Retrospective mortality assessment of Glossina palpalis palpalis collections from Ijah-Gwari field station, Niger state Nigeria

Abstract

Handling and transportation of tsetse flies are fundamental for mortality assessment during fly collections. Previous works have indicated that tsetse fly mortalities increase with the rise in ambient temperatures. A seasonal mortality assessment of Glossina palpalis palpalis population collected from Ijah-Gwari field station was carried out based on the record as kept in the insectary of the Nigerian Institute for Trypanosomiasis Research, during the period between 2011- 2018; in order to determined fly mortality rates associated with handling and transportation of flies. Results indicated that whereas high percentage mortalities were recorded between 2016 (44%) and 2017 (57%); moderate mortalities were recorded in 2011 (36%), 2014 (29%), 2015 (19%) and 2018 (30%); while low mortalities of 10% were recorded in 2012 and 2013. Hot months of May (51%) and July (25%) gross mortalities contributed significantly to the increase in mortalities recorded in these years. The findings of this study show that extreme temperatures and relative humidity might be contributing factor of fly mortality. The handling and transport conditions might have sustained the high temperatures and humidity during transportation. Mean percentage mortality was observed to be higher in male (44%) than the female (33%) flies from Ijah-Gwari. The implication of this study as pertains salivary gland hypertrophy virus transmission is discussed.