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We examine possible ways of functional adjustment of morphologically similar alimentary tracts in rodents with different dietary specializations. We study the structure of stomach and gut epithelial surface as well as the features of its colonization with microorganisms in five gerbil species:Psammomys obesus, Meriones crassus, Gerbillus henleyi, G. andersoni, andG. dasyurus. Data on the morphological diversity of mucosa-associated microbiota have been obtained and confirmed by the results of previous microbiology studies. Species differences in chymus acidity associated with dietary specialization have been determined. Variations in the activity of the endoglucanase microbial enzyme, which is crucial for rodents fed on cellulose-containing food, have also been detected. The importance of microbiota for functional adaptations to various food types in rodents with morphologically similar digestive tracts has been evaluated.

The strong dependency of some vectors on their host as a source of habitat can be viewed as a weak link in pathogen’s transmission cycles using the vertebrate host as a ‘Trojan horse’ to deliver insecticides directly to the vector-host point of contact (hereafter ‘systemic control’). This could, simultaneously, affect the survival of blood-feeding females and coprophagic larvae. Sand-flies, vectors of leishmaniasis worldwide, are often dependent on their bloodmeal host as a source of habitat and may therefore be good candidates for systemic control. In the present study, we field-tested this methodology by baiting Meriones crassus (Sundevall, 1842) (Rodentia:Muridea) with Fipronil-treated food pellets and evaluated its effect on reducing sand-fly emergence rate, in general, and of that of blood-fed females, in particular. We demonstrated 86% reduction in the abundance of female sand-flies that exit burrows of Fipronil-treated jirds, whereas male abundance was unaffected. Furthermore, whereas in control burrows 20% of the females were blood-fed, in treatment burrows no blood-fed females were detected. Sand-fly abundance outside the burrows was not affected by burrow treatment. This highlights the focal specificity of this method: affecting female sand-flies that feed on the reservoir host. This should result in the reduction of the pathogen transmission rate in the vicinity of the treated area by reducing the prevalence of leishmania-infected sand-fly females. These results hold promise for the potential of the systemic control approach in this system. Our next-step goal is to test this methodology at a large-scale cutaneous leishmaniasis control program.

espanolLos roedores de la subfamilia Gerbillinae Gray, 1825, representan un importante componente de la fauna de pequeno tamano de regiones aridas y deserticas de Africa y Asia. El jerbo de Sundevall Meriones crassus es una de las especies deserticas mas extendidas de esta subfamilia y esta distribuido desde Marruecos hasta Pakistan. En este estudio secuenciamos el gen citocromo b del ADN mitocondrial de dos especimenes capturados en Marruecos, lo que constituye la primera identificacion genetica de esta especie en el continente africano. La identificacion molecular se complemento y confirmo con evidencia morfologica. Ademas, propusimos la hipotesis de una extension de su distribucion geografica 250 km hacia el norte en Marruecos, quiza indicativa de la creciente desertificacion que afecta al norte de Africa. La confirmacion de dicha hipotesis requerira pruebas adicionales. catalaEls rosegadors de la subfamilia Gerbillinae Gray, 1825, representen un component important de la fauna de mida petita de regions arides i desertiques d’Africa i Asia. El jerbu de Sundevall Meriones crassus es una de les especies desertiques mes esteses d’aquesta subfamilia i esta distribuit des del Marroc fins al Pakistan. En aquest estudi sequenciem el gen citocrom b de l’ADN mitocondrial de dos especimens capturats al Marroc, la qual cosa constitueix la primera identificacio genetica d’aquesta especie al continent africa. La identificacio molecular es va complementar i confirmar amb evidencia morfologica. A mes a mes, vam proposar la hipotesi d’una extensio de la seva distribucio geografica 250 km cap al nord al Marroc, potser indicativa de la creixent desertitzacio que afecta el nord d’Africa. La confirmacio d’aquesta hipotesi requerira proves addicionals. EnglishRodents from the subfamily Gerbillinae Gray, 1825, are an important component of small fauna in arid and desertic regions in Africa and Asia. Among this group of rodents, Sundevall’s jird, Meriones crassus, is one of the most widespread desert species, found in countries ranging from Morocco to Pakistan. In this study, we sequenced the cytochrome b gene of the mitochondrial DNA in two specimens captured in Morocco, constituting the first genetic identification for this species in the African continent. Molecular identification was complemented and supported with morphological evidence. Additionally, we propose the hypothesis of a northward extension of 250 km of the geographic distribution of Sundevall’s jird in Morocco, perhaps indicating the increasing desertification affecting North Africa. Further evidence will be required to test the latter hypothesis.

Leishmania major (Yakimoff & Schokhor, 1914), an important causative agent of Old World Cutaneous Leishmaniasis (CL), is transmitted by sand flies among a limited number of gerbilline reservoir-species. We can take advantage of this strong dependency to break the pathogen transmission cycle by using systemic insecticides that render the host toxic to the blood-feeding vector. We evaluated the potential of this approach with two novel reservoir species, incriminated for CL expansion in several sites in the Middle East. Specifically, we evaluated: 1) the residuality of the systemic insecticide fipronil in Meriones tristrami (Thomas, 1892) fed on fipronil-treated baits and 2) the treatments’ adulticide effect on sand flies that blood fed on treated and untreated M. tristrami and M. crassus (Sundevall, 1842). We fed M. tristrami with food pellets containing 0.1 g/kg fipronil and used gas chromatograph–mass spectrometery analysis and bioassays to examine its residual toxicity to blood-feeding female sand flies. In M. tristrami, fipronil was rapidly metabolized to fipronil sulfone, found in the blood, urine, and feces for ≥31 d after fipronil admission. The survival of sand flies that blood fed on fipronil-treated M. tristrami and M. crassus was significantly reduced for at least 15 and 9 d respectively, after fipronil admission. These results hold promise for the potential contribution of systemic control approaches to CL integrated management strategies against novel CL (due to L. major) outbreaks in Israel and elsewhere.

