Hemolymph of reproductives of Solenopsis invicta (Hymenoptera: Formicidae) -: amino acids, proteins and sugars

Free amino acid composition and carbohydrate and protein concentration of the hemolymph of the pupal and adult stages of reproductives of Solenopsis invicta are presented. The physico-chemical properties of the hemolymph differ between both sexes of fire ants during development. Male alates (459 mmol/kg) have a higher osmolality than pupae (388 mmol/kg). Osmolality during the pupal stage was 428 mmol/kg, decreasing to 354 mmol/kg soon after de-alation and increasing again to 463 mmol/kg in active queens. The hemolymph of newly eclosed adults was more basic than the pupa and older adults. The pH of the hemolymph ranged from 6.40 to 6.71 for males and 6.47 to 7.01 for females. An increase in the carbohydrate and protein content was found for both sexes after emergence. Newly de-alated females had a decrease in their carbohydrate titers, although no changes were found in the protein concentration. An increase in the total free amino acid concentration was recorded for males after emergence, while changes in females were noted only after de-alation. However, females had a 2.7-fold increase in the free amino acid pool after they de-alated, with proline, glutamine and taurine showing the highest increase. Changes in the organic composition and in the physicochemical properties of the hemolymph of S. invicta are discussed in regard to the physiological processes involved in the maturation of the reproductives of this insect. (C) 2002 Elsevier Science Inc. All rights reserved.