Contents lists available at ScienceDirect Ecotoxicology and Environmental Safety journal homepage: www.elsevier.com/locate/ecoenv Squamocin induce histological and ultrastructural changes in the midgut cells of Anticarsia gemmatalis (Lepidoptera: Noctuidae) Muhammad Fiaz a , Luis Carlos Martínez a , Marilza da Silva Costa a , Jamile Fernanda Silva Cossolin b , Angelica Plata-Rueda a , Wagner Gonzaga Gonçalves b , Antônio Euzébio Goulart Sant’Ana c , José Cola Zanuncio a , José Eduardo Serrão b, ⁎ a Department of Entomology, Federal University of Viçosa, 36570-000 Viçosa, MG, Brazil b Department of General Biology, Federal University of Viçosa, 36570-000 Viçosa, MG, Brazil c Institute of Chemistry and Biotechnology, Federal University of Alagoas, Avenida Lourival Melo Mota, Tabuleiro do Martins, 57072-900, Alagoas, Brazil ARTICLE INFO Keywords: Acetogenin Autophagy Bioinsecticide Respirometer rate Ultrastructure Velvet bean caterpillar ABSTRACT Annonaceous acetogenins (Annona squamosa Linnaeus) comprises of a series of natural products which are ex- tracted from Annonaceae species, squamocin proved to be highly efficient among those agents. Squamocin is mostly referred as a lethal agent for midgut cells of different insects, with toxic effects when tested against larva of some insects. In present study, LC 50 and LC 90 of squamocin for A. gemmatalis Hübner (Lepidoptera: Noctuidae) were calculated using probit analysis. Morphological changes in midgut cells were analyzed under light, fluorescence and transmission electron microscopes when larvae were treated with LC 50 and LC 90 of squamocin for 24, 48 and 72 h. Results revealed that the maximum damage to midgut cells was found under LC 90 where it showed digestive cells with enlarged basal labyrinth, highly vacuolated cytoplasm, damaged apical surface, cell protrusions to the gut lumen, autophagy and cell death. The midgut goblet cells showed a strong disorganization of their microvilli. Likewise, in insects treated with squamocin, mitochondria were not marked with Mitotracker fluorescent probe, suggesting some molecular damage in these organelles, which was reinforced by decrease in the respiration rate in these insects. These results demonstrate that squamocin has potential to induce enough morphological changes in midgut through epithelial cell damage in A. gemmatalis. 1. Introduction The velvet bean caterpillar, Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) is the main defoliating pest of soybean (Glycine max L. Merrill, Fabaceae) in Brazil (Sosa-Gomes, 2004; Panizzi, 2013). This species occurs from central region of the United States to Argentina and some Indian is- lands (Riffel et al., 2012). Anticarsia gemmatalis damages other crops also, such as peanuts, alfalfa, bean, pea, rice and wheat (Rahman et al., 2007). In Brazil, A. gemmatalis occurs throughout the year, especially in the vegetative stage of the plants and it is controlled by using synthetic insecticides (Navickiene et al., 2007; Panizzi, 2013). These insecticides may cause side effects such as pest resistance, environmental pollution, toxic waste, emergence of new pests and reduction of beneficial insects (Bourguet et al., 2000; Nicholson, 2007). Hence, alternative methods to control A. gemmatalis (De Nardo et al., 2001; Navickiene et al., 2007) need to be developed. The integrated pest and ecological management aim to use safer products than synthetic chemicals for the safety of human health and environment (Matsumura, 2004; Pavela, 2007). The search of natural substances for plant protection, especially in organic agriculture, has increased the interest in botanical insecticides (Martínez et al., 2015; Zanuncio et al., 2016). Annonaceous acetogenins comprised from a series of natural pro- ducts extracted from Annonaceae species, among which squamocin proved to be the promising agent. Squamocin also called anonin I, is an acetogenin with 37 carbon atoms, α,β-unsaturated γ-lactone ring and adjacent bis-tetrahydrofuran (bis-THF) ring (Rupprecht et al., 1990). Use of single molecules are important for synthesis of new inseticdes, and computational approaches in designing new insecticide can be really helpful (Speck-Planche et al., 2011), by providing better under- standing of physicochemical properties (Aschi et al., 2007), insecticidal activity (Liu et al., 2009; Khajehali et al., 2010; Sparks et al., 2001; Xue et al., 2007), and toxicological profiles (Eldred and Jurs, 1999). https://doi.org/10.1016/j.ecoenv.2018.02.080 Received 7 November 2017; Received in revised form 8 February 2018; Accepted 28 February 2018 ⁎ Correspondence to: Departamento de Biologia Geral, Universidade Federal de Viçosa, Avenida Peter Henry Rolfs, Campus Universitário Viçosa, Minas Gerais CEP: 36570-000, Brasil. E-mail addresses: fiaz.jahania@gmail.com (M. Fiaz), lc.martinez@outlook.com (L.C. Martínez), marilzacosta@gmail.com (M.d.S. Costa), jamilefscossolin@gmail.com (J.F.S. Cossolin), angelicaplata@yahoo.com.mx (A. Plata-Rueda), wagner2gufv@gmail.com (W.G. Gonçalves), aegs@qui.ufal.br (A.E.G. Sant’Ana), zanuncio@ufv.br (J.C. Zanuncio), jeserrao@ufv.br (J.E. Serrão). Ecotoxicology and Environmental Safety 156 (2018) 1–8 0147-6513/ © 2018 Elsevier Inc. All rights reserved. T