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- Creators: School of Life Sciences
Description
We examined the evolutionary morphological responses of Drosophila melanogaster that had evolved at constant cold (16°), constant hot (25°C), and fluctuating (16° and 25°C). Flies that were exposed to the constant low mean temperature developed larger thorax, wing, and cell sizes than those exposed to constant high mean temperatures. Males and females both responded similarly to thermal treatments in average wing and cell size. The resulting cell area for a given wing size in thermal fluctuating populations remains unclear and remains a subject for future research.
ContributorsAdrian, Gregory John (Author) / Angilletta, Michael (Thesis director) / Harrison, Jon (Committee member) / Rusch, Travis (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Fruit flies show a strong attraction to fruit odors. Most fruit odors, including strawberry scent, are complex multimolecular mixtures comprised of many chemically distinct constituents. How animals are able to process these mixtures and derive behaviorally relevant information is largely unknown. A new procedure was created to test odor preference for Heisenberg canton-s strain of Drosophila melanogaster. 30 flies were cold anesthetized at 4.2°C for 30 minutes and then placed in a testing arena. After acclimating for 45 minutes, the flies were exposed to two sources of air, one with ripe strawberry odor and one with only humidified air. Images were captured every minute for an hour and a preference index was calculated for every 10th image. The Drosophila had a positive average preference for the strawberry odor. Five out of six trials showed a general increase in odor preference over the course of the trial. While there was a generally positive trend for average preference over time, there was not a significant increase in average odor preference from time 1 to time 60. The data indicates that Drosophila show a preference for strawberry odor over humidified air, and we propose to extend this test to investigate how Drosophila process and react to complex odors and their chemical constituents.
ContributorsSteinmetz, Kyle J (Author) / Smith, Brian (Thesis director) / Jernigan, Chris (Committee member) / School of Life Sciences (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Animals are thought to die at high temperatures because proteins and cell membranes lose their structural integrity. Alternatively, a newer hypothesis (the oxygen and capacity limitation of thermal tolerance, or OCLTT) states that death occurs because oxygen supply becomes limited at high temperatures. Consequently, animals exposed to hypoxia are more sensitive to heating than those exposed to normoxia or hyperoxia. We hypothesized that animals raised in hypoxia would acclimate to the low oxygen supply, thereby making them less sensitive to heating. Such acclimation would be expressed as greater heat tolerance and better flight performance in individuals raised at lower oxygen concentrations. We raised flies (Drosophila melanogaster) from eggs to adults under oxygen concentrations ranging from 10% to 31% and measured two aspects of thermal tolerance: 1) the time required for flies to lose motor function at 39.5°C at normoxia (21%), referred to as knock-down time, and 2) flight performance at 37°, 39°, or 41°C and 12%, 21%, or 31% oxygen. Contrary to our prediction, flies from all treatments had the same knock-down time. However, flight performance at hypoxia was greatest for flies raised in hypoxia, but flight performance at normoxia and hyperoxia was greatest for flies raised at hyperoxia. Thus, flight performance acclimated to oxygen supply during development, but heat tolerance did not. Our data does not support the OCLTT hypothesis, but instead supports the beneficial acclimation hypothesis, which proposes that acclimation improves the function of an organism during environmental change.
ContributorsShiehzadegan, Shayan (Co-author) / VadenBrooks, John (Co-author) / Le, Jackie (Co-author) / Smith, Colton (Co-author) / Shiehzadegan, Shima (Co-author) / Angilletta, Michael (Co-author, Thesis director) / VandenBrooks, John (Committee member) / Klok, C. J. (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05