Butterflies of European islands: the implications of the geography and ecology of rarity and endemicity for conservation

Depending on their faunal content islands can function as important ‘vehicles’ for conservation. In this study, we examine data on 440 butterfly species over 564 European islands in 10 island groups. To determine the status of the butterfly fauna, we have adopted two approaches, island-focused and species-focused, examined using principal components analysis and regression modelling. In the former, we relate species richness, rarity and endemicity to island geography (area, elevation, isolation and location in latitude and longitude); in the latter, species occurrence on islands is examined in relation to distribution, range, range boundaries, and altitudinal limits on the continent as well as species’ ecology (number of host plants) and morphology (wing expanse). Species on islands are also assessed for their status on the continental mainland, their distributional dynamics (extinctions, distribution changes) and conservation status (Red Data Book, European Habitat Directive, Species of European Conservation Concern and Bern Convention listing. Unexpectedly, we find that a large fraction of the European butterfly species is found on the islands (63.4%; 59% on small islands) comprising some 6.2% of the land area of Europe. Although species occurring on the islands tend, on the whole, to have lower conservation status and are not declining over Europe, 45 species are endemics restricted to the islands. Species richness shows only a weak locational pattern and is related as expected to isolation from the continental source and island area; but, both rarity and endemicity have distinctive geographical bias to southern Europe, on islands now under increasing pressure from climate change and increasingly intensive human exploitation. The vulnerability of species on islands is emphasised in the relationship of island occurrence (% occurrence and presence/absence of species on any island) with continental distributions. A large proportion of the variation (84%) is accounted by continental distribution, the southern range limit and lower altitudinal limit. Most species (69%) occur on very few islands (<5%). In view of ongoing species dynamics on islands, migrations and extinctions of species, island repositories of species depend in large part on conservation of butterflies at continental sources. The unique faunas and rare species on islands also depend on appropriate concern being given to the island faunas. Conservation of European islands is thus a two-way process, sustaining sources and conserving island refuges. Residuals from the regressions (islands with more or fewer species, rare and endemic species; species occurring more or less frequently than expected on islands) provide warning signals of regions and islands deserving immediate attention.     

Identification of seagrasses in the gut of a marine herbivorous fish using DNA barcoding and visual inspection techniques

Traditional visual diet analysis techniques were compared with DNA barcoding in juvenile herbivorous rabbitfish Siganus fuscescens collected in Moreton Bay, Australia, where at least six species of seagrass occur. The intergenic spacer trnH-psbA, suggested as the optimal gene for barcoding angiosperms, was used for the first time to identify the seagrass in fish guts. Four seagrass species and one alga were identified visually from gut contents; however, there was considerable uncertainty in visual identification with 38 of 40 fish having unidentifiable plant fragments in their gut. PCR and single-strand conformational polymorphism (SSCP) were able to discriminate three seagrass families from visually cryptic gut contents. While effective in identifying cryptic gut content to family level, this novel method is likely to be most efficient when paired with visual identification techniques.     

Carboxypeptidase E, a prohormone sorting receptor, is anchored to secretory granules via a C-terminal transmembrane insertion.

Carboxypeptidase E (CPE) is a sorting receptor that directs the prohormone pro-opiomelanocortin (POMC) to the regulated secretory pathway, and is also a prohormone processing enzyme in neuro/endocrine cells. It has been suggested that the 25 C-terminal amino acids are necessary for the binding of CPE to secretory granule membranes, but its orientation in the membrane is not known. In this study, we examined the structure and orientation of the membrane-binding domain at the C-terminus of CPE. In vitro experiments using model membranes demonstrated that the last 22 amino acids of CPE (CP peptide) insert in a shallow orientation into lipid bilayers at low pH. Circular dichroism analysis indicated that the CP peptide adopts a partial alpha-helical configuration at low pH, and helix content increases when it is bound to lipid. Protease protection experiments, immunolabeling, and immunoisolation of intact secretory granules with a C-terminal antibody revealed a cytoplasmic domain in CPE, consistent with a transmembrane orientation of this protein. We conclude that the membrane-binding domain of CPE must adopt an alpha-helical configuration to bind to lipids, and that CPE may require another integral membrane "chaperone" protein to insert through the lipid bilayer in a transmembrane fashion.     

