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Proc Natl Acad Sci U S A

Title:		An acoustic microscopy technique reveals hidden morphological defenses in Daphnia
Author(s):		Laforsch C; Ngwa W; Grill W; Tollrian R;
Address:		"Department of Biological Sciences, Institute of Environmental and Natural Sciences, Lancaster University, Lancaster LA1 4YQ, United Kingdom. c.laforsch@lancaster.ac.uk"
Journal Title:		Proc Natl Acad Sci U S A
Year:		2004
Volume:		20041101
Issue:		45
Page Number:		15911 - 15914
DOI:		10.1073/pnas.0404860101
ISSN/ISBN:		0027-8424 (Print) 1091-6490 (Electronic) 0027-8424 (Linking)
Abstract:		"Inducible defenses are common strategies for coping with the selective force of predation in heterogeneous environments. In recent years the conspicuous and often dramatic morphological plasticity of several waterflea species of the genus Daphnia have been found to be inducible defenses activated by chemical cues released by predators. However, the exact defensive mechanisms remained mysterious. Because even some minute morphological alterations proved to be protective against predatory invertebrates, it has been suggested that the visible morphological changes are only the tip of the iceberg of the entire protective mechanisms. Here we applied a method of ultrasonic microscopy with vector contrast at 1.2 GHz to probe hidden morphological defenses. We found that induction with predator kairomones increases the stability of the carapace in two Daphnia species up to 350%. This morphological plasticity provides a major advantage for the induced morphs during predation because predatory invertebrates need to crush or puncture the carapace of their prey to consume them. Our ultrastructural analyses revealed that the internal architecture of the carapace ensures maximal rigidity with minimal material investment. Our results uncover hidden morphological plasticity and suggest a reconsideration of former classification systems in defended and undefended genotypes in Daphnia and possibly in other prey organisms as well"
Keywords:		"Animals Biomechanical Phenomena Daphnia/*anatomy & histology/drug effects/*physiology Food Chain Microscopy, Acoustic/*methods Pheromones/pharmacology Predatory Behavior Species Specificity;"
Notes:		"MedlineLaforsch, Christian Ngwa, Wilfred Grill, Wolfgang Tollrian, Ralph eng Comparative Study 2004/11/03 Proc Natl Acad Sci U S A. 2004 Nov 9; 101(45):15911-4. doi: 10.1073/pnas.0404860101. Epub 2004 Nov 1"