Syrphid diversity and feeding and ovipositional response of aphidophagous species
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Date
2022
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Punjab Agricultural University, Ludhiana
Abstract
The present study entitled “Syrphid diversity and feeding and ovipositional response of aphidophagous species” was carried out at the Entomological Research Farm, G.S. Kalkat Laboratories, Punjab Agricultural University, Ludhiana. For the study of syrphid diversity, three different locations of Punjab viz. Ludhiana, Muktsar and Gurdaspur were visited at fortnightly interval for collection of syrphids. Total of fourteen syrphid species viz. Ischiodon scutellaris (Fabracius), Helophilus hybridus (Loew), Eristalinus anesus (Scopoli), Eristalis tenax (Linnaeus), Eristalinus arvorum (Fabricius), Stomorhina discolor (Feracius), Episyrphus balteatus (Dee Geer), Eupeodes corollae (Fabricius), Metasyrphus confrater (Weidemann), Eupeodes frequens (Matsmura), Melanostoma scalare (Fabricius), Sphaerophoria chongjini (Bonkowska) and Chrysotoxum baphyrum (Walker) belonging to two subfamilies (Syrphinae and Eristalinae) were reported. Among all these syrphid species E. balteatus was found to be most abundant in all the three locations. For the molecular identification, the mtCO1 gene was amplified using universal primers (HCO and LCO) and sequence of this gene from all fourteen syrphid species were subjected to blast analysis in NCBI data base for confirmation of syrphid species. On the basis of number of syrphid species and number individuals of each species Shannon Wiener diversity index was calculated. It was recorded that Gurdaspur population was found to show maximum diversity index (H=2.23 and 2.25) for both years i.e. 2020 and 2021. The laboratory experiments on functional response and numerical response of four predatory syrphid species viz. I. scutellaris, E. balteatus, E. frequens and M. confrater predating upon varying prey densities of Lipaphis erysimi and Brevicoryne brassicae revealed type II functional and numerical response. By all the four syrphid species an increase in the number of aphids consumed by single syrphid larva (first and second instar) and number of eggs laid by single female was found to be increased with respect to increasing initial prey density and after reaching to its upper asymptote it became stable or decreased monotonically. Under the experiment on effect of conspecific and other predators of oviposition response of four predatory syrphids species viz. I. scutellaris, E. balteatus, E. frequens and M. confrater in semi-field conditions, it was recorded that in the presence of coccinellid grubs, the number of eggs laid by one female of each syrphid species decreased remarkably and no egg laying found when there was no prey (aphid) was present on plant cut section.
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Paramveer Singh (2022). Syrphid diversity and feeding and ovipositional response of aphidophagous species (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.