The effect of different UV and calcium provisioning on health and fitness traits of red-eyed tree frogs (Agalychnis callidryas)

In response to global amphibian declines and extinctions, the IUCN has recommended the establishment of ex situ conservation breeding programmes. However, there are a limited number of studies that scientifically assess amphibian husbandry practices, even at a basic level of nutrition and lighting. One component of captive husbandry that is increasingly discussed is the provision of ultraviolet radiation (UVR), which is required for the synthesis of vitamin D3 and subsequent assimilation of calcium and phosphorous from the diet. Here we used two methods of UV provision (“background UV” and “background UV with UV boost”) and two calcium gut-loading diets (5% and 10%) to assess the effects on a range of fitness measures in the red-eyed tree frog (Agalychnis callidryas). We found no effects of either UV treatment or calcium diet on growth, body condition or cutaneous bacterial communities of frogs, although subsequent to the UV boost, frogs had a significantly greater fungal load in comparison to frogs that were not UV-boosted. There were negligible differences in the breeding success of females according to UV exposure. Provision of the UV boost was not demonstrated to provide any real advantages for A. callidryas in terms of growth or breeding success. In addition, there were no benefits of a 10% calcium diet over a 5% calcium diet (in conjunction with regular dusting). Further studies that investigate the UV requirements of other amphibian species and ecotypes are required, particularly in conjunction with naturalistic cricket gut-loading diets

Quantitative Trait Loci mapping of phenotypic plasticity and genotype – environment interactions in plant and insect performance

Community genetic studies generally ignore the plasticity of the functional traits through which the effect is passed from individuals to the associated community. However, the ability of organisms to be phenotypically plastic allows them to rapidly adapt to changing environments and plasticity is commonly observed across all taxa. Owing to the fitness benefits of phenotypic plasticity, evolutionary biologists are interested in its genetic basis, which could explain how phenotypic plasticity is involved in the evolution of species interactions. Two current ideas exist: (i) phenotypic plasticity is caused by environmentally sensitive loci associated with a phenotype; (ii) phenotypic plasticity is caused by regulatory genes that simply influence the plasticity of a phenotype. Here, we designed a quantitative trait loci (QTL) mapping experiment to locate QTL on the barley genome associated with barley performance when the environment varies in the presence of aphids, and the composition of the rhizosphere. We simultaneously mapped aphid performance across variable rhizosphere environments. We mapped main effects, QTL 7 environment interaction (QTL 7E), and phenotypic plasticity (measured as the difference in mean trait values) for barley and aphid performance onto the barley genome using an interval mapping procedure. We found that QTL associated with phenotypic plasticity were co-located with main effect QTL and QTL 7E. We also located phenotypic plasticity QTL that were located separately from main effect QTL. These results support both of the current ideas of how phenotypic plasticity is genetically based and provide an initial insight into the functional genetic basis of how phenotypically plastic traits may still be important sources of community genetic effects

Manipulation of the calcium content of insectivore diets through supplementary dusting

Insects fed to captive insectivores are deficient in calcium with inverse calcium to phosphorous ratios (Ca:P), and supplementation is required to avoid nutritional metabolic bone disease (NMBD). One method of improving the nutritional value of feeder insects is by “dusting” with powdered supplements, although it is often suggested that these are rapidly shed from prey insects. Here we analysed the calcium content of hatchling, second, fourth and adult instars of black field crickets and silent crickets at increasing time intervals after dusting, as well as comparing three commercially available brands of supplement in fourth instar black field crickets. Our data show these brands do not differ from one another in terms of calcium delivery, despite differences in calcium content. We also show that dusting can be used to increase Ca:P ratios above 1:1 in crickets up to 5.5 hours after dusting, with the exception of adult black field crickets, and thus dusting is a useful method of calcium supplementation

Dichotomy of mangrove management: A review of research and policy in the Mesoamerican reef region.