Deserts rodents coexistence has been mainly attributed to resource partitioning at different scales, from macro to microhabitat. We explore the structure of a rodent community in a North African desert under the hypothesis of resource partition. We present the first data of habitat selection by several Gerbilline rodent species in North Africa (Tunisia). Animals were trapped during one season in four locations of the Tunisian desert (Bou-Hedma National Park). Macrohabitat selection was assessed by RDA and variance partitioning. The effect of macrohabitat variables on species richness was assessed by Poisson GLZ and multimodel averaging. Microhabitat selection was evaluated by GLMM and multimodel averaging. Our results support the configuration of two desert rodents assemblages in this region: one characterized by species requiring disaggregated soil, probably for burrowing necessities (Gerbillus tarabuli, Meriones crassus, Gerbillus campestris); and the other one characterized by species maximizing shrub cover, presumably related to food availability and predation risk (Meriones shawii and Gerbillus amoenus). Gerbillus gerbillus seems to have a specially distinctive microhabitat selection pattern. Our results at the microhabitat scale highlight the role that floristic composition can play to segregate between rodent species.

Background: Rodents are one of the most important hosts for some zoonotic diseases and also act as a reservoir of some ectoparasites and endoparasites. They cause damage to the farms and inflict public health. The aim of this study was to investigate the faunal composition of rodent in North Khorasan Province, Northeast of Iran.Methods: The sampling was carried out between 2011 to 2013. The specimens were collected using different methods including rodent death and live traps, digging of their burrow, and hand net from 75 different sample sites.Results: The total number of 396 specimens belonging to 22 species and six families were identified. The results illustrated the high numbers and densities of Meriones persicus (17.68%), Meriones libycus (15.15%), Nesokia indica (7.32%) and Rhombomys opimus (6.82%), as the most important reservoirs for different zoonotic diseases. Moreover, significant number of other rodent species including Mus musculus (15.66%), Apodemus witherbyi (13.89%), A. hyrcanicus (0.25%), Rattus norvegicus (1.01%), Meriones crassus (0.25%), Gerbillus nanus (0.51%), Microtus paradoxus (2.27%), M. transcaspicus (0.76%), Ellobius fuscocapillus (0.25%), Cricetulus migratorius (4.29%), Calomyscus elburzensis (4.29%), C. mystax (1.26%), Spermophilus fulvus (0.25%), Dryomys nitedula (3.54%), Allactaga elater (3.54%), Jaculus blanfordi (0.25%), Meriones zarudnyi (0.25%), M. meridianus (0.51%), and Hystrix indica as hosts for parasites and zoonotic diseases were identified.Conclusion: The high biodiversity including at least 22 species and six families of rodents were found in North Khorasan Province, some of them were medically important species.

Commensal rodents as well as wild ones may present a potential risk to public health. They are reservoirs or vectors of many pathogens. This review provides an update on their epidemiological role in the spread of leishmaniasis in Morocco. In Morocco, the order Rodentia is represented by 7 families and 32 species of which Rattus norvegicus, Psammomys obesus, Mastomys erythrolecus, Meriones shawi, Meriones crassus and Meriones libycus are considered reservoirs of leishmaniasis in Asia, Midle East and Africa. With the aim to define the extent of zoonotic leishmaniasis risk in Morocco, we represent and discuss the geographical distribution of these potential reservoirs in relation to that of Phlebotomus papatasi, proven vector of cutaneous leishmaniasis by Leishmania major in Morocco.

