The Study Of Feedback Neuromodulation And Metabolic Changes Of Male Courtship In Drosophila

The survival pressure caused by environmental changes and the reproductive pressure caused by intraspecific competition lead to all animals in nature have to face the choice between survival and reproduction.Under the impetus of natural selection,animals have evolved two main reproductive strategies.The first one is called semelparity,in which the male mate as many females as they can in a single reproductive episode before death.The other called iteroparity,in which males,including humans,can balance sex and survival well based on external environment and their internal state.So that they can reproduce many times in their lives.There are two questions implicit in these two reproductive strategies.1.Does excessive sexual behavior reduce the lifespan of males? 2.How do interoparity animals protect themselves from excessive sexual behavior?We used Drosophila courtship behavior as a research model.To adress the first question,we paired wild-type males with different numbers of virgin females,and the results showed that as the number of females increases,the lifespan of males reduced accordingly.This result indicates that mating behavior does reduce the lifespan of males.To adress the second question,we constructed an overmating model by activating the fruitless neurons of male Drosophila.We found that during the activation of fruitless neurons,the expression of neuropeptide F(NPF)and glutamate decarboxylase 1(Gad1),a key enzyme of GABA synthesis,were up-regulated,and the expression of choline acetyltransferase(Ch AT),a key enzyme of acetylcholine synthesis,was down-regulated in the brain of males.We also found that after 4 hours activation of fruitless neurons,males background courtship behavior was inhibited,and NPF signal was involved in this inhibition process.In addition,in order to avoid the influence of the x factors caused by artificial activation,we tested the courtship of a single male to 10 females in a natural state.The results showed that the male with NPF signal knockdown showed higher courtship levels than the control group,and the NPF signal originated from 3 pairs of male-specific NPF neurons.In summary,we found that mating behavior can reduce the lifespan of males,and the nervous system can inhibit over-mating through feedback regulation,in which NPF,GABA,and Ach signals are involved.These findings provide a reference for us to understand the relationship between survival and reproduction.In order to fully understand the changes caused by mating,we further examined the metabolic changes induced by continuous sexual drive,continuous sexual arousal and natural mating.We found that the continuous sexual drive caused the block of the tricarboxylic acid cycle,which may lead to the death of male flies.In addition,the continuous sexual arousal caused shortened longevity and changes of 26 metabolites.The natural mating state caused changes in 25 metabolites.Interestingly,there is no common differential metabolite between the two groups,suggesting that continuous sexual arousal and natural mating may be completely different physiological processes.In this study,we discover the connection between sex and death using Drosophila,and identified the feedback inhibitory signal NPF of male courtship behavior and the functional NPF neurons.In addition,we also identified metabolites that are potentially relevant to mating behavior.This lays the groundwork for our understanding of sex and death.