Coloration of stinging insects is often based on contrasted patterns of light and black pigmentations as a warning signal to predators. However, in many social wasp species, geographic variation drastically modifies this signal through melanic polymorphism potentially driven by different selective pressures. To date, surprisingly little is known about the geographic variation of coloration of social wasps in relation to aposematism and melanism and to genetic and developmental constraints. The main objectives of this study are to improve the description of the colour variation within a social wasp species and to determine which factors are driving this variation. Therefore, we explored the evolutionary history of a polymorphic hornet, Vespa velutina Lepeletier, 1836, using mitochondrial and microsatellite markers, and we analysed its melanic variation using a colour space based on a description of body parts coloration. We found two main lineages within the species and confirmed the previous synonymy of V. auraria Smith, 1852, under V. velutina, differing only by the coloration. We also found that the melanic variation of most body parts was positively correlated, with some segments forming potential colour modules. Finally, we showed that the variation of coloration between populations was not related to their molecular, geographic or climatic differences. Our observations suggest that the coloration patterns of hornets and their geographic variations are determined by genes with an influence of developmental constraints. Our results also highlight that Vespa velutina populations have experienced several convergent evolutions of the coloration, more likely influenced by constraints on aposematism and Müllerian mimicry than by abiotic pressures on melanism.

Adequate knowledge about bee flora is the prerequisite to initiate bee keeping. A study was conducted at Kabre area of Dolakha district during 1997-1999 to identify existing bee flora and develop a floral calendar. Based on the interview with bee farmers and visual observations, 119 important plant species were recorded, out of which 47 species were found major sources for honeybees. Spring season (mid-March to mid-June) and autumn season (mid-Sept to Oct) were identified as honey flow periods having a number of floral plants such as Guizotia abyssinica, Fraxinus floribunda, Prunus cerasoides, Pyrus communis, Castanopsis indica, Brassica spp., Citrus spp., Berberis spp., Rubus spp., Rhododendron spp. and Trifolium spp. Winter season (mid- Nov to Feb) is the critical dearth period with a few flowering plants like Reinwardtia indica, Pogestemon glaber, Caesalpinia spp. and Eupatorium spp. Depending upon the climatic conditions, possibility of planting multipurpose plants has been discussed. Based on available flora, major characteristics of these plant species, utility status and flowering duration a bee floral calendar was developed for Kabre. To conserve these floras, attention must be made to maintain and multiply the existing flora.Key words: Apis cerana; Bee flora; Bee keeping; Dearth period; Honey flowDOI: http://dx.doi.org/10.3126/narj.v4i0.4859Nepal Agriculture Research Journal Vol. 4&5, 2001/2002Page: 18-25Uploaded date: 8 June, 2011

Fluke infestation in domestic animals is one of the major problems of farmers in tropical condition of Chitwan. A prospective study was done in western Chitwan, Bharatpur Metropolitan City, ward 26 &16, Nepal in two different seasons-summer and winter to describe the seasonal prevalence of fluke infestation in dairy cattle and buffalo. Sedimentation technique of faecal examination was performed to recover the parasite eggs. In the study, the prevalence of fluke infestation was found to be higher in the summer (26%) than in winter (22%). Similarly, among cattle Jersey cross (39.5%) showed the highest infestation of flukes among the breeds followed by Jersey (12.5%), among the buffalo breed the rate of infestation was found higher in Murrah cross (21.4%) followed by local (20.0%). No Murrah breed in the study were positive for GI parasite. In the study carried out in 38 calf, 7 heifer and 55 mother the faecal examination for fluke egg was positive 26.3% of calves, 28.6% of heifers and 21.8% of mothers respectively. Out of 43 buffalo and 57 cattle the parasitic infestation was found in 18.6% and 28.1% of sample respectively. Although cattle were seen more susceptible to flukes, the relation was not statistically significant. The study shows that the fluke infestation may be producing subsequent production loss due to its high prevalence in dairy cattle and buffalo.

Predatory hornets are considered as one of the major constraints to beekeeping industry. Therefore, its incidence and predation rate was studied throughout the year at two locations- rural and forest areas of mid-hill in Laliptur district during 2016/017 to 2017/018. Observation was made on the number of hornet and honey bee captured by hornet in three different times of the day for three continuous minutes every fortnightly on five honeybee colonies. During the study period, major hornet species captured around the honeybee apiary at both locations were, Vespa velutina Lepeletier, Vespa basalis Smith, Vespa tropica (Linnaeus) and Vespa mandarina Smith. The hornet incidence varied significantly between the years and locations along with different observation dates. Their incidence and predation rates were low in early spring and summer that gradually increased with the highest peak in October and November in both locations. The maximum predation was on mid-November (62.07%) and early-November (53.49%) at rural and forest locations, respectively during 2016/017. In 2017/018, the highest predation was on early-November (70.27%) at rural area while it was in mid-November (58.62%) in the apiaries near the forest area. The population of hornet was considerably higher at forest areas and their incidence around the honeybee apiaries were negatively correlated with rainfall. Hence, assessment of the temporal and spatial population variations and predation rates along with weather parameters is helpful in to develop sustainable management plans of the hornet in apiary.

Buckwheat is one of the crops on which pollination services from honeybees and other insect pollinators are necessary for obtaining quality and higher grain yield. Increasing plant biodiversity is an important strategy to attract and restore pollinators in an agro-ecosystem. Among many ways to increase plant biodiversity, the present study aimed to identify whether the increasing intra-specific crop diversity enhances pollinator diversity in buckwheat (Fagopyrum esculentum Moench). The field experiment was conducted at research field of Hill Crop Research Program, Kabre, Dolakha district, Nepal at an altitude of 1750 m asl during 2016. Thirteen treatments, each representing either a single or combination of two or three buckwheat genotypes were laid out in randomized complete block design (RCBD) with two replications. Pollination diversity or richness as well as their foraging behavior in the buckwheat flowers and associated yield parameters were measured for each treatment. Plots with higher intra-specific varietal mixture were found to attract more pollinators and had higher yield than plots with two or single genotypes. Pollinator visitation was higher during morning hour of the day (9 am to 10 am), which was followed by mid-day (12 noon to 1 pm) and the least visitation was observed during late afternoon (3 pm to 4 pm). The benefit of increasing intra-specific crop diversity on pollination services is not optimized and practiced under current farming practices. Hence, multi-location and multi-season studies are recommended to strengthen the current findings for future endeavors.