Rattus Argentiventer Research Articles

RANGING AND NESTING BEHAVIOR OF THE RICEFIELD RAT RATTUS ARGENTIVENTER (RODENTIA: MURIDAE) IN WEST JAVA, INDONESIA

Abstract Movements, ranging behavior, and social organization of the ricefield rat (Rattus argentiventer) were studied by radiotracking in a rice field in West Java, Indonesia. Home ranges were estimated by the minimum convex polygon method and were found to be significantly larger in the nonbreeding season than in the breeding season. During the breeding season, males had larger home ranges than did females (3.20–3.24 ha, as compared to 2.51–2.34 ha), but no sexual differences were found in the nonbreeding season. Overlap between home ranges occurred during the breeding season, especially for males. During the nonbreeding season, rats appeared to be nomadic, and nests seemed to be distributed at random within ranges. Males and females were never found to share nests during the nonbreeding season. Habitat use was investigated by recording percentage occupancy of the following habitat elements: rice paddies, banks, and vegetation. Totals of 63% and 60% of radiofixes were made in paddies during the rainy an...

PENGGUNAAN PERANGKAP UNTUK PENGENDALIAN HAMA TIKUS SAWAH (RATTUS RATTUS ARGENTIVENTER)

The use of traps to control lowland rats. The lowland rat (Rattus rattus argentiventer ) is one of the importance pests of rice in Indonesia. The rat may cause serious damage on rice and other crops. This study was aimed to determine the affectivity of rat trappings. Traps were set in Pekalongan Central Lampung, from October to December 2002. The treatments were arranged in a factorial experiment in randomized complete block design. The first factor was the type of traps (bamboo trap and wired “bubu” trap) while the second factor was the location of traps (rice field, swamp, tertiary irrigation canal, and rice plot borders). The catches show that there were no interaction between the trap type and trap location. In addition, more rats were caught in bamboo than those in wired “bubu” trap. The highest number of rat catches was from the swamp area.

Rates of population increase in the ricefield rat (Rattus argentiventer) as a function of food supply: an enclosure study in Jatisari, West Java

AbstractThe relationship between the population dynamics of ricefield rats Rattus argentiventer and their food supply, rice plants, was investigated in an enclosure in Jatisari, West Java. The density of the rat population fluctuated greatly throughout the year depending on the growth stages of the rice plants. A model illustrating the responses of the rat population to the growth stages of the rice plants is described. The population increased following periods when high‐quality rice plants were available, and decreased following periods when only low‐quality rice plants were available. The highest rate of increase (r) over a 2‐week period was observed during the dry season of 1989 (r=1.77). The lowest rate of increase over 2 weeks was observed during the rainy season of 1989–90 (r=−0.59). The maximum rate of increase for the ricefield rat in the numerical response function was 1.183 month−1, and the best estimate for the numerical response function was robs=−3.890±5.043(1−e−0.026V).

Movements of the ricefield rat, Rattus argentiventer, near a trap-barrier system in rice crops in West Java, Indonesia

The movements of the ricefield rats ( Rattus argentiventer ) near a trap-barrier system (TBS) were assessed in lowland flood-irrigated rice crops in West Java, Indonesia, to test the hypothesis that a TBS with a 'trap-crop' modifies the movements of rats within 200 m from the trap-crop. The home range use and locations of rat burrows were assessed using radiotelemetry at two sites, one with a TBS with trap-crop (Treatment site, the crop inside the fence was planted 3 weeks earlier than the surrounding crop) and the other with a TBS without trap-crop (Control site, the crop inside the fence was planted at the same time as the surrounding crop). Each TBS was a 50 2 50 m plastic fence with eight multiple-capture rat traps set at the base. More than 700 rats were caught in the TBS with trap-crop, whereas only 10 rats were caught in the TBS without trap-crop. The home range size of females was significantly smaller at the Treatment site (0.96 ha) than the Control site (2.99 ha), but there was no difference for males. Seventy-eight per cent of rats caught in the TBS and fitted with radiocollars had their daytime burrow locations within 200 m of the TBS. We could not determine if the rats caught in the TBS were residents or transients according to demographic parameters. Our results support the hypothesis that a TBS with a trap-crop protects the surrounding rice crop out to a distance of at least 200 m.