Meriones (Pallasiomys) crassus Sundevall, 1842 Common name: Sundevall's jird, Sand jird, Silk jird, Gentle jird. Diagnosis: Large jird with soft, dense fur. Fur color pale sandy dorsally, underside pure white, line of demarcation not very distinct. Ears small and not pigmented, claws white or pale (Figure 53). Hind feet covered with white hair. Tail terminates with a black brush (not as well developed as in M. libycus). Tail length is about equal to head body length. Skull robust, with extremely large bullae that extend quite beyond the supraoccipital. Braincase broad. The suprameatal triangle of bullae large and widely open at its posterior end. Upper incisors with anterior median groove (Figure 54). Localities: Previous records. Suwira (Allen, 1915); Al Jafr, Azraq (Atallah, 1978); S Wādī ���Araba (Qumsiyeh et al., 1986); ���Aqaba, Azraq, Ghazaleh, Al Qaţrānah (Amr & Disi, 1988); Wādī Khuneizīra (Harrison & Bates, 1991); Wādī Al Hashad (Al-Melhim et al., 1997); S Azraq (Amr et al., 1997); Wādī Ramm (Benda & S��dlov�� (1999); Faydat ad Dahik (Rifai etal., 2000); Al Hazīm, Buqay���awiyah, Faydat ad Dahik, Al Qaţţāfī, Ash Shawmarī Wildlife Reserve, Wādī Al Hashad, Wādī Salma, (Abu Baker & Amr, 2003b); Al Mudawwarah (Abu Baker & Amr, 2004); Ash Shawmarī Wildlife Reserve (Abu Baker et al., 2005). Materials from owl pellets. Qaşr Al Kharanah (Obuch per. com.), Qaşr al ���allābāt (Obuch per. com.), Ash Shawmarī Wildlife Reserve (Obuch per. com.). New records. Qaşr ���Amra (Figure 55). Habitat: This is one of the most common jirds inhabiting the dry and arid habitats of Jordan. It prefers sand areas and hammada (Atallah, 1978). According to Atallah (1977), Sundevall's jird does not form colonies. Abu Dieyeh (1988) described the burrow system of the Sundevall's jird in Wādī ���Araba. The burrow has elaborate tunnels that may reach several meters with several food and nesting chambers. Biology: It feeds on a variety of food items including desert plants, animal dung and insects (Qumsiyeh, 1996). This is a nocturnal species, but may also forage during the day. It was observed near camel feeding areas, and comes during daytime to feed on barely and other vegetable matters. Breeding occurs during the cooler months, but may breed all year round, producing up to three litters a year. Litter size is around 3 to 7 young. The burrow system is simple with a single entrance and one food chamber. Litter size varies between 2 and 7 (Yiğit et al., 1996). Remarks: This is widespread species with different subspecies along its distribution range. The karyotype for specimens collected from Jordan yeiled 2n=60 and FN=70 (Qumsiyeh et al., 1986)., Published as part of Amr, Zuhair S., Abu, Mohammad A., Qumsiyeh, Mazin & Eid, Ehab, 2018, Systematics, distribution and ecological analysis of rodents in Jordan, pp. 1-94 in Zootaxa 4397 (1) on pages 48-49, DOI: 10.11646/zootaxa.4397.1.1, http://zenodo.org/record/1202783, {"references":["Allen, G. M. (1915) Mammals obtained by the Phillips Palestine Expedition. Bulletin of the Museum of Comparative Zoolology of Harvard University, 59 (1), 3 - 14.","Amr, Z. S. & Disi, A. M. (1988) Jordanian Mammals Acquired by the Jordan University Natural History Museum. Publication of the University of Jordan, Amman, 32 pp.","Abu Baker, M. & Amr, Z. (2003 b) Rodent diversity in the Northeastern Desert of Jordan, with special reference on the ecology of Gerbillus cheesmani. (Mammalia: Rodentia). Casopis Narodniho Muzea, Rada prirodovedna, 172 (1 - 4), 141 - 152.","Abu Baker, M., Qarqaz, M. & Amr, Z. (2005) Small mammal remains recovered from pellets of the Barn Owl (Tyto alba) at Shawmari Wildlife Reserve, eastern Jordan. Casopis Narodniho Muzea, Rada prirodovedna, 174 (1 - 4), 12 7 - 129.","Abu Dieyeh, M. H. (1988) The Ecology of some rodents in Wadi Araba with special reference to Acomys cahirinus. M. S. thesis. Jordan University. Amman, 216 pp."]}

Distributional and ecological data were given to all rodents of Jordan. The rodent fauna of Jordan consists of 28 species with 20 genera in eight families (Cricetidae, Dipodidae, Gliridae, Hystricidae, Muridae, Myocastoridae, Sciuridae,and Spalacidae), including four introduced species.Keys for families and species were provided, along with diagnosis for each species and cranial illustrations for most species. Habitat preference and zoogeographic affinities of rodents in Jordan wereanalyzed, as well as their status and conservation.Threat categories and causes of threats on the rodents of Jordan were also analyzed. The distribution of rodents in Jordan represents a reflection of their global distribution ranges and habitat preferences. Species associated with the temperate forest of northern Jordan includes Sciurus anomalus and two wood mice, Apodemus mystacinus and A. flavicollis, while non-forested areas are represented by Nannospalax ehrenbergi and Microtus guentheri. Strict sand dwellers include Gerbillus cheesmani and G. gerbillus. Petrophiles associated with sandstone or black lava deserts are exemplified by Acomys russatus, A. r. lewsi, H. indica and S. calurus. Others including: Jaculus jaculus, G. nanus, G. henleyi, Meriones crassus, and M. libycus are all desert-adapted species with wider ranges of distribution where scarce vegetation, wadibeds, and marabs with clay, loess, or gravel surfaces provide foraging grounds and shelter. A single species, Gerbillus dasyurus, exhibits a wide range of distribution over diverse habitat types. The rodent fauna of Jordan consists of assemblages of different zoogeographical affinities. Nine, three, and seven were restricted or had most of its range within the Mediterranean, Irano-Turanian, and Saharo Arabian, respectively. Sciurus anomalus, Apodemus sp., Nannospalax ehrenbergi, and Microtus guentheri reached their most southern range of distribution in the Mediterranean regions of Jordan. The distribution of Gerbillus cheesmani extends from Asian deserts in India westwards into the Arabian Peninsula crossing Jordan as its most western range of distribution. Typical rodents of Saharo-Arabian affinities are represented by desert jerboas, gerbils, and jirds. North African species such as G. andersoni, G. gerbillus reached their most eastern distribution in southern Jordan. Both G. henleyi and G. nanus are widely-distributed species across North Africa reaching as far as India to the east, representing most northern outpost for these two species. Sekeetamys calurus is a nearly endemic to the Eastern Mediterranean region within southern Jordan and Sinai. Relicts are represented by Eliomys melanurus and Acomys russatus lewisi. Several threats affecting the rodent biodiversity in Jordan were identified including habitat loss and degradation, human disturbance and related activity, legislative and public awareness. The global conservation status of the rodents of Jordan according to the IUCN Red List include 22 species as least concern, one as near threatened (Allactaga euphratica), and one as data deficient (Nannospalax ehrenbergi). According to the regional assessment, one species is critically endangered, three species are considered endangered, one vulnerable.

