Main Article Content

The morphological, cytological and physiological aspects of the digestive tract of the siarid Bradysia impatiens fourth-instar larvae were studied using bright-field microscopy. The division of the digestive tract into the stomodeum (foregut), the mesenteron (midgut) and the proctodeum (hindgut) was observed; the second of which being composed of endocrine, regenerative, column-shaped cells. The larvae did not present a crop; hence digestion of the bolus occurs in the midgut. They have two well-developed gastric caeca, where it can be assumed that great nutrient absorption takes place. The peritrophic membrane is type II, with a pore size that allows the passage of molecules up to 150 kDa, and which divides the midgut into two regions: the endoperitrophic and ectoperitrophic spaces. There are four Malpighian tubules present. The midgut has a pH gradient ranging from mildly alkaline in the foregut to neutral in the caeca and hindgut. It has a recirculation mechanism stretching from the endoperitrophic to the ectoperitrophic space and vice versa, which improves digestion and optimizes enzyme production. The morphophysiological features observed in B. impatiens larvae confirm that these organisms are well-adapted detritivores. Additionally, the peritrophic membrane protects the midgut from pathogenic agents.

Marín-Cruz, V. H., Rodríguez-Navarro, S., Barranco-Florido, J. E., Terrón-Sierra, R. A., & Cibrián-Tovar, D. (2020). Morphophysiological aspects of the digestive tract in IV stage larvae of Bradysia impatiens (Diptera: Sciaridae). Revista Colombiana De Entomología, 45(2), e7962.

BOLOGNESI, R.; TERRA, W. R.; FERREIRA, C. 2008. Peritrophic membrane role in enhancing digestive efficiency theoretical and experimental models. Journal of Insect Physiology 54: 1413-1422.

BOONSRIWONG, W.; SUKONTASON, K.; OLSON, J. K.; VOGTSBERGER, R. C.; CHAITHONG, U.; KUNTALUE, B.; NGERN-KLUN, R.; UPAKUT, S.; SUKONTASON, K. L. 2006. Fine structure of the alimentary canal of the larval blow fly Chrysomya megacephala (Diptera: Calliphoridae). Parasitology Research 100 (3): 561-574.

CHAPMAN, R. F. 1998. The insects: structure and function, 4th ed. Cambridge University Press, Cambridge, Reino Unido.770 p.

CIBRIÁN, T. D.; GARCÍA, D. S.; DON JUAN, M. B. 2008. Manual de identificación y manejo de plagas y enfermedades en germoplasma y planta producida en viveros. Comisión Nacional Forestal. México. 153 p.

CRUZ, L. C. da; MORELLI S. M. R. L. 1985. Aspectos da ultra-estructura dos cecos gástricos da larva de Odontosciara sp. (Diptera: Sciaridae). Revista Brasileira de Zoologia 3 (4): 181-188.

DE VEAU, E. J. I.; SCHULTZ, J. C. 1992. Reassessment of interaction between gut detergents and tannins in Lepidoptera and significance for gypsy-moth larvae. Journal of Chemical Ecology 18 (8): 1437-1453.

DO VALE, F. V.; PEREIRA, H. M.; FIGUEIREDO, N. G. 2007. Midgut pH profile and protein digestion in the larvae of Lutzomyia longipalpis (Diptera: Psychodidae). Journal of Insect Physiology 53 (11): 1151-1159.

DOW, J .A. T. 1981. Countercurrent flows, water movements and nutrient absorption in the locust midgut. Journal of Insect Physiology 27 (9): 579-585.

DOW, J. A. T. 1986. Insect midgut function. pp. 187-328. En: Evans, P. D.; Wigglesworth, V. B. (Eds.). Advances in Insect Physiology. Volumen 19: University Cambrige, Academic Press. London. England. 434 p.

EVANGELISTA, L. G.; LEITE, A. C. 2007. Salivary glands of second and third instars of Dermatobia hominis (Diptera: Oestridae). Journal of Medical Entomology 44 (3): 398-404.

EDWARDS, M. J.; JACOBS-LORENA, M. 2000. Permeability and disruption of the peritrophic matrix and caecal membrane from Aedes aegypti and Anopheles gambiae mosquito larvae. Journal of Insect Physiology 46 (9): 1313-1320.

FERREIRA, C.; TERRA, W. R. 1982. Function of midgut ceca and ventriculus microvilli bound enzymes from cells of different midgut regions of starving and feeding Rhynchosciara americana larvae. Insect Biochemistry 12 (3): 257-262.

