Browsing by Author "Dyola, Urmila"
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Item Survey on Simulium Species (Diptera: Simuliidae) and Abundance in Relation with Water Quality at Lalitpur District, Kathmandu(Central Department of Zoology, 2008) Dyola, UrmilaSix months study (Oct, 2007 –March, 2008) was carried on black-flies at three sites (Godawari River, Nakkhu River and Karmanasa River) of Lalitpur District here by designated as site I, site II and site III respectively. Out of a total of 952 samples collected, only 729 were identified on the basis of larval, pupal and adult morphological features into four different species of Simulium i.e S. (Simulium.) variegatum gr., S. (S.) multistriatum gr ., S (S.) tuberosum gr. and S (S.).indicum. Study on monthly variations was exposed to significant variation of black-fly species in every month in site I and II but no record of the fly in site III was made throughout the study period. Common type of species diversity in site I (H¯=1.154) and II (H¯= 1.50) was recorded due to alike environmental factors in those sites and January appeared to be the most suitable month for the abundance of species while October as the least. Present study also justified the accountable relationship of species with temperature; DO and water current in both site I and site II.Item Taxonomic diversity and community structure of insect pollinators in Shivapuri-Nagarjun National Park, Central Nepal(Institute of Science and Technology, Zoology, 2022) Dyola, UrmilaInsect pollinators are important agents mediating useful services for human and the ecosystem. Large number of wild plants and agricultural crops depend on the pollinators for their pollination. Global trend has shown decline of several taxa of pollinators and indicating habitat loss as major driving factor. Several studies have been done on pollinators in agricultural and natural areas however there are very few works describing their distribution and diversity in protected area despite the fact that these areas are globally important for preserving disturbance-intolerant pollinators. Wild flowering plants of the park may play an important role for conservation of pollinators. This study explored the taxonomic diversity and the community structure of insect pollinators; bees, butterflies, and hoverflies of Shivapuri-Nagarjun National Park (SNNP). Furthermore, five least collected wild bees during two years of survey were used as model pollinators to check the distribution. The research also documented plant-pollinators interaction to find out the key pollinators, plants that serve as hubs of pollinators, and seasonal variations of pollinators.The survey was done in SNNP for two consecutive years (2018–2019) in four different habitats; Open trail, Forest trail, Managed habitat, and Grassland using both belt transect and colored pan traps methods in three different elevations that ranges from 1,400m–2,700m. The results showed 42 and 34 species of bees and hoverflies respectively. Out of them, 11 species: Amegilla candida, A. fallax, A.insularis, A. quadrifasciata, Elaphropoda impatiens, Ceratina perforatrix, Colletes similis, Megachile conjuncta, Nomia iridescens, Xylocopa collaris, and X. violacea are new country records of bee and Graptomyza nigripes, Lycastris albipes, and Volucella trifasciata are new country records of hoverflies. Likewise, community structure of pollinators presented a total of 167 different species; the butterflies being the most dominant group (48.50%) followed by bees (29.94%) and hoverflies (21.56%). Diversity indices in alpha level was analysed; the Open trail was comparatively more diverse (4.85), followed by the Managed habitat (4.30). Whittaker Beta diversity analyzed the high species turnover between Forest trail and Managed habitat. Environmental variables like humidity, atmospheric temperature, and flower resources in different elevation have a significant effect (p<0.05) on pollinating insects. The species distribution model showed Nomada mutabilis, Thyreus decorus, T. himalayensis, Megachile femorata, and X. violacea are spread out across a broad region vii in the park. The accuracy of model predictions for all five bees are statistically well specified (AUC is greater than 0.07). The plant-pollinator interactions were complex and asymmetrical showing Eristalis tenax, E. cerealis, and Pieris canidia as key pollinators. Ageratina adenophora, Bidens pilosa, and Trifolium repens were observed as the most visited plants by pollinators. Seasonal comparisons showed that there is high species turnover of bees and hoverflies between spring and autumn seasons ( p<0.05). Based on these results, it is clear that the park provides suitable habitats for many species of pollinators. Open trials with a rich herb and shrub coverage can provide foraging habitat to pollinators. High diversity and abundance of insects in Open trial can aid good pollination service in this habitat. Other habitats like managed area, grassland, and forest can be important determinants of wild bees resulting different pollinator community. Frequent visits of pollinators in exotic plants compared to native plants could alter the native plant- pollinator interaction in long term if former plants are not managed.