The functions of secreted animal mucuses are remarkably diverse and include lubricants, wet adhesives, protective barriers, and mineralizing agents. Although present in all animals, many open questions related to the hierarchical architectures, material properties, and genetics of mucus remain. Here, we summarize what is known about secreted mucus structure, describe the work of research groups throughout the world who are investigating various animal mucuses, and relate how these studies are revealing new mucus properties and the relationships between mucus hierarchical structure and hydrogel function. Finally, we call for a more systematic approach to studying animal mucuses so that data sets can be compared, omics-style, to address unanswered questions in the emerging field of mucomics. One major result that we anticipate from these efforts is design rules for creating new materials that are inspired by the structures and functions of animal mucuses.

Abstract:Little is known about how restoration strategies affect aspects like leaf litter's quantity, depth and humidity. I analyzed leaf litter's quantity, depth and humidity yearly patterns in a primary tropical lower montane wet forest and two restored areas: a 15 year old secondary forest (unassisted restoration) and a 40 year old Cupressus lusitanica plantation (natural understory). The three habitats are located in the Río Macho Forest Reserve, Costa Rica. Twenty litter samples were taken every three months (April 2009-April 2010 in each habitat; humidity was measured in 439g samples (average), depth and quantity were measured in five points inside 50x50cm plots. None of the restoration strategies reproduced the primary forest leaf litter humidity, depth and quantity yearly patterns. Primary forest leaf litter humidity was higher and more stable ( =73.2), followed by secondary forest ( =63.3) and cypress plantation ( =52.9) (Kruskall-Wallis=77.93, n=232, p=0.00). In the primary (Kruskal-Wallis=31.63, n=78, p<0.001) and secondary (Kruskal-Wallis=11.79, n=75, p=0.008) forest litter accumulation was higher during April due to strong winds. In the primary forest (Kruskal-wallis=21.83, n=78, p<0.001) and the cypress plantation (Kruskal-wallis=39.99, n=80, p<0.001) leaf litter depth was shallow in October because heavy rains compacted it. Depth patterns were different from quantity patterns and described the leaf litter's structure in different ecosystems though the year. Rev. Biol. Trop. 60 (3):

Abstract. Introduction: Ecology and natural history of neotropical land snails is almost unknown. Objetive: In this paper I analyse the population dynamics of Tikoconus (Tikoconus) costarricanus Barrientos, in prep., an understory endemic euconulid. Methods: I compared T. costarricanus’ demography patterns in tropical montane forests in central Costa Rica in three habitats with different restoration techniques: a mature forest, a secondary forest and a Cuppressus lusitanica plantation. I collected data in three month periods during a year. I analysed population size in relation with habitat, sampling date, leaf litter humidity, depth and quantity; and specimen size in relation with habitat and sampling date. I also kept some specimens in terraria and described part of their natural history. Results: The species is more abundant in mature forest (Ø = 0.174 ind/m2). The number of specimens in each habitat was constant throughout the year (Kruskall-Wallis = 2.0118, p = 0.57, NS) and hatching occurs in the middle and last months of the rainy season (Kruskall-Wallis = 17.3061, p = 0.00061, **). Number of specimens is related with leaf litter humidity (Spearman correlation, r = 0.3524, n = 232, p = 0.000, **), amount (Spearman correlation, r = 0.3922, n = 232, p = 0.000, **) and depth (Spearman correlation, r = 0.2543, n = 232, p = 0.000, **). This relationship is explained by the high and stable humid environment provided by leaf litter. During the drier months some specimens migrate from the foliage to the leaf litter. Eggs (Ø = 1mm) are laid on moss or soil and the young spend the first 2 or 3 weeks of their life on moss. Egg masses are small (Ø = 4 eggs), and shells look bubbly. Egg development time (20 days) was longer than in other tropical species. Adult pigmentation appears around two months after hatch. In the only case observed egg laying began 5 months after hatching and the specimen lived 9 months. Conclusions: Although no conclusive, these data point to a fragile species susceptible to habitat and climate change. Restorations techniques should consider leaf litter features in order to protect endemic neotropical humid dependent diversity.

