Effects of methoxychlor on larval development of mud-crab and blue crab

Laboratory experiments were conducted to determine the effects of methoxychlor on the larval development of the mud-crab, Rhithropanopeus harrisii, and the commercial blue crab, Callinectes sapidus, from the time of hatching until the 1st crab stage was reached. The effect of a range of concentrations of methoxychlor on survival of larvae of C. sapidus and R. harrisii was determined, as well as the concentrations which were sublethal and lethal. Since concentrations as low as 1.3, 1.6 and 1.9 ppb (μg l^?1) methoxychlor were acutely toxic to C. sapidus larvae, and it took a concentration as high as 7.0 ppb to be acutely toxic to R. harrisii larvae, it was concluded that C. sapidus larvae were much more sensitive to methoxychlor than R. harrisii larvae. Zoeal and total development to the 1st crab stage of R. harrisii and C. sapidus were prolonged in relation to increased concentrations of methoxychlor. The developmental stages in which larvae were particularly sensitive varied in the two species. Methoxychlor residues of R. harrisii and C. sapidus larvae reared in concentrations of methoxychlor were determined.     

Effects of mirex on the larval development of two crabs

The effects of mirex, a chlorinated hydrocarbon used to kill the imported red ant, Solenopsis saevissima richteri, on the complete larval development of two crabs, Rhithropanopeus harrisii and Menippe mercenaria are described. The duration of developmental stages of Rhithropanopeus and the total time of development is generally lengthened with an increase in concentration of mirex from 0.01 to 10.0 ppb. There are highly significant differences between survival of larvae in the control and in each concentration of mirex. In Menippe, there were no pronounced differences in duration of developmental stages with increased concentrations of mirex, but the percentage of extra 6th zoeae was greater as concentrations were increased. There was differential survival of the developmental stages in relation to concentration of mirex, and Menippe larvae were much more sensitive to mirex than Rhithropanopeus larvae, especially in the megalopal stage. Residue analysis revealed that Menippe concentrates mirex more efficiently during development to crab stages than does Rhithropanopeus.     

Sublethal effects of insect growth regulators upon crab larval behavior

Both swimming speeds and phototaxis by the four larval stages of the crab Rhithropanopeus harrisii were monitored upon chronic exposure to sublethal concentrations of the insect growth regulators methroprene (Altosid^R: ZR-515), hydroprene (Altozar^R: ZR-512) and dimiline (TH-6040). Larvae were reared under conditions of salinity (20orbo) and temperature (25°C) which produce the greatest developmental success. Sublethal concentrations of methroprene had no effect on swimming rates or phototaxis as compared to the acetone control larvae. For hydroprene, swimming rates by stage I, II and III zoeae were unaffected while a significant increase in swimming speeds occurred in Stage IV zoeae exposed to concentrations of 0.05 and 0.1 ppm. Only Stage III zoeae exposed to 0.l ppm showed a significant decrease in the level of positive phototaxis. Dimilin was much more potent, as significant increases in swimming speeds occurred in Stage I, II and III zoeae, with 0.3 ppb being the lowest effective concentration. Although swimming by Stage IV zoeae was unaffected, phototaxis was altered at concentrations as low as 0.1 ppb. Concentrations, which alter behavior, are related to levels which are reported to control mosquitoe larvae.     

Kepone effects on larval development of mud-crab and blue-crab

Laboratory experiments wer conducted to determine the effects of Kepone on the larval development of the mud-crab,Rhithropanopeus harrisii, and the commercial blue crab,Callinectes sapidus, from the time of hatching until the 1st crab stage was reached. Differential survival ofR. harrisii from hatching to 1st crab stage occurred in a range of 35 to 125 ppb Kepone, whereas differential survival ofC. sapidus over the same period of development occurred in a range of 0.1 to 1.0 ppb. Statistical analysis indicated that, for every 10 ppb Kepone added, duration from hatching to 1st crab stage ofR. harrisii was increased by 0.391±0.043 days; whereas for each increase of 0.1 ppb, the duration from hatching to 1st crab stage ofC. sapidus is prolonged by 0.38±0.10 days. The 1st and 2nd zoeal stages ofR. harrisii were the most sensitive developmental stages to Kepone, but the 1st zoeal stage ofC. sapidus was not sensitive, statistically, to any concentration of Kepone tested. In zoeal stages II, III and IV, there were significant increases in mortality ofC. sapidus over the previous stage in all media tested.     

