Teruaki Uchida

Effects of temperature on development and growth in the tick, Haemaphysalis longicornis

As a part of ecological studies onHaemaphysalis longicornis, the effects of controlled temperatures (12, 15, 20, 25 and 30°C; ∼ 100% RH) on development and growth of the tick were investigated and the critical low temperature for each stage in the life cycle was estimated. As the temperature became low, the periods of preoviposition, oviposition, egg hatching (incubation) and moulting were prolonged. At 12°C, however, oviposition, egg hatching and moulting of the larva and nymph did not occur. The critical low temperatures for oviposition, egg hatching (developmental zero) and larval and nymphal moulting which were calculated theoretically from the regression equations, were 11.1, 12.2, 10.2 and 11.8°C, respectively. The temperature also affected the egg productivity and hatch-ratio. The number of deposited eggs per mg of body weight decreased markedly at 15°C, and the hatch-ratio was lowered with dropped temperatures.

Formation of the microtubule bundle and helical shaping of the spermatid in the common finch, Lonchura striata var. domestica

Spermiogenesis in the common finch with special reference to the role of microtubules constituting the microtubule bundle was examined. Microtubules first appear in a loosely grouped cluster which helically surrounds the spherical nucleus. Concurrently with the formation of a single helical bundle of microtubules, the nucleus first assumes a helical shape. With a change in microtubular array, the ridge surface of the nuclear helix becomes flattened and depressed; the gyres of the nuclear helix increase in number. During helical shaping of the acrosome, the microtubule bundle is closely associated with the posterior one gyre of the acrosomal helix with the same pitch as in the nuclear helix. At the completion of acrosomal shaping, the microtubule bundle is separated from the acrosome by the Sertoli cell process. The microtubule bundle completely disappears in the mature spermatid. It is suggested that microtubules play an important role in helical shaping of the acrosome and nucleus.

Karyological Studies of two Japanese Noctule Bats (Chiroptera)

SUMMARYKaryological investigations of two Japanese Nyctalus species were made based on G- and C-banding pattern analysis. The karyotype of N. furvus (2n = 44, FN = 50) was similar to the standard karyotype of Myotis species. On the other hand, the karyotype of N. lasiopterus aviator (2n = 42, FN = 50) was characterized by having an additional large metacentric pair. By comparison of the G-banding pattern between the two Nyctalus species, it is clear that the metacentric pair of N. lasiopterus aviator has derived from the Robertsonian fusion of the two pairs (nos. 8 and 10) of N. furvus. There was also a significant difference in amount of constitutive heterochromatin between the two Nyctalus species. In N. furvus the additional heterochromatin was observed on the majority of autosomes, while in N. lasiopterus aviator a small C-band was restricted to the centromeric area of each autosome. Thus, the C-band pattern of N. lasiopterus aviator would be interpreted by assuming the decrease of heterochromatin in ...

Sperm invasion of the oviducal mucosa, fibroblastic phagocytosis and endometrial sloughing in the Japanese greater horseshoe bat, Rhinolophus ferrumequinum nippon

SummaryIn the Japanese greater horseshoe bat, Rhinolophus ferrumequinum nippon, a vast number of spermatozoa invade the oviducal epithelial cells of the caudal isthmus and become concentrated in the endometrial lamina propria of the bicornuate horns. They are subsequently phagocytised and digested by fibroblasts. Then, finally, they become deposited in the uterine lumen together with a large quantity of secretory material from the endometrial connective tissue which, prior to this event, undergoes a massive infiltration by polymorphonuclear leucocytes.

Feeding Behaviour of Three Species of Squirrels

The Japanese giant flying squirrel, Petaurista leucogenys, Japanese flying squirrel, Pteromys momonga and Asiatic chipmunk, were compared for feeding behaviour under experimental conditions. Although P. leucogenys always fed in a sitting posture on branches, it extended its forepaws effectively both laterally and ventrally. When the animal was not able to place its large body on a slender twig, it brought the twig within reach of the mouth by the forepaws, obtaining food at the tip. P. momonga and T. s. asiaticus took a hanging posture, too, and the former was more skillful in this posture than was the latter. In picking up food scattered on the floor, P. leucogenys extended the body, without shifting its hindfeet, in a wide range including its lateral side; T. s. asiaticus got food in a narrow range only just in front of the body, and P. momonga had an intermediate range between those of the above two species. Among the three species, the daily frequency of feeding bouts was in inverse proportion to the duration of a feeding bout; P. leucogenys had relatively long and infrequent bouts, the reverse being the case with T. s. asiaticus. Characteristics of the posture, technique and frequency of feeding in the three species were supposed to be a reflection of interspecific differences in the diet, habitat, and freedom and length of the forelimb.

Karyotypic Evolution of Two Japanese Vespertilio Species and its Taxonomic Implications (Chiroptera: Mammalia)

SUMMARYA detailed karyotypic analysis of two Japanese Vespertilio species, V. superans and V. orientalis, was made on the basis of conventional data, G- and C-band patterns. No detectable karyotypic difference was found between the two species (2n = 38, FN = 54). By comparison of G-band patterns between Vespertilio species and Ny c talus lasiopterus (2 n = 42, FN = 50), it was revealed that the four pairs (M-1, 2, 3 and 6) of six large M-autosome pairs found in Vespertilio are homologous to the four large biarmed pairs (nos. 1, 2, 3 and 8) in N. lasiopterus, and the remaining two large M-pairs (M-4 and 5) in Vespertilio have been formed by centric fusions of the four medium-sized A-pairs (nos. 5 and 9 for M-4, and nos. 6 and 11 for M-5). This indicates that Vespertilio evolved from a certain Ny c talus species, such as N. lasiopterus, having a somewhat derived karyotype (2n = 42, FN = 50).The similarity of the C-band pattern on the complements of Vespertilio species and N. lasiopterus suggests that the ka...

A Karyotypic Study on Four Species of the Indonesian Fruit-Eating Bats, Belonging to Cynopterus, Eonycteris and Macroglossus (Chiroptera: Pteropidae)

SUMMARYThe karyotypes of four Indonesian pteropid bats, Cynopterus brachyotis javanicus, C. sphinx titthaecheilus (subfamily Pteropinae), Eonycteris spelaea spelaea and Macroglossus minimus minimus (subfamily Macroglossinae), are reported. On the basis of the comparison of our data and the karyotypes of the pteropid bats studied so far, it is assumed that the common ancestor of the two subfamilies possessed the karyotype with 2n = 36, FN = 68 or near and one pair of the marker chromosomes. The karyotypic difference found in Macroglossus and Eonycteris is considered to have resulted from the combination of some changing mechanisms occurring in the four pairs of small autosomes found in the complements of Eonycteris, but not pericentric inversion alone.

Electron microscopical and biochemical studies of the major pectoral muscles of bats

Abstract The major pectoral muscles (musculus pectoralis superficialis) of two species of bats (Miniopterus schreibersi fuliginosus and Rhinolophus ferrumequinum nippon) were studied by electron microscope and quantitative determination of myoglobin were carried out. 1. 2. In the pectoral muscles of both species, numerous mitochondria and lipid droplets occur between myofibrils. 2. 3. The average myoglobin concentration is 5.58 mg/g in M. s. fuliginosus and 1.83mg/g in R. f. nippon. 3. 4. It is suggested that these differences are related to the physiological properties of the muscles needed for different types of flight.