convergent evolution of
defensive integument
in mammals
Spines & Armor
^ Mesomys_hispidus
Pronounced defensive integument (body covering with heavy-duty defense capabilities) is widespread in some animal phyla, such as arthropods, and common in some classes of chordates, such as reptiles and ancestral fish, but is relatively uncommon in mammals.
Why has defensive integument evolved in some lineages but not in others? As with all adaptations, certain tradeoffs apply; various suites of adaptations work marvelously together while others flop. In this project, Joy is investigating a certain combination of adaptations that may be part of an "armored mammal syndrome". Methods include mathematically modeling in a 3-trophic level system and empirical analysis focusing on order Cingulata (armadillos) and family Echimyidae (spiny rats -- though they're not all spiny!).
In extant mammals we see:
1) plated armor : Philodota (pangolins) & Cingulata (armadillos)
2) spiny hairs/ quills : Tachyglossidae (echidnas), Tenrecidade (tenrecs), Erinaceidae (hedgehogs), Cricetidae (New World rats and mice), Muridae (Old World rats/ mice), Platacanthomyidae (Spiny dormice), Hystricidae (Old World porcupines), Erethizontidae (New World porcupines), & Echimyidae (spiny rats)
Wait, I've heard this before!
Researchers such as Lovegrove (2001), Stankowich (2012), and Stankowich & Campbell (2016) have offered concurrent hypotheses to explain cases of convergent evolution of defensive integument in mammals. It is probable that each of these hypotheses provides a piece to the larger puzzle.
Squirrels seem to be the unofficial mascots of many North American universities. Love them or hate them, they're often all over the place. However, of 40-something species of sciurids (tree squirrels, ground squirrels, chipmunks, flying squirrels, prairie dogs, and marmots) in the Canada and the US, only a small subset are campus-regulars and several species don't show up at all. We've reached out to professors and researchers at >500 colleges and universities in the US and Canada, asking which species of sciurids they have (and don't have) on their campuses. Analysis is in progress, and will address questions of range size and range expansion, species interactions (squirrel-squirrel and others), habitat, and historical changes.
sciurids on college/university campuses in Canada and the US
Campus Squirrels
^ Otospermophilus beecheyi
JOY
CONTACT
Joy is a grad student at the University of Illinois at Chicago, which locals call UIC. She's studies evolutionary theory because she finds it fascinating and is compelled by the concept of fundamental laws. She studies mammals because, frankly, she is really fond of them. Her research projects involve components of landscape ecology, stable isotope ecology, functional morphology, and theory -- specifically in regard to predator-prey dynamics.
Joy is grateful for the guidance, support, and enthusiasm of her academic advisor Joel Brown, as well as Chris Whelan and committee members Miquel Gonzalez-Mehler, Emily Minor, Pepe Iriarte-Diaz, and Bruce Patterson. She is particularly indebted to the training and inspiration provided by the individuals of The Field Museum's Mammals Department and Andes-Amazon team of the Keller Science Action Center, with whom she's had the pleasure of learning.
Joy is motivated by an interest in fundamental laws, sense of responsibility to the planet, fondness for animals, and earnest desire to do Bill Stanley proud.
Joy Peplinski
PhD Candidate, Brown Lab
University of Illinois at Chicago
jpepli2@uic.edu
Biological Sciences (MC 066)
845 W Taylor St
Chicago, IL 60607
^ Cavia porcellus
^^ in regard to everyone else...
please ask a lepidopterist
Foraging ecology of the porcupine Coendou prehensilis
in four mammalian communities
using stable isotope analysis
Research in the Works
Coendou prehensilis, known as the Brazilian porcupine or prehensile-tailed porcupine, is a charismatic species* whose range extends over half of South America, yet we know surprisingly little about its natural history. Why? Neotropical porcupines don't make it easy to be observed -- they are nocturnal, arboreal, usually solitary, and generally inconspicuous. Even the most diligent researchers on the ground (even while radio-tracking), would have a hard time observing porcupines' behavior while they quietly roam the canopy at night. Observational studies are indispensable, but this study aims to circumvent the aforementioned logistical issues by using already-collected museum specimens and stable isotope analysis (dC13 and dN15) to learn about the porcupines' diet and foraging behavior. C. prehensilis will be studied in the context of four mammalian communities, from four South American localities.
* charismatic designation based on consideration of incredible noses, tails, permanently surprised-looking eyes, quills, and videos of the species eating, vocalizing, and honestly just walking -- it's highly entertaining.
Questions:
1) What are the basic components of the diet of C. prehensilis?
2) At which canopy level does C. prehensilis typically forage? (Does it forage at all canopy levels equally?)
3) How do the foraging behaviors of C. prehensilis vary (or remain constant) in different areas of its distributional range, with varying mammal communities?