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A better understanding of factors that influence the distribution and abundance of 3 species of rats that occur in Hawaii and cause extensive damage to sugarcane fields should lead to more effective control strategies, such as... more
A better understanding of factors that influence the distribution and abundance of 3 species of rats that occur in Hawaii and cause extensive damage to sugarcane fields should lead to more effective control strategies, such as species-specific use of rodenticides or habitat management that reduces pest populations. Thus, we estimated the relative abundances of the 3 species of rats at 4 Hawaiian sugarcane plantations that historically have received high levels of rodent damage, and quantified various environmental factors that might influence the distribution of these rodents. Overall, we captured 526 Norway rats (Rattus norvegicus), 335 Polynesian rats (R. exulans) and 139 blacks rats (R. rattus) during 11,200 trap-nights
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Research Interests: Mathematics, Statistics, Environmetrics, Nonparametric Statistics, Monte Carlo Simulation, and 13 moreEnvironmental Sciences, Sampling methods, Mathematical Sciences, Distance Sampling, Sample Size, Density Estimation, Spatial Pattern, Sample Size Determination, Simulation Study, Parametric Statistics, Monte Carlo Method, Confidence Interval, and Root mean square error
Research Interests: Biology, Predation, Transect, Urine, Field Study, and 4 moreNatural Environment, Feces, Mongoose, and Cage
Research Interests: Biology, Biological Sciences, Environmental Sciences, Wildlife, Litter, and 3 moreFecundity, Orchard, and nut
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ABSTRACT Rodenticides are a necessary part of successful large-scale rodent control programs, but poor bait acceptance by rats compromises the effectiveness of many baiting programs. Non-toxic bait markers are one approach for assessing... more
ABSTRACT Rodenticides are a necessary part of successful large-scale rodent control programs, but poor bait acceptance by rats compromises the effectiveness of many baiting programs. Non-toxic bait markers are one approach for assessing consumption and identifying the cause of failure. In single-feeding laboratory bioassays, we evaluated metallic flakes, Solvent Blue 36 oil-soluble dye, and tetracycline hydrochloride (THC) as bait markers for monitoring consumption of oat groats by captive black rats (Rattus rattus). We detected metallic flakes (0.3% [g/g] dietary concentration) in the gastrointestinal (GI) tracts of all 12 rats examined immediately following a single 24-hour feeding trial but in only 1 of 12 rats examined 48 hours later. We easily detected Solvent Blue 36 oil-soluble dye (0.1% to 0.5% [g/g]) in subcutaneous, abdominal, and genital fat of 7 of 8 rats 2 days after feeding, but found it in only 6 of 12 rats examined 5 days after feeding. Dye applied at 1.0% and 1.5% (g/g) persisted in all 8 rats inspected 5 days after feeding, but reduced consumption (P < 0.05) at these levels suggests that concentrations ≥1% are unpalatable to rats. Dietary concentrations of THC from 0.5% to 1.0% (g/g) produced a golden-yellow fluorescence under ultraviolet (UV) illumination on the incisors and growing points of the mandibles of all rats examined 3 and 14 days after feeding. Because THC had no apparent effect on consumption (P = 0.28), it offers a reliable means of detecting consumption by black rats and thus, of determining whether poor results with rodenticides are due to poor bait acceptance.
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... bioassays with pine voles (Microtus pinetorum), moist ZP0 Rodent Bait AG pellets were as acceptable and effective as dry pellets (Merson & Byers, 1985 ... Heather Krupa provided statistical advice, Rodney Medeiros helped... more
... bioassays with pine voles (Microtus pinetorum), moist ZP0 Rodent Bait AG pellets were as acceptable and effective as dry pellets (Merson & Byers, 1985 ... Heather Krupa provided statistical advice, Rodney Medeiros helped collect bait samples, and Yusuf Tamimi analyzed soil pH ...
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... Crop Protection 1993 Volume 12 Number 4 247 Rat trapping in macadamia orchards: ME Tobin et al. ... (1988) SAS STAT User's Guide, Release 6.03 Fellows, DP, Sugihara, RT and Pank, LF (1978) Evaluation Edition, SAS Institute... more
... Crop Protection 1993 Volume 12 Number 4 247 Rat trapping in macadamia orchards: ME Tobin et al. ... (1988) SAS STAT User's Guide, Release 6.03 Fellows, DP, Sugihara, RT and Pank, LF (1978) Evaluation Edition, SAS Institute Inc., Cary, NC, 1028 pp of treatment techniques ...
