Evolution of nectarivory in phyllostomid bats (Phyllostomidae Gray, 1825, Chiroptera: Mammalia)

Background  

Bats of the family Phyllostomidae show a unique diversity in feeding specializations. This taxon includes species that are highly specialized on insects, blood, small vertebrates, fruits or nectar, and pollen. Feeding specialization is accompanied by morphological, physiological and behavioural adaptations. Several attempts were made to resolve the phylogenetic relationships within this family in order to reconstruct the evolutionary transitions accompanied by nutritional specialization. Nevertheless, the evolution of nectarivory remained equivocal.     

Karyological study of four Japanese Myotis bats (Chiroptera,Mammalia)

Karyological investigations of four Japanese Myotis species were made based on Gand C-banding pattern analysis. It was revealed that the four species, M. nattereri, M. hosonoi, M. frater kaguyae and M. macrodactylus have all 2n=44 and their karyotypes are, excepting one chromosome pair, identical each other. The only difference in their karyotypes was found on the morphology of the chromosome no. 5. A minute acrocentric (A) was observed in M. nattereri, and a polymorphic (A) and an (M^h) which is a minute metacentric with totally heterochromatic arm was found in M. hosonoi. In M. f. kaguyae, pair no. 5 was a small submetacentric with a totally heterochromatic long arm (SM^h). Polymorphic (SM^h) and (M) which is a small metacentric derived from (SM^h) by a pericentric inversion was seen in M. macrodactylus. Such morphological differentiations of no. 5 were interpreted by assuming an increase of constitutive heterochromatin and also an inversion. The evolutionary pathway in the genus Myotis is assumed to be as follows: (A)(M^h)(SM^h)(M). This assumption was supported by the geographical evidence that the species with the (A) type no. 5 pair is widely distributed in the whole world but the others are restricted to Asia (M^h type) or only to Japan (SM^h and M types).     

广东7 种蝙蝠的核型研究

对采集于广东的4 科7 种蝙蝠进行了核型分析,它们的核型分别是:犬蝠(Cynopterus sphinx)2n =34,FN= 58;印度假吸血蝠(Megaderma lyra)2n = 54,FN = 104;大耳双色蹄蝠(Hipposideros pomona)2n = 32,FN =60;中蹄蝠(H. larvatus)2n = 32,FN = 60;大卫鼠耳蝠(Myotis davidii)2n = 46,FN = 52;大黄蝠(Scotophilus heathi)2n = 36,FN = 54;南长翼蝠(Miniopterus australis)2n =46,FN = 50。其中大耳双色蹄蝠和大卫鼠耳蝠的核型为首次报道,犬蝠、印度假吸血蝠、中蹄蝠、大黄蝠和南长翼蝠的核型为中国第一次报道。     

Karyology of eight species of bats (Mammalia: Chiroptera) from Hainan Island,China

Karyotypes and chromosomal data are presented for eight bat species representing two families (Rhinolophidae and Vespertilionidae) from Hainan Island, China. The species investigated were Rhinolophus lepidus (2n = 62, FN = 60), R. pusillus (2n = 62, FN = 60), R. affinis (2n = 62, FN = 60), R. sinicus (2n = 36, FN = 60), Myotis horsfieldi (2n = 44, FN = 52), Pipistrellus abramus (2n = 26, FN = 44), Miniopterus australis (2n = 46, FN = 50) and M. schreibersii (2n = 46, FN = 50). The karyotype of Rhinolophus lepidus is reported for the first time.     

Key morphofunctional transformations in the evolution of bats (Mammalia,Chiroptera)

Study on the morphology and morphogenesis of wing membranes in bats has revealed some peculiarities in their structure and development. Understanding the embryogenesis of these animals, as well as attraction of data obtained on their molecular genetics and paleontology, allows one to single out some factors that could have initiated evolutionary modifications in development programs. A scenario of the key morpho-functional transformations in the forelimbs during the evolution of chiropterans is given.     

