Ecology of some Avian and Mammalian Pestrs

Abstract

1. REPRODUCTION IN THE INDIAN GERBILLE, TATERA INDICA INDICA (HARDWICKE) Data on reproduction of Tatera indica indica were obtained from 400 specimens trapped from irrigated fields and adjacent wastelands in Lyallpur district (Punjab, Pakistan). Reproductively active males were found throughout the year except in December. Pregnancy was recorded from March to September, but the greatest intensity was observed in March-May and August-September. The two periods of high pregnancy coincided the period of new growth of vegetation and the subsequent improving plant and animal nutrition. The average number of embroys per littler for 36 females was 6.33± .308 and the average number of placental scars in 50 post-parturient females was 6.38±.304. The prolonged period of reproduction and large litter size of the present population of the gerbille was thought to be related to rich and abundant food available from irrigated fields. 2. FIELD BIOLOGY OF MUS MUSCULUS AND MUS BOODUGA IN THE CULTIVATIONS OF PUNJAB Reproduction biology and composition of Mus musculus and M. booduga populations were studied from specimens collected from irrigated fields of Lyallpur District and vicinity. The males of both the species were found to breed throughout the year. Female M. musculus bred all year around, but female M. booduga ceased to reproduce from October through December. The intensity of breeding varied from season to season. The litter size determined from the count of embroys was 5.85±.28 in M. muculus and 5.87±.33 in M. booduga. The young adult females tended to produce smaller litters than the older females. The age structure of the two populations was also studied. There was a general tendency for the adults to dominate in the samples. The ratio of the two sexes was skewed in favour of the males. 3. ECOLOGY OF THE SOFT-FURRED FIELD RAT, MILLARDIA MELTADA A study on ecological distribution, breeding biology and population structure of the soft-furried field rat, millardia meltada was conducted in cultivated areas of Lyallpur and Rahim Yar Khan districts. As the results of 2740 trap nights, 134 specimens were caught. Most of these specimens were taken from sugarcane, fodder and vegetable fields. Fields margin and other similar elevated sites were preferred by the rat. Analysis of data on reproduction indicated that males remained fecund throughout the year; winter being the period of minimum fecundity. Pregnancy peaks occurred before and after the rainy season. During the winter season the females ceased to reproduce. The average litter size was 5.07±0.305 (Embroy count) and 6.82±0.405 (Placental scar count). Seasonal variation in population structure was related to the intensity of reproduction. The sex ratio did not deviate from expected 1:1. 4. REPRODUCTIVE CYCLE AND POPULATION STRUCTURE OF THE COMMON PLAM SUIRREL, FUNAMBULUS PENNANTI To study the reproductive biology and population structure Funambulus pennant wroughton, 348 specimens were collected over a period of 15 months extending from February 1974 to April 1975. The males were found to be reproductively active from January through October. Although pregnancies were recorded from April to September, yet most of them were concentrated in the month from April through June. The average number of embroys per pregnant female was 3.23±.119 (range, 2-5; N; 30). The composition of population varied from one part of the year to another. From March until the second week of the June the trappable population were made up of entirely adults. Recruitment of litters started in June and continued till September. Sexual maturity was attainted at about 7 to 11 months of age. Although the overall male to female ratio did not deviate from1:1, yet the proportion of adults during spring and summer samples significantly skewed (at 95 percent level of significance) in the favour of the males. 5. DISTRIBUTION OF BANDICOOT AND MOLE RAT IN THE CROPLANDS OF THE PUNJAB This study describe the microdistribution of B. bengalensis and N. indica in the cultivations of the central Punjab and attempts to know how cropping practice might have effected the rats abundance in the area. Nesokia was found to be more subterranean than the bandicoot. Both the rats infested a variety of crops, of which sugarcane, wheat, and rice seemed to receive maximum damage. The bandicoots were confined mainly to the croplands whereas the Nesokia infested both croplands and waste habitats. In the croplands bandicoot population was mainly concentrated in the sugarcane fields. Increase in the number of bandicoots was related to intensive cultivation of sugarcane in the area. 6. REPRODUCTION, PRENATAL MORTALITY AND POPULATION STRUCTURE IN NESOKIA INDICA AND BANDICOTA BENGALENSIS This study aims at knowing the reproductive biology population composition of the bandicoot and mole-rat populations. The male bandicoots bred throughout the year and the proportion of reproductively active males ranged from 60 to 88 percent. The female bandicoots ceased reproducing or at least endured retardation in reproductive activities during the winter season. In contrast, the mole-rats appeared to stop or to decelerate breeding during the summer season. In the bandicoots overall litter size (based on the embroys count) was 6.21±.67 and in mole-rat it was 4.07±.54. The average number of placental scars per post-parturient female bandicoot and mole-rat was 6.06± .97 and 5.30± .78, respectively. The proportion of females and males in both the rats was essentially close to the theoretical 1:1 ratio. Neither age nor season had any appreciable effect on the proportions of the two sexes. 7. AGE DETERMINATION AND COMPARATIVE BODY AND SKULL MORPHOMETERY OF NESOKIA INDICA AND BANDICOTA BENGALENSIS A total of 179 specimens of Nesokia indica and bandicota bengalensis was collected from March, 1976 to January. 1978. On the basis of wear pattern on the maxillary molars, the rats were segregated into five wear classes. But better results were obtained, when such characters as the body weight, body length, reproductive conditions were used in combination with wear pattern. The bandicoots did not exhibit any sexual dimorphism in the elements of the body and skull measured in this study. However, the males of the mole rat weighed heavier than the females and their body and tail was also longer. Intra-population variations and variations due to ager were also studied. 