138. Sundevall’s Jird Meriones crassus French: Mérione de Sundevall / German: Sundevall-Rennratte / Spanish: Gerbillo de Sundevall Other common names: Gentle Jird, Jerusalem Jird, Silky Jird Taxonomy. Meriones crassus Sundevall, 1842, Fount of Moses (Ain Moses), Sinai, Egypt. Meriones crassus 1s distinguished by mor- phological features and chromosomal data. It has been revised by many authors, generally at regional scale. J. Darvish in 201 1 revised morphology of nearly all species of Meriones and provided a tree where M. crassus is close to M. menridianus and M. unguiculatus. M. Ito and colleagues in 2010 found M. crassus close to M. rex in a clade with M. libycus. Monotypic. Distribution. N Africa (from Morocco and Mauritania E to Egypt and NE Sudan), Middle East, S Turkmenistan, W & S Afghanistan, and W Pakistan. Descriptive notes. Head—body 100-153 mm, tail 98-158 mm, ear 14-22 mm, hindfoot 30-38 mm; weight 55-158 g. Tail of Sundevall’s Jird is long (100% of head-body length), and terminal tuft is grayish to chestnut (with strong variation) and less developed than that of Libyan Jird (M. libycus); dorsal proximal part oftail is off-white, with dark brown tuft at end. According to Darvish in 2009, tail length increases from western Iranian Plateau toward Iraq and North Africa. Soles of hindfeet are partly hairy; heel is hairless, with fine line of demarcation. Claws are ivory-white. Dorsum is gray and underbelly white. Skull is less robust than that of Libyan Jird, but is characterized by voluminous tympanic bullae extending posteriorly to paroccipital processes. Females bear four pairs of mammae. Chromosomal complement has 2n = 60, FN = 72. Habitat. Sundevall’s Jird is typically a Saharan species in North Africa, but can be found also in steppic semi-dry environments. It seems to prefer sandy soils, but may occur also in rocky areas in “wadis” (ephemeral riverbeds) and “hamadas” (barren, hard, rocky plateaus). It can wander far from vegetation. In North Africa it was reported also as feeding on succulent stems, fruits and insects. Food and Feeding. In Arabia, Sundevall’s Jirds eat acacias (Acacia, Fabaceae) or colocynths (Citrullus, Cucurbitaceae) as well as Medicago (Fabaceae) seeds, and at certain times also some Schistocerca locusts. In Iran, they feed on seeds of Peganum harmala (Nitrariaceae). In Egypt, remnants of Cassia acutifolia (Fabaceae) were found in the burrows and Sundevall’s Jirds have been observed feeding on seeds of Colocynthis vulgaris (Cucurbitaceae), Anabasis articulata (Amaranthaceae), and Zilla (Brassicaceae). In Israel they preferred saltbush (Atriplex halimus, Amaranthaceae) and Moricandia nitens (Brassicaceae) plants. Their metabolism allows these jirds to concentrate and recycle water, and they can withstand strong dehydration. Breeding. Gestation takes 21-31 days, and pregnant females have 3-7 embryos. Spring and early summer correspond to birth peak. Young are naked and blind until two weeks of life, and are weaned after one month. Sexual maturity is reached at around two months. Activity patterns. Nocturnal, and terrestrial, digging burrows. Sundevall’s Jirds are known to be nomadic, and will move to another site when resources are finished or too poor. They emerge from burrows about one hour after dusk. Burrow architecture is variable in complexity, and abandoned burrows are sometimes “recycled.” Some may have 18 entrances,extend up to 12 m in length, and be very deep (1-2 m); mean depth beneath surface in Morocco is 0-37 m. Many galleries are “culs de sac” and end below surface. Nest chamber is lined with dry shredded vegetation. Movements, Home range and Social organization. Sundevall’s Jird is not colonial but can be gregarious or solitary. Communication is via podophony (foot-tapping), and the animals can respond to high-intensity ultrasonic sounds. They can forage over long distances (up to 10 km reported). They store food in special chambers in their burrows. Status and Conservation. Classified as Least Concern on The IUCN Red List. No major threats are known for Sundevall’s Jird. It may be found close to agricultural regions in south Tunisia. It can be common in some environments, and densities of 0-1-11 ind/ ha have been reported. Bibliography. Amr (2000), Aulagnier et al. (2009), Darvish (2009, 2011), Granjon & Duplantier (2009), Happold (2013a), Ito et al. (2010), Kam et al. (1997), Koffler (1972), Kowalski & Rzebik-Kowalska (1991), Krasnov et al. (1996), Krystufek & Vohralik (2009), Petter (1961c), Qumsiyeh (1996), Ranck (1968), Shenbrot et al. (2002)., Published as part of Don E. Wilson, Russell A. Mittermeier & Thomas E. Lacher, Jr, 2017, Muridae, pp. 536-884 in Handbook of the Mammals of the World – Volume 7 Rodents II, Barcelona :Lynx Edicions on page 643, DOI: 10.5281/zenodo.6887260

Cutaneous leishmaniasis (CL) is a neglected clinical form of public health importance that is quite prevalent in the northern and eastern parts of Egypt. A comprehensive study over seven years (January 2005-December 2011) was conducted to track CL transmission with respect to both sandfly vectors and animal reservoirs. The study identified six sandfly species collected from different districts in North Sinai: Phlebotomus papatasi, Phlebotomus kazeruni, Phlebotomus sergenti, Phlebotomus alexandri, Sergentomyia antennata and Sergentomyia clydei. Leishmania (-)-like flagellates were identified in 15 P. papatasi individuals (0.5% of 3,008 dissected females). Rodent populations were sampled in the same districts where sandflies were collected and eight species were identified: Rattus norvegicus (n = 39), Rattus rattus frugivorous (n = 13), Rattus rattus alexandrinus (n = 4), Gerbillus pyramidum floweri (n = 38), Gerbillus andersoni (n = 28), Mus musculus (n = 5), Meriones sacramenti (n = 22) and Meriones crassus (n = 10). Thirty-two rodents were found to be positive for Leishmania infection (20.12% of 159 examined rodents). Only Leishmania major was isolated and identified in 100% of the parasite samples. The diversity of both the vector and rodent populations was examined using diversity indices and clustering approaches.

