The Egg Stacking Strategy: Reproductive Plasticity in Response to Egg Parasitism in Mimosestes Amicus

Persistent Link:
http://hdl.handle.net/10150/293440
Title:
The Egg Stacking Strategy: Reproductive Plasticity in Response to Egg Parasitism in Mimosestes Amicus
Author:
Deas, Joseph Benjamin, Jr.
Issue Date:
2013
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
All organisms live in environments that are variable across space and time. Variation in selection across these environments may lead to the evolution of generalist genotypes that express phenotypic plasticity, in which one genotype can alter their phenotype (e.g., morphology, behavior, physiology) to match changes in environmental conditions, so that they may survive across a range of environments. In many egg-laying organisms that lack parental care, choosing an oviposition site is critical. The egg is an immobile stage of an animal's life cycle and mothers must balance a complex set of risks in deciding where to place their eggs. Because many biotic and abiotic factors are sources of selection on offspring survival, there is an advantage for females to evolve strategies in oviposition site selection to improve survival. This dissertation focuses on phenotypic plasticity in an offspring protection strategy that is triggered by natural enemies. In the seed beetle Mimosestes amicus (Coleoptera: Chrysomelidae: Bruchinae), females lay eggs on the outside of seed pods of legume trees and beetle larvae bore into and develop in the limited and discrete tissue of the seed. While most eggs are laid singly, I documented that beetle females superimpose eggs atop each other ("egg stacking") in response to the presence of egg parasitoids or parasitized eggs. In my first chapter, I investigated whether egg stacking is a strategy for protecting eggs from parasitism. In my second chapter, I examined female responses to variation in the number and dispersion of parasitized eggs on seed pods. Lastly, I investigated whether the intensity of stacking was affected by egg limitation (the risk of depleting her eggs before utilizing all hosts) or time limitation (losing reproductive ability or dying before laying all of her eggs). This study is unique in that it extends life history theory on egg and time costs to explain variation in egg protection behavior. The insights gained from this dissertation provide a foundation upon which we can examine how interactions among trophic levels impact the behavioral decisions made by insects that allow them to increase offspring survival.
Type:
text; Electronic Dissertation
Keywords:
Mimosestes amicus; offspring protection; phenotypic plasticity; seed beetles; Insect Science; Bruchinae
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Insect Science
Degree Grantor:
University of Arizona
Advisor:
Hunter, Martha S.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleThe Egg Stacking Strategy: Reproductive Plasticity in Response to Egg Parasitism in Mimosestes Amicusen_US
dc.creatorDeas, Joseph Benjamin, Jr.en_US
dc.contributor.authorDeas, Joseph Benjamin, Jr.en_US
dc.date.issued2013-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractAll organisms live in environments that are variable across space and time. Variation in selection across these environments may lead to the evolution of generalist genotypes that express phenotypic plasticity, in which one genotype can alter their phenotype (e.g., morphology, behavior, physiology) to match changes in environmental conditions, so that they may survive across a range of environments. In many egg-laying organisms that lack parental care, choosing an oviposition site is critical. The egg is an immobile stage of an animal's life cycle and mothers must balance a complex set of risks in deciding where to place their eggs. Because many biotic and abiotic factors are sources of selection on offspring survival, there is an advantage for females to evolve strategies in oviposition site selection to improve survival. This dissertation focuses on phenotypic plasticity in an offspring protection strategy that is triggered by natural enemies. In the seed beetle Mimosestes amicus (Coleoptera: Chrysomelidae: Bruchinae), females lay eggs on the outside of seed pods of legume trees and beetle larvae bore into and develop in the limited and discrete tissue of the seed. While most eggs are laid singly, I documented that beetle females superimpose eggs atop each other ("egg stacking") in response to the presence of egg parasitoids or parasitized eggs. In my first chapter, I investigated whether egg stacking is a strategy for protecting eggs from parasitism. In my second chapter, I examined female responses to variation in the number and dispersion of parasitized eggs on seed pods. Lastly, I investigated whether the intensity of stacking was affected by egg limitation (the risk of depleting her eggs before utilizing all hosts) or time limitation (losing reproductive ability or dying before laying all of her eggs). This study is unique in that it extends life history theory on egg and time costs to explain variation in egg protection behavior. The insights gained from this dissertation provide a foundation upon which we can examine how interactions among trophic levels impact the behavioral decisions made by insects that allow them to increase offspring survival.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectMimosestes amicusen_US
dc.subjectoffspring protectionen_US
dc.subjectphenotypic plasticityen_US
dc.subjectseed beetlesen_US
dc.subjectInsect Scienceen_US
dc.subjectBruchinaeen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineInsect Scienceen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorHunter, Martha S.en_US
dc.contributor.committeememberBronstein, Judith L.en_US
dc.contributor.committeememberDavidowitz, Goggyen_US
dc.contributor.committeememberPapaj, Daniel R.en_US
dc.contributor.committeememberHunter, Martha S.en_US
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