Tatera Research Articles

Abundance and taxonomic characterization of chigger mites (Acari: Trombiculidae and Walchiidae) associated with rodents in selected scrub typhus-prone areas in Southern and Western provinces of Sri Lanka

Larval trombiculid mites (chiggers) are the vectors and reservoirs of the potentially lethal infectious disease, scrub typhus (ST) caused by Orientia tsutsugamushi. Small rodents are natural hosts of parasitic larval stage of the chigger mites. This study focused on determining the abundance of chigger mites associated with rodents in Sri Lanka and the taxonomic characterization of field-caught chiggers. Field sampling was conducted in the districts of Galle, and Hambantota of the Southern Province, and Gampaha of the Western Province, in 2019 and 2020. Sampling sites were selected according to the patient distribution. A total of 58 small mammals (rodent species: Rattus rattus (Black rat), Rattus norvegicus (Brown rat), Tatera indica (Indian gerbil), Gollunda ellioti (Indian bush rat) and Suncus murinus (Asian house shrew)) were captured using baited traps. Chiggers from the captured rodents were speciated morphologically by visual inspection and morphometry using a camera-mounted light microscope (x100). A total of 394 chigger mites were collected. Three different genera were identified, including Leptotrombidium, Schoengastiella, and Microtrombicula. Leptotrombidium imphalum (72.59%; n=286) was the predominant species, followed by Schoengastiella punctata (8.12%; n=32). Some specimens were identifiable only up to genus level, Leptotrombidium sp. (3.55%; n=14) and Microtrombicula sp. (4.82%; n= 19). Some (7.11%; n=28) were not trombiculid mites, while 3.81%; n=15 was damaged beyond identification. Leptotrombidium imphalum was detected for the first time parasitizing the murids - Rattus novergicus and Tatera indica in the district of Galle, a new locality. In addition, S. punctata was recorded in a new locality in the Gampaha district, Western province with a new host association, Golunda ellioti. This study emphasizes the need for further entomological surveys in ST disease-endemic areas. Developing a morphological identification key for chigger mites in Sri Lanka is a top priority to facilitate field surveys.

Rodent communities in a neglected grassland landscape: Investigating species-specific responses of grassland rodents to habitat type and shrub presence

Arid grasslands worldwide are transitioning to scrublands due to shrub encroachment, resulting in habitats with varying shrub cover. Shrubs play a crucial role in grassland ecosystems, offering trade-offs to rodents in terms of visibility, shelter, and food availability, thereby affecting their occurrence and distribution. This study explores the link between habitat characteristics and rodent activity and density, focusing on shrub presence. In the Tirunelveli district of southern India, we measured rodent density and activity across three grassland types with increasing shrub presence. Our findings reveal species-specific responses to shrub density. The Soft-furred rat (Millardia meltada) dominated, showing adaptability to different shrub levels, while the black rat (Rattus Rattus) was least represented. Fine-scale analysis indicates a positive association between shrub presence and rodent captures. Grassland obligate species like the Indian gerbil (Tatera indica) exhibited reduced activity in densely shrubbed sites, whereas semi-arboreal species like the Indian palm squirrel (Funumbulus palmarum) showed increased activity. This study underscores the importance of considering habitat structure in grassland ecosystem management for the conservation of rodent diversity and ecosystem health.

Small rodent communities and their associated damage to wheat-groundnut agriculture systems.

Rodents can cause significant damage to wheat-groundnut crops in developing countries, as well as to stored produce and infrastructure, affecting food security and income of small-holder farmers. Wheat (Triticum aestivum) and groundnuts (Arachis hypogea) are important cash crops for local farmers in Pakistan. Field experiments were performed to assess the extent of rodent damage to wheat-groundnut crops throughout their growth stages (i.e, germination, flowering/peg formation and maturity) in the agro-ecological zones of Pothwar Plateau, Pakistan. We used a quadrat method to record the number of damaged crop plants. On the basis of the trapping data four rodent species were captured from wheat-groundnut cropping systems which were responsible for causing damage, i.e., lesser bandicoot rat (Bandicota bengalensis) was the main species, followed by the short-tailed mole rat (Nesokia indica), the Indian gerbil (Tatera indica) and the bush rat (Golunda ellioti). In both crops, the maximum damage was recorded at crop maturity (10.7 and 14.4%, respectively). The lowest reported damage to wheat and groundnuts was at the germination stage (3.5% and 6.0%, respectively). The lower damage reported at germination could be due to availability of non-crop vegetation at field borders that may be a potential factor influencing damage. Our findings clearly show the considerable amount of damage caused by rodents to wheat-groundnut at maturity across all the agro-ecological zones of Pothwar and indicated that the small mammal composition was more related to maturity stage/season of crops, when the availability of food and climatic condition were favorable and having security under crop shelter. More detailed studies are needed to fully understand the population and breeding ecology of the relevant rodent pest species in relation to damage patterns to optimize management beyond individual structural measures.