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Abstract. We conducted an extensive simulation study to compare the performance of a large group of plotless density estimators (PDEs) to obtain clarification of their relative performance in a diversity of sampling situations. The PDEs... more
Abstract. We conducted an extensive simulation study to compare the performance of a large group of plotless density estimators (PDEs) to obtain clarification of their relative performance in a diversity of sampling situations. The PDEs studied included well-known ones from the literature plus some extensions and modifications introduced here. The
ll?hl-?1V4lv7 $17.011+0.00 Bait placement and acceptance by rats in
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We determined seasonal patterns of fecundity and diet of roof rats (Rattus rattus) snap-trapped in an orchard of macadamias (Macadamia integrifolia), and assessed the implications for controlling rat damage to macadamia nuts. In all, 903... more
We determined seasonal patterns of fecundity and diet of roof rats (Rattus rattus) snap-trapped in an orchard of macadamias (Macadamia integrifolia), and assessed the implications for controlling rat damage to macadamia nuts. In all, 903 males, 756 females, and 16 rats of unidentified sex were captured between June 1990 and April 1991. Sex ratios varied from 1 : 1 only during August, when males outnumbered females (P < 0.05). Subadult rats were present throughout the study and comprised 31% of captures. Adult male roof rats were in reproductive condition throughout the year, and females bore young during every month of the study. Average monthly pregnancy rates varied from 8% to 54% and were highest in April. Mean prenatal litter size ranged from 3.0 to 6.5 among months. Macadamia nut was the dominant food item throughout the study, and was present in all 199 stomachs inspected, with a mean relative frequency of 85%. Insect fragments, primarily lepidopteran larvae, occurred in 66...
Research Interests: Biology, Biological Sciences, Environmental Sciences, Wildlife, Litter, and 3 moreFecundity, Orchard, and nut
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... For the test with HGP oats, we broadcast untreated oat groats in 1 section of each field 7 days before we applied zinc phosphide oats to the same sections. ... Because past studies have indicated a low recapture rate of rats with live... more
... For the test with HGP oats, we broadcast untreated oat groats in 1 section of each field 7 days before we applied zinc phosphide oats to the same sections. ... Because past studies have indicated a low recapture rate of rats with live traps (Lindsey et al. 1973, Sugihara et al. ...
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A better understanding of factors that influence the distribution and abundance of 3 species of rats that occur in Hawaii and cause extensive damage to sugarcane fields should lead to more effective control strategies, such as... more
A better understanding of factors that influence the distribution and abundance of 3 species of rats that occur in Hawaii and cause extensive damage to sugarcane fields should lead to more effective control strategies, such as species-specific use of rodenticides or habitat management that reduces pest populations. Thus, we estimated the relative abundances of the 3 species of rats at 4 Hawaiian sugarcane plantations that historically have received high levels of rodent damage, and quantified various environmental factors that might influence the distribution of these rodents. Overall, we captured 526 Norway rats (Rattus norvegicus), 335 Polynesian rats (R. exulans) and 139 blacks rats (R. rattus) during 11,200 trap-nights
Research Interests:
ABSTRACT Rodenticides are a necessary part of successful large-scale rodent control programs, but poor bait acceptance by rats compromises the effectiveness of many baiting programs. Non-toxic bait markers are one approach for assessing... more
ABSTRACT Rodenticides are a necessary part of successful large-scale rodent control programs, but poor bait acceptance by rats compromises the effectiveness of many baiting programs. Non-toxic bait markers are one approach for assessing consumption and identifying the cause of failure. In single-feeding laboratory bioassays, we evaluated metallic flakes, Solvent Blue 36 oil-soluble dye, and tetracycline hydrochloride (THC) as bait markers for monitoring consumption of oat groats by captive black rats (Rattus rattus). We detected metallic flakes (0.3% [g/g] dietary concentration) in the gastrointestinal (GI) tracts of all 12 rats examined immediately following a single 24-hour feeding trial but in only 1 of 12 rats examined 48 hours later. We easily detected Solvent Blue 36 oil-soluble dye (0.1% to 0.5% [g/g]) in subcutaneous, abdominal, and genital fat of 7 of 8 rats 2 days after feeding, but found it in only 6 of 12 rats examined 5 days after feeding. Dye applied at 1.0% and 1.5% (g/g) persisted in all 8 rats inspected 5 days after feeding, but reduced consumption (P &lt; 0.05) at these levels suggests that concentrations ≥1% are unpalatable to rats. Dietary concentrations of THC from 0.5% to 1.0% (g/g) produced a golden-yellow fluorescence under ultraviolet (UV) illumination on the incisors and growing points of the mandibles of all rats examined 3 and 14 days after feeding. Because THC had no apparent effect on consumption (P = 0.28), it offers a reliable means of detecting consumption by black rats and thus, of determining whether poor results with rodenticides are due to poor bait acceptance.
