Showing 121 - 130 of 274 Items
Plant-mediated interactions within the milkweed insect community
Date: 2021-01-01
Creator: Katie J. Galletta
Access: Open access
- Induced defenses following herbivore damage can modify a plant’s chemical or physical characteristics and alter the plant’s interactions with subsequent herbivores. Common milkweed (Asclepias syriaca) provides an excellent system with which to study plant response-mediated interactions given its small but highly specialized herbivorous insect community and its ability to increase toxic cardenolide concentrations and latex production throughout its tissues upon attack. I conducted observational field surveys quantifying leaf damage to examine whether the indirect plant-mediated interactions amongst the milkweed herbivore community as demonstrated in other studies also occur in situ, as well as how foliar herbivory impacts insect flower visitation on A. syriaca. I found that four-eyed milkweed beetle (Tetraopes tetrophthalmus) damage had a negative effect on subsequent monarch (Danaus plexippus) larvae and swamp milkweed leaf beetle (Labidomera clivicollis) damage. I also found that monarchs laid more eggs on milkweed with no herbivore damage. Additionally, I observed a negative relationship between A. syriaca foliar herbivory and flower visitation, which has not been previously demonstrated but illustrates the various potential costs of herbivory to plant fitness. My work’s focus on observing the effects of natural herbivore damage offers insight as to how plant-mediated interactions operate among the milkweed insect community in situ. Furthermore, this study demonstrates how plant responses to herbivory in general can modulate ecological relationships between species that do not directly interact with each other.
To hum or not to hum: analyzing and provoking sound production in the American lobster (Homarus americanus)
Date: 2024-01-01
Creator: Renske Kerkhofs
Access: Open access
- American lobsters (Homarus americanus) produce humming sounds by vibrating their carapace. These sounds have a fundamental frequency on the order of 100 Hz, with multiple higher harmonics. Though I found no relationship between lobster carapace length and hum frequency, I observed sounds similarly structured to hums but with frequencies an order of magnitude higher, suggesting that lobsters may use a wider range of sounds than previously thought. Using laser vibrometry, I was able to pick up high frequencies of carapace vibration that were similar to those I observed on sound recordings. Lobsters seem to hum most readily when approached from above, but many studies have found it difficult to reliably find soniferous lobsters. To find a way to reliably evoke sound production in American lobsters without contributing to the sound environment, lobsters were exposed to overhead abstract visual stimuli on a screen, after which their behavioral reactions were recorded, as well as any sound production in response to the stimulus. Lobsters responded to the screen stimulus with the same types of behaviors with which they responded to general overhead physical stimuli. This study demonstrates that American lobsters may produce high-pitched sounds and that abstract visual cues can be used as a silent tool to elicit lobster behaviors, but not sound production.
Disease on the Half-Shell: Prevalence and impact of the protistan pathogen MSX on oyster population health throughout the Gulf of Maine Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2018-05-01
Creator: Madeline Schuldt
Access: Access restricted to the Bowdoin Community
Eelgrass meadow structure drives epifaunal community composition more than temperature during a Marine Heat Wave in the Gulf of Maine This record is embargoed.
- Embargo End Date: 2029-05-16
Date: 2024-01-01
Creator: Nicholas Takaki Tienhui Yoong
Access: Embargoed
Changes in chiropteran community structure associated with the white-nose syndrome epidemic: evidence for competitive release? Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2014-05-01
Creator: Adam Eichenwald
Access: Access restricted to the Bowdoin Community
Exploring Auditory Compensatory Neuroplasticity and Negative Phonotactic Behavior in G. bimaculatus Through Computer Vision and Machine Learning-Driven Analysis Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2025-01-01
Creator: Chongye "Tom" Han
Access: Access restricted to the Bowdoin Community
Introgression and adaptive gene flow in a Tropical Eastern Pacific parrotfish hybrid swarm This record is embargoed.
Date: 2025-01-01
Creator: Jolie R. Ganzell
Access: Permanent restriction
Forest regeneration and understory plant communities after introduced herbivore eradication on a boreal island Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2025-01-01
Creator: Mitchell F. Zell
Access: Access restricted to the Bowdoin Community
Monteverde: ecología y conservación de un bosque nuboso tropical
Date: 2014-12-01
Creator: Nathaniel T Wheelwright, Nalini M Nadkarni
Access: Open access
- La Reserva Biológica Bosque Nuboso Monteverde ha capturado la atención mundial de biólogos, conservacionistas y ecólogos y allí se han hecho vastas investigaciones durante los últimos 40 años. Unos 40.000 ecoturistas visitan el Bosque Nuboso cada año y se considera el bosque lluvioso arquetípico de las altitudes altas. Este libro, una traducción actualizada de "Monteverde: Ecology and Conservation of a Tropical Cloud Forest", editado por Nalini Nadkarni y Nathaniel T. Wheelwright (Oxford University Press, 2000) presenta capítulos sintéticos y recuentos específicos escritos por más de 100 biólogos y residentes locales. En un solo volumen documenta todo lo que se sabe en 2014 de la diversidad biológica de Monteverde, Costa Rica, y cómo protegerla. The Monteverde Cloud Forest Reserve has captured the worldwide attention of biologists, conservationists, and ecologists and has been the setting for extensive investigation over the past 40 years. Roughly 40,000 ecotourists visit the Cloud Forest each year, and it is often considered the archetypal high-altitude rain forest. This book, an updated and expanded version of "Monteverde: Ecology and Conservation of a Tropical Cloud Forest", edited by Nalini Nadkarni and Nathaniel T. Wheelwright (Oxford University Press, 2000), features synthetic chapters and specific accounts written by more than 100 biologists and local residents. The 862-page book includes 12 new short chapters and documents in a single volume everything known in 2014 about the biological diversity of Monteverde, Costa Rica, and how to protect it.
Hedgehog signaling is required at multiple stages of zebrafish tooth development
Date: 2010-12-02
Creator: William R. Jackman, James J. Yoo, David W. Stock
Access: Open access
- Background. The accessibility of the developing zebrafish pharyngeal dentition makes it an advantageous system in which to study many aspects of tooth development from early initiation to late morphogenesis. In mammals, hedgehog signaling is known to be essential for multiple stages of odontogenesis; however, potential roles for the pathway during initiation of tooth development or in later morphogenesis are incompletely understood. Results. We have identified mRNA expression of the hedgehog ligands shha and the receptors ptc1 and ptc2 during zebrafish pharyngeal tooth development. We looked for, but did not detect, tooth germ expression of the other known zebrafish hedgehog ligands shhb, dhh, ihha, or ihhb, suggesting that as in mammals, only Shh participates in zebrafish tooth development. Supporting this idea, we found that morphological and gene expression evidence of tooth initiation is eliminated in shha mutant embryos, and that morpholino antisense oligonucleotide knockdown of shha, but not shhb, function prevents mature tooth formation. Hedgehog pathway inhibition with the antagonist compound cyclopamine affected tooth formation at each stage in which we applied it: arresting development at early stages and disrupting mature tooth morphology when applied later. These results suggest that hedgehog signaling is required continuously during odontogenesis. In contrast, over-expression of shha had no effect on the developing dentition, possibly because shha is normally extensively expressed in the zebrafish pharyngeal region. Conclusion. We have identified previously unknown requirements for hedgehog signaling for early tooth initiation and later morphogenesis. The similarity of our results with data from mouse and other vertebrates suggests that despite gene duplication and changes in the location of where teeth form, the roles of hedgehog signaling in tooth development have been largely conserved during evolution. © 2010 Jackman et al; licensee BioMed Central Ltd.