Dietary Habits of Indian Gerbil Tatera indica Inhabiting Agro-Ecosystem of Pothwar Plateau, Pakistan

Dietary Habits of Indian Gerbil Tatera indica Inhabiting Agro-Ecosystem of Pothwar Plateau, Pakistan

Rodent population dynamics and crop loss estimation due to rodent pests in finger millet based crop lands

Ragi (Eleusine coracana Gaertn ) also known as finger millet is an important millet widely grown in Asia and is the major staple food in southern Karnataka. Rodents are critical vertebrate pests and are regarded as big chaos to agricultural production. In the present studies the rodent population and crop loss due to rodent pest in finger millet crop was analyzed during the year 2022. The studies revealed that with mean trap index of 20.28 the rodent activity in the finger millet crop lands was observed throughout the year and the peak rodent activity was recorded in Kharif and Rabi crop seasons and was less in the dry (summer) seasons. The population was male and adult dominant with a male female ratio of 1:0.92 and adult infant ratio of 1:0.56, respectively. The Shannon index (Hǀ) in finger millet crop lands found to be 1.08 and the peak Shannon index was recorded in the month of August with a highest relative abundance of Bandicota bengalensis, Tatera indica and Mus platythrix rodent species in the finger millet crop lands. The yield loss estimation studies indicated that there was a grain loss of 2.98 q ha-1 in finger millet crop lands with a monetary value of Rs. 10, 662 (US $129.48) per hectare.

Niche partitioning by sympatric civets in the Himalayan foothills of Pakistan.

Niche overlap between sympatric species can indicate the extent of interspecific competition. Sympatric competing species can exhibit spatial, temporal, and dietary adjustments to reduce competition. We investigated spatial, temporal, and dietary niche overlap of sympatric Asian palm civet (Paradoxurus hermaphroditus) and small Indian civet ( Viverricula indica), in and around Pir Lasura National Park, Pakistan. We used remote cameras to determine the frequency and timing of detections to estimate spatial and temporal overlap, and prey remains from scats to estimate dietary overlap. We collected scat samples of Asian palm civet (n = 108) and small Indian civet (n = 44) for dietary analysis. We found low spatial (Oij = 0.32) and temporal (Δ = 0.39) overlap, but high dietary niche overlap (0.9) between these two civet species. Both civet species were detected at only 11 camera sites and small Indian civets were detected most frequently during 2:00-5:00 h and 8:00-10:00 h, whereas Asian palm civets detections were greatest during 20:00-2:00 h. The overall niche breadth of Asian palm civet was slightly narrower (L = 9.69, Lst = 0.31) than that of the small Indian civet (L = 10, Lst = 0.52). We identified 27 dietary items (15 plant, 12 animal) from scats of Asian palm civet including Himalayan pear (Pyrus pashia; 27%), Indian gerbil (Tatera indica; 10%), Rhesus monkey (Macaca mulatta; 4%), and insects (5%). Scat analysis of small Indian civets revealed 17 prey items (eight plant, nine animal) including Himalayan pear (24%), domestic poultry (15%), Indian gerbil (11%), and house mouse (Mus musculus; 5%). Both civet species consumed fruits of cultivated orchard species. Spatial and temporal partitioning of landscapes containing diverse foods appears to facilitate coexistence between Asian palm civets and small Indian civets.

