Non‐host plant essential oil volatiles with potential for a ‘push‐pull’ strategy to control the tea green leafhopper,Empoasca vitis

The tea green leafhopper, Empoasca vitis Göthe (Hemiptera: Cicadellidae), is an economically important pest of tea crops, Camellia sinensis (L.) O. Kuntze (Theaceae), in China. The use of non‐host plant essential oils for manipulation of E. vitis was investigated for potential incorporation into a ‘push‐pull’ control strategy for this pest. The effectiveness of 14 plant essential oils in repelling E. vitis was investigated in laboratory assays. Rosemary oil, geranium oil, lavender oil, cinnamon oil, and basil oil repelled leafhoppers in a Y‐shaped olfactometer. We also compared the efficacy of these five plant essential oils to repel E. vitis in the presence of a host plant volatile‐based leafhopper attractant, (Z)‐3‐hexenyl acetate, in a tea plantation. In the treatment combination, four plates (north, south, east, and west) treated with an essential oil surrounded a central sticky plate treated with (Z)‐3‐hexenyl acetate. Fewer E. vitis were found on the plates treated with rosemary oil (12.5% reduction) than on the four water‐sprayed control treatment plates surrounding a central plate with (Z)‐3‐hexenyl acetate. We compared the distribution of E. vitis on the plates, and the relative numbers of E. vitis on each plate were compared with similar plates in the control treatment. When four plates treated with rosemary oil surrounded a central (Z)‐3‐hexenyl acetate‐treated plate, the distribution of E. vitis on the different plates changed significantly compared with that of the control. Relatively fewer E. vitis were found on the east (13.0% reduction) rosemary oil‐treated plates and more E. vitis (11.3% increase) were found on the central attractant‐treated plate. Our findings indicate that rosemary oil is a promising leafhopper repellent that should be tested further in a ‘push‐pull’ strategy for control of E. vitis.     

Secondary galling: a novel feeding strategy among ‘non‐pollinating’ fig wasps from Ficus curtipes

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Multiple gene analyses reveal extensive genetic diversity among ‘Candidatus Phytoplasma mali’ populations

This study focused on evaluating the genetic diversity among ‘Candidatus Phytoplasma mali’ (‘Ca. P. mali’) populations in orchards of north‐western Italy, where apple proliferation (AP) disease is widespread and induces severe economic losses. ‘Ca. P. mali’ was detected through restriction fragment length polymorphism (RFLP) analysis of PCR‐amplified 16S rDNA in 101 of 114 samples examined. Collective RFLP patterns, obtained by restriction analyses of four amplified genomic segments (16S/23S rDNA, PR‐1, PR‐2 and PR‐3 non‐ribosomal region, ribosomal protein genes rplV‐rpsC and secY gene), revealed the presence of 12 distinct genetic lineages among 60 selected representative ‘Ca. P. mali’ isolates, underscoring an unexpected high degree of genetic heterogeneity among AP phytoplasma populations in north‐western Italy. Prevalence of distinct genetic lineages in diverse geographic regions opens new interesting avenues for studying the epidemiology of AP disease. Furthermore, lineage‐specific molecular markers identified in this work could be useful for investigating the biological life cycle of ‘Ca. P. mali’.     

A revision of the sauropod dinosaur genus ‘Bothriospondylus’ with a redescription of the type material of the Middle Jurassic form ‘B. madagascariensis’

Abstract: The sauropod dinosaur ‘Bothriospondylus’, originally named on the basis of Late Jurassic remains from England, is demonstrated to be invalid, and the characters used to diagnose it are shown to be obsolescent features which are widespread throughout Sauropoda. Material referred to this genus spans a temporal range from the Middle Jurassic until the early Late Cretaceous and has been described from five different countries, across three continents. These remains represent a wide array of sauropod groups, comprising non‐neosauropod eusauropods, a macronarian, titanosauriforms (including at least one definite brachiosaurid) and a rebbachisaurid. The type material of the Middle Jurassic ‘B. madagascariensis’ represents a derived non‐neosauropod eusauropod and possesses two potential autapomorphies. However, as a result of the fragmentary nature of the material and the uncertainty surrounding its association, a new taxon is not erected. Of the numerous specimens referred to ‘Bothriospondylus’, however, several remains are considered diagnostic: Ornithopsis hulkei (Early Cretaceous, UK), Lapparentosaurus madagascariensis (Middle Jurassic, Madagascar) and Nopcsaspondylus alarconensis (early Late Cretaceous, Argentina). At least three types of sauropod were present in the Bathonian (Middle Jurassic) of north‐west Madagascar, with a basal eusauropod (Archaeodontosaurus), a more derived eusauropod (‘B. madagascariensis’) and a titanosauriform (Lapparentosaurus) all approximately contemporaneous. Palaeocontinental reconstructions suggest that Middle Jurassic Madagascan sauropods would still have been capable of global biotic interchange, and this is perhaps reflected in their diverse assemblage. Re‐evaluation of these Malagasy forms has shed new light on this important time period in sauropod evolution.     

