Papers by Dr Raj Kumar Thakur
Indian Journal of Entomology, 2018
Coriander is used as a strip crop to attract pollinators in order to facilitate pollination of ma... more Coriander is used as a strip crop to attract pollinators in order to facilitate pollination of major crops. This strip crop planting is important in determining the occurrence and abundance of pollinators in a locality. Amongst various insect pollinators, bees accomplish more than 80% of insect pollination. The wild bees including bumble bees, leaf cutting bees, alkali bees and carpenter bees are especially adapted for gathering pollen and nectar from flowers. In the present study insect pollinators were collected by fluorescent pan traps, scan sampling and sweep net during March, 2013–2014. An effort was made to study and develop keys for identification of Apis and non Apis bees. All the samples were identified on the basis of tongue length as long tongue and short tongue bees. The bees collected on coriander bloom represent the family Megachilidae, Halictidae and Apidae were found on coriander bloom. Most of the bees belong to genus Halictus having 3 different species (Family Halictidae), one species of family Megachilidae and two species of family Apidae.
Pest Management and Economic Zoology, 2010
Pest Management and Economic Zoology, 2010
Pest Management and Economic Zoology, 2010
Julius-Kühn-Archiv, 2018
Pollinators provide essential services in agriculture and ecosystem as a whole. The reproduction ... more Pollinators provide essential services in agriculture and ecosystem as a whole. The reproduction of nearly 85 % of the world’s flowering plants and production of 35 % of the world’s food crop depends on pollinators. In the recent years, the concern over the decline in pollinator population has gained impetus due to the decrease of plant species and vice versa. Although, the abundance of pollinators in the environment is influenced by a number of biotic and abiotic factors, the injudicious use of chemical pesticides is maximizing the damage. Neonicotinoid insecticides have successfully controlled pests in various crops. They have zero phytotoxicity and are compatible with all relevant crops. However, they may not only affect pest insect but also non-target organisms such as pollinators. In India, neonicotinoid pesticides were first registered for use in mid 1990s. With the overall decline in pollinators and worldwide neonicotinoid use, their impact on pollinators has become a cause o...
International Journal of Current Microbiology and Applied Sciences, 2017
The diversity of insect visitors on mustard (Brassica juncea L.) was studied at Dr. Y. S. Parmar ... more The diversity of insect visitors on mustard (Brassica juncea L.) was studied at Dr. Y. S. Parmar University of Horticulture and Forestry Nauni, Solan. A total of 88 insects belonging to 63 genera under 31 families and 9 orders were found to visit the mustard bloom. Order Hymenoptera formed higher percentage of the insect visitors in scan sampling. Apis cerana and A. mellifera abundance were higher by scan sampling methods. Relative abundance (by scan sampling) and diversity (by sweep net method), in general, was statistically more at full bloom than at onset and end of bloom. Other dipterans were the dominant insect trapped in mustard crop by fluorescent pan trap. All the three methods namely fluorescent pan traps, scan sampling and sweep net method are essential for determining pollinator diversity as no single method is fully reliable. Highest seed set, seed siliqua -1 and 1000 seed weight was obtained by open pollination followed by hand pollination. The minimum seed set, seed siliqua -1 and 1000 seed weight was observed in case of pollinators exclusion. Diversity, Pollinators insects, Honeybees, Brassica juncea, Seed set.
The importance of honeybees for the welfare of mankind is fast increasing not only as a source of... more The importance of honeybees for the welfare of mankind is fast increasing not only as a source of honey and wax, but also as chief pollinating agent. For this, concerted efforts are being made to improve the honeybee stock for increased honey yield, pollination proficiency, disease resistance and geographical adaptability.
Pollination is an important service of the regulation, promotion and cultural environment (Chagno... more Pollination is an important service of the regulation, promotion and cultural environment (Chagnon et al., 2015). It involves an integrated interaction framework that connects the vegetation of the earth, wildlife and human welfare (Kevan and Menzel, 2012). For the setting of fruits and seeds, many crops and wild plants need pollination. Pollination is the active and passive transfer within or between flowers of pollen (biologically speaking: transporting pollen from the output of anther to receiving the stigma of anthers). Pollination offers an important ecosystem service that contributes to biodiversity conservation and ensures the survival of species of plant, including crops. One can thank a bee, butterfly, bat, bird or other pollinator for one out of every three bites eaten. Any loss of biodiversity is a matter of public concern, but the loss of pollinating insects can be particularly disturbing due to the potential impact on plant reproduction and, therefore, on food security....
emergent Life Sciences Research
The present study was on pollinator diversity and foraging behavior of Apis mellifera Linnaeus an... more The present study was on pollinator diversity and foraging behavior of Apis mellifera Linnaeus and Apis cerana Fabricius on Chinese cabbage (Brassica rapa Linnaeus subspecies chinensis) grown under different farming systems. A total of 19 insects belonging to 16 genera under 7 families and 3 orders were recorded on Chinese cabbage. Among all insect visitors, A. mellifera (8.85 / 100 flowers) was the most dominant visitor. Significantly higher abundance was recorded in SPNF system followed by the control and CF system, respectively. The insect pollinators showed a positive correlation with temperature and a negative correlation with humidity. The average number of flowers visited by both foragers in one minute was significantly more in SPNF system followed by the control and CF system. The average time spent per flower by both foragers was significantly more in the CF system followed by the control and SPNF system. The number of loose pollen grains sticking to the body of insect poll...
Uncapping and removing of infested brood are assumed to be important traits within varroa resista... more Uncapping and removing of infested brood are assumed to be important traits within varroa resistance. Traditionally, selection in honey bee breeding programs is carried out on the basis of colony performance with respect to group traits such as honey production and colony defense. Hygienic behavior of colonies with respect to artificially killed, ill or parasitized brood has a moderate genetic basis but is also strongly affected by external influences. In addition colony level selection may not be very efficient for Varroa resistance breeding because of significant intracolonial variations, assumed to be caused by the multiple mating of the queen and consequently the composition of several patrilines within colonies. Recently we started selecting workers bees showing an extraordinary uncapping behavior of varroa-infested brood cells during 12 d infrared video observation (unpublished results). These workers, normally infertile, were induced to lay eggs. Unfertilized eggs develop in ...
Journal of Entomological Research, 2016
American Bee Journal, Feb 1, 1997
Nectar sugar production in flowers of Rubus ellipticus averaged 6.93 mg/flower at 24 h and the ac... more Nectar sugar production in flowers of Rubus ellipticus averaged 6.93 mg/flower at 24 h and the accumulation of the sugar in the bagged flowers occurred only during the first 24 h of flower opening. The amount remained unchanged up to 72 h and then the flowers began to wither. Nectarivores collected about 80 per cent of the total nectar secreted. The concentration of solutes as determined from the honey sac contents of foraging Apis mellifera, ranged from 65.3 to 71.3 %. Honey bees (A. mellifera and A. cerana indica) were the prominent nectar foragers on the bloom. Other Hymenoptera, various Diptera and Lepidoptera were the other visitors.
Uploads
Papers by Dr Raj Kumar Thakur