Skull variation in populations of the Indian gerbil Tatera indica (Gerbillinae, Rodentia) sampled across its broad geographic range

Populations of broadly distributed species often exhibit geographic structuring, which is sometimes reflected in phenotype. The monotypic Indian gerbil (Tatera indica) is an example of a widely distributed species, with its range encompassing much of Asia. This study aims to determine if T. indica populations exhibit marked variation in skull morphology—this structure is particularly adaptable and thus could be amenable to show such variation. Furthermore, the potential drivers of skull variation are examined, including the role of climate and geography. To achieve these goals, 21 linear measurements were measured on the skulls of 509 specimens, coming from 111 different localities, across this species wide range. The specimens were then assigned into one of four broad geographic groups (≈ populations) based on their geographic proximity, and the overall and the pairwise differences in the 21 skull measurements among these groups were assessed. Specimens from Pakistan significantly differed from those belonging to the West Iran, East Iran, and India populations, which in turn did not significantly differ from each other. Pairwise bioclimatic and geographic distances between the localities explained a significant, yet small amount of variation in the measurements. Thus, while the Pakistani T. indica population was distinct in skull measurements, both climatic and non-climatic spatial factors seem not to account largely for its distinctiveness (from the other populations).

Late Pleistocene environments in the southern Zagros of Iran and their implications for human evolution

The Zagros Mountains represent a strategic geographic region near the junction of Africa, Europe, and Asia, and valleys within the mountain range likely correspond to migration corridors used by archaic and modern humans. Ghar-e Boof, a key archeological site in the southern Zagros, is located at an altitude of 905 m.a.s.l. in the Dasht-e Rostam region of the Fars Province, Iran. On the basis of lithic artifacts and radiocarbon and luminescence dating, the Late Pleistocene archeological record of the site spans from the Middle Paleolithic (MP) to the Late Epipaleolithic. Ghar-e Boof includes find horizons of the early Upper Paleolithic (UP) Rostamian dating to 42–35 ka cal. BP. These Rostamian-UP assemblages are typically attributed to modern humans. The high-resolution stratigraphy and microvertebrate record offer a unique opportunity for reconstructing the paleoenvironment of the southern part of the Zagros Mountains during the Late Pleistocene and contribute to a better understanding of long-term hominin settlement dynamics and cultural adaptations in this area. The current paper presents the first analysis of the microvertebrate remains recovered by the Tübingen-Iranian Stone Age Research Project (TISARP) team. All groups of small vertebrates, including fish, amphibians, squamate reptiles, birds, and micromammals, are present in the assemblage from Ghar-e Boof (NISP = 755). The key micromammal taxa used to reconstruct the paleoenvironment during the MP and UP include Libyan jird (Meriones cf. libycus), Vinogradov’s jird (Meriones vinogradovi), Indian gerbil (Tatera indica), Brandt’s hedgehog (Paraechinus cf. hypomelas), house mouse (Mus musculus), and mole vole (Ellobius sp.). Other taxa, such as amphibians (toad, Bufo/Bufotes sp.), fish (nase, Chondrostoma sp.), and squamate reptiles (agamids, lizards, Eastern Montpelier snake—Malpolon insignitus—and viper), also support the presence of an environment mainly characterized by warm, arid conditions with open, dry meadows, rocky terrain, and water sources close to the site throughout most of the sequence. During the shift from MP to UP, we record Afghan pika (Ochotona cf. rufescens), while all rodents, except very few remains of the Persian vole (Microtus cf. irani) and the Libyan jird (M. cf. lybicus) and some non-hibernating vertebrate species, are absent and reappear in later UP horizons. The presence of pikas could reflect a period of slightly colder and/or drier conditions. While the record from Ghar-e Boof is the only dataset from the southern Zagros, previous studies on microvertebrates from the central and northern Zagros show no clear change during the shift from the MP to the UP. Data from sediment cores and pollen analyses document numerous environmental and climatic fluctuations during the Late Pleistocene of the Zagros. The microvertebrate record from Ghar-e Boof improves our understanding of paleoenvironments during the Late Pleistocene and opens new opportunities to reconstruct the ecological conditions that helped to shape hominin settlement dynamics in the region.

