Evidence of predation on a young tuatara,Sphenodon punctatus,by kiore,Rattus exulans,on Lady Alice Island

Abstract

Wounds on a juvenile tuatara discovered dead on Lady Alice Island, Chickens group, Hauraki Gulf, appear to have been inflicted by kiore. Flesh was stripped from the right abdominal wall of the tuatara exposing its ribs and liver, and part of its tail and eight digits were missing.     

The population ecology of Rattus exulans on Tiritiri Matangi Island,and a model of comparative population dynamics in New Zealand

Abstract

On Tiritiri, a small predator-free island in northern New Zealand, kiore (Rattus exulans) were live and snap trapped in grassland and forest. In both habitats, kiore abundance peaked in late summer/autumn. The increase followed a 3 month breeding season during which females produced two to three litters, each averaging 7 young. During the population decline in autumn and winter, animals lost weight. Few bred in the breeding season of their birth and none lived to breed in a second breeding season, so the population consisted of distinct age cohorts. These patterns may relate to a highly seasonal food supply.

Kiore elsewhere in New Zealand show seasonal breeding, but the length of breeding, sexual maturation, and litter size vary. Other studies of kiore in the Pacific show less marked seasonal fluctuations, longer breeding seasons, and smaller litters. We propose a model to explain the variation in rodent demography in New Zealand. The model is based on the seasonal availability of food, along with the modifying influences of predation and dispersal.     

Fatty acid composition of the depot fats of the Polynesian rat,Rattus exulans,Tokelau Islands

The fatty acid composition of the stomach contents, adipose tissue, and perinephric fat of Polynesian rats (Rattus exulans Peale), from the Tokelau Is indicated that the dietary fat consisted mainly, if not exclusively, of coconut oil. Lower ratios of lauric : myristic acids were found in the depot fats of the Polynesian rats than in the dietary coconut oil. These results were consistent with chain elongation of lauric to myristic acid after ingestion, as previously reported in rats and other mammals.     

The effect of habitat on the helminth parasites of an island population of the Polynesian rat (Rattus exulans)

Differences in helminth faunal composition, distribution and abundance were studied in three habitats on an island on which the Polynesian rat, Rattus exulans (Peale), is the only rodent present. The effects of season and of host age and sex were also included in the analysis. Habitat had a statistically significant effect on the prevalence and/or abundance of all seven parasites included in this study. Season influenced four species (Brachylaima apoplania, Capillaria sp., Heterakis spumosa and Mastophorus muris) but had little or no detectable effect on the remaining three (Capillaria hepatica, Hymenolepis diminuta and Syphacia muris) . Of the two intrinsic variables, age but not sex was found to have an effect. A comparison of the effects of each variable on parasite prevalence confirmed that habitat was the most important of the four variables. In a prior study on the influence of habitat on host population dynamics on this island, between-habitat differences were shown to include adult longevity, total population density and the seasonal availability and abundance of various food types. These factors, together with physical differences in the microhabitat and the parasite's life cycle, help to provide explanations for the observed results.     

Response of a Tree Weta Population (Hemideina crassidens) After Eradication of the Polynesian Rat from a New Zealand Island

Abstract A population of Hemideina crassidens (the Wellington tree weta) was monitored over a 4‐year period after the eradication of Rattus exulans (the Polynesian rat kiore) and Gallirallus australis australis (the South Island weka) from Nukuwaiata (Chetwode Islands), Pelorus Sound, New Zealand. A novel survey technique (entrance scores) was used in combination with a conventional technique (random searches for active weta) to measure changes in weta population parameters after the removal of predation pressure and to investigate impacts of exotic predators on tree weta. Tree weta density did not increase markedly over the 4‐year period, but the proportion of active adults did increase. Weta were observed to move into larger and more crowded galleries (refuges), to occupy galleries closer to the ground, and to spend less time sitting in gallery entrances. It was concluded that endemic tree weta are well adapted to withstand some introduced vertebrate predators but are able to live a more “relaxed” lifestyle in the absence of this predation. The most significant change detected was in weta age structure, with adults increasing their proportion of the population.     

The breeding biology of the gadfly petrels Pterodroma spp. of the Pitcairn Islands: characteristics, population sizes and controls

This paper reports the breeding biology and nesting seasons of the gadfly petrels which nest on the four islands of the Pitcairn group, Pitcairn, Henderson, Oeno and Ducie. The species currently breeding are Murphy's petrel Pterodroma ultima , Kermadec petrel P. neglecta , Herald petrel P. heraldica and Henderson petrel P. atrata. Of these, Murphy's petrel is the most numerous; an estimated 250000 pairs bred on Ducie, which is probably the major breeding station of the species. Novel basic breeding data for Murphy's petrel are presented. Incubation spells, averaging 19.3 days, are exceptionally long for a petrel. Phoenix petrel P. alba appears to have ceased to breed on the Pitcairn Islands since the 1922 surveys of the Whitney Expedition. Nesting success was low on Henderson Island during the study. For all four breeding species, less than 20% of eggs laid yielded fledglings. Failure occurred at the early chick stage and observations indicated that it was due to predation by Pacific rats Rattus exulans. Although rats are present on Ducie, predation was apparently less severe there. The situation on Oeno may be intermediate. I consider how the populations of Henderson are maintained in the face of this intense predation. The Murphy's petrel population may be sustained by immigration from Ducie while the Herald and Henderson petrel populations could be undergoing a long-term decline on Henderson. It is not clear how the Kermadec petrel population is maintained. The conservation implications of these findings are discussed.     

