Does the presence of grassy strips and landscape grain affect the spatial distribution of aphids and their carabid predators?

• 1 We investigated, over the course of 2 years, the spatial distribution and abundance of two species of aphid, Metopolophium dirhodum and Sitobion avenae, and predatory species of carabid. This was undertaken in 24 wheat fields in ‘coarse‐grain’ and ‘fine‐grain’ landscapes in western France. A greater percentage of the latter landscape was covered by hedgerows and grassland and the total area covered by fields and the average size of the fields were smaller.
• 2 The effects on aphid abundance of the distance from field margins, the presence of grassy strips and carabid abundance were determined in both landscapes.
• 3 Both aphid species were more abundant in the ‘fine‐grain’ landscape, which may have been a result of the higher density of semi‐natural elements. In both types of landscape, the total numbers of aphids were negatively correlated with the distance from the field margin. This may have been because aphids were dispersing from overwintering sites in field margins. The abundance of M. dirhodum was strongly negatively correlated with the presence of grassy strips in the ‘coarse‐grain’ landscape, although there were no such significant correlations for either of the aphid species in the ‘fine‐grain’ landscape.
• 4 Aphid and carabid abundances were negatively correlated in the ‘fine‐grain’ and positively in ‘coarse‐grain’ landscape.
• 5 The results obtained in the present study emphasize the importance of semi‐natural areas in agricultural landscapes in shaping the spatial distribution of aphids and carabid beetles, their natural enemies, at different spatial scales.

     

A smelling trip into the past: the influence of synthetic materials on the history of perfumery

Contemporary perfumery has its roots in the work of the past, and many of the perfumes from this time have long since disappeared. What follows is a short account of some of the most famous perfumes from the past which have been inspired by the novel synthetic materials of the time. These important creations include, ‘Fougère Royale’ by Houbigant (1884) containing coumarin ( 1 ), ‘Jicky’ by Guerlain (1889) containing vanillin ( 2 ) and linalool ( 3 ), ‘Vera Violetta’ by Roger & Gallet (1892) containing α‐ and β‐ionone ( 4 and 5 , resp.), ‘Trèfle Incarnat’ by Piver (1898) containing isoamyl salicylate ( 6 ), ‘La Rose Jacqueminot’ of Coty (1904) containing Rhodinol ( 7 ), ‘Après l'Ondée’ by Guerlain (1906) containing para‐anisaldehyde ( 8 ), ‘Quelques Fleurs’ by Houbigant (1912) containing hydroxycitronellal ( 9 ), ‘N°5’ by Chanel (1921) containing the aldehydes C‐10 ( 10 ), C‐110 ( 11 ), and C‐12 ( 12 ), ‘Nuit De Noël’ by Caron (1922) containing 6‐isobutylquinoline ( 14 ), and ‘Femme’ by Rochas (1944) containing the so‐called ‘aldehyde C‐14’ ( 15 , γ‐undecalactone). The Osmotheque, the International Conservatory of Perfumes, was launched in 1990 and is regarded as a primary source of knowledge for the history of perfumery. Its vocation is to compile an amazing collection of 1700 perfumes (400 of them almost forgotten fragrances) – jewels of perfumery.     

Biochemical and epigenetic changes in phytoplasma‐recovered periwinkle after indole‐3‐butyric acid treatment

