Brains of Vespertilionids

Macromorphology and encephalization (EI) of brains were compared in 58 Vespertilionid species, brain composition in 36 species: 46 or 27 species of Vespertilioninae, 8 or 5 species of Miniopterinae, 2 species of Kerivoulinae, and 2 species of Nyctophilinae. Subfamily differences were found in the extent of the cover of the mesencephalon. It is nearly fully covered in Kerivoula papulosa (Kerivoulinae), at least half covered (by the cerebellum) in Miniopterinae, and free (completely or nearly so) in Nyctophilinae and Vespertilioninae. In relative brain size, the Kerivoulinae are highest (average EI = 130), followed by the Miniopterinae (111), Nyctophilinae (102) and Vespertilioninae (95). The higher encephalization of Kerivoulinae and Miniopterinae is accompanied by a marked increase of relative size in cerebellum and striatum, and in Kerivoulinae, in hippocampus and neocortex as well.     

The brain organization of butterflyfishes

Synopsis The encephalization indices of angelfishes (Pomacanthidae) and butterflyfishes (Chaetodontidae) are typical of advanced perciform fishes: both families lie in the upper part of the polygon of teleost indices. The chaetodontids seem to be a little more encephalized than pomacanthids. The general morphology of the brains in both families is very similar: small olfactory bulbs, large optic tectum and a cerebellum which covers the brain structures in front of it like a cap. This morphology is shared by another family of the coral reef biotope, the Acanthuridae. The histological architecture is also typical of advanced teleosts, with a cortex-like pallium, a laminated nucleus geniculatus (= pretectalis superficialis), a complex valvula cerebelli and a corpus glomerulosum with a clear neuropile centre. The quantitative analysis of the main subdivisions of the brain, either from relative volumes or from indices, shows small olfactory bulbs (microsmy) but important telencephalic and diencephalic centres, large tectal centres (vision) and large cerebellum (precise locomotion). Many of these peculiarities are shared by other fishes inhabiting coral reefs. The differences between the two families seem to be primarily correlated with food habits: the angelfishes, which are sponge-feeders and may have an overweight due to the ballast of the sponge-skeleton in their digestive tract, and which do not need either such good vision or such precise locomotion to pick up their prey, could be a little less encephalized than the butterflyfishes.     

Brain organization and evolution in subterranean mole rats

Relative brain component sizes have been analyzed in subterranean mole rats of the Spalax ehren-bergi superspecies in Israel. Our results indicate that brain size and brain component sizes may have evolved in association with specific stresses underground involving the distinct development of vocalzation, olfaction and tactile sensory communication systems all compensating for the loss of vision.     

Early hominid body weight and encephalization

The body weight of the Plio-Pleistocene hominids of Africa is estimated by predicting equations derived from the Terry Collection of human skeletons with known body weights. About 50% of the variance in body weight can be accounted for by vertebral and femoral size. Predicted early hominid weights range from 27.6 kg (61 lb) to 54.3 kg (119 lb). The average weight for Australopithecus is 43.2 kg (95 lb) and for Homo sp. indet. from East Rudolf, Kenya, is 52.8 kg (116 lb). These estimates are consistent even if pongid proportions are assumed. Indices of encephalization show that the brain to body weight ratio in Australopithecus is above the great ape averages but well below Homo sapiens. The Homo sp. indet. represented by the KNM-ER 1470, O.H. 7 and O.H. 13 crania have encephalization indices above Australopithecus despite the greater body weight of the former.     

