Volume 72, Issue 3 - Special Issue: 10th International African Small Mammals Symposium (ASMS)

Males and females use different mating strategies and seldom have these strategies been studied on the field for cryptic rodent species. We studied the breeding strategies of both males and females of the sub-Sahara African rodent pest species, Mastomys natalensis , in the field using capture removal and capture-mark-recapture techniques combined with microsatellite analyses. In total, 36 litters (359 young) and 94 candidate fathers were genotyped. Multiple paternity (more than one male per litter) occurs frequently in all sampled grids (>47% of all litters). Paternity assignment success rates are relatively high (mean 69%). Males are polygynous, but this is less frequent than female polyandry. Large differences in male reproductive success exist with a large part of the male population without offspring in our sample. Larger males father significantly more offspring. Spatial analyses do not show a strict spatial organisation. Our data suggest male M. natalensis roam around to mate with as many females as possible, while females also mate with several males to produce litters fathered by several males. This species could be an interesting candidate for testing virally vectored immunocontraception as a pest management technique due to the promiscuous mating and high frequency of sexual contacts.

Multiple captures (i.e., the simultaneous capture of two or more individuals in the same trap) in rodent populations provide useful information on their social structure. Adding genetic analyses to these data enables to describe social links between individuals at a finer level. Here, we analyze the distribution and composition of multiple captures obtained during a 3-year study of a population of the murid rodent Mastomys huberti in Mali. In total, 133 multiple captures were recorded, representing more than 17% of the total number of individual capture events. Seasonal variations in the incidence of multiple captures were observed, and the young (classified as juveniles or subadults) were involved in multiple captures more often than expected. Juveniles (<21 g) were captured together more often than expected, suggesting that they usually forage in groups. This trend was also observed in subadults (<31 g), accompanied by a clear deficit of captures involving one subadult and one adult of the same sex, especially in males. This pattern could illustrate a phase when negative intraspecific interactions occur, possibly linked to dispersal of subadult males. Genotypic characterization of a significant fraction of the population using 11 microsatellite loci enabled to show that individuals caught together were significantly more closely related than those involved in single captures, even when close from each other. A seasonal trend of relatedness of these co-captured animals was also confirmed.

We studied the feeding habits of Mastomys natalensis by analysing a total of 2934 stomachs from individuals snap trapped from maize fields and the surrounding fallow land of central and southwestern Tanzania between February 2001 and October 2002. Mastomys natalensis had a wide range of food items in their diet; however, there was a clear seasonal effect on the consumption of the different food categories. They fed more on seeds, arthropods and grasses during the wet season and on the other plant materials during the dry season. Maize seed was the most preferred diet category, when available. The shifts towards greater consumption of maize, when available, coupled by the high densities attained by this species render it the greatest potential rodent pest in the study areas.

A total of 750 rodents and shrews were trapped in several sites on Mount (Mt.) Kilimanjaro and in two lowland sites between October 2002 and August 2003. Species diversity variations with altitude and their distribution were established. Diversity of species varied with vegetation type, being highest in the forest and lowest in the lowland areas. The distribution patterns and species diversity of the rodents and shrews were also influenced by habitat complexity and heterogeneity. Species richness was higher in the forest compared to the other areas. The study generally shows that the Mt. Kilimanjaro has high rodent and shrew species diversity and richness.

This study quantifies habitat-specific small mammal patterns in the Caledon Nature Reserve, Free State province, South Africa. Small mammal community variables were correlated with an Ecological Index, the current method used to interpret habitat integrity in Free State nature reserves. It also reports on the seasonal abundance, species richness and diversity of small mammals present in specific habitats and addresses the most successful methods to sample these taxa, such as the duration of trapping to ensure unbiased sampling, and in which season should effort be concentrated to obtain optimal results. Our results support expectations that small mammal species richness increase with Ecological Index value, the number of specialist species in Free State grasslands increases with succession up to the climax phase, and that Mastomys coucha dominance acts as an indicator of habitat disturbance. It also supports previous studies that have shown a minimum trapping period of 3 days and nights, and best trap success and species richness at the end of autumn–early winter.

We conducted a survey on rodent crop damage among farmers in the hinterland of Kisangani (Democratic Republic of Congo). We studied the amount of crop damage, the rodent groups causing crop damage, the growth stages affected and the control techniques used. We conducted this survey in three municipalities using a standard questionnaire form translated into local languages, between November 2005 and June 2006 and during July 2007. We used the Quotas method and interviewed 70 households per municipality. Farmers indicated rodent groups implicated in crop damage on color photographs. Two types of survey techniques were used: individual and focus-group surveys. The sugar cane rat, Thryonomys sp. and Lemniscomys striatus caused most damage to crops, but inside granaries, Rattus rattus was the primary pest species eating stored food supplies and causing damage to stored goods. Cassava and maize were the most cultivated crops, followed by rice. Maize and rice are the most vulnerable during the heading stage. The most usable part of cassava (tubers) was attacked less often. Farmers mostly applied traditional trapping techniques, using local snap traps to decrease rodent abundance and sometimes used a labor-intensive trap-barrier system to trap Thryonomys . Inside buildings (granaries), farmers used chemical control methods.

