Kristin Hultgren

Smithsonian Marine Science Network Postdoctoral Fellow
National Museum of Natural History
Smithsonian Institution
MRC 163, P.O. Box 37012
Washington, DC 20013-7012

Synalpheus carpenteri, one of many Caribbean sponge-dwelling snapping shrimp in the gamberalloides group. Synalpheus shrimps have an enlarged major chela used for fighting, and sponge-dwelling species have a streamlined body shape well-suited to life in sponge canals (Photo credit: Tripp Macdonald)

Sponge-dwelling Synalpheus live in the excurrent canals of sponges like Lissodendoryx columbiensis, pictured here sliced open to show the network of canals.
I am broadly interested in integrating ecological and evolutionary methods to studying ecological and behavioral diversity in marine invertebrates. I rely on multiple approaches - ecological field studies, behavioral assays, and phylogenetic methods - to study the evolution of adaptive traits and how these traits influence coexistence and diversity in marine communities at multiple scales.

My current research focuses on how closely related species successfully coexist in similar habitats. I study this question and others in the Caribbean shrimp group Synalpheus, a diverse group of 40+ sponge-dwelling shrimp species that live in the interior canals of sponges in coral reefs. These closely related shrimps compete strongly for unoccupied sponge hosts in the field, and have strong morphological adaptations to their host sponges. I am investigating how phylogenetic relatedness and morphological similarity interact to influence coexistence of Synalpheus species in sponge hosts. In collaboration with Dr. Emmett Duffy, I am conducting a multi-site biogeographic study characterizing distribution, host use, and morphology of Synalpheus across the Caribbean. This work is funded by the Smithsonian Marine Science Network and by a National Geographic Research and Exploration Grant.

Although majoids are well-known for decoration camouflage, some species (such as Pugettia producta pictured above) rely instead on color camouflage
My dissertation research explored the evolutionary ecology of defensive traits in the brachyuran crab superfamily Majoidea. Majoid crabs, commonly known as "decorator crabs," are perhaps most well known for their characteristic "decoration" camouflage, in which they attach materials from their environment to hooked setae on their carapace. However, certain species decorate little and instead sequester pigments from algae for color camouflage. This variation in camouflage strategies among closely related species makes majoids an ideal group in which to examine the ecology and evolution of camouflage in marine invertebrates. For example, closely related species that live in nearshore algal environments use alternate forms of camouflage (color change or decoration) that provide equivalent protection against predators. In one species, Pugettia producta, the effectiveness of color camouflage also depends on behavioral processes such as color-dependent habitat selection. To examine broad trends in the evolution of camouflage in this group, I constructed the first molecular phylogeny of the superfamily Majoidea and used independent contrasts to examine how decoration behavior is correlated with other morphological traits such as body size.

Hultgren, K.M., and J. J. Stachowicz. Molecular phylogeny of the brachyuran crab superfamily Majoidea indicates close congruence with trees based on larval morphology. Molecular Phylogenetics and Evolution (in press)

Hultgren, K.M., and J. J. Stachowicz. 2008. Alternative camouflage strategies mediate predation risk among closely related co-occurring kelp crabs. Oecologia 55: 519-528. [pdf]

Hultgren, K.M., P.D. Thanh, and M. Sato. 2006. Geographic Variation in Decoration selectivity of Micippa platipes and Tiarinia cornigera in Japan. Marine Ecology Progress Series 326: 235-244. [link]

Byrnes J.E., J.J. Stachowicz, K.M. Hultgren, A.R. Hughes, S.V. Olyarnik, and C.S. Thornber. 2006. Predator diversity strengthens trophic cascades in kelp forests by modifying herbivore behavior. Ecology Letters 9:61-71. [pdf]

Harley, C.D.G., A. R. Hughes, K. Hultgren, B.G. Miner, C. J. B. Sorte, C.S. Thornber, L. F. Rodriguez, L. Tomanek, and S. L. Williams. 2006. The impacts of climate change in coastal marine systems. Ecology Letters 9:228-241. [link]