Cranial capacity in hominid evolution

We present an analysis of cranial capacity of 118 hominid crania available from the literature. The crania belong to both the genusAustralopithecus andHomo and provide a clear outline of hominid cranial evolution starting at more than 3 million years ago. Beginning withA. afarensis there is a clear increase in both absolute and relative brain size with every successive time period.H.s. neandertal has an absolutely and relatively smaller brain size (1412cc, E.Q.=5.6) than fossil modernH.s. sapiens (1487cc, E.Q.=5.9). Three evolutionary models of hominid brain evolution were tested: gradualism, punctuated equilibrium, and a mixed model using both gradualism and punctuated equilibrium. Both parametric and non-parametric analyses show a clear trend toward increasing brain size withH. erectus and a possible relationship within archaicH. sapiens. An evolutionary stasis in cranial capacity could not be refuted for all other taxa. Consequently, the mixed model appears to more fully explain hominid cranial capacity evolution. However, taxonomic decisions could directly compromise the possibility of testing the evolutionary mechanisms hypothesized to be operating in hominid brain expansion.     

Milk composition and lactational output in the greater spear-nosed bat, Phyllostomus hastatus

Growth rates of mammalian young are closely linked to the ability of the mother to provide nutrients; thus, milk composition and yield provide a direct measure of maternal investment during lactation in many mammals. We studied changes in milk composition and output throughout lactation in a free-ranging population of the omnivorous bat, Phyllostomus hastatus. Fat and dry matter of milk increased from 9 to 21% and from 21 to 35% of wet mass, respectively, throughout lactation. Energy increased from 6 to 9 kJ · g⁻¹ wet mass, primarily due to the increase in fat concentration. Total sugar levels decreased slightly but non-significantly. Mean sugar level was 4.0% of wet mass. Protein concentration increased from 6 to 11% of wet mass at peak lactation and then decreased as pups approached weaning age. Total milk energy output until pups began to forage was 3609 kJ. Milk levels of Mg, Fe, Ca, K, and Na averaged 0.55 ± 0.26, 0.23 ± 0.2, 8.75 ± 4.17, 5.42 ± 2.11, and 9.87 ± 4.3 mg · g⁻¹ dry matter, respectively. Of the minerals studied, calcium appears to be most limiting in this species. The high degree of variability in foraging time, milk composition and milk yield between individuals at the same stage of lactation could potentially yield high variance in reproductive success among females of this polygynous species. Accepted: 23 January 1997     

Changes in milk composition during lactation in three species of insectivorous bats

Changes in milk composition are described for three species of free-ranging insectivorous bats (Myotis lucifugus, M. velifer, and Tadarida brasiliensis) from early to mid (peak) lactation. Dry matter and energy concentrations in milk increased from early to mid-lactation. In M. lucifugus and T. brasiliensis, but not M. velifer, these increases were due largely to a rise in fat concentration, since protein and carbohydrate remained relatively constant. Energy content of milk (kJ·g^-1) for each species from early through mid-lactation was related to dry matter (DM) as follows: M. lucifugus (y=0.31 DM-0.32, r ²=0.68), M. velifer (y=0.48 DM-5.08, r ²=0.99), and T. brasiliensis (y=0.37 DM-1.51, r ²=0.61). Comparison of the effect of sampling method on milk composition of T. brasiliensis indicated that fat, dry matter, and energy concentrations increased significantly from pre-dawn to prenoon samples. Relatively high fat and low water levels in T. brasiliensis milk may reflect the limited access that lactating females have to free water, as well as need to minimize mass of stored milk during long foraging trips. Conversely, lower fat concentrations and higher water levels in milk in M. lucifugus and M. velifer may relate to the propensity for colonies of these two species to roost and forage near bodies of water. In addition, differences in milk fat concentrations observed among the three species may correlate to daily suckling schedules. Females of T. brasiliensis, for example, roost apart from and suckle their young on a regular daily schedule, whereas both species of Myotis roost with their pups and appear to suckle them on demand.Abbreviations bm body mass - DM dry matter - T _a air temperature     