Aim: To elucidate the possible mechanism of phytoplasma elimination from periwinkle shoots caused by indole‐3‐butyric acid (IBA) treatment. Methods and Results: It has been shown that a transfer of in vitro‐grown phytoplasma‐infected Catharanthus roseus (periwinkle) plantlets from medium supplemented with 6‐benzylaminopurine (BA) to one supplemented with IBA can induce remission of symptoms and even permanent elimination of ‘Candidatus Phytoplasma asteris’ reference strain HYDB. Endogenous auxin levels and general methylation levels in noninfected periwinkles, periwinkles infected with two ‘Candidatus Phytoplasma’ species and phytoplasma‐recovered periwinkles were measured and compared. After the transfer from cytokinin‐ to auxin‐containing media, healthy shoots maintained their phenotype, methylation levels and hormone concentrations. Phytoplasma infection caused a change in the endogenous indole‐3‐acetic acid to IBA ratio in periwinkle shoots infected with two ‘Candidatus Phytoplasma’ species, but general methylation was significantly changed only in shoots infected with ‘Ca. P. asteris’, which resulted in the only phytoplasma species eliminated from shoots after transfer to IBA‐containing medium. Both phytoplasma infection and treatment with plant growth regulators influenced callose deposition in phloem tissue, concentrations of photosynthetic pigments and soluble proteins, H₂O₂ levels and activities of catalase (CAT) and ascorbate peroxidase (APX). Conclusion: Lower level of host genome methylation in ‘Ca. P. asteris’‐infected periwinkles on medium supplemented with BA was significantly elevated after IBA treatment, while IBA treatment had no effect on cytosine methylation in periwinkles infected with ‘Candidatus Phytoplasma ulmi’ strain EY‐C. Significance and Impact of the Study: Hormone‐dependent recovery is a distinct phenomenon from natural recovery. As opposed to spontaneously recovered plants in which elevated peroxide levels and differential expression of peroxide‐related enzymes were observed, in hormone‐dependent recovery changes in global host genome, methylation coincide with the presence/absence of phytoplasma.     

Early post‐fire succession in northwestern Patagonia grasslands

Abstract. Large‐scale disturbances, notably fire and grazing, structure grass and shrubland dynamics in semi‐arid environments. We studied early post‐fire succession in two burned grasslands, one unburned grassland, and one shrubland near the burned area. We observed three processes: (1) establishment of a ‘phantom’ community comprised of fugitive species. Although transient, these species increase diversity and recharge the seed bank before the next disturbance; (2) regeneration of the original community by persistence of resprouter species and by auto‐replacement; (3) early stages of invasion by seedlings of the shrub Fabiana imbricata, which germinate next to shrubland and create new F. imbricata patches. Weed invasion was principally due to the ruderal exotic species Verbascum thapsus from the nearby road verge and by rapid increase of Rumex acetosella cover, another exotic species present before the fire. Although post‐fire climatic conditions are particularly important in semi‐arid environments, succession depends greatly on the regeneration strategies and dispersal abilities of the species present in the burned area. The phantom community occurs only at the first stage of succession when there is little competition for resources. We could call this process ‘the race for occupation of the area’. The second stage, when competition for resources becomes progressively more important, could be called ‘the effort to maintain space’.     

Grapevine Viruses' Detection and Sanitary Selection in Grapevine Germplasm of Calabria (Southern Italy)

A survey of grapevine viruses present in the region of Calabria (southern Italy) was carried out, and the sanitary selection was conducted on various indigenous varieties. Serological (ELISA) and molecular (multiplex RT‐PCR) tests were used to detect the viruses included in the Italian certification programme: Arabis mosaic virus (ArMV), Grapevine fanleaf virus (GFLV), Grapevine leafroll associated virus 1 (GLRaV‐1), Grapevine leafroll associated virus 2 (GLRaV‐2), Grapevine leafroll associated virus 3 (GLRaV‐3), Grapevine virus A (GVA), Grapevine virus B (GVB) and Grapevine fleck virus (GFkV). The frequency with which the above viruses have been detected was 37.4, 32.6, 12.8, 7.7, 7.3, 1.9 and 0.3%, respectively, for GVA, GLRaV‐3, GFLV, GFKV, GLRaV‐1, GLRaV‐2 and GVB. ArMV was never found. The sanitary selection allowed for the detection of 6 putative clones of ‘Arvino’, 2 of ‘Magliocco dolce’ and 2 of the rootstock ‘17–37’ free of the above‐mentioned viruses. The necessary process for the commercialization of these clones as ‘certified’ propagation material was accomplished, and their official approval by the Italian Ministry of Agriculture is currently in progress.     

