In order to use Imperata cylindrica (Chigaya) for the conservation and creation of the
environment, current studie son Imperata cylindric ain taxonomy, autoecology, phytosociology,
weed science, agrostology etc. are reviewed and discussed. Imperata cylindrica is a harmful
weed widely distributed from the tropical zone to the temperate zone of the world.
In Japan, the range of the species is from Okinawa to Hokkaido. The speciesis divided into
two varieties based on the presence or absence of hairs on the node of culm. One is var.
koenigi iand the other is var. cylindrica .Imperata cylindric atype grassland are classifie dinto
five phytosociologica lclasses ,Miscanthetea sinesis, Glehnietea littorali sV,iticetea rotundifoliae
,Artemisietea principis and Chenopodietea. Imperata cylindric agrassland belonging to
Miscanthetea sinensis are developed on embankment slopes, river terraces, roadside along paddy
fields etc. where weeding by cutting is carried out two or three times a year. This weeding
grassland is reported as a new community , Imperata cylindrica― Erigeron annuus community
which is characterized by the presence of Erigeron annuus, Ixeris dentata et al. It seems that
this community is available as soil binder on embankment slopes, a model of wild flowers for
landscaping and as grassland biotope
Fluvial terraces distributing extensively along the Hidakahorobetsu and Motoura Rivers in
southern Hidaka, Hokkaido were investigated by the tephrochronological and geomorphological
method to reveal their formative periods and processes. Based on the data obtained and on
the river profile sreconstructed from terrace surfaces and the present river-bed, the change in
the river response to sea-level and climatic change during the Late Quaternary was discussed,
focusing on the period from 20 to 60 kyr.B.P.
The oviposition behaviors and breeding habits of two rhynchitid weevil species, Involvulus
apertus and /. singularis are described and illustrated. The larval morphology of the
latter species is also illustrated.
Shrub species Symplocos coreana is the common host plant, the young leaves of which
are utilized by the two weevils in different ways.
The female of I. apertus lays eggs in the leaf midrib without cutting. Its larvae bore
into the midrib and stem of the leaf. In the case of I. singularis, the female cuts the
stem before and after oviposition. Its larva makes a mine on the leaf. The leaf-mining larva
is recorded for the first time in the subtribe Rhynchitina.
The trap-nes ttechniqu ei scommonly used to investiga ttehe life-histo raynd behavior of
wasps and bees rentin gin plant stems or pre-existin gholes in wood. This study intends
to discus sth eusefulnes sof thi stechniqu efor evaluatin genvironmental-informati oinn local
areas, using tube-rentin gwasp and bee richnes sas an indicato rof natura lcondition sW.e
analyzed richnes sof tube-rentin gwasp and bee in the four differen ttypes of loca lareas;
new town area, urban area, rural areas in Sanda city. The results are as follows, l) In
new town area tube-rentin gwasp and bee decreased their number of individua lasnd species
richness, as compared with rural areas. 2) The wasps and bees had not been trapped at
the center zone of urban area and they were trapped only in the flagmented forest of
the area. 3) Eumenid wasps, which are large wasps preyin gon leaf-feedin gcaterpillars,
decreased especial ltyhei rnumber of individua lin new town and urban areas .On the other
hand, the small wasps preying on small wandering spiders, such as Trypoxylon and
Auplopus, were dominant groups in those areas. We may conclude that anaysis
of tube-renting wasp and bee richness is useful for estimating of natural conditions in
the local area.
Utilization patterns of trap-nests by some aculeate species were studied at the secondary
growth forest on the hilly area of Sanda City, Hyogo Prefecture, using bamboo stems as
trap-nests. A total of 30 trap-sites at five block locations were selected. They were layed
at intervals (2, 5, 10, 20 and 40 m) along the summit of the hill. Each block was arranged
40 m apart its neighboring blocks. Traps were exposed in a field situation from late May
to early December. Five species were obtained from these trap-nests: Anterhynchium flavomarginatum,
Chalicodoma sculpturali sD,ipogon sp. and Orancistroceru sdrewseni.
Among these, Auplopus sp. was the most frequent occupant of trap-nests in terms of the
number of trap-sites, stems used, and brood cells produced. The mean number of stems
utilized per trap-site increased with between-trap-distance in C. sculpturalis, in contrast
to Auplopus sp. which did not show such trait sin stem utilizati opnatterns. A simila rtendency
was also found in the number of brood cells produced per trap-site. These differences may
arise due to factors such as, effective area of trap-nest, foraging range, abundance of
resources, etc. All species preferred the middle and large sized tubes (more than 6 mm
in diameter) , except Dipogon sp. Several problems are discussed here concerning the application
of trap-nest techniques to environmental evaluation.
In order to clarify the effects of cutting frequency on growth, floristic composition, the
number of species, species diversity, life-form and biomass of the grassland dominated
by Imperata cylindrica var. koenigii on embankments, field experiments were conducted at
the Naka river in Tokushima Pref. from 1989 to 1992. Six experimental plots differing in
cutting frequency and season were set in the grassland. In the plots of no cutting and one
cutting every two years, the coverage of Imperata cylindric avar. koenigi ireduced, three years
after experiments had been started. Especially, in the plot of no cutting, the dominant
species had changed from Imperata cylindrica var. koenigii to Miscanthus sinensis. In a
plot of two cuttings (June, October) per year, the number of species and the species
diversity increased. Seasonal change was distinctly recognized in the floristic
composition except in plots of no cutting and one cutting every two years. Early-summer
aspect was characterized by the appearance of Agropyron tsukushiense var.
transiens et al. and the autumn aspect was characterized by the appearance
of Setaria glauca et al.
The Yaeyama Islands have been called the province of poetry and song since ancient times.
The islands are a treasury of folklore that has attracted many scholars for many years. The
islands are rich in folk songs that deal, humorously or ironically, with the small animals
living near human habitats. Among the innumerable songs about crabs in particular, the
' amparunumidagaama yunta' song is most popular. Amparu is a mangrove tideland located
about 10 km northwest of Ishigaki City and is a paradise for coastal fauna and flora. The
song describes the morphological appearances and behavioral characteristics of 15 species
of small crabs at Amparu, and personifies them in a manner unique to the genre of yunta
songs in the Yaeyama Islands. There is still some uncertainty about the identities of the
crabs in the song. To try to identify the species, we studied the folkzoological context of
the song in the vicinity of Amparu on Ishigaki Island.