| The biology of Diorhabda elongata deserticola Chen (Coleoptera:Chrysomelidae) was studied,including reproductive behavior, parasitism, development threshold temperature and the effective accumulated temperarure. The spatial pattern and its mechanisms and ecological function were investigated.The male took an active role in copulation, which can be dividede into three periods of precopulation,copulation and postcopulation.The average duration of copulation was 48.67min. The leaf beetle copulated and oviposited multiply. The female initiated oviposition 28 hours after copulation with the fecundity of 141 eggs. Egg color turned from fresh yellow into grey-white 31min after oviposited.The mating individuals peaked in three periods of 8:00-11:00, 14:00-17:00 and 20:00-22:00, while the oviposition behavior peaked in 11:00-14:00 and 17:00-20:00.There are two species of parasitoids with Mymaridae(Mymaridae,Hymenoptera) from eggs, and Erynniopsis antennata Rondani from(Tachnidae,Diptera) larvae and adults. The highest parasitization rate of eggs can reach to 52.6%, while that of larvae was much lower.The development threshold temperature and the effective accumulated temperarure were studied under the temperature regime of 18℃,20℃,23℃,28℃ and 33℃. The results showed that only egg could complete development under 18℃. The development threshold temperatures were 10.30,13.10,10.51,16.35℃ each for egg, larva, pupa and pre-oviposition period of adult. The effective accumulated temperarure were 112.16, 201.02, 110.22, 58.40day degrees respectively basing on the linear regression method.Adults were gregarious both in the Fukang Tamarix Reserves and Wujiaqu Reservoir, but the aggregation was stronger in the former than the latter. The aggregation was the result of its behavior and the response to the host plants in Fukang Tamarix Reserves. While in Wujiaqu Reservoir the aggregation was probably the result of environment. The adult aggregation was beneficial to the multiple copulation and oviposition.
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