Control of aphid-vectored and thrips-borne virus spread in lily, tulip, iris and dahlia by sprays of mineral oil, polydimethylsiloxane and pyrethroid insecticide in the field

In this study control of spread by insect vectors of non‐persistent Lily symptomless virus and Lily mottle virus in lily, Tulip breaking virus in tulip, Iris mild mosaic virus, Narcissus latent virus and Iris severe mosaic virus in bulbous iris, and semi‐persistent Dahlia mosaic virus and persistent Tomato spotted wilt virus in dahlia has been evaluated with weekly sprays of mineral oil, beta‐pinene emulsion, polydimethylsiloxane emulsions and pyrethroid insecticide. In lily, beta‐pinene in ‘Wilt Prufgave’ 40% reduction of virus spread. In 1995–97 deltamethrin in ‘Decisgave’ 22–58% reduction. Deltamethrin added to sprays of mineral oil ‘Luxan oil H’ and polydimethylsiloxane (PDMS), e.g. in ‘Dow Corning 36’, efficiently improved control efficacy. The latter was also observed in tulip and dahlia. Mineral oil and deltamethrin gave best control by 81–97% reduction of virus spread at standard spray volumes (6.25 litre ha^?1+0.4 litre ha¹). ‘Luxan oil H’ at 3.125 litre ha^?1 with deltamethrin gave 69–91% control. Efficacy of control by polydimethylsiloxane in ‘Dow Corning 36’ was superior to ‘Luxan anti‐foam’. ‘Dow Corning 36’ with deltamethrin (7+0.4 litre ha^?1) gave satisfactory control (68–87%). In tulip, the control by ‘Dow Corning 36’/deltamethrin sprays proved satisfactory compared with ‘Luxan oil H’/‘Decis’‐sprays. In bulbous iris the efficacy of tested PDMS‐brands was clearly different in favour of ‘Dow Corning 36’. In dahlia mineral‐oil and PDMS‐sprays gave some control of semi‐persistent DaMV (16–24%). This ranged at higher level (65–80%) when deltamethrin was added to the spray mixture. Similar trends were observed in the control of persistent TSWV. The effect of polydimethylsiloxane emulsions in the spectrum of virus‐control agents is described for the first time. The effect of PDMS compared with that of mineral oils and synthetic pyrethroid insecticides is discussed with respect to efficacy, mode of action to prevent virus transmission and possible reduction of bulb weights in vegetatively propagated bulb crops.     

Band‐aids for Buchnera and B vitamins for all

Evolution lacks foresight, and hence, key adaptations may produce major challenges over the long run. The natural world is rife with examples of long‐term ‘side effects’ associated with quick‐fix tinkering, including blind spots in vertebrate eyes. An important question is how nature compensates for imperfections once evolution has set a course. The symbioses associated with sap‐feeding insects present a fascinating opportunity to address this issue. On one hand, the substantial diversity and biomass of sap‐feeding insects are largely due to ancient acquisitions of nutrient‐provisioning bacterial symbionts. Yet, the insularity and small population sizes enforced by intracellular life and strict maternal transfer inevitably result in the degradation of symbiont genomes and, often, the beneficial services that symbionts provide. Stabilization through lateral transfer of bacterial genes into the host nucleus (often from exogenous sources) or replacement of the long‐standing symbiont with a new partner are potential solutions to this evolutionary dilemma (Bennett & Moran 2015 ). A third solution is adoption of a cosymbiont that compensates for specific losses in the original resident. Ancient ‘co‐obligate’ symbiont pairs in mealybugs, leafhoppers, cicadas and spittlebugs show colocalization, codiversification, metabolite exchange and generally nonredundant nutrient biosynthesis (Bennett & Moran 2015 ). But in this issue, Meseguer et al. ( 2017 ) report on a different flavour of cosymbiosis among conifer‐feeding Cinara aphids.     