SUMMARYWe investigated offspring quality in fleas (Xenopsylla ramesis) feeding on non-reproducing, pregnant or lactating rodents (Meriones crassus) and asked whether (a) quality of flea offspring differs dependent on host reproductive status; (b) fleas trade off offspring quantity for quality; and (c) quality variables are inter-correlated. Emergence success was highest when parents exploited pregnant hosts, while development time was longest when parents exploited lactating hosts. Male offspring from fleas fed on non-reproductive and pregnant hosts were larger than those from lactating hosts whereas female offspring from fleas fed on pregnant hosts were larger than those from both lactating and non-reproductive hosts. Male offspring survived under starvation the longest when their parents exploited lactating hosts and the shortest when their parents exploited pregnant hosts. Female offspring of parents that exploited lactating hosts survived under starvation longer than those that exploited non-reproductive and pregnant hosts. Emergence success and development time decreased as mean number of eggs laid by mothers increased. Fleas that were larger and took longer to develop lived significantly longer under starvation. These results indicate the presence of a trade-off between offspring quantity and quality in fleas exploiting female Sundevall's jird in varying reproductive condition but this trade-off depended on the quality trait considered.

During the breeding season, a major androgen-dependent protein with an apparent molecular weight of 21 kDa was isolated and purified from the seminal vesicles of three Saharan rodents (MLVSP21 from Meriones libycus, MSVSP21 from Meriones shawi, and MCVSP21 from Meriones crassus). The 21-kDa protein was isolated and purified from soluble seminal vesicle proteins of homogenate by one-dimensional polyacrylamide gel electrophoresis (SDS-PAGE). Using polyclonal antibodies directed against POSVP21 (Psammomys obesus seminal vesicles protein of 21 kDa), a major androgen-dependent secretory protein from sand rat seminal vesicles, identified previously as transgelin, we showed an immunological homology with POSVP21 by immunoblotting. These three major androgen-dependent proteins with a same apparent molecular weight of 21 kDa designated as MLVSP21 (Meriones libycus seminal vesicles protein of 21 kDa), MSVSP21 (Meriones shawi seminal vesicles protein of 21 kDa), and MCVSP21 (Meriones crassus seminal vesicles protein of 21 kDa) were localized by immunohistochemistry and identified by applying a proteomic approach. Our results indicated that the isolated proteins MLSVP21, MSSVP21, and MCSVP21 seem to correspond to the same protein: the transgelin. So that transgelin can be used as a specific marker of these rodent physiological reproduction mechanisms.

Parents may alter offspring phenotype depending on the type of environment they encounter. Parasitism is a common stressor; therefore, maternal reproductive investment could change in response to parasitic infection. However, few experiments have investigated the relationship between parasitism and maternal investment, whereas earlier field studies provided contradictory evidence. We investigated number, sex ratio, and growth of offspring in two rodent species, solitary altricial Meriones crassus and social precocial Acomys cahirinus, exposed to parasitism by fleas Xenopsylla ramesis and Parapulex chephrenis. No effect of treatment on litter size or sex ratio of a litter was found in either rodent species. Flea parasitism was found to affect pre-weaning body mass gain in M. crassus, but not in A. cahirinus pups. Furthermore, it appeared that female M. crassus invested resources into their offspring differently in dependence of litter size. In small litters (1–3 offspring), pups from infested females gained more body mass before weaning than pups from uninfested mothers. However, this trend was reversed in females with large litters indicating that parasitized females have a finite amount of resources with which to provision their young. Thus, M. crassus mothers parasitized by fleas seemed to receive some sort of external cues (e.g., stress caused by infestation) that prompted them to alter offspring provisioning, depending on species-specific possibilities and constraints. Therefore, parasites could be a mediator of environmentally induced maternal effects and offspring provisioning may have adaptive value against parasitism.

SUMMARYWe studied the effect of density of larvae on pre-imaginal development in 2 flea species (Xenopsylla conformis and Xenopsylla ramesis) parasitic on 2 desert rodent species (Dipodillus dasyurus, adult body mass 20 g and Meriones crassus, 80 g). We predicted a decrease in duration of development with an increase in density of larvae. In general, in both flea species, duration of larva-to-pupa development decreased with an increasing larval density. In addition, this stage of development was longer in male fleas and in fleas from parents fed on D. dasyurus. The effect of larval density on larval development was manifested mainly when parent fleas fed on D. dasyurus. Duration of pupation decreased with increasing larval density only in offspring of fleas fed on G. dasyurus. In both fleas, pupation was longer in males. The effect of parent host on duration of pupation was found in X. ramesis only (longer if the host was M. crassus). Resistance of newly emerged fleas to starvation depended mainly on parent host species. Young X. conformis survived longer if their parents fed on D. dasyurus, whereas young X. ramesis survived longer if their parents fed on M. crassus. It was also found that (a) an individual flea that spent more time as a larva also spent more time as a pupa and (b) longer larval development resulted in a shorter time that a newly emerged flea was able to survive when starved.

SUMMARYWe tested the hypothesis that a negative fitness–density relationship exists in haematophagous ectoparasites. We studied the effect of flea density on the number of blood meals necessary for starting oviposition and egg production in Xenopsylla conformis and Xenopsylla ramesiswhen exploiting two rodent hosts, Meriones crassus and Gerbillus dasyurus. The number of blood meals taken by a flea prior to first oviposition was similar in both flea species but was dependent on flea density and differed significantly between hosts. When parasitizing G. dasyurus, females of both flea species required a similar number of blood meals to start oviposition, independent of density. By contrast, fleas on M. crassus at higher densities needed less blood meals than at lower densities. Egg production of female fleas differed significantly between flea and host species and was affected by flea density. X. ramesisproduced more eggs than X. conformis. When parasitizing G. dasyurus, density did not affect the number of eggs produced by X. conformis, however, when on M. crassus, this flea produced significantly less eggs at the highest density. The number of eggs produced by X. ramesis at high densities was significantly lower than at low densities when it parasitized either host species. Results of this study demonstrated that reproductive success of fleas was density dependent and, in general, decreased with an increase in density. However, the effect of density on reproductive performance was manifested differently on different host species.

