Sand-swimming behaviour reduces ectoparasitism in an iguanian lizard.

Sand swimming behaviour occurs in several lizard clades. Known ecological advantages of sand swimming include reduced predation risk and enhanced thermoregulation. We addressed whether, by way of sand abrasion, sand-swimming reduces ectoparasitism in the lizard Microlophus occipitalis, whose natural habitat includes sandy substrates (beach) and firm soil (dry forest). We hypothesised that, aside from habitat differences in infestation probability, ectoparasite prevalence and load would be lower in the beach than in the forest because of ectoparasite removal caused by sand-swimming. In an experiment with lizards confined in boxes with substrate from both habitats, lizards in beach boxes showed a greater decrease in ectoparasite load compared with lizards in forest boxes. Ectoparasite prevalence and load were much higher in the forest than in the beach across seasons. Larger lizards showed higher ectoparasite loads, and there were no sex differences in ectoparasite infestation. We provide evidence that sand swimming may confer another ecological advantage to lizards: reduced ectoparasitism.

Local host adaptation and use of a novel host in the seed beetle Megacerus eulophus.

Spatial variation in host plant availability may lead to specialization in host use and local host adaptation in herbivorous insects, which may involve a cost in performance on other hosts. We studied two geographically separated populations of the seed beetle Megacerus eulophus (Coleoptera: Bruchidae) in central Chile: a population from the host Convolvulus chilensis (in Aucó) and a population from C. bonariensis (in Algarrobo). In Aucó C. chilensis is the only host plant, while in Algarrobo both C. bonariensis and C. chilensis are available. We tested local adaptation to these native host plants and its influence on the use of another, exotic host plant. We hypothesized that local adaptation would be verified, particularly for the one-host population (Aucó), and that the Aucó population would be less able to use an alternative, high-quality host. We found evidence of local adaptation in the population from C. chilensis. Thus, when reared on C. chilensis, adults from the C. chilensis population were larger and lived longer than individuals from the C. bonariensis population, while bruchids from the two populations had the same body size and longevity when reared on C. bonariensis. Overall, bruchids from the C. chilensis population showed greater performance traits than those from the C. bonariensis population. There were no differences between the bruchid populations in their ability to use the alternative, exotic host Calystegia sepium, as shown by body size and longevity patterns. Results suggest that differences in local adaptation might be explained by differential host availability in the study populations.

Community impacts of Prosopis juliflora invasion: biogeographic and congeneric comparisons.

We coordinated biogeographical comparisons of the impacts of an exotic invasive tree in its native and non-native ranges with a congeneric comparison in the non-native range. Prosopis juliflora is taxonomically complicated and with P. pallida forms the P. juliflora complex. Thus we sampled P. juliflora in its native Venezuela, and also located two field sites in Peru, the native range of Prosopis pallida. Canopies of Prosopis juliflora, a native of the New World but an invader in many other regions, had facilitative effects on the diversity of other species in its native Venezuela, and P. pallida had both negative and positive effects depending on the year, (overall neutral effects) in its native Peru. However, in India and Hawaii, USA, where P. juliflora is an aggressive invader, canopy effects were consistently and strongly negative on species richness. Prosopis cineraria, a native to India, had much weaker effects on species richness in India than P. juliflora. We carried out multiple congeneric comparisons between P. juliflora and P. cineraria, and found that soil from the rhizosphere of P. juliflora had higher extractable phosphorus, soluble salts and total phenolics than P. cineraria rhizosphere soils. Experimentally applied P. juliflora litter caused far greater mortality of native Indian species than litter from P. cineraria. Prosopis juliflora leaf leachate had neutral to negative effects on root growth of three common crop species of north-west India whereas P. cineraria leaf leachate had positive effects. Prosopis juliflora leaf leachate also had higher concentrations of total phenolics and L-tryptophan than P. cineraria, suggesting a potential allelopathic mechanism for the congeneric differences. Our results also suggest the possibility of regional evolutionary trajectories among competitors and that recent mixing of species from different trajectories has the potential to disrupt evolved interactions among native species.

Chemical composition of Apodanthera biflora, a Cucurbit of the dry forest in northwestern Peru

The dry forest of northwestern Peru is the habitat of numerous native species that have received little attention beyond taxonomic purposes. Here we report the chemical composition of the roots and seeds of a set of accessions of Apondanthera biflora, a wild Cucurbit with potentialities as a food resource. The roots show features that are comparable to those from cassava roots and potato tubers: a high content of carbohydrates on a dry matter basis (77.5 - 84.9%), with starch representing around 20% of the total dry matter. The seeds fat content on a dry matter basis (22.22 - 39.37%) falls within the percentages found in oily seeds such as safflower, whereas the protein content (21.37 - 29.06%) is similar to that of flax and sunflower. The fatty acid profile of the seeds oil shows a predominance of polyunsaturated acids, in particular linoleic acid (43.81%), making it comparable to that of cotton oil. Our results confirm the nutritional value of Apodanthera biflora and set the ground for its use in domestication and food security programs.