Determination of hexachlorobenzene and mirex in fatty products.

A procedure is described for the isolation and cleanup of hexachlorobenzene (HCB) and mirex in fats and oils for gas-liquid chromatographic (GLC) analysis. The fat or oil is distributed on unactivated Florisil, and the HCB and mirex are eluted with acetonitrile. The pesticides are then partitioned into petroleum ether. Elution through activated Florisil with methylene chloride-hexane (20+80) is used for the final cleanup. HCB and mirex are then measured by GLC, using the appropriate electron capture conditions with a 15% OV-210 column for HCB and a 3% OV-101 column for mirex. The method demonstrates recoveries greater than 90% for HCB and mirex and allows screening at or below the 0.1 ppm level in fats with a 3 mg fat injection.     

The effects of three phthalate esters on the larval development of the grass shrimp Palaemonetes pugio (Holthuis)

The effects of three phthalic acid esters, dimethyl phthalate (DMP), di-n-butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) on survival and development rate of larvae of the grass shrimp Palaemonetes pugio were investigated. Only 100 ppm DMP and 10 to 50 ppm DBP were acutely toxic to the larvae. DMP at a concentration of 100 ppm significantly increased the duration of larval development to the first postlarval stage. DEHP concentrations up to 1 ppm (the solubility limit of this ester) were without effect on either survival or development rate of the larvae. Phthalate esters were not detectable at or above the 2 ppm level in the tissues of larvae chronically exposed to phthalates for the duration of larval development, suggesting active metabolism of phthalates by this species.     

幼虫密度对小菜蛾生长发育和繁殖的影响

为明确小菜蛾幼虫密度对其种群增长的影响,在室内条件下[温度(22±1)℃,RH70%~80%,光周期12L∶12D]对不同幼虫密度[1头.皿1、10头.皿1、20头.皿1、30头.皿1、40头.皿1(直径为9 cm)]饲养的小菜蛾生长发育及繁殖进行了研究。结果表明,幼虫密度对小菜蛾幼虫、蛹的发育历期和存活率、蛹重及成虫生殖等有显著影响。幼虫和蛹历期均以10头.皿1处理最短,且随幼虫密度增加而显著延长。幼虫至蛹的存活率以10头.皿1、20头.皿1处理较高,显著高于1头.皿1和40头.皿1处理。蛹重以1头.皿1处理最重,并随幼虫密度的增加而显著变轻。不同幼虫密度下羽化的成虫畸形率差异显著,以10头.皿1处理最低,其余随幼虫密度的增加而升高。成虫产卵量以1头.皿1处理最高,随着幼虫密度增加,产卵量逐渐下降。雌、雄蛾寿命分别以40头.皿1、10头.皿1处理最长,密度过高时或过低雌雄蛾寿命显著缩短。生命表分析表明,幼虫密度对小菜蛾种群增长指数影响显著,以10头.皿1处理种群增长指数最高,幼虫密度过高或过低,种群增长指数下降。因此,幼虫密度是影响小菜蛾种群增长的重要因子之一。     

利用机器视觉识别麦粒内米象发育规律与龄期

研究麦粒内部粮虫生长规律,判断粮虫所处发育龄期,为制定合理的防治措施提供科学依据,具有重要的社会经济价值。该文提出一种基于机器视觉的麦粒内米象变态发育规律及龄期识别研究方法。试验利用Micro-CT获取侵染麦粒投影数据,应用z-FDK(z-Feldkamp-Davis-Kress)算法重建出侵染粒的二维图像,利用图像分割及形态学方法得到虫体图像。提取了虫体的8个二维特征、4个三维特征、7个不变矩特征和7个基于灰度共生矩阵的显著性纹理特征,构成26维原始特征空间。根据不同龄期虫体特征的变化,研究米象在麦粒内的变态发育规律。利用模拟退火算法(simulated annealing algorithm,SAA)优化虫体原始特征,构建了优化后的10维特征空间。运用人工蜂群算法(artificial bee colony,ABC)优化支持向量机(support vector machine,SVM)的惩罚因子和径向基核函数参数,实现对麦粒内米象所处发育龄期的自动判别。试验结果表明,米象变态发育规律与实际情况一致,且对米象龄期的识别率达到97%,可有效判别出侵染粒中米象所处发育龄期。     

