Conodonts of the genus Lochriea in Ireland and the recognition of the Viséan–Serpukhovian (Carboniferous) boundary

Conodonts of the genus Lochriea offer high‐resolution biostratigraphical differentiation of the upper Mississippian (Carboniferous). In particular, L. ziegleri is regarded as the most suitable index taxon for recognition of a revised Viséan–Serpukhovian boundary and selection of a Global Stratotype Section and Point. Mixed carbonate‐siliciclastic Carboniferous sections from western Ireland demonstrate that gradual morphological evolution is expressed within the Lochriea lineage, evidenced by P₁‐elements with progressively more complex ornament appearing in a pulsed fashion in the Late Viséan. Significant diversification of the Lochriea conodonts occurs below the currently recognized base of the Namurian (identified by ammonoids), with which the basal Serpukhovian has been correlated in the past. The First Appearance Datum (FAD) of L. ziegleri in the Lugasnaghta Section of western Ireland is apparently coincident with the FAD's of other complexly ornamented Lochriea species (e.g. L. cruciformis) and corresponds with the Irish and British P_2a ammonoid biozone and the lower part of the upper Cf6δ (MFZ15) foraminiferal biozone. The FAD of L. ziegleri in Ireland is closely related to other Lochriea morphotypes with complex ornament, which are difficult to identify to species level using current species definitions. These forms, recorded from the three sections examined (St Brendan's Well, Kilnamona and Lugasnaghta), may partly be explained as abnormal growth histories, evolutionary intermediate forms, etc. In some instances, however, the apparently consistent and novel morphotypes suggest that current Lochriea taxonomy needs to be re‐examined. Furthermore, given the close association of the morphologies with asymmetric complex ornament and L. ziegleri, these taxa may hold significance as biostratigraphical tools in their own right.     

The Carboniferous carbonates of the Dombar Hills (western Kazakhstan) and the problem of the Viséan–Serpukhovian boundary

The Upper Viséan–Serpukhovian ammonoid-rich carbonates in the Dombar Hills (Aktobe Region, western Kazakhstan) provide an excellent opportunity to calibrate the ammonoid and conodont zonations around the base of the Serpukhovian Stage, and are important for interregional correlation. A section in the Dombar Hills spanning the Viséan–Serpukhovian boundary is measured and its fossil content is analyzed. Two ammonoid genozones (Hypergoniatites-Ferganoceras and Uralopronorites-Cravenoceras) and two conodont zones (Lochriea nodosa and Lochriea ziegleri) are recognized. The section displays a contact between the Hypergoniatites-Ferganoceras and Uralopronorites-Cravenoceras ammonoid genozones in a continuous succession and an evolutionarily early appearance of the genus Cravenoceras. The base of the Serpukhovian Stage is drawn at the level of the first appearance datum (FAD) of the conodont Lochriea ziegleri, which, as in the Verkhnyaya Kardailovka section (potential GSSP candidate, South Urals, Russia) enters within the Hypergoniatites-Ferganoceras ammonoid Genozone.     