Zoonotic cutaneous leishmaniasis (CL) caused by Leishmania major occurs widely in Iran, where several species of rodent serve as the parasite's 'reservoir' hosts. In an attempt to identify the rodent hosts in the Larestan region, which lies in the Fars province of southern Iran (where the incidence of human CL has been rising), 32 rodents (20 Tatera indica, eight Meriones crassus, four Gerbillus sp.) were caught and checked for leishmanial infection. Using two detection methods (the microscopical examination of stained tissue smears and the culture of tissue samples) and a PCR to identify any leishmanial parasites detected, L. major was identified in six of the rodents caught: two male T. indica from Alamarvdasht, two female T. indica from Lamerd, and two females of the genus Gerbillus (one caught in Lamerd and one in Lar). Although the samples were too small to prove that M. crassus is not a significant host of L. major in Larestan, they were large enough to indicate that T. indica and members of the genus Gerbillus serve as reservoir hosts of L. major in the region. Tatera indica appears to be an important host of L. major across much of Iran but this appears to be the first time that the genus Gerbillus has been found to be involved in the epidemiology of CL in the country.

(1) The responses of body temperature ( T b ) daily rhythms of short photoperiod (8L:16D) acclimated fat jirds Meriones crassus , a nocturnal xeric burrowing species, to beta (propranolol, 4.5 mg/kg) and alpha (prazosine, 1 mg/kg) adrenergic blockade were studied. (2) The results of our study show that beta blockade significantly ( p T b values during the dark phase (24:00 and 06:00 h) and shifted the acrophase. (3) Alpha blockade significantly ( p T b values during the dark phase (24:00 h) but significantly ( p T b during the light phase (12:00 h). (4) These responses are similar to those obtained for two different diurnal species inhabiting arid environments and differ from those of the nocturnal golden hamster.

Summary 1. We hypothesized that food availability, and therefore body condition, of a rodent host, Meriones crassus , affects egg production and survival, and development time of preimago and adults of the first generation of the flea Xenopsylla ramesis . 2. Egg production was significantly higher in fleas parasitizing underfed than control animals. 3. Food availability for hosts affected survival of eggs and larvae produced by fleas on these rodents, but did not affect survival of pupae. More than twice the number of eggs from fleas on food-limited hosts survived than those from fleas on control rodents. Highest larval survival was recorded in fleas on rodents with 30% of maintenance energy intake. 4. Survival of new generation imagos was lowest in fleas from parents on hosts with the highest food limitation. By contrast, survival of parent fleas was highest on hosts offered 30% of maintenance energy intake. 5. Time of egg and larval development was longest on hosts consuming 30% of energy requirements for maintenance. By contrast, there was no difference in time to emergence in pupae from flea females on rodents from different treatments. Survival time under starvation of imago of the first generation was shortest in offspring of fleas that parasitized M. crassus offered the minimal amount of food. The opposite was true for parent fleas. 6. The results suggest nutritional and/or energetic cost of host resistance, measured as host-mediated parasite fitness loss, as well as possible adaptive stress-induced immunosuppression.

We studied dietary intakes and time budgets in two desert gerbillids, Psammomys obesus, a diurnal herbivore, and Meriones crassus, a nocturnal granivore. P. obesus was offered fresh leaves of Atriplex halimus while M. crassus was offered millet seeds and Atriplex halimus, mainly as a source of water. We predicted that the (1) nocturnal rodent will feed mainly at night and the diurnal rodent mainly during the day; and (2) the herbivore consuming a relatively low energy diet will spend more time feeding than the granivore consuming a relatively high energy diet. The latter prediction was confirmed in that P. obesus spent more time feeding than M. crassus. Number of feeding sessions in M. crassus was the same as in P. obesus but each feeding session was shorter. However, the former prediction was only partially confirmed. Feeding during the dark phase was significantly longer than the light phase in the nocturnal M. crassus, as predicted; but feeding did not differ between diel phases in the diurnal P. obesus. The large amount of forage required by P. obesus necessitated consumption throughout the light and dark phases at the same rates of intake.

Summary 1 Fleas Xenopsylla conformis and Xenopsylla ramesis parasitize the rodents Meriones crassus and Gerbillus dasyurus. Previously reported isodar analysis of host selection suggested that at low density, X. conformis parasitizes M. crassus only, but with an increase in flea density, G. dasyurus is also parasitized. Xenopsylla ramesis at low density parasitizes both hosts equally, whereas at high density prefers M. crassus. The ultimate cause of underlying these patterns was suggested to be differential fitness reward of parasitism on a particular host species, while the mechanism can be adaptive host selection by fleas. 2 To justify the suggested fitness–density relations, we studied reproductive success in X. conformis and X. ramesis feeding on either M. crassus or G. dasyurus. We hypothesized that reproductive success would differ between two host species for each flea species. 3 Xenopsylla conformis parasitizing M. crassus produced more eggs than when parasitizing G. dasyurus, whereas time of oviposition and larval hatching did not depend on host species. In contrast, egg production in X. ramesis did not differ between host species. However, fleas fed on M. crassus needed fewer bloodmeals, oviposited earlier and hatching of their larvae took less time than those of fleas fed on G. dasyurus. 4 Patterns of egg production and development time in both fleas were consistent with the hypothesis that their between-host distribution arose from adaptive host selection strategy.

