Introduction

Rodents are regarded as unwelcome associate of humans as pests since time immemorial. They cause various loss to production systems like agriculture, horticulture and forestry and stored food grains (Amri and Longkumer, 2018; Kaur et al., 2016; Kocher and Parsad, 2003). They have the ability to adapt to a wide variety of habitats (Prashad, 1999). The cause 5-10% damage to agricultural crops at pre-harvest stage (Sharma and Singh, 2017; Babbar et al., 2014). Their role in transmission of various public health diseases like plague, leptospirosis, rat bite fever, leishmaniasis etc are well known (Singla et al., 2015; Singla et al., 2008; Rosa et al., 2007; Singla et al., 2003; Anantharaman 1966, Huq et al., 1985; Khatoon et al., 2004). Out of total 103 rodent species found in India, only over a dozen species are regarded as of economic importance. The species of rats and mice inhabiting crop fields in Punjab Indian mole rat are Bandicota bengalensis, Milardia meltada, Tatera indica, Indian bush rat, Golunda ellioti Gray, short tailed mole rat, Nesokia indica Gray, Mus musculus, Mus booduga and brown spiny mouse, Mus platythrix Bennett. Out of these B. bengalensis is prevailing in irrigated and rainfed areas of Punjab (Anonymous, 2018).

In Punjab, rats and mice cause damage of 4.9% in paddy, 6.4% in sugarcane, 3.9% in groundnut, 4.5% in wheat, 5.9% in peas and 10.7% in winter maize ( Kaur et al., 2018; Anonymous, 2018; Singh et al., 2017). B. bengalensis is a predominant rat of South Asia (Singal and Pasahan, 1993). It is well established in cultivated fields, pasture lands, forests, high mountains, intertidal mangrove zones, semi arid regions and urban areas (Romanach et al., 2005; Malhi and Sheikher, 1986). It is a robust rodent with adults weighing 200-400 g. It has blunt snout with broad muzzle. It can be up to 40 cm long (including the tail) and is considered a pest in the cereal crops and gardens of India and Sri Lanka. Their fur is dark or pale brown dorsally, occasionally blackish, and light to dark grey ventrally. The head-body length is around 250 mm, and the uniformly dark tail is shorter than the head-body length. The diet includes grains, fruits and invertebrates. It destroys cultivated crops in fields. Commonly, it lives in cultivated plains and gardens and is one of the most destructive pests to crops and cultivation. It is nocturnal and fossorial in habit. It digs burrows with characteristic pile of earth around the entrance. The burrow system is extensive and elaborate, consisting of numerous chambers (for breeding, storing food, etc.), galleries and exits or ‘bolt-holes’, which are covered with loose earth (Sheikher 1990). Males and females usually live in separate burrows (Hussain et al., 2016; Kaur and Singh, 2019). Rodents live in underground burrows established by them. Burrowing is just one of a series of activities such as trampling, wallowing, digging and geophagy that can have tremendous impacts on the landscape (Sheikher and Malhi, 1983; Taylor, 1935; Jacob, 1940; Thorp, 1941; Abaturov, 1972; Hole, 1981; Meadows and Meadows, 1991; Stone and Comerford, 1994; Butler, 1995). Burrows give a stable micro-climate and provide small mammal’s defense from intense temperature and from predators on the ground surface (Prashad, 1999). Rodents used the burrows for nesting, food storage, hibernating and shelter from predators during their surface activity (Reichman and Smith, 1987). Paddy-wheat is the dominant cropping system of Indo-Gangatic plains of India (Ali et al., 2016). In our present study attempt has been made to study population build up of B. bengalensis in paddy-wheat cropping system.

