Author Institution: Department of Entomology, Punjab Agricultural UniversityDevelopment of the lesser bandicoot rats was studied under caged conditions. 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

Bindra, O. S.

Sagar, Prem

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REPRODUCTIVE PATTERNS OF CAPTIVE LESSERBANDICOOT RAT {BANDICOTA BENGALENSISGRAY) IN THE PUNJAB1PREM SAGAR and O. S. BINDRA, Department of Entomology, Punjab Agricultural University,Ludhiana, Punjab, IndiaAbstract. Development of the lesser bandicoot rats was studied under caged condi-tions. Early development of both sexes was similar. Walking started (14 days) atabout the time sensory organs became functional. Body weight in males continuedto increase for about 9 months. After about 5 months, weights of females fluctuatedwith pregnancies. Sexual maturity was attained by 60 days in females, slightlyearlier in males (51 days). A female might produce 9 litters annually; mean littersize was 5.4 Sex ratio was 41% males.OHIO J. SCI. 78(1): 44, 1978The lesser bandicoot rat {Bandicotabengalensis (Gray)) is of great economicimportance. Though most rats are noc-turnal, this species may be active at allhours. During the day its long, deepburrows are extended (Kamath 1961,Deoras 1967, Sagar and Bindra 1971).These burrows in banks and under railtracks may result in indirect damage:loss of irrigation water, flooding, or de-railment of trains. At night, the activityis confined to collecting and storing food-stuffs. A single burrow has been foundto contain 7.3 kg of wheat heads (Sagarand Bindra 1971), and the literature con-tains many other reports regarding theirhoarding behaviour. Males and femalesusually live in separate burrows.To control this rat, detailed knowledgeof its biology is essential. However, nostudies have been done in the Punjab andfew in the adjoining states. To fill thislacuna, the post-natal development andreproductive patterns were studied, andresults are presented in this paper.MATERIALS AND METHODSThe rats, collected between March and Mayby trapping with Wonder traps (multiple-catchlive traps manufactured in Bombay) and by dig-ging out burrows, were examined for ectopara-sites before bringing them to the laboratory.Infested rats were dusted with 10% BHC dust.Cages. Outdoor, galvanized-metal, rat-breeding cages (2.5 x 0.8 x 0.8 m) divided into 3Manuscript received December 7, 1976 andin revised form September 26, 1977 (#76-94).compartments were maintained in dense shadetrees adjacent to the laboratory. Wire-nettingprovided ventilation, and each compartmenthad a 30 x 30 cm glass pane for observing therats. Food trays were hung from the back wallof the cage, and a watering trough was securedabout 40 cm away from the tray.A small wooden box (30 x 20 x 20 cm) with asliding door on one side and a 6 cm entry holeon the other was provided in each compartmentof the cage. Packing straw was placed neareach box, and each female made a nest in thebox. The wooden boxes were taken out andcleaned every fortnight, and fresh straw wasprovided.Food (mixture of Bengal gram flour, maizeflour, and wheat flour in dough form, enrichedwith 2% each of multivitamins and bone cal-cium; or grains of husked rice, pearl-millet,and wheat) was renewed every morning; water,twice a day. Supplies were always in excess ofrequirements. The fecal pellets and hair wereremoved daily, and the cages and feeding trayswere washed weekly.Reproductive biology. Field-collected ratswere kept isolated for 4-5 weeks in 45 x 30 x 22.5cm wire-mesh cages until they were paired on20 June 1970 in the outdoor cage compartments.The rats were observed twice daily. Whenyoung were born, they were counted, sexed, andmarked by toe clipping. The next day, and atweekly intervals, the young were weighed andthe body, tail and hind foot lengths were re-corded. Post-natal development was observeddaily, special attention being paid to sexualdevelopment.Pairing of first generation. Young wereweaned at the age of 3 weeks. Those from thesame litter were kept together until 11 February1971 when they were divided into groups of 1female, 1 male; 2 females, 1 male; 3 females, 1male and moved into separate compartments ofthe outdoor cage.44Ohio J. Sci. BANDICOOT RAT REPRODUCTION 45RESULTS AND DISCUSSIONPost-natal development. The newly-born young were pink, with ears andeyes closed, devoid of hair but with 1.5-2mm long vibrissae. Opening of earflaps took 3-5 days. The skin startedturning grey on the 4th day and wascompletely grey on the 7th day; the bodywas completely covered with fine hair bythe 12th day. The incisors were firstseen on the 7th day and attained a lengthof O.G cm in the lower jaw and 1 cm in theupper jaw at the age of 14 days. Theteats, which could clearly be seen by the7th day, varied from 13 to 16 in number(mean = 14.3 ±0.9). The young startedwalking when 14 days old. The eyesopened after 13 to 16 days; the externalauditory meatus, after 17-20 days. Thesefindings are similar to those of Spillett(1968) in Calcutta.Growth rates. Prior to weaning at 3weeks, body extension was the mostrapid; after weaning increases in bodyweight were greater. After about 6weeks, growth rates markedly declined.Early development in males and femaleswas similar. While body weight inmales continued to increase for aboutnine months, other growth parametershad leveled off between 120 and 180days. After about 5 months femalesstarted producing pups, and fluctuationsoccurred in their body weights due topregnancies and deliveries. In the initial5 months, growth in males and femaleswas similar. These observations aresimilar to those of Spillett (1968), al-though he indicated a continuing increasein weight during a 13-month