The conservation of biodiversity and sustainable management strategies must be based on an understanding of the structural and functional ecological traits of utilized species. Such basic data are still lacking for even the most endangered species in Africa. In this study, we combined ecological methods with ethnographic approaches to investigate the ecology and ethnozoology of three-cusped pangolin (Manis tricuspis ) in the context of the Lama forest reserve (6°55.8′–58.8′ N and 2°4.2′–10.8′ E) in Benin. We interviewed 79 people from various socio-professional groups to assess how important is three-cusped pangolin to indigenous people. We surveyed 15 strip transects (3 km×1 km) within 12 sites to seek for indices of pangolin presence and record-associated vegetation data in six plots of 900 m 2 (30 m×30 m). In total, 38 pangolins were observed in the forest. The density was 0.84 pangolins/km 2 during the dry season and the number of observations did not differ significantly between plantations and natural forest. The age ratio of juvenile/adult was 1:1. The preferred habitat was colonized by termite mounds in 62% of the sites. Pangolins were mostly found in holes of Dialium guineense and Ceiba pentandra in the closed natural forests. The distribution of pangolins in the Lama forest reserve suggests that the species is more sensitive to forest age than to its composition. Three-cusped pangolin plays an important role as food, medicine, mythic and source of income for local communities around the Lama forest reserve. We also recommend future research guidelines important for the conservation of Manis tricuspis in Benin.

We investigated the efficiency of four trap types (pitfall, Sherman LFA, Victor snap and Museum Special snap traps) to capture shrews. This experiment was conducted in five inter-riverine forest blocks in the region of Kisangani. The total trapping effort was 6,300, 9,240, 5,280 and 5,460 trap-nights for the pitfall, Sherman, Victor and Museum Special traps, respectively. In total, we captured 366 shrews. The use of pitfall traps yielded the highest trapping success (4.1) with at least 18 shrew species identified. Trapping success and the number of species collected was lower for the Sherman (0.6, at least 11 species), Victor (0.6, at least 8 species) and Museum Special (0.5, at least 6 species) traps. Although Crocidura olivieri and C. denti were caught using all four trap types, captures with different trap types did not produce a sample with the same taxonomic composition. In agreement with previous studies, our results indicate that pitfall traps are the most efficient for capturing shrews: not only do they have a higher efficiency (yield), but the taxonomic diversity of shrews is also higher when pitfall traps are used.

Research on the biodiversity of shrews was conducted in eight forest blocks at eight sampling localities: Djabir, Maiko, Masako, Yoko, Yelenge, Baliko, Bomane-1 and Bomane-2. We used pitfall traps combined with Sherman LFA traps placed on transects. We collected 724 shrews from primary forests, secondary forests, old fallow lands and old palm plantation for a total of 18,900 trap-nights. Shrews collected represent 5 genera and at least 19 species: Scutisorex (1 species), Crocidura (12 species), Paracrocidura (2 species), Sylvisorex (3 species) and Suncus (1 species). Sylvisorex nov. sp. is currently being described as a new species for the Kisangani region. Primary forests (16 species), secondary forests (17 species) and old fallow lands (16 species) are the habitats with higher species diversity. In an old palm plantation, only five species have been collected. Crocidura olivieri was caught in all types of prospected habitats. C. cf muricauda was only caught in old palm plantation and C. grassei only in old fallow land. Sylvisorex johnstoni was caught mainly in primary forest. Species composition is different for the different forest blocks studied, possibly indicating some influence of the larger rivers separating our sampling localities as natural barriers.

