Regeneration of the midgut during larval stages of the red flour beetle Tribolium castaneum (Herbst, 1797) upon fasting

• Published in: Journal of stored products research 2022-09, Vol.98, p.102003, Article 102003
• Main Authors: Santos, Daniele das Graças dos, Reis e Silva, Rebeca, de Barros, Cintia Monteiro, Nepomuceno-Silva, José Luciano, Nunes-da-Fonseca, Rodrigo, da Silva, José Roberto
• Format: Article
• Language: English
• Subjects: Digestion; Food deprivation; Intestinal stem cells; Midgut; Tribolium castaneum
• ISSN: 0022-474X; 1879-1212
• DOI: 10.1016/j.jspr.2022.102003

The beetle Tribolium castaneum feeds on amylaceous grains, being considered a pest of stored products which causes severe losses to the agricultural productive chain worldwide. The success of this insect as a pest relies, besides other abilities, on the endurance capacity of its developmental stages to survive inhospitable environmental conditions, such as the transition between food reservoirs. Being unable to fly, T. castaneum larvae must remain viable upon starvation and the preservation of the intestinal tract is pivotal in this process. To investigate the remodeling of the midgut of T. castanum larvae, a model of fasting, followed by refeeding was established. The histological profiles of midguts from normally fed insects, from larvae starved for up to 120 h, as well as of refed individuals, were compared. Furthermore, the activity of cysteine and serine proteases and α-amylase was also analyzed under these conditions. During the fasting, the midgut epithelium progressively lost most of its spatial organization, which was recovered 72 h after refeeding. During the fasting, the activity of α-amylase decreased drastically, while serine and cysteine proteinases suffered more discrete reductions. Upon refeeding, α-amylase and serine protease activities increased gradually and reached prior levels in 72 h, while cysteine proteases showed only a small rise, not recovering to previous levels. Overall, from a histological and enzymatic perspective, the intestinal epithelium of larvae of T. castaneum undergoes an extensive remodeling to become almost completely reorganized after 72 h of refeeding. It is reasonable that the observed tissue reconstruction and digestion recovery relies heavily on the nidi of intestinal stem cells. The resilience of T. castaneum larvae upon fasting may explain, at least in part, the remarkable success of this species as a storage pest and should be considered in the design of larvae-based pest control strategies. •T. castaneum larvae have their midgut structure dismantled in five days of fasting.•Intestinal α-amylase activity decreases drastically until the 5th day of fasting.•Serine and cysteine proteases activities are only partially affected by fasting.•Allowing larvae to refeed restores midgut tissue structure in up to three days.•Allowing refeeding restores amylolytic and proteolytic activities in up to three days.