Functional organization of the macroglomerular complex related to behaviourally expressed olfactory redundancy in male cabbage looper moths

Abstract. The neurophysiological bases for behaviourally expressed olfactory redundancy in the sex pheromone communication system of the cabbage looper moth, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae), were examined by coupling the cut-sensillum extracellular recording technique with a highly specific neuronal marking method for moth peripheral receptors. In seventy-two antennal sensilla, axonal pathways of cobalt-stained neurones could be traced into the male-specific macroglomerular complex in the antennal lobe. In T. ni males this comprises five glomeruli, two of which are subdivided into morphologically, and in some instances functionally identifiable, regions. Axonal arborizations of forty-eight neurones (single stainings) showed high fidelity (98%) for containment within a specific glomerulus or glomerular subdivision, and the neuropil targeted seemed to be related to the specificity of a neurone to a particular female-emitted sex pheromone component (27-12:Ac, Z7-14:Ac, Z9-14:Ac, 12:Ac, 11–12:Ac, Z5-12:Ac), or to a behavioural antagonist (Z7-12:OH). Double (twenty-one) and multiple stainings (three) showed axons projecting into two or more glomeruli, respectively, with 100% fidelity for the component-specific glomerulus or glomerular subdivision to be targeted. We suggest that the potential for a single minor component to cross-stimulate two or more neurones within a sensillum may enable partial blends to continue to provide sensory input into all of the pheromone-processing glomeruli of the complex. Our interpretation is that redundancy occurs at the receptor level on neighbouring dendrites, and thus allows various four-component partial blends to evoke full pheromone-mediated behaviour.     

Large Hawk‐Cuckoo Hierococcyx sparverioides parasitism on the Chinese Babax Babax lanceolatus may be an evolutionarily recent host–parasite system

We documented brood parasitism by the poorly studied Large Hawk‐Cuckoo on a previously unknown host species, the Chinese Babax. Furthermore, we describe a new egg colour for the Large Hawk‐Cuckoo. The parasitism rate of Chinese Babax nests over 4 years was 6.9% (11 of 159 nests), with significant temporal variation. The Large Hawk‐Cuckoo laid immaculate white eggs that appeared non‐mimetic to the blue Babax eggs, an impression that was confirmed by avian visual modelling. Nevertheless, most Cuckoo eggs were accepted by the host, suggesting that this host–parasite system may be evolutionarily recent.     

Agrotis segetum雄蛾触角叶性信息素反应神经元对电刺激触角神经的反应

为探讨电刺激Agrotis segetum雄蛾触角神经是否可以作为MGC中神经元的识别手段,采用细胞内电生理记录方法,共记录34个对性信息素有反应的MGC神经元,并测试了其中12个神经元对性信息素刺激的反应,22个神经元对性信息素刺激和电刺激的反应。结果表明,MGC神经元对性信息素及电刺激的反应模式基本一致,为一种双相反应模式。两种刺激方式均能诱导出兴奋反应,电刺激得到的兴奋反应比由信息素刺激引起的要短;MGC神经元对两种刺激的超极化反应（抑制反应）幅度影响没有显著性差别,在电刺激实验的22个神经元上,超极化反应幅度和抑制时间都与神经元本身放电频率有一定的相关性。超极化反应是在LN参与下一定的神经回路对刺激所产生的反应而形成的。这提示两种刺激所作用的神经回路应是一致的,但从整个实验过程记录到的神经元情况来看,还须进一步结合形态学实验来验证电刺激触角神经作为MGC神经元的识别手段。     

Exorhopala ruficeps (Balanophoraceae): morphology and transfer to Helosis

Exorhopala ruficeps is a rare parasitic plant of the family Balanophoraceae, endemic to the north-western part of Peninsular Malaysia. It was originally described in Rhopalocnemis and later placed in a new monotypic genus on the basis of the exogenous origin of its inflorescences. A new collection of material enabled a detailed morphological study, the results of which are presented here. Inter alia, it is documented that the inflorescences originate endogenously as in all other Balanophoraceae. However, no volva is formed and the tuber-tissue covering the emerging inflorescence crumbles into pieces. The inflorescence and flower characters established here are neither in full accordance with Rhopalocnemis nor do they justify a genus of its own, but instead place the species in Helosis , which thus becomes a genus of transpacific distribution. The new combination is Helosis ruficeps (Ridl.) R. K. Eberwein.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 513–517.     

Biodiversity indicators in European ground waters: towards a predictive model of stygobiotic species richness

1. Estimates of species richness obtained from exhaustive field inventories over large spatial scales are expensive and time-consuming. For this reason, efficiency demands the use of indicators as 'surrogates' of species richness. Biodiversity indicators are defined herein as a limited suite of taxonomic groups the species richness of which is correlated with the species richness of all other taxonomic groups present in the survey area.
2. Species richness in ground water was assessed at different spatial scales using data collected from six regions in Europe. In total, 375 stygobiotic species were recorded across 1157 sites and 96 aquifers. The taxonomic groups collected from more than one site and with more than two species (Oligochaeta, Gastropoda, Cyclopoida, Harpacticoida, Ostracoda, Isopoda, Amphipoda, Bathynellacea and Acari) were used to develop nonparametric models to predict stygobiotic biodiversity at the aquifer scale.
3. Pair-wise correlations between taxonomic groups were low, i.e. variation in species richness of a single taxonomic group did not usually reflect variation of the other groups. In contrast, multiple regressions calculated between species richness of any combination of taxa and extra-group species richness along the six regions resulted in a number of significant relationships.
4. These results suggest that some taxonomic groups (mainly Copepoda and Amphipoda and, to a lesser extent, Oligochaeta and Gastropoda) combined in different ways across the regions, were good biodiversity indicators in European groundwater ecosystems. However, the uneven distribution of taxonomic groups prevented selection of a common set of indicators for all six regions. Faunal differences among regions are presumably related to both historical and ecological factors, including palaeogeography, palaeoecology, geology, aquifer fragmentation and isolation, and, less clearly, anthropogenic disturbance.     

Three new species of deep‐sea Gromia (Protista,Rhizaria) from the bathyal and abyssal Weddell Sea,Antarctica

We describe three new species of the genus Gromia from bathyal and abyssal depths in the Weddell Sea. The new species are characterized by a combination of morphological and molecular criteria. All three species possess a distinct oral capsule and a layer of ‘honeycomb membranes’, which form the inner part of the organic test wall. Both these features are typical of gromiids. Their identification as gromiids is confirmed by analyses of partial small subunit ribosomal DNA (SSU rDNA) gene sequences. Gromia marmorea sp. nov. is a rounded species with a prominent oral capsule and a characteristically mottled appearance. In Gromia melinus sp. nov. , the test surface exhibits a polygonal pattern of ridges, with a layer of clay particles coating the surface between the ridges. Gromia winnetoui sp. nov. represents an elongate morphotype in which the organic test is enclosed within an agglutinated case, a feature previously unknown in gromiids. Phylogenetic analysis using the maximum‐likelihood method revealed that all three species form distinct clades, reflecting the morphological differences among Weddell Sea species, as well as between deep‐water Southern Ocean Gromia and previously described gromiids. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 157 , 451–469.