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91.
Masahito Natori 《Primates; journal of primatology》1994,35(2):167-176
The craniometrical variations among marmosets on the eastern coast of Brazil or theCallithrix jacchus group (C. jacchus, C. penicillata, C. kuhli, C. geoffroyi, C. flaviceps, andC. aurita) were analyzed to test various hypotheses for the arrangement of the species and phylogenetic relationships ofC. kuhli andC. flaviceps. Q-mode correlation coefficients and principal component analysis were employed to extract important shape factors from the
craniometrical data. On this basis, the shape distances among the eastern Brazilian marmosets were found to be larger than
those between the marmosets which are recognized as distinct species. This evidence supports the hypothesis that the members
of theC. jacchus group are distinct species.C. kuhli shows the strongest resemblance toC. geoffroyi within theC. jacchus group.C. flaviceps is the most similar toC. aurita in its cranial shape. These findings indicate thatC. kuhli is most closely related toC. geoffroyi, whileC. flaviceps is toC. aurita. 相似文献
92.
Joanie McKeon Eric Slade Donald A. R. Sinclair Niansheng Cheng Mitchell Couling Hugh W. Brock 《Molecular & general genetics : MGG》1994,244(5):474-483
Mutations in severalPolycomb (Pc) group genes cause maternal-effect or zygotic segmentation defects, suggesting thatPc group genes may regulate the segmentation genes ofDrosophila. We show that individuals doubly heterozygous for mutations inpolyhomeotic and six otherPc group genes show gap, pair rule, and segment polarity segmentation defects. We examined double heterozygous combinations ofPc group and segmentation mutations for enhancement of adult and embryonic segmentation defects.Posterior
sex combs andpolyhomeotic interact withKrüppel
2 and enhance embryonic phenotypes ofhunchback andknirps, andpolyhomeotic enhanceseven-skipped. Surprisingly, flies carrying duplications ofextra sex combs (esc), that were heterozygous for mutations ofeven-skipped (eve), were extremely subvital. Embryos and surviving adults of this genotype showed strong segmentation defects in even-numbered segments. Antibody studies confirm that expression ofeve is suppressed by duplications ofesc. However,esc duplications have no effect on other gap or pair rule genes tested. To our knowledge, this is only the second triplo-abnormal phenotype associated withPc group genes. Duplications of nine otherPc group genes have no detectable effect oneve. Expression ofengrailed (en) was abnormal in the central nervous systems of mostPc group mutants. These results support a role forPc genes in regulation of some segmentation genes, and suggest thatesc may act differently from otherPc group genes. 相似文献
93.
本文新建立盲走螨属agilis群并限定了该群的主要特征,归纳了世界上已描述的8种,其中分布于我国的3种,此外描述了3个新种。 相似文献
94.
95.
Defence and development in a gregarious leaf-mining beetle 总被引:1,自引:0,他引:1
HANS DAMMAN 《Ecological Entomology》1994,19(4):335-343
Abstract.
- 1 The gregarious larvae of the chrysomelid beetle Microrhopala vittata mine the leaves of goldenrods (Solidago spp.). These mines serve both as food and as shelter for the larvae.
- 2 Life-table data and experiments indicated that mine initiation and moves to secondary mines represented especially vulnerable stages during larval development. Leaf mines effectively protected M.vittata against predators in the field.
- 3 Field experiments indicated that larvae hatching from larger clutches of eggs stood a greater chance of surviving to pupation, primarily because larvae hatching in groups proved more successful at initiating leaf mines. Once inside the leaf mine, however, larvae feeding in large groups attained lower adult masses, and were more likely to abandon the natal mine and did so earlier in development because large groups more rapidly destroyed a leaf.
96.
Allison C. Alberts 《Zoo biology》1994,13(5):479-490
Depending on spatial requirements and the distribution of key resources in the environment, social behavior among lizards varies from defense of exclusive territories to the establishment of dominance hierarchies. In captivity or under conditions where dispersal is not possible, dominance hierarchies often emerge in species that are otherwise territorial. This review explores some of the morphological, behavioral, and hormonal determinants of social status in male lizards and how these may lead to differential reproductive function in dominant and subordinate individuals. Emphasis is placed on the importance of population density, local resource dispersion, and the composition and stability of social groups in promoting hierarchical behavior. Results of these studies have ramifications for several aspects of zoo management, including exhibit design, choice of animals to be housed together, provision of resources in space and time, and orientation of enclosures within captive breeding facilities. © 1994 Wiley-Liss, Inc. 相似文献
97.
Many studies have reported on the dental status of elderly patients. The results demonstrate consistent differences between normative and perceived needs in addition to varying levels of awareness of dental education among carers. This review article attempts to integrate a range of social factors which must be considered if holistic and comprehensive care is to be delivered to elderly patients. 相似文献
98.
99.
Karen B. Strier Francisco D. C. Mendes José Rímoli Adriana O. Rímoli 《International journal of primatology》1993,14(4):513-526
We monitored one group of muriquis, or woolly spider monkeys (Brachyteles arachnoides), over a 9-year period at Fazenda Montes Claros, Minas Gerais, Brazil. The group grew from 22 to 42 individuals due to the births of 21 surviving infants. Eight immigrations involving immature females were offset by emigrations and disappearances. The home range of the group expanded as the group size increased. The group traveled as a cohesive unit during the first 6 years of the study, but recently it has begun to show greater tendencies to fission temporarily into smaller subgroups. Six adult males from the other muriqui group at this site have simultaneously increased their associations with the main study group. These observations indicate that the group is in a state of transition which may lead, ultimately, either to its division into two smaller units or to a more fluid social structure. 相似文献
100.
Polygynous groups of de Brazzas monkeys (Cercopithecus neglectus) were observed in the Kisere Forest Reserve between December 1987 and March 1989. Total number of contact hours was 528. Three troops numbered 11, 13, and 16 monkeys. Three solitary adult males were seen. All troops had a single adult male, at least three adult females, and juveniles. Five births occurred in the course of the study. Home range varied from 4.1 to 6 ha, and flooded areas of the forest were heavily used. This species was only found near rivers and spent more than 50% of the time below 5 m. Daily path length ranged from 330 to 1001 m. The de Brazza's monkeys were mainly frugivorous, but leave and invertebrates also formed a substantial part of the diet. Other guenons avoided de Brazza's, which did not join polyspecific interactions. 相似文献