Research Interests:
Research Interests:
Research Interests:
... bioassays with pine voles (Microtus pinetorum), moist ZP0 Rodent Bait AG pellets were as acceptable and effective as dry pellets (Merson &amp;amp; Byers, 1985 ... Heather Krupa provided statistical advice, Rodney Medeiros helped... more
... bioassays with pine voles (Microtus pinetorum), moist ZP0 Rodent Bait AG pellets were as acceptable and effective as dry pellets (Merson &amp;amp; Byers, 1985 ... Heather Krupa provided statistical advice, Rodney Medeiros helped collect bait samples, and Yusuf Tamimi analyzed soil pH ...
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... Rats were captured, maintained and tested according to approved US Department of Agriculture protocols and animal welfare standards. REFERENCES Aggeler, PM, O&amp;amp;amp;amp;#x27;Reilly, RA, Leong, L. Kowitz, PE (1967). ...... more
... Rats were captured, maintained and tested according to approved US Department of Agriculture protocols and animal welfare standards. REFERENCES Aggeler, PM, O&amp;amp;amp;amp;#x27;Reilly, RA, Leong, L. Kowitz, PE (1967). ... Status of the darkrumped petrel on Maui, 1972. Elepaio, 34,1112. ...
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Rat lungworm (Angiostrongylus cantonensis) is a neurotropic nematode, and the leading cause of eosinophilic meningitis worldwide. The parasite is usually contracted through ingestion of infected gastropods, often hidden in raw or... more
Rat lungworm (Angiostrongylus cantonensis) is a neurotropic nematode, and the leading cause of eosinophilic meningitis worldwide. The parasite is usually contracted through ingestion of infected gastropods, often hidden in raw or partially cooked produce. Pharmaceutical grade pyrantel pamoate was evaluated as a post-exposure prophylactic against A. cantonensis. Pyrantel pamoate is readily available over-the-counter in most pharmacies in the USA and possesses anthelmintic activity exclusive to the gastrointestinal tract (GIT). Administering pyrantel pamoate immediately after exposure should theoretically paralyze the larvae in the GIT, causing the larvae to be expelled via peristalsis without entering the systemic circulation. In this study, pyrantel pamoate (11 mg/kg) was orally administered to experimentally infected rats at 0, 2-, 4-, 6-, or 8-h post-infection. The rats were euthanized six weeks post-infection, and worm burden was evaluated from the heart-lung complex. This is the first in vivo study to evaluate its efficacy against A. cantonensis. This study demonstrates that pyrantel pamoate can significantly reduce worm burden by 53–72% (P = 0.004), and thus likely reduce the severity of infection that is known to be associated with worm burden. This paralyzing effect of pyrantel pamoate on the parasite may also be beneficial for delaying the establishment of infection until a more suitable anthelmintic such as albendazole is made available to the patient.
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... Crop Protection 1993 Volume 12 Number 4 247 Rat trapping in macadamia orchards: ME Tobin et al. ... (1988) SAS STAT User&amp;#39;s Guide, Release 6.03 Fellows, DP, Sugihara, RT and Pank, LF (1978) Evaluation Edition, SAS Institute... more
... Crop Protection 1993 Volume 12 Number 4 247 Rat trapping in macadamia orchards: ME Tobin et al. ... (1988) SAS STAT User&amp;#39;s Guide, Release 6.03 Fellows, DP, Sugihara, RT and Pank, LF (1978) Evaluation Edition, SAS Institute Inc., Cary, NC, 1028 pp of treatment techniques ...