Materials and Methods

The study was carried out in the fields of village Dhatt, District Ludhiana, Punjab, India (Ludhiana 30.91°N, 75.85’E) during 2016-17. The main crops grown in this area were wheat, paddy, maize, bajra and vegetables etc. Population dynamics of B. bengalensis was studied in selected field areas having different crops in soil by trapping method for the whole year. Trapping was carried out at monthly interval for consecutive three trap nights from selected field areas. Various other species of rodents like T. indica, M. meltada and M. booduga were also trapped along with B. bengalensis. There were three replications each having one acre area. Sixteen wooden traps acre^-1 were used for trapping rats. Traps were placed in selected areas near the burrow openings. The number of burrows of different rodent species (acre^-1) was also recorded from fields from where trapping was done to observe the pre-dominance of rodent species. Since most of rodents being nocturnal, the burrows were plugged with soil, late in the evening and freshly re-opened burrows on next day were counted as live burrows.

The population was counted by calculating trap index (Singla et al., 2015):

                                Total no. of species trapped

Trap index (%) =  ---------------------------------------- × 100

                               Total no. of traps× trap nights

The trapped species were analyzed to record other parameters like number and kind of species trapped, sex (male or female) and body weight of species trapped (g).

Assessments of rodent damage at pre-harvest stage of different field crops were recorded. Rodent damage (acre^-1) was assessed by taking five samples of 1m² per field of one acre in two diagonal lines to cover center as well as all the four geographical sides of a field as given by Singla and Babbar (2010). In each sample, total number of tillers and tillers cut by rodents were counted.

                           Average number of cut tillers/m²

Damage (%) =   ---------------------------------------------- × 100

                                   Total number of tillers/m²

2.1.  Statistical analysis

The data of burrow count and trap index were given as mean with standard error (SE).

Results and Discussion

The trap index of different species of rodents captured along with B. bengalensis during trapping at different stages of paddy and wheat crops in the year 2016-17 was recorded. In paddy crop, total number of live burrow count recorded during tillering, panicle initiation, dough, pre-harvesting stages and lean period were 19.5±2.45, 14.5±1.89, 15.8±2.50, 15.5±2.76 and 18.5±3.50, respectively (Table 1). In our study, there was pre-dominance of B. bengalensis over M. musculus and T. indica. Total number of live burrow count recorded was maximum during tillering stage (19.5±2.45) and minimum during panicle initiation stage (14.5±1.89). Total number of live burrow count during panicle initiation, dough, pre-harvesting stages and lean period recorded were 25.6, 18.9, 20.5 and 5.12% lower as compared to tillering stage. There were other species like T. indica, M. booduga and M. musculus were also trapped along with B. bengalensis. Total trap index (%) (including all rodent species) in different stages of paddy during tillering, panicle initiation, dough, pre-harvesting and lean period recorded was 10.00±1.98, 13.38±2.88, 17.00±3.06, 2.00±0.55 and 12.50±2.05, respectively having maximum in dough stage and minimum during pre-harvesting stage. The mean trap index (%) of all the trapped species throughout the year was recorded to be 10.97±2.25. Total trap index (%) during tillering, panicle initiation, pre-harvesting stages and lean period recorded was 41.17, 21.29, 88.23 and 26.47% lower as compared to dough stage.

Trap index (%) of B. bengalensis during tillering, panicle initiation, dough, pre-harvesting stages and lean period recorded was 5.0±1.44, 11.6±2.05, 13.0±3.55, 2.0±0.98 and 12.5±3.44, respectively (Table 1).

Table 1: Trap index (%), cut tillers (%), damage (kg acre-1) and different parameters of trapped B. bengalensis in different stages of paddy crop (Mean±SE)

Trap index (%) of B. bengalensis was recorded to be maximum in dough stage (13.0±3.55) while minimum in pre-harvesting stage (2.0±0.98). In paddy crop, as the total number of B. bengalensis burrows decreases from tillering to pre-harvesting stage there is rise and fall in trap index but during lean period there is rise in trap index due to increase in B. bengalensis burrows(Figure 1).