Taxonomic status of the ricefield rat Rattus argentiventer (Robinson and Kloss, 1916) (Rodentia) from Thailand, Malaysia and Indonesia based on morphological variation

– Comparison of cranial and external characters of 212 rice field rats Rattus argentiventer (Robinson and Kloss 1916), by univariate and multivariate statistical analyses, was carried out on specimens from Thailand, Malaysia, and Indonesia (Sumatra, Kalimantan, Java, Bali, Lesser Sunda, Sulawesi and Irian Jaya).

C02 フィリピン・ルソン島の植栽林におけるクマネズミの行動

C02 フィリピン・ルソン島の植栽林におけるクマネズミの行動

Comparison of different sizes of physical barriers for controlling the impact of the rice field rat, Rattus argentiventer, in rice crops in Indonesia

The effectiveness of different size trap-barrier systems (TBS)—50×50 m, 30×30 m and 20×20 m—was assessed for managing the impact of pre-harvest damage by the rice field rat, Rattus argentiventer, on dry season rice crops in West Java. Each TBS had a crop planted inside the barrier that was 3 weeks earlier than the surrounding crop. 2635 rats were captured in six TBS, with 58% of rats caught from maximum tillering to booting. More rats were caught in the larger TBS, yet the levels of rat damage and yield loss in nearby crops were similar for the different sizes of TBS. The mean yields from the crops surrounding the TBS sites compared to the control sites were 4.72 t/ha versus 4.00 t/ha. The benefit–cost ratios were: 14:1 for the 50×50 m TBS; 10:1 for the 30×30 m TBS; 24:1 for the 20×20 m TBS. We recommend that one TBS of minimum size 20 m×20 m is required every 10 ha and that the technology be adopted at the village level as part of an integrated ecologically based approach to rodent management.

Demographics and burrow use of rice-field rats in Indonesia

Author(s): Nolte, Dale L.; Jacob, Jens; Sudarmaji; Hartono, R.; Herawati, N. A.; Anggara, A. W. | Abstract: Foraging by rice-field rats (Rattus argentiventer) can significantly reduce rice harvest. Rat populations are cyclic responding to season and crop maturity. Rat location also reflects the crop cycle. A study conducted near Sukamandi, Indonesia described rice-field rat burrow systems and patterns of use, and assessed demographics of rice-field rats found in burrows adjacent to rice fields. Burrows ranged from simple short tunnels to complex systems. Most simple systems consisted of a straight tunnel approximately 75 cm long. Mean tunnel length of more complex systems was approximately 300 cm, but a few contained tunnels up to 700 cm. Burrow systems had between 1 and 5 entrances, with 0 to 8 choice-points within the system. A choice-point was defined as any place within the system where the animal could choose a different path (e.g., Y in the tunnel, nest). Number of chambers within systems also varied, ranging from none to six. There was no correlation between rat activity within a system, measured by the closed-hole method, and complexity of the system. Long-term monitoring suggested both male and female rats occupied burrow systems along rice banks, except relatively short periods during spring (March, April) and early fall (September) when burrows were used almost exclusively by females. These periods appear to correlate when high numbers of female rats are gestating and lactating.

Ecologically-based management of pest rodents in rice-based agro-ecosystems in southeast Asia

About 70% of the current energy intake of the human population in southeast Asia is met by rice. Rats, especially the ricefield rat, Rattus argentiventer, cause significant pre- and post-harvest losses in rice-based agro-ecosystems of southeast Asia and therefore require appropriate management. Current management practices focus on culling animals when populations are high and after significant damage has already occurred. The use of legal and illegal poisons poses a considerable threat to non-target species and humans. This is of particular concern in regions where rats are often consumed by humans to provide an important protein supplement to their diet. During the last seven years, CSIRO’s rodent research group has tested and refined several methods aimed at decreasing pre-harvest rodent damage in cooperation with the Indonesian Research Institute for Rice and the Vietnamese National Institute for Plant Protection. These methods include exclusion of rats by fencing and physical control by trap-barrier systems with lure crops. The effects of these technologies were investigated regarding the regulation of rat numbers (physical control), damage (exclusion, physical control) and yield (physical control). The results are promising, indicating yield increase, of up to 20% in some cases. Integration of these methods with improved field sanitation, crop synchronisation and more efficient timing of other physical methods of control should result in pronounced increases in yield and improved cost effectiveness. Our approach is contingent on a strong understanding of the ecology of specific rodent pests. Measures of success besides decrease in rat numbers and damage are an increase in farmers’ net income through yield increase and a decrease in the use of chemicals. Pros and cons of these methods in different economic and cultural environments are discussed.

