Browsing Scientia Discipulorum vol. 6 (2013) by Publication date
Now showing items 1-4 of 4
Frequency of missing legs in the cave cricket, Hadenoecus subterraneusThe cave cricket (Hadenoecus subterraneus) is a keystone species in maintaining biological diversity in cave communities in Mammoth Cave National Park. Crickets must leave the cave to forage on nights when conditions are favorable, which puts them at considerable risk of predation. Invertebrates have developed defenses for predation, including autotomy (voluntary loss of a limb). We hypothesize that missing legs are a sign of predation pressure on the crickets, and may be vary in different environments. We used a visual census to record the sex-specific frequency of missing legs among adult cave crickets at eight different cave entrances. We expected males to be missing legs more than females because they must leave the cave refuge to forage more frequently than females; however, we found that males and females were missing legs in equal numbers. The hind leg was missing with greater frequency than other limbs, likely the result of cricket predator avoidance behavior (jumping), which puts the larger hind limb closest to the predator. The frequency of crickets with missing limbs varied among cave entrances from a low of 6.6% to a high of nearly 40%, with abundance varying yearly. In Frozen Niagara, which consistently had a high proportion of crickets missing legs, the percentage missing legs was highest in crickets roosting closer to the entrance (30.8%) than deeper (18.7%) into the cave. The goal of this survey was to study the pattern and implications of limb loss on foraging and predator avoidance.
An examination of sensory input in anti-predator behavior of the American crow (Corvus brachyrhynchos)Sensing, processing, and responding to environmental cues is a fundamental process, particularly for avifauna. The degree to which signals are effectively responded to, determines an individual's and a species' ability to function and flourish in its habitat. The sensing of sight and sound are highly evolved environmental analysis tools of the American crow (Corvus brachyrhynchos). This study examined how crows respond to visual and auditory cues in urban and rural environments. Taxidermic models of a great-horned owl (Bubo virginianus) and a red-shouldered hawk (Buteo lineatus), a recorded call of the great-horned owl, and a recorded crow mobbing call were used to test the mobbing response of local crows in several different locations. No significant difference was found in mobbing response between urban and rural environments. There was a significant difference in number of crows mobbing the two predator species. Results suggest that crows use sensory information differently; visual cues for predation avoidance and auditory cues for intraspecific communication. The results also suggest crows exhibit discretionary sensory processing and responses. This study provides insight to how a highly successful synanthropic species utilizes sensory information to thrive in natural and anthropogenic habitats.
Nearshore Fish Community Analysis On Northwestern Lake ChamplainCommunity surveys are necessary sources of information needed to properly manage fisheries. These surveys detail important historical data concerning past fish assemblages and the previous status of recreational game fish. Historically, Lake Champlain has received little attention with regard to fish community assemblage research. We undertook a beach, seine net survey at four locations along the northwestern shores of Lake Champlain. We surveyed several unique nearshore habitat types and recorded abiotic factors, fishes, and plant communities. Our results revealed 17 different taxa with four being non-native to the basin. Lakeview Park had the highest species richness and abundance, which we believe results from the presence of vegetation at the sampling site. The scope of our survey was limited (i.e., small species or young of the year game fish), thus we recommend future comprehensive surveys that include a variety of fish sampling methods.
A Revised Key to the Zooplankton of Lake ChamplainThis key was developed by undergraduate research students working on a project with NYDEC and the Lake Champlain Monitoring program to develop long-term data sets for Lake Champlain plankton. Funding for development of this key was provided by, the Lake Champlain Basin Program and the New York Department of Environmental Conservation (NYDEC). The key contains couplet keys for the major taxa in Cladocera and Copepoda and Rotifer plankton in Lake Champlain. Illustrations are by Erin Hayes-Pontius and Ian Ater. Many thanks to the employees of the Lake Champlain Research Institute for hours of excellent work in the field and in the lab: especially Casey Bingelli, Heather Bradley, Amanda Groves and Carrianne Pershyn.