The ca. 250,000 species of flowering plants around us display a vast diversity of floral forms. The fundamental questions I’m interested in are how differences in floral form produce different floral functions and how natural selection acts on floral function to produce the diversity of floral forms that we see.
My focus is on the Apocynaceae, the milkweed and dogbane family, a group of ca. 5000 species of flowering plants. Milkweeds (ca. 3000 of the 5000 Apocynaceae species) have evolved some of the most remarkable countermeasures to the unreliability of animal pollinators. The average pollen transfer efficiency (percentage of removed pollen grains deposited on conspecific stigmas) of milkweeds is greater than 10 percent while more typical animal-pollinated flowers with pollen dispersed in monads have an average pollen transfer efficiency of less than 1 percent). This extra-ordinary function is produced by some of the most structurally complex flowers in the world, comparable only to those of orchids. I’m using a diversity of approaches including pollination biology, evolutionary tree reconstruction, biogeography, climate niche analysis, and comparative development to understand where, when, how and why milkweeds got so efficient.
I’m also studying the evolution and species diversity of the genus Dischidia, a group of about 80 species from Southeast Asia that have evolved a symbiotic relationship with ants including some remarkable chemical and morphological modifications that function in this relationship. Species of Dischidia have ant-attractive seeds, inducing the ants to collect them, and some also modified leaves that function as ant houses.
As curator of the PH herbarium, one of my priorities is to develop databases that allow researchers to easily access information from herbarium specimens to track changes in plant distributions, flowering times and associations. These data are fundamental to helping us understand the unprecedented global change that we are experiencing today. As one of the oldest herbaria in North America, with specimens dating to the 18th century, the Academy’s collection represents a uniquely long record of plants over time. The information contained in these specimens is currently difficult to use since it is distributed among a million plus individual samples. Assembling this information into a database where it can be easily accessed and queried will help reveal how our environment has been changing over the past 300 years.
Tatyana Livshultz, PhD, is currently assistant curator of the Botanical Herbarium of the Academy of Natural Sciences of Drexel University. Before coming to the Academy in 2008, she was an assistant professor of biology at the University of Nebraska at Omaha and a post-doctoral fellow of the Arnold Arboretum of Harvard University. She has published 12 papers in peer reviewed scientific journals, is a member of the Collections Committee of the American Society for Plant Taxonomy and vice-president of the Philadelphia Botanical Club. Livshultz’s research focus on the evolution and pollination of the predominantly tropical milkweed family requires frequent fieldwork in the tropics and subtropics. Current projects are located in Taiwan, the Bahamas and Mississippi.