Studies on Characterization of Syrphid Flies Syrphidae Diptera And Their Role as Beneficial Insects

Abstract

Syrphid flies are commonly called as hover flies (Syrphidae; Diptera) and are commonly newlinespotted hovering over flowers during bright sunny days. They are known to be next best pollinators after newlinehoney bees. Present investigations on Syrphid flies were conducted in various locations of Kumaon region newlineand in vitro experiments were done at G. B. Pant University of Agriculture and Technology, Pantnagar newlineduring 2020-22, to know their diversity, and potential as pollinators and predators on mustard aphid. newlineBesides, their morphometric and molecular characterization was also done. A total of 737 syrphid flies newlinewere collected from various locations of Kumaon region including Pantnagar. A total of 28 species from newlinetwo subfamilies (Eristalinae and Syrphinae) and five tribes (Eristalini, Milesiini, Bachhini, Paragini, newlineSyrphini) were identified. In Pantnagar, Episyrphus viridaureus showed highest relative density in newlineHorticulture Research Centre (HRC). SDI and H exhibited that Vegetable Research Centre (VRC) had newlinemore species diversity and evenness while least diversity indices were recorded at HRC. Among other newlinelocations of Kumaon region, Joshigaon (Bageshwar) have revealed the highest relative density of newlineEpisyrphus balteatus (35.11%) whereas as lowest was in Dinapani (Almora) where only 10 species were newlinepresent when compared to other locations. Species diversity and evenness was highest in Sariyatal newline(Nainital; SDI=0.9332, H =2.805) while it was lowest in Dinapani (SDI=0.7906, H =1.728). newlineThe experiments on morphometry of eight species showed that Eristalis tenax was largest in all 17 body newlinecharacters measured with the mean body length and breadth, head length and width, antennal length, newlinebreadth, arista length thorax length and breadth, fore wing length and breadth, haltere length, Fore leg newlinelength, mid leg and hind length and abdomen was 12.370±0.111 and 5.252±0.072, 3.880±0.054 and newline4.941±0.057, 0.880±0.015, 0.424±0.008 and 1.517±0.027, 5.174±0.077 and 3.751±0.097, 11.590±0.119 newlineand 3.965±0.063, 1.249±0.014, 8.653±0.122, 9.906±0.119 and 13.046±0.139, 6.489±0.081 and newline5.375±0.092mm, respectively. While Sphaerophoria indiana and Melanostoma orientale were found newlinesmallest with some body character measurements overtaking one another. newlineA total of 20 Syrphid flies were subjected for Mitochondrial cytochrome I sequencing. The newlinephylogram separated them into two clusters (A and B) and further each of these clusters divided into 2 sub newlineclusters each (A1, A2 and B1, B2). Further sub clusters A1, A2, divided into 2 groups each and sub cluster newlineB2 divided into 3 groups. newlineThe trial on pollination efficiency of syrphid flies in comparison to giant honey bee, Apis dorsata newlineon mustard and litchi indicated that in mustard A. dorsata was more efficient pollinator followed by S. newlineindiana (Second best) with Pollination Efficiency Index of 74.23 Relative abundance and foraging speed newlinewas highest in E. tenax with (6.37 flies/m2/5 mins) and (7.97 flowers/min), respectively while lowest was newlinerecorded by A. dorsata (4.66 bees/m2/ 5 mins) (5.17 flowers/min). Time spent/flower was recorded highest newlineby A. dorsata (13.17 sec/flower) while lowest was by E. tenax (6.81 sec/flower). In litchi, also the A. newlinedrsata ranked number based on pollination efficiency index (PEI) followed by E. balteatus with PEI of newline116.2The relative abundance was highest by E. tenax with 8.68 flies/m2/5 mins, while lowest was recorded newlineby A. dorsata (4.53 bees/ m2/5 mins). Foraging rate was highest in case of A. dorsata (7.90 sec/flower) newlinewhile lowest by E. tenax (3.29 sec/flower). Foraging speed was highest for E. balteatus (8.15 flower/ min) newlinewhile it was lowest in A. dorsata (3.49 flowers/min). newlineAmong the three syrphid fly species evaluated for their predatory potential, E. balteatus (total newlineconsumption= 475aphids/larva) came out as a gregarious feeder on Mustard aphid Lipaphis erysimi newlinefollowed by E. confrator (408.75 aphids/larvae) and S. indiana (281.25 aphids/larvae), all showing highest newlineconsumption during third instar stage. newline