Habitat use and movements of the rice-field rat, Rattus argentiventer, in West Java, Indonesia

Les mouvements, l'utilisation de l'habitat et la taille du territoire habituel du rat des rizieres, Rattus argentiventer ont ete determines dans les rizieres des plaines de l'ouest de Java en Indonesie. Nous avons capture 36 rats (20 mâles et 16 femelles) a 2 endroits pendant 5 semaines de riziculture en saison seche (juin-juillet 1997) et leurs deplacements ont ete suivis au moyen des collier radio-emetteurs. Pendant cette periode, les rizieres ont pousse jusqu'a la floraison. La taille minimale du domaine habituel des individus des deux sexes a ete determinee par la methode des polygones convexes (3.01 ± 0.9 ha pour les mâles et 1.97 ± 0.5 ha pour les femelles). La difference entre les deux estimations de taille des domaines n'est pas importante (P < 0.05). Les mâles se sont deplaces plus loin que les femelles en regle generale, et les individus des deux sexes se sont deplaces plus loin en Juin qu'en Juillet. La distance moyenne entre deux localisations pour les rats etait de 75 metre environ, mais il y avait aussi certains rats qui ont ete jusqu'a 480 metres. En juin les rats se trouvaient a l'interieur des terriers, la plupart (84%) dans les remblais au bord des rizieres. En juillet par contre, les rats se trouvaient plus souvent dans les rizieres (59%), ce qui coincide avec la densite de vegetation du riz pendant les premiers stades de sa croissance.

Ecologically-based rodent management integrating new developments in biotechnology

Author(s): Singleton, Grant R. | Abstract: Chemical control is currently the primary driver of Integrated Pest Management (IPM) for rodents. This generally provides effective control in the short term, regardless of the rodent species. However, governments are concerned about the use of chemicals, especially when they are striving to provide clean and green food products for their domestic and export markets. In developing countries, the challenge is first to develop a good understanding of the ecology of the pest species and then assess the efficacy of using traditional and new methods of rodent control. This will enable adoption of management actions that are more environmentally sound and sustainable (environmentally and culturally). This approach is termed Ecologically-Based Rodent Management (EBRM). How EBRM operates in an operational sense is presented for two rather different geographic regions, research approaches and strategies for management. The first research approach is ecologically-based management of rodent pests in rice fields of Southeast Asia. As an indication of their impact, rodents are the greatest agricultural problem in Indonesia causing annual losses to rice production of 17%. I report on the development of a rodent management project in West Java, Indonesia. The initial phase of the research was developing an understanding of the population ecology and habitat use of the main pest species, the rice-field rat (Rattus argentiventer). These findings have been combined with local knowledge (of rodents and farming systems) to develop an ecologically-based management strategy of the rice-field rat at a village-level. The second research approach is biological control of house mouse populations in Australia. Mouse populations erupt into plague proportions in cereal-growing regions causing substantial economic and social stress to rural communities. We are examining whether mouse populations can be managed with fertility control either by a non-infectious agent delivered in an oral bait, or by infectious viruses as carriers of an infertility agent. Although the focus is often on the biotechnology aspect of this research, it is knowledge of the population ecology of mice and the epidemiology of mouse cytomegalovirus in field populations that will provide the critical context for this management strategy.

A new ecology for scrub typhus associated with a focus of antibiotic resistance in rice farmers in Thailand.

