The effect of a summer flood on the density of caddisfly (Trichoptera) in the middle reaches of the Shinano River, Japan

We investigated the response of caddisfly species assemblages in the middle reaches of the Shinano River to a flood that occurred in mid July 2006. Prior to the flood (on Day -22) the population density of total benthic caddisflies was 8,266.7 ± 2,392.1 individuals m-2. After the flood, by Day 11, the population density had decreased to 55.6 ± 55.6 individuals m-2. By Day 65, the density of caddis species had recovered to nearly the same level as that recorded before the flood, particularly in the case of Hydropsyche orientalis Martynov, the most abundant benthic species. By Day 65 the larvae of this species had reached pre-flood levels. On Day 40 it was noted that the larval population was dominated by final instars, but by Day 65 early instar larvae were dominant and downstream drift consisted mainly of second instars. Moreover, H. orientalis adults were constantly collected during the study period and the abundance of adults increased after Day 50. These results suggested that drift and reproduction were the main recolonization mechanisms that contributed to the rapid recovery of benthic caddisfly after the flood.ArticleZoosymposia. 5(1):235-243 (2011)journal articl

Horizontal distribution of benthic macroinvertebrates in Lake Kawaguchi, Japan

Article信州大学理学部附属諏訪臨湖実験所報告 9: 121-129(1995)departmental bulletin pape

Adult caddisfly (Trichoptera) attached to artificial lights in the middle reaches of the Shinano River from 2005 to 2007

The species composition and abundance of adult caddisflies attracted to the illuminated showcase of a vending machine set along the middle reaches of the Shinano River were investigated every Sunday night from April to November in 2005 to 2007. A total of 1,405 adult caddisflies was collected during the investigation periods. We identified a total of 13 species belonging to 11 genera of 8 families. The most abundant species was Psychomyia acutipennis (Ulmer 1908) each year. Psychomyia acutipennis adults were collected from mid-May to the beginning of October (the range of mean air temperature was 13.8 to 27.7°C), with its seasonal abundance divided into several peaks, i.e., the end of May, the beginning of June, and the end of August to the beginning of September in both 2006 and 2007. On the other hand, in 2005 when there was no large-scale summer flood and there were no marked abundance peaks. The present study suggests that the mean air temperature and summer floods impacted the seasonal abundance of P. acutipennis adults.ArticleZoosymposia. 5(1):143-146 (2011)journal articl

Bathymetric distribution of aquatic Oligochaeta in Lake Kizaki, Central Japan

Bathymetric distribution of aquatic oligochaetes was studied at 8 stations with different depths (mean depth 16.7 ± 9.4 m, min. 5.3 m, max. 29.4 m) in July 2012 in mesotrophic Lake Kizaki, Nagano Prefecture, Central Japan. The average density was 10424 ± 5346 individuals m-2. Oligochaetes were numerically dominant at all sampling stations. High density, sometimes more than 10000 individuals m-2,was recorded at 3 stations (St. 4, 5, and 6) deeper than 18 m. Maximum density was 20561 ± 13864 individuals m-2 at Station 4 (depth 29.4 m, ignition loss of sediment 13.5%, bottom water temperature 8.1 °C and DO of bottom water 0.12 mg l-1). We identified a total of 5 genera and 7 species belonging to three subfamilies: i.e., 1 species of Naidinae, 2 species of Rhyacodrilinae and 4 species of Tubificinae. Dominant species (in order of abundance) were Tubifex tubifex (Müller, 1774) (8550 ± 6317 individuals m-2; 82.0%) and Limnodrilus spp. (L. hoffmeisteri Claparède, 1862 and L. claparedeianus Ratzel, 1868) (1710 ± 1383 individuals m-2; 16.4%). Tubifex and Limnodrilus were obtained from every station, and the density of T. tubifex tended to be higher as the depth became greater, while Limnodrilus spp. was also widely distributed, but with a peak value at a depth of 5.3 m in the shallowest station. From the submerged plant zone, Ophidonais serpentina (Müller, 1773) was collected. An earlier study by Hirabayashi & Hayashi (1994) showed that in 1985 the average density of aquatic oligochaetes was 435 ± 428 individuals m-2, oligochaetes dominated in only four locations and were distributed over the whole lake approximately equally. Comparisons of our data with the earlier studies have shown that oligochaete density has increased greatly according to Hirabayashi & Hayashi (1994). We suggest that a decrease in dissolved oxygen concentration of bottom water was due to an increase in organic matter content of the sediment. As a result, T. tubifex could expand their habitats in the profundal zone.ArticleZoosymposia. 9:36-43 (2014)journal articl