Field efficacy of reduced active ingredient zinc phosphide formulation against rodents

A formulation of zinc phosphide with reduced active ingredient (40% concentrate) was evaluated for its rodenticidal activity in wheat, rice and sugarcane crops at farmer fields of Punjab, India. Comparison was made with the existing formulation (80% concentrate) and second generation anticoagulant bromadiolone (0.25% concentrate). Cereal based baits containing different doses of new (1.5, 2.0 and 2.5%) and existing zinc phosphide (2%) and bromadiolone (0.005%) were applied through burrow baiting where Bandicota bengalensis, Mus booduga, Millardia meltada and Tatera indica were the predominant rodents. The reduction in rodent activity was determined based on pre- and post-treatment bait census. Results revealed that 2% and 2.5% bait formulations of new zinc phosphide are as effective as the existing/ recommended zinc phosphide (2%) and bromadiolone (0.005%) bait formulations.

Reproductive Biology and Population Dynamics of Indian Gerbil Rat Tatera indica in Wheat Crop

Tatera indica, the Indian gerbil rat trapped during different growth stages of wheat crop, revealed that maximum mature gerbils (80-100%) were trapped during later growth stages (panicle initiation preharvest + lean period). While, 25 and 50% pregnant ones as well as 100 and 75% cyclic gerbils were collected during dough and preharvest stages, respectively. The weight of ovaries (13.00-19.00 mg/100 gbw), number and diameter of various follicles such as primordial (13.00-16.75; 19.57-19.98 μm), primary (6.50-7.33; 93.12-96.07 μm), secondary (2.75-3.67; 204.42-216.95 μm), pre-antral (2.75-3.50; 277.63-332.57 μm), antral (3.25-3.67; 474.44-499.98 μm), atretic (3.00-3.50; 211.49-247.33 μm) and corpus luteum (3.50- 5.50; 622.24-629.76 μm) were significantly more during later growth stages i.e. dough, preharvest stages and lean period. The sperm motility (89.50-89.67%), viability (92.50-92.67%) and count (119.67-131.75 millions/ml) was significantly more during dough and preharvest stages. The diameter of seminiferous tubules (203.68- 229.44 μm), number of spermatogonia (16.67-17.50), elongating spermatids (85.67-88.50) and elongated spermatids (81.00- 89.50) were significantly more during panicle initiation, dough and preharvest stages. Thus, control operations of T. indica should be done during tillering/panicle initiation stage before the initiation of their peak breeding activity during dough/ preharvest stages

Tatera indica

This datasheet on Tatera indica covers Identity, Distribution.

Impact of growth stages of rice crop on population dynamics and reproductive status of Tatera indica (HARDWICKE)

Tatera indica rodent pests were trapped during different growth stages of rice crop. The total trap index of gerbils and percentage of pregnant gerbils was observed to be maximum during tillering stage of rice crop. During transplanting-dough stage, all gerbils trapped were mature and weight of ovaries and testes was also maximum. The sperm parameters, diameter of mature ovarian follicles and seminiferous tubules were significantly higher during tillering, panicle initiation and dough stages of rice crop. The maximum reproductive activity of gerbils during tillering, panicle initiation and dough stage led to maximum population of these gerbils at pre-harvest stage. Thus, based on reproductive activity of T. indica, rodents control operations should be done before tillering stage of rice crop.

Correlation of soil temperature and moisture with burrow dimensions of Indian gerbil (Tatera indica)in loamy-sand soil of Punjab

Correlation of soil temperature and moisture with burrow dimensions of Indian gerbil (Tatera indica)in loamy-sand soil of Punjab

Diversity, Prevalence and Risk Assessment of Nematode Parasites in Tatera indica found in Punjab State

Background: Present study was aimed to record diversity, prevalence and risk assessment of nematode parasites in Indian gerbil, Tatera indica, a wild rodent species found in crop fields. Methods: Total 180 Indian gerbils (T. indica) were live trapped from crop fields of Ludhiana, Punjab between April, 2019 to March, 2020 and examined for the diversity and prevalence of nematode parasites in liver and gastrointestinal tract. Result: Only 33 (18.33%) gerbils were found infected with four nematodes species i.e. Nippostrongylus brasiliensis (39.40%), Calodium hepaticum (21.21%), Trichuris muris (21.21%) and Syphacia muris (18.18%). Eggs of N. brasiliensis, T. muris and S. muris were found in faecal samples. Pale yellow lesions on surface of liver and subsequent histopathology of infected liver indicated the presence of C. hepaticum eggs entrapped in parenchyma. Host age (χ2 = 8.78, P = 0.03) and season (χ2 = 9.21, P = 0.01) significantly affected the prevalence of N. brassiliensis and C. hepaticum, respectively. Shannon-Weiner index and Species Evenness of nematode parasites were maximum in monsoon season (1.04 and 0.94, respectively). Based on results proper rodent pest management is advised by integrated control measures at village level to prevent spread of diseases caused by them.

