Student Research Projects

The Relationship Between Leg Anatomy and Arboreal Behavior in Neotropical Harvestmen

Student Hannah Ring
Faculty Mentor(s)
Department Biology
Course BIO 489: Research in the Natural Sciences


In harvestmen, leg length, shape and armature may vary with ontogeny or between sexes. Leg morphology has also been observed to vary between species and has been used extensively in taxonomy to distinguish genera, subfamilies, families, and suborders. In the Gonyleptidae and temperate species of Sclerosomatidae, significant relationships between leg morphology and arboreal behavior have also been observed. In this study, we investigated the functional significance of leg morphology with respect to microhabitat selection for two different Neotropical assemblages. For each species examined in this study (n = 6), we used an image capturing system to measure scutal length and the length of legs I-IV (from the proximal surface of the trochanter to the distal tip of the tarsus). With the aid of a stereomicroscope, we also counted tarsal segments (tarsomeres) for legs I-IV for each specimen. For harvestmen from the Caribbean island of Trinidad, we compared relative leg length and the number of tarsomeres to climbing ability (as determined through a simple experiment). Taxa examined in this study included species from the families Cosmetidae, Cranaidae, Manaosbiidae, Sclerosomatidae, and Stygnidae. For harvestmen from La Selva, Costa Rica, we compared relative leg length and tarsomere numbers to field data regarding observations of vertical distributions and perch heights. Taxa examined in this study included species from the families Cosmetidae, Gonyleptidae, Sclerosomatidae and Zalmoxidae. Our results indicate that significant relationships exists between leg morphology (length as well as tarsomere number) and microhabitat selection for species occurring in each location.


Association of Southeastern Biologists, Birmingham, AL, April '09