Total Synthesis of the Peptaibols Hypomurocin A3 and Hypomurocin A5, and Their Conformation Analysis

The total syntheses of hypomurocin A3 and hypomuricin A5 (HM A3 and HM A5, resp.) in solution phase are described. These syntheses have been successfully achieved by applying the ‘azirine/oxazolone method’ to introduce the two Aib‐Pro units into the backbone of these undecapeptaibols in one step with methyl 2,2‐dimethyl‐2H‐azirine‐3‐prolinate as the ‘Aib‐Pro synthon’. The coupling of Z‐protected (Z=(benzyloxy)carbonyl) amino acids or peptide acids with amino acid tert‐butyl esters and of peptide segments was carried out according to the TBTU (=O‐(benzotriazol‐1‐yl)‐N,N,N′,N′‐tetramethyluronium tetrafluoroborate) and HOBt (=1‐hydroxybenzotriazole) protocol. Purification by reversed‐phase HPLC gave the peptides in pure form. The products were characterized by optical rotation, NMR and IR spectroscopy, mass spectrometry, and elemental analysis. The crystal structures of HM A3 and of an octapeptide fragment of HM A5 could be obtained. An NMR analysis was also carried out with HM A3 and HM A5 to determine their conformations in solution. A global structural comparison between the three sequences of HM A1, HM A3, and HM A5 was performed, as well as the HPLC correlation of the natural HM A family and the synthetic samples.     

Risk screening of non‐native freshwater fishes at the frontier between Asia and Europe: first application in Turkey of the fish invasiveness screening kit

The aim of the present study was to assess the invasive potential of introduced non‐native and translocated fishes in Turkey (Anatolia and Thrace) by applying the Fish Invasiveness Screening Kit (FISK), a risk identification tool for freshwater fishes. From independent evaluations by two assessors of 35 species, calibration of FISK for Turkey identified a threshold score of 23, which reliably distinguished between potentially invasive (high risk) and potentially non‐invasive (medium to low risk) fishes for Anatolia (Asia) and Thrace (Europe). No species was categorized as ‘low risk’, 18 species were categorized as ‘medium risk’ and 17 as ‘high risk’ (two being ‘moderately high risk’, nine ‘high risk’, and six ‘very high risk’). The highest scoring species was gibel carp Carassius gibelio, whereas the lowest scoring species was Caucasian dwarf goby Knipowitschia caucasica, a translocated species. Assessor certainty in their responses averaged overall between ‘mostly uncertain’ and ‘mostly certain’, with red piranha Pygocentrus nattereri and topmouth gudgeon Pseudorasbora parva achieving the lowest and highest certainty values, respectively, and with overall significant differences in certainty between assessors. The results of the present study indicate that FISK is a useful and viable tool for identifying potentially invasive non‐native fishes in Turkey, a country characterized by natural biogeographical frontiers.     

Divergent pheromone-mediated insect behaviour under global atmospheric change

While the effects of global atmospheric changes on vegetation and resulting insect populations(‘bottom‐up interactions’) are being increasingly studied, how these gases modify interactions among insects and their natural enemies (‘top‐down interactions’) is less clear. As natural enemy efficacy is governed largely by behavioural mechanisms, altered prey finding and prey defence may change insect population dynamics. Here we show that pheromone‐mediated escape behaviours, and hence the vulnerability of insects to natural enemies, are divergent under atmospheric conditions associated with global climate change. Chaitophorus stevensis, a common aphid on trembling aspen trees, Populus tremuloides, have diminished escape responses in enriched carbon dioxide (CO₂) environments, while those in enriched ozone (O₃) have augmented escape responses, to alarm pheromone. These results suggest that divergent pheromone‐mediated behaviours could alter predator–prey interactions in future environments.     

