The temporal occurrence of flesh flies (Diptera, Sarcophagidae) at carrion-baited traps in Grahamstown, South Africa

By

Villet, M. H. (Martin Herrer)
Clitheroe, Chrystal
Williams, Kirstin A.

Type

Article

Date of Publication

2017-1-18

Original Publication

African invertebrates : a journal of biodiversity research

Volume

58

Series / Issue

Issue: 1

Pages

1--8

Subjects

Forensic entomology , Population Dynamics , Sarcophagidae , seasonality , Weather

Contributed by

Pensoft Publishers

Language

English

Published by

Pietermaritzburg, South Africa Council of the Natal Museum 2001-

Identifiers

DOI: https://doi.org/10.3897/afrinvertebr.58.9537

 

Abstract

Eleven species of flesh fly were identified in a sample of 737 specimens captured during fortnightly trapping at three sites in Grahamstown, South Africa, over a year. Sarcophaga africa Wiedemann, 1824, S. inaequalis Austen, 1909, S. exuberans Pandellé, 1896 and S. tibialis Macquart, 1851 showed well-defined peaks between early October 2001 and late April 2002, and only S. africa was trapped at other times of year. These peaks occurred when average minimum and maximum ambient air temperatures were above 12°C and 22°C, respectively, and showed no obvious relationship to rainfall. There were indications of population cycles in all of these species. Sarcophaga hera Zumpt, 1972, S. arno Curran, 1934, S. inzi Curran, 1934, S. langi Curran, 1934, S. freyi Zumpt, 1953, S. nodosa Engel, 1925 and S. samia Curran, 1934 were too scarce to assess their patterns of occurrence rigorously. Insects attending a corpse are reputed to assist forensic entomologists in estimating the time of year when the body died. Some flesh flies provide more precise estimates than others, so several species should be used for cross-validation. Insect activity at a corpse depends on the weather, so that presence of a species indicates particular environmental conditions and not simply calendar dates (particularly if climate changes). Absence of a species is not necessarily evidence of specific conditions because species may not be present at all sites simultaneously, populations cycle even when their members are active, and low population densities may hamper detection of a species.