from molecular biology and genomics.