Ongoing Research

Student research in the Crum Woods from Biology

Authors: Jillian Ma ’14, Olivia Edwards ‘14

Title: Conspicuousness and Batesian mimicry of the coral snake: effect of coral banding on caterpillar predation

Abstract: To solve the problem of predation, caterpillars display many adaptations including toxicity and Batesian mimicry of snakes. Toxic caterpillars often have high contrast, aposematic markings to warn predators of their toxicity. The larvae of two moths, an unidentified Bracca sp. and Pseudosphinx tetrio, are suspected of coral snake mimicry. Coral snakes have an infamous red, yellow, and black banding pattern that causes predator avoidance, even in novel predators. Knowing that conspicuous signals lead to avoidance, we tried to determine predators in the Crum Woods would avoid coral banded caterpillar models. Predators were expected to avoid coral banded models, but not a conspicuous green or cryptic brown control. Models were put on six transects in the Crum Woods for a period of four days in mid to late April. Height, orientation, and azimuth were randomized. Transect had a significant effect on predation rate, but model treatment did not. When results were separated by predator, model treatment had a significant effect on predation rate, with corals experiencing the highest volume of predation. This contrasts the results of previous studies, which might indicate that this lack of pattern avoidance is related to prey size.

Course: BIOL 131 (Animal Communication Seminar), Spring 2013, Professor Alex Baugh

Authors: Kelley Langhans ’16, Alejandro Bellon ’16, Taylor Tai ‘16

Title: Predation threat perception in the Carolina chickadee and tufted titmouse

Abstract: The Carolina chickadee (Poecile carolinensis) and tufted titmouse (Baeopholus bicolor) are small forest passerines that communicate information about predator presence to flockmates by producing broadband, easily-localized syllables called “D-notes” in their calls. Previous research has established that the number of D-notes produced depends on the type of predator and the potential threat posed, but a majority of studies have utilized predator stimuli from a single sensory mode in order to induce bird responses. Thus, the way that different modes of predator stimuli might contribute to the degree of risk perceived by chickadees and titmice is unknown. In this study we predicted that the addition of a visual hawk model to an acoustic hawk playback would increase the degree of risk perceived by chickadees and titmice. Furthermore, we aimed to determine whether such an increase in perceived threat would scale with the number of D-notes produced. The results suggest that multimodal stimuli may increase level of perceived predation threat, but that D-note production does not encode information about this difference.

Course: BIOL 131 (Animal Communication Seminar), Spring 2014, Professor Alex Baugh

Authors: Peter Nillson ’15, Patricia Zarate ’14, Elizabeth Cifuentes ‘15

Title: Factors influencing the syllable active space of European Starling (Sturnus vulgaris) song

Abstract: We investigated the active space of European starling (Sturnus vulgaris) song in three different habitat types (wooded, open meadow, and paved urban) over a 32 m transect under two noise conditions (ambient noise and traffic noise). Pre-recorded song was played back and recorded at various distances. Nine syllable types from the song were then separately analyzed and compared. Consistent with our predictions, attenuation was greatest in the wooded environment and least in the paved environment. We modeled the detection threshold curve for this species based on critical ratios from previous literature. The values generated from our model allowed us to determine the degree of syllable masking under the traffic noise condition. We found that syllables differed in the degree to which they were masked under the same conditions, with some syllables consistently being less masked. Contrary to our expectations, the model predicted that most syllables would be inaudible to starlings at distances of 2 meters. These results suggest that the critical ratio may not be a sufficient model for predicting syllable active space. Further research should test the validity of this model by using behavioral experiments on real receivers.

Course: BIOL 131 (Animal Communication Seminar), Spring 2014, Professor Alex Baugh