Coccidioidomycosis of the male reproductive tract

Coccidioides immitis infection of the male reproductive tract is a rare entity that can evade diagnosis and pose a dilemma in management. Initially, patients are often evaluated for malignancy or other infections such as tuberculosis. In the past, surgery was the only management option for C. immitis infection of the male reproductive tract, but azole therapy now provides an adjunct or an alternative. We describe two patients who received azole therapy for C. immitis infection of the male reproductive tract. One received fluconazole for prostatic disease, while one received surgery followed by itraconazole for testicular disease. After 12 months of therapy, both remain asymptomatic and have decreased antibody titers against C. immitis.Disclaimer: The Views expressed herein are those of the authors do not reflect the official policy or position of the Department of the Air Force, Department of the Army, Department of Defence, or the U.S. Government.     

Eradications as reverse invasions: lessons from Pacific rat (Rattus exulans) removals on New Zealand islands

Eradications of kiore or Pacific rats (Rattus exulans) from islands around New Zealand have been followed by responses from resident species of coastal plants, invertebrates, reptiles and seabirds. These responses are compared with an invasion by ship rats (Rattus rattus), which devastated populations of invertebrates, birds and bats. Post-eradication responses only approximate the effects of invasions because recovery is limited to the residual pool of native species. Greater effects of kiore are indicated by adding incompatible species confined to rat-free locations. The extended list includes at least 15 species of invertebrates, two species of frogs, tuatara (Sphenodon punctatus), 11 species of lizards and 9 species of seabirds. The analyses indicate direct and indirect effects of kiore similar to those reported after ship rat invasions. This is despite indications from the literature that kiore are the least damaging of the three commensal rat species.     

Cell-cell interaction underlies formation of fluid in the male reproductive tract of the rat

The epithelia lining the epididymides of many species consists of several cell types. We have provided evidence that the basal cells are essential to the integrated functions of the epithelium. Basal cells, but not principal cells, and other cells in the epididymis express TRPC3 and COX-1. We have isolated basal cells from intact rat epididymis using antibody-coated Dynabeads and subjected them to whole-cell patch-clamp measurement of nonselective cation channel activity, a feature of TRPC3 protein, and Fluo-3 fluorescence measurement of intracellular Ca2+ concentration. The results show that a nonselective cation current blockable by La3+ (0.1 mM), Gd3+ (0.1 mM), or SKF96365 (20 microM) could be activated by lysylbradykinin (200 nM). In cells loaded with Fluo-3, addition of lysylbradykinin (100 nM) caused a sustained increase of intracellular Ca2+. This effect was blocked by Gd3+ (0.1 mM) or SKF96365 (20 microM) and was not observed in Fluo-3-loaded principal cells. Stimulation of basal cell/principal cell cocultures with lysylbradykinin (200 nM) evoked in principal cells a current with CFTR-Cl- channel characteristics. Isolated principal cells in the absence of basal cells did not respond to lysylbradykinin but responded to PGE2 (100 nM) with activation of a CFTR-like current. Basal cells, but not principal cells, released prostaglandin E2 when stimulated with lysylbradykinin (100 nM). The release was blocked by SKF96365 (20 microM) and BAPTA-AM (0.05 or 0.1 mM). Confluent cell monolayers harvested from a mixture of disaggregated principal cells and basal cells responded to lysylbradykinin (100 nM) and PGE2 (500 nM) with an increase in electrogenic anion secretion. The former response was dependent on prostaglandin synthesis as piroxicam blocked the response. However, cell cultures obtained from principal cells alone responded to PGE2 but not to bradykinin. These results support the notion that basal cells regulate principal cells through a Ca2+ and COX signaling pathway.     

New microsatellite markers for the bush rat,Rattus fuscipes greyii: characterization and cross‐species amplification

We describe here 16 new microsatellite markers for the bush rat, Rattus fuscipes greyii, and characterize their cross‐species amplification within the Australian Rattus and at a greater level of divergence in Rattus rattus and Rattus norvegicus. Within R. f. greyii, all of the loci are highly polymorphic, with six to 24 alleles per locus across the species range and expected heterozygosity ranging from 0.48 to 0.90 per locus within a sample of 24 rats from a large population on Kangaroo Island. Cross‐species amplification rates were approximately 87% within the Australian Rattus and approximately 50% within R. rattus and R. norvegicus. These loci are highly polymorphic with a high success rate of cross‐species amplification, making them potentially useful for a wide range of genetic studies.     

