Abstract:

Objective: This study aims to investigate the sources of the proctodeal trophallaxis substances of Reticulitermes chinensis,and provide reference for further study on the mechanism of trophallaxis and control of the termite. Method: The morphological changes of the alimentary canal in different types of individuals were compared by microanatomy. The contents of protein in the paunch (P3) and colon (P4) + rectum (P5) in different instar workers were measured,and the sources of the proctodeal trophallaxis substances of R. chinensis were determined. The relationship between "provider" and "recipient" of different instar workers in the proctodeal trophallaxis was inferred by counting the proportion of different instar workers in different nests. Result: 1) The P3 of the queen was the most developed among different types of individuals and its contents were viscous and yellowish brown color. The P3 of the worker was relatively developed and its contents were viscous and yellowish brown color. The P3 of soldier was also relatively developed and its contents were thick and white color. The P3 of 3^rd instar larva was still at the early stage and its contents were thick and white color. The contents of P3 were sticky and light yellow color in alate. 2) The P1,P4 and P5 of workers,soldiers,alates and queens were all similar in size with each other,suggesting that there is little relationship between the sources of the trophallaxis substances and the sizes of P1,P4 and P5. There was no significant difference in the size of the P3 among workers,soldiers and queens,but the color of the contents was obviously different. Thus,the color of the contents in P3 could be used as a morphological index to judge the "provider" or "recipient" of proctodeal trophallaxis. 3) In 2^nd-6^th instar workers,the protein content of P3 was higher than that of P4+P5,respectively. It was suggested that protein content in different parts of hindgut could also be used as a judging index of the trophallaxis substances origination. (4) The 2^nd-3^rd instar workers accounted for more than 50% of the total number of workers. With the development of colony,the proportion of the 4rd instar worker increased slightly. Conclusion: P3 is the main source site of the proctodeal trophallaxis substance. The 2^nd and the 3^rd instar workers are the main "provider" of proctodeal trophallaxis substances.

Key words: Reticulitermes chinensis, Rhinotermitidae, proctodeal trophallaxis, P3, provider