A Comparison of Aquatic Invertebrate Diversity between Paddy Fields under Traditional and Modern Management in Western Japan

We compared aquatic invertebrate diversity in paddy fields under traditional and modern management practices. We also examined the general factors that may be related to diversity within each paddy field. The Kitadan area was farmed with traditional management practices, with much longer periods of irrigations compared with the Kahoku area, which was farmed with modern agricultural practices using intermittent irrigation. We measured physicochemical factors and collected aquatic invertebrates from the two areas. Collected animal specimens were taxonomically identified and classified based by desiccation tolerance ability. At Kitadan, the total biodiversity parameters increased over time, while, biodiversity fluctuated temporally at Kahoku. The mean Shannon-Wiener diversity index was higher at Kitadan than at Kahoku. However, the mean taxon richness was not significantly different between locations. Both paddy fields were dominated by highly desiccation-tolerant invertebrates at the beginning of the rice cultivation period. Over time, the ratio of desiccation-sensitive invertebrates increased more at Kitadan than at Kahoku. Our canonical correspondence analysis showed that the time since rice transplanting, water permanence, pH, water depth, and chlorophyll a were significant factors affecting faunal assemblage composition. Our results indicate that water management practices have important roles in the aquatic biodiversity of paddy-field ecosystems

Notes on the lesser dung flies emerged from fungi in Japan (Diptera, Sphaeroceridae).

金沢大学理工研究域　自然システム学系キノコ類より発生した日本産フンコバエ科(改称)7種を記録した。日本においてフンコバエ類がキノコより発生した例は従来知られておらず, 今回が初めての記録である。フンコバエ類と発生したキノコ種は以下のとおりである。アシマダラオオフンコバエ, 新称Crumomyia annulus (Walker), キララタケ;ヤマトオオフンコバエ, 改称(マダラオオハヤトビバエ)C. nipponica (Richards), アミガサタケ;アシジロツヤホソフンコバエ, 新称Minilimosina (Svarciella) furculisterna (Deeming), キララタケ;モリフンコバエ, 新称Paralimosina japonica Hayashi, アミガサタケ;ヒメフンコバエ, 改称(ヒメハヤトビバエ)Spelobia luteilabris (Rondani), キララタケ・ヒトヨタケ・オオイチョウタケ・シカタケ;ホソカドマルフンコバエ, 改称(ホソカドマルハヤトビバエ)Terrilimosina longipexa Marshall, キララタケ;コガタカドマルフンコバエ, 改称(コガタカドマルハヤトビバエ)T. nana Hayashi, キララタケ。なお本科の科名には従来ハヤトビバエ科という和名が使われてきたが, 飛翔力が非常に弱い本科には実体に合わないので, 英名Lesser dung flyにちなみ, フンコバエ科という和名を新たに提唱した。 Seven species of the lesser dung flies emerged from fungi are recorded. Japanese records of fungi as food for sphaerocerid larvae are presented here for the first time. Two species, Minilimosina (Svarciella) furculisterna (Deeming, 1969) and Terrilimosina longipexa Marshall, 1987 are newly recorded from Hokkaido

Multiple blood feeding and host-seeking behavior in aedes aegypti and aedes albopictus (diptera: Culicidae)

The body size of mosquitoes can influence a number of bionomic factors, such as their blood-feeding ability, host attack rate, and fecundity. All of these traits are important determinants of their potential to transmit diseases. Among abiotic and biotic factors, high temperature and low nutrition in the developing stages of mosquitoes generally result in small adults. We studied the relationship between body size and multiple feeding in a gonotrophic cycle and some fecundity attributes by using three strains of two competent vector species, Aedes aegypti (L.) and Aedes albopictus (Skuse). We raised small and large mosquitoes under low and high food conditions in the laboratory to measure parameters of fecundity and blood-feeding behavior. Fecundity was positively correlated with body size in both species, whereas the number of bloodmeals, the frequency of host-seeking behavior, and egg retention were negatively correlated with body size in the Ae. albopictus Nagasaki strain. We found that multiple feeding and host-seeking behavior were negatively correlated with body size, i.e., small mosquitoes tended to have more contact with hosts. We found that two mechanisms that inhibit engorged mosquitoes from seeking out hosts, distension-induced and oocyte-induced inhibition, were not strong enough to limit host-seeking behavior, and multiple feeding increased fecundity. Size-dependent multiple feeding and host-seeking behavior affect contact frequency with hosts and should be considered when predicting how changes in mosquito body size affect disease transmission. © 2013 Entomological Society of America