Observations on growth index and morphological characters of the Indian Gerbil, Tatera indica (Hardwicke) as an attempt to record intra-specific variations

Present study observed growth index and morphological characters of male and female Indian gerbil, Tatera indica (N = 64) live trapped from crop fields in Punjab, India as an attempt to record intraspecific variations. Growth index determined on the basis of increase in body weight and length of body parts recorded at weekly intervals upto nine weeks revealed a positive correlation between the two. No significant difference was found between growth index of male and female gerbils (body weight ≤150g and >150g). Tail length was slightly shorter (in ≤150g) or more (in >150g) than head+body length in females while, it was shorter than head+body length in males. Length of hind limbs was more in males, ears were oblong with fine hair on inner margin and the soles of hind paws were granulated. The study clearly depicted some differences in morphological and morphometric characteristics of T. indica suggesting further comprehensive studies to establish intra-specific variations.

A study on ectoparasites with special reference to chigger mites on rodents/shrews in scrub typhus endemic areas of Kerala, India

The main goal of this investigation was to record the ectoparasites living on rodents in scrub typhus endemic areas of Kerala state, India. Rodents captured alive using Sherman and wonder traps from four diverse habitations revealed, a total of 59 rodents/shrews constituted by 5 host species from families Muridae and Soricidae. In total, 1135 ectoparasites were collected on these rodents/shrews and were identified representing 23 species from 10 genera in 4 families Trombiculidae, Laelaptidae, Ixodidae and Pulicidae. Dominant insectivore species was Suncus murinus (57.6%). 42 (71.2%) rodents and shrews were found to be plagued with at least one of the 23 species of ectoparasite harvested. Mites belonging to the family Trombiculidae were the predominant ectoparasite species collected. Study revealed Tatera indica (35.5%) as the primary host harboring the chigger mites. Xenopsylla cheopis and Xenopsylla astia the flea species important vectors for the transmission of zoonotic diseases such as Leptotrombidium deliense, Schoengastiella ligula and Echinolaelaps echidninus were recorded. Twenty species of mites were reported for the first time in Kerala which add knowledge on the ectoparasites distribution.

Evaluation of Rodent Fauna of Rural Cutaneous Leishmaniasis Reservoir in East Azerbaijan Province of Iran During 2018-2019

Introduction: Leishmaniasis is one of the most important parasitic diseases that represents a serious health problem worldwide. This disease exists in three forms: cutaneous (rural, urban), visceral, and mucocutaneous. In the rural type, some rodents play the role of a reservoir. In our country, many people are infected with this disease every year. Cutaneous Leishmaniasis is now common in some parts of East Azerbaijan province. Considering that no comprehensive study on the general condition of cutaneous Leishmaniasis reservoirs in this province has been done so far, this research was very necessary. This study was conducted to investigate the fauna, distribution, and frequency of rodents in East Azerbaijan province from 2018 to 2019. Methods: This is a descriptive cross-sectional study. Cluster sampling was performed on rodents. Rodents were caught each week by 30 live traps from different parts of East Azerbaijan province and were determined in the laboratory after examining their morphological characteristics. In order to identify Leishmaniasis, 2 samples were prepared from each rodent ear on a laboratory slide and after fixation with methanol and staining by Giemsa method, they were examined by light microscope. Results: A total of 100 rodents were found in this study, which included 5 species of Rhombomys opimus, Meriones libycus, Mus musculus, Nesokia indica, and Tatera indica. In this study, a total of 3 rodents infected with Leishmania parasite were caught, 2 of which were from Meriones libycus from Azarshahr and Sarab counties and 1 from R. opimus from Kalibar. Conclusion: Infection of R. opimus and M. libycus species was identified in Azarshahr, Sarab, and Kalibar counties. These two species are the most important reservoirs of cutaneous leishmaniasis in Iran. It is suggested that rodents be controlled in areas where there are cases of disease and rodents have been infected with Leishmania parasite in order to control the disease.

