Megan L. Porter

Lost along the way: the significance of evolution in reverse

Recently, researchers have begun to identify the prevalence of trait simplification, loss and reversal across all levels of biological organization. These studies have taken increasingly integrated approaches, incorporating phylogenetic, developmental and molecular methods, in the quest towards understanding the patterns and processes behind evolution in reverse. Here, we highlight the emerging interest in the reversibility of evolution by discussing a spectrum of studies examining both the genotypes and phenotypes of evolution in reverse. These integrative approaches have greatly increased our knowledge of the biological interactions that produce patterns of evolution in reverse and have led to promising new areas of research.

Methods for Analyzing Viral Evolution

Phylogenetic approaches are central to the study of plant virus evolution and coevolution with plant hosts. Phylogenetics is a field that is rapidly advanc- ing and spans the population/species boundary to include examining relationships among species as well as population dynamics and genetic associations within species. With a strong phylogenetic framework, a variety of exciting questions can be addressed relative to the evolutionary history of plant viruses. In this chapter, we outline the basic approaches for estimating phylogenetic or evolutionary histo- ries for a set of genetic sequences and then explore a variety of approaches to test hypotheses concerning viral population dynamics, selection pressures, recombina- tion, genetic diversity, and population growth.

Preliminary results from a survey of lava tube caves in the southwest region of the Ka’ū district of the Big Island, Hawai’i

The discovery of troglobionts in lava tube caves on the Hawaiian Islands archipelago altered our understanding of how species may evolve and permanently inhabit subterranean environments. To date, 74 troglobionts are reported from the islands with 44 known from the youngest (Big Island). Previous lava tube cave surveys on the Big Island have focused on the wetter, eastern side of the island and in lava tubes at higher elevations. Along with members of Cave Conservancy of Hawai’i, we surveyed 24 lava tube sections on the drier, western side of the Big Island, primarily in Hawaiian Ocean View Estates in the Ka’ū District. Surveys occurred during late November and early December of 2015–2017. Species present in each cave were documented by observation and limited collections of specimens for identification purposes. Significant species were discovered in these caves, representing new locations for rare and limited species previously documented from different regions on the island, and/or new, undescribed species from significant lineages that are federally listed on other islands. The most significant species observed included a reduviid thread-legged bug (Nesidiolestes sp.), a terrestrial amphipod (Spelaeorchestia sp.), a microvellid (Cavaticovelia sp.), and a new cave-adapted ‡ § | ¶