Figure 1: Relationship of trap index (%) and number of burrow count of B. bengalensis during different stages of paddy crop

Trap index (%) of B. bengalensis during tillering, panicle initiation, pre-harvesting stages and lean period recorded was 61.5, 10.76, 84.6 and 3.84%, respectively lower as compared to dough stage. B. bengalensis achieved high rate of reproduction by producing many large litters during the months when paddy crop was maturing and ripening (Fulk et al.,1981). The sex ratio (male: female) of trapped B. bengalensis recorded during tillering, panicle initiation, dough, pre-harvesting stages and lean period recorded was 1:0.33, 1:2.25, 1:2.25, 0:1 and 1:1, respectively. During panicle initiation, dough and pre-harvesting stages, sex ratio was in favour of females while it was in favour of males in tillering stage, whereas in lean period sex ratio remains constant for both sexes. The weight (g) of trapped B. bengalensis male during tillering, panicle initiation, dough stages and lean period ranged from 212-300, 211-319, 80-250 and 100-302, respectively whereas weight of females ranges from 0-190, 110-303, 56-268, 250-280 and 89-256, respectively. The weight of B. bengalensis was maximum during panicle initiation stage (303 g for female) and minimum during dough stage (105 g for male). Average weight (g) of B. bengalensis during tillering, panicle initiation, dough, pre-harvesting stages and lean period recorded was 229.5±2.76, 236.9±3.05, 155.3±3.87, 265±2.56 and 180.8±3.09, respectively. It was maximum during pre-harvesting stage (265g) while minimum in dough stage (119.56 g) as shown in (Table 1). The % cut tillers and damage (kg acre^-1) recorded in paddy crop were 0.46±0.04 and 11.76±0.71, respectively. Beg et al.,(2010) reported that except for the wheat fields, the house mouse was predominant in the fields of all the crops; its average trap success in the various crops ranged from 3.1 to 6.7%. The average trap success varied from 0.9 to 5.9%; among its better populated crops were sugarcane (5.9%), fodder (3.6%), and cotton (3.2%). In bandicoot rat, the trap success ranged from 0.1% (in the cotton fields) to 5.0% (in the sugarcane fields). The trap success for the bandicoot rat in the wheat-paddy system was somewhat more than what it was recorded for the wheat-sugarcane crops, while the opposite was true for the house mouse (Rattus rattus) and the soft furred field rat (M. meltada)populations (Durr-i-Shahwar et al., 1999 and Beg et al.,2010). 

In wheat crop, total number of live burrow count recorded during tillering, panicle initiation, dough, pre-harvesting stages and lean period recorded were 19.6±2.69, 19.2±1.19, 12.6±1.50, 18.5±2.85 and 19.0±2.57, respectively (Table 2).

Table 2: Trap index (%), cut tillers (%), damage (kg acre-1) and different parameters of trapped B. bengalensis in different stages of wheat crop

In our study, there was pre-dominance of B. bengalensis over M. musculus and T. indica. Total number of live burrow count was maximum during tillering (19.5±2.69) and minimum during dough stage (12.6±1.50). Total number of live burrow count during panicle initiation, dough, pre-harvesting stages and lean period recorded were 2.04, 35.7, 5.61 and 3.06% lower as compared to tillering stage. Like paddy crop, there were other species like T. indica, M. booduga and M. musculus and M. meltada were also trapped along with the B. bengalensis in wheat crop. Total trap index (%) including all rodent species in different stages of wheat during tillering, panicle initiation, dough, pre-harvesting stages and lean period recorded was 11.25±1.28, 3.75±3.88, 17.00±3.06, 2,00±0.55 and 13.40±1.98, respectively having maximum in dough stage and minimum during pre-harvesting stage (Table 2). The mean total trap index (%) of all the trapped species throughout the year was recorded to be 9.48±2.55. Total trap index (%) during tillering, panicle initiation, pre-harvesting stages and lean period recorded was 33.8, 77.9, 88.2 and 21.1% lower as compared to dough stage.

