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| 1 | Impact of contraceptive hormones on the reproductive potential of male and female commensal black rats (Rattus rattus)显示文摘The black rat is considered one of the world’s top pests.With increased restrictions on rodenticides,new alternatives to manage rats are urgently needed.Research on the use of contraceptive hormones,levonorgestrel(LE),and quinestrol(QU),have been evaluated against some rodent species,and this research is thefirst study to assess these on black rats.Hormones were incorporated into rodent bait at 10 and 50 ppm concentrations singly and in combination(EP-1).Groups of 10 animals of each sex were fed the baits over 7 days.Lower bait consumption was observed with slight body mass reductions.On dissection,it was observed that the uterus was in a state of edema and male reproductive organs weighed less with reduced sperm counts/motility.The 2 most promising baits,50 ppm QU and EP-1,were used to assess impact on pregnancy and litter size.Pregnancy was reduced from 70%success when both males and females consumed untreated bait,down to 30%when males had consumed contraceptive bait but females had not,and down to 0%when females had consumed contraceptive bait,regardless of whether they had paired with a treated or untreated male.Litter size in the untreated pairs was 8 pups,but only 4 pups in those cases where the male only had consumed the contraceptive.Further studies should investigate how long the effect lasts and its reversibility.Field studies at the population level may also shed light on the practicality of using contraceptive baits for black rats in different habitats. | Mwajabu SELEMANI Rhodes H.MAKUNDI Apia W.MASSAWE Ginethon MHAMPHI Loth S.MULUNGU Steven R.BELMAIN | 2022 | Integrative Zoology2022，17，6： | 0 |
| 2 | Relationship between sampling intensity and precision for estimating damage to maize caused by rodents显示文摘In this study we aimed to determine the relationship between sampling intensity and precision for estimating rodentdamage. We used the systematic row sampling technique to provide data to achieve precision and accuracy inestimations of rodent damage in maize fields at the planting and seedling stages. The actual rodent damage to maizein 15 fields, each 0.5 ha in size, in Morogoro, Tanzania, was established at the seedling stage. These data were usedto simulate the sampling intensities that would provide precision and accuracy. The variations between estimateswere plotted against the sampling intervals. The results of this study show that the relationship between averagestandardized variances and sampling intervals is linear. The heterogeneous distribution of damage in some plotscaused variations in the accuracy of the estimates between plots, but a sampling interval of five rows consistentlyproduced estimates with a variance of less than 10%. We provide a standard curve that will allow a decision to bemade on the sampling intensity as a function of required precision using the systematic row sampling technique inmaize fields. | Loth S.MULUNGU Rhodes H.MAKUNDI Apia W.MASSAWE Herwig LEIRS | 2007 | Integrative Zoology2007，2，3： | 0 |
| 3 | Reproduction and population dynamics of Mastomys natalensis Smith, 1834 in an agricultural landscape in the Western Usambara Mountains, Tanzania显示文摘The multimammate rat,Mastomys natalensis Smith 1834,is a dominant species in agro-ecosystems in Sub-Saharan Africa,but adapts quickly to changes in non-agricultural landscape,particularly woodlands and forests.In this study we report on reproduction and population dynamics of M.natalensis in deforested high elevation localities in the Usambara Mountains,north-east Tanzania.We conducted Capture-Mark-Recapture studies in 2002-2004,and established that reproduction of M.natalensis takes place in the extended wet season between February and June,and the population density peaks in June-August.Reproduction cease in July to January and population density drops from July onwards.Reproduction and population density fluctuations are linked to the duration and amount of rainfall.In years when rainfall was below average and the wet season was short,the population density was significantly lower(below 10 animals/ha and 60 animals/ha in 2003 and 2004 respectively,compared to>100 animals/ha in 2002 when rainfall was above the seasonal average)(Fdf 2,13=9.092,p<0.01 for in between years variations and Fdf_(12,15)=5.389,p<0.01 for effect of cumulative annual rainfall on population density).These densities were much lower than in the lowland savannah habitats in central and southwest Tanzania.A comparison between the farmland/fallow mosaic fields and agro-forestry areas showed higher population densities in the former,which have similarities to the preferred habitats in the lowland savannahs.The increasing abundance of M.natalensis in the Usambara could have some consequences:M.natalensis is major pest and is involved in the plague cycle in the western Usambara Mountains.Mastomys natalensis is also a strong competitor and the impact on endemic rodent species,e.g.Lophuromys flavopunctatus and Praomys delectorum is unknown. | Rhodes H.MAKUNDI Apia W.MASSAWE Loth S.MULUNGU | 2007 | Integrative Zoology2007，2，4： | 0 |
| 4 | Soil type limits population abundance of rodents in crop fields:case study of the multimammate rat Mastomys natalensis Smith,1834 in Tanzania显示文摘Studies of populations of the multimammate rat Mastomys natalensis in Morogoro, Tanzania, show that soil textureappears to influence the population abundance and distribution of these rats in agricultural fields. The lowest rodentpopulation abundance was found on sandy clay soils (F(2, 5) = 8.42;P = 0.025). The population abundances of M.natalensis on sandy clay loam and sandy loam soils did not differ significantly (P ≤ 0.05), possibly because thesesoils have a very similar texture. The results of this study suggest that M. natalensis prefers loam-textured soilswith a high percentage of sand, which are probably better than clay soils for burrowing and nesting, particularly inthe rainy season. The lower preference for clay soils is probably related to the poor aeration in these soils and thewaterlogging that occurs during the wet season. | Apia W.MASSAWE Winnie RWAMUGIRA Herwig LEIRS Rhodes H.MAKUNDI Loth MULUNGU V.NGOWO Robert MACHANG’U | 2008 | Integrative Zoology2008，3，1： | 0 |
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