A phylogenetic supertree of the bats (Mammalia: Chiroptera)

We present the first estimate of the phylogenetic relationships among all 916 extant and nine recently extinct species of bats Mammalia: Chiroptera), a group that accounts for almost one-quarter of extant mammalian diversity. This phylogeny was derived by combining 105 estimates of bat phylogenetic relationships published since 1970 using the supertree construction technique of Matrix Representation with Parsimony (MRP). Despite the explosive growth in the number of phylogenetic studies of bats since 1990, phylogenetic relationships in the order have been studied non-randomly. For example, over one-third of all bat systematic studies to date have locused on relationships within Phyllostomidae, whereas relationships within clades such as Kerivoulinae and Murinae have never been studied using cladistic methods. Resolution in the supertree similarly differs among clades: overall resolution is poor (46.4%, of a fully bifurcating solution) but reaches 100% in some groups (e.g. relationships within Mormoopidae). The supertree analysis does not support a recent proposal that Microchiroptera is paraphyletic with respect to Megachiroptera, as the majority of source topologies support microbat monophyly. Although it is not a substitute for comprehensive phylogenetic analyses of primary molecular and morphological data, the bat supertree provides a useful tool for future phylogenetic comparative and macroevolutionary studies. Additionally, it identifies clades that have been little studied, highlights groups within which relationships are controversial, and like all phylogenetic studies, provides preliminary hypotheses that can form starting points for future phylogenetic studies of bats.     

The earliest Asian bats (Mammalia: Chiroptera) address major gaps in bat evolution

Bats dispersed widely after evolving the capacity for powered flight, and fossil bats are known from the early Eocene of most continents. Until now, however, bats have been conspicuously absent from the early Eocene of mainland Asia. Here, we report two teeth from the Junggar Basin of northern Xinjiang, China belonging to the first known early Eocene bats from Asia, representing arguably the most plesiomorphic bat molars currently recognized. These teeth combine certain bat synapomorphies with primitive traits found in other placental mammals, thereby potentially illuminating dental evolution among stem bats. The Junggar Basin teeth suggest that the dentition of the stem chiropteran family Onychonycteridae is surprisingly derived, although their postcranial anatomy is more primitive than that of any other Eocene bats. Additional comparisons with stem bat families Icaronycteridae and Archaeonycteridae fail to identify unambiguous synapomorphies for the latter taxa, raising the possibility that neither is monophyletic as currently recognized. The presence of highly plesiomorphic bats in the early Eocene of central Asia suggests that this region was an important locus for the earliest, transitional phases of bat evolution, as has been demonstrated for other placental mammal orders including Lagomorpha and Rodentia.     

Morphology and function of the shoulder joint of bats (Mammalia: Chiroptera)1

The shoulder joint of the Microchiroptera shows a remarkable morphological variation that has been studied in 20 individual bats from 15 species and 11 families. The basic morphology of the shoulder joint, with a globular humeral head and a corresponding glenoid cavity, is found in the Megachiroptera and, within the Microchiroptera, in the Rhinopomatidae. Besides this basic shoulder joint, there are two derived joint types: the derived and specialized shoulder joint with a single articular surface on the scapula and a more-or-less oblong humeral head, and the derived and specialized shoulder joint with secondary articular surfaces on the trochiter and on the dorsal aspect of the scapula. The first type of derived joint is most strikingly developed in the Mormoopidae and the Noctilionidae, the second one in the Vespertilionidae and the Molossidae. It is suggested that both types of derived shoulder joints have the functional significance of reducing the pronatory movements of the abducted forearm during the downstroke of the wing-beat cycle. This suggested function of the secondary shoulder joint is a new approach to understanding this very peculiar structure. In species with these specialized shoulder joints, the downstroke musculature is comparatively better developed and the M. serratus ant. post. div. comparatively less well developed. A hypothesis is offered to explain and combine the osteological and myological findings. Each of the derived types of shoulder joints has developed independently more than once through parallel evolution.     

Ultrastructural changes in the seminiferous epithelium of two seasonally reproducing bats (Mammalia: Chiroptera)

The Sertoli cells of the Cape horseshoe bat (Rhinolophus capensis) and Schreiber's long-fingered bat (Miniopterus schreibersii) undergo marked changes in ultrastructure related to stages in the spermatogenic cycle. The amount of lipid stored in the Sertoli cells varies annually and is at a maximum from just after spermiation to early in the following spermatogenic cycle. During spermatogenesis, the diameter of the lipid droplets decreases, reaching a minimum prior to spermiation. Sertoli cells exhibit a marked apicobasal differentiation, particularly in the vicinity of developing late spermatids, where the cytoplasm of the Sertoli cell is packed with smooth endoplasmic reticulum. The possible roles of lipid droplets and smooth endoplasmic reticulum. The possible roles of lipid droplets and smooth endoplasmic reticulum in steroidogenesis by Sertoli cells are discussed. Junctional complexes occur between Sertoli cells and spermatogonia, are apparently absent from between Sertoli cells and spermatocytes, and are restricted to the region of the developing acrosome in the spermatids. Annulate lamellae, which occur commonly in the developing germinal cells and less frequently in the Sertoli cells, may be associated with the production of microtubules, which are present in both spermatids and Sertoli cells.     

