Effects Of Odors,Territory Competition And Commons Competition On Foraging Behavior In Reed Voles

In nature,animals often choose to occupy areas which have rich resources as their territory to ensure survival and reproduction.However,the resources is rare for animal,leading to the habitats for survival is limited,and intraspecific individuals who have a high degree of similarity in the demand for resources,which makes the individuals often fiercely compete for the territory resources.Whether it is threatening sing,or competitive eviction,or a competitive approach such as physical contact,it will result in energy and resources loss.The foraging behavior of herbivorous small mammals is not only closely related to the feeding environment,food resources and predation risk in the environment,but also closely related to other individuals with competitive behavior.When the animal enters the foraging areas where there is occupant or there are odors of secretions such as urine and feces,what is the variation in the foraging behavior of both the squatter and the invader? and what is the effects on the intake rates? Fiercely compete in intraspecific individuals and intrespecific individuals,as well as the existence of predators often lead to frequent abdicate of the occupant in the wild habitats,then making areas become a commons for all individuals to compete.When intraspecific individuals are foraging in the commons at the same time,how will the foraging behavior of the individuals change,and will it cause a huge variation in the intake rate? The sequential process of foraging behavior and behavioral parameters of the reed voles(Microtus fortis)foraging in homogeneous food concentrated patches consisting of fresh leaves of crabgrass(Digitaria sanguinalis)were measured.To test the sequence and frequency of various types of behavioral actions and effect on ingestion rate are caused by compete in territory or commons.To reveal the evolutionary behavioral significance of the herbivorous small mammal whom reed vole(Microtus fortis)in compete for rare food resources and territory.Our results showed that,(1)the odors from themselves secretions such as urine and feces significantly shortened the foraging decision time and foraging interruption time of individuals,then dramatically increased their intake rates.But the odors from other intraspecifices secretions such as urine and feces significantly increased foraging decision time and foraging interruption time of individuals,due to their intake rates decreased.Analyses of the dynamic changes of parameters of vigilance behavior of reed vole showed that odors from themselves significantly reduce their the proportion of vigilance time for sniffing,but dramatically increased the proportion of vigilance time for scanning.In contrast,the odors from other individuals significantly increased the proportion of vigilance time for sniffing,scanning and listening in the individual.These results revealed that odors from themselves or other individuals could both triggered variation in parameters of foraging behavior,which change the foraging interruptiontime,resulting in dynamic change of intake rate.(2)When the reed voles have competition encounter in territory,the foraging decision time of occupant was significantly shortened,but the foraging decision time of intruder was dramatically lengthened.Despite the proportion of foraging interruption time of occupants and intruders both significantly increased,then caused the intake rates both dramatically decreased,foraging interruption time of occupants was significantly higher than intruders,due to the intake rates of occupants was significantly lower than intruders.Analyses of the dynamic changes of parameters of vigilance behavior of reed vole showed that compared to control individuals,occupants and intruders both significantly shorted proportion of vigilance time spent on scanning and dramatically increased the proportion of vigilance time spent on staring and listening,but the proportion of time of scanning and staring of intruders was significantly higher than occupants.The results demonstrated that competition in the territory which caused the variability in parameters of the vigilance behavior of occupants and intruders,proportion of foraging interruption time was increased and intake rate was decreased,however the proportion of time of scanning and staring of occupants was significantly lower than intruders,result in the proportion of foraging interruption time of occupants was significantly lower than intruders,then intake rates was dramatically higher intruders.These results revealed that occupant has a advantage when compete with intruders in their territory.(3)There are three levels of competition in commons,and foraging behavior is quite different in the three levels.compared to control females and males individuals,intake rates of females and males individuals of first level was significantly increased,but their intake rates significantly reduced in second level,while there was no significant change in the intake rates of males and females in the third level.Analyses of the foraging interruption time influencing intake rates showed that compared to control females and males individuals,in the first level,the proportion of foraging interruption time of females and males was significantly reduced,on the contrary,the proportion of foraging interruption time of females and males in the second level was significantly reduced,while the proportion of foraging interruption time of females and males in the third level was not significantly changed.Analyses of the dynamic changes of parameters of vigilance behavior causing individual interrupted foraging in foraging activities showed that in the three different levels of competition in the commons,reed voles spend on time of vigilance behavior was significantly different.The proportion of time of sniffing,upright scanning and listening of females and males individuals in first level significantly was lower than control females and males individuals,however,there was no significant difference in the proportion of vigilance time spent on scanning and staring between two groups.In second level,the proportion of time of sniffing,scanning,staring and listening of females and males individuals was significantly increased,butthere was no significant difference in the proportion of vigilance time spent on upright scanning between two groups.The difference is that there was no significant difference in the proportion of vigilance time spent on sniffing,scanning,upright scanning,staring and listening of females and males individuals between control groups and third level.These results revealed that the first level of commons competition,In order to temporarily obtain the maximum available resources and maximize fitness,individuals will spend more time on foraging,caused the foraging interruption time was reduced and the intake rates was increase;the second level,as individuals fight for food and space resources,they spend more time on vigilance,which leads to foraging interruption time was increased and their intake rates was decreased,results in the tragedy of commons;the third level,competition have a state of balance for the owners of the common area gradually established,so that the intake rates of occupant remained stable.