Morphometry of the midgut of Melipona quadrifasciata anthidioides (Lepeletier) (Hymenoptera: Apidae) during metamorphosis

Abstract

In Hymenoptera, midgut changes begin in the last instar. At this stage, the larval epithelial digestive cells degenerate, leaving only the basal membrane and the regenerative cells which will develop into a new epithelium during the pupal stage and in the adult. Epithelium renewal is followed by changes in volume and shape of the midgut. Morphometric analysis of digestive cells and total midgut volume of Melipona quadrifasciata anthidioides (Lepeletier) were conducted to verify whether cell volume increase are sufficient to account for the total midgut volume increase that occurs during metamorphosis. An increase in midgut volume was verified in spite of the scarcity of cell proliferation found during metamorphosis. At the end of metamorphosis, the increase in cell volume was not sufficient to explain the increase in volume of the midgut, indicating that an increase in the number of digestive cells is apparently necessary. Nevertheless, the mechanism by which regenerative cells reconstitute the epithelium during metamorphosis remains unknown.

Epithelial remodelling of the midgut in the post-embryonic development of Partamona helleri (Apidae, Meliponini)

“…The proliferation of regenerative cells, in turn, as observed in the present study, had already been reported in the midgut of larvae, pre-pupae and pupae of M. quadrifasciata (Martins et al 2006;Cruz et al 2011Cruz et al , 2013. The analyses carried out confirmed that regenerative cells in bees initiate the differentiation process and the formation of digestive cells in the pre-pupal stage (Neves et al 2003a, b).…”

“…The midgut of insects is the main organ responsible for food digestion and the absorption of nutrients. In the midgut epithelium, including that of bees, there are three major cell types: endocrine cells, which produce and secrete peptides with endocrine functions; digestive cells, which perform the digestion and absorption of food; and regenerative cells or stem cells, responsible for cell renewal and remodelling of the epithelium (Serrão and Cruz-Landim 1996;Martins et al 2006;Malaspina and Silva-Zacarin 2006;Cruz et al 2007Cruz et al , 2011Nagy et al 2018).…”

“…The remodelling of the intestinal epithelium of bees begins in the last larval stage, mainly involving the processes of cell death, proliferation and cellular differentiation (Cruz-Landim and Mello 1970;Neves et al 2002;Illa-Bochaca and Montuenga 2006;review in Hakim et al 2010;Gonçalves et al 2017). In this process of remodelling, the differentiated cells of the larva degenerate and are replaced, in the pre-pupal stage, by regenerative cells that differentiate and reorganise to form the adult individual's epithelium (Neves et al 2003a, b;Martins et al 2006;Cruz et al 2011).…”

“…Research carried out with the purpose of understanding the remodelling of intestinal epithelium of stingless bees during metamorphosis used the species Melipona quadrifasciata as a model (Cruz-Landim and Mello 1970;Neves et al 2002Neves et al , 2003aCruz-Landim and Cavalcante 2003;Martins et al 2006;Fernandes et al 2010;Cruz et al 2011Cruz et al , 2013. The remodelling of the midgut epithelium of M. quadrifasciata involves the proliferation of regenerative cells and the expansion of these cells during cell differentiation.…”

The fine structure of the midgut epithelium in Xerobiotus pseudohufelandi (Iharos, 1966) (Tardigrada, Eutardigrada, Macrobiotidae)

“…Midgut progenitor cells that differentiate into all types of the midgut epithelial cells have been described mainly for arthropods. They are described as cells which show the features of both midgut stem cells and digestive cells (Martins et al, 2005;Cruz et al, 2011;Chajec et al, 2012). The amount of reserve material (e.g.…”