Exotic ladybirds for biological control of herbivorous insects – a review

Since the late 19th century, exotic ladybirds (Coleoptera: Coccinellidae) have been used extensively for suppressing herbivorous insects of economic importance. In recent decades, the introduction of non‐native biological control (BC) agents has been greatly limited due to the awareness of the potential non‐target effects of introductions. Nonetheless, recent episodes of biological invasions of economically important pests have raised the need to carefully consider whether the expected benefits of pest control go beyond the possible environmental risks of introduction. To better understand the factors that contributed to successful BC programs, here we review the literature behind classical and augmentative BC using exotic ladybirds. Additionally, by means of case studies, we discuss the BC efficacy of selected exotic species, e.g., Coccinella septempunctata L., Harmonia axyridis (Pallas), and Hippodamia variegata (Goeze), and their position within the communities of predators in the introduced areas of USA, Canada, and Chile. In Europe, much of the research on exotic ladybirds has been conducted on the undesired impact of H. axyridis. Therefore, we summarize the risk assessment data for this species and review the field research investigating the ecological impact on European aphidophagous predators. According to the BIOCAT database of classical BC programs, 212 ladybird species belonging to 68 genera have been released in about 130 years of BC activity, with 14.6% of introductions having resulted in partial, substantial, or complete control of the target pest. However, because post‐release evaluation of establishment and BC success has not always been conducted, this rate could underestimate the successful cases. Among other factors, ladybird establishment and pest suppression mostly depend on (1) intrinsic factors, i.e., high voracity, synchronized predator‐prey life cycle, and high dispersal ability, and (2) extrinsic factors, i.e., adaptability to the new environment and landscape composition. This review contributes to improved understanding of ladybirds as exotic BC agents.     

The Pignola‐Abriola section (southern Apennines,Italy): a new GSSP candidate for the base of the Rhaetian Stage

The base of the Rhaetian stage (Norian/Rhaetian boundary, NRB) is still awaiting formal designation by the International Commission on Stratigraphy. At present, only the 4.30‐m‐thick Steinbergkogel section (Austria) has been proposed as GSSP (Global Stratotype Section and Point) candidate for the base of the Rhaetian. Here we present data from the 63‐m‐thick Pignola‐Abriola section (Southern Apennines, Italy) that we consider an alternative candidate for the Rhaetian GSSP. The Pignola‐Abriola basinal section, represented by hemipelagic–pelagic carbonate successions belonging to the Lagonegro Basin, matches all the requirements for a GSSP: 1, it is well exposed with minimal structural deformation; 2, it is rich in age diagnostic fossils (e.g. conodonts and radiolarians); 3, it yields a geochemical record suitable for correlation (e.g. δ¹³C_org/carb); and 4, it has a robust magnetostratigraphy and is correlated with the Newark APTS for age approximation of the NRB and additional Rhaetian bioevents. In the Pignola‐Abriola section, we opt to place the NRB at the 44.4 metre level, coincident with a prominent negative shift of ca. 6‰ of the δ¹³C_org. This level is located 50 cm below the FAD of conodont Misikella posthernsteini s.s within the radiolarian Proparvicingula moniliformis Zone. Both the negative δ¹³C_org shift and the FAD of Misikella posthernsteini occur within Pignola‐Abriola magnetozone MPA‐5r, at ~205.7 Ma, according to magnetostratigraphical correlation to the Newark APTS. We also illustrate the coeval Mt. Volturino stratigraphical section deposited below the calcite compensation depth (CCD) within the same Lagonegro Basin and characterized by a detailed radiolarian biostratigraphy and strong δ¹³C_org negative shift around the NRB.     

Effects of biodiversity in agricultural landscapes on the protective microbiome of insects – a review

Symbiotic bacteria in herbivorous insects can have strong beneficial impacts on their host's survival, including conferring resistance to natural enemies such as parasitoid wasps or pathogens, while also imposing energetic costs on the host, resulting in cost‐benefit trade‐offs. Whether these trade‐offs favour the hosting of symbionts depends on the growth environment of the herbivore. Long‐term experimental grassland studies have shown that increasing plant species richness leads to an increased diversity of associated herbivores and their natural enemies. Such a change in natural enemy diversity, related to changes in plant diversity, could also drive changes in the community of symbionts hosted by the herbivorous insects. Aphids are one model system for studying symbionts in insects, and effects of host‐plant species and diversity on aphid‐symbiont interactions have been documented. Yet, we still understand little of the mechanisms underlying such effects. We review the current state of knowledge of how biodiversity can impact aphid‐symbiont communities and the underlying drivers. Then, we discuss this in the framework of sustainable agriculture, where increased plant biodiversity, in the form of wildflower strips, is used to recruit natural enemies to crop fields for their pest control services. Although aphid symbionts have the potential to reduce biological control effectiveness through conferring protection for the host insect, we discuss how increasing plant and natural enemy biodiversity can mitigate these effects and identify future research opportunities. Understanding how to promote beneficial interactions in ecological systems can help in the development of more sustainable agricultural management strategies.     