Chrysanthemum expressing a linalool synthase gene ‘smells good’, but ‘tastes bad’ to western flower thrips

Herbivore‐induced plant volatiles are often involved in direct and indirect plant defence against herbivores. Linalool is a common floral scent and found to be released from leaves by many plants after herbivore attack. In this study, a linalool/nerolidol synthase, FaNES1, was overexpressed in the plastids of chrysanthemum plants (Chrysanthemum morifolium). The volatiles of FaNES1 chrysanthemum leaves were strongly dominated by linalool, but they also emitted small amount of the C11‐homoterpene, (3E)‐4,8‐dimethyl‐1,3,7‐nonatriene, a derivative of nerolidol. Four nonvolatile linalool glycosides in methanolic extracts were found to be significantly increased in the leaves of FaNES1 plants compared to wild‐type plants. They were putatively identified by LC‐MS‐MS as two linalool–malonyl–hexoses, a linalool–pentose–hexose and a glycoside of hydroxy–linalool. A leaf‐disc dual‐choice assay with western flower thrips (WFT, Frankliniella occidentalis) showed, initially during the first 15 min of WFT release, that FaNES1 plants were significantly preferred. This gradually reversed into significant preference for the control, however, at 20–28 h after WFT release. The initial preference was shown to be based on the linalool odour of FaNES1 plants by olfactory dual‐choice assays using paper discs emitting pure linalool at similar rates as leaf discs. The reversal of preference into deterrence could be explained by the initial nonvolatile composition of the FaNES1 plants, as methanolic extracts were less preferred by WFT. Considering the common occurrence of linalool and its glycosides in plant tissues, it suggests that plants may balance attractive fragrance with ‘poor taste’ using the same precursor compound.     

A radicle solution: morphology and biomechanics of the Eucalyptocrinites ‘root’ system

Eucalyptocrinites is one the most common and familiar mid‐Palaeozoic crinoids and is the exemplar of a form with dendritic radicular holdfasts. American museums have hundreds of specimens of Eucalyptocrinites holdfasts from the Silurian Waldron Shale of Indiana and Kentucky, USA. The radix (‘root’) system of Eucalyptocrinites can be described as comprised of links (branches) that meet at nodes. Measured values include the x‐ and y‐coordinates of the nodes, the distances of the nodes from the stem, the angles between branches, branch length and branch width. Rose diagrams show clearly that the root systems are not isotropic but have preferred orientations. Branch angles are highly variable, but cluster around 60 degrees. Branch lengths and distal branch widths are relatively constant, but branch width increases variably towards the column. The branching pattern can be modelled as a self‐similar (‘fractal’) structure. Several specimens labelled as Eucalyptocrinites show a distinct fivefold symmetry without branching and very likely represent a different taxon. The Eucalyptocrinites radix system, along with the probably stiff dististele, most likely functioned as a rigid plate that resisted rotational forces due to currents acting on the crown. Upstream radicles experienced tension, whereas downstream roots were compressed. This force distribution may explain the observed anisotropies in radix morphology. The ‘roots’ of Eucalyptocrinites and other crinoids have long been compared with the root systems of plants. Although there are superficial similarities, there are fundamental differences.     

