title: PeerJ description: Articles published in PeerJ link: https://peerj.com/articles/index.rss3?journal=peerj&page=1564 creator: info@peerj.com PeerJ errorsTo: info@peerj.com PeerJ language: en title: The variable monoaminergic outcomes of cleaner fish brains when facing different social and mutualistic contexts link: https://peerj.com/articles/4830 last-modified: 2018-05-24 description: The monoamines serotonin and dopamine are important neuromodulators present in the central nervous system, known to be active regulators of social behaviour in fish as in other vertebrates. Our aim was to investigate the region-specific brain monoaminergic differences arising when individual cleaners face a client (mutualistic context) compared to when they are introduced to another conspecific (conspecific context), and to understand the relevance of visual assessment compared to the impact of physical contact with any partner. We demonstrated that serotoninergic activity at the diencephalon responds mostly to the absence of physical contact with clients whereas cerebellar dopaminergic activity responds to actual cleaning engagement. We provide first insights on the brain’s monoaminergic (region-specific) response variations, involved in the expression of cleaner fishes’ mutualistic and conspecific behaviour. These results contribute to a better understanding of the monoaminergic activity in accordance to different socio-behavioural contexts. creator: Murilo S. de Abreu creator: João P.M. Messias creator: Per-Ove Thörnqvist creator: Svante Winberg creator: Marta C. Soares uri: https://doi.org/10.7717/peerj.4830 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 De Abreu et al. title: High correlation between skin color based on CIELAB color space, epidermal melanocyte ratio, and melanocyte melanin content link: https://peerj.com/articles/4815 last-modified: 2018-05-24 description: BackgroundTo treat skin color disorders, such as vitiligo or burns, melanocytes are transplanted for tissue regeneration. However, melanocyte distribution in the human body varies with age and location, making it difficult to select the optimal donor skin to achieve a desired color match. Determining the correlations with the desired skin color measurement based on CIELAB color, epidermal melanocyte numbers, and melanin content of individual melanocytes is critical for clinical application.MethodFifteen foreskin samples from Asian young adults were analyzed for skin color, melanocyte ratio (melanocyte proportion in the epidermis), and melanin concentration. Furthermore, an equation was developed based on CIELAB color with melanocyte ratio, melanin concentration, and the product of melanocyte ratio and melanin concentration. The equation was validated by seeding different ratios of keratinocytes and melanocytes in tissue-engineered skin substitutes, and the degree of fitness in expected skin color was confirmed.ResultsLinear regression analysis revealed a significant strong negative correlation (r =  − 0.847, R2 = 0.717) between CIELAB L* value and the product of the epidermal melanocyte ratio and cell-based melanin concentration. Furthermore, the results showed that an optimal skin color match was achieved by the formula.DiscussionWe found that L* value was correlated with the value obtained from multiplying the epidermal melanocyte ratio (R) and melanin content (M) and that this correlation was more significant than either L* vs M or L* vs R. This suggests that more accurate prediction of skin color can be achieved by considering both R and M. Therefore, precise skin color match in treating vitiligo or burn patients would be potentially achievable based on extensive collection of skin data from people of Asian descent. creator: Wen-Shyan Huang creator: Yi-Wen Wang creator: Kun-Che Hung creator: Pai-Shan Hsieh creator: Keng-Yen Fu creator: Lien-Guo Dai creator: Nien-Hsien Liou creator: Kuo-Hsing Ma creator: Jiang-Chuan Liu creator: Niann-Tzyy Dai uri: https://doi.org/10.7717/peerj.4815 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Huang et al. title: Water mites (Acari, Hydrachnidia) of riparian springs in a small lowland river valley: what are the key factors for species distribution? link: https://peerj.com/articles/4797 last-modified: 2018-05-24 description: This paper examines the impact of disturbance factors—flooding and intermittency—on the distribution of water mites in the riparian springs situated in the valley of a small lowland river, the Krąpiel. The landscape factors and physicochemical parameters of the water were analysed in order to gain an understanding of the pattern of water mite assemblages in the riparian springs. Three limnological types of springs were examined (helocrenes, limnocrenes and rheocrenes) along the