Implication for DNA methylation involved in the host transfer of diamondback moth,Plutella xylostella (L.)

DNA methylation exerts extensive impacts on gene expression of various living organisms exposed to environmental variation. However, little is known whether DNA methylation is involved in the host transfer of diamondback moth, Plutella xylostella (L.), a worldwide destructive pest of crucifers. In this study, we found that P. xylostella genome exhibited a relatively low level of DNA methylation on the basis of the CpG O/E prediction and experimental validation. A significant positive linear correlation was observed between the stage‐specific expressions of PxDNMT1 and DNA methylation levels (5mC content). Particularly, high levels of DNA methylation and gene expression of PxDNMT1 were observed in eggs and mature females of P. xylostella. After host transfer of P. xylostella from Raphanus sativus to Arabidopsis thaliana, we identified some potential genomic loci that might have changed methylation levels. Using the method of fluorescence‐labeled methylation‐sensitive amplified polymorphism (F‐MSAP), we also found the corresponding genes primarily involved in neural system and signaling. The expressions of six candidate genes were verified by qRT‐PCR. One of the genes, Px009600, might be regulated by a DNA methylation‐mediated mechanism in response to host transfer. Our study provides evidence for a functional system of DNA methylation in P. xylostella and its possible role in adaptation during host transfer. Further studies should examine methylation as responsive factors to different host plants and environmental cues in insect pests.     

Are black flies of the subgenus Wilhelmia (Diptera: Simuliidae) multiple species or a single geographical generalist? Insights from the macrogenome

Organisms with vast distributions often represent geographical mosaics of cryptic species. The black fly Simulium (Wilhelmia) lineatum is among the most widely distributed members of the family Simuliidae, ranging from the British Isles to eastern China. Rather than viewing S. lineatum as a possible aggregate of multiple species, taxonomists have suggested a more inclusive taxon with additional synonyms. Accordingly, S. lineatum is an ideal candidate for testing the hypothesis that a wide geographical distribution signals the presence of more than one species. A cytogenetic approach was used to probe the macrogenome of S. lineatum and other taxa proposed by taxonomists as conspecific. The banding patterns in the polytene chromosomes of 480 larvae from 15 countries across the Palearctic Region revealed 128 rearrangements of the complement. All rearrangements were autosomal and 89% were inversions nonrandomly distributed among species and among chromosome arms. The analyses clarify long‐standing confusion over previously proposed names and reveal a longitudinal succession of four species sequentially replacing one another from west to east: Simulium lineatum s.s., Simulium balcanicum, Simulium turgaicum, and Simulium takahasii. Thus, S. turgaicum is recalled from synonymy and the other three species are validated. Within the most‐represented species, S. balcanicum, the frequency of inversions follows a longitudinal gradient with a north–south bias; as the distance between the sites increases along this north‐west–south‐east axis, the similarity of inversion frequencies between sites decreases. Validation of the concept that broadly distributed black flies are composites of structurally similar species provides a framework for guiding discovery of additional biodiversity. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 114 , 163–183.     

Decline and potential recovery of Yellow-footed Antechinus in parts of south-eastern Australia: A perspective with implications for management

Summary   The extent and intensity of European-induced changes to ecosystems in south-eastern Australia mean that remaining habitats, despite being degraded, are of high conservation value. Given the extinction of several species of native mammals in the last 160 years in the area, and conservation concerns regarding others, it is important to provide conservation managers with sufficient information to prevent further extinctions and maintain evolutionary potential of the species. A native, carnivorous marsupial, the Yellow-footed Antechinus ( Antechinus flavipes ) exists within these massively altered landscapes. We present conceptual models, derived from the literature, of persistence of populations of Yellow-footed Antechinus both before European colonization and in the 21st century. We conclude that preservation of large trees, restoration of fallen-timber volumes, spring flooding of floodplains and presence of vegetation corridors between forests should be undertaken to prevent local extinctions of Yellow-footed Antechinus. From historic and current gene flow, we identify remnant woodland and forest groupings that we consider should be managed as coherent units.     

Specific diversity of plant populations at rainfed scale and crop protection: the example of banana production in the French West Indies

Banana is a major crop in the French West Indies, where it is subjected to strong parasite pressure, resulting in pesticide pollution. An increase in plant population diversity in the cultivated ecosystem is generated by changing cultural practices. This results in a decrease in parasite pressure and hence a decrease in pollutant pesticide loads. Agricultural sustainability is therefore reinforced for better coexistence of populated, cultivated and protected areas.     

Behavioural responses of Oryzaephilus surinamensis, Tribolium castaneum and Tribolium confusum to naturally and artificially damaged durum wheat kernels

Observations on behavioural activity involved in the host selection by secondary pests of stored grains, Oryzaephilus surinamensis (Linnaeus), Tribolium castaneum (Herbst) and Tribolium confusum J. du Val, with respect to intact and mechanically or naturally damaged kernels are reported. Our results indicate that the attraction of secondary pests is facilitated by broken grain kernels, which resulted from either mechanical damage during harvesting and/or binning procedures, or the feeding activity of primary insect pests. Insect damaged kernels were more attractive to O. surinamensis, T. castaneum and T. confusum than whole kernels; in addition insect damaged kernels elicit more attractiveness than mechanically split kernels. The damage caused by primary pests, such as Rhyzopertha dominica (Fabricius) and Sitophilus oryzae (Linnaeus), on whole kernels may facilitate colonization by secondary pests, which continue damaging the cereals. O. surinamensis, T. castaneum and T. confusum utilize the grain volatile odours to distinguish whether the grain kernels of the stored cereals are damaged mechanically or by insects.     