‘Bioethical Realism’: A Framework for Implementing Universal Research Ethics

Implementation of existing ethical guidelines for international collaborative medical and health research is still largely controversial in sub‐Saharan Africa for two major reasons: One, they are seen as foreign and allegedly inconsistent with what has been described as an ‘African worldview’, hence, demand for their strict implementations reeks of ‘bioethical imperialism’. Two, they have other discernible inadequacies – lack of sufficient detail, apparent as well as real ambiguities, vagueness and contradictions. Similar charges exist(ed) in other non‐Western societies. Consequently, these guidelines have been correctly judged as an inadequate response to the complex and ever shifting dilemmas met by researchers and research regulators in the field. This paper proposes a framework for effective implementation of existing guidelines without much worry about bioethical imperialism and other inadequacies. This framework is proposed using an analogy of Legal Realism, specifically its key assertions on how, in reality, judicial systems operate using general legal rules to settle specific cases. Legal realists assert that in judicial decision‐making, general legal rules do not totally dictate court decisions in specific cases. This analogy is used to coin a new term, ‘Bioethical Realism.’ The framework suggests that local Research Ethics Committees ought to be construed as analogues of judicial courts with the resulting implications. Consequently, just like legal rules are general rules that do not always dictate court decisions, similarly international bioethical guidelines are general ethical rules that should not always dictate local RECs’ decisions and such decisions (ought to) enjoy considerable immunity from outsiders.     

The AAT1 locus is critical for the biosynthesis of esters contributing to ‘ripe apple’ flavour in ‘Royal Gala’ and ‘Granny Smith’ apples

The ‘fruity’ attributes of ripe apples (Malus × domestica) arise from our perception of a combination of volatile ester compounds. Phenotypic variability in ester production was investigated using a segregating population from a ‘Royal Gala’ (RG; high ester production) × ‘Granny Smith’ (GS; low ester production) cross, as well as in transgenic RG plants in which expression of the alcohol acyl transferase 1 (AAT1) gene was reduced. In the RG × GS population, 46 quantitative trait loci (QTLs) for the production of esters and alcohols were identified on 15 linkage groups (LGs). The major QTL for 35 individual compounds was positioned on LG2 and co‐located with AAT1. Multiple AAT1 gene variants were identified in RG and GS, but only two (AAT1‐RGa and AAT1‐GSa) were functional. AAT1‐RGa and AAT1‐GSa were both highly expressed in the cortex and skin of ripe fruit, but AAT1 protein was observed mainly in the skin. Transgenic RG specifically reduced in AAT1 expression showed reduced levels of most key esters in ripe fruit. Differences in the ripe fruit aroma could be perceived by sensory analysis. The transgenic lines also showed altered ratios of biosynthetic precursor alcohols and aldehydes, and expression of a number of ester biosynthetic genes increased, presumably in response to the increased substrate pool. These results indicate that the AAT1 locus is critical for the biosynthesis of esters contributing to a ‘ripe apple’ flavour.     

Detection and Identification of ‘Candidatus Phytoplasma prunorum’, ‘Candidatus Phytoplasma mali’ and ‘Candidatus Phytoplasma pyri’ in Stone Fruit Trees in Poland

A survey was made to determine the incidence of phytoplasmas in 39 sweet and sour cherry, peach, nectarine, apricot and plum commercial and experimental orchards in seven growing regions of Poland. Nested polymerase chain reaction (PCR) using the phytoplasma‐universal primer pairs P1/P7 followed by R16F2n/R16R2 showed the presence of phytoplasmas in 29 of 435 tested stone fruit trees. The random fragment length polymorphism (RFLP) patterns obtained after digestion of the nested PCR products separately with RsaI, AluI and SspI endonucleases indicated that selected Prunus spp. trees were infected by phytoplasmas belonging to three different subgroups of the apple proliferation group (16SrX‐A, ‐B, ‐C). Nucleotide sequence analysis of 16S rDNA fragment amplified with primers R16F2n/R16R2 confirmed the PCR/Restriction Fragment Length Polymorphism (RFLP) results and revealed that phytoplasma infecting sweet cherry cv. Regina (Reg), sour cherry cv. Sokowka (Sok), apricots cv. Early Orange (EO) and AI/5, Japanese plum cv. Ozark Premier (OzPr) and peach cv. Redhaven (RedH) was closely related to isolate European stone fruit yellows‐G1 of the ‘Candidatus Phytoplasma prunorum’ (16SrX‐B). Sequence and phylogenetic analyses resulted in the highest similarity of the 16S rDNA fragment of phytoplasma from nectarine cv. Super Queen (SQ) with the parallel sequence of the strain AP15 of the ‘Candidatus Phytoplasma mali’ (16SrX‐A). The phytoplasma infecting sweet cherry cv. Kordia (Kord) was most similar to the PD1 strain of the ‘Candidatus Phytoplasma pyri’ (16SrX‐C). This is the first report of the occurrence of ‘Ca. P. prunorum’, ‘Ca. P. mali’ and ‘Ca. P. pyri’ in naturally infected stone fruit trees in Poland.     

