柑桔潜叶蛾产卵行为对叶片选择的研究

研究春梢、夏梢和秋梢期间,柑桔潜叶蛾雌成虫产卵行为对新梢叶片长度的选择。根据模型分析,春梢期产卵选择的最佳叶长为1.6m),夏、秋梢期选择产卵的最佳叶长为2.4cm。     

美丁鱼逆游

美丁鱼生活在亚马逊河流域。这种鱼全身彩装,美丽无比,却十分懒惰且毫无坚持力,游动时慢慢腾腾,遇到障碍物,不是努力超越,而是折身返回。每到秋天来临,美丁鱼便会逆流而上,游到西特湖产卵生子。人     

葛洲坝下游:中华鲟的生境危机

葛洲坝坐落在湖北宜昌市,它截断长江已经有28年了。最后的中华鲟适应了这个巨大的变化,在宜昌的江底找到了新的产卵场,在日益恶化的生境中继续顽强生存。     

鲇人工繁殖技术的初步研究

为了给鲇的苗种繁育提供理论资料，作选择性腺发育成熟的鲇鱼，采用脑垂体以及三种不同品种激素进行催产，受精卵采取环道流水孵化．结果表明：性腺发育良好的亲鱼．时催产激素要求不严．单独使用，混合使用均可；用棕榈皮制作鱼巢，可减少落地卵；在催情配组时应考虑雌、雄鲇个体大小的协调性，否则，雌鲇的产卵效率会受到影响；鲇鱼苗互相残食严重。在鲇出苗后3～5d，开口饲料质量好坏尤其重要；鲇在水温20～26℃范围内，约经48h鱼苗开始孵化出膜．     

揭秘德国肉鸡33天速成背后

过去,一只鸡的寿命约是15年,它们身形健壮且适应力强。历史上,罗马曾把鸡视作圣物,日耳曼人也将它们作为陪葬品;在漫长的水上航行中,鸡还被看作紧急条件下的救命食物。时至今日,在现代化养鸡业的蹂躏之下,这个物种的生存环境正在不断恶化。无论外在环境多么恶劣,一只产卵鸡一年之内都要生出300只鸡蛋。它们生     

蜜蜂"舞蹈室"的妙用

由于蜂后忙于产卵而无暇顾及其他,所以无法指挥蜜蜂采蜜,但蜜蜂采蜜时的环境条件复杂而又无法预料,例如哪儿有花蜜,哪朵花分泌的花蜜多,哪儿的花蜜更好吃?另外还要考虑天气的变化等。那么如何调动蜜蜂到花蜜多又好且安全的蜜源去采蜜     

昆虫的“亲子情”

许多昆虫在生育下一代之前,对"子女"的食物就已经作出周密的准备。有一种沙蜂为了给后代觅取食物,在炎热的沙地上与狼蛛(lang zhu)进行生死搏(bo)斗,用尾针注射毒液将狼蛛麻醉,并经过长途拖运,击退拦路抢劫者,千辛万苦地把食物运到目的地。     

从海龟识途说动物的特异功能

路遥知马力在自然界中,有些动物的能力让人叹为观止,是人类永远也不可能具备的。印度洋里的绿龟大约每四年都要跋涉数百千米回到相同的海滩产卵。法国科学家最近证实,海龟具有这种奇妙的识途本领的原因,是由于它能依靠地球磁场定位。     

Biological activities of chamomile （Matricaria chamomile） flowers＇ extract against the survival and egg laying of the cattle fever tick （Acari Ixodidae）

In the present work, the potential of acaricidal activity of chamomile flowers＇ extract was studied against engorged Rhipicephalus annulatus tick under laboratory condition. For this purpose, the engorged females ofRhipicephalus annulatus were exposed to two-fold serial dilutions of chamomile flowers＇ extract （0.5%, 1.0%, 2.0%, 4.0% and 8.0%） using ＂dipping method＂ in vitro. The engorged ticks were immersed in different plant dilutions （five ticks for each dilution） for l rain and they were immediately incubated in separate Petri dishes for each replicate at 26℃ and 80% relative humidity. Mortality rate for each treatment was recorded 5 d after incubation. The mortality rate caused by different dilutions of chamomile flowers＇ extract ranged from 6.67% to 26.7%, whereas no mortality was recorded for non-treated control group. The mass of produced eggs varied from 0.23 g （in 8.0% solution） to 0.58 g （in control）, with no statistical differences between the treatments and control （/＇〉0.05）. Also the chamomile flowers＇ extract in highest concentration used （8.0%） caused 46.67% failure in egg laying in engorged females while no failure was observed for non-treated control group. Macroscopic observations indicated that in effective concentrations of plant （4.0% and 8.0%）, patchy hemorrhagic swelling appeared on the skin of treated ticks. The results presented for the first time in this study imply that chamomile may be considered as a promising plant for biocontrol of cattle fever tick disease in the field condition.