Dietary silver nanoparticles reduce fitness in a beneficial, but not, pest insect species

Authors: AFRASIABI, ZAHRA - Soka University; Popham, Holly; Stanley, David; SURESH, DHANANJAY - University Of Missouri System; FINLEY, KRISTEN - Lincoln University Of Missouri; CAMPBELL, JONELLE - Lincoln University Of Missouri; KANNAN, RAGHURAMAN - University Of Missouri System; UPENDRAN, ANANDHI - University Of Missouri System

Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/15/2016
Publication Date: 8/10/2016
Citation: Afrasiabi, Z., Popham, H.J., Stanley, D.W., Suresh, D., Finley, K., Campbell, J., Kannan, R., Upendran, A. 2016. Dietary silver nanoparticles reduce fitness in a beneficial, but not, pest insect species. Archives of Insect Biochemistry and Physiology. doi:10.1002/arch.21351.

Interpretive Summary: Silver nanoparticles are used in many industrial applications and they have been considered as possible insecticides. Here we consider to broad issues associated with use of these nanoparticles as insecticides. First, reports of insect-lethal nanoparticles are based on simplistic methods of making the nanoparticles that yield nanoparticles of non-uniform shapes and sizes, leaving questions about the precise treatments test insects experienced. Second, we do not know how AgNPs influence beneficial insects. We assessed the influence of nanoparticles on life history parameters of two agricultural pest insect species, tobacco hornworm and cabbage looper and a beneficial predatory insect species, spined soldier bug, all of which act in cropping systems. Rearing the two pest species on standard media amended with nanoparticles led to negligible influence on the pest species, however, they led to retarded development, reductions in adult reproduction, and increased mortality in the beneficial predator. These negative effects on the beneficial species, if also true for other beneficial insect species, would have substantial negative implications for continued development of nanoparticles for insect pest management programs.

Technical Abstract: Silver nanoparticles (AgNPs) have antimicrobial and insecticidal properties and they have been considered for their potential use as insecticides. While they do, indeed, kill some insects, two broader issues have not been considered in a critical way. First, reports of insect-lethal AgNPs are often based on simplistic methods that yield nanoparticles of non-uniform shapes and sizes, leaving questions about the precise treatments test insects experienced. Second, we do not know how AgNPs influence beneficial insects. This work addresses these issues. We assessed the influence of AgNPs on life history parameters of two agricultural pest insect species, Heliothis virescens (tobacco hornworm) and Trichoplusia ni (cabbage looper) and a beneficial predatory insect species, Podisus maculiventris (spined soldier bug), all of which act in agroecosystems. Rearing the two pest species on standard media amended with AgNPs led to negligible influence on developmental times, pupal weights, and adult emergence, however, they led to retarded development, reductions in adult weight and fecundity, and increased mortality in the predator. These negative effects on the beneficial species, if also true for other beneficial insect species, would have substantial negative implications for continued development of AgNPs for insect pest management programs.