Mangroves are declining globally at faster rates than tropical forests and coral reefs, with primary threats including, aquaculture, agriculture and climate change. Mangroves provide ecosystem services to coastal communities of Mexico, Belize, Guatemala and Honduras, which comprise the Mesoamerican Reef (MAR) ecoregion. Over the past two decades mangroves within the MAR have declined. Current estimates of mangrove cover in the region suggest that mangroves cover 239,176 ha of the MAR, equivalent to 1.7% of the world's mangroves. Concerted efforts to manage, conserve and protect mangrove forest are apparent in all four countries. Comprehensive laws that prohibit the cutting and clearing of mangroves have been implemented in Mexico, Guatemala and Honduras. Belize has a permitting system to regulate mangrove alterations. In addition, a total of seven international and regional agreements have been ratified. Across the ecoregion, forty-three protected areas have been designated that contain mangroves, providing protection to 111,396 ha of mangroves (47% of the total). However, our findings suggest a lack of transparency in the governance framework, a disconnect between management and research, and geopolitical differences have all played a role in reducing management efficacy. A key finding of our study reveals a distinct division in the perceived major threats to mangroves between Ramsar site managers and researchers. Ramsar site managers identify anthropogenic disturbances as key threats, while in contrast, the bulk of research focuses on natural disturbances. To promote the inclusion of evidencebased research within mangrove management plans, greater efforts to connect these important stakeholders are required

Female clustering in cockroach aggregations-A case of social niche construction?

© 2018 Blackwell Verlag GmbH. Individuals in groups can suffer costs through interactions with adversarial or unknown conspecifics. Social niche construction allows individuals to buffer such potential costs by only engaging in preferred associations. This may be particularly beneficial in insect aggregations, which are often large and highly fluid. However, little is known regarding the structuring of such aggregations. Here we use social network analyses to test for fine-scale social structure in resting aggregations of the sub-social cockroach Diploptera punctata and to explore the social pressures that contribute towards such structure. We showed that females were significantly more gregarious than males and formed the core of the proximity network, thus demonstrating a higher level of social integration. This fine-scale structure is likely to result from females displacing males; females initiated most displacements whilst males received the majority. We explain this behaviour in terms of social niche construction by showing that females received significantly fewer approaches and investigations at more female-biased local sex ratios. We therefore suggest that female social clustering occurs in this, and presumably other, species to reduce potential costs associated with male harassment. This demonstrates how social niche construction can lead to higher level social structure; we suggest this approach could be used across a range of species in order to improve our understanding of the evolution of sociality

Sex-biased parental care and sexual size dimorphism in a provisioning arthropod

The diverse selection pressures driving the evolution of sexual size dimorphism (SSD) have long been debated. While the balance between fecundity selection and sexual selection has received much attention, explanations based on sex-specific ecology have proven harder to test. In ectotherms, females are typically larger than males, and this is frequently thought to be because size constrains female fecundity more than it constrains male mating success. However, SSD could additionally reflect maternal care strategies. Under this hypothesis, females are relatively larger where reproduction requires greater maximum maternal effort – for example where mothers transport heavy provisions to nests. To test this hypothesis we focussed on digger wasps (Hymenoptera: Ammophilini), a relatively homogeneous group in which only females provision offspring. In some species, a single large prey item, up to 10 times the mother’s weight, must be carried to each burrow on foot; other species provide many small prey, each flown individually to the nest. We found more pronounced female-biased SSD in species where females carry single, heavy prey. More generally, SSD was negatively correlated with numbers of prey provided per offspring. Females provisioning multiple small items had longer wings and thoraxes, probably because smaller prey are carried in flight. Despite much theorising, few empirical studies have tested how sex-biased parental care can affect SSD. Our study reveals that such costs can be associated with the evolution of dimorphism, and this should be investigated in other clades where parental care costs differ between sexes and species

Genetically based adaptive trait shifts at an expanding mangrove range margin

AbstractNeotropical black mangrove (Avicennia germinans) is expanding poleward into temperate salt marsh along Atlantic Florida, USA, with field evidence of trait shifts consistent with greater cold tolerance within range margin populations. However, whether these shifts have a genetic basis remains unanswered. To address this gap, we measured multiple phenotypic traits of twenty A. germinans maternal cohorts from areas in both the Atlantic Florida range core and margin in a 2-year greenhouse common garden with annual temperatures analogous to range margin conditions. Compared to those from the range core, range margin cohorts survived in greater numbers, established (i.e., produced first true leaves) more quickly, and were less stressed under winter temperatures. Range margin cohorts were not taller, but invested more into lateral growth and biomass accumulation that presumably reflects adaptation to their colder and open-canopy environment. Range margin cohorts also exhibited leaf traits consistent with greater resource acquisition that may compensate for a shorter growing season and reduced light quality at higher latitude. Our results suggest that genetically based phenotypic differences better enable these range margin mangroves to thrive within their stressful environment and may facilitate further poleward expansion. An improved understanding of adaptive trait variation within ecologically important mangrove foundation species should also help inform coastal restoration initiatives.</jats:p

