Behavior of German cockroach, Blattella germanica (L.), life stages as measured by computerized moving-image analysis
Abstract
Studies were conducted in the laboratory utilizing computerized moving-image analysis (MIA) to determine movement behavior between food, water and harborage resource sites and corresponding resource consumption rates for German cockroach, life stages. Nymphs (second and fifth instars), were examined for the entire nymphal stadium, which consisted of days having a 12:12 (L:D) photoperiod. Adults of different stages in the female reproductive cycle (non-mated females (NMF), mated non-gravid females (MNGF), and gravid females (GF)) and males were similarly examined. In addition, Markov chain analysis of the MIA data allowed determination of the foraging efficiency of second and fifth instars between the resource sites. The second and fifth instars exhibited a pattern of high foraging activity for the first half of the nymphal stadium, especially during each scotophase. For the last third of the stadium, the nymphs remained continuously in the harborage, moved very little and consumed little or no resources. This behavioral pattern indicated that the nymphal activity may be affected by hormones which regulate the molting cycle. Fifth instars were injected with ecdysone on the first d of the stadium, and movement and consumption were temporarily (1-2 d) depressed in the nymphs treated. A Markov chain analysis indicated both an age and sex difference in the foraging efficiency of nymphs. Female fifth instars became more efficient in their movements between the resource sites. The male fifth instars were very erratic in their movements and were not found to become more efficient over time. The second instars also did not improve their foraging efficiency. Adult behavior differences were evident between the female reproductive classes and males. The MNGF were the most active class overall, and consumed the most resources. The NMF were second to the MNGF in consumption and were less active. The GF were the most inactive, they spent the greatest time in the harborage and consumed few resources. The males were second to the MNGF for activity but consumed significantly less resources than both the MNGF and NMF. Implications of these findings related to the biology of these adult classes are discussed.
Degree
Ph.D.
Advisors
Bennett, Purdue University.
Subject Area
Entomology
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