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Post‐feeding bubbling behaviour in fluid‐feeding Diptera: concentration of crop contents by oral evaporation of excess water
Author(s) -
HENDRICHS J.,
COOLEY S. S.,
PROKOPY R. J.
Publication year - 1992
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.1365-3032.1992.tb01193.x
Subject(s) - biology , zoology , tephritidae , ingestion , weight loss , liquid diet , desiccation , relative humidity , ecology , botany , pest analysis , obesity , biochemistry , physics , ethanol , endocrinology , thermodynamics
During long post‐feeding periods, adult tephritid flies (and apparently other non‐blood feeding Diptera and even Hymenoptera) engage in behaviour consisting of oral extrusion and aeration of liquid droplets of varying size (‘bubbling’), proboscis pumping, and occasional deposition of regurgitate on the substrate that is followed by subsequent re‐ingestion. Unlike evaporative cooling, which occurs in some insects when heat‐stressed, these regurgitation behaviours take place regularly at moderate temperatures. To our knowledge, the significance of these behaviours has not been studied. We suggest that through bubbling behaviour, fully gorged Rhagoletis pomonella (Walsh) (Diptera: Tephritidae) flies eliminate excess water by evaporation to concentrate nutrients suspended in dilute solution, and release crop volume to allow resumption of fluid feeding or minimize the water load while foraging for other resources. Fly weights were measured continuously during pre‐ and post‐feeding periods and in relation to occurrence of regurgitation behaviours. Fly weight losses during pre‐feeding were an order of magnitude lower than post‐feeding weight losses when flies exposed regurgitated liquid crop contents to air. During a bout of droplet extrusions, lasting on average 23 min, weight loss averaged 66% of the weight of liquid ingested by a fly in the preceding meal. Fly weight loss while bubbling was significantly correlated with duration of bubbling, temperature and relative humidity during post‐feeding, and initial fly weight (adj. R 2 = 0.95). Fly age, volume of liquid ingested and rate of pre‐feeding weight loss did not significantly improve predicted weight loss through bubbling. Findings are discussed in relation to other behaviours adopted by fluid‐feeding insects to eliminate excess water.