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Research

Current Research Projects

 

Production of ultra-black color in animals

Nanostructures in the scale of T. brookiana

Increasingly, animals like birds of paradise, jumping spiders, butterflies, and deep-sea fish have been shown to produce ultra-black color patches using micro- or nano-structures combined with an absorbing pigment like melanin. I am interested in characterizing the structures across taxa with scanning and transmission electron microscopy, then using Finite-Difference Time-Domain modeling to identify the components of the underlying structure that are essential for producing the incredible black color we see.

Phylogenetic distribution and function of ultra-black

I am working to describe the phylogenetic diversity of ultra-black in animals, particularly I am interested in whether there is convergence in the underlying nano-structures, or if animals are producing ultra-black with alternative mechanisms. Additionally, these patches could have different functions from enhancing signal contrast in sexually dimorphic birds and butterflies to camouflage from bioluminescent searchlights in deep-sea fish.

Deep-sea visual ecology

Micro-CT of a deep-sea hatchetfish

The deep sea provides unique optical challenges for organisms that are trying to remain hidden from predators and simultaneously find conspecifics to mate with. My work involves deep-sea camouflage in the form of bioluminescent counterillumination in the mesopelagic zone and ultra-black camouflage in bathypelagic fishes. In addition to camouflage, I have been working to understand signaling in the deep-sea. This has led me to investigate sexually dimorphic photophores and eyes in stomiid dragonfishes to understand how these fish with incredibly low biomass find suitable mates.

 

Undergraduate Research

 

Lift and drag on horseshoe crab shells

Simulated vorticity around a horseshoe crab carapace.

In the Miller Lab I used particle image velocimetry (PIV) and finite-element immersed boundary simulations (IBFE) to look at the lift and drag on horseshoe crab shells. Horseshoe crabs spend time in the surf zone where they are exposed to waves that can lift the shell off the substrate and cause the animal to flip over. Flipping leads to increased mortality in horseshoe crabs due to increased predation and difficulty righting. We found that horseshoe crab shells generate negative lift and minimal drag at relevant angles of attack, helping to maintain the orientation of the crab and prevent flipping.

Venus flytrap marginal spikes

Darwin hypothesized that the marginal spikes of the iconic venus flytrap are used to help retain larger prey while allowing small prey to escape through the spikes. In the Martin Lab we tested this hypothesis by removing the marginal spikes and testing prey capture performance of flytraps in a semi-natural experiment and in a laboratory experiment. We demonstrated that the marginal spikes greatly increase prey capture performance for moderate sized insect prey, but either have no effect or decrease the prey capture performance for larger insects. This has implications for understanding the role of morphological novelties in the evolution of carnivorous plant. Link the the paper here.