sign in sign up
<<
Home , Bandicota, Lesser bandicoot rat, Rat, Rattus

REPRODUCTIVE PATTERNS OF CAPTIVE LESSER { BENGALENSIS GRAY) IN THE PUNJAB1

PREM SAGAR and O. S. BINDRA, Department of Entomology, Punjab Agricultural University, Ludhiana, Punjab, Abstract. Development of the lesser bandicoot was studied under caged condi- tions. Early development of both sexes was similar. Walking started (14 days) at about the time sensory organs became functional. Body weight in males continued to increase for about 9 months. After about 5 months, weights of females fluctuated with pregnancies. Sexual maturity was attained by 60 days in females, slightly earlier in males (51 days). A female might produce 9 litters annually; mean litter size was 5.4 Sex ratio was 41% males. OHIO J. SCI. 78(1): 44, 1978

The {Bandicota compartments were maintained in dense shade trees adjacent to the laboratory. Wire-netting bengalensis (Gray)) is of great economic provided ventilation, and each compartment importance. Though most rats are noc- had a 30 x 30 cm glass pane for observing the turnal, this may be active at all rats. Food trays were hung from the back wall hours. During the day its long, deep of the cage, and a watering trough was secured are extended (Kamath 1961, about 40 cm away from the tray. A small wooden box (30 x 20 x 20 cm) with a Deoras 1967, Sagar and Bindra 1971). sliding door on one side and a 6 cm entry hole These burrows in banks and under on the other was provided in each compartment tracks may result in indirect damage: of the cage. Packing straw was placed near loss of irrigation water, flooding, or de- each box, and each female made a nest in the box. The wooden boxes were taken out and railment of trains. At night, the activity cleaned every fortnight, and fresh straw was is confined to collecting and storing food- provided. stuffs. A single has been found Food (mixture of Bengal gram flour, maize to contain 7.3 kg of wheat heads (Sagar flour, and wheat flour in dough form, enriched and Bindra 1971), and the literature con- with 2% each of multivitamins and bone cal- tains many other reports regarding their cium; or grains of husked , pearl-millet, and wheat) was renewed every morning; water, hoarding behaviour. Males and females twice a day. Supplies were always in excess of usually live in separate burrows. requirements. The fecal pellets and hair were To control this rat, detailed knowledge removed daily, and the cages and feeding trays of its biology is essential. However, no were washed weekly. studies have been done in the Punjab and Reproductive biology. Field-collected rats were kept isolated for 4-5 weeks in 45 x 30 x 22.5 few in the adjoining states. To fill this cm wire-mesh cages until they were paired on lacuna, the post-natal development and 20 June 1970 in the outdoor cage compartments. reproductive patterns were studied, and The rats were observed twice daily. When results are presented in this paper. young were born, they were counted, sexed, and marked by toe clipping. The next day, and at MATERIALS AND METHODS weekly intervals, the young were weighed and The rats, collected between March and May the body, and hind foot lengths were re- by trapping with Wonder traps (multiple-catch corded. Post-natal development was observed live traps manufactured in Bombay) and by dig- daily, special attention being paid to sexual ging out burrows, were examined for ectopara- development. sites before bringing them to the laboratory. Pairing of first generation. Young were Infested rats were dusted with 10% BHC dust. weaned at the age of 3 weeks. Those from the Cages. Outdoor, galvanized-metal, rat- same litter were kept together until 11 February breeding cages (2.5 x 0.8 x 0.8 m) divided into 3 1971 when they were divided into groups of 1 female, 1 male; 2 females, 1 male; 3 females, 1 Manuscript received December 7, 1976 and male and moved into separate compartments of in revised form September 26, 1977 (#76-94). the outdoor cage. 44 Ohio J. Sci. BANDICOOT RAT REPRODUCTION 45