Trap index (%) of B. bengalensis during tillering, panicle initiation, dough, pre-harvesting stages and lean period recorded was 6.25±1.40, 3.75±3.05, 13.9±1.55, 2.9±1.18 and 10.3±2.23, respectively. Trap index (%) of B. bengalensis was recorded to be maximum in dough stage (13.9±1.55) while minimum in pre-harvesting stage (2.9±1.18). In wheat crop, total number of B. bengalensis burrows remain almost same from tillering to lean period stage except dough stage, there is rise and fall in trap index which was maximum during dough stage and then decreases at pre-harvesting stage and again rises in lean period (Figure 2).

Figure 2: Relationship of trap index (%) and number of burrow count of B. bengalensis during different stages of wheat crop

Trap index (%) of B. bengalensis during tillering, panicle initiation, pre-harvesting stages and lean period was recorded to be 55.0, 73, 79.1, 25.8%, respectively lower as compared to dough stage. The sex ratio (male: female) of trapped B. bengalensis recorded during tillering, panicle initiation, dough, pre-harvesting stages and lean period of wheat crop recorded was 1:1.5, 1:0.5, 1:0, 0:1 and 1:0.5, respectively (Table 2). During panicle initiation, dough stages and lean period, sex ratio was in favour of males while it was in favour of females in tillering and pre-harvesting stages. In a study by Sharma and Singh (2018) during monsoon, post-monsoon and spring seasons, sex ratio of T. indica species was in favour of males while it was in favour of females during winter season, which leads to increase in population during winter season. The weight (g) of trapped B. bengalensis male during tillering, panicle initiation, dough stages and lean period ranges from 110-190, 140-179, 180-220 and 85-250, respectively whereas weight of females  during tillering, panicle initiation, pre-harvesting stages and lean period ranges from 80-130, 0-81, 180-268 and 80-210, respectively. The weight of B. bengalensis was maximum during dough stage (220 g for male) and minimum during tillering stage (80 g for male). Average weight (g) during tillering, panicle initiation, dough, pre-harvesting and lean period was recorded to be 128.0±2.09 133.3±3.98, 201.2±2.58, 186.0±3.80 and 180.8±2.30, respectively. It was maximum during dough stage (201.2 g) while minimum in tillering stage (128.0 g) as shown in (Table 2). The % cut tillers and damage (kg acre^-1) recorded in wheat crop were 0.28±0.09 and 7.93±0.99, respectively.

According to Singal and Pasahan (1993) the population of B. bengalensis depicted a linear correlation with growth of crop. The population density of B. bengalensis was maximum at maturity stage of crop, this peak in the population density may be correlated with the availability of sufficient food and shelter in the crop fields (Sood and Ubi, 1975). This evidence supports our result. In paddy and wheat crop, the population density of B. bengalensis was maximum at dough stage. Hence, there was a higher degree of level of damage at the maturity stage as comparison to other growing stages of crop (Kumar and Pasahan, 1992). Sagar and Bindra (1973) and Shekhar (1990) have also noticed in B. bengalensis two different breeding seasons i.e. one around March to April and the other around August to September corresponding to the maturity stage of the crops. Thus, periodicity of bandicoot reproduction in wheat crop could be correlated with the availability of food and shelter, consequent of which more number of young ones were trapped (Sood and Ubi, 1975).

Conclusion

There was pre-dominance of B. bengalensis over other species.  In both crops, as number of B. bengalensis burrows decreases there is rise and fall in trap index and it was maximum during dough stage in wheat crop. During panicle initiation, dough and pre-harvesting stages, sex ratio was in favour of females which leads to higher population, while it was in favour of males in tillering stage, whereas it was vice versa for wheat crop.

Acknowledgement

The authors are thankful to Indian Council of Agricultural Research (Vertebrate Pest Management) and Head, Department of Zoology, Punjab Agricultural University, Ludhiana for providing financial help and other facilities for this research work.

Reference

Abaturov, B.D., 1972. The role of burrowing animals in the transport of mineral substances in the soil. Pedobiologia 12, 66-261.

Ali, M.N., Alam M.P., Ahmad, E., Shah, A., 2016. Effect of different residue management practices of rice on growth and yield of wheat and soil health in rice-wheat system. International Journal of Bio-resource and Stress Management 7(4), 567–574.