Why coelacanths are not ‘living fossils’

A series of recent studies on extant coelacanths has emphasised the slow rate of molecular and morphological evolution in these species. These studies were based on the assumption that a coelacanth is a ‘living fossil’ that has shown little morphological change since the Devonian, and they proposed a causal link between low molecular evolutionary rate and morphological stasis. Here, we have examined the available molecular and morphological data and show that: (i) low intra‐specific molecular diversity does not imply low mutation rate, (ii) studies not showing low substitution rates in coelacanth are often neglected, (iii) the morphological stability of coelacanths is not supported by paleontological evidence. We recall that intra‐species levels of molecular diversity, inter‐species genome divergence rates and morphological divergence rates are under different constraints and they are not necessarily correlated. Finally, we emphasise that concepts such as ‘living fossil’, ‘basal lineage’, or ‘primitive extant species’ do not make sense from a tree‐thinking perspective. Editor's suggested further reading in BioEssays Tree thinking for all biology: the problem with reading phylogenies as ladders of progress Abstract     

Spectral effects of LEDs on chlorophyll fluorescence and pigmentation in Phalaenopsis ‘Vivien’ and ‘Purple Star’

We examined the effect of light emitting diode (LED) lighting in greenhouse facilities on growth, chlorophyll fluorescence and pigmentation in Phalaenopsis ‘Vivien’ and ‘Purple Star’ under purpose‐built LED arrays yielding c. 200 µmol m^?2 s^?1 at plant height for 14 h per day and 24/18°C day/night temperature, respectively, from January to April 2013. The light treatments were (1) 40% blue in 60% red (40% B/R), (2) 0% blue in 100% red (0% B/R) and (3) white LEDs with 32% blue in white (32% B/W, control), with background daylight under shade screens. The plants were harvested twice for leaf growth and pigmentation. There was no clear pattern in the spectral effect on growth since the order of leaf size differed between harvests in March and April. F_v/F_m was in the range of 0.52–0.72, but overall slightly higher in the control, which indicated a permanent downregulation of PSII in the colored treatments. The fluorescence quenching showed no acclimation to color in ‘Purple Star’, while ‘Vivien’ had lower ETR and higher NPQ in the 40% B/R, resembling low light acclimation. The pigmentation showed corresponding spectral response with increasing concentration of lutein while increasing the fraction of blue light, which increased the light absorption in the green/yellow part of the spectrum. The permanent downregulation of PSII moved a substantial part of the thermal dissipation from the light regulated NPQ to non‐regulated energy losses estimated by Φ_NPQ and Φ_NO and the difference found in the balance between Φ_PSII and Φ_NPQ in ‘Vivien’ disappeared when Φ_NO was included in the thermal dissipation.     

Genetic influences on ‘environmental’ factors

Childhood environment, social environment and behavior, leisure time activities and life events have been hypothesized to contribute to individual differences in cognitive abilities and physical and emotional well‐being. These factors are often labeled ‘environmental’, suggesting they shape but not reflect individual differences in behavior. The aim of this study is to test the hypothesis that these factors are not randomly distributed across the population but reflect heritable individual differences. Self‐report data on Childhood Environment, Social Environment and Behavior, Leisure Time Activities and Life Events were obtained from 560 adult twins and siblings (mean age 47.11 years). Results clearly show considerable genetic influences on these factors with mean broad heritability of 0.49 (0.00–0.87). This suggests that what we think of as measures of ‘environment’ are better described as external factors that might be partly under genetic control. Understanding causes of individual differences in external factors may aid in clarifying the intricate nature between genetic and environmental influences on complex traits.     