Distribution of benthic insects in a riffle/pool section of the middle reaches of the Shinano River, Japan, with emphasis on Trichoptera

We investigated the density and taxonomic composition of benthic insects in a 300 m section of riffle / pool habitat in the Shinano River, Japan. The most abundant taxa were Chironomidae, followed by Trichoptera. The total density of caddisflies and their contribution to the total density of benthic insects ranged from 56 to 21,744 (mean 11,644) ind. m-2 and from 2.6 to 44.6 (mean 29.4) %, respectively. We conducted a canonical correspondence analysis using current velocity, depth, and the ash-free dry mass of epilithon as the main factors. Benthic insect assemblages were significantly associated with the longitudinal gradient of the riffle/ pool structure. Stenopsyche marmorata and hydropsychid species were abundant in the riffles whereas Psychomyia acutipennis were abundant in the pools.Article環動昆.22(1):17-22(2011)journal articl

Species composition and abundance of craneflies (Diptera: Tipulidae) in the highland lakes of Japan

We evaluated the relative abundance of tipulids in the Nishina Three Lakes and Lake Suwa, Japan, by capturing adult flies with light traps set around the shores of the lakes. Of the 149 individuals collected, 49 species were identified, and we described 19 newly recorded genera around these lakes. We collected seven species of adults at Lake Suwa, 27 species at Lake Aoki, 19 species at Lake Nakatsuna, and 16 species at Lake Kizaki. The most abundant species were Antocha bifida, Gonomyia (Leiponeura) incompleta, and Gonomyia sp. However, the most abundant species of each lake differed. Only A. bifida was collected from all the lakes. We calculated the Shannon-Wiener diversity index to compare the tipulid fauna among the lakes. The diversity index was the highest at 4.24 in Lake Aoki (an oligotrophic lake) and the lowest at 2.81 in Lake Suwa (a hypereutrophic lake). These results suggest that the diversity and relative abundance of adult tipulid species may be useful biological indicators for water quality assessment.ArticleJOURNAL OF FRESHWATER ECOLOGY. 26(1):91-97 (2011)journal articl

Silk protein of the larval caddisfly, Sienopsyche marmorata (trichoptera: stenopsychidae)(trichoptera: stenopsychidae)

Stenopsyche marmorata is one of the common caddisfly species inrivers and streamsin Japan which is distributed in East Palaearctic Region･ The larvae spin Silk fiber between stones on the bottom of Bowing water, the silk proteinofS･ marmorata would be one of the best sources of natural biopolymersthat could be used as materials for aquatic industrial purposes･ In order to analyze the basic characteristics towards further applications, we measured physical properties, thermal behaviorsand molecular confわrmation of the silk protein of larval S marmorata･ The wet weight of the larval body andthe silkgland of SOrata Were 543･5土5419and 44･7土17･9 mg, respectively, The water content of the liquid silk protein in the silkglands of the living larvae was 73.4土2.2%. The elongation atthe breaking point of the solid silk proteingland in dry state was 2･2%, whilethat of sampleinwet state was･ 6012%, suggestlngthe silk protein glands become soft and stretchable in wet conditions. FT-IR spectra of the silk protein film showed a major absorption band at 1650 cm-1 (Amide I band), which is attributed to the random coil molecular conformation. The silk fiber showed a major endothemiCpeak at 32loC onthe differential scanning calorimetry (DSC) curve, which position is slightly higher than the endothemic peak for the silk film, Suggesting an increaseinthe thermal stabilityfbr the silk fiber from caddisfly,Article信州大学山地水環境教育研究センター研究報告 6: 1-8(2010)departmental bulletin pape