Amri, T., Longkumer J., 2018. Indigenous knowledge on rodent management of the Ao-Nagas of Mokokchung District, Nagaland. International Journal of Bio-resource and Stress Management 9(5), 620–624.

Anantharaman, M., 1966. Parasites in Indian rodents with special reference to disease in man and animals. Proceeding of Indian Rodent Symposium, Calcutta, India, 8-11 December, 1961.

Anonymous, 2018. Management of rodents and birds’ In: Package of Practices for Rabi Crops of Punjab, Punjab Agricultural University, Ludhiana, 109–113.

Babbar, B.K., Singla, N. Singh, R., 2014. Impact of village level education and training on adoption of control strategies, their sustainability and reduction in crop losses.  International Journal of Advanced Research 2(7), 672–683.

Beg, M.A., Mushtaq-ul-Hussan, M., Durr-i-Shahwar, S., Nadeem, M.S., 2010. The dynamics of rats and mice populations inhabiting wheat - sugarcane based croplands in central Punjab (Pakistan). Pakistan Journal of Zoology 42, 311–323.

Butler, D., 1995. Zoogeomorphology: Animals as Geomorphic Agents. Cambridge University Press, Cambridge, Massachusetts. 231.

Durr-I-Shahwar, S., Beg, M.A., Mushtaq-Ul-Hassan, M., Khan, A.A., 1999. Inhabiting rodents: I. Distribution and abundance of rat and mice in a wheat-rice based crop land. Pakistan Journal of Agriculture Science 36, 115–121.

Fulk, G.W., Lathiya, S.B., Khokhar, A.R., 1981. Rice field rats of lower Sindh: abundance reproduction and diet. Journal of Zoology 193, 371–390.

Hole, F.D., 1981. Effects of animals on soil. Geoderma 25, 75–112.

Huq, M.M., Karim, M.J., Sheikh, H., 1985. Helminth parasites of rats, house mice and moles in Bangladesh, Pakistan Veterinary Journal 5, 143–144.

Hussain, I., Qureshi, N.A., Anwar, M., Mushtaq, M., 2016. Burrow characteristics of lesser Bandicoot rat (Bandicota bengalensis) in the agro-ecosystem of Porthwar Plateau, Pakistan. Pakistan Journal of Zoology 48, 631–638.

Jacob, A.P., 1940. The fauna of soil. Quarterly Review of Biology 15, 28–58.

Kaur, N., Singla, N., Singh, R., 2016. Efficacy of Tyre Bait Station for Rodenticide Application in Rice Crop Fields during Monsoon Season. Indian Journal of Ecology. 43(1), 354–356.

Kaur, N., Singla, N., Singh, R., 2018. Efficacy of rodenticide bait application for rodent pest management in potato crop. Journal of Entomology and Zoology Studies 6(2), 2149–2152.

Kaur, K., Singh, R., 2019. Burrow structure of lesser bandicoot rat, Bandicota bengalensis during different stages of rice crop in Punjab. Journal of Experimental Zoology India 22(1), 331–338.

Khatoon, N., Bilqus, F.M., Shahwar, D., Rizwara, A.G., 2004. Histopathologic alteration associated with Syphacis sp. (Nematode) in the intestine of Nesokia indica. Turkish Journal of Zoology 28, 345–351.

Kocher, D.K., Parsad, V.R., 2003. Structural and functional analysis of burrows of three rodent species in wheat fields in sandy and loamy soils in Punjab (India). Mammalia 67(4), 603–605.

  Kumar, P., Pasahan, S.C., 1992. Effect of biotic factors on population fluctuations in sympatric murids. Annals of Arid Zone 31, 93–98.

Malhi, C.S., Sheikher, C., 1986. Burrowing and hoarding behaviour of Bandicota bengalensis wardi in wheat crop at Srinagar (Garhwal)-Himalayas. Journal of Environmental Biology 7, 197–200.

