Investigation of habitat for cockroaches at the outdoor urban environment III : Night observation of cockroaches in city parks

Abstract

In order to grasp the habitation of cockroaches in city parks, observations were carried out from August 2000 through August 2001 in 52 parks in Minatoku, Tokyo. Cockroaches were checked at night, and species, the number of individuals, the discovery place, the species of trees on which cockroaches were found and their activity were recorded. Cockroaches were found at 24 (46%) in 52 parks. The species of cockroaches were the smoky brown cockroach, Periplaneta fuliginosa and Japanese cockroach, P. japonica. They were found on the ground and on big and old trees of 12 family 19 species in the parks. Smoky brown cockroaches inhabited ginkgo, zelkova, and cherry trees. Japanese cockroach inhabited chinquapin in big parks exceeding 6,000m², oak, zelkova, and hackberry trees. Many smoky brown cockroaches were seen from July through September. Japanese cockroaches were found all the year round. There were peaks of the number of larvae especially in April and November. Smoky brown cockroaches were seen eating the garbage, the excrement of birds, sap and cat food left in parks. Smoky brown cockroaches as well as Japanese cockroaches were seen to pass the winter in the city part of Tokyo. City warming may promote those smoky brown cockroach to live outdoors. Moreover, feeding cats and pigeons may increase the number of cockroaches in the parks.