whole course of the river and a total of 35 water mite species were found. Our study shows that flooding influences spring assemblages, causing a decrease in crenobiontic water mites in flooded springs. The impact of intermittency resulted in a high percentage of species typical of temporary water bodies. Surprisingly, the study revealed the positive impact of the anthropogenic transformation of the river valley: preventing the riparian springs from flooding enhances the diversity of crenobiontic species in non-flooded springs. In the conclusion, our study revealed that further conservation strategies for the protection of the riparian springs along large rivers would take into account ongoing climatic changes and possible the positive impact of the anthropogenic transformation of river valleys. creator: Andrzej Zawal creator: Robert Stryjecki creator: Edyta Buczyńska creator: Paweł Buczyński creator: Joanna Pakulnicka creator: Aleksandra Bańkowska creator: Tomasz Czernicki creator: Katarzyna Janusz creator: Agnieszka Szlauer-Łukaszewska creator: Vladimir Pešić uri: https://doi.org/10.7717/peerj.4797 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Zawal et al. title: The role of gut microbiota in the regulation of standard metabolic rate in female Periplaneta americana link: https://peerj.com/articles/4717 last-modified: 2018-05-24 description: Insect gut microbiota contribute significantly to host nutritional ecology. Disrupting insect gut microbial assemblages impacts nutrient provisioning functions, and can potentially affect host standard metabolic rate (SMR), a measure of host energy balance. In this study, we evaluated the effect of disrupting gut microbial assemblages on the SMR of female Periplaneta americana cockroaches fed dog food (DF, high protein/carbohydrate (p/c) ratio), and cellulose-amended dog food (CADF, 30% dog food, 70% cellulose, low p/c ratio) diets, supplemented with none, low, or high antibiotic doses. Bacterial loads decreased significantly between diet types (P = 0.04) and across antibiotic doses (P = 0.04). There was a significant diet type x antibiotic dose interaction on SMR of females on both diets (P = 0.05) by the end of the seven-day experimental period. In CADF-fed females, SMR decreased linearly with decreasing bacterial load. However, SMR of DF-fed females on the low dose was significantly higher than those in the control and high dose groups. This is interpreted as a diet-dependent response by low dose DF-fed females to the loss of nutritional services provided by gut bacteria. Severe reductions in bacterial load at high doses reduced SMR of females on both diet types. This study provides insights into the potential role of gut bacteria as modulators of host energy expenditure under varying dietary conditions. creator: Paul A. Ayayee creator: Andrew Ondrejech creator: George Keeney creator: Agustí Muñoz-Garcia uri: https://doi.org/10.7717/peerj.4717 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2018 Ayayee et al. title: Planning protected areas network that are relevant today and under future climate change is possible: the case of Atlantic Forest endemic birds link: https://peerj.com/articles/4689 last-modified: 2018-05-24 description: BackgroundA key strategy in biodiversity conservation is the establishment of protected areas. In the future, however, the redistribution of species in response to ongoing climate change is likely to affect species’ representativeness in those areas. Here we quantify the effectiveness of planning protected areas network to represent 151 birds endemic to the Brazilian Atlantic Forest hotspot, under current and future climate change conditions for 2050.MethodsWe combined environmental niche modeling and systematic conservation planning using both a county and a regional level planning strategy. We recognized the conflict between biodiversity conservation and economic development, including socio-economic targets (as opposed to biological only) and using planning units that are meaningful for policy-makers.ResultsWe estimated an average contraction of 29,500 km2 in environmentally suitable areas for birds, representing 52% of currently suitable areas. Still, the most cost-effective solution represented almost all target species, requiring only ca. 10% of the Atlantic Forest counties to achieve that representativeness, independent of strategy. More than 50% of these counties were selected both in the current and future planned networks, representing >83% of the species.DiscussionOur results indicate that: (i) planning protected areas network currently can be useful to represent species under climate change; (ii) the overlapped planning units in the best solution for both current and future conditions can be considered as “no