FERREIRA, C.; RIBEIRO, A. F.; TERRA, W. R. 1981. Fine structure of the larval midgut of the fly Rhynchosciara and its physiological implications. Journal Insect Physiology 27 (8): 559-570.

FERREIRA, C.; CAVASIN, G.; GARCIA, S. H. H.; GERIS, R.; GARCIA, S. I. 2010. Alterações morfo-histológicos em larvas de Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae) causadas pelo tanino catéquico isolado da plantado cerrado Magonia pubescens (Sapindaceae). Revista Patología Tropical 39 (4): 309-321.

GONTIJO, N. F.; ALMEIDA-SILVA, S.; COSTA, F. F.; MARES-GUIA, M. L.; WILLIAMS, P.; MELO, M. N. 1998. Lutzomyia longipalpis: pH in the gut, digestive glycosidases and some speculations upon Leishmania development. Experimental Parasitology 90 (3): 212-219.

HEGEDUS, D.; ERLANDSON, M.; GILLOT, C.; TOPRAK, U. 2009. New insights into peritrophic matrix synthesis, architecture, and function. Annual Review of Entomology 54: 285-302.

HURLEY, B. P.; SLIPPERS, B.; WINGFIELD, B. D.; GOVENDER, P.; SMITH J. E.; WINGFIELD, M. J. 2010. Genetic diversity of Bradysia difformis (Sciaridae: Diptera) populations reflects movement of an invasive insect between forestry nurseries. Biological Invasions 12 (4): 729-733.

INTAKHAN, N.; JARIYAPAN, N.; CHANMOL, W.; SOR-SUWAN, S.; PHATTANAWIBOON, B.; SAEUNG, A.; CHOOCHOTE, W.; BATES, P. A. 2014. Midgut ultrastructure of fourth instar Ochlerotatus togoi (DIPTERA: CULICIDAE). Southeast Asian Journal of Medicine and Public Health 45 (6): 1301-1315.

JAMES, L. N. 2002. Insect physiology and biochemistry. CRS Press. Washington D.C., EE. UU. 485 p.

KIM, S. K.; ADLER, P. H. 2009. Digestive system of larval black flies (Diptera: Simuliidae): structure and phylogeny. Invertebrate Biology 128 (2): 182-204.

LEE, W. Y.; CHEN, M. E.; LIN, T. L. 1998. Morphology and ultrastructure of the alimentary canal of Oriental fruit fly Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) (I): the structure of the foregut and cardia. Zoological Studies 37 (2): 95-101.

LEHANE, M. J. 1997. Peritrophic matrix structure and function. Annual Review of Entomology 42: 525-550.

MARÍN-CRUZ, V. H.; HUERTA, H.; RODRÍGUEZ-NAVARRO, S. 2017. Familia Sciaridae. pp. 444-446. En: Cibrian-Tovar, D. (Ed.). Fundamentos de entomología forestal. Universidad Autónoma Chapingo. Texcoco, Estado de México, México. 531 p.

MARÍN-CRUZ, V. H.; CIBRIÁN-TOVAR, D.; MÉNDEZ-MONTIEL, J. T.; PÉREZ-VERA, O. A.; CADENA-MENESES, J. A. 2015a. Control del mosco fungoso negro Lycoriella ingenua (Dufour, 1839) y Bradysia impatiems (Johannsen, 1912) (Diptera: Sciaridae) en Pinus montezumae Lamb. Revista Mexicana Ciencias Forestales 6 (27): 90-100.

MARÍN-CRUZ, V. H.; CIBRIÁN-TOVAR, D.; MÉNDEZ-MONTIEL, J. T.; PÉREZ-VERA, O. A.; CADENA-MENESES, J. A.; HUERTA, H.; RODRÍGUEZ-YAM, G.; CRUZ-RODRÍGUEZ, J. A. 2015b. Biología de Lycoriella ingenua y Bradysia impatiens (Diptera: Sciaridae). Madera y Bosques 21 (1): 113-128.

MARTIN, M. M.; MARTIN, J. S.; KUKOR, J. J.; MERRITT, R. W. 1980. The digestion of protein and carbohydrate by the stream detritivore, Tipula abdominalis (Diptera: Tipulidae). Oecologia 46 (3): 360-364.

MARTÍNEZ, M. I. 2002. Técnicas básicas de anatomía microscópica y de morfometría para estudiar a los insectos. Boletín de la Sociedad Entomológica Aragonesa 30: 187-195.

