Territoriality in the flesh fly, Sarcophaga crassipalpis (Diptera: Sarcophagidae) was studied in the laboratory. In rectangular enclosures, male flies exhibited a lower tolerance (occupation of the same physical space) of same-sex conspecifics than did female flies. In circular arenas, male flies showed significantly higher levels of spatial separation among themselves (as determined from nearest neighbor analyses) than did females: males were distributed uniformly whereas females were nearly random. The male spatial behavior occurred during the photophase but not the scotophase of light-dark cycles, suggesting that visual cues are required for maintenance of inter-individual spacing. No significant differences in male spacing behavior occurred between subjective day and subjective night in either constant dark or constant light conditions, suggesting that spatial patterning is not driven by a circadian rhythm.

We have examined potential influences of gender, age, and nutrition on the expression of circadian locomotor activity rhythms in the flesh fly Sarcophaga crassipalpis. We found no significant differences in endogenous circadian period under constant dark conditions resulting from gender, nutrition, or age. Male and female flesh flies were predominantly diurnal under light-dark cycles, but their entrainment patterns differed. Females displayed higher activity levels and increasing activity with age, unlike males. Moreover, females exhibited an extraordinary, but transient, departure from diurnality which we characterize as “extended dark activity” (EDA), a continuous bout of locomotor activity extending three hours, or longer, into the dark phase at twice the median of the individual’s overall locomotor activity. EDA occurred as an age-dependent response to liver consumption. Our results suggest a linkage between physiological events associated with egg provisioning and locomotor activity as well as multiple influences on the expression of circadian clock-regulated behavior.

This thesis looks at the problem of developmental respiration in Sarcophaga crassipalpis Macquart from the biological and instrumental points of view and adapts mathematical and statistical tools in order to analyze the data gathered. The biological motivation and current state of research is given as well as instrumental considerations and problems in the measurement of carbon dioxide production. A wide set of mathematical and statistical tools are used to analyze the time series produced in the laboratory. The objective is to assemble a methodology for the production and analysis of data that can be used in further developmental respiration research.

1

Circadian rhythms dictate the timing of both once-in-a-lifetime adult emergence (eclosion) and daily locomotor activity rhythms in the flesh fly S. crassipalpis. Light cycles are considered the primary environmental time cue (zeitgeber), but the life history of S. crassipalpis suggests that temperature cycles (thermocycles) may also play a key role. This work evaluates the efficacy of thermocycling as a zeitgeber in S. crassipalpis. We found that shifting both light and temperature cycles of sufficient amplitude affect the phasing of eclosion and locomotor activity, but result in different patterns. Additional experiments suggest greater thermocycle sensitivity during the late metamorphic period and that thermocycling reduces variance in eclosion times. Taken together, these findings suggest that temperature cycles can be used by S. crassipalpis to time eclosion and adult locomotor activity, and that S. crassipalpis may be physiologically primed to use thermocycle information during metamorphosis.