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You searched for subject:(Inducible chemical defenses). Showing records 1 – 3 of 3 total matches.

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University of Delaware

1. Charpentier, Corie L. Fish kairomone-induced defenses in crustacean zooplankton: on the diversity of strategies, mechanism, and environment.

Degree: PhD, University of Delaware, School of Marine Science and Policy, 2017, University of Delaware

URL: http://udspace.udel.edu/handle/19716/21770 

Predator chemical cues, or kairomones, induce behavioral and morphological defense strategies in zooplankton. For example, several species become more responsive to light following exposure to fish kairomones. These behavioral changes likely impact diel vertical migration (DVM). A nearly universal behavior amongst zooplankton, DVM generally describes the nighttime ascent to feed and daytime descent to avoid visual predators. Although predator avoidance was proposed as the adaptive significance of DVM decades ago, we know little about the mechanism by which kairomones alter photobehavior. In addition, several zooplankton species exhibit kairomone-induced morphological defenses (e.g. spines), although previous reports of morphological plasticity have been generally limited to freshwater zooplankters. Despite laboratory and field evidence of kairomone-induced defenses, further work is needed to quantify the effective concentration of kairomone molecules in marine environments. ☐ Here, I first evaluated the mechanism by which kairomones enhance photoresponses in zooplankton. Comparing behavior and visual physiology (electrophysiology, eye structure), I found that kairomones altered photobehavior by increasing visual sensitivity at the photoreceptor level in the larvae of two marine crab species, Rhithropanopeus harrisii and Hemigrapsus sanguineus, as well as in a branchiopod crustacean, Artemia spp. Using similar behavioral experiments, I also found that signaling by a ubiquitous neurotransmitter, γ-aminobutyric acid (GABA), is required for detection and/or processing of predator kairomones in larval H. sanguineus. In addition, larvae lost the ability to detect kairomones after exposure to low pH/high CO2, over timescales that reflect diel/tidal pH cycles in coastal ecosystems (12 h). The mechanism of this pH effect differs from that described in fish, and the loss of kairomone-induced photosensitivity at low pH may be adaptive in these zooplankton under diel-cycling pH. ☐ In addition to behavioral defenses, crab larvae have spines. In some species, including R. harrisii, these spines are known to aid in predator defense. The freshwater crustacean zooplankton, Daphnia, exhibit drastic spine elongation after exposure to predator kairomones, but similar phenotypic plasticity has not been observed in estuarine or marine crustacean zooplankton. Here, I assessed the effect of developmental kairomone exposure on the morphology of crab larvae (R. harrisii and H. sanguineus). Kairomone exposure resulted in slightly elongated spines in larval R. harrisii as well as decreased consumption by a planktivorous fish, Menidia mendia, suggesting that the observed spine elongation is an inducible defense. ☐ The described behavioral and morphological defenses are induced by fish kairomones. In estuarine and marine systems, these signaling molecules are derived from body mucus and include sulfated glycosaminoglycans (sGAGs). Little work has been done to quantify these cues in marine environments or to assess whether kairomone concentrations… Advisors/Committee Members: Cohen, Jonathan H..

Subjects/Keywords: Biological sciences; Behavior; Brine shrimp; Chemical ecology; Crab larvae; Inducible defenses; Morphology

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Charpentier, C. L. (2017). Fish kairomone-induced defenses in crustacean zooplankton: on the diversity of strategies, mechanism, and environment. (Doctoral Dissertation). University of Delaware. Retrieved from http://udspace.udel.edu/handle/19716/21770

Chicago Manual of Style (16th Edition):

Charpentier, Corie L. “Fish kairomone-induced defenses in crustacean zooplankton: on the diversity of strategies, mechanism, and environment.” 2017. Doctoral Dissertation, University of Delaware. Accessed April 21, 2021. http://udspace.udel.edu/handle/19716/21770.

MLA Handbook (7th Edition):

Charpentier, Corie L. “Fish kairomone-induced defenses in crustacean zooplankton: on the diversity of strategies, mechanism, and environment.” 2017. Web. 21 Apr 2021.

Vancouver:

Charpentier CL. Fish kairomone-induced defenses in crustacean zooplankton: on the diversity of strategies, mechanism, and environment. [Internet] [Doctoral dissertation]. University of Delaware; 2017. [cited 2021 Apr 21]. Available from: http://udspace.udel.edu/handle/19716/21770.