RESULTS AND DISCUSSION males produced their first litter at the age Post-natal development. The newly- of 108 to 335 days and that young born born young were pink, with ears and during one breeding season usually pro- eyes closed, devoid of hair but with 1.5-2 duced their first litter during the follow- mm long vibrissae. Opening of ear ing breeding season. In the present flaps took 3-5 days. The skin started studies, young born during August- turning grey on the 4th day and was December reproduced the following completely grey on the 7th day; the body March-July, except for one female born was completely covered with fine hair by in August that littered the following the 12th day. The incisors were first November. seen on the 7th day and attained a length Breeding seasons. Of the field-collected of O.G cm in the lower jaw and 1 cm in the adult rats used to make 3 pairs on 20 upper jaw at the age of 14 days. The June 1970 in outdoor, rat-breeding cages, , which could clearly be seen by the 2 females died without reproducing. The 7th day, varied from 13 to 16 in number third female produced 7 litters from (mean = 14.3 ±0.9). The young started August 9, 1970 to April 7, 1971: on walking when 14 days old. The eyes 8/9/70 (1 young), 8/30/70 (5 young), opened after 13 to 16 days; the external 10/4/70 (8 young), 11/8/70 (5 young) auditory meatus, after 17-20 days. These 12/10/70 (9 young), 3/15/71 (4 young), findings are similar to those of Spillett 4/7/71 (10 young). (1968) in Calcutta. In the next breeding season, the origi- Growth rates. Prior to weaning at 3 nal field-collected rats and their young weeks, body extension was the most (born during August-December) pro- rapid; after weaning increases in body duced young from March 7, 1971 to weight were greater. After about 6 August 26, 1971. Thus, births occurred weeks, growth rates markedly declined. throughout the year except during Jan- Early development in males and females uary, February, and September; March was similar. While body weight in and August were months of peak breed- males continued to increase for about ing. Spillett (1968) found that in Cal- nine months, other growth parameters cutta this species bred throughout the had leveled off between 120 and 180 year. Srivastava et al (1971), on the days. After about 5 months females other hand, reported that it bred only started producing pups, and fluctuations during 2 seasons: March to May and occurred in their body weights due to October to December. pregnancies and deliveries. In the initial Gestation period. Mating was not ob- 5 months, growth in males and females served. The minimum period between 2 was similar. These observations are consecutive parturitions among the 16 similar to those of Spillett (1968), al- cases studied was 21 days. The gesta- though he indicated a continuing increase tion period, was therefore, considered 21 in weight during a 13-month study period. days. Spillett (1968) reported that in Kolar (Mysore State) the gestation period BREEDING HABITS in this species was 23 days. For R. Age at puberty. The testes descended meltada, Bindra and Sagar (1968) re- into the scrotal sac at 34-81 days mean ported gestation periods of 20 days or less (51.2 ="= 11.4 days). The vaginal perfora- in the Punjab. According to Clegg and tion occurred 41-102 days (mean 60.3="= Clegg (1963) it is 21 days in 13.8 days) after birth. Thus puberty norvegicus. The figures of 47 days for was attained in about 51 days in males Rattus rattus and 39.5 days for T. indica and 60 days in females. Spillett's (1968) reported by Deoras (1967) may be ex- few observations are within these ranges. plained by lactation effects and delayed Autumn-born young took longer than implantation. those in spring litters. Numbers of litters per year and litter size. The first litter was produced at an age Litters usually were produced at night. of 93, 163, 168, 201, 203, and 223 days in An individual female produced 1-5 litters 7 different females. Bindra and Sagar during August-December and 2-4 litters (1968) reported that Rattus meltada fe- during March-July. Thus, in one year 46 P. SAGAR AND O. S. BINDRA Vol. 78 in the Punjab as many as 9 litters may 1.5 years. This is much longer than the be produced. In R. meltada the maxi- life span (170 days) reported by Spillett mum number of litters produced in a (1968) for this species under natural year in the Punjab was 7 (Bindra and conditions. Sagar 1968). Burton (1962) and others Acknowledgments. The help rendered by Sh. reported that R. rattus and R. norvegicus Harvans Lai Patial, Laboratory Attendant, and females produced 5-6 litters in a year. William B. Jackson, Bowling Green State Uni- Thus, it can be concluded that littering in versity for assistance with manuscript prepara- B. bengalensis is more than in many other tion is acknowledged. This paper is based on a Ph.D. dissertation by the first author. Pun- species of rats. jab Agricultural Univ., Ludhiana, India. In 29 litters obtained in the laboratory, size varied from 1 to 10, the mean being LITERATURE CITED 5.4±2.6. Sagar and Bindra (1971) found Bindra, O. S. and Prem Sagar 1968 Breeding habits of the field rat meltada up to 15 newlyborn young with a single (Gray). J. Bombay Nat. Hist. Soc. 65: female of this species in burrows. Others 477-81. have cited mean litter sizes of 6.2 or more Burton, M. 1962 Systematic Dictionary of (Spillett 1968). The maximum litter of the World. Museum Press Limited. London, 307 pp. size in R. meltada was 8 in the laboratory Clegg, P. and A. C. Clegg 1963 Biology of (Bindra and Sagar 1968); in R. rattus, the . Heinemann, London. 437 p. litter size varied from 4 to 6 (Deoras Deoras, P. J. 1967 Laboratory breeding of 1967). Thus, the litter size in B. ben- two rats. Curr. Sci. 36: 406-407. Kamath, M. K. 1961 Study on Bombay rats, galensis may be similar to that of the rat burrows, and ectoparasites in Mahim other common species of rats in India. area. Unpubl. M.S. thesis, Dept. of Ento- Sex-ratio. An examination of 155 nology, Haffkine Inst. Bombay. Sagar, Prem and O. S. Bindra 1971 A note on young showed that 41% were males and the burrowing pattern of the lesser bandicoot 59% females. Thus, the male:female rat, Bandicota bengalensis (Gray) in the Pun- ratio of 2:3 was similar to the 44% and jab. Proc. Internat. Symp. Bionomics and 38% in Maharashtra, but different from Control of , Kanpur, India, 29 Sept.- 2 Oct., 1968. p. 55-56. that reported in Madras (55.7% males) Spillett, J. J. 1968 The of the lesser or in 3 Bombay godowns (61% males) bandicoot rat in Calcutta. Bombay Nat. (See Spillett 1968). Hist. Soc. 223 pp. Longevity. One field-collected adult Srivastava, A. S., R. S. Tripathi and G. P. Awasthi 1971 Laboratory breeding tech- female survived for 1.75 years in the nique for field rats. Proc. Intern. Symp. laboratory. The laboratory-born indi- Bionomics and Control of Rodents, Kanpur, viduals survived for a maximum of about India, 29th Sept.-2 Oct., 1968. p. 53-54.