Mutant Alleles at the Brown Locus Encoding Tyrosinase‐Related Protein‐1 (TRP‐1) Affect Proliferation of Mouse Melanocytes in Culture *

Tyrosinase related protein‐1 (TRP‐1) is a melanocyte‐specific gene product involved in eumelanin synthesis. Mutation in the Tyrp1 gene is associated with brown pelage in mouse and oculocutaneous albinism Type 3 in humans (OCA3). It has been demonstrated that TRP‐1 expresses DHICA oxidase activity in the murine system. However, its actual function in the human system is still unclear. The study was designed to determine the effects of mutation at two Typr1 alleles, namely the Tyrp1^b (brown) and Tyrp1^b‐cj (cordovan) compared with wild type Tyrp1^B (black) on melanocyte function and melanin biosynthesis. The most significant finding was that both of the Tyrp1 mutations (i.e. brown expressing a point mutation and cordovan expressing decreased amount of TRP‐1 protein) resulted in attenuation of cell proliferation rates. Neither necrosis nor apoptosis was responsible for the observed decrease in cell proliferation rates of the brown and cordovan melanocytes. Ultrastructural evaluation by electron microscopic analysis revealed that both mutations in Tyrp1 affected melanosome maturation without affecting its structure. These observations demonstrate that mutation in Tyrp1 compromised tyrosinase activity within the organelle. DOPA histochemistry revealed differences in melanosomal stages between black and brown melanocytes but not between black and cordovan melanocytes. There were no significant differences in tyrosine hydroxylase activities of tyrosinase and TRP‐1 in wild type black, brown and cordovan melanocyte cell lysates. We conclude that mutations in Tyrp1 compromise cell proliferation and melanosomal maturation in mouse melanocyte cultures.     

Natural assemblages of Hindeodus conodonts from a Permian–Triassic boundary sequence,Japan

Hindeodus parvus and Hindeodus typicalis occur in a deep‐water chert and claystone section in the Mino Terrane, Japan, which has been identified as a Jurassic accretionary complex. Conodont fossils are preserved as natural assemblages of impression fossils on bedding planes in claystone. In this study, 13 assemblages of Hindeodus species were recognized, comprising at most 13 elements which generally maintain the original composition and structure of an apparatus. We discriminated pairs of carminiscaphate P₁, angulate P₂ and makellate M elements, as well as a single alate S₀ element and two digyrate and four bipennate elements constituting the S array. Although the digyrate and bipennate elements are preserved in the S₂ and S_3–4 positions, respectively, a pair of S₁ elements was not found due to incompleteness in the natural assemblages. The conodont biostratigraphy indicates that the lithological boundary between chert and claystone units in the study section corresponds exactly to the Permian–Triassic boundary.     

Reversal of mutualism in a leafflower–leafflower moth association: the possible driving role of a third‐party partner

A major goal in the study of mutualism is to understand how co‐operation is maintained when mutualism may potentially turn into parasitism. Although certain mechanisms facilitate the persistence of mutualism, parasitic species have repeatedly evolved from mutualistic ancestors. However, documented examples of mutualism reversals are still rare. Leafflowers (Phyllantheae; Phyllanthaceae) include approximately 500 species that engage in obligate mutualism with leafflower moths (Epicephala; Gracillariidae), which actively pollinate flowers, and whose larvae feed on the resulting seeds. We found that the Taiwanese population of the Phyllanthus reticulatus species complex was associated with six sympatric Epicephala species, of which three were derived parasites that induced gall formation on flowers/buds and produced no seeds. Notably, two parasitic species have retained mutualistic pollination behaviour, suggesting that the parasitism was likely not selected for to reduce the cost of mutualism. We propose that the galling habit evolved as an adaptation to escape parasitism by a specialized braconid wasp. The tough gall produced by one species was almost free of braconid parasitism, and the swollen gall induced by the other species probably prevents attack as a result of the larger airspace inside the gall. Our findings suggest that the presence of a third‐party partner can greatly influence the evolutionary fate of mutualisms, regardless of whether the pairwise interaction continues to favour co‐operation.     