Human encephalization and developmental timing

Human evolution is frequently analyzed in the light of changes in developmental timing. Encephalization in particular has been frequently linked to the slow pace of development in Homo sapiens. The "brain allometry extension" theory postulates that the progressive extension of a conserved primate brain allometry into postnatal life was the basis for brain enlargement in the human lineage. This study shows that published primate and human growth data do not corroborate this model. Instead, the unique encephalization of H. sapiens is alternatively described as the result of evolutionary changes in three aspects of developmental timing. The first is a moderate extension in the duration of brain growth relative to our closest extant relatives, contrary to the view that human brain growth is drastically prolonged into postnatal life. Second, humans evolved a derived brain allometry in comparison with chimpanzees and early hominins. Third, humans (and other anthropoid primates to a lesser degree) display a significant retardation in early postnatal body growth in comparison with other mammals, which directly affects adult encephalization in our species. The rejection of the "brain allometry extension" model may require a reevaluation of the adaptive scenarios proposed to explain how human encephalization evolved.     

卷柏内生真菌多样性研究

为探究蕨类植物内生真菌的多样性,本研究采用可培养方法分离江西龙虎山和广东丹霞山的岩壁常见蕨类植物——卷柏的内生真菌,结合形态特征和ITS序列进行菌株鉴定、研究多样性。结果表明：从1 080个组织块中,共分离出234株菌株,卷柏内生真菌的总定殖率为18.98%,总分离率为21.67%。根据分离频率,毛壳菌属Chaetomium（26.50%）、青霉属Penicillium（18.38%）、棒束孢属Isaria（11.97%）、曲霉属Aspergillus（9.42%）为优势属。不同居群地春季卷柏的内生真菌多样性存在差异,龙虎山的分离率为34.72%,而丹霞山仅为6.39%,其优势属也不尽相同。对龙虎山不同季节的卷柏内生真菌多样性研究表明,春季的分离率为34.72%,高于冬季的23.89%,春、冬两季之间的真菌类群相似性系数仅为0.39,差异显著。研究结果将有助于进一步揭示丹霞地貌地区蕨类植物内生真菌物种组成及其影响因素。     

A new method for quantifying encephalization in the growing individual

Here we describe a new method for quantifying encephalization in the growing individual and provide a worked example of the methods. The new method is based on the use of conditional SD scores derived from brain and body growth references. These encephalization SD scores control for age, sex and body size effects on brain size, and therefore, control for the confounds associated with allometry as well as growth differences between the brain and body and between the sexes. The methods also control for distribution skewness. Encephalization SD scores derived from pre- and post-natal data may be directly compared and changes in SD score over time assessed. These methods may be applied to a broad range of data where relative size during growth is to be quantified. Derived SD scores may also be applied to correlation and regression analyses where statistical relationships with other variables are of interest.     

Progressive und regressive Hirngrößienveränderungen bei Equiden

Progressive and regressive changes of brain size within Equidae From Hyracotherium to Equus brain size increased eightfold independently from body size. In domestication brain size is reduced; within mammals the amount of reduction depends on cephalization. Species with high cephalization show much more reductions than those with low cephalization. Among the ancestors of domesticated mammals wild horses have the highest cephalization level; reduction of brain size of more than 30% in domesticated horses could be expected. The size of the brain case of domesticated horses is only 14 % smaller than in wild Przewalski horses. We think that populations of the wild Przewalski horses have been crossbreeds between wild and domesticated animals. There is no difference in size of the brain case capacity and the brain weight between the Przewalski horses from zoological gardens and domesticated horses. This may be due to further crossbreeding between Zoo-Przewalski horses and domesticated horses and to artificial selection.     

Morphology, echolocation and foraging behaviour in two sympatric sibling species of bat (Tylonycteris pachypus and Tylonycteris robustula) (Chiroptera: Vespertilionidae)