Spatial and temporal diversity in hyperparasitoid communities of Cotesia glomerata on garlic mustard,Alliaria petiolata

1. Interactions between two trophic levels can be very intimate, often making species dependent on each other, something that increases with specialisation. Some specialised multivoltine herbivores may depend on multiple plant species for their survival over the course of a growing season, especially if their food plants are short‐lived and grow at different times. Later generations may exploit different plant species from those exploited by previous generations. 2. Multivoltine parasitoids as well as their natural enemies must also find their hosts on different food plants in different habitats across the season. Secondary hyperparasitoid communities have been studied on cocoons of the primary parasitoid, Cotesia glomerata (Hymenoptera: Braconidae), on black mustard (Brassica nigra) – a major food plant of its host, the large cabbage white (Pieris brassicae) – which grows in mid‐summer. 3. Here, hyperparasitoid communities on C. glomerata pupal clusters were studied on an early‐season host, garlic mustard, Alliaria petiolata, over ‘time’ (one season, April–July) in six closely located ‘populations’ (c. 2 km apart), and within two different ‘areas’ at greater separation (c. 100 km apart). At the plant level, spatial effects of pupal ‘location’ (canopy or bottom) on the plant were tested. 4. Although large‐scale separation (area) did not influence hyperparasitism, sampling time and small‐scale separation (population) affected hyperparasitism levels and composition of hyperparasitoid communities. Location on the plant strongly increased proportions of winged species in the canopy and proportions of wingless species in bottom‐located pupae. 5. These results show that hyperparasitism varies considerably at the local level, but that differences in hyperparasitoid communities do not increase with spatial distance.     

Inheritance of vector competence by the thrips Ceratothripoides claratris (Shumsher) (Thysanoptera: Thripidae)

The thrips Ceratothripoides claratris is an efficient vector of the Capsicum chlorosis virus (CaCV). Transmission studies with a natural population of C. claratris found in a greenhouse ‘GH’ and a ‘colony’ derived from this ‘GH’ population by selection and inbreeding resulted in lowering the percentage of viruliferous individuals within the ‘colony’. After passing through approximately 20 generations, the ‘colony’ lost the ability to transmit the CaCV. When either viruliferous or non‐viruliferous virgin females reproduced parthenogenetically, 81% of F1 arrhenotokous males inherited their viruliferous status from their mothers, whilst, no viruliferous offspring arose from non‐viruliferous virgin mothers. Crosses between viruliferous and non‐viruliferous individuals suggest that the competence of the thrips C. claratris as a vector for this virus is probably a heritable trait controlled by a recessive allele.     

More on the genetical theory of multilevel selection

In my article The genetical theory of multilevel selection, I provided a synthesis of the theory of multilevel selection (MLS) and the theory of natural selection in class‐structured populations. I framed this synthesis within Fisher's genetical paradigm, taking a strictly genetical approach to traits and fitness. I showed that this resolves a number of long‐standing conceptual problems that have plagued the MLS literature, including the issues of ‘aggregate’ vs. ‘emergent’ group traits, ‘collective fitness₁’ vs. ‘collective fitness₂’ and ‘MLS1’ vs. ‘MLS2 ‘. In his commentary, Goodnight suggests this theoretical and conceptual synthesis is flawed in several respects. Here, I show this is incorrect, by: reiterating the theoretical and conceptual goals of my synthesis; clarifying that my genetical approach to traits is necessary for a proper analysis of the action of MLS independently of non‐Darwinian factors; emphasizing that the Price–Hamilton approach to MLS provides a consistent, useful and conceptually superior theoretical framework; and explaining the role of reproductive value in the study of natural selection in class‐structured populations. I also show that Goodnight's contextual analysis treatment of MLS in a class‐structured population is mathematically, biologically and conceptually inadequate.     