纳米硅对人参生长发育的影响

以人参为试验材料,设置6个浓度硅处理：0 g/L(CK)、0.03 g/L(T1)、0.06 g/L(T2)、0.09 g/L(T3)、0.12g/L(T4)、0.15 g/L(T5),用以探究不同硅浓度对人参生长发育的影响及变化趋势。结果表明,不同浓度施硅对人参的叶长、茎长、根长、叶宽、茎粗、根粗、生物量变化均有积极作用,施硅对促进人参生长的最佳供硅浓度为0.09 g/L。施硅对促进人参光合能力的提升有积极作用,胞间CO₂浓度在T2处理下达到最大值,较CK增高4.01%;气孔导度在T3处理下达到最大值,较CK增高100%;净光合速率在T3处理下达到最大值,较CK增高136.47%;蒸腾速率在T3处理下达到最小值,较CK降低27.54%。不同浓度施硅可以通过提高活性氧防御系统的酶活性(过氧化物酶含量)以及减轻细胞损伤程度(丙二醛含量)来增强人参根、茎、叶的整体抗性强度。不同浓度施硅可以引起人参体内硅含量的增加和持续积累,施硅增强人参硅素吸收的最优处理为0.09 g/L。以不同部位来看,追肥处理的人参硅素分布为叶>根>茎;以不同时期来看,绿果期结束、红果...     

6－二甲氨基嘌呤对牛卵母细胞孤雌发育的影响

本研究系统探讨了 6-二甲氨基嘌呤 ( DMAP)对牛卵母细胞孤雌发育的影响。牛卵母细胞体外成熟 2 4 ,2 6,2 8或 30 h后 ,先用含 7%乙醇的培养液激活处理 5min,然后在含 2 mmol/L DMAP的培养液中培养 3h,或直接在培养液中进行培养。结果发现 ,经 2 mmol/L DMAP培养处理 3h的卵母细胞的激活分裂率和囊胚发育率均明显高于未处理的卵母细胞 ,特别是对于体外成熟 2 4 h和 2 6h的卵母细胞差异更为显著。如若在 DMAP处理的基础上同时加入 5μg/m L的细胞松驰素 ( CB) ,卵母细胞激活后的囊胚发育率则得到进一步提高 ( 48.7%比 37.5% )。研究结果表明 ,DMAP和 CB对卵母细胞激活后的孤雌发育有促进作用 ,并能降低卵龄所引起的激活效果差异     

Effects of oak barrens habitat management for Karner blue butterfly (Lycaeides samuelis) on the avian community

The federally endangered Karner blue butterfly (Lycaeides samuelis) is the focal species for a conservation plan designed to create and maintain barrens habitats. We investigated whether habitat management for Karner blue butterflies influences avian community structure at Fort McCoy Military Installation in Wisconsin, USA. From 2007 through 2009 breeding bird point count and habitat characteristic data were collected at 186 sample points in five habitat types including two remnant barrens types, barrens habitat restored from woodland and managed specifically for the Karner blue butterfly, and two woodland habitat types. Although the bird community of managed barrens was not identical to the communities of remnant barrens, the Field Sparrow (Spizella pusilla), a species of conservation concern, and sparse canopy associated bird species, such as the Baltimore Oriole (Icterus galbula) and Eastern Bluebird (Sialia sialis) were predicted to occupy managed barrens and remnant barrens in similar proportions. Adjacent habitat was the most influential factor in determining the community of bird species using the managed barrens. In Wisconsin, and likely throughout the range of the Karner blue butterfly, management for the butterfly creates habitat that attracts a bird community similar to that of remnant barrens, and benefits several avian species of conservation concern. Additionally, the landscape context surrounding the managed habitat influences avian community composition. Managed barrens that are adjacent to remnant barrens, rather than adjacent to woodland habitats, have the highest potential for conserving barrens breeding birds.     

