Study On Inter-specific Competition And Inter-colony Competition From Different Colonies For Odontermes Formosanus (Isoptera: Termitidae)

Odontermes formosanus (Shiraki) is an important pest of agronomic crops, plantations and forestry, and badly destroys earthen dikes and dams. The colony competition and inter-speific competition from different colonys for O. formosanus were studied from the perspective of the behavior in the thesis. Furthermore, new indicators were used on quantifying and contrasting the level of competition, the major results are summarized as following:1. Study on inter-colony competition for O. formosanus in different colony ageThere was obvious conflictive between groups of O. formosanus in different colony age, no matter the same or different castes they all could not be compatible. When termits from different colonies were blended together, they displayed an immediate mutual aggressiveness. The struggle times presented the decreasing trend, finally almost no struggle happened. The same regardless of castes test different manifestations of the struggle of all, O. formosanus in growing prosperity colony age (colony A) was stronger than in decaying colony age (colony B). O. formosanus colony body in different age was impossible to achieve reliance struggle succession. There were no possibility that termites of O. formosanus in different colony age amalgamation by accident at all in the nature, the amalgamation way could not be the race multiplying natural way at all.2. Study on inter-colony competition for O. formosanus in the same colony ageThe research showed that caste compatibility between workers and soldiers from the same age colony displayed an immediate mutual aggressiveness, when the blending proportion was 1:1, the struggle was more fierce. Soldiers from Colony C were relatively competitive, with the compatibility between different castes study the results. Different castes compatibility study, the two colonies displayed an immediate mutual aggressiveness, but calming down 0.5h after they were blended together. The reason for the struggle decline was not the fierce struggle at the beginning, that led to the rapid physical decline and high mortality rate caused by, because 24 h later, the highest mortality rate was also lower than 30%, the impact to whole colony was not that great. The results showed that O. formosanus in the same colony age had low-intensity struggling phenomenon. It was possible for O. formosanus in the same colony age amalgamation by accident at all in the nature, the amalgamation way could be the race multiplying natural way.3. Study on factors impacting inter-colony competition for O. formosanusThe results showed that difference between the termite total had impacted on convening soldiers only. And numbers of soldier impacting on competition had reflected in higher ratio of soldiers, quantity did not differ greatly, most often dig through tunnels; the higher ratio of soldiers was quite different, distance soldiers walking were significantly longer because the larger soldier quantities, casual than the corresponding distribution when a danger happened, there were bound to relatively individuals, rushing from the long distance; When soldiers from two colonies were very different in number, numbers of soldiers rushing in the same time were different. Therefore, differences of single soldier beating time were significant. Tunnel width had greatly restricted the speed of soldiers rushing to danger place, because the tunnel width made a decision that termits could only on theirs separate way; Therefore, the colony body which could convene more soldier in a relatively short time was more competitive. In the case of food, colonies external expansion trend was not obvious, developed around the nearest food source, on the contrary, colonies without feeding expanded from the center outward for the purpose of divergence, or numbers of main tunnel branch were more than the former, but the difference between the two was not significant.4. Study on inter-speific competition between O. formosanus and two other speciesthe experiment was about the compatibility of O. formosanus with two other termites, the Formosan subterranean termite, Coptotermes formosanu and another subterranean termite, Reticulitermes chinensis. Set termites of two different species in one glass Petri dish acording 5 blending proportion to observe theirs combat. After the experiment we found that: Though both species displayed an immediate mutual aggressiveness, O. formosanus workers were much more aggressive than C. formosanus and R. chinenesis workers. Likewise, aggressive behaviour of soldiers and workers was independent. These results indicated that mixed colonies of these species could not be formed in nature by chance, and O. formosanu was likely to prevail in areas where it has established.