Diffusion limitations and metabolic factors associated with inhibition and recovery of photosynthesis from drought stress in a C3 perennial grass species

Stomatal closure and metabolic impairment under drought stress limits photosynthesis. The objective of this study was to determine major stomatal and metabolic factors involved in photosynthetic responses to drought and recovery upon re‐watering in a C₃ perennial grass species, Kentucky bluegrass (Poa pratensis L.). Two genotypes differing in drought resistance, ‘Midnight’ (tolerant) and ‘Brilliant’ (sensitive), were subjected to drought stress for 15 days and then re‐watered for 10 days in growth chambers. Single‐leaf net photosynthetic rate (A), stomatal conductance (g_s) and transpiration rate (Tr) decreased during drought, with a less rapid decline in ‘Midnight’ than in ‘Brilliant’. Photochemical efficiency, Rubisco activity and activation state declined during drought, but were significantly higher in ‘Midnight’ than in ‘Brilliant’. The relationship between A and internal leaf CO₂ concentration (A/Ci curve) during drought and re‐watering was analyzed to estimate the relative influence of stomatal and non‐stomatal components on photosynthesis. Stomatal limitation (Ls %), non‐stomatal limitation (Lns %), CO₂ compensation point (CP) and dark respiration (Rd) increased with stress duration in both genotypes, but to a lesser extent in ‘Midnight’. Maximum CO₂ assimilation rate (A_max), carboxylation efficiency (CE) and mesophyll conductance (g_m) declined, but ‘Midnight’ had significantly higher levels of A_max, CE and g_m than ‘Brilliant’. Maximum carboxylation rate of Rubisco (V_cmax) and ribulose‐1,5‐bisphospate (RuBP) regeneration capacity mediated by maximum electron transport rate (J_max) decreased from moderate to severe drought stress in both genotypes, but to a greater extent in ‘Brilliant’ than in ‘Midnight’. After re‐watering, RWC restored to about 90% of the control levels in both genotypes, whereas A, g_s, Tr and Fv/Fm was only partially recovered, with a higher recovery level in ‘Midnight’ than in ‘Brilliant’. Rubisco activity and activation state restored to the control level after re‐watering, with more rapid increase in ‘Midnight’ than in ‘Brilliant’. The values of Ls, Lns, CP and Rd declined, and A_max, CE, V_cmax, J_max and g_m increased after re‐watering, with more rapid change in all parameters in ‘Midnight’ than in ‘Brilliant’. These results indicated that the maintenance of higher A and A_max under drought stress in drought‐tolerant Kentucky bluegrass could be attributed to higher Rubico activation state, higher CE and less stomatal limitation. The ability to resume metabolic activity (A_max, CE, Fv/Fm and Rubisco) was observed in the drought‐tolerant genotype and is the most likely cause for the increased recuperative ability of photosynthesis. Incomplete recovery of photosynthesis upon re‐watering could be attributable to lasting stomatal limitations caused by severe drought damage in both genotypes. Promoting rapid stomatal recovery from drought stress may be critical for plants to resume full photosynthetic capacity in C₃ perennial grass species.     

A new approach for mealybug management: recruiting an indigenous,but ‘non‐natural’ enemy for biological control using an attractant

We previously discovered that (2,4,4‐trimethyl‐2‐cyclohexenyl)‐methyl butyrate (cyclolavandulyl butyrate, CLB) is an attractant for the mealybug‐parasitic wasp Anagyrus sawadai Ishii (Hymenoptera: Encyrtidae: Anagyrini). This wasp is not likely to parasitize the Japanese mealybug, Planococcus kraunhiae (Kuwana) (Hemiptera: Pseudococcidae), under natural conditions. In this study, we showed that this ‘non‐natural’ enemy wasp can parasitize P. kraunhiae in the presence of CLB in field experiments. Laboratory‐reared mealybugs placed on persimmon trees with CLB‐impregnated rubber septa were parasitized significantly more often by endoparasitic wasps than those on non‐treatment trees (18.1–40.3 vs. 0–6.3%). Anagyrus sawadai accounted for 20% of the wasps that emerged from mealybugs placed on CLB‐treated trees. Moreover, CLB attracted another minor parasitoid, Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae: Anagyrini), which also parasitized more P. kraunhiae in the presence of CLB. All wasps that emerged from the mealybugs on control trees were Anagyrus fujikona Tachikawa, a major parasitoid of P. kraunhiae around the test location. These results demonstrated that CLB can recruit an indigenous, but ‘non‐natural’ enemy that does not typically attack P. kraunhiae under natural conditions, as well as a minor natural enemy, for biological control of this mealybug species.     

