Biodiversity is increasingly under threat due to climate events. Studies examining the impact of climate change on biodiversity often tend to focus on understanding species survival. However, for persistence of species, equal focus requires on reproduction, a process is more vulnerable to heat stress than survival. This vulnerability arises from the susceptibility of gametes and gonads at sublethal temperatures, with sensitivity levels varying across different life stages. Despite this knowledge, majority of existing studies tend to focus on the effects of heatwaves on juvenile or adult stages or/and neglecting the cumulative impact across life stages and potential recovery dynamics. To Address this critical gap, we used Drosophila melanogaster as a model to explore (i) how does heat stress at different life stages affect male reproduction? (ii) how does life stage-specific heatstress affect males’ ability to recover? (iii) What are the mechanisms underlying the reproductive consequences of heat stress? Our findings reveal that gametes and gonads are highly susceptible to heat stress. Cummulative and presistence effect of heat stress can severely damage male reproductive fitness. Such effects could speed up population declines due to loss of fertility, highlighting the need to include effects on reproduction and their recovery in studies of biodiversity loss.