Impact of climate change on the distribution of Aedes albopictus (Diptera: Culicidae) in Northern Japan: Retrospective analyses

The impact of climate change on the distribution of Aedes albopictus (Skuse) was analyzed in northern Japan, where chronological distribution records are incomplete. We analyzed local climate data using linear regression of the thermal suitability index (TSI) for the mosquito and mean annual temperature as functions of time. In northern Japan, thermal conditions since the early 20th century have become increasingly suitable for Ae. albopictus, more as a result of decreasing coldness in the overwintering season than increasing warmth in the reproductive season. Based on recent discovery records of Ae. albopictus in the northern border range, we determined thermal criteria for estimating when its persistent establishment became thermally possible. Retrospective analyses indicated that those criteria were reached in most coastal lowlands of northern Honshu before the accelerated temperature increase after the mid-1980s and the first records of this species after 1990; at some sites, temperature criteria were reached during or before the early 20th century. Expansion of the thermally suitable range after 1990 was supported only for inland areas and the northernmost Pacific coast. The estimated expansion rate was ≈26 km per decade. Our analyses also demonstrated the importance of local climate heterogeneity (apart from north-south or altitudinal temperature gradients) in determining the expansion pattern. © 2014 Entomological Society of America

Fungal defense against mycophagy in milk caps

Some Basidiomycetes exude latex, but very little is known about the nature of fungal latex. In this study, we examined the nature of latex in Lactarius Pers. 1797 spp. to clarify the role on fungivorous predation. In the field, we compared the degree of predation on taxonomically closely related latex-exuding Lactarius spp. and latex-non-exuding Russula Pers. 1796 spp. (Russulaceae) at developmental stages of sporocarps. We clarified that Russula spp. suffered more infestation than did Lactarius spp. at young and mature developmental stages, whereas Lactarius spp. did only at decaying stages. We measured the amount of latex exuded varied according to developmental stage and sporocarps parts in Lactarius spp.: mature sporocarps exuded more latex than did younger ones, while decaying sporocarps exuded the least, and the same patterns were observed at sporocarps parts: the amount of latex was more intense at hymenophore and cap than at stripe. At feeding experiments, three-band garden slugs Ambigolimax valentianus F´erussac, 1822 avoided feeding on sporophores of Lactarius spp. when they exuded latex, but fed on them when they did not. Our observations suggest that fungivores generally escape higher density of the latex at feeding using signs volatized by sporophores with exuding latex

Effects of temperature and diet on development and interspecies competition in Aedes aegypti and Aedes albopictus

We asked whether climate change might affect the geographic distributions of Aedes aegypti (L.) and Aedes albopictus (Skuse) (Diptera: Culicidae). We tested the effects of temperature, diet and the presence of congeneric species on the performance of immature stages of these two aedine species in the laboratory. Mosquitoes in three different species-density combinations were reared at four constant temperatures (20 °C, 25 °C, 30 °C, 35 °C) on low- or high-level diets. Of the four temperatures tested, mortality increased only at 35 °C in both species. Mortality was higher on the high-level diet than on the low-level diet at 35 °C, but not at other temperatures. The presence of congeneric species had a significant positive effect on mortality in Ae. albopictus, but not in Ae. aegypti. Both species developed more quickly at higher temperatures within the range of 20-30 °C; development was not enhanced at 35 °C. Population growth of Ae. albopictus was more stable, regardless of diet and temperature; that of Ae. aegypti varied more according to these two factors. These species-specific attributes may help to explain the latitudinal distribution of the mosquitoes and degree of species dominance where they are sympatric. © 2011 The Authors. Medical and Veterinary Entomology © 2011 The Royal Entomological Society

Spore dissemination by mycophagous adult drosophilids

Although most fungal spores are transported by wind, some remain on lamellae even after fungal fruiting bodies start to decay. This raises the question: are these remaining spores useless or instead transported by other means? In this study, we accordingly investigated whether adult dipteran insects transport fungal spores. Our examination revealed that fungal spores were present in intestines of most drosophilid adults but almost completely absent from those of other dipteran adults. At least some spores excreted by Drosophila angularis and D. brachynephros retained the capacity to germinate. Structural damage to spores that passed through the digestive tract of these two drosophilid species varied among fungal species, with a greater number of colorless spores generally damaged than colored ones. These results suggest that adult drosophilid flies, but not other dipterans, can transport fungal spores. © 2017, The Ecological Society of Japan.Embargo Period 12 month

