Cowpea （Vigna unguiculata L. Walp.） and tomato （Lycopersicum esculentum L. Karst） are attacked by a wide range of insect pests worldwide. In many cases, pesticides are used to control the pests. In 2010 and 2011, ...Cowpea （Vigna unguiculata L. Walp.） and tomato （Lycopersicum esculentum L. Karst） are attacked by a wide range of insect pests worldwide. In many cases, pesticides are used to control the pests. In 2010 and 2011, we conducted field experiments to evaluate and compare the effectiveness of a biorational （Agroneem~） and conventional pesticide （imidacloprid or thiamethoxam） on insect pests of these crops. In the first year, two varieties of cowpea （Mississippi Silver and Pinkeye Purple Hull） and two of tomato （Mariana and German Johnson） were used; in the second year, the better performing of each group （Mississippi Silver and Mariana） were used for the study. A split-plot design with four replications in Year 1, and a randomized complete block design with six treatment combinations in Year 2. In the first year, both pesticide groups were applied following manufacturer＇s recommendation （10-14 d cycles）; and in the second year, the application of the pesticides was driven by economic thresholds level （ETL） of insect pests. The most prevalent species of insects recorded in both crops were in the families： Chrysomelidae, Pentatomidae, Cicadellidae, Vespidae, Sarcophagidae, Thripidae and Sphingidae. In both years, the diversity of insects on cowpea was greater than on tomato and more insects were observed in the second year compared to the first, despite the absence of significant difference （P 〉 0.05） between varieties in the treated plots. The yield of cowpea and tomato was comparable in all sprayed plots.展开更多
Mercury （Hg） is an environmental pollutant, and can bioaccumulate and biomagnify in the food web. Twenty four fish samples of different tropic level i.e., Herbivore, Omnivore and Carnivore were collected from two co...Mercury （Hg） is an environmental pollutant, and can bioaccumulate and biomagnify in the food web. Twenty four fish samples of different tropic level i.e., Herbivore, Omnivore and Carnivore were collected from two contaminated rivers, the Megna and the Buriganga which surround the Dhaka division for the assessment of toxic Hg. Fourteen samples were found to contain Hg in the range of 0.01-0.09 mg/kg. The highest Hg （0.09 mg/kg） was found in the Carnivore, Bele （Glossogobius giuris）. However, all fish species had lower amount of Hg than the maximum Hg limit （0.5 mg/kg for fish） set by World Health Organization （WHO）. Among all the fish species, the order of bioaccumulation was carnivore 〉 omnivore 〉 herbivore. Kajoli （Ailia coila）, Shing （Heteropnuestes fossilis）, Rui （Labeo rohita）, Chewa （Tryauchen vagine）, Rita （Rita rita）, Hilsha （Tenualosa ilisha）, Small Puti （Puntius sophore）, Bacha （Eutropiichthys vacha） and Chingri （smallprawn） were not found to contain any Hg which indicated that fish species from these rivers are safe for human consumption.展开更多
In temperate agroecosystems, avian responses in abundance and distribution to landscape attributes may be exacerbated by the coupling of natural seasons and farming practices. We assessed the sea- sonal roles of field...In temperate agroecosystems, avian responses in abundance and distribution to landscape attributes may be exacerbated by the coupling of natural seasons and farming practices. We assessed the sea- sonal roles of field type, field use in the surroundings, and distance from a field to the nearest woodlot on the abundance of seed-eating birds in a 225,000 km2 study area in the Pampas of central Argentina. During spring-summer and autumn of 2011-2013, we randomly selected 392 fields and used transect samples to collect data on abundance and presence of seed-eating bird species. We recorded a total of 11,579 individuals belonging to 15 seed-eating bird species. We used generalized lineal mixed models to relate bird abundance to field type, field use in the surroundings, and distance to the nearest woodlot. In spring-summer （breeding season） most bird responses were associated with their nesting requirements. Species that build their nests in trees, such as eared doves Zenaida auriculata, picazuro pigeons Patagioenas picazuro, and monk parakeets Myiopsitta monachus, were more abundant in fields closer to woodlots, whereas grassland yellow-finches Sicalis luteola, which nest at areas with tall grasses, were more abundant in fields with livestock use patches in the field surroundings. In au- tumn （non-breeding season）, most bird responses were associated with foraging and refuge needs. The high abundance of eared doves in crop stubbles and the association of pigeons at field surroundings dominated by croplands or at crop stubbles surrounded by livestock use fields revealed the intimate association of these species to sites with high availability of food resources. In addition, both picazuro pigeons and spot-winged pigeons Patagioenas maculosa were associated with woodlots, which provide suitable roosting sites. Our results show that in temperate agroecosystems, the relationships between field characteristics and seed-eating bird abundances vary with season.展开更多
Large-scale distribution and diversity patterns of mammalian herbivores, especially less charismatic species in alpine environments remain little understood. We studied distributional congruence of mammalian herbivore...Large-scale distribution and diversity patterns of mammalian herbivores, especially less charismatic species in alpine environments remain little understood. We studied distributional congruence of mammalian herbivores in the Trans-Himalayan region of Ladakh to see if the distributions of less prominent and smaller herbivores can be determined from those of larger and more prominent herbivores like ungulates. Using a similarity index, we assessed shared distributions of species in 20x20 km2 grid-cells in an area of about 80,000 km2. We used the Unweighted Pair-Group Method with Arithmetic Average （UPGMA） to classify mammalian herbivores into groups with similar distributions. We then used the G-test of independence to look for statistical significance of the groups obtained. We identified six groups of mammalian herbivores with distributions more similar than ex- pected at random. The largest group was composed of nine species whereas the other large group comprised six species. Canonical Correspondence Analysis （CCA）, used to relate the groups with environmental features, showed that the largest group occurred in higher and flatter areas, while the other large group occurred in lower and steeper areas. Large herbivores like ungulates can be used as surrogate for less prominent small herbivores while identifying areas for latter＇s protection in the inaccessible mountainous re- gions of the Trans-Himalaya [Current Zoology 59 （1）： 116-124, 2013].展开更多
