Changes in the protein concentration and volume of the haemolymph in relation to yolk deposition, ovariectomy, allatectomy, and cautery of the median neurosecretory cells in Melanoplus sanguinipes

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Abstract
Protein concentration and hemolymph volume may change with no apparent relation to one another in normal, ovariectomized, allatectomized and median-neurosecretory-cell-cauterized (mNSC-cauterized) females. Protein levels in the hemolymph are more meaningfully expressed in terms of the total protein content. In normal females, fluctuations in hemolymph volume tend to parallel changes in protein concentration during the first and subsequent gonotrophic periods. Significantly less protein accumulates during the latter periods. The suggestion that these fluctuations partly reflect changes in the vitellogenic requirements of the oocytes is supported by the finding that both volume and protein concentration increase significantly after ovariectomy. Allatectomy or mNSC cautery prevents normal accumulation of protein in hemolymph. In allatectomized females, the slight increase in protein concentration is accompanied by a decline in hemolymph volume. Cautery of the mNSC, provided it is performed within 3 h of emergence, results in a low protein concentration but has no effect on the hemolymph volume. The observations are discussed in terms of the corpora allata and mNSC control of hemolymph protein synthesis.