Histomorphology of the glans penis in Vespertilionidae and Phyllostomidae species (Chiroptera,Mammalia)

The penises of bats are taxonomically distinctive in size and shape. In addition, they are variable in microscopic anatomy, indicating that histomorphological studies of copulatory organs of bats may help understanding their successful reproductive strategies. We studied adult males of 13 species of vespertilionid and phyllostomid bats. Both families exhibited the basic structure of the vascular penis of mammals: the hydrostatic elements of the corpora cavernosa and the corpus spongiosum surrounding the urethra, as well as accessory cavernous tissue. Variation in the position and amount of the tissues were observed in these families. Vespertilionid bats have a small glans penis with abundant accessory cavernous tissue on the prepuce and a highly variable baculum. The baculum varied in size and morphology, even among congeneric species, such as the three Lasiurus species and the two Myotis species. Phyllostomid species possess no bacula, but vascular structures are present to produce penile stiffening, particularly on the glans. Variation in the microscopic anatomy of the phyllostomid prepuce was observed, for example, Artibeus species had accessory cavernous tissue surrounded by a tunica albuginea, but Carollia perspicillata had two bundles of striated musculature and some adipose tissue; abundant pigments were present in the prepuce of most species.     

Thermogenic capacity of three species of fruit-eating phyllostomid bats

This study evaluated the thermogenic capacity of three species of fruit-eating phyllostomid bats (Carollia perspicillata, Sturnira lilium and Artibeus lituratus) during the dry-cool and wet-warm seasons, by measuring changes in body mass, basal metabolic rate (BMR), maximal metabolic rate (MMR), nonshivering thermogenesis and shivering thermogenesis. Body mass was lower, on average, during the dry-cool season and all species of fruit-eating bats showed an increase in oxygen consumption after noradrenaline injection and after exposure to a He-O₂ atmosphere. However, the magnitude of this increase was similar in both seasons. BMR also did not vary between seasons. Although, our results showed for the first time that all three species studied were able to increase thermogenesis by both nonshivering and shivering thermogenesis, we did not find significant differences in any thermoregulatory variable measured when comparing data from the two different seasons. Probably the difference in the mean and variance of the temperature profile between seasons were not strong enough to alter the thermogenic capacity of these species. Furthermore, the use of alternative physiological (torpor) or behavioral (huddling) strategies might have alleviated the need to trigger energetic-costly thermogenic responses.     

Roosting associations of flat-headed bats, Tylonycteris species (Chiroptera: Vespertilionidae) in Malaysia

Roosting associations of Tylonycteris pachypus and T. robustula were studied in West Malaysia. Both species roosted within the internodes of one species of bamboo, but were only once found together at roost. Roosting groups, which formed before entry in the morning, were not limited in size by the dimensions of the roost site. In both species the sexes exhibited different roosting behaviour, the males tending to be solitary and the females gregarious. Seasonal variations in associations occurred correlated with the reproductive cycle. Banding demonstrated that the populations were highly mobile, that the bats frequently changed roost sites, and that the roosting associations were of an ephemeral nature.     

New distributional records of bats from the Kingdom of Saudi Arabia (Mammalia: Chiroptera)

Hipposideros caffer (Sundevall, 1846) and Miniopterus schreibersi (Kuhl, 1819) are recorded for the first time from Saudi Arabia. Additional information and second records in addition to measurements are reported for six other bats: Rhinopoma m. microphyllum, Taphozous n. nudiventris, Rhinolophus clivosus, Rhinolophus hipposideros minimus, Tadarida midas and Eptesicus nasutus. Distribution maps of Rhinolophus clivosus and Eptesicus nasutus are included.     

Social behavior of water bats (Myotis daubentonii, Chiroptera) in an open-air cage

The social behavior of Myotis daubentonii bats was studied in experimental groups kept in an openair cage. The repertoire of identification, aggressive, and friendly (integration) behaviors was described. Analysis of their frequencies showed that interactions between the animals were for the most part friendly (61.6%), while aggressive displays were rare (4.6%). Differences in behavior depending on sex and age were revealed: avoidance of contact and aggressive vocalization were observed significantly more frequently in young and adult males than in females. The bats in the experimental groups personally distinguished each other; in group 4, a two-level hierarchy was established (a dominant male vs. all other bats), which could be explained by specific conditions in the open-air cage.     

Bat flies (Diptera: Streblidae) of phyllostomid bats (Chiroptera: Phyllostomidae) from the mountainous central region of Veracruz,Mexico

Systematic Parasitology - The studies of bat flies of the family Streblidae Kolenati, 1863 in Mexico have intensified in the last five years, usually providing new geographical records of species...