Comparative Morphology Of Termite Gut And Its Value On Systematics (Isoptera)

This thesis is focused on the morphological differences of alimentary canal among different castes of termite and the systematic significance of these differences. Worker (pseudergate) and soldier are two selected termite castes to reveal the morphological variations of alimentary canal. The ultrastructures of gizzard in worker (pseudergate) are studied as well.Termite is one of the main economic pests in the world. In order to reveal the systematic significance of the morphological variation of gut in different castes of termites, soldier and worker (pseudergate) castes of eight termite species belonging to four families in China (lower 4, higher 4) were selected in this study, the gizzard ultrastructure of worker (pseudergate) caste of ten termite species were studied by SEM. the results are as follow:1. the differences of gut characters between soldier and worker:1) the gut morphological differentiation between soldier and worker are closely to their phylogenic position, the higher the position of termites, the more obvious of gut morphological differences, and also show changes in gut spatial structure.2) in the lower termites that lack of worker caste, the total length of the gut and the percentage of foregut, midgut, and hindgut in soldier and worker and so on, there are no significant differences. the total length of gut and hindgut percentage are longer than soldier in the more higher species that exist the true worker caste termites. It indicate that the caste emerging the true worker and labor grade play an important role in the gut of termite caste differentiation.3) the capsule length of the soldier, the degree of development of the digestive gland, have distinct effects on the gut morphological character.2. the ultrastracture of gizzard of worker:1) the ultrastructure of gizzard can reflect to the phylogeny in termite, the gizzard ultrastructural features can reflect the phylogenic relationship of termites, distantly related species have significant difference in the shape of the column of gizzard, the cuticular in the column and pulvillus cuticle character, inner cuticle character and so on .2) diet differentiation is closely to the ultrastructure of the gizzard in the lower Hodotermitidae and Kalotermidae species, their teeth that column I and II in gizzard cuticle are also closely to the wood feeding, and with the differentiation of the rich diet of termites they gradually degraded and disappeared;3) the setae on the column and pulvilli may have important value in the termite phylogeny, show an evolutional trend in status. scattered and isolated seta– scalelike -pectinated setae– pectinated setae absent. pectinated setae on pulvillusⅠandⅡtrend to be elongate.The photographs of scanning electron micrograph of gizzard are attached.All the species are deposited in the Entomological Museum of Shanghai, Chinese Academy of Sciences.