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Chemical repellents derived from predators might offer more effective and longer lasting protection from vertebrate depredations than current damage control measures. Thus, we conducted laboratory and field studies to evaluate the... more
Chemical repellents derived from predators might offer more effective and longer lasting protection from vertebrate depredations than current damage control measures. Thus, we conducted laboratory and field studies to evaluate the repellency of mongoose feces and urine to black rats (Rattus rattus) and Polynesian rats (R. exulans ) . We exposed captive wild rats to water, butyric acid, mongoose (Herpestes auropunctatus) feces, or mongoose urine in a 150- x 60- x 120-cm partitioned arena and recorded their behavior with a video camera. None of the test substances had any apparent effect (P\u3e 0.05) on behavior or the percentage of observations spent (1) in the transfer cage, (2) in tunnels, (3) on the side of the arena with the treatment, (4) in, on, or near the tunnel with the treatment, or (5) in the tunnel with the treatment. Nor did we observe any effect on latency until rats emerged from the transfer cage or entered the treated tunnel or time spent in the treated tunnel during ...
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Brown tree snakes (Boiga irregularis, BTS), inadvertently introduced to the island of Guam shortly after World War II, have had catastrophic effects on the native fauna of this U.S. territory. We used radio-telemetry to monitor daytime... more
Brown tree snakes (Boiga irregularis, BTS), inadvertently introduced to the island of Guam shortly after World War II, have had catastrophic effects on the native fauna of this U.S. territory. We used radio-telemetry to monitor daytime refugia and nightly movements of 60 BTS (30 during each of two seasonal periods) to determine the extent of nightly, weekly, and monthly movements. Eighty-three percent of subadult daytime sightings were in trees, compared to only 49% of adult daytime sightings. Most measures of movement did not vary with seasonal period, sex, or age class. BTS moved an average of 64 m (Range: 9-259 m) between successive daily refugia. Mean total cumulative distance traveled between successive locations from one afternoon to the next was 238 m during January-March and 182 m during May- July. However, over the course of each seasonal period (60-70 d), most snakes concentrated their activity within core areas. During each of the two seasonal periods, snakes were located...
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A non-toxic liquid fertility control bait for rats has recently become commercially available (ContraPest from SenesTech, Inc.). This product contains two chemicals, both of which impair spermatogenesis in male and reduce ovulations in... more
A non-toxic liquid fertility control bait for rats has recently become commercially available (ContraPest from SenesTech, Inc.). This product contains two chemicals, both of which impair spermatogenesis in male and reduce ovulations in female rats. We tested the efficacy of this bait in wild-caught adult black rats from the island of Hawai’i in a short-term laboratory trial. A control group (n = 25) was offered placebo bait and the treatment group (n = 25) was offered fertility control bait, both ad libitum, during a 15-day introduction period and during the first of four breeding rounds, for a total of 58 days of exposure. After treatment, all rats were provided placebo bait for the remainder of the study and randomly paired with mates from within their treatment groups for two additional breeding cycles. Treatment and control groups comprised 10 breeding pairs each, with random re-pairings between breeding rounds. The treatment group produced no litters during the first and second...
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Research Interests: Zoology, Veterinary Medicine, Population Biology, Biology, Life Sciences, and 12 moreEnvironment and natural resources conservation, Regulation, Invasive Species, Environmental Sciences, Pesticide, PEST, Animal Sciences, Veterinary Infectious Diseases, Mongoose, Management of Biological Invasions (Invasive Exotic Plants), Humaneness, and Regulatory Requirements
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Angiostrongylus cantonensis is a pathogenic nematode and the cause of neuroangiostrongyliasis, an eosinophilic meningitis more commonly known as rat lungworm disease. Transmission is thought to be primarily due to ingestion of infective... more
Angiostrongylus cantonensis is a pathogenic nematode and the cause of neuroangiostrongyliasis, an eosinophilic meningitis more commonly known as rat lungworm disease. Transmission is thought to be primarily due to ingestion of infective third stage larvae (L3) in gastropods, on produce, or in contaminated water. The gold standard to determine the effects of physical and chemical treatments on the infectivity of A. cantonensis L3 larvae is to infect rodents with treated L3 larvae and monitor for infection, but animal studies are laborious and expensive and also raise ethical concerns. This study demonstrates propidium iodide (PI) to be a reliable marker of parasite death and loss of infective potential without adversely affecting the development and future reproduction of live A. cantonensis larvae. PI staining allows evaluation of the efficacy of test substances in vitro, an improvement upon the use of lack of motility as an indicator of death. Some potential applications of this as...