Temporal change of the aggregation response in Triatoma infestans

Adults and larvae of Triatoma infestans spend daylight hours assembled in s haded places. An assembling factor has been demonstrated in the excrement o f this species. We analysed different aspects of the dynamics of the respon se of bugs. Recently fed insects do not aggregate around faeces. They start to show a significant assembling response from the 8th hour after feeding onwards. Just deposited faeces do not evoke assembling, but a significant r ejection instead. This reaction switches 3 h after deposition, when the fae ces become attractive to the insects. The attractiveness of faeces persists for about 10 data and can be recovered after this time by rehydration. The se findings are discussed in relation to the biological role of faeces and the dynamics of the use of refuges by T. infestans.