Host–parasite genotypic interactions in the honey bee: the dynamics of diversity

Parasites are thought to be a major driving force shaping genetic variation in their host, and are suggested to be a significant reason for the maintenance of sexual reproduction. A leading hypothesis for the occurrence of multiple mating (polyandry) in social insects is that the genetic diversity generated within‐colonies through this behavior promotes disease resistance. This benefit is likely to be particularly significant when colonies are exposed to multiple species and strains of parasites, but host–parasite genotypic interactions in social insects are little known. We investigated this using honey bees, which are naturally polyandrous and consequently produce genetically diverse colonies containing multiple genotypes (patrilines), and which are also known to host multiple strains of various parasite species. We found that host genotypes differed significantly in their resistance to different strains of the obligate fungal parasite that causes chalkbrood disease, while genotypic variation in resistance to the facultative fungal parasite that causes stonebrood disease was less pronounced. Our results show that genetic variation in disease resistance depends in part on the parasite genotype, as well as species, with the latter most likely relating to differences in parasite life history and host–parasite coevolution. Our results suggest that the selection pressure from genetically diverse parasites might be an important driving force in the evolution of polyandry, a mechanism that generates significant genetic diversity in social insects.     

Precambrian–Cambrian boundary interval occurrence and form of the enigmatic tubular body fossil Shaanxilithes ningqiangensis from the Lesser Himalaya of India

The affinity of the Ediacaran fossil Shaanxilithes ningqiangensis and putatively related forms has long been enigmatic; over the past few decades, interpretations ranging from trace fossils to algae to metazoans of uncertain phylogenetic placement have been proposed. Combined morphological and geochemical evidence from a new occurrence of S. ningqiangensis in the Krol and Tal groups of the Lesser Himalaya of India indicates that S. ningqiangensis is not a trace fossil, but rather an organic‐walled tubular body fossil of unknown taxonomic affinity. Specimens consist of compressed organic cylindrical structures, characterized by extended, overlapping or fragmented iterated units. Where specimens intersect, overlapping rather than branching or intraplanar crossing is observed. Lithologic comparisons and sequence stratigraphic data all suggest a late Ediacaran age for the uppermost Krol Group and basalmost Tal Group. By extending the biogeographical distribution of S. ningqiangensis, hitherto confined to the Ediacaran of China and potentially Siberia, to the Precambrian–Cambrian boundary interval of India, this new occurrence of S. ningqiangensis expands the biostratigraphic utility of this enigmatic fossil to the inter‐regional and intercontinental scale. Moreover, study of these new and exceptionally preserved samples may help to significantly constrain the long‐debated problem of Shaanxilithes' affinity, elucidating its ‘problematic’ status and shedding new light upon the ecology and taphonomy of one of the most significant intervals in early life history.     

