{"title":"小型哺乳动物摄影巢箱的研制及其在冲绳棘鼠繁殖计划估算中的应用","authors":"Nobuhiko Kotaka, M. Yasuda, Takuya Shimada","doi":"10.3106/ms2021-0025","DOIUrl":null,"url":null,"abstract":"Abstract. To estimate the reproductive schedule of the Okinawa spiny rat on the basis of its body size distribution, we developed a nest box with an auto-trigger camera. Three camera-installed nest boxes were used in the field in the northern part of Okinawa Island beginning in September 2015. The distance between eyes, an index of body size, was measured in 850 images of spiny rats. The reproductive schedule was estimated based on the emergence period of subadults. With the emergence of subadults, the distribution of body size index becomes a mixture of two normal distributions consisting of adults and subadults, so a Gaussian mixture model was employed to identify each distribution. The Gaussian mixture model revealed that the distribution of the estimated distance between eyes could be divided into two clusters, with a mixing ratio of 0.11 for Group 1 (subadult) and 0.89 for Group 2 (adult). Most individuals belonging to Group 1 appeared during the winter months of December to March, indicating that subadults were weaned primarily during this season. Consequently, reproduction of the Okinawa spiny rat is thought to be limited in autumn and winter.","PeriodicalId":49891,"journal":{"name":"Mammal Study","volume":null,"pages":null},"PeriodicalIF":0.8000,"publicationDate":"2021-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Development of a Camera-Installed Nest Box for Small Mammals and Its Application in Reproductive Schedule Estimation for the Okinawa Spiny Rat\",\"authors\":\"Nobuhiko Kotaka, M. Yasuda, Takuya Shimada\",\"doi\":\"10.3106/ms2021-0025\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Abstract. To estimate the reproductive schedule of the Okinawa spiny rat on the basis of its body size distribution, we developed a nest box with an auto-trigger camera. Three camera-installed nest boxes were used in the field in the northern part of Okinawa Island beginning in September 2015. The distance between eyes, an index of body size, was measured in 850 images of spiny rats. The reproductive schedule was estimated based on the emergence period of subadults. With the emergence of subadults, the distribution of body size index becomes a mixture of two normal distributions consisting of adults and subadults, so a Gaussian mixture model was employed to identify each distribution. The Gaussian mixture model revealed that the distribution of the estimated distance between eyes could be divided into two clusters, with a mixing ratio of 0.11 for Group 1 (subadult) and 0.89 for Group 2 (adult). Most individuals belonging to Group 1 appeared during the winter months of December to March, indicating that subadults were weaned primarily during this season. Consequently, reproduction of the Okinawa spiny rat is thought to be limited in autumn and winter.\",\"PeriodicalId\":49891,\"journal\":{\"name\":\"Mammal Study\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.8000,\"publicationDate\":\"2021-12-27\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Mammal Study\",\"FirstCategoryId\":\"99\",\"ListUrlMain\":\"https://doi.org/10.3106/ms2021-0025\",\"RegionNum\":4,\"RegionCategory\":\"生物学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"ZOOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Mammal Study","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.3106/ms2021-0025","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ZOOLOGY","Score":null,"Total":0}
Development of a Camera-Installed Nest Box for Small Mammals and Its Application in Reproductive Schedule Estimation for the Okinawa Spiny Rat
Abstract. To estimate the reproductive schedule of the Okinawa spiny rat on the basis of its body size distribution, we developed a nest box with an auto-trigger camera. Three camera-installed nest boxes were used in the field in the northern part of Okinawa Island beginning in September 2015. The distance between eyes, an index of body size, was measured in 850 images of spiny rats. The reproductive schedule was estimated based on the emergence period of subadults. With the emergence of subadults, the distribution of body size index becomes a mixture of two normal distributions consisting of adults and subadults, so a Gaussian mixture model was employed to identify each distribution. The Gaussian mixture model revealed that the distribution of the estimated distance between eyes could be divided into two clusters, with a mixing ratio of 0.11 for Group 1 (subadult) and 0.89 for Group 2 (adult). Most individuals belonging to Group 1 appeared during the winter months of December to March, indicating that subadults were weaned primarily during this season. Consequently, reproduction of the Okinawa spiny rat is thought to be limited in autumn and winter.
期刊介绍:
Mammal Study is the official journal of the Mammal Society of Japan. It publishes original articles, short communications, and reviews on all aspects of mammalogy quarterly, written in English.