Life History Correlates in Female Parasitoid Wasps: Exploring Old Concepts and New Frontiers

Persistent Link:
http://hdl.handle.net/10150/196036
Title:
Life History Correlates in Female Parasitoid Wasps: Exploring Old Concepts and New Frontiers
Author:
Asplen, Mark
Issue Date:
2007
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:
Although parasitoid wasps have shown promise as model systems for studying life history evolution, empirical studies of certain traits in these small insects have proven difficult. In this dissertation, two "black boxes" in the life histories of female parasitoids are examined: (1) oosorption, and (2) dispersal by flight.I first demonstrate that a short-lived species with high early reproductive investment (Eretmocerus eremicus) resorbs eggs, which runs counter to the notion that the time costs of oosorption are prohibitive to such wasps. Instead, it appears that the resorption mechanism in E. eremicus is capable of both decreasing costs and increasing nutritional benefits of oosorption relative to that of other parasitoid species. In addition, a literature review reveals four functional hypotheses for parasitoid oosorption: (1) age-related egg apoptosis, (2) conservation of ovarian capacity, and (3) nutrient allocation to either longevity or future oogenesis. As none of these can be rejected, I propose several avenues of future research: 1) refinement of physiological techniques to measure nutrient traffic into and out of eggs, 2) morphological phylogenetic studies of oosorption mechanisms, 3) development of lifetime nutrient budgets for parasitoids with different reproductive life histories, 4) examination of decay rates of oocytes with different yolk types, and 5) increased study of ovarian dynamics in pro-ovigenic parasitoids.Next, I describe results from a vertical flight chamber study designed to test hypotheses regarding the correlation between pre-oviposition dispersal and reproductive effort in parasitoid wasps. This experiment was conducted on 1-d-old female whitefly parasitoids from five species in two genera. The two Eretmocerus spp. showed a higher flight propensity than the three Encarsia spp. This may be, in part, due to a more time limited life history in the former. Within species, egg load did not correlate well with flight propensity for all species examined. Finally, among individuals of Er. eremicus, the relationship between effective flight distance and egg load appears to be context dependent, as data consistent with both positive and negative correlations were collected. Correlational changes between flight distance and egg load may be due to variation in biotic (female longevity) or abiotic (temperature, relative humidity) factors.
Type:
text; Electronic Dissertation
Keywords:
parasitoid; oosorption; dispersal; ovigeny; oogenesis
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Entomology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Byrne, David N.
Committee Chair:
Byrne, David N.

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleLife History Correlates in Female Parasitoid Wasps: Exploring Old Concepts and New Frontiersen_US
dc.creatorAsplen, Marken_US
dc.contributor.authorAsplen, Marken_US
dc.date.issued2007en_US
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.abstractAlthough parasitoid wasps have shown promise as model systems for studying life history evolution, empirical studies of certain traits in these small insects have proven difficult. In this dissertation, two "black boxes" in the life histories of female parasitoids are examined: (1) oosorption, and (2) dispersal by flight.I first demonstrate that a short-lived species with high early reproductive investment (Eretmocerus eremicus) resorbs eggs, which runs counter to the notion that the time costs of oosorption are prohibitive to such wasps. Instead, it appears that the resorption mechanism in E. eremicus is capable of both decreasing costs and increasing nutritional benefits of oosorption relative to that of other parasitoid species. In addition, a literature review reveals four functional hypotheses for parasitoid oosorption: (1) age-related egg apoptosis, (2) conservation of ovarian capacity, and (3) nutrient allocation to either longevity or future oogenesis. As none of these can be rejected, I propose several avenues of future research: 1) refinement of physiological techniques to measure nutrient traffic into and out of eggs, 2) morphological phylogenetic studies of oosorption mechanisms, 3) development of lifetime nutrient budgets for parasitoids with different reproductive life histories, 4) examination of decay rates of oocytes with different yolk types, and 5) increased study of ovarian dynamics in pro-ovigenic parasitoids.Next, I describe results from a vertical flight chamber study designed to test hypotheses regarding the correlation between pre-oviposition dispersal and reproductive effort in parasitoid wasps. This experiment was conducted on 1-d-old female whitefly parasitoids from five species in two genera. The two Eretmocerus spp. showed a higher flight propensity than the three Encarsia spp. This may be, in part, due to a more time limited life history in the former. Within species, egg load did not correlate well with flight propensity for all species examined. Finally, among individuals of Er. eremicus, the relationship between effective flight distance and egg load appears to be context dependent, as data consistent with both positive and negative correlations were collected. Correlational changes between flight distance and egg load may be due to variation in biotic (female longevity) or abiotic (temperature, relative humidity) factors.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectparasitoiden_US
dc.subjectoosorptionen_US
dc.subjectdispersalen_US
dc.subjectovigenyen_US
dc.subjectoogenesisen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineEntomologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorByrne, David N.en_US
dc.contributor.chairByrne, David N.en_US
dc.contributor.committeememberHunter, Martha S.en_US
dc.contributor.committeememberPapaj, Daniel R.en_US
dc.contributor.committeememberSmith, Robert L.en_US
dc.identifier.proquest2162en_US
dc.identifier.oclc659747267en_US
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