Introduction: Many land molluscs survival strategies are still poorly understood or have not been even reported, especially in the Neotropics. Methods: I collected 25 adult Tikoconus (Tikoconus) costarricanus from Reserva Forestal Río Macho, Costa Rica. I kept the specimens for 8 days in terrariums to film their behavior. Objective: To analyse the behavior of T. costarricanus, with emphasis on its strategies to survive drought and probably also predation. Results: This snail has at least three unusual behaviors that probably help them reduce dehydration and may be escape from enemies and avoid diseases: hanging upside down like bats, falling and grooming. During aestivation, they compress the body and hang upside down from leaves, like bats hang from perches. They attach to the underside of leaves with mucus from a caudal gland. Disengagement is done with vigorous shell rotations and foot twisting in contorting sequences, and can be done as reaction to direct sunlight, and probably to avoid predators and parasites. They groom their own shell, shell lappets and foot, an unusual behavior among land snails. This species feeds mainly on epiphyllous mosses, algae and lichens, occasionally adding arthropod eggs and carrion. Egg laying is similar to other euconulids and valloniid snails. Conclusions: Aestivating hanging upside down is a drought avoiding trait described here for the first time and is also a new function for the caudal gland mucus. Leaf detaching is done by a contortion sequence of shell rotations and foot twisting; its complexity and duration varies according to the leaf side where the snail is located.

Un género nuevo de semibabosas (Stylommatophora: Euconulidae) de Costa Rica y revisión del género Velifera (Stylommatophora: Euconulidae). La familia Econulidae tiene distribución circumglobal, pero solo la subfamilia Euconulinae está presente en el continente americano. En Costa Rica hay reportadas 14 especies nativas de euconúlidos. En este trabajo describo el género Tikoconus g.n., un euconúlido nuevo y endémico de Costa Rica. Este género se puede reconocer por su aspecto de semibabosa, su concha externa subglobosa a subglobosa comprimida, muy delgada y flexible. La ausencia de pequeños puntos negros en el manto y la presencia de al menos algunas manchas oscuras en la banda inferior del surco pedal, junto con una prolongación en forma de Z de la uretra que casi alcanza el collar del manto, son distintivos del género. El sistema reproductivo tiene una glándula penial distintiva. Ésta, tiene forma de C, rodea el pene, está adherida al pene y al ciego del pene, pero carece de ductos conectores y tiene una extensión interna en el pene mono o bilobulada. El epifalo tiene una verga que ingresa en el pene. La caperuza del pene rodea parte del pene, la base del epifalo y la inserción del músculo retractor del pene, deja libre la glándula penial y el ciego del pene. Carece de glándula gametolítica. Describo dos subgéneros nuevos: Tikoconus sensu stricto con 6 especies T. (T.) costaricanus sp.n. (type species), T. (T.) onca sp.n., T. (T.) andresi sp.n., T. (T.) katyae sp.n., T. (T.) alosii sp.n., T. (T.) subsilvanus sp.n.; y Bribriconus con una especie T. (B.) thompsoni sp.n. Todas las especies tienen una distribución restringida a una cuenca, la única excepción es T. costaricanus que vive en casi todas las cadenas montañosas de Costa Rica. Este género habita en bosques tropicales muy húmedos y poco alterados de los 400 a los 2 500 masl en la vertiente atlántica y de los 760 a los 2 500 masl en la vertiente pacífica. El género Velifera, la otra semibabosa euconúlida reportada para Costa Rica, se mantiene como un taxón válido. Escojo el espécimen ANSP 48765 como lectotipo de Velifera gabbi con el propósito de aclarar la aplicación del nombre a un taxón.

