CHANGES IN ACTIVITY OF DGLUCOSE-6-PHOSPHATE: NADP AND 6-PHOSPHO-D-GLUCONATE: NADP OXIDOREDUCTASES IN RELATION TO LIGNIFICATION OF BAMBOO

D-Glucose-6-phosphate: NADP oxidoreductase (glucose-6-phosphatedehydrogenase; EC 1.1.1.49 [EC] ) and 6-phospho-D-gluconate: NADPoxidoreductase (6-phosphogluconate dehydrogenase; EC 1.1.1.44 [EC] )were found to be present in immature bamboo. Optimal pHs ofthe glucose-6-phosphate- and 6-phosphogluconate dehydrogenaseswere found to be 8.0 and 8.5, respectively. Both enzymes were demonstrated to be NADP-specific and NADPcould not be replaced by NAD. Fructose-6-phosphate was indirectlyutilized after convrsion to glucose-6-phosphate by glucose-6-phosphateisomerase coexisting in the enzyme preparation. Pattern of enzyme activity and of respiratory breakdown of glucose-1-¹⁴Cand glucose-6-¹⁴C were investigated in connection with lignificationof bamboo and discussed in comparison with sugar metabolismof fungi-infected plant tissues. As for the changes in the enzymeactivity with growth of bamboo, it was recognized that therewas a tendency that the activity of both enzymes increased andwas maintained at a certain level even in the aged tissues.In addition there was a drop of the C₆/C₁ ratio toward the tissuesof lower parts containing considerable amount of lignin andthis phenomenon was the same as that observed in pentose phosphatemetabolism of fungi-infected plant tissues. (Received September 5, 1966; )     

Breeding season, courtship behaviour, and territoriality of White and Japanese Wagtails Motacilla alba and M. grandis

The breeding ecology of White and Japanese Wagtails, Motacilla alba and M. grandis , was studied along a river in central Japan. The home ranges of the two species greatly overlapped along the river, but no interbreeding occurred. M. grandis spent more time on the river than M. alba and defended territories there. M. alba used the river as part of the entire home range, and did not defend the river areas as territories. Singing activity and breeding started earlier in M. grandis than in M. alba. The early breeding of M. grandis was related to the lack of moulting in spring, less necessity for pair formation due to the existence of pairs in the winter, and the greater dependency on larval than on adult insects. Songs were very different between the two species. The bowing display that preceded the pre-copulation display was found only in M. alba. During the pre-copulation display, male M. grandis lifted both wings above the horizontal while male M. alba drooped both wings. The pre-copulation display of M. grandis was similar to that of Large Pied Wagtails M. maderaspatensis in India, suggesting a closer relationship of the two species than to M. alba.     

Network analysis of potential migration routes for Oriental White Storks (<Emphasis Type="Italic">Ciconia boyciana</Emphasis>)

From 1998 through to 2000, we satellite-tracked the movements of 13 Oriental White Storks (Ciconia boyciana) on their autumnal migration in order to identify their important stopover sites for preserving links from the Russian Far East breeding sites to the wintering sites in south-eastern China. New analytical methods of satellite tracking data were employed to derive robust information on the locations of stay sites, the number of stopovers made during migration, and the distance traveled without making stopovers. Based on the derived information, we modeled a stay site network as an abstraction of the storks potential migration routes from their breeding sites to wintering sites. Using network analysis techniques, we explored how the loss of stopover sites could affect the connectivity of potential migration routes. The results suggested that if the seashore stopover sites facing Bohai Bay in eastern China were lost, the storks wintering sites along the Yangtze River in south-eastern China would be isolated. Among the seashore stopover sites, Jiantuozhi Gley Mire (39.185°N, 118.627°E), located on the northern seashore of Bohai Bay, was considered particularly important for migrating storks, because it was used every year by the storks we tracked. If conservation needs of this critically located site fail to be addressed, the stay site network of storks can create weak links in the chain of migration and, if broken, storks will have great difficulties in completing their autumnal migration.     

Effect of neighbour visibility on nest attendance patterns of Barn Swallows Hirundo rustica in loose colonies

To assess the benefits of nesting at a site hidden from neighbours in a loosely colonial species, the Barn Swallow Hirundo rustica, we carried out two field experiments, obstruction removal and mirror placement, both replicating a situation in which a nest is made visible from another nest. Under manipulated conditions in both experiments, females increased the length of time they stayed at their nests during the egg‐laying and late incubation stages, while males extended their duration of stay during the egg‐laying and early nestling stages in mirror placement experiments only. The results suggest that Barn Swallows conceal their nests to reduce fitness costs imposed by neighbours nesting in view and that hiding the nest can reduce the amount of time spent guarding the nest during certain stages of the breeding period.