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The chemical composition of haemolymph in insects and some other arthropods, in relation to their phylogeny

1963; Pergamon Press; Volume: 9; Issue: 2 Linguagem: Inglês

10.1016/0010-406x(63)90016-1

1879-3029

D. W. Sutcliffe,

Insect Utilization and Effects

1. The aim of this study is to suggest that in pterygote insects a basic type of haemolymph is discernible, and that this basic type was modified in several ways and on a number of occasions during the evolution of the Insecta. 2. One organic and six inorganic components in insect haemolymph are considered which respect to their potential contributions to the total osmotic activity of the haemolymph—the concentration of each component is expressed as a percentage of the total osmolar concentration. 3. It is suggested that a high proportion of chloride is characteristic of the Exopterygota, whereas a low proportion of chloride is characteristic of the Endopteerygota. 4. In the majority of exopterygote insects, sodium and chloride each account for major proportions of the total osmolar concentration. Potassium, calcium, magnesium, inorganic phosphate and free amino acids account for only minor proportions of the total. It is suggested that haemolymph with this composition represents the basic type of haemolymph in pterygote insects. This type of haemolymph is very similar to that found in modern representatives of phylogenetically related groups, viz. an apterygote insect, a chilopod and diplopod. Hence it is suggested that the basic haemolymph type found in modern pterygotes represents the haemolymph of the ancestral stock of pterygote insects. 5. In endopterygone insects, with a monophyletic origin from the ancestral pterygote stock, the basic haemolymph type is modified by a reduction of chloride and an increase of organic acids, including a tendency to increase the proportion of free amino acids. 6. In certain exopterygote and endopterygote insects the haemolymph is radically modified in various ways. These are regarded as specializations. One type of specialization appears to be characteristic of the Lepidoptera and Hymenoptera, where inorganic ions contribute only a very minor proportion of the total haemolymph osmolar concentration; free amino acids, and, in some cases, other organic components, contribute the major proportion of the haemolymph total.