The high‐quality genome of Brassica napus cultivar ‘ZS11’ reveals the introgression history in semi‐winter morphotype

Allotetraploid oilseed rape (Brassica napus L.) is an agriculturally important crop. Cultivation and breeding of B. napus by humans has resulted in numerous genetically diverse morphotypes with optimized agronomic traits and ecophysiological adaptation. To further understand the genetic basis of diversification and adaptation, we report a draft genome of an Asian semi‐winter oilseed rape cultivar ‘ZS11’ and its comprehensive genomic comparison with the genomes of the winter‐type cultivar ‘Darmor‐bzh’ as well as two progenitors. The integrated BAC‐to‐BAC and whole‐genome shotgun sequencing strategies were effective in the assembly of repetitive regions (especially young long terminal repeats) and resulted in a high‐quality genome assembly of B. napus ‘ZS11’. Within a short evolutionary period (~6700 years ago), semi‐winter‐type ‘ZS11’ and the winter‐type ‘Darmor‐bzh’ maintained highly genomic collinearity. Even so, certain genetic differences were also detected in two morphotypes. Relative to ‘Darmor‐bzh’, both two subgenomes of ‘ZS11’ are closely related to its progenitors, and the ‘ZS11’ genome harbored several specific segmental homoeologous exchanges (HEs). Furthermore, the semi‐winter‐type ‘ZS11’ underwent potential genomic introgressions with B. rapa (A_r). Some of these genetic differences were associated with key agronomic traits. A key gene of A03.FLC3 regulating vernalization‐responsive flowering time in ‘ZS11’ was first experienced HE, and then underwent genomic introgression event with A_r, which potentially has led to genetic differences in controlling vernalization in the semi‐winter types. Our observations improved our understanding of the genetic diversity of different B. napus morphotypes and the cultivation history of semi‐winter oilseed rape in Asia.     

Dispersal behaviour of individuals in metapopulations of two British butterflies

Dispersal patterns are important in metapopulation ecology because they affect the dynamics and survival of populations. However, because little empirical information exists on dispersal behaviour of individuals, theoretical models usually assume random dispersal. Recent empirical evidence, by contrast, suggests that the butterfly Maniola jurtina uses a non‐random, systematic dispersal strategy, can detect and orient towards habitat from distances of 100–150 m, and prefers a familiar habitat patch over a non‐familiar one (‘homing behaviour’). The present study (1) investigated whether these results generalise to another butterfly species, Pyronia tithonus; and (2) examined the cause of the observed ‘homing behaviour’ in M. jurtina. P. tithonus used a similar non‐random, systematic dispersal strategy to M. jurtina, had a similar perceptual range for habitat detection and preferred a familiar habitat patch over a non‐familiar one. The ‘homing behaviour’ of M. jurtina was found to be context‐dependent: individual M. jurtina translocated within habitat did not return towards their capture point, whereas individuals translocated similar distances out of habitat did return to their ‘home’ patch. We conclude that butterfly ‘homing behaviour’ is not based on an inherent preference for a familiar location, but that familiarity with an area facilitates the recognition of suitable habitat, towards which individuals orient if they find themselves in unsuitable habitat. Contrary to conventional wisdom, we suggest that frequent, short ‘excursions’ over habitat patch boundaries are evolutionarily advantageous to individuals, because increased familiarity with the surrounding environment is likely to increase the ability of a straying animal to return to its natural habitat, and to reduce the rate of mortality experienced by individuals attempting to disperse between habitat patches. We discuss the implications of the non‐random dispersal for existing metapopulation models, including models of the evolution of dispersal rates.     