Floodplain ants show a stronger response to an extensive flood than to variations in fallen‐timber load

Understanding how species respond to differences in resource availability is critical to managing biodiversity under the increasing pressures associated with climate change and growing human populations. Over the last century, the floodplain forests of Australia's largest river system, the Murray‐Darling Basin, have been much affected by intensive harvesting of timber and firewood, and increasingly stressed by river regulation and, recently, an extended drought. Fallen timber – logs and shed branches – is known to play a key role in the ecology of several important species on these floodplains. Here, we monitored the response of the ant assemblages of a floodplain forest along the Murray River to a large‐scale (34 ha) experimental manipulation of fallen‐timber load (0 to 80 t ha^?1) over 4 years. The forest was subjected to an incidental, extensive flood that enabled us to examine how two important stressors (timber removal and river regulation) affect ant assemblages. Ants showed little response to the proximity of fallen timber within plots, prior to the flood, or to different loads among plots, unlike other floodplain biota. After the flood, both ant abundance and species richness increased and species composition changed. However, this increase in species richness after flooding was less pronounced in plots with higher amounts of fallen timber. Managing river red gum forest using a mosaic of flood regimes, more representative of historical conditions, is likely to be the most effective way to maintain and enhance the diversity of ants and other biota on these important floodplains.     

Designing Timber Harvesting to Enhance New Zealand Falcon Populations

Previous breeding-season studies of threatened New Zealand falcons (Falco novaeseelandiae) in plantation forests have suggested that falcons benefit when harvesting creates a mosaic of differently aged stands, especially where young and mature tree stands are adjacent. Thus, changes in the rate and pattern of harvesting may affect habitat heterogeneity by altering the size and distribution of forest patches. We sought to determine guidelines for harvesting that would most benefit falcons by increasing the carrying capacity of the forest for falcons. We used radio-tracking to determine the home-range sizes of non-breeding falcons over 3 seasons and compared winter home-range overlap in the most-selected land cover types by falcons (mature-young edges and open patches) with other land cover types. The distribution of open patches and edges between mature stands and recently cleared areas affected falcon home ranges, home-range overlap, and the likelihood of nesting. Specifically, home ranges were smaller as the density of edges and percentage of open patch increased, and there was greater home-range overlap between individuals in the most-selected land cover types. Numbers of falcons decreased as the size of open patches increased, concomitant with a decrease in edge size, the number of edge borders, and the number of open patches. The likelihood of nesting also decreased as open patch size increased. Our results indicate that smaller open patches spread through a forest, maximizing the amount of mature-young edges, will favor smaller home ranges and therefore potentially greater numbers of falcons. We recommend harvesting protocols that ensure that open patches (0–3-yr-old stands) are <4 km² in size and retain at least small stands of mature pine to maintain a high density of edges. Similar protocols may increase the carrying capacity for other species occurring in managed systems involving fragmented landscapes or small reserves. © 2021 The Wildlife Society.     

Global trends of habitat destruction and consequences for parrot conservation

Human advance on natural habitats is a major cause of biodiversity loss. This transformation process represents a profound change in wooded environments, disrupting original communities of flora and fauna. Many species are highly dependent on forests, especially parrots (Psittaciformes) with almost a third of their species threatened by extinction. Most parrot species occur in tropical and subtropical forests, and given the forest dependence of most species, this is the main reason why habitat loss has been highlighted as the main threat for the group. Such habitat loss acts in synergy with other important threats (e.g., logging and poaching), which become especially problematic in certain developing countries along tropical latitudes. In this study, we used available information on parrot distributions, species traits, IUCN assessment, habitat loss and timber extraction for different periods, and distribution of protected areas, to determine conservation hotspots for the group, and analyze potential changes in the conservation status of these species. We detected four conservation hotspots for parrots: two in the Neotropics and two in Oceania, all of them facing different degrees of threat in regard of current habitat loss and agricultural trends. Our results suggest that the future of the group is subject to policymaking in specific regions, especially in the northeastern Andes and the Atlantic Forest. In addition, we predicted that agricultural expansion will have a further negative effect on the conservation status of parrots, pushing many parrot species to the edge of extinction in the near future. Our results have conservation implications by recommending protected areas in specific parrot conservation hotspots. Our recommendations to mitigate conservation risks to this group of umbrella species would also benefit many other coexisting species as well.     

Reworking the idea of chestnut (Castanea sativa Mill.) cultivation in Roman times: New data from ancient Campania

Abstract

Charcoal analysis was carried out in two archaeological sites on the north slope of the Somma-Vesuvius volcano, not far from Naples. Both sites were inhabited between the 2nd century AD and AD 472, when a great Vesuvius eruption (so called Pollena eruption) buried them. In both sites, Castanea sativa wood was largely used for architectural structures as well as firewood. Ten ¹⁴C dates, spanning between the 1st and the 5th century AD, testify to a continuative use of this wood throughout the life of the sites. The comparison between archaeobotanical and pollen data from other sites in southern Italy suggests that chestnut woods were close to the sites studied and had a restricted spreading, possibly in a refugium area on Vesuvius' foothills. The match between archaeological charcoals and pollen data suggests that the Romans did not spread chestnut cultivation in the entire Campania region and that chestnut probably became a common timber in Campania starting from the 5th–6th century AD.