Mortality of Anaea ryphea (Lepidoptera: Nymphalidae) immatures in Panama

Abstract

In order to assess the main mortality factors acting on immature stages of Anaea ryphea in Panama, I censused a population of this butterfly weekly from August 1991 to May 1992. A total of 515 eggs found on 129 marked food plants were individually numbered and followed through larval instars until death or disappearance. Results suggest that egg predation and rainfall are the main factors responsible for the low level of first instar recruitment. Egg parasitism rate was considered high for a tropical insect population, although it accounted little for overall mortality. A vertical life table constructed with data from one generation showed mortality was similar among larval instars, but was significantly higher for the eggs. No larval parasitism was observed, a finding perhaps related to low larval densities at the site.