Three-dimensional visualization of termite (Apicotermitinae) enteric valve using confocal laser scanning microscopy

Humivorous termites are dominant members of tropical rainforest soil communities. In the soil-feeding subfamily Apicotermitinae (Termitidae), the enteric valve connecting the first section of the hindgut to the paunch often displays a complex sclerotized armature everted towards the lumen of the paunch. This structure is central in termite taxonomy but its function remains hypothetical. Here, we evaluate the potential of confocal laser scanning microscopy to provide detailed imaging of the valve of Anoplotermes parvus, by comparison with bright-field microscopy and scanning electron microscopy. We detected a strong far-red emission of the enteric valve armature that sharply contrasted with the surrounding tissues, providing a convenient method to highlight minute structural elements of the valve and its three-dimensional structure. The method is easy to use and is applicable to standard archival material as demonstrated by images of enteric valves of four other Apicotermitinae species. It may represent a valuable asset for the study of termite enteric valves, for the purpose of taxonomy or functional morphology.