CRISPR/Cas9‐mediated targeted mutagenesis of GmFT2a delays flowering time in soya bean

Flowering is an indication of the transition from vegetative growth to reproductive growth and has considerable effects on the life cycle of soya bean (Glycine max). In this study, we employed the CRISPR/Cas9 system to specifically induce targeted mutagenesis of GmFT2a, an integrator in the photoperiod flowering pathway in soya bean. The soya bean cultivar Jack was transformed with three sgRNA/Cas9 vectors targeting different sites of endogenous GmFT2a via Agrobacterium tumefaciens‐mediated transformation. Site‐directed mutations were observed at all targeted sites by DNA sequencing analysis. T1‐generation soya bean plants homozygous for null alleles of GmFT2a frameshift mutated by a 1‐bp insertion or short deletion exhibited late flowering under natural conditions (summer) in Beijing, China (N39°58′, E116°20′). We also found that the targeted mutagenesis was stably heritable in the following T2 generation, and the homozygous GmFT2a mutants exhibited late flowering under both long‐day and short‐day conditions. We identified some ‘transgene‐clean’ soya bean plants that were homozygous for null alleles of endogenous GmFT2a and without any transgenic element from the T1 and T2 generations. These ‘transgene‐clean’ mutants of GmFT2a may provide materials for more in‐depth research of GmFT2a functions and the molecular mechanism of photoperiod responses in soya bean. They will also contribute to soya bean breeding and regional introduction.     

Ecological speciation without host plant specialization; possible origins of a recently described cryptic Papilio species

North American Papilio canadensis and P. glaucus (Lepidoptera: Papilionidae, these Papilio = Pterourus) have previously been described as having allopatric distributions separated by a narrow hybrid zone running from Minnesota to southern New England, and southward in the Appalachian Mountains (possibly to northern Georgia). Recent patterns of hybridization and introgression suggest a more complex interaction between the two, possibly even resulting in the formation of a new species (Pterourus appalachiensis Pavulaan & Wright, 2002). Recently, extensive northward interspecific introgression of P. glaucus‐diagnostic traits has been observed in the hybrid zone. These include wing bands and other color patterns, the ability to feed on tulip tree leaves, and Hk‐100 allozymes; all are autosomally encoded. However, there has been little northward introgression of certain other P. glaucus traits (such as facultative diapause and bivoltinism, and Ldh‐100 allozymes, both X‐linked; and the Y‐linked melanic mimicry gene in females). Interspecific recombination of the X‐chromosome has evidently occurred, as shown by discordant patterns of X‐linked markers. The P. glaucus X‐linked Pgd‐100 and Pgd‐50 alleles have introgressed 200–400 km north of the historical hybrid zone, yet the P. glaucus X‐linked Ldh‐100 allele has not. The allele frequency shift for both genes is more closely related to the ‘thermal landscape’ (i.e., accumulated degree‐days above a developmental base threshold of 50 °F (=10 °C)) than to latitude. Delayed post‐diapause eclosion of cohorts within the hybrid zone, e.g., the New York/Vermont border area, has produced a natural ‘false‐second generation’ flight (a hybrid swarm of synchronous males and females, where 2300–2700 °F degree‐days have accumulated each year since 1998) that is reproductively isolated from flights of both parental species. Moreover, the newly described P. appalachiensis exhibits a unique combination of traits. These include obligate diapause, a univoltine habit, and the Ldh‐80 or Ldh‐40 alleles (as for P. canadensis), the Pgd‐100 or Pgd‐50 alleles (as for P. glaucus), and a delayed ‘false‐second generation’ reproductive flight period (as observed in the hybrid zone). Since 2001, a rare allele or ‘hybrizyme’ (Ldh‐20) has appeared in this false second generation at high frequencies (40–50%). We hypothesize that strong selection against the facultative diapause (od‐)trait (and the linked Ldh‐100 allele) in regions with 2800 °F degree‐days or less, and divergent selection in favor of Pgd‐100 (or a closely linked trait) combined with allochronic reproductive isolation, has resulted in recombinational, parapatric, hybrid speciation. There is no evidence at present that host‐plant shifts or changes in sex pheromones have driven this process, in contrast to many other speciation events in the Lepidoptera.