الفهرس 
Ecological StudiesOnly 14 pages are availabe for public view
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Abstract
Field as well as laboratory studies were carried out on two Egyptian sympatric insectivorous bat species, namely, the Tomb Bat, Taphozous perforatus and the Lesser Mouse-tailed Bat, Rhinopoma hardwickii, inhabiting Saqqara area, Giza Province, Egypt. The study area is located some 17 km south of Giza town and some 40 km southwest of Cairo. Studies were conducted for 24 months extending from January 2012 to December 2013, inclusive, and included both ecological and toxicological studies. The results of the present work are of special interest to wildlife conservationists, agricultural and pest control specialists, public health authorities, and authorities responsible for the control of environmental pollution. A total of 331 individual bats (211 individuals of T. perforatus and 120 individuals of R. hardwickii) was collected throughout the study period. Ecological and population studies included such aspects as age determination of individual bats, sex-ratio, reproductive cycle, age structure, and body weight changes. The determination of relative ages of both bat species depends on measuring the lengths of their forearms. The lengths of digits number three and number five proved to be less useful for arranging individual bats into relative age-groups. However, the relationship between forearm lengths and digital lengths in both bat species are represented by mathematical equations.The study of sex-ratios indicates that males of both bat species slightly outnumbered females in the total sample collected during the study period. These ratios showed noticeable differences between sub-adults and adults of both bat species. The seasonal changes in sex-ratio were more prominent in T. perforatus than in R. harwickii. The reproductive strategy of T. perforatus depends on storing sperms by females after copulation in late autumn months followed by delayed pregnancy, delivery and lactation in late winter, spring, and early summer month. Females thus pass through the following three broad reproductive phases: 1. sexual quiescence (in late summer and early autumn months), 2. insemination and incubation of sperms (in late autumn and early winter months), and 3. delayed pregnancy, delivery and lactation (in late winter, spring, and early summer months). The delivery of young is suggested to occur in late spring. Each pregnant female gives birth to only one young. Reproductively active males of T. perforatus were only collected in late autumn months and those of R. hardwickii, were collected in late autumn and winter months.
The study of the age structure indicates that adults outnumbered sub-adults in the total populations as well as in both sexes of the two bat species with the exception of female R. hardwickii. The high percentage of adult females of T. perforatus, in contrast with the low percentage of sub-adults, reflects the small litter size in this bat species and in other bats in general. The seasonal changes in the age structure showed some differences between the two bat species and were generally related to the reproductive cycle of bats. Age pyramids indicate that sub-adults as well as old adults form low percentages of the population of T. perforatus. The low percentage of sub-adults indicates that the population growth rate of bats is low. The body weight of both sexes of both bat species clearly increased with the increase of individual ages. Males had highest mean body weights in autumn months (months of sperm production) while females had highest mean body weights in spring and summer months (months of pregnancy and lactation). For the purpose of toxicological analyses, samples of the liver and kidney were dissected out of the adult individuals of both sexes of the two bat species throughout the second year of the study period. These samples were analyzed for heavy metal and insecticide residues. Samples of the liver and kidney were also dissected out of the Egyptian Fruit-bat, Rosettus aegyptiacus, collected from the same study area in spring season of the same year.The concentrations of 14 heavy metals were determined in the three bat species to the nearest ppm. According to their concentrations, heavy metals were grouped into four classes in the case of liver samples (˂1 μg/g tissue, ≥1- ˂10 μg/g tissue, ≥10-˂100 μg/g tissue, and ≥100 μg/g tissue), and into three classes in case of kidney samples (≥1- ˂10 μg/g tissue, ≥10-˂100 μg/g tissue, and ˃100 μg/g tissue).
Seasonal, organ, and sex and species differences in heavy metal concentrations have indicated that the liver of the three bat species had higher concentrations of most elements than the kidney throughout the study period. The results indicated that the total heavy metal concentrations in the liver were generally higher in T. perforatus in three seasons (winter, spring and summer), and in R. hardwickii in only one season (autumn). It was observed, on the other hand, that R. hardwickii tended to accumulate higher renal toxic metal concentrations than T. perforatus in all seasons of the study period. In spring, it was clearly noticed that the total metal concentration in the liver of Rousettus aegyptiacus was lower than that in Taphozous perforatus, but slightly higher than that in Rhinopoma hardwickii. The total metal concentration was lower in the kidney of Rousettus aegyptiacus compared to that in the kidney of both insectivorous bat species. Guano samples were also collected from the floor of roosting
caves of the insectivorous bats and analyzed for metal
concentrations. The results indicated that the metal concentrations in guano were higher than that in tissues of both bat species in all
seasons.
Liver and kidney of only the tomp bat and the Egyptian fruit-bat were analyzed for the presence of pesticide residues. These residues were observed in very low concentrations in both sexes of the tomb bat. The highest general mean concentration in the liver was recorded for p,p’-DDE, while the highest general mean concentration in the kidney was recorded for PCB138. No residues of p,p’-DDD, and sulfur were detected in the kidney, and hexachlorobenzene was not detected in the liver and kidney. No pesticide residues were detected in the kidney and liver tissues of both sexes of the Egyptian Fruit-bat.