Meadows, P.S., Meadows, A., 1991. The environmental impact of burrowing animals and animal burrows. Proceedings of a symposium held at the Zoological Society of London, May, l990. Zoological Society of London, 319.

Prashad, V.R., 1999. Rodent control in India. Integrated Pest Management Review 4, 97–126.

Reichman, O.J., Smith, S.C., 1987. Burrows and burrowing behavior by mammals. Current Mammology 2, 197–244.

Romanach, S.S., Reichman, O.J., Seabloom, E.W., 2005. Seasonal influences on burrowing activity of a subterranean rodent, Thomomys bottae. Journal of Zoology London 266, 319–325.

Rosa, R., Rizzoli, A., Ferrari, N., Pugliese, A., 2007. Models for host parasite interactions in micromammals. In: Morand, S., Krasnov, B.R., Poulin, R. (Eds.), Micromammals and Macroparasites: from evolutionary ecology to management. Springer, Tokyo, 319–48.

Sagar, P., Bindra, O.S., 1973. Species composition and fluctuation in population of rats and mice in sugarcane at Ludhiana. Abstract 63. The National Academy of Sciences, India. Forty Second Annual Session. Allahabad. March 4–6, 1973.

Sharma, A., Singh, R., 2018. Effect of abiotic factors on burrow density of Indian gerbil, Tatera indica (Hardwicke) (Rodentia: Muridae) in Punjab. Journal of Entomology and Zoology Studies. 6(4), 1508–1513.

Sheikher, C., Malhi, C.S., 1983. Territorial and hoarding behaviour in Bandicota sp. and Mus sp. of Garhwal Himalayas. Proceeding of Indian National Science Academy 49, 332–335.

Sheikher, C., 1990. Proceedings of the Sixth All India Workshop on Rodent control at Nauni-Solan (HP). ICAR. April 17-18, 13

Singal, R.K., Pasahan, S.C., 1993. Exploration on the status of the lesser bandicoot rat, Bandicota bengalensis Gray in Wheat Crop. Annals of Arid Zone 32(4), 241–244.

Singh, R., Singla, N., Kaur, N., 2017. Determination of method and timings of rodent control in direct seeded and transplanted basmati rice crops. The Bioscan 12(2), 701–705.

Singla, N., Babbar, B.K., Singh, R., Kaur, N., 2015. Rodent population assessment methods. In: Rodent Pests: A Practical Guide for Management. Punjab Agricultural University, Ludhiana, 40–43.

Singla, N., Babbar, B., 2010. Rodent damage and infestation in wheat and rice crop fields: District wise analysis in Punjab state. Indian Journal of Ecology 37(2), 88–184.

Singla, L.D., Singla, N., Parshad, V.R., Juyal, P.D., Sood, N.K., 2008. Rodents as reservoirs of parasites in India. Integrative Zoology 3, 21–26.

Singla, L.D., Singla, N., Parshad, V.R., Sandhu, B.S., Singh, J., 2003. Occurrence and pathomorphological observations on Cysticercus fasciolaris in bandicoot rats in India. In: Singleton, G.R., Hinds, L.A., Krebs, C.J., Spratt, D.M. (Eds.) Rats, mice and people: rodent biology and management. ACIAR, Australia, 57–59.

Singla, N., Dhar, P., Singla, L.D., Gupta, K., 2015. Patho-physiological observations in natural concurrent infections of helminth parasites of zoonotic importance in the wild rodents, Bandicota bengalensis. Journal of Parasitology Diseases 40(4), 1435–1442.

Sood, M.L., Ubi, B.S., 1975. Population fluctuations of sympatric murids occuring in the fields of PAU. Ludhiana. All India Rodent Seminar, Ahemdabad, 76–80.

Stone, E., Comerford, N.B., 1994. Plant and Animal activity below the solum whole regolith pedology No. 34. Madison, WI Soil Science Society of America, 20.

Taylor, W.P., 1935. Some animal relations to soils. Ecology 16, 127–136.

Thorp, J., 1941. Effects of certain animals that live in soils. Science Monthly 68, 91–180.