Following the documentation of chloramphenicol-resistant and doxycycline-resistant strains of Orientia tsutsugamushi (Hyashi) in northern Thailand, we conducted ecological and epidemiological studies near the houses of patients hospitalized with antibiotic-resistant infections. New associations between chiggers, rodents, and O. tsutsugamushi in active rice agriculture areas, an ecological habitat not described previously, are reported. Rattus rattus (L.) was the most common species (representing 85.8% of the 1,433 rodents processed), followed by Rattus losea (Swinhoe) (9.4%), Bandicota indica (Bechstein) (3.6%), and Rattus argentiventer (Robinson and Kloss) (1.3%). O. tsutsugamushi was isolated from 30% of the R. rattus and R. losea, 29% of the B. indica, and 33% of the R. argentiventer collected. Mean minimum infection rates were 0.03 in Leptotrombidium chiangraiensis Tanskul & Linthicum, a new species of chigger, and 0.002 in Leptotrombidium imphalum (Vercammen-Grandjean & Langston), a chigger species not previously associated with scrub typhus transmission. Efficient vertical and horizontal transmission of O. tsutsugamushi by L. chiangraiensis and L. imphalum was demonstrated. During a 19-mo period from October 1993 to April 1995, the overall prevalence of human IgM and IgG antibody to O. tsutsugamushi was 25.5 and 47.3%, respectively. L. chiangraiensis and L. imphalum are incriminated as vectors of O. tsutsugamushi in a rice field habitat associated with a focus of antibiotic resistance.

An experimental field study to evaluate a trap-barrier system and fumigation for controlling the rice field rat, Rattus argentiventer, in rice crops in West Java

The effectiveness of a trap-barrier system (TBS), which enclosed a crop planted 2–3 weeks early (trap-crop), and fumigation (sulfur dioxide) was assessed for managing pre-harvest damage by the rice field rat, Rattus argentiventer, to rice crops in West Java, Indonesia. The TBS was a 50 × 50 m plastic fence with live-multiple-capture traps inserted intermittently at its base. Damage to tillers and yield loss were assessed within the trap-crop and at 5, 50, 100, 150 and 200 m from the TBS. Two crops were monitored: dry season crop when rat densities were high and 20–55% of rice tillers were cut by rats; wet season crop when rat densities were low and 0–4% of rice tillers were cut. Over the two crops, rats caused a 20% annual loss in potential rice production. The benefit—cost ratios for using a TBS were in the range of 20:1 to 7:1 for the dry season and 7:1 to 2:1 for the wet season. Fumigation was not effective in reducing rat losses. Damage assessment provided a phenology of rat damage for the two crops but, unlike the yield data, differences were not significant between treatments. The benefits of the TBS need to be weighed against high labour input, initial cost, logistics of growing a trap-crop, and whether the technology can be transferred to growers. Research on how rats respond to a TBS-plus-trap-crop is required before it can be recommended to manage rats.

Seasonal changes in the population density and reproduction of the ricefield rat, Rattus argentiventer (Rodentia: Muridae), in West Java

Article Seasonal changes in the population density and reproduction of the ricefield rat, Rattus argentiventer (Rodentia: Muridae), in West Java was published on January 1, 1998 in the journal Mammalia (volume 62, issue 2).

A new species of Leptotrombidium (Acari:Trombiculidae) collected in active rice fields in northern Thailand.

Leptotrombidium (Leptotrombidium) chiangraiensis Tanskul & Linthicum is described and illustrated as new from specimens collected from the rodents Rattus rattus (L., 1758), Rattus argentiventer (Robinson & Kloss, 1916), Rattus losea (Swinhoe, 1870), and Bandicota indica (Bechstein, 1800) in Chiangrai Province northern Thailand. The new species was collected in active rice fields and adjacent fruit plantation areas. The etiological agent of scrub typhus, Orientia (formerly Rickettsia) tsutsugamushi (Hayashi), has been isolated from patients who live and work in the same habitat where L. chiangraiensis is the predominant Leptotrombidium species.

Liquid baits for rodent control: A comparison of wild Norway versus wild ricefield rat response to glucose plus saccharin solutions