N availability, soil microbial biomass and β-glucosidase activity as influenced by the decomposition of nine plant residues during soil fertility improvement in Ghana

This study wasconducted to determine how the litter quality and decomposition of nine species (Acacia auriculiformis, Albizia zygia, Azadiractha indica,Baphia nitida, Gliricidia sepium, Leucaena leucocephala, Tithonia diversifolia, Senna spectabilis and Zea mays) influence soil N availability, microbial biomass and β-glucosidase activity during soil fertility improvement. The results on plant residue chemistry showed significant differences among species with N concentration ranging from 12.2 g kg−1 in Z. mays to 39.2 g kg−1 in B. nitida.C/N ratio was greatest in Z. mays (34.4) while lignin and polyphenol concentrations were greatest in A. auriculiformis. The highest decomposition rate (0.251% day−1) occurred in T. diversifolia and least in A. auriculiformis, A. zygia, B. nitida and Z. mays with half-lives of between 28 – 56 days. Similar to the results on decomposition, between 80 to 89% of N, P, K, Ca and Mg were released from T. diversifolia within 7 days compared with more than 70% retention in A. auriculiformis, B. nitida and Z. mays. Moreover, the half-lives of decomposition and nutrient release of G. sepium, L. leucocephala, A. indica and S. spectabiliswere within 14 days. Mineral N, soil microbial biomass and β-glucosidase activities increased in all treatments with T. diversifolia recording the greatest effect. While N mineralization occurred in all species throughout the experiment, an initial N immobilization was recorded in A. zygia, B. nitida, A. auriculiformis and Z. mays treatments for up to 14 days. Further, the results showed the decomposition, nutrient release rates, mineral N, soil microbial biomass and β-glucosidase activities were dependent on litter quality. Phosphorus, lignin, lignin/N ratio and (lignin + polyphenol)/N ratio were most influential based on significant (p = 0.05) results

Tagging frogs with passive integrated transponders causes disruption of the cutaneous bacterial community and proliferation of opportunistic fungi

Symbiotic bacterial communities play a key role in protecting amphibians from infectious diseases including chytridiomycosis,caused by the pathogenic fungus Batrachochytrium dendrobatidis. Events that lead to the disruption of the bacterial community may have implications for the susceptibility of amphibians to such diseases. Amphibians are often marked both in the wild and in captivity for a variety of reasons, and although existing literature indicates that marking techniques have few negative effects, the response of cutaneous microbial communities has not yet been investigated. Here we determine the effects of passive integrated transponder (PIT) tagging on culturable cutaneous microbial communities of captive Morelet’s tree frogs (Agalychnis moreletii) and assess the isolated bacterial strains for anti-B. dendrobatidis activity in vitro. We find that PIT tagging causes a major disruption to the bacterial community associated with the skin of frogs (∼12-fold increase in abundance), as well as a concurrent proliferation in resident fungi (up to ∼200-fold increase). Handling also caused a disruption the bacterial community, although to a lesser extent than PIT tagging. However, the effects of both tagging and handling were temporary, and after 2 weeks, the bacterial communities were similar to their original compositions. We also identify two bacterial strains that inhibit B. dendrobatidis, one of which increased in abundance on PIT-tagged frogs at 1 day postmarking, while the other was unaffected. These results show that PIT tagging has previously unobserved consequences for cutaneous microbial communities of frogs and may be particularly relevant for studies that intend to use PIT tagging to identify individuals involved in trials to develop probiotic treatments

Correction: A novel copro-diagnostic molecular method for qualitative detection and identification of parasitic nematodes in amphibians and reptiles (PLoS ONE (2017) 12: 9 (e0185151) DOI: 10.1371/journal.pone.0185151)

There is an error in the eighth sentence of the PCR amplification section. The correct sentence is: The degenerate nematode specific primers developed in this study (Nem27 primers) comprised Nem1217F which had the 5’-3’ sequence CGN BCC GRA CAC YGT RAG and Nem1619 which had the 5’-3’ sequence GGA AAY AAT TDC AAT TCC CKR TCC