A long-term eutrophication process observed from the changes in the horizontal distribution of profundal oligochaete fauna in mesotrophic-eutrophic Lake Kawaguchi, Japan

The purpose of this study was to record the oligochaete fauna in Lake Kawaguchi and clarify their horizontal distribution. In addition, annual changes in the lake were recorded. Samples were collected between 5 March 1993 and 7 March 2006 by using a standard Ekman-Birge sampler at 22 stations, and multipoint sampling surveys were carried out. As a result of the study, a total of 8 species belonging to 6 genera and 3 subfamilies were identified. The average density of oligochaetes for the entire lake was 5247 +/- 3873 ind m(-2) and the average wet weight of oligochaetes was 25.5 +/- 23.4 g m(-2) in 1993, compared to 1075 +/- 676 ind m(-2) and 2.7 +/- 1.7 g m(-2), respectively, in 2006. Tubifex tubifex had inhabited the entire lake bottom in 1993, but Limnodrilus spp. inhabited only the center of the lake in 2006. In recent years, the total number of oligochaetes has shown a tendency to increase, compared with the past record from the 1970s, suggesting that eutrophication is an ongoing process.ArticleTURKISH JOURNAL OF ZOOLOGY. 36(1):39-46 (2012)journal articl

Bathymetric distribution of benthic macroinvertebrates in deep Lake Motosu, Fuji Five Lakes, Japan

The distribution of benthic macroinvertebrates was studied in deep Lake Motosu (oligotrophic lake), Japan. Bathymetrical sampling surveys were carried out using a standard Ekman grab at each of 16 stations in the lake on 8 March 2013. The average densities of the benthic community for all the stations were 2185 ind./m2, comprised principally of Tubifex tubifex (Muller) 23.4%, Asellus hilgendorfi Bovallius 4.9% and chironomids 65.8%. T. tubifex and chironomids inhabited the entire lake bottom, with higher densities in the shallower region (25 m>) than in the deeper region (ca. 120 m). On the other hand, the density of A. hilgendorfi increased with water depth and was highest in the deeper regions (>70 m). The densities of chironomid larvae were lower in the deeper region, with fewer chironomid larvae located in the center of the lake (637 ind./m2). The most abundant species, Micropsectra yunoprima Sasa, exhibited the widest distribution from 10.0 m to 121.0 m (mean density 926 ind./m2), followed by Procladius choreusi (Meigen) from 10 m to 74.1 m (mean density 365 ind./m2). The results of this study were compared to previous data by Kitagawa (1973) on chironomid larvae. The densities of these chironomid larvae increased throughout the whole lake in 2013. The water quality has not undergone a major change since the 1970’s. In this study, the number of M. yunoprima larvae has shown a tendency to increase, especially in shallower regions; where they are widely distributed, suggesting the continuation of favorable bottom condition for larvae since the 1970’s.ArticleEuropian Journal of Environmental Science. 5(1):35-40 (2015)journal articl

Prediction of emergence period of overwintering Chironomid larvae (Diptera: Chironomidae) at lower reaches of the Kiso River, Central Japan.

Species composition and period of emergence were investigated for overwintering Chironomidae at the lower reaches of the Kiso River by rearing larvae to obtain fundamental information for drafting a plan to prevent outbreaks of nuisance midges. Adults of 9 species emerged from the substrate samples in February 2006. The four most abundant species, Stictochironomus akizukii, Hydrobaenus kondoi, Tanytarsus takahashii and Einfeldia dissidens, occupied 88.0% of the total abundance. Using effective accumulative temperature for emergence and in situ water temperatures, the in situ emergence periods of the overwintering generation in 2006 were predicted as until early March for H. kondoi, from the end of March to early May for S. akizukii and T. takahashii, and late April to mid-June for E. dissidens.Article衛生動物.58(3):183-190(2007)journal articl