Altered sensitivity to ethylene in ‘Tardivo’, a late‐ripening mutant of Clementine mandarin

‘Tardivo’ mandarin is a mutant of ‘Comune’ Clementine with a delay in peel degreening and coloration, allowing late harvesting. In this work, we have explored if the late‐harvesting phenotype of ‘Tardivo’ mandarin is related to altered perception and sensitivity to ethylene. The peel degreening rate was examined after a single ethephon treatment or during a continuous ethylene application in fruits at two maturation stages. In general, ethylene‐induced peel degreening was considerably delayed and reduced in fruits of ‘Tardivo’, as well as the concomitant reduction of chlorophyll (Chl) and chloroplastic carotenoids, and the accumulation of chromoplastic carotenoids. Analysis of the expression of genes involved in Chl degradation, carotenoids, ABA, phenylpropanoids and ethylene biosynthesis revealed an impairment in the stimulation of most genes by ethylene in the peel of ‘Tardivo’ fruits with respect to ‘Comune’, especially after 5 days of ethylene application. Moreover, ethylene‐induced expression of two ethylene receptor genes, ETR1 and ETR2, was also reduced in mutant fruits. Expression levels of two ethylene‐responsive factors, ERF1 and ERF2, which were repressed by ethylene, were also impaired to a different extent, in fruits of both genotypes. Collectively, results suggested an altered sensitivity of the peel of ‘Tardivo’ to ethylene‐induced physiological and molecular responses, including fruit degreening and coloration processes, which may be time‐dependent since an early moderated reduction in the responses was followed by the latter inability to sustain ethylene action. These results support the involvement of ethylene in the regulation of at least some aspects of peel maturation in the non‐climacteric citrus fruit.     

‘Candidatus Phytoplasma asteris’ and ‘Candidatus Phytoplasma aurantifolia’, New Phytoplasma Species Infecting Apple Trees in Iran

During several surveys in extensive areas in central Iran, apple trees showing phytoplasma diseases symptoms were observed. PCR tests using phytoplasma universal primer pairs P1A/P7A followed by R16F2n/R16R2 confirmed the association of phytoplasmas with symptomatic apple trees. Nested PCR using 16SrX group‐specific primer pair R16(X)F1/R1 and aster yellows group‐specific primer pairs rp(I)F1A/rp(I)R1A and fTufAy/rTufAy indicated that apple phytoplasmas in these regions did not belong to the apple proliferation group, whereas aster yellows group‐related phytoplasmas caused disease on some trees. Restriction fragment length polymorphism (RFLP) analyses using four restriction enzymes (HhaI, HpaII, HaeIII and RsaI) and sequence analyses of partial 16S rRNA and rp genes demonstrated that apple phytoplasma isolates in the centre of Iran are related to ‘Ca. Phytoplasma asteris’ and ‘Ca. Phytoplasma aurantifolia’. This is the first report of apples infected with ‘Ca. Phytoplasma asteris’ in Iran and the first record from association of ‘Ca. Phytoplasma aurantifolia’ with apples worldwide.     

Identification and Molecular Characterization of ‘Candidatus Phytoplasma mali’ Isolates in North‐western Italy

Apple proliferation (AP) is an important disease and is prevalent in several European countries. The causal agent of AP is ‘Candidatus Phytoplasma mali’ (‘Ca. Phytoplasma mali’). In this work, isolates of ‘Ca. Phytoplasma mali’ were detected and characterized through polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analyses of 16S rRNA gene and non‐ribosomal DNA fragment. The presence of three AP subtypes (AT‐1, AT‐2 and AP‐15) was identified in 31 symptomatic apple trees and two samples each constituted by a pool of five insects, collected in north‐western Italy, where AT‐1 is a dominant subtype. Subsequent nucleotide sequence analysis of the PCR‐amplified 1.8 kb (P1/P7) fragment, containing the 16S rDNA, the 16S–23S intergenic ribosomal region and the 5′‐end of the 23S rDNA, revealed the presence of at least two phytoplasmal genetic lineages within the AT‐1 subtype, designed AT‐1a and AT‐1b. Moreover, in silico single nucleotide polymorphism (SNP) analysis based on 16S rDNA sequence can differentiate AT‐1 subtype from AT‐2 and AP‐15 subtypes. Our data showed a high degree of genetic diversity among ‘Ca. Phytoplasma mali’ population in north‐western Italy and underlined the possible use of the 16S rDNA analysis for the identification and the geographical origin assignation of isolates of AP phytoplasma. Molecular markers on 16S rDNA, here identified, could be useful for studying the epidemiology of AP disease.     

