The collapse of Glossina tachinoides populations, within a 27-month period of weekly sampling by means of unbaited biconical traps, in two peridomestic agroecosystems is described. Consistent removal of parous flies through trapping and low recruitment of young flies into the population, were largely responsible for unabated decline in the apparent density of both G. tachinoides populations. Reduction in the size of the resident pig population to below five pigs/week/agroecosystem triggered the collapse of both tsetse populations. Some ecological implications of these findings and their possible application in tsetse control are discussed.

A Glossina community inhabiting a peridomestic agroecosystem encircling Orie-Orba in the Nsukka area was investigated with unbaited biconical traps for species composition, population characteristics and trypanosome infections. Only Glossina tachinoides Westwood and G. palpalis (Robineau–Desvoidy) were encountered, the former comprising over 99% of all 2877 tsetse caught. G. tachinoldes occurred at a weekly mean apparent density of 8.41 ± 0.98/trap which fluctuated in a manner characterized by decrease in the wet season and increase in the dry season. Traps caught males and females in equal proportions during the wet season but during the dry season males outnumbered females in the monthly trap catches. During either season, the female samples comprised mostly old flies. Pregnancy rate was high during both seasons and abortion was the only reproductive abnormality manifested. The size of mature eggs in utero varied in a manner suggesting the occurrence of nutritional stress during both seasons. Approximately 5% of 347 G. tachuinoides examined for trypanosomes were infected with procyclic trypanosomes only.

These observations, which have formed the basis of further investigations now in progress, are discussed in the light of earlier studies at this location and elsewhere, and in the context of certain peculiarities of intensively cropped agroecosystems.