Research interests:
Leg autotomy and regeneration:
Autotomy (self amputation) of appendages in order to avoid predation is common to many animal groups. Several animals that can autotomize appendages can also later regenerate. However, autotomy and regeneration may lead to functional and energetic costs. My M.S. research at University of Cincinnati and some of my Ph.D. research here at Miami has focused on the costs and benefits of leg autotomy and regeneration in wolf spiders.
M.S. research at University of Cincinnati under George Uetz:
This research had both behavioral and developmental components. Results showed that the wolf spiders, Schizocosa ocreata, had reduced size increases or longer development times when regenerating a leg in the lab. Furthermore field caught spiders with missing or regenerating legs had lower body condition than intact spiders. Finally in laboratory experiments spiders missing or regenerating legs showed reduced foraging, but only when placed in a complex habitat.
Ph.D research at Miami University under Ann Rypstra:
In fall 2005 I conducted this study to determine the effects of leg regeneration and feeding regime on growth and development time. Spiders were placed in one of four treatments: 1) Well fed, intact, 2) Well fed, autotomy, 3) Low fed, intact, 4) Low fed, autotomy. Spiders were measured after molting to determine growth (ie. change in size and weight), and developmental increment was recorded. Results showed that regeneration had no effect on mass, but well fed spiders weighed significantly more than deprived spiders. Leg regeneration significantly reduced molt interval, while low feeding conditions significantly prolonged it. Cephalothorax width was largest in the well fed, intact group with no difference between the other three groups. Thus, impacts of regeneration on growth and development time in spiders may be partially determined by level of nutrition.
I also conducted a joint research project in fall 2005 with an undergraduate, Jason Madachy. We tested the effects of leg autotomy (yes/no), habitat complexity (straw/dirt), and predator cues (Hogna helluo silk present/absent) on foraging success and body condition in juveniles of the wolf spider Pardosa milvina using a fully crossed design. Our results showed that the number of crickets captured by P. milvina decreased in the complex habitat, but spider weight and abdomen width was unaffected. Conversely, predator cues had no effect on number of crickets captured, but spiders gained substantially less weight in the presence of cues. Autotomy had no effect on any measure of foraging success and furthermore there were no interactions between any of the factors tested. These results match those of previous studies for each independent factor. Although no interactions were significant between the factors in the lab, further studies should be conducted to determine whether these interactions may be more important under field conditions.
Colonization, competition and habitat selection:
My additional research interests involve how and why spiders move between habitats. P. milvina is a species that is found prevalently in agricultural fields in SW Ohio. This species is able to reach high numbers in the disturbed agricultural areas where much lower densities of other species are found. Therefore, P. milvina may have potential as a bio-control species. I am currently pitfall trapping in different habitats (Riparian, Woods, Old field, Corn field, Soy field) to determine where P. milvina occur, and whether or not they are habitat generalists. I am also doing a study with another Ph.D. student, Jason Schmidt, to determine what factors such as prey density and conspecific density may affect emigration of P. milvina.. Knowing more about where this species occurs and how it moves between natural and agricultural areas will help us to answer basic ecological questions about colonization vs. competitive abilities while gaining knowledge that may aid in biological control activities.
Academic training:
B.S. Berry College, 2002
M.S. University of Cincinnati, 2005
Contact information:
Email: wrinnkm@muohio.edu
Office: Pearson 165
Office phone: 513-529-1614