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Ingestion and diet destination in Culiseta inornata : responses to water, sucrose and cellobiose
Author(s) -
FRIEND W. G.,
SMITH J. J. B.,
SCHMIDT J. M.,
TANNER R. J.
Publication year - 1989
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/j.1365-3032.1989.tb00945.x
Subject(s) - cellobiose , sucrose , midgut , biology , ingestion , sugar , crop , hindgut , food science , taste , botany , carbohydrate , horticulture , agronomy , larva , biochemistry , cellulose , cellulase
. At ambient temperature, contact with free liquids containing sugar induces Culiseta inornata Williston (Diptera: Culicidae) females to adopt the nectar‐feeding mode of behaviour. While in this mode, two distinct control mechanisms appear to operate: one controlling the amount of ingestion, the other diet destination. Mosquitoes were exposed to water and various concentrations of sucrose and cellobiose in water. Only small or taste amounts of water were imbibed, and it was directed to the midgut. Cellobiose solutions of less than 0.1M were treated as water. Cellobiose was phagostimulatory; as the concentration increased from 0.1 to 0.5 M the percentage of insects ingesting large amounts rose from 11% to 68%. Cellobiose diets were directed primarily to the midgut. Sucrose was also phagostimulatory. As the concentration increased from 0.025 to 0.2 M, the percentage of insects ingesting large amounts increased from 20 to 92. At lower sucrose levels, insects ingesting large amounts put it mainly into the crop, while insects ingesting smaller amounts put the diet into the midgut or both the crop and midgut. At sucrose concentrations of 0.4 M or more, most insects took large amounts and directed it to the crop. Different combinations of sucrose and cellobiose with a total concentration of 0.5 M all caused insects to take mainly large meals. At sucrose concentrations of 0.2M and above, the insects responded as they would to sucrose alone, directing the diet to the crop. At sucrose concentrations of 0.1M or less, diet destination patterns were more complex, with individual animals depositing the diet in the crop, the midgut, or in both. A behavioural model is presented which postulates different receptors for sucrose and cellobiose, control of diet destination via differential control of midgut and crop valves, and variation of threshold values according to endogenous factors.