Linkichnus Terebrans New Ichnogenus et Ichnospecies,an Insect Boring from the Late Triassic of the Germanic Basin,Southern Germany

The proposed new ichnotaxon Linckichnus terebrans n. ig. et isp., is a small test-tube shaped boring produced by insects in a sphenophyte stem and occurs in Upper Triassic (Keuper) terrestrial deposits.     

合欢吉丁Agrilus subrobustus Saunders的学名厘定及危害特性

【目的】本文对危害合欢Albizia julibrissin Durazz的钻蛀性害虫合欢吉丁Agrilus subrobustus Saunders各虫态形态特征及危害特性进行了研究与描述,深入探索其虫道三维结构,以期为合欢吉丁的发生监测及防治提供依据。【方法】查阅相关文献,记述整理了合欢吉丁学名的变化过程,详细地观察并描述了剖腹卵、幼虫、蛹、成虫的形态特征;首次研究总结其坑道系统的各指标特点:虫口密度、坑道长宽、侵入孔特征、蛹室特征、羽化孔特征等,明确了完整虫道的发生发展规律;基于坑道拍照、各向量指标测量,对坑道进行科学手绘,使用Autodesk Maya软件完成合欢吉丁完整虫道的三维重建。【结果】合欢吉丁幼虫细长、乳白色,蛹为裸蛹。成虫铜绿色具金属光泽,观察对比其前胸背板长宽比、盘区和肩前隆脊形态,前胸腹板突形状,鞘翅柔毛分布位置,阳茎形态等特征,结合文献,明确其学名为Agrilus subrobustus Saunders。合欢吉丁主要危害树干韧皮部及木质部,具向阳性;在树皮下钻蛀坑道,侵入孔圆形,不超过1 mm;蛹室米粒状,多位于木质部,少数位于韧皮部;羽化孔"D"型;坑道形状具有规律性,可分为3种:"Z"字型及其变型,密集上下迂回型,椭圆或近半圆型坑道。【结论】基于形态特征的详细描述、学名厘定,有利于合欢吉丁的鉴定及学名的正确使用;完整虫道的复原便于在非成虫期结合寄主种类鉴定害虫种类、评估虫口密度和危害程度,为合欢吉丁的监测提供了具体的判别方法,为化学防治、生物防治等提供参考与技术支持。     

The origin of herbivory on land： Initial patterns of plant tissue consumption by arthropods

The early fossil record of terrestrial arthropod herbivory consists of two pulses. The first pulse was concentrated during the latest Silurian to Early Devonian （417 to 403 Ma）, and consists of the earliest evidence for consumption of sporangia and stems （and limited fungivore borings）. Herbivorization of most of these tissues was rapid, representing 0 to 20 million-year （m.y.） lags from the earliest occurrences of these organs in the fossil record to their initial consumption （Phase 1）. For approximately the next 75 m.y., there was a second, more histologically varied origination and expansion of roots, leaves, wood and seeds, whose earliest evidence for herbivorization occurred from the Middle-Late Mississippian boundary to the Middle Pennsylvanian （327 to 309 Ma）. The appearance of this second herbivory pulse during the later Paleozoic （Phase 2） is accompanied by major lags of 98 to 54 m.y. between times of appearance of each of the four organ and tissue types and their subsequent herbivory. Both pulses provide a context for three emerging questions. First is an explanation for the contrast between the near instantaneous consumption of plant tissues during Phase 1, versus the exceptionally long lags between the earliest occurrences of plant tissues and their subsequent herbivorization during Phase 2. Second is the identity of arthropod herbivores for both phases. Third is the cause behind the overwhelming targeting of seed-fern plant hosts during Phase 2. Regardless of the answers to these questions, the trace fossil record of plant-arthropod associations provides primary ecological data that remain unaddressed by the body-fossil record alone.     

Reproductive cycle of the coral-excavating sponge Thoosa mismalolli (Clionaidae) from Mexican Pacific coral reefs

Abstract. Individuals of the recently described demosponge Thoosa mismalolli are common on Mexican Pacific coral reefs, excavating burrows in living corals and in other calcareous substrata. To better understand the propagative abilities of this sponge, we conducted a histological study over an 18-month period (May 2007–November 2008) to identify sexual and asexual reproductive structures. Members of the species are viviparous and hermaphroditic, with various developmental stages of oocytes, spermatic cysts, and embryos co-occurring in the mesohyl for most of the year. This nearly continuous reproductive activity intensified during the warm season. Fertilization was internal, and embryos developed inside the parental sponge to produce an unciliated hoplitomella larva, characterized by a peculiar siliceous skeleton. In addition to the sexually generated larvae, adults of T. mismalolli formed gemmules for asexual reproduction. Gemmules occurred within the mesohyl during all months of the year, but were most abundant in the coldest months. This combination of sexual and asexual processes enables individuals of T. mismalolli to reproduce almost continuously. This strategy may facilitate both long-term persistence within reefs and effective dispersal between distant reefs.     

NEW ENDOLITHIC CYANOBACTERIA FROM THE ARABIAN GULF. I. HYELLA IMMANIS SP. NOV.1

Hyella immanis, a new species of endolithic cyanobacterium that penetrates carbonate ooid sand grains in the Arabian/Persian Gulf, is formally described. Natural populations of the new taxon were sampled in moving ooid shoals at four locations along the east coast of Saudi Arabia, together with seven other endolithic taxa. The new species was isolated, and its properties were studied under experimental conditions. Small reproductive cells (baeocytes) exhibited positively phototactic gliding motility following release. In culture they grew into colonies forming isodiametric packages (prevalent on agar) and distinct pseudofilaments (prevalent in liquid culture). Carbonate penetration of the cultured strain in liquid culture proceeded at a rate of up to 10 μ· d^?1. Agitation of cultures with magnetic stirrers enhanced the frequency of borings and the initial boring rates, but it had no effect on the continuing boring activity. A fossil counterpart of the new species was identified in Upper Proterozoic (700–800 million years old) silicified oolitic and pisolitic rocks of East Greenland.     

