Gerbillus Dasyurus Research Articles

Rodent Populations Recovering from Fire in an East Mediterranean Woodland*

Fire in woodlands causes a dramatic decrease in rodent populations. The aim of this study was to detect rodent succession in three different management regimes of a post-fire habitat on Mount Carmel: (1) a control area of mixed woodlands of burnt pine and oak; (2) a mixed burnt woodland in which the burnt pine trees were cut and left in situ; and (3) a mixed burnt woodland in which burnt pines were cut and removed from the plot. Two plots in an unburnt mixed woodland were used as controls. The first invader species observed in the post-fire habitats were Mus macedonicus, which was the most abundant species in all burnt plots, Gerbillus dasyurus, which was mainly trapped in plots where the burnt pine trees were removed, and Meriones tristrami, which was mainly trapped in plots where the burnt pine trees were left in situ. The highest species diversity was recorded in the control plots of the burnt pine and oak woodland. In these burnt control plots the field mice (Apodemus) of both species reappeared. However, the numbers of trapped A. flavicollis were rather higher than of A. mystacinus. It is thus assumed that the invading species will be replaced by the originial woodland rodent species through resilience. *This study is dedicated in the memory of our colleague Mr. D. Banin.

Predator - Prey Relationships: Rodent - Snail Interactions in the Central Negev Desert of Israel

We investigated the effects of increasing rodent (Acomys cahirinus and Gerbillus dasyurus) predation efficiency on their population density and the population of their prey, the desert snail (Trochoidae seetzenii). The study was carried out on a rocky hillslope in the Central Negev Desert, Israel. Rodent predation on snails is limited by the number of shelters for rodents in the area. In most natural conditions, more shelters are found on the upper than on the lower slope. We introduced artificial shelters along the slope. We then censused the number of rodents, snails, and of eaten snails for five years

Water Intake in Two Coexisting Desert Rodents, Acomys cahirinus and Gerbillus dasyurus

The common spiny mouse, Acomys cahirinus ( X body mass = 48 g), and Wagner's gerbil, Gerbillus dasyurus ( X body mass = 33 g), are omnivorous Old World rodents that coexist in rocky habitats in the deserts of Israel. They differ in their diets in that A. cahirinus consumes proportionately more snails and animal matter than G. dasyurus and G. dasyurus consumes proportionately more seeds than A. cahirinus . Rodents were offered seeds and either water ad lib., ca. 50% of ad lib. total water intake, or denied water. Both species were able to maintain steady state body mass on both ad lib. and 50% ad lib. water. Furthermore, both species lost body mass when denied water. However, the daily rate of loss of body mass of G. dasyurus was slower than that of A. cahirinus both in absolute (0.72 and 1.72 g) and in relative (10.9 and 21.9% body mass/g0.54) terms. Dry matter digestibility and metabolizable energy from seeds were similar between species on the ad lib. and 50% ad lib. water treatments and both species combined averaged 90.9% of dry matter and 88.8% of gross energy, respectively—these values were similar to those found for granivorous rodents in general.

The burrowing habits of desertic Rodents Jaculus jaculus and Gerbillus dasyurus in the Shaumari Reserve in Jordan

Etude de la configuration des terriers dans la reserve de Shaumari.Les deblais des terriers, la surface de sol occupee, la longueur et le volume des galeries, le nombre de culs-de-sac, le nombre de nids, le nombre de chambres de reserve et la composition de la nourriture ont ete notes

Thermoregulation and metabolism of Wagner's Gerbil ( Gerbillus dasyurus): A rock dwelling rodent adapted to arid and mesic environments

The nocturnal rock-dwelling gerbil ( Gerbillus dasyurus) is widely distributed in the steppe deserts of the Arabian peninsula. The O 2 consumption V ̇ O 2 of this species in the thermoneutral zone is only 64% of the V ̇ O 2 of a 27.6 g mammal as predicted Brody (1945). The intake of digestible dry matter is relatively low correlating with the V ̇ O 2 values. The thermal conductance value for G. dasyurus is similar to that predicted for a rodent with a body of 28 g (Bradley and Deavers, 1980), but lower than that measured for other rodents occurring in arid habitats (Haim, 1984). Low heat conductance compared to desert rodents and increased V ̇ O 2 when exposed to cold appear to be important adaptations of G. dasyurus in cold mesic environments.