Blood-feeding behavior of anopheles gambiae and anopheles melas in Ghana, Western Africa

金沢大学理工研究域自然システム学系Anopheles gambiae is the predominant malaria vector species in Ghana, western Africa, with a strong local presence of Anopheles melas Theobald along the southern coast. We studied the biting behavior of these two species of the Anopheles gambiae complex inland and at the coast in Ghana, with special attention to the local peoples\u27 preference for outdoor sleeping. We collected mosquitoes at two sites in 2007, representing the moist semideciduous forest zone and the strand and mangrove zone, and the sampling was repeated in the dry and rainy seasons. Sampled mosquitoes were examined for species, parity and size (wing length), and we identified the hosts of their bloodmeals. We interviewed 288 of the village people to determine where and when they slept outdoors. Our study confirmed that An. gambiae is the only species of the An. gambiae complex in the Ashanti region and revealed that An. melas is highly dominant on the western coast of Ghana. Both species showed high human blood rates in indoor resting mosquito samples. More people sleep outside on the coast than inland. An. melas demonstrated high exophily. An. gambiae bit people more frequently indoors and did so more often during the dry season than in the rainy season. We suggest that the degree of exophily in An. melas may be affected by humidity and the availability of human as well as by the mosquitoes\u27 innate habits. © 2010 Entomological Society of America

Preliminary field experiments on exophagy of Aedes albopictus (Diptera: Culicidae) in peridomestic habitat.

金沢大学理工研究域　自然システム学系Preliminary field experiments were conducted to examine the exophagy of Aedes albopictus in peridomestic habitat by using three different types of experimental buildings in Nagasaki, Japan and Chiangmai, Thailand. The density of females collected by suction traps enhanced by CO2 was high inside net-walled buildings and at outdoor sites with vegetation. On the other hand, the densities inside a normal walled building and at outdoor sites without vegetation, the microclimate conditions of both of which were different from the outdoor sites with vegetation, were low. To evaluate the effect of blocking by walls for Ae. albopictus invading to feed, an additional experiment by using a bamboo hut with openings of different sizes in the walls was conducted in Thailand. As the opening in the walls was smaller, the difference in the number of females between inside and outside of the hut became significantly larger. Therefore, the effect of physical blocking by walls was suggested. We proposed the presence of vegetation, the difference in environmental conditions inside buildings from those in vegetation due to blocking, and physical blocking by walls for invasion as ecological factors influencing the exophagy of Ae. albopictus. (author abst.

Tempo-spatial variation in feeding activity and density of Aedes albopictus (Diptera: Culicidae) at peridomestic habitat in Nagasaki, Japan.

金沢大学理工研究域　自然システム学系1998年9月, 長崎大学熱帯医学研究所敷地内で家屋周辺の茂み及び裸地においてヒトスジシマカの24時間採集を行い, 周辺環境の異なる採集場所における吸血活動性と密度のちがいを調べた。ヒトスジシマカの密度は茂みで高く, 屋内や裸地で低かった。吸血活動は薄明薄暮に高まり, 夜も高かった。最も活動性が高い薄暮には, 統計的な有意差はみられないが, 昼間や夜間に比べて屋内や裸地で採集される雌個体の割合が高かった。以上の結果からヒトスジシマカの生態における夜間の吸血活動の重要性と薄明薄暮には茂み以外に裸地や屋内などでも吸血される機会が増加することが示唆された。 To clarify the tempo-spatial variation in feeding of Aedes albopictus, a field investigation was conducted in a field where the species heavily infested, in Nagasaki. Feeding activity was observed in the nighttime as well as at dawn and dusk. The density was high at sites with vegetation and low at sites without vegetation and indoors. At sites with vegetation, the proportion of females decreased at dawn and dusk, while it increased at sites without vegetation and indoors. Feeding activity in nighttime is possibly common in Ae. albopictus, and the place of feeding expands from sites with vegetation to sites without vegetation and indoors at dawn and dusk