Biodiversity and population dynamics of litter-dwelling cockroaches inBelezma National Park (Algeria)

Abstract

This study aims to investigate the diversity, population dynamics, and distribution of forest cockroaches from the litter of three types of Mediterranean forests (Pinus halepensis, Juniperus phoenicea, Quercus ilex) in Belezma National Park (Northeast Algeria). In every type of forest, blattopteran individuals were hand-collected fortnightly from March 2013 to July 2014. Population dynamics were tested by multivariate analysis of variance for forest types and study months. The capture of 1885 individual forest cockroaches allowed the identification of six species (Loboptera angulata, Dziriblatta stenoptera, Phyllodromica subaptera, Phyllodromica zebra, Phyllodromica cincticollis, and Phyllodromica trivittata). In all studied forests, these species produced two generations per year (spring and autumn), in which the number of females was significantly higher than the number of males. However, P. cincticollis established a single generation in the spring with a balanced sex ratio. L. angulata and D. stenoptera were the most abundant species. The values of individual abundances, species richness, and biodiversity were higher in P. halepensis forest compared to Q. ilex and J. phoenicea.

An investigation of demographic and component Allee effects in the Madagascar hissing cockroach

“…As each population grew, the proportion of adult females also increased. This finding agrees with published reports of female-biased sex ratios in wild populations of several cockroach species (Azoui et al 2016). Although we do have modest evidence that adult males suffered greater rates of mortality than did adult females, perhaps because of the negative effects of male aggression (Clark and Moore 1994), we think it is unlikely that differential mortality during young age classes caused the skewed adult sex ratio.…”

“…We also asked if the initial population density affected long-term population dynamics. Lastly, we monitored changes in the adult sex ratio over time to determine if our experimental populations would exhibit the female-biased sex ratio of several cockroach species in the wild (Azoui et al 2016). Although sex ratio is not directly an Allee effect, a biased sex ratio can contribute to mate limitation, which is a possible mechanism for Allee effects (Kramer et al 2009).…”