Abstract:
Aneuretus simoni, a species Critically Endangered globally and Endangered locally, is
the sole extant species of the family. It forms nests in substrates on the forest floor. In 2014, it was
discovered in the Meethirigala Forest Reserve in Gampaha District and a survey on its
presence, percentage nest abundance and mean nest density in three localities revealed that A. simoni
was a dominant, resident species with the mean nest density ranging from 0.2 to 0.8 m-2 at 57 m elevation
of the forest. The occurrence and nest density of the species were reassessed in the Forest
Reserve, nine years after its initial discovery, on 22 September, 2023, in a locality at 57
m elevation, using two standard methods. Twenty-five, honey baits were placed at 4 m
intervals along a 100 m transect, checked each bait after one hour using a field
microscope, and A. simoni workers were identified. Also, ants crawling on the ground,
in the soil, and beneath leaf litter were collected using a wet paint brush, and identified.
Worker ants of the species were observed by both methods. On February 10, 2024, the
nest density of A. simoni was investigated by laying 20 quadrats within each of two 100
m2 plots at the same elevation. Number of A. simoni nests within each quadrat was
counted, and the nest density of the species was calculated. The mean nest density
observed in this study, 0.4 nests m⁻², falls within the range of nest densities recorded in
the region in 2014. Rain prevailed during both surveys, with 27 - 29 °C air temperatures.
Nest density of present study indicated that A. simoni is still a resident species with a
continuous survival in the surveyed region.