Effects of environmental characteristics of aquaculture sites on the quality of cultivated Newfoundland blue mussels (Mytilus edulis)

This study examined (1) the effects of seasonal and annual environmental characteristics (temperature, chlorophyll content, salinity, microbial water quality, and algal lipid composition) in four aquaculture locations on the quality (meat content, shell size, and microbial and lipid compositions) of cultivated blue mussels and (2) the optimum harvest time for premium-quality mussels. Seasonal and annual temperature fluctuation of the seawater in the aquaculture sites significantly (P < 0.05) affected their salinity, microbial content, and algal fatty acid compositions, which in turn affected the quality attributes of cultivated mussels. The optimum growth period in terms of meat content (4-5 g) and shell size (50-60 mm) can be achieved within 1 year of cultivation. Because the cultivated mussels examined in this study never reached the maximum microbial load limits (10(5) or log 5 colony-forming units/g of meat), they can be harvested throughout the year. Meanwhile, no significant (P > 0.05) annual changes were observed in total omega-3 polyunsaturated fatty acids content of cultivated mussels. Nonetheless, the optimum harvest time may be April-June for eicosapentaenoic acid (EPA) rich mussels and September-October for docosahexaenoic acid (DHA) rich mussels in terms of fatty acid proportions; however, June may be the best month for the highest concentrations of both EPA and DHA.     

外源酶和辣椒素对黑水虻处理厨余垃圾效率及幼虫生长的影响

该研究从厨余垃圾成分和黑水虻幼虫的生活习性入手,通过添加外源酶以提升黑水虻处理厨余垃圾的效率和虫体质量。向厨余垃圾中添加淀粉酶和过氧化氢酶,以加速其中的淀粉分解,利于幼虫生长;并在2或5 d龄期幼虫培育阶段向厨余垃圾中添加辣椒素刺激幼虫进食,以期提高厨余垃圾的处理速率和养殖虫体的粗蛋白质量等。研究表明,向厨余垃圾中添加质量分数0.1‰的α-淀粉酶和0.01‰的过氧化氢酶,并在5 d龄期幼虫培育阶段添加12.5‰的辣椒素可提高黑水虻处理厨余垃圾的效率、虫体鲜质量和干质量、粗蛋白和粗脂肪质量,黑水虻处理厨余垃圾速率较对照提高了6.49%,其虫体鲜质量和干质量分别提高了29.70%和38.22%、粗蛋白质量提高了18.81%、粗脂肪质量提高了20.97%。微量外源酶（α-淀粉酶和过氧化氢酶）添加并在5 d龄期幼虫培育阶段加以辣椒素刺激,可显著提升黑水虻处理厨余垃圾的速率、虫体鲜质量和干质量以及粗蛋白和粗脂肪质量（P<0.05）,研究结果可为厨余垃圾高效利用和高蛋白饵料基质的培育提供参考依据。     

Effects of prescribed fire and fire surrogates on floral visiting insects of the blue ridge province in North Carolina

Pollination by insects in forests is an extremely important process that should be conserved. Not only do pollinating insects help to maintain a diversity of plants within forests, but they also aid in pollinating crops found near forested land. Currently, the effects of various forest management practices on floral visiting insect abundance or diversity is unknown, so we investigated how prescribed burning, mechanical shrub control, and combination of the two affected abundance of floral visiting insects. We caught 7921 floral visitors from four orders and 21 families. Hymenoptera was the most abundant and diverse order, with Halictidae being the most abundant family. A total of 45 species of Hymenoptera representing six families were captured. We caught seven families and 35 species of Lepidoptera, six families and 33 species of Coleoptera, and two families and 13 species of Diptera. Most floral visitors were captured in the mechanical shrub control plus prescribed burn treatments, while lower numbers were caught on the mechanical shrub control only, prescribed burn only and control treatments. Overall species richness was also higher on mechanical plus burn treatments. Total pollinator abundance and the abundance of most orders and families was correlated with decreased tree basal area and increased percent herbaceous plant cover. Our study shows that floral visitors increased in abundance and species richness most from forest disturbance that reduced the density of overstory trees and increased the amount of herbaceous plant growth.     

补光光源对AM真菌生长发育的影响

温室条件下,研究不同补光光源对丛枝菌根(Arbuscular mycorrhizae,AM)真菌Glomus mosseae生长发育的影响。结果表明：不同补光光源的光谱不同,对菌根共生体生长发育的影响不同,以农艺钠灯作为补光光源处理的宿主植物的光合速率及可溶性糖含量高于其它两种光源处理,综合比较菌根长度、根外菌丝量及孢子数三项指标,以农艺钠灯作为补充光源对真菌G. mosseae的生长发育最为有利。金属卤灯、荧光灯两处理宿主植物中氮、磷浓度高于农艺钠灯处理,可能对菌根真菌的生长发育有不利影响。因此,工厂化AM菌剂生产中,如果需要补充光照,应以农艺钠灯作为补光光源。