Molecular analysis of gene expression in the developing pontocerebellar projection system

As an approach toward understanding the molecular mechanisms of neuronal differentiation, we utilized DNA microarrays to elucidate global patterns of gene expression during pontocerebellar development. Through this analysis, we identified groups of genes specific to neuronal precursor cells, associated with axon outgrowth, and regulated in response to contact with synaptic target cells. In the cerebellum, we identified a phase of granule cell differentiation that is independent of interactions with other cerebellar cell types. Analysis of pontine gene expression revealed that distinct programs of gene expression, correlated with axon outgrowth and synapse formation, can be decoupled and are likely influenced by different cells in the cerebellar target environment. Our approach provides insight into the genetic programs underlying the differentiation of specific cell types in the pontocerebellar projection system.     

The Group A Streptococcus serotype M2 pilus plays a role in host cell adhesion and immune evasion

Group A Streptococcus (GAS), or Streptococcus pyogenes, is a human pathogen that causes diseases ranging from skin and soft tissue infections to severe invasive diseases, such as toxic shock syndrome. Each GAS strain carries a particular pilus type encoded in the variable f ibronectin‐binding, c ollagen‐binding, T antigen (FCT) genomic region. Here, we describe the functional analysis of the serotype M2 pilus encoded in the FCT‐6 region. We found that, in contrast to other investigated GAS pili, the ancillary pilin 1 lacks adhesive properties. Instead, the backbone pilin is important for host cell adhesion and binds several host factors, including fibronectin and fibrinogen. Using a panel of recombinant pilus proteins, GAS gene deletion mutants and Lactococcus lactis gain‐of‐function mutants we show that, unlike other GAS pili, the FCT‐6 pilus also contributes to immune evasion. This was demonstrated by a delay in blood clotting, increased intracellular survival of the bacteria in macrophages, higher bacterial survival rates in human whole blood and greater virulence in a Galleria mellonella infection model in the presence of fully assembled FCT‐6 pili.     

Using miniaturized radiotelemetry to discover the breeding grounds of the endangered New Zealand Storm Petrel Fregetta maoriana

Identification of breeding sites remains a critical step in species conservation, particularly in procellariiform seabirds whose threat status is of global concern. We designed and conducted an integrative radiotelemetry approach to uncover the breeding grounds of the critically endangered New Zealand Storm Petrel Fregetta maoriana (NZSP), a species considered extinct before its rediscovery in 2003. Solar‐powered automated radio receivers and hand‐held telemetry were used to detect the presence of birds on three island groups in the Hauraki Gulf near Auckland, New Zealand. At least 11 NZSP captured and radiotagged at sea were detected at night near Te Hauturu‐o‐Toi/Little Barrier Island with the detection of an incubating bird leading to the discovery of the first known breeding site for this species. In total, four NZSP breeding burrows were detected under mature forest canopy and three adult NZSP and two NZSP chicks were ringed. Telemetry data indicated NZSP showed strong moonlight avoidance behaviour over the breeding site, had incubation shifts of approximately 5 days and had a breeding season extending from February to June/July, a different season from other Procellariiformes in the region. Radiotelemetry, in combination with rigorously collected field data on species distribution, offers a valuable technique for locating breeding grounds of procellariiform seabirds and gaining insights into breeding biology while minimizing disturbance to sensitive species or damage to fragile habitat. Our study suggests an avenue for other breeding ground searches in one of the most threatened avian Orders, and highlights the general need for information on the location of breeding sites and understanding the breeding biology in data‐deficient birds.