Adoption of rodent pest management strategies by farmers of district Ludhiana, Punjab

The present study was conducted to assess adoption of rodent pest management strategies by farmers in District Ludhiana, Punjab during the year 2017-18. Farmers belonging to three villages, namely Barewaal Dogra (maintenance area), Kutbewaal Gujran (neglected area) and Ladiyan Kalan (survey area) having land holding ranging from 2.0-32.0 acres were selected. The pre-dominant rodent pest species in area under study was Bandicota bengalensis followed by Tatera indica, Millardia meltada and Mus boodguga. Education and training was provided to farmers belonging to maintenance and neglected villages whereas free rodenticide baits were distributed among farmers of maintenance village only. In survey village, no such activity was performed and kept as reference area. KAP survey (Knowledge Aptitude and Practice) of farmers before imparting education during paddy crop period revealed similar rodent control practices being used by farmers in all the three selected villages. Subsequent KAP survey during wheat crop period for impact assessment revealed the sustainability of education and training already imparted during paddy crop period. About 41-92% increase in farmers observing recommended rodent control practices during crop production was noticed. So timely education and free rodenticide bait distribution are important factors responsible for adoption and sustainability of rodent control strategies by the farmers. Farmer can save food grains (33.09 kg paddy/acre and 36.39 kg wheat/acre) with an economic benefit (Rs. 500.09-575.66/acre) and cost: benefit ratio of 1: 36 to 1: 39 by using education, training and free rodenticides which will help in food security.

Epidemiological survey on Cutaneous Leishmaniasis in southwestern Iran.

Cutaneous leishmaniasis (CL) is still a public health threat in many rural areas of Iran. It causes considerable morbidity among a huge number of people in the endemic areas. Khuzestan is considered as a CL focus in Iran and recently several cases have been reported from Shush County. The aim of the current study was to determine different aspects of CL epidemiology in this County. The study was conducted in four villages in the rural district of Shush County. In order to survey the scar and acute rate of the disease, 100 inhabitants were questioned in each village. In addition, to determine the reservoir host and vector of the disease, rodents were captured using Sherman traps, and sandflies were collected from around the rodent burrows using sticky paper traps. The scar and acute lesion rates were reported as 5.26 and 0.57% among inhabitants, respectively. Fifty-four rodents including Tatera indica (55.5%), Nesokia indica (33.3%), Mus musculus (9.3%) and Rattus norvegicus (1.9%) were captured and identified. Nested PCR showed 3 out of 54 rodents infected with Leishmania major. In total, 1122 sandflies were collected, and Leishmania major detected in Phlebotomus papatasi (4.35%), Sergentomyia dentata (23%), and Sergentomyia clydei (10%). Zoonotic cutaneous leishmaniasis due to L. major prevailed in this area. The common and the main vector was Ph. papatasi and, T. indica seems to be the main while N. indica as a secondary reservoir host of the disease in this area.

Growth and Breeding Biology of Female Indian Gerbil (Tatera Indica): Reproductive, Biochemical and Histological Evaluation

Average duration of pro-estrous, estrous, met-estrous and di-estrous stages in one oestrous cycle of female Indian gerbil, Tatera indica was found 0.61, 0.38, 0.62 and 1.37 days, respectively with total average duration of one cycle to be 2.99 days. Pairing of cyclic female gerbils with mature males resulted in 88% breeding success within gestation period of 21-24 days. Post-partum estrous was observed immediately after parturition in females not separated from males. Observations on onset of sexual maturity in female pups of seven different age groups (30, 45, 60, 75, 90, 105 and 120 days old) revealed significant increase in body weight and weights of ovary and uterus, plasma level of estradiol and activity of 3â-HSD in ovarian tissue with increasing age. Sexual maturity in female T. indica was attained at age of 3-4 months. It is therefore suggested to apply control measures before they reproduce and cause damage to crops.