Does calcium constrain reproductive activity in insectivorous bats? Some empirical evidence for Schreibers’ long-fingered bat (Miniopterus schreibersii)

Insects are a poor source of dietary calcium and since they are seasonally abundant, it has been suggested that calcium availability may play a significant role in controlling the timing of reproduction in insectivorous bats. To assess the possible role of dietary calcium, we have measured bone calcium concentrations in female and male long-fingered bats (Miniopterus schreibersii) through a full reproductive cycle. The results indicate that winter was not a period of calcium stress and, therefore, that seasonal changes in insect abundance and dietary calcium availability are not a satisfactory explanation for the occurrence of delayed implantation in the long-fingered bat. Bone calcium concentrations of females did not differ significantly throughout pregnancy, indicating that the insects available in winter and early summer were sufficient to meet the calcium demands of pregnancy. Lactating females had the lowest bone calcium concentrations of all specimens, supporting the suggestion that lactation is indeed a period of severe calcium stress in aerial insectivores. We conclude that parturition is probably timed so that lactation coincides with the period of maximal insect abundance and corresponding dietary calcium availability

Seasonally monoestrous reproduction in the molossid bat, Tadarida aegyptiaca from low temperate latitudes (33°S) in South Africa

A histological study of reproduction in Egyptian free-tailed bats (Tadarida aegyptiaca) Irom the Eastern Cape Province of South Alrica (c. 33°S) showed that females were seasonally monoestrous. Copulation, ovulation and lerlilizalion occurred in August, at the encf of winter, and births in December, after a four-month pregnancy. These results are compared with those of other molossid bats from tower latitudes in Africa. We conclude that the monoestrous habit of the Egyptian Iree-tailed bat at 33°S may be due to its relatively long pregnancy, and to the short summer period during which minimum temperatures are high enough to ensure an abundance of nocturnal flying insects

Ecological correlates of relative brain size in some South African rodents

Relative brain size (size of the brain once body size effects have been removed) has been calculated for 16 species of rodent from South Africa and is shown to vary with six species having a positive RBS (that is a brain larger than expected) and 10 a negative RBS. Arboreal species such as Paraxerus cepapi and Graphiurus murinus and omnivores (G. murinus) have relatively larger brains than do the fossoriai root eaters such as Cryptomys hottentotus and terrestrial follivores (Otomys irroratus). It is suggested that the relatively large brains can be linked to the complex behavioural patterns necessary for locomotion in three dimensions and for utilization of a food resource such as insects that is randomly distributed in time and space. The three sciuromorph rodents (Xerus inauris, Paraxerus cepapi and Pedetes capensis) have very different life styles but all have a positive RBS and it is suggested that a relatively large brain may be a characteristic of the suborder

Book Reviews

Book Review 1Book Title: Reproductive Energetics in MammalsBook Authors: A.S.I. Loudon & P.A. Racey (Eds.)Zoological Society of London Symposia 57, 1987 Clarendon. Press, Oxford. 371 pp.Book Review 2Book Title: Classification of Southern African MammalsBook Authors: J.A.J. Meester, I.L. Rautenbach, N.J. Dippenaar & C.M. BakerTransvaal Museum Monograph No.5. 359 pp.Book Review 3Book Title: Pesticide impact on stream fauna with special reference to macroinvertebratesBook Author: R.C. Muirhead-ThomsonCambridge University Press, 1987. 275 pp.Book Review 4Book Title: Evolution of sex determining mechanismsBook Author: James J. BullBenjamin-Cummings Publ. Company / Addison-Wesley Publishing Group, JohannesburgBook Review 5Book Title: The evolutionary ecology of ant-plant mutualismsBook Author: Andrew J. BeattieCambridge University Press 182 pp.Book Review 6Book Title: The Ecology of SexBook Authors: P.J. Greenwood & J. Adams Edward Arnold, London, 1987. 74 pagesBook Review 7Book Title: The Dinosaur Heresies - a revolutionary view of dinosaursBook Author: Robert BakkerPublished by Longman Scientific and Technical, 1987Book Review 8Book Title: Molecular Biology of the GeneBook Authors: Watson, Hopkins, Roberts, Steitz & WeinerVolumes I and II (Fourth Edition) (Benjamin/Cummings. Menlo Park); Addison-Wesley Publishing Group. Johannesburg 1163 pp.Book Review 9Book Title: Evolutionary BiologyBook Author: Eli C. MinkoffAddison-Wesley Publishing Company, Massachussets, 1983. 627pp.Book Review 10Book Title: An ecosystem approach to aquatic ecology. Mirror Lake and its environmentBook Author: Gene E. Likens (Ed.)Springer-Ver1ag, New York. xiv - 516 pages; 197 figuresBook Review 11Book Title: The Physiological Ecology of SeaweedsBook Authors: C.S. Lobban, P.J. Harrison & M.J. Duncan Cambridge University press, Cambridge, 1985. 242 pagesBook Review 12Book Title: Principles of ecologyBook Authors: R.J.Putman & S.D. WrattenCroom Helm, London, 1984. 388 pages

