Toxicological and Histopathological Effects of Boric Acid on <I>Atta sexdens rubropilosa</I> (Hymenoptera: Formicidae) Workers

Abstract

The current study compared the toxicity of different concentrations of boric acid in adult workers of Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae), with toxicological bioassays, and examining the dose-dependent and time-dependent histopathological changes, of the midgut, Malpighian tubules, and postpharyngeal glands. Our results revealed the importance of conducting toxicological bioassays combined with morphological analyses of the organs of ants chronically exposed to insecticides used in commercial ant baits. In vitro bioassays showed that boric acid significantly decreases the survivorship of workers regardless of concentration, whereas the morphological data suggested progressive dose-dependent and time-dependent changes in the organs examined, which were evident in the midgut. The midgut is the first organ to be affected, followed by the postpharyngeal gland and Malpighian tubules. This sequence is in agreement with the absorption pathway of this chemical compound in the midgut, its transference to the hemolymph, possibly reaching the postpharyngeal glands, and excretion by the Malpighian tubules. These progressive changes might be due to the cumulative and delayed effect of boric acid. Our findings provide important information for the understanding of the action of boric acid in ant baits in direct and indirect target organs.

Effect of boric acid on antioxidant enzyme activity, lipid peroxidation, and ultrastructure of midgut and fat body of Galleria mellonella

“…Perhaps increased midgut size was due to vacuolization of cells. Similar ultrastructural changes were observed by Sumida et al (2010) in ants and da Silva et al (2010) in bees exposed to BA. Midgut cells were vacuolized, membranes were ruptured, and myelinated figures were observed, too.…”

Histological description of immature Chironomus columbiensis (Diptera: Chironomidae): A potential contribution to environmental monitoring

“…The strongly basophilic nature of the microvilli of region III cells of the midgut (a characteristic not reported by Richardi et al () in C sancticaroli ) could be associated to the high presence of acid‐rich (DNA and RNA) organelles, such as the rough endoplasmic reticulum, the Golgi apparatus and free ribosomes, which indicate a secretory function of mitochondria in order to provide energy for active transport and the intake of substances (Jarial & Engstrom, ). Several studies in insects have shown that the midgut is a target organ for contamination, due to the absorption of xenobiotic substances acquired orally (El‐Saad, Kheirallah, & El‐Samad, ; Gutiérrez, Santos, Serrão, & Oliveira, ; Sumida et al, ). Nevertheless, there are few studies that have applied histopathological markers in the midgut of Chironomidae larvae (Lavarías et al, ; Rey, Long, Pautou, & Meyran, ; Rey, Pautou, & Meyran, ; Richardi et al, ).…”

Loci Contributing to Boric Acid Toxicity in Two Reference Populations ofDrosophila melanogaster

“…Boric acid has been shown to be effective against various ant species (Klotz and Moss 1996; Klotz et al 1996), and the larvae of both honeybees (da Silva Cruz et al 2010) and wax moths (Hyrsl et al 2007; Buyukguzel et al 2013). Boric acid administration has morphological effects on the midgut and malpighian tubules in leaf-cutting ants (Sumida et al 2010), leads to abnormalities in midgut cells in Argentine ants (Klotz et al 2002) and honeybee larvae (da Silva Cruz et al 2010), and promotes irregularities in both midgut tissue and the fat body in wax moths (Buyukguzel et al 2013). Nonetheless, the physiological mechanisms responsible for the mortality associated with boric acid intake are not clear.…”