| Adult females and larvae were reared on logs, semi-artificial diets and ambrosia fungi for observing the biological traits, studying the effects of different plants, temperatures, ambrisia fungi and semi-artificial diets on the development and fecundity of Xylosandrus germanus (Blandford), and the results were as follows:1. It cost at least 23 days from female adult intruding to offspring emerging while they were reared on grapevines under dark condition at 25℃, and the emerging peak was on the 4th day to the 9th day. The intense emerging time was from 13:00 to 14:00 within a day. The offspring numbers were more as the grapevines diameter were in the range of 1.1cm to 1.7cm.2. While the adult females of X. germanus (Blandford) were reared on 15 different species logs of grapevine, Chinese small apple, citrus, shaddock, plum, pear, Chinese cherry, hibiscus, calyx anthus, loquat, peach, jujube, deodar cedar, sweet osmanthus and Chinese tea under dark condition at 25℃, the selective test results showed that, the insect prefered to select grapevine and could reproduce the most number of offspring on it, liked to select citrus, shaddock, Chinese small apple and sweet osmanthus trees, might select pear, loquat and jujube but couldn't reproduce offspring. The nonselective trial results were almost the same as that of selective, except the difference on sweet osmanthus tree.3. Adult females could reproduce successfully on all different semi-artificial diets under dark condition at 25℃. The effects on fecundity of X. germanus rearing on different semi-artificial diets made of grapevine, Chinese small apple, pear, citrus, shaddock, jujube, loquat and sweet osmanthus tree powder were non-significant and that was significant when rearing on semi-artificial diets with different water ratio and different compositions. The fecundity of rearing adult females on semi-artificial diets with the composition of 10 grapevine powder:1 beer yeast powder:1 saccharose:1.5 soluble starch:20 distill water were the biggest,81.00 offsprings per female; The fecundity was the smallest with 24.00 offsprings per female when the ratio was 1.5:1; The fecundity was 39.25 offsprings per female when reared on semi-artificial diets with the composition of 10 grapevine powder: 1.5 soluble starch:20 distill water.4. The adult females and larvae were fed with Acremonium kiliense and Ambrosiella hartigii in Petri dishes, and the adult females were reared on semi-artificial diet in glass tubes, the development and fecundity of X. germanus (Blandford) were studied in the laboratory at six constant temperatures between 16 and 31℃as well as at five constant temperatures between 16 and 28℃, respectively.The results showed that developmental duration for every different stage increased with temperature at the range from 16 to 28℃, and the developmental duration at 16℃was 3.85 times more than that at 28℃, however, it prolonged at 31℃except the pupal stage. Developmental duration for the larva was the longest of all the stages at all temperatures tested, and was more than half of that from egg stage to adult emergence. The lower temperature thresholds for development ranged from 11.0℃(pupal stage) to 12.7℃(egg to adult), and the upper temperature thresholds ranged from 33.48℃(egg to adult) to 35.03℃(larval stage). The optimum temperature for the larval stage was 26.44℃. The thermal constants were lowest for the egg (61.5DD) and highest for the larvae (189.7DD),304.76DD were required to complete development from egg to adult. Survivorship of all stages increased along with temperature, and from egg to adult it increased from 53.3% at 16 to 68.3% at 25℃, and decreased from 35.0% at 28℃to 3.3% at 31℃. The larvae almost failed to pupate at 31℃. Fecundity increased along with temperature from 16 to 25℃, and was greatest at 25℃with 121.5 offspring per female, almost 2.5 times more than that at 16℃and decreased at 28℃. The female/male sex ratio was smallest (9.6:1) at 16℃and biggest (23.3:1) at 25℃, and above 19.0:1 at all the rest temperatues. There were 4 generations in Ya'an city (Sichuan province) when adult females were reared on semi-artificial diets in field continuously.5. The larvae could complete development feeding on 3 different species of ambrosia fungi in Petri dishes under the dark condition at 25℃, but the effects were different significantly. The larvae grew fastest with the shortest duration (12.4d) feeding on A. hartigii, while grew slowest (18.9d) feeding on Fusarium sp.. The survival rate of feeding on Fusarium sp. was the lowest with 12.3%, significantly lower than that feeding on A. hartigii and A. kiliense. The adult female could reproduce all male offsprings feeding on these 3 different species of ambrosia fungi on semi-artificial diets under the dark condition at 25℃, the time for laying egg was the earliest when feeding on A. kiliense, and the highest offspring number was 12 males per female feeding on A. hartigii. The female longevity was very long, which died after all the male offspring were dead.
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