We studied the wing morphology, echolocation calls, foraging behaviour and flight speed of Tylonycteris pachypus and Tylonycteris robustula in Longzhou County, South China during the summer (June–August) of 2005. The wingspan, wing loading and aspect ratio of the two species were relatively low, and those of T. pachypus were lower compared with T. robustula . The echolocation calls of T. pachypus and T. robustula consist of a broadband frequency modulated (FM) sweep followed by a short narrowband FM sweep. The dominant frequency of calls of T. pachypus was 65.1 kHz, whereas that of T. robustula was 57.7 kHz. The call frequencies (including highest frequency of the call, lowest frequency of the call and frequency of the call that contained most energy) of T. pachypus were higher than those of T. robustula , and the pulse duration of the former was longer than that of the latter. The inter-pulse interval and bandwidth of the calls were not significantly different between the two species. Tylonycteris pachypus foraged in more complex environments than T. robustula , although the two species were both netted in edge habitats (around trees or houses), along pathways and in the tops of trees. Tylonycteris pachypus flew slower (straight level flight speed, 4.3 m s⁻¹) than T. robustula (straight level flight speed, 4.8 m s⁻¹). We discuss the relationship between wing morphology, echolocation calls, foraging behaviour and flight speed, and demonstrate resource partitioning between these two species in terms of morphological and behavioural factors.     

浙江磐安种子植物区系的特征分析

磐安约有野生种子植物 1 44科 ,62 7属 ,1 2 98种 (包括种以下分类单位 )。其中世界成分的属 67个 ,占总属数的 1 0 .69% ,热带属 2 2 7个 ,占 36.2 0 % ,温带属 32 1个 ,占 5 1 .2 0 % ,中国特有属 1 2个 ,占 1 .91 %。磐安气候温暖湿润 ,植物种类丰富 ,古老、孑遗、珍稀植物多 ,单种属和少种属占有较大比重 ;优势科、优势属明显 ,优势科 34个 ,共含有 393属 ,776种 ,分别占总属数总种属的 62 .7% ,70 .3% ,优势属 1 0个 ,共含有 1 44种 ,分别占总属数总种数的 1 .6% ,1 1 .1 % ,其中樟科、壳斗科等是该区系的表征科 ;植物分布类型多样 ,地理成分复杂 ,温带成分和热带成分占优势 ,是亚热带分布的北缘 ,与世界各地有广泛的联系     

翼手目动物的特殊生殖策略：精子贮存

介绍了精子贮存现象在翼手目动物中的分布、产生的原因、精子贮存的部位、贮存后的受精能力、精子长期贮存的机制及贮存过程中的免疫问题,并对将来的研究方向进行了展望。     

扁颅蝠的栖息地及最北分布

扁颅蝠(Tylonycteris pachypus)被列入《中国濒危动物红皮书》,是我国最小的蝙蝠之一。因其栖息于竹子中的特殊习性而备受人们关注。研究显示,扁颅蝠选择有虫蚀的粉单竹(Lingnania chungin)竹林栖息(洞口平均为43.79 mm×11.94 mm)。1997年8月在四川南充市金城山(N30°40′,E106°18′)发现的扁颅蝠,为其地理上最北分布。     

广西扁颅蝠与褐扁颅蝠的食物选择

2002年3～10日在广西南宁地区的宁明县和龙州县,用超声波监测和网捕法确定扁颅蝠与褐扁颅蝠的捕食区,在捕食区内用粘捕法调查潜在的食物量;用粪便分析法确定食物组成。在宁明县和龙州县扁颅蝠和褐扁颅蝠的潜在食物量都是以双翅目昆虫为主(45．93％以上),其次为鞘翅目(12．59％以上)和膜翅目(7．47％以上);但双翅目、膜翅目在两地差异显著。宁明县扁颅蝠的食物组成以双翅目(40．33％)和膜翅目(38．46％)为主,鞘翅目(16．07％)次之;龙州县扁颅蝠和褐扁颅蝠食物组成中以膜翅目(63．37％,62．34％)为主,其次为双翅目(21．57％,29．62％)、鞘翅目(11．59％,5．96％);对比两地扁颅蝠的食物组成发现,膜翅目和双翅目差异极显著。对比食物组成与潜在食物量发现,两种蝙蝠对膜翅目为正选择,对其他目负选择或无选择,均为选择性捕食者。