Research

Our lab is new and developing, and our research will evolve as folks bring their unique perspectives and interests to the lab. Check back frequently for updates!

Planting native: a caterpillar’s perspective

While plants and their insect consumers can be found in ecosystems across the planet, not all plant food is equal. For example, an average oak tree contains thousands of herbivore individuals, and hundreds of species; in contrast, a neighboring maple might yield a dozen consumers from an even smaller handful of taxa. Simultaneously, not all insects are equally reliant on their host plants: while some consume many different kinds of plants (generalists), the majority are restricted to a small number of hosts (specialists). Together, this means that certain plants are disproportionately important to supporting not only high numbers of herbivores, but also particularly unique and irreplaceable insect faunas. Understanding the identity of such ‘keystone’ plant species in a given region or ecosystem can have major implications for conservation and management. In the arid West, where diverse shrubland ecosystems are a dominant vegetation type, such knowledge is lacking -- hampering our ability to understand and predict diversity outcomes in changing Western ecosystems, or make ecologically-informed decisions for restoration and management. Our lab will contribute to this gap by collecting and identifying butterfly and moth larvae (caterpillars) from several important vegetation types in Utah and the Intermountain West. We will use our database to identify ‘keystone’ native plants supportive of diverse and abundant insect communities.

Understanding trait-based drivers of food web structure

Over the past decade, ecologists have made great progress inferring function from the structure of interaction networks between species; for example, more compartmentalized (‘modular’) food webs are considered more stable than highly-connected ones. Thus, understanding the factors that shape network structure is an important tool to predict ecosystem-level consequences of global change. For plants at the base of terrestrial food webs, traits mediating resistance (or attraction) to herbivores are particularly critical. For example, nitrogen, water content of leaves, leaf toughness, leaf hairiness, and leaf chemistry are all traits which vary extensively within and among plant species, and are key drivers of herbivore interactions with host plants. Interestingly, these traits often vary in predictable fashion with the abiotic environment: plants in resource-poor environments – such as harsh soils, or arid climates – tend to be poorer in leaf nutrients and higher in leaf defenses, shaping smaller, less diverse, and distinctly-structured herbivore communities (Robinson and Strauss 2018, 2020). This linkage has far-reaching implications for restoration efforts, which often select plant species or populations tolerant of stressful conditions, and therefore more resilient to global change. We seek to understand how these choices affect build-up of food web interactions, and to identify plant populations that maximize multiple ecosystem functions - from drought tolerance to propagation of stable food webs. We are focusing on a widespread and ecologically foundational Western shrub for this work - Ericameria nauseosa. We are particularly excited to join forces with agency partners (USFS) for this work. Stay tuned!

Avoiding attack: evolution of caterpillar protective strategy

Caterpillars, like many herbivorous insects, are ‘in the middle’*: to survive, they must navigate an arsenal of defenses from plants — while also avoiding predation or parasitism from other organisms. This long evolutionary interplay has led to remarkable strategies to not only cope with, but often co-opt traits of plants for their own benefit. The most well-known examples are monarch butterflies, which store toxins from their milkweed hostplants in their own bodies, advertising their noxiousness with bright, conspicuous coloration. On the other end of the spectrum are caterpillars that capitalize on the textures and colors of the twigs and leaves they rest upon, evolving remarkably precise background-matching and mimicry. Still others add spines, hairs, or wiggly fleshy appendages. This morphological evolution is often accompanied by unique defensive behaviors, such as gregarious feeding; vomiting repellant regurgitant; or dropping quickly on a piece of silk. Our lab explores the factors that have favored evolution of this grand diversity of caterpillar protective strategy, and how the characteristics of host plants have played a key role (Robinson et al. 2023). This ongoing work would not be possible without the incredible endeavors of caterpillar aficionados David L. Wagner (UCONN) and Sam Jaffe (The Caterpillar Lab).

* Check out Bob Marquis and Suzanne Koptur’s new (2022) book by the same name.