Council of Science Editors:

Charpentier CL. Fish kairomone-induced defenses in crustacean zooplankton: on the diversity of strategies, mechanism, and environment. [Doctoral Dissertation]. University of Delaware; 2017. Available from: http://udspace.udel.edu/handle/19716/21770

2. Scherer, Avery E. Characterization of an induced morphological defense in the Eastern Oyster Crassostrea virginica.

Degree: 2018, Texas A&M University – Corpus Christi

URL: http://hdl.handle.net/1969.6/1170 

Subjects/Keywords: chemical ecology; inducible defenses; nonconsumptive predator effects; oyster reef; oysters; predator-prey ecology

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Scherer, A. E. (2018). Characterization of an induced morphological defense in the Eastern Oyster Crassostrea virginica. (Thesis). Texas A&M University – Corpus Christi. Retrieved from http://hdl.handle.net/1969.6/1170

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Scherer, Avery E. “Characterization of an induced morphological defense in the Eastern Oyster Crassostrea virginica.” 2018. Thesis, Texas A&M University – Corpus Christi. Accessed April 21, 2021. http://hdl.handle.net/1969.6/1170.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Scherer, Avery E. “Characterization of an induced morphological defense in the Eastern Oyster Crassostrea virginica.” 2018. Web. 21 Apr 2021.

Vancouver:

Scherer AE. Characterization of an induced morphological defense in the Eastern Oyster Crassostrea virginica. [Internet] [Thesis]. Texas A&M University – Corpus Christi; 2018. [cited 2021 Apr 21]. Available from: http://hdl.handle.net/1969.6/1170.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Scherer AE. Characterization of an induced morphological defense in the Eastern Oyster Crassostrea virginica. [Thesis]. Texas A&M University – Corpus Christi; 2018. Available from: http://hdl.handle.net/1969.6/1170

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Georgia Southern University

3. Sarmiento, Leslie Vanesa. Inducible Chemical Defenses in Temperate Reef Sponges of the South Atlantic Bight, U.S.A.

Degree: MSin Biology (M.S.), Department of Biology, 2008, Georgia Southern University

URL: https://digitalcommons.georgiasouthern.edu/etd/691 

Sessile organisms employing inducible defenses may receive protection from consumers while simultaneously minimizing the metabolic costs of maintaining these defenses. To investigate if reef sponges in the South Atlantic Bight employ inducible chemical defenses, I tested two predictions with Ircinia campana, I. felix, and Aplysina fulva. First, concentrations of antipredator compounds should covary with the abundance of sponge predators. Second, higher compound concentrations should be more effective at deterring predators. Secondary metabolite concentrations in two (I. campana and I. felix) of the sponge species showed temporal variation, which is consistent with the inducible defense hypothesis. Interestingly, higher concentrations of these compounds did not deter feeding by fish or urchins. In contrast, A. fulva, showed no significant temporal variation in the concentration of secondary metabolites, but had deterrent effects on fish predators even at low concentrations. Combined, these results do not support an antipredator strategy based on inducible chemical defenses. Advisors/Committee Members: Bruce A. Schulte, Risa A. Cohen.

Subjects/Keywords: ETD; Temperate reefs; Sponge; Inducible chemical defenses; South atlantic bight; Secondary metabolites; Postcolonialism in literature; Maori in literature; Jack N. Averitt College of Graduate Studies, Electronic Theses & Dissertations, ETDs, Student Research

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Sarmiento, L. V. (2008). Inducible Chemical Defenses in Temperate Reef Sponges of the South Atlantic Bight, U.S.A. (Masters Thesis). Georgia Southern University. Retrieved from https://digitalcommons.georgiasouthern.edu/etd/691

Chicago Manual of Style (16th Edition):

Sarmiento, Leslie Vanesa. “Inducible Chemical Defenses in Temperate Reef Sponges of the South Atlantic Bight, U.S.A.” 2008. Masters Thesis, Georgia Southern University. Accessed April 21, 2021. https://digitalcommons.georgiasouthern.edu/etd/691.

MLA Handbook (7th Edition):

Sarmiento, Leslie Vanesa. “Inducible Chemical Defenses in Temperate Reef Sponges of the South Atlantic Bight, U.S.A.” 2008. Web. 21 Apr 2021.

Vancouver:

Sarmiento LV. Inducible Chemical Defenses in Temperate Reef Sponges of the South Atlantic Bight, U.S.A. [Internet] [Masters thesis]. Georgia Southern University; 2008. [cited 2021 Apr 21]. Available from: https://digitalcommons.georgiasouthern.edu/etd/691.

Council of Science Editors:

Sarmiento LV. Inducible Chemical Defenses in Temperate Reef Sponges of the South Atlantic Bight, U.S.A. [Masters Thesis]. Georgia Southern University; 2008. Available from: https://digitalcommons.georgiasouthern.edu/etd/691

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