Durante 16 meses se estudió en laboratorio la biología básica de Ovachlamys fulgens en Costa Rica. Esta especie se reprodujo sin copular (N= 40) Y su longevidad fue de nueve meses (N= 22). La oviposición inició a los 42 días de haber eclosionado y con 5.12 mm de diámetro de concha (N= 24). Los huevos fueron depositados en camadas diarias de alrededor de tres huevos (N= 252). Existe una correlación positiva entre la edad y el diámetro de la concha del progenitor y el tamaño de la camada (N= 1097), y entre el diámetro de los huevos y el de la concha de adultos y neo natos (N= 136). Los huevos de cáscara suave son depositados semi-hidratados y se hidratan absorbiendo agua del entorno (N= 21). Esta estrategia puede ser el resultado evolutivo entre una limitación mecánica (pequeño tamaño corporal) y la ventaja de producir huevos más grandes con más sustancias nutritivas. Los huevos tardan 14 días en eclosionar a 21°C- (N= 67). La disolución de la cáscara del huevo no es uniforme (N= 107), sino que comienza en un área específica, que normalmente es en la que reposa (N=46). El hecho de que huevos sin embrión (N= 5) pasen por el mismo proceso de disolusión de la cáscara sugiere que éste es de carácter químico. El embrión no induce el proceso, pero si lo acelera. Los taninos de la hojarasca que rodea los huevos reduce su viabilidad (N= 50).

Terrestrial mollusks (Mollusca: Gastropoda) of Costa Rica: classification, distribution and conservation. Terrestrial mollusks are poorly known worldwide. The country has 183 reported species, 30% endemic and 7% are probably extinct. About 400 species are expected to inhabit the country. Biology, ecology, distribution, genetics and other areas of research are unknown for more than 95% of the species. The most diverse families are Spiraxidae, Orthalicidae and Subulinidae. However, the family that may have more species is Euconulidae. Euconulids inhabit the highlands, where less work has been done. The study of species of highlands will also rise the endemism rate. Future taxonomic, biological and ecological work should consider their low vagility, tendency to produce new taxa in sympatry, specific microhabitat requirements, hermaphroditism, high evolutionary rate (10% per million years), and divergence between species (2 to 30%). Urgent studies to protect the Costa Rican malacofauna include: distribution, abundance, effect of land use and climate changes on populations. Rev. Biol. Trop. 58 (4): 1165-1175. Epub 2010 December 01.

Student attrition in posgraduate blended programs at the Universidad Estatal a Distancia (UNED), Costa Rica: Desertion or delay?Postgraduate student attrition in blended (traditional and distance) education programs has been little studied. Several theoretical categories have been developed to justify attrition: psychological, academic, sociological, economic, organizational, supply and demand of higher education and the market, and interaction. Through surveys, interviews and institutional data the case of a blended learning academic master program is analyzed. It was found that the problem must be rethought as a delay in graduation (68%). Desertion calculated according to academic regulations is 87%, but according to the intention expressed by the students is 19%, of which 6% transfer to other institutions. Besides this, it takes on average 16 months to submit the candidacy exam although by regulations it is expected to do so in 6 months. Therefore, applying appropriate strategies may lower the dropout rate to about 15%. Desertion (as intention expressed by the students) is negatively correlated with their opinion about: 1) degree of concordance between the career`s output profile and the labor market needs, 2) teachers teaching skills and 3) relationship between the work performed by the student and the master programm. None of the existing theoretical categories fully explain the results, so it is considered that the determining factors in the dropout may vary by sociocultural and institutional situation of each case. To reduce dropout improvements must be made in: 1) teaching skills, 2) curriculum, 3) students selection, 4) subject´s contents of the first block, 5) admission of undergraduate students from the same institution and 7) induction to a blended learning system. To reduce delays in graduation people in charge must: 1) restructure the seminary courses, 2) strengthen research in the courses, 3) give more supervision and assistance to student`s research project, 4) fit regulation times to students that work full time and 5) select students who really want an academic program (not a professional program). KEY WORDSPostgraduate student attrition, delayed graduation, student retention, higher education dropouts. RESUMENLa deserción estudiantil para posgrados semipresenciales ha sido poco estudiada. Se han desarrollado varias categorías teóricas para justificar la deserción: psicológica, académica personal, sociológica, económica, organizacional, oferta y demanda de la educación superior y del mercado, e interacción. Mediante encuestas, entrevistas y datos institucionales se analiza el caso de una maestría académica semipresencial. Se encontró que el problema debe repensarse como un retraso en la graduación (68%), pues la deserción calculada según el reglamento académico es del 87%, pero según la intención expresada por los estudiantes es de 19%, de los cuales el 6% corresponde a traslados a otras instituciones, además, en promedio tardan 16 meses en presentar el examen de candidatura cuando reg...