MENZEL, F.; SMITH, J. E.; CHANDLER, J. P. 2006. The sciarid fauna of the British Isles (Diptera: Sciriadae), including descriptions of six new species. Zoological Journal of the Linnean Society 146 (1): 1-147.

MILLER, N.; LEHANE, M. S. 1990. In vitro perfusión studies on the peritophic membrane of the Tsetse fly Glossina morsitans morsitans (Diptera: Glossinidae). Journal Insect Physiology 36 (11): 813-818.

MOHRIG, W.; MENZEL. F. 2009. Sciaridae (Black fungus gnats). pp. 279-292. En: Brown, B. V.; Borkent, A.; Cumming, J. M.; Wood, D. M.; Woodley N. E.; Zumbado, M. A. (Eds.). Manual of Central American Diptera Vol 1. Monograph Publishing Program. Canada: National Research Council of Canada. 714 p.

MOHRIG, W.; HELELR, K.; HIPPA, H.; VILKAMAA, P.; MENZEL, F. 2012. Revision of black fungus gnats (Diptera: Sciaridae) of North America. Studia Dipterologica 19 (1/2): 141-286.

NEIRA, O. M.; VANEKERIS, L.; CORENA-MCLEOD, M. D. P.; LINSER, P. J. 2008. A microarray-based analysis of transcriptional compartmentalization in the alimentary canal of Anopheles gambiae (Diptera: Culicidae) larvae. Insect Molecular Biology 17 (1): 61-72.

NUNES, A. S.; SERRÃO, J. E.; LANE, M. A. 2010. Alterations in the fat body and midgut of Culex quinquefasciatus larvae following exposure to different insecticides. Micron 41 (6): 592-597.

ROELFSTRA, L.; VLIMANT, M.; BETSCHART B.; PFISTER, K.; DIEHL, P. A. 2010. Light and electron microscopy studies of the midgut and salivary glands of second and third instars of the horse stomach bot, Gasterophilus intestinalis. Medical and Veterinary Entomology 24 (33): 236-249.

SHARMA, B. R.; MARTIN, M. M.; SHAFER, J. A. 1984. Alkaline proteases from the gut fluids of detritus feeding larvae of the crane fly Tipula abdominalis (Say) (Diptera: Tipulidae). Insect Biochemistry 14 (1): 37-44.

SHIN, S. G.; LEE, H. S.; LEE, S. 2012. Dark winged fungus gnats (Diptera: Sciaridae) collected from shiitake mushroom in Korea. Journal of Asia-Pacific Entomology 15 (1): 174-181.

STOFFOLANO, G. J.; HASELTON, A. 2013. The adult dipteran crop: a unique and overlooked organ. Annual Review of Entomology 58: 205-225.

TAHA, N.; ABDEL-MEGUID, A.; EL-EBIARIE, A.; TOHAMY, A. A. 2010. Ultrastructure of the midgut of the early third larval instar of Chrysomya megacephala (Diptera:Calliphoridae). Journal of American Science 6 (10): 1-6.

TERRA, W. R. 1990. Evolution of digestive systems of insects. Annual Review of Entomology 35: 181-200.

TERRA, W. R. 2001. The origin and funtions of the insect peritrophic membrane and peritrophic gel. Archives of Insect Biochemistry and Physiology 47: 47-61.

TERRA, W. R.; FERREIRA, C. 1983. Further evidence that enzimes involved in the final stages of digestion by Rhynchosciara americana do not enter the endoperitrophic space. Insect Biochemistry 13 (2): 143-150.

TERRA, W. R.; FERREIRA, C. 2005. Biochemistry of digestion. pp. 171-224. En: Gilbert, L. I.; Iatrou, K.; Gill, S. S. (Eds.). Comprehensive Molecular Insect Science. Elsevier, Oxford. 560 p.

TERRA, W. R.; FERREIRA, C. 2012. Molecular and evolutionary physiology of insect digestion. pp. 93-115. En: Panizzi, A. R.; Parra, R. P. (Eds.). Insect bioecology and nutrition for integrated pest management. Taylor & Francis Group, LLC. Estados Unidos de América. 732 p.

TERRA, W. R.; ESPINOZA-FUENTES, F. P., RIBEIRO, A. F.; FERREIRA, C. 1988. The larval midgut of the housefly (Musca domestica): ultrastructure, fluid fluxes and ion secretion in relation to the organization of digestion. Journal of Insect Physiology 34 (6): 463-472.

URÍA, E.; MORA, C. 1996. Apuntes para el curso teórico práctico de histología animal. ENCB. IPN. México. 277 p.