Datura metel-synthesized silver nanoparticles magnify predation of dragonfly nymphs against the malaria vector Anopheles stephensi.
Malaria is a life-threatening disease caused by parasites transmitted to people and animals through the bites of infected mosquitoes. The employ of synthetic insecticides to control Anopheles populations leads to high operational costs, non-target effects, and induced resistance. Recently, plant-borne compounds have been proposed for efficient and rapid extracellular synthesis of mosquitocidal nanoparticles. However, their impact against predators of mosquito larvae has been poorly studied. In this study, we synthesized silver nanoparticles (AgNPs) using the Datura metel leaf extract as reducing and stabilizing agent. The biosynthesis of AgNPs was confirmed analyzing the excitation of surface plasmon resonance using ultraviolet-visible (UV-vis) spectroscopy. Scanning electron microscopy (SEM) showed the clustered and irregular shapes of AgNPs, with a mean size of 40-60 nm. The presence of silver was determined by energy-dispersive X-ray (EDX) spectroscopy. Fourier transform infrared (FTIR) spectroscopy analysis investigated the identity of secondary metabolites, which may be acting as AgNP capping agents. In laboratory, LC50 of D. metel extract against Anopheles stephensi ranged from 34.693 ppm (I instar larvae) to 81.500 ppm (pupae). LC50 of AgNP ranged from 2.969 ppm (I instar larvae) to 6.755 ppm (pupae). Under standard laboratory conditions, the predation efficiency of Anax immaculifrons nymphs after 24 h was 75.5 % (II instar larvae) and 53.5 % (III instar larvae). In AgNP-contaminated environment, predation rates were boosted to 95.5 and 78 %, respectively. Our results documented that D. metel-synthesized AgNP might be employed at rather low doses to reduce larval populations of malaria vectors, without detrimental effects on behavioral traits of young instars of the dragonfly Anax immaculifrons.
Division of Entomology, Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore, 641046, Tamil Nadu, India.
Kadarkarai
K
Murugan
Division of Entomology, Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore, 641046, Tamil Nadu, India.
Devakumar
D
Dinesh
Division of Entomology, Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore, 641046, Tamil Nadu, India.
Prabhu Jenil
PJ
Kumar
Division of Entomology, Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore, 641046, Tamil Nadu, India.
Chellasamy
C
Panneerselvam
Division of Entomology, Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore, 641046, Tamil Nadu, India.
Jayapal
J
Subramaniam
Division of Entomology, Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore, 641046, Tamil Nadu, India.
Pari
P
Madhiyazhagan
Division of Entomology, Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore, 641046, Tamil Nadu, India.
Udaiyan
U
Suresh
Department of Environmental Biology, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
Marcello
M
Nicoletti
Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.
Abdullah A
AA
Alarfaj
Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.
Murugan A
MA
Munusamy
Department of Reproduction, National Research Institute for Child Health and Development, Tokyo, 157-8535, Japan.
Akon
A
Higuchi
Department of Parasitology, Heinrich Heine University, Düsseldorf, Germany.
Heinz
H
Mehlhorn
Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124, Pisa, Italy. benelli.giovanni@gmail.com.
Giovanni
G
Benelli
D000818:Animals; D000852:Anopheles / Q000187:drug effects* / Q000502:physiology; D058530:Datura metel / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D007303:Insect Vectors / Q000187:drug effects* / Q000502:physiology; D007306:Insecticides / Q000494:pharmacology; D007814:Larva / Q000187:drug effects / Q000502:physiology; D008288:Malaria / Q000635:transmission; D053758:Nanoparticles / Q000737:chemistry / Q000378:metabolism*; D009758:Nymph / Q000187:drug effects / Q000254:growth & development; D063191:Odonata / Q000502:physiology*; D010936:Plant Extracts / Q000737:chemistry* / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism; D011679:Pupa / Q000187:drug effects / Q000254:growth & development; D012834:Silver / Q000378:metabolism* / Q000494:pharmacology
D007306:Insecticides; D010936:Plant Extracts; D012834:Silver
Anax immaculifrons; Anopheles stephensi; Biological control; Biosafety; Green synthesis; Mosquito-borne diseases; Nanobiotechnologies; Non-target effects