Summer meeting 2013 – when the sleepers wake: the germination of spores of Bacillus species

Spores of Bacillus species can remain dormant and resistant for years, but can rapidly ‘come back to life’ in germination triggered by agents, such as specific nutrients, and non‐nutrients, such as CaDPA, dodecylamine and hydrostatic pressure. Major events in germination include release of spore core monovalent cations and CaDPA, hydrolysis of the spore cortex peptidoglycan (PG) and expansion of the spore core. This leads to a well‐hydrated spore protoplast in which metabolism and macromolecular synthesis begin. Proteins essential for germination include the GerP proteins that facilitate germinant access to spores' inner layers, germinant receptors (GRs) that recognize and respond to nutrient germinants, GerD important in rapid GR‐dependent germination, SpoVA proteins important in CaDPA release and cortex‐lytic enzymes that degrade cortex PG. Rates of germination of individuals in spore populations are heterogeneous, and methods have been developed recently to simultaneously analyse the germination of multiple individual spores. Spore germination heterogeneity is due primarily to large variations in GR levels among individual spores, with spores that germinate extremely slowly and termed superdormant having very low GR levels. These and other aspects of spore germination will be discussed in this review, and major unanswered questions will also be discussed.     

Competing for blood: the ecology of parasite resource competition in human malaria–helminth co‐infections

Ecological theory suggests that co‐infecting parasite species can interact within hosts directly, via host immunity and/or via resource competition. In mice, competition for red blood cells (RBCs) between malaria and bloodsucking helminths can regulate malaria population dynamics, but the importance of RBC competition in human hosts was unknown. We analysed infection density (i.e. the concentration of parasites in infected hosts), from a 2‐year deworming study of over 4000 human subjects. After accounting for resource‐use differences among parasites, we find evidence of resource competition, priority effects and a competitive hierarchy within co‐infected individuals. For example reducing competition via deworming increased Plasmodium vivax densities 2.8‐fold, and this effect is limited to bloodsucking hookworms. Our ecological, resource‐based perspective sheds new light into decades of conflicting outcomes of malaria–helminth co‐infection studies with significant health and transmission consequences. Beyond blood, investigating within‐human resource competition may bring new insights for improving human health.     

Scontrone (central Italy), signs of a 9‐million‐year‐old tragedy

The fossilierous bonebeds of Scontrone (Abruzzo region, central Italy) are preserved in tidal‐flat aeolian calcarenites at the base of the Lithothamnion Limestone, a Miocene carbonate ramp widespread in the central‐southern Apennines. The site bears evidence of a catastrophic event at 9 Ma. Reported are the results of the palaeobiological and taphonomic analysis conducted on the rich vertebrate assemblage, particularly on the remains of Hoplitomeryx (Mammalia, Artiodactyla, Ruminantia), recovered from the so‐called Scontrone calcarenites between 1992 and 2012. This is the first taphonomic study of a Late Miocene continental bone assemblage preserved in coastal deposits. The bones are not in primary context. They were likely exhumed during the initial phase of a marine transgression after a period of primary ‘storage’ within a possibly flood‐generated deposit in an estuarine environment. The mortality patterns indicate that the carcasses accumulated in a short time (within a year). The bones of the disarticulated skeletons were then removed, broken in a dry and brittle state, scattered over wide carbonate ramps along an arid to semi‐arid, wind‐exposed coastline and eventually buried again in aeolian calcarenites that drape transgressive tidal‐flat creek deposits. The analysis also reveals that hoplitomerycids were possibly seasonal reproducers and that the land they inhabited, the so‐called Apulia Platform, was probably swept by sudden, disastrous, storm‐supplied flash floods.     

Computer‐automated bird detection and counts in high‐resolution aerial images: a review