study period.BREEDING HABITSAge at puberty. The testes descendedinto the scrotal sac at 34-81 days mean(51.2 ="= 11.4 days). The vaginal perfora-tion occurred 41-102 days (mean 60.3="=13.8 days) after birth. Thus pubertywas attained in about 51 days in malesand 60 days in females. Spillett's (1968)few observations are within these ranges.Autumn-born young took longer thanthose in spring litters.The first litter was produced at an ageof 93, 163, 168, 201, 203, and 223 days in7 different females. Bindra and Sagar(1968) reported that Rattus meltada fe-males produced their first litter at the ageof 108 to 335 days and that young bornduring one breeding season usually pro-duced their first litter during the follow-ing breeding season. In the presentstudies, young born during August-December reproduced the followingMarch-July, except for one female bornin August that littered the followingNovember.Breeding seasons. Of the field-collectedadult rats used to make 3 pairs on 20June 1970 in outdoor, rat-breeding cages,2 females died without reproducing. Thethird female produced 7 litters fromAugust 9, 1970 to April 7, 1971: on8/9/70 (1 young), 8/30/70 (5 young),10/4/70 (8 young), 11/8/70 (5 young)12/10/70 (9 young), 3/15/71 (4 young),4/7/71 (10 young).In the next breeding season, the origi-nal field-collected rats and their young(born during August-December) pro-duced young from March 7, 1971 toAugust 26, 1971. Thus, births occurredthroughout the year except during Jan-uary, February, and September; Marchand August were months of peak breed-ing. Spillett (1968) found that in Cal-cutta this species bred throughout theyear. Srivastava et al (1971), on theother hand, reported that it bred onlyduring 2 seasons: March to May andOctober to December.Gestation period. Mating was not ob-served. The minimum period between 2consecutive parturitions among the 16cases studied was 21 days. The gesta-tion period, was therefore, considered 21days. Spillett (1968) reported that inKolar (Mysore State) the gestation periodin this species was 23 days. For R.meltada, Bindra and Sagar (1968) re-ported gestation periods of 20 days or lessin the Punjab. According to Clegg andClegg (1963) it is 21 days in Rattusnorvegicus. The figures of 47 days forRattus rattus and 39.5 days for T. indicareported by Deoras (1967) may be ex-plained by lactation effects and delayedimplantation.Numbers of litters per year and litter size.Litters usually were produced at night.An individual female produced 1-5 littersduring August-December and 2-4 littersduring March-July. Thus, in one year46 P. SAGAR AND O. S. BINDRA Vol. 78in the Punjab as many as 9 litters maybe produced. In R. meltada the maxi-mum number of litters produced in ayear in the Punjab was 7 (Bindra andSagar 1968). Burton (1962) and othersreported that R. rattus and R. norvegicusfemales produced 5-6 litters in a year.Thus, it can be concluded that littering inB. bengalensis is more than in many otherspecies of rats.In 29 litters obtained in the laboratory,size varied from 1 to 10, the mean being5.4±2.6. Sagar and Bindra (1971) foundup to 15 newlyborn young with a singlefemale of this species in burrows. Othershave cited mean litter sizes of 6.2 or more(Spillett 1968). The maximum littersize in R. meltada was 8 in the laboratory(Bindra and Sagar 1968); in R. rattus,litter size varied from 4 to 6 (Deoras1967). Thus, the litter size in B. ben-galensis may be similar to that of theother common species of rats in India.Sex-ratio. An examination of 155young showed that 41% were males and59% females. Thus, the male:femaleratio of 2:3 was similar to the 44% and38% in Maharashtra, but different fromthat reported in Madras (55.7% males)or in 3 Bombay godowns (61% males)(See Spillett 1968).Longevity. One field-collected adultfemale survived for 1.75 years in thelaboratory. The laboratory-born indi-viduals survived for a maximum of about1.5 years. This is much longer than thelife span (170 days) reported by Spillett(1968) for this species under naturalconditions.Acknowledgments. The help rendered by Sh.Harvans Lai Patial, Laboratory Attendant, andWilliam B. Jackson, Bowling Green State Uni-versity for assistance with manuscript prepara-tion is acknowledged. This paper is based ona Ph.D. dissertation by the first author. Pun-jab Agricultural Univ., Ludhiana, India.LITERATURE CITEDBindra, O. S. and Prem Sagar 1968 Breedinghabits of the field rat Millardia meltada(Gray). J. Bombay Nat. Hist. Soc. 65:477-81.Burton, M. 1962 Systematic Dictionary ofMammals of the World. Museum PressLimited. London, 307 pp.Clegg, P. and A. C. Clegg 1963 Biology ofthe Mammal. Heinemann, London. 437 p.Deoras, P. J. 1967 Laboratory breeding oftwo rats. Curr. Sci. 36: 406-407.Kamath, M. K. 1961 Study on Bombay rats,rat burrows, and ectoparasites in Mahimarea. Unpubl. M.S. thesis, Dept. of Ento-nology, Haffkine Inst. Bombay.Sagar, Prem and O. S. Bindra 1971 A note onthe burrowing pattern of the lesser bandicootrat, Bandicota bengalensis (Gray) in the Pun-jab. Proc. Internat. Symp. Bionomics andControl of Rodents, Kanpur, India, 29 Sept.-2 Oct., 1968. p. 55-56.Spillett, J. J. 1968 The ecology of the lesserbandicoot rat in Calcutta. Bombay Nat.Hist. Soc. 223 pp.Srivastava, A. S., R. S. Tripathi and G. P.Awasthi 1971 Laboratory breeding tech-nique for field rats. Proc. Intern. Symp.Bionomics and Control of Rodents, Kanpur,India, 29th Sept.-2 Oct., 1968. p. 53-54.

Reproductive Patterns of Captive Lesser Bandicoot Rat (Bandicota Bengalensis Gray) in the Punjab

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Reproductive Patterns of Captive Lesser Bandicoot Rat (Bandicota Bengalensis Gray) in the Punjab

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