Book Reviews

Book Review 1Book Title: Pheromones of Social BeesBook Author: John B. FreeChapman & Hall, 1987. 218 pp.Book Review 2Book Title: Insects - PlantsBook Authors: V. Labeyrie et alDr. W. Junk Publishers, The Hague, 1987. 459 pp.Book Review 3Book Title: The Ecology of Woodland Rodents: Bank voles and wood miceBook Authors: Edited by J.R. Flowerdew, J. Gurnell & J.H.W GippsThe Zoological Society of London. Clarendon Press, Oxford, 1985. 418 pp.Book Review 4Book Title: Visual behavior in salamandersBook Author: Gerhard RothSpringer-Verlag, Berlin, 1987. 301 pp.Book Review 5Book Title: Digestive Physiology and Nutrition of MarsupialsBook Author: Ian D. HumeMonographs on Marsupial Biology. Cambridge University Press, 1982. 256 pp.Book Review 6Book Title: Neurobiology and Behavior of HoneybeesBook Authors: Edited by Randolf Menzel & Alison MercerSpringer-Verlag, 1987.334 pp.Book Review 7Book Title: Ecology and Productivity of an African Wetland SystemBook Author: G.A. EllenbroekDr W. Junk Publishers, Dordrecht, 1987. 267 pagesBook Review 8Book Title: Biological Surveys of Estuaries and Coasts Estuarine and Brackish Water Sciences Association HandbookBook Authors: Edited by J.M. Baker & W.J. WolffCambridge University Press, 1987. 449 pp.Book Review 9Book Title: Caste Differentiation in Social InsectsBook Authors: Edited by J.A.L. Watson, S.M. Okot-Kotber & C.H. NoirotPergamon Press, Oxford, 1985. 399 pp.Book Review 10Book Title: Sistematica, filogenia y biogeografia de la subfamilia Gibbiinae (Coleoptera, Ptinidae)Book Author: Xavier BellésTreballs del Museu de Zoologia, 1985, No.3, Barcelona. 94 pp.Book Review 11Book Title: A Biologist's Advanced MathematicsBook Author: D.R. CaustonAllen & Unwin, London 326 pp.Book Review 12 Book Title: Reproduction in Mammals: 5 Manipulating reproductionBook Authors: Edited by C.R. Austin & R.V. ShortCambridge University Press, London, New York, New Rochelle, Melbourne, Sydney. 235 pp.Book Review 13Book Title: Vertebrate Fetal MembranesBook Author: Harland W. MossmanMacmillan press, 1987. 383 pp.Book Review 14Book Title: Avian Physiology (Fourth edition)Book Author: Edited by P.O. SturkieSpringer-Verlag, New York, 1986. 516 pp

Female reproductive anatomy and development of ovarian follicles in Miniopterus fraterculus

The uterus of Miniopterus fraterculus (Thomas & Swan 1906) is bicornuate and asymmetrical, the right uterine horn being larger than the left in parous and nulliparous females. Ovarian and uterine function is asymmetrical; 94% of observed ovulations originated in the left ovary and all implantations occurred in the right uterine horn. Growth and development of ovarian follicles follow the typical eutherian mammalian pattern. The preovulatory Graafian follicle differs from that of most hibernating verspertilionids in that the cumulus oophorus is relatively small. Two types of follicular atresia occur. The first type, in which the stratum granulosum degenerates before degeneration of the oocyte, occurs in multilaminar follicles. The second type occurs in primary and early secondary follicles and is characterized by the oocyte showing the first signs of regression

Monthly changes in the female reproductive organs and the reproductive cycle of Myotis tricolor (Vespertilionidae : Chiroptera)

No Abstract

Reproduction in the Cape horseshoe bat (Rhinolophus capensis) from South Africa

Structure of the reproductive organs and the processes of spermatogenesis and follicular development are described and are· similar to those described for other members of the genus Rhinolophus. The reproductive cycle of the Cape horseshoe bat is characterized by spermatogenesis between October and May (spring to autumn) with sperm released to the cauda epididymis in April and May. At this time the females are in oestrus or submaximal oestrus but copulation and ovulation are delayed until August and September (the end of winter hibernation). Between May and September spermatozoa are stored in the cauda epididymis where they show no positive association with the epididymal epithelium. Parturition occurs in November and December after a three to four month gestation

Life history of the springhare (Pedetes capensis) from a strongly seasonal environment in the Eastern Cape Province of South Africa

The life history of the springhare (Pedetes capensis, Forster, 1778) at 33°S, in the Eastern Cape Province of South Africa, was characterized by continuous, aseasonal and asynchronous reproduction. Females were monotocous and consecutive pregnancies were separated by a non pregnant period (30–50 days) similar in length to the period of lactation. Young were relatively large at birth (8% of adult body weight) but were altricial and only emerged from the burrow at weaning. Towards the end of lactation, many females mated again (20% of all females were both lactating and in early pregnancy) and annual fecundity was probably two but never more than three. For a rodent, albeit a large one, this is a very slow rate of reproduction and we propose that the ricochetal locomotion (jumping on the hind legs) and semi-fossorial life style of the springhare will have resulted in decreased juvenile and adult mortality, and increased longevity, and that these factors have shaped the evolution of the life history of the springhare.Keywords: reproduction, Rodentia, ricochetal locomotio

Changes in the abundance of cells in the anterior pituitary gland and the possible roles of luteinizing hormone, prolactin and progesterone in the control of delayed implantation in the straw-coloured fruit bat (Eidolon helvum)

Eidolon helvum (Megachiroptera) is a large frugivorous bat found in equatorial and tropical Africa. The reproductive cycle is characterized by a three-month period of delayed implantation and the total length of pregnancy may be as much as 10 months. A histochemical study of the gonadotrophs and mammotrophs of the anterior pituitary, in conjunction with assays of LH-like, progesterone-like and prolactin-like  immunoreactivity in the plasma suggest that during delayed implantation the gonadotrophs were inactive while the mammotrophs were active and plasma PRL-like immunoreactivity high. We interpret this as indicating that, in the straw-coloured fruit bat, implantation was inhibited by high levels of prolactin and, as such, the endocrine control of delayed implantation may be quite different from that described for other mammals.Key words: Megachiroptera, reproduction, mammotroph, gonadotroph