Bird surveys conducted using aerial images can be more accurate than those using airborne observers, but can also be more time‐consuming if images must be analyzed manually. Recent advances in digital cameras and image‐analysis software offer unprecedented potential for computer‐automated bird detection and counts in high‐resolution aerial images. We review the literature on this subject and provide an overview of the main image‐analysis techniques. Birds that contrast sharply with image backgrounds (e.g., bright birds on dark ground) are generally the most amenable to automated detection, in some cases requiring only basic image‐analysis software. However, the sophisticated analysis capabilities of modern object‐based image analysis software provide ways to detect birds in more challenging situations based on a variety of attributes including color, size, shape, texture, and spatial context. Some techniques developed to detect mammals may also be applicable to birds, although the prevalent use of aerial thermal‐infrared images for detecting large mammals is of limited applicability to birds because of the low pixel resolution of thermal cameras and the smaller size of birds. However, the increasingly high resolution of true‐color cameras and availability of small unmanned aircraft systems (drones) that can fly at very low altitude now make it feasible to detect even small shorebirds in aerial images. Continued advances in camera and drone technology, in combination with increasingly sophisticated image analysis software, now make it possible for investigators involved in monitoring bird populations to save time and resources by increasing their use of automated bird detection and counts in aerial images. We recommend close collaboration between wildlife‐monitoring practitioners and experts in the fields of remote sensing and computer science to help generate relevant, accessible, and readily applicable computer‐automated aerial photographic census techniques.     

Multiple guests in a single host: interactions across symbiotic and phytopathogenic bacteria in phloem‐feeding vectors – a review

Some pathogenic phloem‐limited bacteria are a major threat for worldwide agriculture due to the heavy economic losses caused to many high‐value crops. These disease agents – phytoplasmas, spiroplasmas, liberibacters, and Arsenophonus‐like bacteria – are transmitted from plant to plant by phloem‐feeding Hemiptera vectors. The associations established among pathogens and vectors result in a complex network of interactions involving also the whole microbial community harboured by the insect host. Interactions among bacteria may be beneficial, competitive, or detrimental for the involved microorganisms, and can dramatically affect the insect vector competence and consequently the spread of diseases. Interference is observed among pathogen strains competing to invade the same vector specimen, causing selective acquisition or transmission. Insect bacterial endosymbionts are another pivotal element of interactions between vectors and phytopathogens, because of their central role in insect life cycles. Some symbionts, either obligate or facultative, were shown to have antagonistic effects on the colonization by plant pathogens, by producing antimicrobial substances, by stimulating the production of antimicrobial substances by insects, or by competing for host infection. In other cases, the mutual exclusion between symbiont and pathogen suggests a possible detrimental influence on phytopathogens displayed by symbiotic bacteria; conversely, examples of microbes enhancing pathogen load are available as well. Whether and how bacterial exchanges occurring in vectors affect the relationship between insects, plants, and phytopathogens is still unresolved, leaving room for many open questions concerning the significance of particular traits of these multitrophic interactions. Such complex interplays may have a serious impact on pathogen spread and control, potentially driving new strategies for the containment of important diseases.     

Organ boundary NAC‐domain transcription factors are implicated in the evolution of petal fusion

• Research rationale: Evolution of fused petals (sympetaly) is considered to be an important innovation that has repeatedly led to increased pollination efficiency, resulting in accelerated rates of plant diversification. Although little is known about the underlying regulation of sympetaly, genetic pathways ancestrally involved in organ boundary establishment (e.g. CUP SHAPED COTYLEDON [CUC] 1–3 genes) are strong candidates. In sympetalous petunia, mutations in the CUC1/2‐like orthologue NO APICAL MERISTEM (NAM) inhibit shoot apical meristem formation. Despite this, occasional ‘escape shoots’ develop flowers with extra petals and fused inter‐floral whorl organs.
• Central methods: To To determine if petunia CUC‐like genes regulate additional floral patterning, we used virus‐induced silencing (VIGS) following establishment of healthy shoot apices to re‐examine the role of NAM in petunia petal development, and uniquely characterise the CUC3 orthologue NH16.
• Key results: Confirming previous results, we found that reduced floral NAM/NH16 expression caused increased petal–stamen and stamen–carpel fusion, and often produced extra petals. However, further to previous results, all VIGS plants infected with NAM or NH16 constructs exhibited reduced fusion in the petal whorl compared to control plants.
• Main conclusions: Together with previous data, our results demonstrate conservation of petunia CUC‐like genes in establishing inter‐floral whorl organ boundaries, as well as functional evolution to affect the fusion of petunia petals.