文摘Cowpea （Vigna unguiculata L. Walp.） and tomato （Lycopersicum esculentum L. Karst） are attacked by a wide range of insect pests worldwide. In many cases, pesticides are used to control the pests. In 2010 and 2011, we conducted field experiments to evaluate and compare the effectiveness of a biorational （Agroneem~） and conventional pesticide （imidacloprid or thiamethoxam） on insect pests of these crops. In the first year, two varieties of cowpea （Mississippi Silver and Pinkeye Purple Hull） and two of tomato （Mariana and German Johnson） were used; in the second year, the better performing of each group （Mississippi Silver and Mariana） were used for the study. A split-plot design with four replications in Year 1, and a randomized complete block design with six treatment combinations in Year 2. In the first year, both pesticide groups were applied following manufacturer＇s recommendation （10-14 d cycles）; and in the second year, the application of the pesticides was driven by economic thresholds level （ETL） of insect pests. The most prevalent species of insects recorded in both crops were in the families： Chrysomelidae, Pentatomidae, Cicadellidae, Vespidae, Sarcophagidae, Thripidae and Sphingidae. In both years, the diversity of insects on cowpea was greater than on tomato and more insects were observed in the second year compared to the first, despite the absence of significant difference （P 〉 0.05） between varieties in the treated plots. The yield of cowpea and tomato was comparable in all sprayed plots.
文摘Mercury （Hg） is an environmental pollutant, and can bioaccumulate and biomagnify in the food web. Twenty four fish samples of different tropic level i.e., Herbivore, Omnivore and Carnivore were collected from two contaminated rivers, the Megna and the Buriganga which surround the Dhaka division for the assessment of toxic Hg. Fourteen samples were found to contain Hg in the range of 0.01-0.09 mg/kg. The highest Hg （0.09 mg/kg） was found in the Carnivore, Bele （Glossogobius giuris）. However, all fish species had lower amount of Hg than the maximum Hg limit （0.5 mg/kg for fish） set by World Health Organization （WHO）. Among all the fish species, the order of bioaccumulation was carnivore 〉 omnivore 〉 herbivore. Kajoli （Ailia coila）, Shing （Heteropnuestes fossilis）, Rui （Labeo rohita）, Chewa （Tryauchen vagine）, Rita （Rita rita）, Hilsha （Tenualosa ilisha）, Small Puti （Puntius sophore）, Bacha （Eutropiichthys vacha） and Chingri （smallprawn） were not found to contain any Hg which indicated that fish species from these rivers are safe for human consumption.
文摘In temperate agroecosystems, avian responses in abundance and distribution to landscape attributes may be exacerbated by the coupling of natural seasons and farming practices. We assessed the sea- sonal roles of field type, field use in the surroundings, and distance from a field to the nearest woodlot on the abundance of seed-eating birds in a 225,000 km2 study area in the Pampas of central Argentina. During spring-summer and autumn of 2011-2013, we randomly selected 392 fields and used transect samples to collect data on abundance and presence of seed-eating bird species. We recorded a total of 11,579 individuals belonging to 15 seed-eating bird species. We used generalized lineal mixed models to relate bird abundance to field type, field use in the surroundings, and distance to the nearest woodlot. In spring-summer （breeding season） most bird responses were associated with their nesting requirements. Species that build their nests in trees, such as eared doves Zenaida auriculata, picazuro pigeons Patagioenas picazuro, and monk parakeets Myiopsitta monachus, were more abundant in fields closer to woodlots, whereas grassland yellow-finches Sicalis luteola, which nest at areas with tall grasses, were more abundant in fields with livestock use patches in the field surroundings. In au- tumn （non-breeding season）, most bird responses were associated with foraging and refuge needs. The high abundance of eared doves in crop stubbles and the association of pigeons at field surroundings dominated by croplands or at crop stubbles surrounded by livestock use fields revealed the intimate association of these species to sites with high availability of food resources. In addition, both picazuro pigeons and spot-winged pigeons Patagioenas maculosa were associated with woodlots, which provide suitable roosting sites. Our results show that in temperate agroecosystems, the relationships between field characteristics and seed-eating bird abundances vary with season.
文摘Large-scale distribution and diversity patterns of mammalian herbivores, especially less charismatic species in alpine environments remain little understood. We studied distributional congruence of mammalian herbivores in the Trans-Himalayan region of Ladakh to see if the distributions of less prominent and smaller herbivores can be determined from those of larger and more prominent herbivores like ungulates. Using a similarity index, we assessed shared distributions of species in 20x20 km2 grid-cells in an area of about 80,000 km2. We used the Unweighted Pair-Group Method with Arithmetic Average （UPGMA） to classify mammalian herbivores into groups with similar distributions. We then used the G-test of independence to look for statistical significance of the groups obtained. We identified six groups of mammalian herbivores with distributions more similar than ex- pected at random. The largest group was composed of nine species whereas the other large group comprised six species. Canonical Correspondence Analysis （CCA）, used to relate the groups with environmental features, showed that the largest group occurred in higher and flatter areas, while the other large group occurred in lower and steeper areas. Large herbivores like ungulates can be used as surrogate for less prominent small herbivores while identifying areas for latter＇s protection in the inaccessible mountainous re- gions of the Trans-Himalaya [Current Zoology 59 （1）： 116-124, 2013].
