Currently, pesticides are considered ubiquitous pollutants in the environment. Exposure to these compounds has been associated with alterations in genetic material and the development of various types of cancer [
1,
2,
3]. Keto-enol insecticides are a new group of agrochemicals derived from tetronic and tetramic acids, marketed by Bayer since 2000 in countries such as: Mexico, USA, Brazil, Turkey, among others, for the control of a wide spectrum of phytophagous mites, aphids, psyllids, mealybugs, whiteflies, and other pests of sucking insects of agricultural crops [
4,
5]. These contain three active ingredients: Spirodiclofen (Envidor® 240SC), Spiromesifen (Oberon® 240SC) and Spirotetramat (Movento® 240SC) [
4,
6], and present a novel mechanism of action by interfering with lipid biosynthesis, acting as acetyl-coenzyme A carboxylase (ACCase) inhibitors [
7,
8]. Although keto-enol acaricides have selective toxicity against phytophagous mites, exposure to them has been associated with various toxic effects on non-target organisms. Spirodiclofen (Envidor® 240SC) is classified as a possible carcinogenic agent by the International Agency for Research on Cancer (IARC, 2009); it induces uterine adenocarcinoma, Leydig cell hypertrophy, vacuolization, degeneration and hyperplasia of interstitial cells in mammalian testes [
9,
10]; it produces alterations during the embryonic development of zebrafish (
Danio rerio) [
11], oxidative stress, lipid peroxidation and DNA damage in
Allium cepa meristems [
12]. Spirotetramat, (Movento® 240SC) has been shown to reduce the hatching rate of the eggs and induce loss of coordination in swimming African catfish (
Clarias gariepins) larvae [
13]; it significantly increases oxidative stress, lipid peroxidation and changes in the mobility of amphibian
Bufo bufo gargarinzas larvae [
14]; it generates oxidative stress, lipid peroxidation and DNA damage in earthworm coelomocytes (
Eisenia fetida) [
15]; in ovaries, it reduces weight, affects oogenesis and the expression of the Fox01 and Vnn1 genes in granulosa cells of female BALB/c mice [
16]; it inhibits the growth and reproduction rate of
Daphnia magna [
17]; it decreases the oviposition rate of the crustacean
Cyclops abyssorum [
18]. This insecticide also causes biochemical, histopathological, and physiological changes in the ovaries of adult zebrafish (
Danio rerio) [
19]. In zebrafish (
Danio rerio) embryos, it exerts teratogenic effects [
11], as an endocrine disruptor [
20], it affects lipid metabolism and causes mitochondrial lesions [
21]. We recently reported that the Movento® 240SC (Spirotetramat) and Envidor® 240SC (Spirodiclofen) insecticides induce DNA damage in
Drosophila melanogaster ovarian cells [
22]. However, the molecular mechanisms of response to DNA damage induced by keto-enol insecticides have not been characterized. DNA is continually subject to damage from exposure to environmental chemical compounds such as: pesticides [
22,
23], heavy metals [
24], or physical factors such as ionizing or ultraviolet radiation (IR or UV) [
25,
26], among others. The induction of DNA damage is considered one of the main risk factors for the development of genetic diseases, reproductive dysfunction, birth defects and carcinogenesis [
27,
28]. When DNA damage occurs, cells activate DNA damage response (DDR) mechanisms, which detect the site of the damage, amplifying a cascade of protein kinases and activation of downstream effectors that promote cell cycle arrest and DNA damage repair leading to apoptosis [
29,
30]. In the presence of DNA damage, an early event to DDR is phosphorylation of histone H2AX at carboxyl-terminal residue serine 139, known in mammals as γH2AX and in
D. melanogaster as γH2AV [
31,
32,
33]. The γH2AX variant is a very robust marker to detect double-strand breaks (DSBs), but also single-strand breaks (SSBs), DNA adducts, transcription blockade, and DNA replication [
34,
35]. γH2AX-producing lesions can be specifically immunodetected as discrete “foci” (sites) in interphase nuclei or mitotic chromosomes by specific fluorophore-labeled antibodies that recognize the phosphorylated residue of γH2AX, which is highly sensitive, allowing detection of γH2AX even when there are few DNA lesions [
36]. These foci can be quantified by means of fluorescence microscopy directly as the number of positive cells or as number of foci per nucleus or indirectly through their size and intensity of fluorescence emitted [
37,
38,
39]. This marker is dependent on the action of members of a family of kinases related to phosphatidylinositol 3-kinase (PI3K) which includes ATM (ataxia-telangiectasia mutated or Drosophila telomere fusion (Tefu)) and ATR in mammals (related to ATM and Rad3 or meiotic-41 in Drosophila (Mei-41)) [
40,
41]. Activated ATM/Tefu and ATR/Mei-41 phosphorylate several substrates, including Chk1/Grapes (Grp) and Chk2/loki (lok) kinases, which regulate cell cycle arrest, DNA repair, and apoptosis [
42,
43,
44]. The ATR/Chk1 pathway is activated mainly in the presence of stalled replication forks and DNA single-strand breaks (SSBs), controlling cell cycle arrest and DNA repair in S and G2/M phases [
41,
45]. The ATM/Chk2 pathway is activated upon induction of DNA double-strand breaks (DSBs), regulating cell cycle arrest in the G1/S phase and the activity of the p53 tumor suppressor that promotes the expression of target genes associated with DNA repair and apoptosis [
46,
47]. In Drosophila, a single ortholog of p53 has been identified, compared to the three mammalian members (p53, p63 and p73), which has facilitated its study [
48,
49]. Drosophila is an excellent organism recommended by the European Center for the Validation of Alternative Methods (ECVAM) for research in toxicology [
50] and used for the study of various human carcinogenic processes [
51,
52] including DNA damage response mechanisms in
in vivo systems [
53,
54,
55].The Drosophila ovary has functioned as a system to characterize DNA damage response and repair mechanisms [
56], specifically the germarium, the residence site of germinal stem cells (GSCs), the oocyte division, differentiation, and formation site [
57], in which double-strand breaks (DSBs) are generated in a programmed manner during the meiotic recombination process [
58]. A considerable number of gene-deficient mutants involved in DNA damage and repair response have been generated in Drosophila [
59,
60,
61,
62] and are used in the evaluation of the genotoxic and mutagenic potential of various chemical compounds, such as pesticides [
63,
64]. However, there are no studies on the response mechanisms to DNA damage induced by exposure to these agrochemicals, especially in the ovary germarium. Therefore, the present study is the first to report on the mechanisms of response to DNA damage (DDR) induced by exposure to the keto-enol insecticides Movento® 240SC and Envidor® 240SC using mutant strains of
D. melanogaster (ATM
tefu, ATR
mei-29D, Chk1
grp/Chk2
lok, Chk1
grp, p53
dp53) and wild type (Oregon R) through γH2AV expression by confocal immunofluorescence microscopy.