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Full-Text Articles in Life Sciences
Biochemistry Of Trehalose Accumulation In The Spring Field Cricket, Gryllus Veletis, Alyssa R. Stephens
Biochemistry Of Trehalose Accumulation In The Spring Field Cricket, Gryllus Veletis, Alyssa R. Stephens
Electronic Thesis and Dissertation Repository
The freeze tolerant spring field cricket, Gryllus veletis, accumulates trehalose in the blood and tissues during cold acclimation. Trehalose is the main blood sugar in insects, thus its blood concentration is tightly regulated, and trehalose is readily metabolized. How do crickets modify their metabolism to accumulate trehalose in their hemolymph and tissues? I hypothesized that trehalose production, transport, and consumption were modified during the cold acclimation to facilitate trehalose accumulation. Trehalose and the trehalose-specific transporter, TRET-1, are distributed among all tissues, and trehalose accumulates in the hemolymph, fat body, Malpighian tubules, and gut. Trehalose production increases during cold acclimation …
Mechanisms Underlying Freeze Tolerance In The Spring Field Cricket, Gryllus Veletis, Jantina Toxopeus
Mechanisms Underlying Freeze Tolerance In The Spring Field Cricket, Gryllus Veletis, Jantina Toxopeus
Electronic Thesis and Dissertation Repository
Freeze tolerance has evolved repeatedly across insects, facilitating survival in low temperature environments. Internal ice formation poses several challenges, but the mechanisms that mitigate these challenges in freeze-tolerant insects are not well understood. To better understand how insects survive freezing, I describe a novel laboratory model, the spring field cricket Gryllus veletis (Orthoptera: Gryllidae). Following acclimation to six weeks of decreasing temperature and photoperiod (mimicking autumn), G. veletis juveniles becomes moderately freeze-tolerant, surviving freezing at -8 °C for up to one week, and surviving temperatures as low as -12 °C. Acclimation is associated with increased control of the temperature and …
Ionic And Osmotic Mechanisms Of Insect Chill-Coma And Chilling Injury, Heath A. Macmillan
Ionic And Osmotic Mechanisms Of Insect Chill-Coma And Chilling Injury, Heath A. Macmillan
Electronic Thesis and Dissertation Repository
A mechanistic understanding of how temperature limits insect performance is needed to accurately model insect distribution and abundance. Upon crossing the temperature of their critical thermal minimum (CTmin), insects enter a state of paralysis (chill-coma). Chill-susceptible insects accumulate injuries (termed chilling injury) during prolonged exposure to low temperatures. My objective was to determine the mechanisms by which both chill-coma and chilling injury manifest in chill-susceptible insects. In aquatic animals, critical thermal limits are associated with a temperature-induced failure of oxygen supply relative to demand (oxygen- and capacity- limitation of thermotolerance; OCLT), which leads to reliance on anaerobic metabolism …
The Sub-Lethal Effects Of Repeated Cold Exposure In Insects, Katie Elizabeth Marshall
The Sub-Lethal Effects Of Repeated Cold Exposure In Insects, Katie Elizabeth Marshall
Electronic Thesis and Dissertation Repository
While insect cold tolerance has been well studied, the vast majority of work has focused on the effects of a single cold exposure. However, many abiotic environmental stresses, including temperature, fluctuate within an organism's lifespan. In this thesis I address two major questions. First, does frequency of cold exposure impose additional stress on insects? Second, how does this stress translate to performance and fitness? I first summarize the literature on the effects of repeated cold exposure in insects, critically examining experimental designs. I then address my questions experimentally using four insect species with contrasting life histories and responses to cold …