An ‘ecological trap’ for yellow warbler nest microhabitat selection

Contrary to assumptions of habitat selection theory, field studies frequently detect ‘ecological traps’, where animals prefer habitats conferring lower fitness than available alternatives. Evidence for traps includes cases where birds prefer breeding habitats associated with relatively high nest predation rates despite the importance of nest survival to avian fitness. Because birds select breeding habitat at multiple spatial scales, the processes underlying traps for birds are likely scale‐dependent. We studied a potential ecological trap for a population of yellow warblers Dendroica petechia while paying specific attention to spatial scale. We quantified nest microhabitat preference by comparing nest‐ versus random‐site microhabitat structure and related preferred microhabitat features with nest survival. Over a nine‐year study period and three study sites, we found a consistently negative relationship between preferred microhabitat patches and nest survival rates. Data from experimental nests described a similar relationship, corroborating the apparent positive relationship between preferred microhabitat and nest predation. As do other songbirds, yellow warblers select breeding habitat in at least two steps at two spatial scales; (1) they select territories at a coarser spatial scale and (2) nest microhabitats at a finer scale from within individual territories. By comparing nest versus random sites within territories, we showed that maladaptive nest microhabitat preferences arose during within‐territory nest site selection (step 2). Furthermore, nest predation rates varied at a fine enough scale to provide individual yellow warblers with lower‐predation alternatives to preferred microhabitats. Given these results, tradeoffs between nest survival and other fitness components are unlikely since fitness components other than nest survival are probably more relevant to territory‐scale habitat selection. Instead, exchanges of individuals among populations facing different predation regimes, the recent proliferation of the parasitic brown‐headed cowbird Molothrus ater, and/or anthropogenic changes to riparian vegetation structure are more likely explanations.     

The role of avian ‘seed predators’ as seed dispersers

Seed dispersal is a central process in plant ecology with consequences for species composition and habitat structure. Some bird species are known to disperse the seeds they ingest, whereas others, termed ‘seed predators’, digest them and apparently play no part in dispersal, but it is not clear if these are discrete strategies or simply the ends of a continuum. We assessed dispersal effectiveness by combining analysis of faecal samples and bird density. The droppings of seed dispersers contained more entire seeds than those of typical seed predators, but over a quarter of the droppings of seed predators contained whole seeds. This effect was further magnified when bird density was taken into account, and was driven largely by one frequent interaction: the Chaffinch Fringilla coelebs, a typical seed predator and the most abundant bird species in the area and dispersed seeds of Leycesteria formosa, a non‐native plant with berry‐like fruits. These results suggest the existence of a continuum between seed predators and seed dispersers.     

Cleaner fish, Labroides dimidiatus, diet preferences for different types of mucus and parasitic gnathiid isopods

Cleaner fish, Labroides dimidiatus, prefer the mucus of the parrotfish, Chlorurus sordidus, to parasitic gnathiid isopods, the main items in their diet, indicating a major conflict between clients and cleaners over what the latter should eat during interactions. We tested whether the conflict varied with client species (and the quality of its mucus) and with the presence of blood in the gnathiids. First, we offered cleaners the choice between mucus of the parrotfish and that of the snapper, Lutjanus fulviflamma. When offered equal amounts of mucus on Plexiglas plates, cleaners readily developed a significant preference for the parrotfish mucus. Reducing the amount of parrotfish mucus by 75% made the preference disappear. In a second test, we offered the cleaners gnathiids that were or were not engorged with client fish blood. Cleaners showed no significant preference for either food item. Our results suggest that the degree of conflict between cleaners and clients may vary between species, depending on whether the latter have a preferred mucus. In contrast, the cleaners' lack of preference for engorged gnathiids benefits clients because it means that cleaners do not hesitate to eat unengorged gnathiids before the gnathiids harm the fish by removing blood or by transmitting blood parasites.