8. NON-GEOGRAPHIC VARIATIONS IN FUNABULUS PENNANTI A total of 351 specimens of squirrels collected from Faisalabad district was segregated into five wear classes on the basis of wear on molariform teeth. The results were consolidated by the other parameters of skull and body. Three elements Viz., body weight, body length and mastoid breath evidence perceptible increase even often the squirrel had attained sexual maturity. The female averaged heavier than the males. Further, their mandibular length and basioccipital breath were also significantly larger than in the males. Only one element, namely, the Zygomatic breath was larger in males. The values of coefficient of variability were generally larger in pre-adult stages than those in the adults. CV values for the body weight of the adults were relatively larger, 9 in the males and 12 in the females. But, CV values for the skull were least variable; they varied from 1.91 to 6.60 in the males and from 1.05 to 4.64 in the females. 9. RODENT DAMAGE TO WHEAT CROP IN FAISALABAD DISTRICT A survey of rodent damage to wheat crop in Faisalabad district was conducted within twenty-nine days of the harvest. Examination of 8502 hills from 278 plots revealed that more than 78.1% of the plots had been damaged by rodents. Tiller cutting by rodents in these plots varied from 0 to 44% whereas the overall average approximated 7.5%. Plots adjacent to sugarcane received the greatest damage. The percentages of damaged hills and cut tiller were significantly correlated (r=+.903, p.001; d.f. =30). The relationship was best prepresentated by the regression equation Y = .352 + .513 X Where X is the percentage of damaged hills and Y is the percentage of cut tillers. Intensive trapping in Wheat and adjacent crops and other microhabitats revealed that six species of rodents were associated with the crop. Of these bandicota bengalensis, Tatera indica, Millardia meltada andMus musculus were considered, in order of importance, to be serious pests of wheat. Tatera indica was predominant in and around wastelands whereas the other three species dominated in fields adjacent to sugarcane. Control implication and economic importance of rodents were also discussed. 10. SOMW ADDITIONAL INFORMATION ON RODENT DAMAGE TO WHEAT IN CENTRAL PUNJAB Rodent damage to the standing crop of wheat was estimated for four districts of central Punjab. The study was conducted in April 1978, 20 days within harvest. On the whole 10.9 percent of the hills and 5.1 percent of the tillers were damaged by rodents. A clear-cut positive relationship between the extent of losses and intensity of sugarcane plantation could not be established. Making allowances for the gains resulting from regeneration and compensatory growth in rodent damage plants and for the losses inflicted at sowing and after maturity of the grains, it was estimated that the rodents reduced the potential yield of wheat by 5%. 11. RODENT PROBLEM IN SUGARCANE FILEDS Pattern of rodent infestation and damage to sugarcane was studied in three districts of central Punjab. The rodents attacked mainly the roots and basal nodes. About 11% of the canes sampled were rat damage. In these damage canes 19% of the cane tissue was completely damaged. It was estimated that rat depredations might result in 4 to 15 percent of loss in sugarcane field. A programme for inhibiting rodent populations in the croplands was also proposed. 12. EFFECT OF FLODDING OF RODENTS IN WHEATLANDS Variation in the intensity of rainfall during 1976-79 afforded an opportunity to study the effect of rain on rodent abundance in the wheatland near Faisalabad. It was found that relatively heavy rains in February 1979 had considerably decreased rodent abundance and depredation in the wheatfields. 13. FOOD CONSUMPTION PREFERENCE IN NOTHERN PALM SQUIRREL, FUNAMBULUS PENNANTI Consumption rates and food preferences with respect to five most common types of food grains were studied in the northern palm squirrel, funambulus pennant. The order of preference was wheat, millet, rice, corn, and sorghum. The squirrels on the average consumed 6.09gm/squirrel/day when the grains were offered in combinations of two. When only one food item was offered, the rate of consumption was 5-.16gm/squirrel/day. The squirrels preferred water-soaked grains over air-dried ones. 14. PREFERENCES AND INTAKE OF FOOD BY SOME MURID PESTS OF AGRICULTURE Using five most common cereal gains consumption and preferences in the nesokia indica and mus musculus were investigated. In N. indica wheat was the best consumed grain followed by rice, millet, corn and sorghum. In two-seed tests, combination of wheat and rice was the most acceptable food. Mus musculus preferred rice over other grains, whereas the combination of sorghum and millet was best consumed food. 15. PATERN OF RODENT INFESTATION ON SMALL FARMLANDS The pattern of infestation and migration in bandicota bengalensis, rattus meltada, Mus musculus, and Tatera indica was studied from February to april 1978 on a 40 hectare canal irrigated farmland near Faisalabad. The first three species infested sugarcane from six to nine months of the year. They began to migrates to wheatlands in large number after the crop had started booting. Though in much smaller numbers, these species also infested leguminous fodders. Expecting N.indica all species from harvested wheat fields became conventrated in small scattered fields of clovers and grassy banks of irrigation ditches. A strategy for alleviating the rodent problem in the cropland was also proposed. 16. INHABITTING RODENT DAMAGE TO WHEAT CROP To protect the wheat crop from rodent attack a rodent control programme was conducted over eight 6-acre experimental blocks, four of which were used as treatment and the other four as reference blocks. The bait used consisted of 96% wheat grains, 2% refined cotton oil and 2% zinc phosphide. The technique comprised of baiting rats burrows in recently harvested sugarcane fields and surface baiting in wheat fields. As the result of the poisoning programme damage to wheat tillers declined to 3.2% and the density of rat burrows in the treatment blocks reduced to 2.2 burrows/acre whereas the damage to wheat tillers in reference block being 12.4% and the density of burrows 9.8/acre.