40. Testosterone production by testicular tissue of the camel ( Camelus dromedarius) during the breeding season

Enzymatic reactions involved in androgen biosynthesis in Gerbillus dasyurus were investigated in vitro using testicular homogenates. The activity of 20α-hydroxysteroid oxidoreductase was significantly high, but that of the 17,20-lyase and 17β-hydroxysteroid oxidoreductase appeared relatively low. Double label experiments where [3H]5-ene 3β-hydroxysteroids and [14C]4-en-3-oxosteroids were incubated simultancously as substrates, indicated that testosterone is preferentially synthesized via the 4-ene route. The activity of 17β-hydroxysteroid oxidoreductase observed in testes of Gerbillus was the lowest of all the rodents compared. The activity of this enzyme decreased after laboratory rodents were acclimatized to an elevated ambient temperature (35°C, 30–50% relative humidity). The relevance of the enhanced activity of 20α-hydroxysteroid oxidoreductase associated with the low biosynthetic rate of testosterone in desert rodents is discussed.

Helminths of birds and mammals of Israel. VII. - Pneumospirura rodentium n. sp. (Pneumospiruridae - Thelazioidea).

Pneumospirura rodentium a lung parasite of Gerbillus dasyurus and Meriones crassus is described. P. hainanensis Wu and Hu, 1938 and Metathelazia servalis Chabaud and Biocca, 1950, have cephalic structures resembling those of P. rodentium. But the three species can be differentiated by the size of spicules, their localization, hosts and geographical distribution.

Androgen biosynthesis by testicular tissue of the desert rodents, Acomys cahirinus and Gerbillus dasyurus.

Summary. Androgen biosynthesis was investigated in the desert rodents, Acomys cahirinus and Gerbillus dasyurus. In these experiments, radioactive substrates were incubated with testicular homogenates and the metabolites formed were identified. The accumulation of 5-ene-3β-hydroxysteroids suggested that the biosynthesis proceeded preferentially by the 4-ene route. This was confirmed by double-label experiments where [3H]5-ene-3β-hydroxysteroids and [14C]4-en-3-oxosteroids were employed. The preferred route for the production of the major androgens appears to be pregnenolone → progesterone→ 17α-hydroxyprogesterone→androstenedione→testosterone. In addition, these species were characterized by enhanced activity of 20α-hydroxysteroid oxidoreductase and low activity of 17β-hydroxysteroid oxidoreductase, a phenomenon also observed in the laboratory rat and mouse acclimatized to a hot environment. Some parameters of desert ecology are briefly described.

Enzymes of androgen biosynthesis in the desert mouse Gerbillus dasyurus

Enzymatic reactions involved in androgen biosynthesis in Gerbillus dasyurus were investigated in vitro using testicular homogenates. The activity of 20α-hydroxysteroid oxidoreductase was significantly high, but that of the 17,20-lyase and 17β-hydroxysteroid oxidoreductase appeared relatively low. Double label experiments where [ 3H]5-ene 3β-hydroxysteroids and [ 14C]4-en-3-oxosteroids were incubated simultancously as substrates, indicated that testosterone is preferentially synthesized via the 4-ene route. The activity of 17β-hydroxysteroid oxidoreductase observed in testes of Gerbillus was the lowest of all the rodents compared. The activity of this enzyme decreased after laboratory rodents were acclimatized to an elevated ambient temperature (35°C, 30–50% relative humidity). The relevance of the enhanced activity of 20α-hydroxysteroid oxidoreductase associated with the low biosynthetic rate of testosterone in desert rodents is discussed.