Population biology and ecology and of Periplaneta americana (L.) in the urban environment
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The American cockroach, Periplaneta americana (L.), is an important urban pest due to its ability to invade residential and commercial structures from non-residential reservoirs. Extensive field studies were conducted in a large urban apartment complex, Lincoln Terrace (LT), managed by the Roanoke Redevelopment and Housing Authority (RRHA), in Roanoke, Virginia. Inspection in the RRHA-LT complex corroborated well with other researchers' finding that sewer and stornl drainage systems are the principal reservoirs for P. americana population in the temperate urban environn1ent. Investigations provided new evidence that basements of the RRHA-LT apartment buildings served as secondary reservoirs for this pest species. Environrnental and ecological parameters that characterize basements as important P. americana population reservoir foci were studied. Understanding how populations function in the urban environment is as important as identifying P. americana population reservoirs. Over two-years of fleld investigations demonstrated that foraging activity of P. americana was seasonal. A study of a simulated population of caged American cockroaches maintained in a basement environment confirmed that their foraging activity was seasonal. Foraging seasonality characterizes the seasonal pest status of this cockroach species in the temperate urban environment. Therefore, seasonally oriented control or management strategies for this pest species are proposed and discussed. Lipids, carbohydrates, and proteins of American cockroach adults were analyzed and quantified on a monthly basis for a year. Seasonal foraging activity was reflected by seasonal changes of metabolic reserves in this species. Low foraging a.;:;tivity in the colder, winter months characterized an overwintering period of P. americana populations in the urban environment. Lipids were the principal metabolic reserve for overwintering cockroaches, and accounted for a 22% of dry body weight loss in females and 18% in males. Proteins accounted for approximately 10% of the dry body weight loss for overwintering females and males. Glycogen concentration per unit dry weight increased 11 % to 15% during the overwintering period. This change suggests that glycogen may function as a cold hardiness substance rather than as a energy reserve during overwintering. Nutrient deficits of post-overwintering individuals in the population explained the underlying physiological driving force for significantly ir~creased foraging activities in the spring. Caged P. americana demonstrated a high reproductive potentia] in the basement environment. High reproductive rate created protein and lipid deficits in adults that required increased foraging for food and increased cannibalism of oothl!cae and young nymphs. Approximately 33% of the oothecae and 28% of nymphs were cannibalized in the caged population.
- Doctoral Dissertations