Praomys (four species), Lophuromys (four) and Deomys (one) are among the most common Muridae in the Kisangani region. To establish whether or not rivers constitute dispersal barriers for these rodents, we investigated the presence of these genera and their species in eight localities that are either separated by the Congo River or its tributaries. A total of 42,466 trapping nights resulted in the collection of 1185 Praomys , 233 Lophuromys and 209 Deomys ferrugineus . We observed that in almost all cases the studied species appear to have restricted distribution ranges, and that it is likely that the importance of the rivers as a barrier differs for the studied species. For example, P. misonnei was only collected from the right bank of the Congo, while P. lukolelae appears to be restricted to the left bank. In contrast, Praomys identified as P. mutoni or as members of the P. jacksoni species complex are collected on both sides of the Congo River. In contrast, all Lophuromys species were collected in a limited number of sampling sites only. L. dudui and L. luteogaster were only collected along the right bank of the Congo River, and the latter species appears to be restricted to the right bank of the Lindi River. L. huttereri and L. rita are only detected on the left bank of the Congo River. However, additional sampling is required to confirm that D. ferrugineus and L. luteogaster (so far both species have only been recorded on the right bank) do not occur in Bomane on the right bank of the Aruwimi (Ituri) River. In agreement with earlier findings for larger mammals, and pending additional taxonomical work on the P. jacksoni species complex, our findings confirm that the Congo River constitutes a barrier that limits the dispersal of all studied murids, except P. mutoni .

This study was carried out to identify distinguishing morphometric characters between taxa from the genus Cricetomys in the rainforest. Specimens were captured from localities in the rainforest zone of South Western Nigeria, and 22 classic morphometric distances were taken on the skulls. Statistical analysis of morphometric data was carried out using principal component analysis and canonical variate analysis. In the principal component analysis, zygomatic width, rostrum depth, mandible length, incisive foramen length, and interorbital width represent the heaviest loading characters involved in separating male specimens of C. emini from C. gambianus . Among males, morphometric separation of these two species of Cricetomys was found to concur with pelage characterizations. Female specimens of C. emini and C. gambianus , however, could not be distinctly separated morphometrically, but nasal length, upper diastema length, rostrum depth, mandible length, mandible depth, zygomatic width, and parietal width are among the heaviest loadings involved in their partial separation. Moreover, morphometric data and pelage patterns do not produce identical characterizations of female specimens. Findings from this study reinforce the view that pelage characterizations are not entirely reliable in distinguishing taxa within Cricetomys . The morphometric characters identified in this study will contribute to more a reliable identification of giant pouched rat species within forests of Africa.

Recent investigations in Guinea and Ivory Coast showed that Mus ( Nannomys ) are hosts of new arenaviruses. However, the taxonomy and biogeography of the western pygmy mice are poorly known, as this genus contains many cryptic species. To improve our taxonomic knowledge on this subgenus and its distribution range in West Africa, we performed a molecular, cytogenetical and morphological study of all Mus ( Nannomys ) species in this part of Africa. This approach allowed us to detect five species in Guinea ( Mus mattheyi , M. minutoides , M. setulosus , M. baoulei , M. musculoides ) and four ( M. minutoides , M. setulosus , M. baoulei , M. musculoides ) in Ivory Coast. Our molecular results confirm the validity of M. baoulei and the extended distribution range of M. mattheyi . We also observed a high degree of genetic differentiation between and within these species, especially within the M. setulosus clade which may be a species complex. The canonical analyses on the craniometrical and external morphological features of the sequenced specimens are insufficient to perfectly separate the studied species. Nevertheless, our results confirm that M. setulosus and M. baoulei are the largest Mus species that occur in Guinea and Ivory Coast. M. baoulei can be distinguished by its short tail and M. setulosus by an enlarged and bilobated lower molar (M3). Among the smaller species, M. musculoides is difficult to identify using morphological data alone, but differences in tail length proportions, size of tympanic bullae, the length and shape of the upper dental row allow identification of this species with some confidence. Our results allow us to provide some conclusions about the distribution ranges of the studied Mus ( Nannomys) spp. in both countries and to discuss their presence in relation to vegetation, habitat and human settlements.

This study investigated mammalian involvement in an outbreak of bubonic plague in Mbulu District, northern Tanzania, in March 2007. Plague is a rodent-borne zoonotic disease that spreads to humans through fleas infected with Yersinia pestis . Live trapping of rodents and shrews was conducted in fallow and crop fields, peri-domestic areas, houses and the neighboring forest reserve. Serum was separated from blood of captured animals. A rapid diagnostic test (RDT) was used for diagnosis of plague infection. An ELISA technique was used to detect antibodies against Yersinia pestis fraction 1 antigen. Wild and commensal rodents tested positive by RDT, indicating current infection in clinically healthy animals. The ELISA showed that wild rodents ( Lophuromys flavopunctatus , Praomys delectorum , Graphiurus murinus , Lemniscomys striatus ) and commensal rats ( Rattus rattus , Mastomys natalensis , Mus minutoides ) were Y. pestis -positive. Two potential vectors, Xenopsylla brasiliensis and Dinopsyllus lypusus , were found on wild and commensal rodents with a flea index of 1.8. We conclude that diverse potential mammalian reservoirs and efficient vectors of Y. pestis are present in abundance in Dongobesh and could lead to persistence and future plague outbreaks.