regret” areas; (iii) priority counties are spread throughout the biome, providing specific guidance wherever the possibility of creating protected area arises; and (iv) decisions can occur at different administrative spheres (Federal, State or County) as we found quite similar numerical solutions using either county or regional level strategies. creator: Mariana M. Vale creator: Thiago V. Souza creator: Maria Alice S. Alves creator: Renato Crouzeilles uri: https://doi.org/10.7717/peerj.4689 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Vale et al. title: Altitudinal patterns in breeding bird species richness and density in relation to climate, habitat heterogeneity, and migration influence in a temperate montane forest (South Korea) link: https://peerj.com/articles/4857 last-modified: 2018-05-23 description: Altitudinal patterns in the population ecology of mountain bird species are useful for predicting species occurrence and behavior. Numerous hypotheses about the complex interactions among environmental factors have been proposed; however, these still remain controversial. This study aimed to identify the altitudinal patterns in breeding bird species richness or density and to test the hypotheses that climate, habitat heterogeneity (horizontal and vertical), and heterospecific attraction in a temperate forest, South Korea. We conducted a field survey of 142 plots at altitudes between 200 and 1,400 m a.s.l in the breeding season. A total of 2,771 individuals from 53 breeding bird species were recorded. Altitudinal patterns of species richness and density showed a hump-shaped pattern, indicating that the highest richness and density could be observed at moderate altitudes. Models constructed with 13 combinations of six variables demonstrated that species richness was positively correlated with vertical and horizontal habitat heterogeneity. Density was positively correlated with vertical, but not horizontal habitat heterogeneity, and negatively correlated with migratory bird ratio. No significant relationships were found between spring temperature and species richness or density. Therefore, the observed patterns in species richness support the hypothesis that habitat heterogeneity, rather than climate, is the main driver of species richness. Also, neither habitat heterogeneity nor climate hypotheses fully explains the observed patterns in density. However, vertical habitat heterogeneity does likely help explain observed patterns in density. The heterospecific attraction hypothesis did not apply to the distribution of birds along the altitudinal gradient. Appropriate management of vertical habitat heterogeneity, such as vegetation cover, should be maintained for the conservation of bird diversity in this area. creator: Jin-Yong Kim creator: Sanghun Lee creator: Man-Seok Shin creator: Chang-Hoon Lee creator: Changwan Seo creator: Soo Hyung Eo uri: https://doi.org/10.7717/peerj.4857 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2018 Kim et al. title: Primate occurrence across a human-impacted landscape in Guinea-Bissau and neighbouring regions in West Africa: using a systematic literature review to highlight the next conservation steps link: https://peerj.com/articles/4847 last-modified: 2018-05-23 description: BackgroundWest African landscapes are largely characterised by complex agroforest mosaics. Although the West African forests are considered a nonhuman primate hotspot, knowledge on the distribution of many species is often lacking and out-of-date. Considering the fast-changing nature of the landscapes in this region, up-to-date information on primate occurrence is urgently needed, particularly of taxa such as colobines, which may be more sensitive to habitat modification than others. Understanding wildlife occurrence and mechanisms of persistence in these human-dominated landscapes is fundamental for developing effective conservation strategies.MethodsIn this paper, we aim to review current knowledge on the distribution of three threatened primates in Guinea-Bissau and neighbouring regions, highlighting research gaps and identifying priority research and conservation action. We conducted a systematic literature review of primate studies from 1976 to 2016 in Guinea-Bissau, southern Senegal and western Guinea (Boké Region). We mapped historical observation records of chimpanzee (Pan troglodytes verus), Temminck’s red colobus (Pilicolobus badius temminckii) and king colobus (Colobus polykomos), including our preliminary survey data from Dulombi, a newly established National Park (NP) in Guinea-Bissau.ResultsWe found 151 documents, including 87 journal articles, that contained field data on primates in this region. In Guinea-Bissau, nearly all studies focussed south of the Corubal River, including