El bosque seco del noroeste del Perú es hábitat de numerosas especies nativas que, fuera de su taxonomía, han sido poco estudiadas. En este trabajo se reporta la composición química de las raíces y semillas de un grupo de accesiones de Apodanthera biflora, una cucurbitácea silvestre con potencial nutricional. Las raíces muestran una composición comparable a la de la yuca y la papa: un alto contenido de carbohidratos en base al peso seco (77,5 - 84,9%), entre los cuales destaca el almidón con alrededor de 20% del peso seco. El contenido de grasas de la semilla en base al peso seco (22,22 - 39,37%) está dentro del rango descrito en semillas oleaginosas como las de cártamo, mientras que el contenido de proteínas (21,37 -29,06%) es similar al hallado en semillas de lino y girasol. En el perfil de ácidos grasos del aceite de la semilla se observa un predominio de los ácidos grasos poliinsaturados, en particular del ácido linoleico (43,81%), que lo hace comparable al del aceite de algodón. Los resultados confirman el valor nutricional de Apodanthera biflora y sienta las bases para su domesticación y aprovechamiento en programas de seguridad alimentaria.

Optimización de los medios de propagación y enraizamiento in vitro de las variedades “criollas” de vid para elaborar pisco / Optimization of media for in vitro propagation and rooting of creole

Los protocolos y medios disponibles para la propagación y enraizamiento in vitro de la vid no han sido ajustados todavía a las variedades “criollas” con las que se elabora el pisco. En este trabajo se exploró el uso de medios para la propagación de las variedades Quebranta, Negra Criolla, Albilla, Italia y Torontel, así como para el enraizamiento de las variedades Quebranta, Albilla y Torontel, a partir de los medios estándares reportados en la literatura científica. Para ello, se pusieron a prueba 11 variantes del medio estándar de propagación de vid (medio Murashige y Skoog 1X, 3% de sucrosa, 1 mg/L de benzilaminopurina y 0,8% de agar) en las que se combinaron reducciones en la fuerza del medio con reducciones en la concentración de hormona. Para el enraizamiento posterior, se probaron el ácido naftalen acético y el ácido indol acético a 5 concentraciones distintas por cada hormona. Los resultados mostraron que el mejor medio para la propagación de las variedades Quebranta, Albilla e Italia es el estándar; las variedades Negra Criolla y Torontel tuvieron mejor desempeño con una reducción de la concentración de benzilaminopurina a 0,25 y 0,5 mg/L, respectivamente. El mejor enraizamiento en la variedad Quebranta ocurrió con 80 µg/L de ácido naftalen acético y 2 mg/L de ácido indol acético; las variedades Albilla y Torontel tuvieron una mejor respuesta al ácido indol acético a concentraciones de 2 y 1 mg/L, respectivamente.

The protocols and culture media available for in vitro propagation and rooting of grapevine have not yet been adjusted to the creole varieties used for pisco making. In this paper we explored the use of culture media for the propagation of varieties Quebranta, Negra Criolla, Albilla, Italia and Torontel and for rooting varieties of Quebranta, Albilla and Torontel based on known standard culture media.To address this issue, 11 media derived from the standard propagation medium for grapevine (1X Murashige & Skoog medium, 3% sucrose, 1 mg/L benzilaminopurine, and 0,8% agar) with diminished medium strength and/or hormone concentration were tested. In addition, 5 concentrations of naphtalen acetic acid or indol acetic acid were tested for rooting. We found that Quebranta, Albilla, and Italia varieties show a better growth in the standard propagation medium; by contrast, Negra Criolla and Torontel grew better in media with diminished benzilaminopurine concentrations (0,25 and 0,5 mg/L, respectively). Quebranta rooted better with 80 µg/L naphtalen acetic acid or 2 mg/L indol acetic acid, while Albilla and Torontel showed better rooting results with 2 and 1 mg/L indol acetic acid, respectively.

A new species of Uroleucon (Hemiptera: Aphididae) on Madia (Asteraceae) in Chile

Uroleucon is one of very few aphid genera that have species indigenous to South America. A new species of aphid from Chile is described and illustrated, Uroleucon eumadiae sp. nov., living on the two South American species of the genus Madia (Asteraceae): M. sativa Mol. and M. chilensis (Nutt.) Reiche. Morphological characters are discussed and the characters by which this aphid species may be distinguished from related ones are given. The long, hairy last rostral segment of the new species suggests strongly a feeding adaptation, and parallels that of a North American Madia-feeding species in the same genus which is not, however, closely related.

Uroleucon é um dos poucos gêneros de afídeos com espécies nativas da América do Sul. Neste trabalho, é descrita e ilustrada uma nova espécie do Chile, Uroleucon eumadiae sp. nov., coletada em duas espécies sul-americanas do gênero Madia (Asteraceae): M. sativa Mol. e M. chilensis (Nutt.) Reiche. São discutidos os caracteres morfológicos e aqueles utilizados para distinguir U. eumadiae de outras espécies relacionadas. O ultimo segmento rostral piloso desta espécie sugere uma adaptação alimentar, paralela a uma outra espécie que ocorre na América do Norte e que também se alimenta de plantas de do gênero Madia, mas que não é filogeneticamente próxima.