Brachylaima apoplania n. sp. (Digenea: Brachylaimidae) from the Polynesian rat, Rattus exulans (Rodentia: Muridae), in New Zealand: origins and zoogeography

Brachylaima apoplania n. sp. is described from the small intestine of the Polynesian rat (Rattus exulans) on Tiritiri Matangi Island, New Zealand. The new species is most similar to Brachylaima ratti Baugh, 1962, from Rattus rattus. The two species differ only in morphometric characters, B. apoplania possessing significantly smaller suckers, pharynx, testes, ovary, and cirrus sac. The close resemblance between B. apoplania and B. ratti, the close relationship between their hosts, and archaeological evidence on the origin and early dispersal of R. exulans are used to hypothesize a common Southeast Asian origin for the 2 Brachylaima species. Brachylaima apoplania is believed to have dispersed subsequently throughout the South Pacific islands, along with its rodent host, in the canoes of the ancestors of the modern Polynesians and Maoris.     

黄毛鼠婚配制度初探:熟悉性对两性间行为的影响

为探究黄毛鼠的婚配制度,通过雌雄黄毛鼠对熟悉和陌生异性鼠的选择实验和遭遇实验,分析了熟悉性对两性间行为的影响.结果发现,选择实验中雌鼠对陌生雄鼠的关注频次比对熟悉雄鼠的更多;遭遇实验中尽管雌鼠探究和自身修饰行为、雄鼠的活动和攻击行为在遭遇熟悉或陌生异性鼠时有差异,但雌雄鼠的友好行为均无显著差异,暗示黄毛鼠是多配制,但需...     

Effects of 1,2-dibromo-3-chloropropane on male reproductive function in the rat

The pesticide 1,2-dibromo-3-chloropropane (DBCP) is a known male reproductive toxin. Previous studies employed production-grade DBCP containing allyl chloride and epichlorohydrin, both capable of producing effects similar to DBCP. The purpose of this study was to determine if purified DBCP caused the same effects as DBCP containing allyl chloride. Rats were injected for 6 mo with varying doses of pure or production-grade DBCP. Very few differences were observed in the parameters measured between pure and production-grade DBCP-treated animals at any one dose level. Treatment with 25 mg/kg DBCP, pure or production grade, reduced body weight as well as the weight of the testes, prostate glands and seminal vesicles, and elevated serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This dose of pure DBCP reduced serum testosterone. Treatment with 5 mg/kg of either grade DBCP caused decreases only in body and testis weights. Animals treated with 1 mg/kg did not show any major differences from controls. These results indicate that DBCP, and probably not a contaminant, is responsible for the effects observed on male reproduction. Furthermore, DBCP appears to affect either androgen action or production since multiple androgenic indices are affected by DBCP administration.     

Effects of alpha-chlorohydrin and gonadectomy on the adenohypophysial cells of male rats and gerbils

The cytological changes occurring in the gonadotropic cells of the anterior lobe of the pituitary in 30 male rats and 30 male gerbils after administration of alpha-chlorohydrin were compared with those occurring following bilateral gonadectomy. A decline in the weights of testes and accessory sex glands and inhibited spermatogenesis were noted in rats and gerbils following alpha-chlorohydrin administration. Alpha-cholorohydrin changed the appearance of the delta-basilphils, cell cytoplasm showed fine granulation and vacuolization, and castration vacuoles appeared in many delta-basiphils of the anteroir lobe of the pituitary. The compound brought about transient changes resembling those of castration in the anterior lobe of the pituitary of male rats and gerbils. In gerbils, there was also a marked decrease in the number of acidophils. The results show that alpha-chlorohydrin exerts its effects on androgen-dependent structures, e.g., seminal vesicles, ventral prostrate, epididymides, and perineal complex.     

新疆褐家鼠种群生命表及其在干旱区的生存能力分析

从2000年至今,曾于野外捕捉的褐家鼠3 837只,其中雌鼠2 685只,雄鼠1 152只,经鉴定划分为幼年组(Ⅰ)、亚成年组(Ⅱ)、成年Ⅰ组(Ⅲ)、成年Ⅱ组Ⅳ、老年组(Ⅴ)等5个年龄组,其年龄结构探讨种群数量动态,结果表明,种群中Ⅱ龄的平均生命期望值最高1.0357,其次为Ⅲ龄0.9488。该种群中1龄个体占优势地位,种群属于增长性种群,种群内禀增长率rm为0.2789/年,年周限增长率λ为1.3217,世代时间T为2.623年,种群经一世代的净增殖率R0为2.0782。