mainly Cantanhez, Cufada, and Boé NP’s. In Senegal, most of the data came from Fongoli and Niokolo-Koba NP. In Boké (Guinea) studies are few, with the most recent data coming from Sangarédi. In Dulombi NP we recorded eight primate species, including chimpanzees, red colobus and king colobus. Across the selected region, chimpanzees, red colobus and king colobus were reported in eleven, twelve and seven protected areas, respectively.DiscussionOur study demonstrates large geographical research gaps particularly for the two colobines. For the first time after more than two decades, we confirm the presence of red colobus and king colobus north of the Corubal River in Guinea-Bissau. The little information available from large parts of the red colobus range raises questions regarding levels of population fragmentation in this species, particularly in Casamance and across northern Guinea-Bissau. There are still no records demonstrating the occurrence of king colobus in Senegal, and the presence of a viable population in north-eastern Guinea-Bissau remains uncertain. While the occurrence of chimpanzees in Guinea-Bissau and Senegal is well documented, data from Boké (Guinea) are sparse and out-of-date. Our approach—the mapping of data gathered from a systematic literature review—allows us to provide recommendations for selecting future geographical survey locations and planning further research and conservation strategies in this region. creator: Elena Bersacola creator: Joana Bessa creator: Amélia Frazão-Moreira creator: Dora Biro creator: Cláudia Sousa creator: Kimberley Jane Hockings uri: https://doi.org/10.7717/peerj.4847 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Bersacola et al. title: Impact of crop residue management on crop production and soil chemistry after seven years of crop rotation in temperate climate, loamy soils link: https://peerj.com/articles/4836 last-modified: 2018-05-23 description: Society is increasingly demanding a more sustainable management of agro-ecosystems in a context of climate change and an ever growing global population. The fate of crop residues is one of the important management aspects under debate, since it represents an unneglectable quantity of organic matter which can be kept in or removed from the agro-ecosystem. The topic of residue management is not new, but the need for global conclusion on the impact of crop residue management on the agro-ecosystem linked to local pedo-climatic conditions has become apparent with an increasing amount of studies showing a diversity of conclusions. This study specifically focusses on temperate climate and loamy soil using a seven-year data set. Between 2008 and 2016, we compared four contrasting residue management strategies differing in the amount of crop residues returned to the soil (incorporation vs. exportation of residues) and in the type of tillage (reduced tillage (10 cm depth) vs. conventional tillage (ploughing at 25 cm depth)) in a field experiment. We assessed the impact of the crop residue management on crop production (three crops—winter wheat, faba bean and maize—cultivated over six cropping seasons), soil organic carbon content, nitrate (${\mathrm{NO}}_{3}^{-}$NO3−), phosphorus (P) and potassium (K) soil content and uptake by the crops. The main differences came primarily from the tillage practice and less from the restitution or removal of residues. All years and crops combined, conventional tillage resulted in a yield advantage of 3.4% as compared to reduced tillage, which can be partly explained by a lower germination rate observed under reduced tillage, especially during drier years. On average, only small differences were observed for total organic carbon (TOC) content of the soil, but reduced tillage resulted in a very clear stratification of TOC and also of P and K content as compared to conventional tillage. We observed no effect of residue management on the ${\mathrm{NO}}_{3}^{-}$NO3− content, since the effect of fertilization dominated the effect of residue management. To confirm the results and enhance early tendencies, we believe that the experiment should be followed up in the future to observe whether more consistent changes in the whole agro-ecosystem functioning are present on the long term when managing residues with contrasted strategies. creator: Marie-Pierre Hiel creator: Sophie Barbieux creator: Jérôme Pierreux creator: Claire Olivier creator: Guillaume Lobet creator: Christian Roisin creator: Sarah Garré creator: Gilles Colinet creator: Bernard Bodson creator: Benjamin Dumont uri: https://doi.org/10.7717/peerj.4836 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Hiel et al. title: Predicting the potential distributions of the invasive cycad scale Aulacaspis yasumatsui (Hemiptera: Diaspididae) under different climate change scenarios and the implications for management link: https://peerj.com/articles/4832 last-modified: 2018-05-23 description: Cycads are an ancient group of gymnosperms that are popular as landscaping plants, though nearly all of them are threatened or endangered in the wild. The cycad aulacaspis scale (CAS), Aulacaspis yasumatsui Takagi (Hemiptera: Diaspididae), has become one of the most serious pests of cycads in recent years; however, the potential distribution range and the management approach for this pest are unclear. A potential risk map of cycad aulacaspis scale was created based on occurrence data under different climatic conditions and topology factors in this study. Furthermore, the future potential distributions of CAS were projected for the periods 2050s and 2070s under three different climate change scenarios (GFDL-CM3, HADGEM2-AO and MIROC5) described in the Special Report on Emissions Scenarios of the IPCC (Intergovernmental Panel on Climate Change). The model suggested high environmental suitability for the continents of Asia and North America, where the species has already been recorded. The potential distribution expansions or reductions were also predicted under different climate change conditions. Temperature of Driest Quarter (Bio9) was the most important factor, explaining 48.1% of the distribution of the species. The results also suggested that highly suitable habitat for CAS would exist in the study area if the mean temperature of 15–20 °C in the driest quarter and a mean temperature of 25–28 °C the wettest quarter. This research provides a theoretical reference framework for developing policy to manage and control this invasive pest. creator: Jiufeng Wei creator: Qing Zhao creator: Wanqing Zhao creator: Hufang Zhang uri: https://doi.org/10.7717/peerj.4832 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Wei et al. title: Taxonomic monograph of Oxygyne (Thismiaceae), rare achlorophyllous mycoheterotrophs with strongly disjunct distribution link: https://peerj.com/articles/4828 last-modified: 2018-05-23 description: Oxygyne Schltr. (Thismiaceae) is a rare and little-known genus of achlorophyllous mycoheterotrophic perennial herbs with one of the most remarkable distributions of all angiosperm plant genera globally, being disjunct between Japan and West–Central Africa. Each species is known only from a single location, and in most cases from a single specimen. This monographic study names, describes and maps two new species, Oxygyne duncanii Cheek from cloud forest in SW Region Cameroon and O. frankei Cheek from gallery forest in the Central African Republic, representing the first new Oxygyne species described from Africa in 112 years, and raising the number of described Oxygyne species from four to six. Oxygyne duncanii is remarkable for sharing more morphological characters with two of the three Japanese species (O. hyodoi C.Abe & Akasawa, O. shinzatoi (H. Ohashi) Tsukaya) than with the geographically much closer type species of the genus, O. triandra from Mt Cameroon. Based mainly on herbarium specimens and field observations made in Cameroon and Japan during a series of botanical surveys, we provide descriptions, synonymy, mapping and extinction risk assessments for each species of Oxygyne, together with keys to the genera of Thismiaceae and the species of Oxygyne. The subterranean structures of African Oxygyne are described for the first time, and found to be consistent with those of the Japanese species. We review and reject an earlier proposal that the Japanese species should be segregated from the African species as a separate genus, Saionia Hatus. The only character that separates the two disjunct species groups is now flower colour: blue or partly-blue in the Japanese species compared with orange-brown in the African species. Studies of the pollination biology and mycorrhizal partners of Oxygyne are still lacking. Two of the six species, O. triandra Schltr. and O. hyodoi, appear to be extinct, and the remaining four are assessed as Critically Endangered using the IUCN 2012 criteria. To avoid further extinction, an urgent requirement is for conservation management of the surviving species in the wild. Since few achlorophyllous mycoheterotrophs have been successfully cultivated from seed to maturity, ex situ conservation will not be viable for these species and protection in the wild is the only viable option. While natural habitat survives, further botanical surveys could yet reveal additional new species between Central Africa and Japan. creator: Martin Cheek creator: Hirokazu Tsukaya creator: Paula J. Rudall creator: Kenji Suetsugu uri: https://doi.org/10.7717/peerj.4828 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Cheek et al.