Summary 1 Non-reproducing Sundevall Jird (Meriones crassus) females (body mass = 84 g; n = 51), with a mean average daily metabolic rate (ADMR) of 88 kJ day−1, were divided into three groups: high (H), medium (M) and low (L) ADMR. It was hypothesized that ADMR is related to reproductive rate and predicted that the H group could support a higher reproductive rate than the L group. It was also hypothesized that allocation of energy differs with ADMR level and predicted that the H group would use mainly the reallocation of metabolizable energy to compensate for an increased energy demand for reproduction whereas the L group would increase their metabolizable energy intake markedly. To test the hypotheses, the females were mated and, in those that had litters (n = 32), changes in body mass and metabolizable energy intake were determined and milk production was estimated during 15 days of lactation. Litter size, offspring mass and growth rate were determined for pups. 2 Body mass of dams, litter size and body mass of young at birth were similar among ADMR groups. However, milk production was 42% higher and litter mass at 15 days was significantly greater in the H than in L group, supporting our first hypothesis. All females were in negative energy balance during lactation. Mobilization of body energy reserves increased with litter size but was similar among ADMR groups. In addition, the increase in metabolizable energy intake of lactating females above that of non-reproducing females was similar among ADMR groups and therefore the second hypothesis was rejected. 3 ADMR was reduced by 23% during lactation and milk energy was only 30% of total metabolizable energy invested in milk production in all females. It is concluded that lactating M. crassus used a combination of reallocation of energy and increased metabolizable energy intake during lactation. The efficiency of offspring production did not differ among ADMR groups and therefore a high ADMR has an advantage when food is abundant, whereas a low ADMR has an advantage when food is sparse.

Variation in mammalian auditory bulla size has been linked to environmental conditions, and has even been claimed to provide a habitat-specific survival value. Enlarged bullae are typically shared among species adapted to living in arid habitats. Previous studies suggest that jirds also exhibit this adaptive enlargement of the bulla. However, such claims are based on the observation on a limited number of specimens, and thus they provide no quantitative support for this hypothesis. Therefore, we tested this hypothesis using a combination of geometric morphometrics and multivariate statistical techniques on a large sample of two jird species that exhibit a wide and partially overlapping geographical (and hence climatic) range, i.e., Meriones crassus (Sundevall, 1842) and M. libycus (Lichtenstein, 1823). A total of 485 intact skulls of populations originating from Africa to the eastern Iranian Plateau were analysed. The covariation between auditory bulla shape and several geoclimatic variables was explored using the two-block partial least-squares method. To some degree, the results seem to support the hypothesis that morphological variation in the auditory bulla is, indeed, correlated with geoclimatic variation. However, this finding cannot be generalised at several levels, hence refuting the hypothesis of convergent correlations between geoclimatic conditions and bulla morphology. Species-specific differences were found at different levels, suggesting that if local responses are present, they may reflect interactions with phylogenetic constraints.

Burrows of Meriones crassus were studied in two habitats in the central Negev Desert. Burrows in the loess habitat were more complex than in the sand habitat. To measure the burrow microclimate, artificial burrows were constructed in natural habitats and equipped with temperature and relative humidity data loggers. Daily fluctuations of temperature and relative humidity in burrows were much lower than those of ambient air. Average burrow temperatures were higher than air temperatures. The difference between average daily ambient and burrow temperatures was higher in the sand habitat than in the loess habitat. Average relative humidity in burrows was lower than relative humidity of ambient air throughout the year in the sand habitat and in summer and autumn in the loess habitat. In winter and spring, relative humidity of burrow air was significantly higher than that of ambient air. The presence of nest material in the burrow chamber increased relative humidity. Laboratory experiments demonstrated that the presence of an animal in the burrow chamber increased soil water content at the chamber's floor and this effect persisted for at least two months after removal of animals.

Jirds (genus Meriones) are a diverse group of rodents, with a wide distribution range in Iran. Sundevall’s jird (Meriones crassus Sundevall, 1842) is one such species that shows a disjunct distribution, found on the Iranian Plateau and Western Zagros Mountains. Morphological differences observed between these two populations, however, lack quantitative support. Morphological differences between geographical populations of Meriones crassus were analysed and compared with those of the sympatric M. libycus. Similarities in the cranial morphology of these species were found, e.g. in a relatively large and inflated bulla. A two-dimensional geometric morphometric analysis was done on the skull of 275 M. crassus and 220 M. libycus from more than 70 different localities in their distribution range. Results confirm cranial differences between specimens of M. crassus from the Western Zagros and those from Africa and Arabia, mainly at the level of the relative size of the tympanic bulla, that were significantly correlated with the annual rainfall and elevation. Moreover, the study supports the hypothesis that the Western Zagros specimens are both a geographically and phenotypically distinct group compared to the other Iranian M. crassus specimens, suggesting that the former might be a distinct species.

Seasonal body mass change in rodents could be due to: (1) an adaptive strategy that reduces energy requirements during unfavorable seasons and (2) a response to fluctuations in food resources. We measured seasonal body mass changes and habitat distribution in four Negev highland rodent species, Meriones crassus, Gerbillus dasyurus, G. henleyi, and Acomys cahirinus.Analyses were done to determine the effect of habitat, season, sex, and residence on body mass. The species exhibited differences in body mass (a)among seasons, except for A. cahirinus, and (b) between sexes, except forG. henleyi. G. dasyurus was the only species in which body mass was influenced by habitat. During summer and winter, M. crassus and G. henleyimade widespread movements whereas G. dasyurus and A. cahirinus did not. Meriones crassus exhibited regular dispersal when most individuals moved to the same area and changed habitats seasonally, while movements ofG. henleyi occurred non-directionally within the same habitat. In the three ger...

