Study Of The Effects Of Early Social Deprivation On Pups' Ultrasonic Vocalization And Parental Behavior In Midday Gerbil(Meriones Meridianus)

On account of imperfect movement,sensation and thermoregulation,pups always call their parents by emitting ultrasonic vocalizations(USVs)during early stage of ontogenesis.And the speed of individual development the and features of ultrasonic vocalizations are usually regarded as indicators of mating system of the species.For the purpose of increase the survival rate of offspring and ensure the inclusive fitness of themselves,plenty of animal species would provide considerable care for their pups,that is,parent investment.In mammals,females always invest more energy and time on caring offspring than males,however,whether males provide parental care and how much time and energy they invested in it are closely related to their reproductive strategies.In addition,the effects of early deprivation(ED)on brain development have been widely used for studies of ontogenesis,reproductive behavior,parental behavior and social behavior.So,the following questions can be raised: what is the level and pattern of parental behavior of midday gerbils in Minqin desert area? What are the features of ontogenesis and ultrasonic vocalizations of midday gerbil pups? What effects would be caused by ED on ontogenesis,ultrasonic vocalization and parental behavior? All these questions need to be answered.Here,we studied ontogenetic,ultrasonic vocalization and parental behavior in three different situations,to discuss the patterns of ontogenetic and parental behavior,and provide basic data for the mating system establishment and fertility control of midday gerbils in Minqin desert area.In this study,behavioral observe methods was used to record and analyze parental behaviors of midday gerbils;Development parameters such as change of body weight and dates of pelage appear and eye opining was recorded by real-time mode.Ultrasonic detector was used to record and analyze.The main results are as follows:1.Ontogenesis of midday gerbils during early life stage.Visible pelage of pups appeared after 8.13 days of age,eye opining after 15.13 days of age.Significant different between body weight of male and female pups began to appear at the postnatal day(PND)18,males are heavier than females.Thinking about it in terms of sexual selection,the mating system of midday gerbil may be polygamy or promiscuity.2.Features of USVs emitted by midday gerbil pups.At 2 days of age,midday gerbil pups' USVs could be detected for the first time,and call rate of USVs was maintained at the highest level from 6 to 15 days of age.The maximum rate is 145 calls/min,this number is significantly higher than polygamy rodent species but more closed to monogamy species.Call rate was significantly decreased after 15 daysof age.it is consistent with the ontogenesis,namely,the movement and thermoregulatory capacity of pups were enhanced gradually after their eyes opened,in consequence,the degree of dependence on parents was reduced and the USVs were less than before.3.Parental behavior of midday gerbils.There was no significant difference between dam and sire at PND 3,6,and 9;Dam displayed more huddling than sire at PND 12 and 18;To compared with sire,the duration of dam contact with pups was longer than at PND 15,but shorter at PND 21;There was no significant difference between LG and retrieve of the dam and that of the sire.These results suggest that midday gerbil have high level of paternal behavior,which reflects the ethological character of monogamy species.4.The effects of ED on USVs and ontogenesis of midday gerbil pups.After early deprivation,there was no significant difference between ED group and parent care(PC)group in body weight and dates of visible pelage appear and eye opining,but the call rate and duration of each pulse were significantly reduced by ED.For the dam part,the duration of ED group was longer than PC group at PND 15,but the frequency was less than PC group at PND 3 and 12;Dam of PC group spent more time on contacting with pups than ED group at PND 3 and 15;Compared with PC group,ED dam displayed more LG at PND 3 and 15 as well as more retrieve at PND 6 and 9.For the sire part,compared with PC group,ED sire displayed more retrieve at PND 3 and more huddling and LG at PND 18,but less huddling at PND 6 and LG at PND 15;In addition,there was no significant difference between PC and ED sire on the duration and frequency of contacting with pups.Compared with huddling and contact,licking and retrieve can better reflect the initiative of parental care.From the above,ED could decrease pups' calls,but increased the parental behavior of midday gerbils.Based on the above results,we found that the USVs and paternal behaviors of the midday gerbils in the laboratory showed the characteristics of monogamy,while the differences in body weight between males and females showed the characteristics of polygamy.USVs of pups were reduced after early deprivation,but the parental behavior was increased.In addition,although body weight was declined and developed slowly,maternal behavior was increased.Both of these two results indicate that midday gerbils have high level of parental behavior,which suggests that sound signals may not be the only thing that stimulates parental behavior.