硅介导的水稻对二化螟幼虫钻蛀行为的影响

采用对二化螟敏感(汕优63)和中抗(盐丰47)的水稻品种,设置硅酸钙处理,观察二化螟蚁螟和三龄幼虫在不同处理稻茎上的钻蛀率、蛀入率和蛀入耗时,同时测定不同处理植株的硅细胞数量及植株与土壤的二氧化硅含量,旨在明确水稻施用硅肥对二化螟幼虫钻蛀行为的影响以及这种影响在不同龄期幼虫和不同抗虫性水稻品种间是否存在差异。蚁螟和三龄幼虫钻蛀率随硅肥施用量增加而降低(幅度为5%—28%)。蚁螟蛀入率在硅肥处理之间和水稻品种之间均没有差异;三龄幼虫蛀入率随硅肥施用量增加而显著下降10%—40%,盐丰47上的蛀入率显著低于汕优63(差异10%—30%)。蚁螟蛀入耗时随硅肥施用量增加而显著延长,三龄幼虫蛀入耗时与品种抗性有显著关系。稻茎硅含量随硅肥施用量增加而增大,并且与三龄幼虫蛀入率呈负相关、与三龄幼虫蛀入耗时呈正相关关系。因此,施用硅肥可直接抑制二化螟幼虫钻蛀,蛀入耗时的延长可间接地延长幼虫暴力于其它防治措施的时间;施用硅肥对三龄幼虫成功蛀入的影响大于对蚁螟的影响;相对于抗虫品种,施用硅肥能在更大程度上增强感虫品种对二化螟幼虫钻蛀行为的抑制作用。     

Precipitation of iron in windowpane oyster shells by marine shell‐boring Cyanobacteria

Shells of windowpane oyster [Placuna placenta (L)] in the intertidal zone of the Zuari estuary, Goa, were often found to be black in color. Microscopical observation of partially decalcified shells showed the presence of cyanobacterial filaments encrusted with black precipitate. Microchemical test (Prussian blue reaction) and wavelength dispersive x‐ray analysis confirmed this precipitate to be of iron. Mineralogical studies of this black precipitate, using x‐ray diffraction and scanning electron microscopy, suggested the presence of iron as iron oxides. The cyanobacteria from such black shells were cultured in enriched seawater medium. In this medium also they precipitated iron as confirmed by Prussian blue reaction. They were identified as Plectonema terebrans Born et Flah and Phormidium sp.     

Stem tissue mass density is linked to growth and resistance to a stem‐boring insect in Alternanthera philoxeroides

To investigate how stem anatomical structure is linked to growth and resistance to stem‐boring insects in a herbaceous species, six populations of alligatorweed (Alternanthera philoxeroides) were grown in a common garden. Stem growth rate (GR) of A. philoxeroides and pupation rate as an estimate of resistance to a stem‐boring insect (Agasicles hygrophila) were quantified. Stem tissue mass density (TMD) was measured and stem anatomical traits were analysed on cross‐sectional areas (CSA). Stem TMD was positively correlated with resistance (i.e. negatively correlated with pupation rate) and negatively correlated with GR. Stem cortex CSA (%) and vascular bundle (VB) density (no./mm²) were positively related to stem TMD and negatively related to pupation rate. The GR was positively related to VB CSA (%) and negatively related to VB density. These results suggest that stem TMD, which results from a high fraction in cortex CSA and high VB density, is a key determinant of resistance to a stem‐boring specialist in A. philoxeroides. The high resistance of plants with higher stem TMD may partially impose a cost to plant growth.     

双钩异翅长蠹幼虫声学特征初探

害虫声音探测技术作为一门新兴的技术方法,在植物检疫领域具有独特的应用优势。为了此技术在口岸植物检疫推广应用积累经验、提供思路,本文利用声音探测技术对口岸经常截获的检疫性有害生物双钩异翅长蠹幼虫的取食和爬行声信号进行了研究。双钩异翅长蠹幼虫取食和爬行声信号差异显著:其取食声信号脉冲持续时间主要分布于32-41 ms区间,主频小于2.5 KHz,信号频率主要分布于334.10-813.50 Hz;其爬行声信号时域特征无明显规律,主频大约为0.2 KHz,频率主要分布于140.60-382.20 Hz。     

寄生性天敌蒲螨研究进展

蒲螨属Pyemotes具有特殊的生活史和形态特征,是多种害虫的体外寄生性天敌。蒲螨属的种按照形态等特点分为2个组,分别为小蠹蒲螨组(Pyemotes scolyti group)和球腹蒲螨组(Pyemotes ventricosus group)。国内外对蒲螨毒素的研究较多,已知其属于昆虫神经毒素,能使寄主昆虫永久性麻痹,有些种类还能引起人类和动物皮炎。对一些种类蒲螨的毒素组成成分、毒素基因重组技术等进行研究,对蒲螨毒素基因的优化和重组仍将是进一步研究的热点。作为一类很有潜能的害虫天敌资源,蒲螨应用方面的报道还较少,国外集中在麦蒲螨对仓储害虫和红火蚁的防治方面;我国有利用小蠹蒲螨防治小蠹虫的报道,近年来防治双条杉天牛取得成功,表明其用于防治钻蛀性害虫特别是蛀干害虫和地下害虫前景良好,因此,应对蒲螨蒲螨寄主谱、寄主选择机理、寄生机理等进行深入研究。