A series of two-bottle tests were conducted with wild Norway ( Rattus norvegicus) and wild ricefield ( Rattus rattus mindanensis) rats to assess liquid bait consumption levels. Glucose, a natural sugar, and saccharin, an artificial sweetening agent, were tested against a combination of the sweeteners in water solution with each rat species. Water baseline data indicated that ricefield rats drank relatively more water per day. No species differences, however, were found for consumption levels of 3.0% glucose or for 0.125% saccharin when fluid intake levels were adjusted for mean body weight differences between species using metabolic size data transformations to yield relative consumption levels. A species difference was shown for relative consumption of the mixture of 3.0% glucose plus 0.125% saccharin in water solution with either sweetener as the alternate choice. Ricefield rats showed a two-fold increase in relative consumption of the mixture compared with solutions of either sweetener alone. Norway rats, in contrast, showed a synergistic six-fold increase in relative consumption of the mixture compared with solutions of either component alone. A second series of two-bottle choice tests with new groups of rats showed that both saccharin and glucose solution consumption levels were similar in the two species. The lack of glucose plus saccharin synergism in the ricefield rat response was found to be related to less preference by ricefield rats for glucose when paired with saccharin solution compared to the Norway rat preference pattern. Implications on the potential application of these results to the control of the two species using liquid bait stations are discussed and summarized.

Self-Anointing Behavior in the Rice-Field Rat, Rattus rattoides

The rice-field rat, Rattus rattoides , displayed self-anointing behavior when anal-gland secretion of a weasel, Mustela sibirica , was encountered. This behavior was not observed when the rats encountered water and the urine from a red fox, Vulpes vulpes . Juvenile rats born in the laboratory without any experience with weasels also displayed the behavior upon encountering the secretions. The self-anointing behavior in the rat is not sex-specific, nor is it age-specific.

Molinacuaria indonesiensis n. sp. (Nematoda, Acuarioidea) from Rattus argentiventer in Indonesia

Molinacuaria indonesiensis n. sp. from the stomach of Rattus argentiventer, the ricefield rat, in Sukamandi, Java, Indonesia is described and figured from the examination of seven males and three females. The species is separated from the three other species of the genus, namely, M. bendelli (Adams & Gibson, 1969) Wong & Lankester, 1985, M. acholonui (Schmidt & Kuntz, 1972) Wong & Lankester, 1985 and M. gallinulae (Wang, 1966) Wong & Lankester, 1985. The species is characterised by (i) the larger body measurements, (ii) the presence of a fold rather than a deep groove separating the anterior cephalic region and the ptilina which form four distinct shields, (iii) the morphology of the four ptilina, each one being tripartite with a pointed middle section twice as long at the two lateral sections (iv) the number of papillae on the posterior end of the male (two pairs pre-cloacal, four pairs post-cloacal), (v) the morphology of the left spicule, and (vi) the female tail being straight with a terminal knob.

Tikusnema javaense n. gen., n. sp. (Nematoda: Acuarioidea) and Other Nematodes from Rattus argentiventer Collected in West Java, Indonesia

Nematodes collected from the ricefield rat, Rattus argentiventer (Rodentia: Muridae), in Pusakanagara and Sukamandi, West Java, Indonesia, are reported. Tikusnema javaense n. gen., n. sp. (Nematoda:Acuariidae:Seuratiinae) is described from the small intestine. This new genus is distinguished readily from other genera of the subfamily Seuratiinae in having 4 strongly protruded cuticular leaves in the posterior cephalic portion and in having a pair of prominent cuticular ornamentations posterior to deirids. Besides T. javaense, Eucoleus bacillatus, Strongyloides ratti, Nippostrongylus brasiliensis, Syphacia muris, and Physaloptera sp. were detected.

Field trials of warfarin and brodifacoum wax block baits for the control of the rice field rat,Rattus argentiventerin peninsular Malaysia∗

Abstract Replicated trials, in which 0.05% warfarin and 0.005% brodifacoum were used to control rice field rats, are described. In the first trial, 15 g wax blocks containing the poisons were applied, in 20–24 ha rice field plots, once a week for four weeks or twice a week for four weeks or once a week for 8 weeks. In the second trial, 5 g wax blocks were applied once a week for four weeks. In both trials baiting commenced at the time of transplanting, and the effectiveness of treatments was measured by mortality estimates, derived from pre‐ and post‐treatment census baiting in treated and reference plots and by damage reduction in post‐treatment damage assessments. Both poisons were equally effective when applied as 15 g blocks giving, on average, between 81% and 82% control, but gave significantly better control (87%) when applied twice a week rather than once (79%). However, when 5 g blocks were used, the more toxic poison, brodifacoum, gave 80% control compared with only 56% with warfarin. Tiller cutt...