• Vertebrate Paleontology
• History of the Earth
• Late Devonian fossil vertebrates
• Origin of tetrapods
• Fossil collecting
• Museum curation

• Taxonomy
• Systematics
• Entomology
• Biodiversity
• Water Quality
• Museum Collections

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.

Most of my research concerns the diversity and diversification of fishes. I seek to document and interpret the character (morphological and molecular) and taxonomic diversity of living and fossil fishes in the interrelated fields of systematics, faunistics and biogeography, and paleobiology. My work has a significant field component with exploration and collecting in poorly-known tropical freshwater habitats and regions.

• Molecular systematics
• Algae
• Evolution
• Taxonomy
• Algal ecology

• Thermal, hydric, & energetic effects on the activity and distribution of reptiles and amphibians
• Physical constraints on heat and mass exchange by reptiles and amphbians
• Physiological and physical constraints on gas exchange in sea turtle nests - effects on metabolism and development

• Brain plasticity and the evolution of brain structure
• Social behavior and division of labor, especially of eusocial Hymenoptera
• Thermal ecology and thermal physiology
• Network models of social group organization
• Behavior and ecology of bird-army ant interactions
• Human-safe insecticides

I am a taxon scientist who specializes on the the taxonomy and biogeography of Orthoptera (grasshoppers, crickets, katydids and their relatives), but I concentrate mainly on grasshoppers (Acridoidea) and crickets (Grylloidea). My principal interest, besides discovering new taxa, is in studying the origin of species.

Over my career I have worked mainly on large faunal treatments of crickets (crickets of Australia, Hawaii, the Caribbean, Fiji, and New Caledonia) and grasshoppers (North America and southern Africa). I have discovered and named approximately 1600 species and have discovered nearly 25% of the World’s 5000+ cricket species.

My main emphasis has been in studying the earliest stages of speciation. In crickets I use mainly the songs for initial recognition of species. This allowed me to discover large numbers of species that could not be distinguished by morphology alone.

I spent approximately 15 years assembling major online catalogs to the world’s species of Orthoptera, Mantodea, Phasmida and Blattodea. All told, the catalogs cover about 45,000 species. The databases are almost unique in biology in scope; they cover all known species and have begun to accumulate everything known about the world’s species (images, distribution, habitat, ecology, life cycles, etc). The Orthoptera Species File is now financially endowed and will be supported in perpetuity. No other taxonomic databases are as comprehensive.

I am currently attempting to complete two faunal treatments of grasshoppers: an all-species taxonomic treatment of North American grasshoppers, covering the entire continent (plus the Caribbean basin), plus an all-species treatment of the grasshoppers of Southern Africa (from the Zambezi southwards). Each volume will contain approximately 1000 species (of these about 20% of the species are expected to be new to science).

I spend much of my time working in museums that have good holdings of North American and southern African grasshoppers (Berlin, London, Madrid, Paris, University of Michigan, California Academy of Sciences, and the National Insect Collection in Pretoria).

• Water quality
• Algae, Protists
• Diatoms
• Aquatic Ecology
• Biological Collections
• Environmental Pollution

My research centers on the magnitude and origin of species-level diversity in the Mollusca. Estimates of the total number of living mollusk species range from less than 100,000 to more than 200,000, but that the actual number known is about 85,000. I use an informatics approach to better document the known diversity of mollusks and to estimate their total diversity. I developed Malacolog, an online database of Western Atlantic marine gastropods, and am an editor for the Mollusca in the World Register of Marine Species. I work in the Philippines, which has the world’s highest diversity of marine mollusks, in Jamaica, which has one of the most diverse faunas of terrestrial mollusks in the world, for which I developed an interactive key, and on the mollusks of Eastern Seaboard of the United States and Canada.

• Roles of bacterial symbionts in ant evolution
• Function, stability, and dynamics of heritable symbiont communities in aphids
• Genomic mechanisms driving correlations between symbiosis and insect ecology
• Coevolutionary histories between insects and their microbes

• Environmental policy and politics
• Urban planning
• Sustainability and resilience transitions
• Policy implementation
• Local knowledge and community science

• Ocean acidification
• Mollusks
• Climate change
• Paleobiology

• Volcano remote sensing and monitoring
• Volcanic gasses
• Igneous petrology and geochemistry
• Large Igneous Provinces

• Fate and transport of chemical contaminants
• Stable isotope and nutrient biogeochemistry
• Sediment geochemistry and deposition
• Water quality

• Urban Ecology
• Conservation Biology
• Pine Barrens Ecology
• Marine Ecology
• STEM Diversity & Inclusion
• International Education
• International STEM Mentorship

• Phylogenetics
• Host-parasite coevolution; Ornithology
• Systematic biology; Comparative biology
• Biodiversity surveys
• Genomics