The spatial and temporal compositions of rodent communities in habitats of the Badia region of north-eastJordan were investigated between 1996 and 1997. Live grid-trapping and spot-lighting techniques wereemployed to estimate rodent densities. Sixteen environmental variables including soil content, vegetationcover and relief were recorded within the study sites. TWINSPAN was used to derive six habitat classesbased on the similarity of their rodent communities. These were hammada, harrat, marab, wadi and twotypes of sand dunes. The derived classifications were similar to the original categorization of habitat typesbased on ground-truthed observations of the sites selected from satellite imagery. Multivariate statisticalanalyses (TWINSPAN and DECORANA) revealed three major rodent groups in relation to local habitattypes: (1) petrophiles: Gerbillus dasyurus, Acomys russatus and Meriones tristrami; (2) open hammada-dwelling species: Jaculus jaculus, Gerbillus henleyi and Meriones crassus; (3) psammophiles: Merioneslibycus, Gerbillus nanus and Gerbillus cheesmani. Species richness was highest in marabs and lowest in redsand dunes. Species diversity (Hill’s index) was highest in sand dunes and lowest in red sand dunes. Rodentbiomass was highest in sand dunes and lowest in wadis. CANOCO showed rodent community compositionto be correlated with vegetation parameters and soil content. TWINSPAN grouping and DECORANAordination of rodent species provides some evidence for habitat preference, size disparity and competitionas mechanisms of resource partitioning facilitating coexistence.Key words: rodents, desert-living, environments, petrophiles, psammophiles

Effects of energy intake on the estrous cycle of the desert gerbillid, Sundevall's jird (Meriones crassus; 80 g; n=22) were studied. Females were offered either maintenance or below maintenance levels of millet seeds and ad lib. Atriplex halimus leaves and stems; drinking water was not available. Vaginal smears were used to determine sexual stage. We hypothesized that the estrous cycle ceases at low levels of energy intake and commences when sufficient energy is available. Females lost body mass linearly with a decrease in metabolizable energy intake. Estrous cycle averaged 4.46 d at maintenance energy intake but increased to an average of 7.81 d at 70% of maintenance energy intake. A cessation of the cycle occurred at an energy intake below 70% of maintenance requirements, which resulted in a body mass loss of more than 1% per day. More variability in the length of the different stages of the cycle was found with lower levels of energy intake. When offered ad lib. millet seeds and A. halimus (n=14), recovery to the normal cycle was attained within 10 d by 43% of the females and within 16 d by the rest of the females. Recovery time was longest in females that previously had the lowest energy intake. We concluded that the estrous cycle of M. crassus is sensitive to energy intake. With restricted energy intake, the estrous cycle and reproductive activities cease but can be restored with provision of adequate energy. This strategy ensures that reproduction occurs when conditions of food availability and body condition of the females are favorable.

Plant selection, energy intake, and digestibility were studied in nonrepro- ducing Gerbillus henleyi (10 g; n = 9), Gerbillus dasyurus (24 g; n = 6), and Meriones crassus (90 g; n = 9). These gerbils coexist in the Negev Desert Highlands, have similar dietary habits (being primarily granivores), and do not require drinking water, but they differ greatly in body mass. Each species was offered different levels (0% and -40% and 80% of maintenance energy requirements) of millet seeds and ad libitum fresh vegetation consisting of Atriplex halimus, Moricandia nitens, Zygophyllum dumosum, Lycium shawii, Anabasis articulate, and Thymelaea hirsuta, the dominant plants in the area inhabited by the rodents. Drinking water was not available. We hypothesized that: (1) smaller animals would be more dependent than larger animals on highly digestible food items such as seeds, and (2) smaller animals would be more selective than larger animals for highly digestible and energy-rich plant parts. The minimum levels of millet seeds needed to maintain body mass were 97%, 94%, and 36% of maintenance energy requirements for G. henleyi, G. dasyurus, and M. crassus, respectively. Therefore, G. henleyi was the most dependent on seeds, and M. crassus the least, supporting hypothesis 1. At similar levels of seeds consumed, apparent digestibilities of dry matter (DMD) and energy of the total diet were highest for G. henleyi. In the absence of seeds, vegetation DMD averaged 88% in G. henleyi and 70% in M. crassus, yet G. henleyi lost body mass, as a percentage, twice as fast as M. crassus. The three rodent species were selective in consuming vegetation and made similar choices. A. halimus and M. nitens were preferred, comprising -48%, 64%, and 67% of total plant dry matter consumption in G. henleyi, G. dasyurus, and M. crassus, respectively. Plant species not selected were relatively low in water and protein contents and were high in phenolic compounds and condensed tannins compared to preferred species. Gross energy, ash, and fiber levels did not appear to affect selectivity. Selection of plant parts within each plant species, as indicated by the leaf: stem (L:S) ratio, differed among rodent species. The L:S ratio for A. halimus was 4.8, but the L:S ratios ingested were 1.7, 4.0, and 7.4 in G. henleyi, G. dasyurus, and M. crassus, respectively, indicating selection of stems by G. henleyi, selection of leaves by M. crassus, and basically no selection by G. dasyurus. The ratio of seed: green vegetation (S:G) intake was highest in G. henleyi and lowest in M. crassus. A similar inverse rela- tionship between body mass and S:G ratio within seasons was found in other Old World and New World free-living granivorous desert rodents.

Gerbillus henleyi (10 g) and Meriones crassus (73 g), coexisting desert rodents, consumed similar proportions of seeds (0.84-0.88 of total dry-matter intake) when offered millet seeds and the plant Hammada salicornica ad lib. However, based on differences in body size, we predicted that the smaller G. henleyi would consume a more energy-rich diet than M. crassus. This occurred (digestible energy of 19.3 versus 17.2 kJ g -l dry matter) as a result of differences in energy intake of H. salicornica. G. henleyi consumed this plant after shredding it, whereas M. crassus consumed it in toto.