ISSN:
1570-7458
Keywords:
Bruche monovoltine
;
hivernation
;
alimentation artificielle
;
alimentation naturelle
;
osidases digestives
;
univoltine bruchid
;
hibernation
;
artificial diet
;
natural diet
;
digestive glycosidases
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Description / Table of Contents:
Summary Bruchus affinis Fröl. is an univoltine bruchid that develops in the South-West of France on a few Leguminosae (Fabaceae) plants of the Lathyrus group. At the beginning of the summer, females lay their eggs on young green pods. Larval development takes place in the growing seeds and the adults emerge in autumn. They hibernate, probably under the barks of trees and/or in dead leaves, like other univoltine bruchids. Hibernating adults become temporarily active when the temperature increases, and we suppose that they may feed on microorganisms present in the litter. In June, large numbers of these beetles can be seen on young flowers of the Lathyrus group. Pollen of L. sylvestris and L. latifolius could induce ovogenesis in the female. In two groups of adults, we have studied (1) glycosidase activity in digestive tracts of insects (IA2) maintained at 4–5° C on artificial diet (water + honey), and (2) carbohydrase enzymes which could allow hibernating adults (IE5) to feed on microorganisms when hibernating in external conditions. The glycosidase activity in the alimentary tract of B. affinis fed on artificial diet is not much varied. α-glycosidase has the most important activity, after which come α-mannosidase, β-galactosidase and β-mannosidase activities. Very high activity was measured on saccharose, starch and maltose. The activity was intermediate on laminarin and raffinose. Low activity was found on pectin, lichenin, glucomannane, carboxy-methyl-cellulose and cellobiose. The decrease of most of the glycosidase activities during hibernation is due partly to decrease of temperate, partly to scarcity of food. Amylase and maltase activities could allow hibernating adults to use glycogen contained in yeast and fungi. β-1,3-glucans, which can be hydroiyzed by laminarinase, are components of cellular walls of fungi and yeasts, and form reserves in Protozoans. Lactase (β-galactosidase) and mannosidase activities could hydrolyze several carbohydrates present in glycoproteins known as components of the cell wall.
Notes:
Abtract Bruchus affinis Fröl. (Coleoptera: Bruchidae), espèce monovoltine, passe une grande partie de sa vie imaginale en état d'hivernation dans des abris naturels. Les adultes hivernants, sexuellement immatures, peuvent redevenir momentanément actifs à l'occasion de réchauffements temporaires au cours de l'hiver; il est probable qu'ils se nourrissent alors de microorganismes. Les caractéristiques générales de l'équipement osidasique digestif de B. affinis ont été déterminées à partir d'adultes maintenus en conditions artificielles. L'α-glucosidase s'est révélée être l'osidase la plus active de l'équipement enzymatique qui, par ordre d'activité décroissante, comporte également une α-mannosidase, une β-galactosidase, une β-mannosidase, une α-galactosidase et une β-glucosidase La comparaison des activités osidasiques des adultes en hivernation à l'extérieur avec celles d'invertébrés de la litière montre que B. affinis pourrait, durant l'hivernation, consommer divers microorganismes (levures, champignons, bactéries,...). B. affinis possèderait en fait un équipement osidasique digestif assez étroitement spécialisé qui, au cours du cycle biologique de l'insecte, pourrait évoluer en fonction des variations saisonnières du milieu trophique.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00376404
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