Allozyme variation in populations of Bothrops asper (Serpentes: Viperidae in Costa Rica)

Artículo científico -- Universidad de Costa Rica, Instituto de Investigaciones en Salud. 1998We investigated allozyme variation from Costa Rican populations of the fer-de-lance, Bothrops asper. Blood samples were taken from a total of 100 specimens from six localities representing three major physiographic regions: Atlantic versant, Central Pacific lowlands, and Southwestern Pacific lowlands. Five of 16 protein coding loci (phosphogluconate mutase, isocitrate dehydrogenase, glucose 6-phosphate isomerase, malate dehydrogenase, and carbonic anhydrase-1) were polymorphic. Average heterozygosity for these loci varied between 2.9% and 5.5%. Genetic distances among samples from localities from the same physiographic region were not significantly different from zero. Pairwise comparisons between regions also resulted in low estimated distances. Analysis of population structure suggests high levels of gene flow among populations. Rates of evolution of venom and morphology previously reported for populations of this species seem to be uncoupled from rates of allozyme variation.En Costa Rica, gran diversidad en caracteres morfológicos, toxicológicos y de historia natural han sido previamente reportados entre poblaciones de la serpiente Bothrops asper. Con el fin de investigar la relación genética de esas diferencias, se evaluó la variación isozímica entre poblaciones de Bothrops asper en ese país. Se tomaron muestras de sangre de un total de 100 individuos provenientes de seis localidades representando a tres regiones fisiográficas: Vertiente Caribe, Pacífico Central y Pacífico Sur. De los 16 loci estudiados, cinco (Pgm-A, Icdh-A, Gpi-A, sMdh-A) resultaron polimórficos. El porcentaje de heterozigosis promedio por población varió entre 2.9 y 5.5%. Las distancias genéticas estimadas entre poblaciones fueron muy bajas. El análisis de la estructura génica indica que poblaciones de Bothrops asper en Costa Rica poseen alto flujo génico y gran homogeneidad genética entre ellas. Nuestros análisis sugieren evolución independiente entre los caracteres genéticos y fenotípicos observados en estas poblaciones. Se sugiere que la gran diversidad en veneno y morfologia en esta especie pueda estar asociada con diferencias de selección a nivel local.Universidad de Costa Rica, Instituto de Investigaciones en SaludUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Cannibalism by large tadpoles of Rhinophrynus dorsalis (Anura: Rhinophrynidae)

In June 2014, we captured approximately 100 R. dorsalis tadpoles in a net from a seasonal wetland in Palo Verde National Park (10.3428 N, 85.3375 W) in N, 85.3375 W) in northwestern Costa Rica. While rearing the tadpoles in the laboratory, we observed five events in which larger tadpoles (Stage 26; Gosner, 1960) fed on conspecifics at earlier stages. At first, we interpreted this behaviour as scavenging. However, after observing more closely during two subsequent events, we noticed that the predated individuals were still alive. We were not able to observe interactions with tadpoles in older stages at this time due to tadpole mortality. Then, during the first week of the rainy season (May to November annually) on 23 May 2018, we collected approximately 300 Rhinophrynus dorsalis tadpolesUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Development of Herpetoculture in Costa Rica: Current Situation of Herpetariums and Ex Situ Management of Reptiles and Amphibians

La tenencia de herpetofauna en cautiverio es una actividad que ha experimentado un enorme desarrollo en distintas partes del mundo, constituyéndose en la base de muchos programas de conservación, educación, e investigación. En Costa Rica, esta tendencia se evidencia en la proliferación de centros que mantienen reptiles y anfibios en las últimas dos décadas. Pese a este desarrollo, no hay disponible información centralizada sobre los herpetarios a nivel del país, por lo que se desconoce la forma como operan o los potenciales impactos que pudieran tener en la conservación de las especies mantenidas en ellos. En este trabajo se describen los centros que actualmente funcionan en el país, para lo cual se realizaron entrevistas a sus propietarios o regentes y visitas de conformación. Un total de 33 centros, que en conjunto albergan 144 especies, fueron encontrados. Este número de herpetarios resulta del desarrollo de la industria turística: la mayoría de ellos tienen como finalidad la exhibición de animales, aunque también algunos reportan fines educativos. Solo en cuatro centros se encontró clara evidencia de programas de investigación, pese a que la mayoría de herpetarios indicó la generación de conocimiento como uno de sus principales objetivos. Una proporción importante de establecimientos obtiene sus animales del medio, lo que supone un impacto en aquellas especies con poblaciones reducidas. Tal parece ser el caso de la matabuey Lachesis stenophrys, que se encontró en 66% de los centros, pese a ser una especie con poblaciones amenazadas en el país actualmente. La existencia de estos establecimientos demuestra el interés de nuestra sociedad por la tenencia de vida silvestre, y supone un interesante mosaico de experiencias, posibilidades y retos para la escena ambiental del país.The maintenance of reptiles and amphibians in captivity has greatly developed worldwide, becoming the basis of many conservation, education, and research programs. In Costa Rica, this trend is evident in the proliferation of centers that maintain herpetofauna in the last two decades. Despite this development, there is no information available on the centers existing in Costa Rica, and the way they operate, or the potential impacts they could have on the species kept remain unknown. In this study, we describe the facilities currently operating in the country, through a series of interviews to their owners or technical staff, and in situ observations. A total of 33 centers were found, which keep up to 144 species of reptiles and amphibians. This large number of facilities resulted from the development of the tourism industry in the country: most of them are intended to display animals, although some reported educational purposes. Most interviewed staff claims that generation of knowledge is one of the main objectives of their center. However, only four of them showed clear evidence of research programs. A significant percentage of centers get their animals directly from the natural environment, a practice that might have an impact on species with reduced populations in the wild. This seems to be the case of the Bushmaster Lachesis stenophrys, found in 66% of the centers, despite being a species that is nowadays threatened in the country. The existence of these facilities demonstrates the interest Costa Rica society has on wildlife, and it is an interesting mosaic of experiences, opportunities, and challenges for the environmental scene of the country.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP

Venom Composition and Diet of the Cantil Agkistrodon bilineatus howardgloydi (Serpentes: Viperidae)

The southernmost subspecies of the cantil, Agkistrodon bilineatus howardgloydi, occurs in almost all terrestrial habitats of the sector Santa Rosa National Park, in Guanacaste Conservation Area, Costa Rica. We obtained 21 specimens during several visits to the Park from 1983 to 1996. Neonates were observed only during late May through July, despite searching in other months, suggesting that birth in this subspecies occurs at the beginning of the rainy season. Fecal analyses revealed differences in diet composition between juveniles and adults. Juveniles prey primarily on lizards and various species of frogs, whereas adults, eat rodents. This ontogenetic change in diet does not seem to trigger any corresponding change in venom composition with snake age. Venom of this subspecies is highly toxic (LD50 = 1.25 æg/g), and has elevated hemorrhagic, hemolytic, and myotoxic activities. Extreme deforestation of dry forest habitats in the Pacific lowlands of Central America has made A. bilineatus a rare species over most of its range. Sector Santa Rosa in Costa Rica is the only area within its distributional range where the species still can be regularly observed.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP

Evidence of maternal provisioning of alkaloid-based chemical defenses in the strawberry poison frog Oophaga pumilio

Many organisms use chemical defenses to reduce predation risk. Aposematic dendrobatid frogs sequester alkaloid-based chemical defenses from a diet of arthropods, but research on these defenses has been limited to adults. Herein, we investigate chemical defense across development in a dendrobatid frog, Oophaga pumilio. This species displays complex parental care: at hatching, mothers transport tadpoles to phytotelmata, and then return to supply them with an obligate diet of nutritive eggs for about six weeks. We collected eggs, tadpoles, juveniles, and adults of O. pumilio, and detected alkaloids in all life stages. The quantity and number of alkaloids increased with frog and tadpole size. We did not detect alkaloids in the earliest stage of tadpoles, but alkaloids were detected as trace quantities in nutritive eggs and as small quantities in ovarian eggs. Tadpoles hand-reared with eggs of an alkaloid-free heterospecific frog did not contain alkaloids. Alkaloids that are sequestered from terrestrial arthropods were detected in both adults and phytotelm-dwelling tadpoles that feed solely on nutritive eggs, suggesting that this frog may be the first animal known to actively provision post-hatch offspring with chemical defenses. Finally, we provide experimental evidence that maternally derived alkaloids deter predation of tadpoles by a predatory arthropod.Ministerio del Ambiente, Energía y Technologia/[10CR000024]/MINAET/Costa RicaThe Convention on International Trade in Endangered Species/[10CR000024]/CITES/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP

Mutual enlightenment: A toolbox of concepts and methods for integrating evolutionary and clinical toxinology via snake venomics and the contextual stance

Snakebite envenoming is a neglected tropical disease that may claim over 100,000 human lives annually worldwide. Snakebite occurs as the result of an interaction between a human and a snake that elicits either a defensive response from the snake or, more rarely, a feeding response as the result of mistaken identity. Snakebite envenoming is therefore a biological and, more specifically, an ecological problem. Snake venom itself is often described as a “cocktail”, as it is a heterogenous mixture of molecules including the toxins (which are typically proteinaceous) responsible for the pathophysiological consequences of envenoming. The primary function of venom in snake ecology is pre-subjugation, with defensive deployment of the secretion typically considered a secondary function. The particular composition of any given venom cocktail is shaped by evolutionary forces that include phylogenetic constraints associated with the snake’s lineage and adaptive responses to the snake’s ecological context, including the taxa it preys upon and by which it is predated upon. In the present article, we describe how conceptual frameworks from ecology and evolutionary biology can enter into a mutually enlightening relationship with clinical toxinology by enabling the consideration of snakebite envenoming from an “ecological stance”. We detail the insights that may emerge from such a perspective and highlight the ways in which the high-fidelity descriptive knowledge emerging from applications of -omics era technologies – “venomics” and “antivenomics” – can combine with evolutionary explanations to deliver a detailed understanding of this multifactorial health crisis.Ministerio de Ciencia e Innovacion/[BMC 2004-01432]//EspañaMinisterio de Ciencia e Innovacion/[BFU 2007-61563]//EspañaMinisterio de Ciencia e Innovacion/[BFU 2010-173730]//EspañaMinisterio de Ciencia e Innovacion/[BFU 2013-42833-P]//EspañaMinisterio de Ciencia e Innovacion/[BFU 2017-89103-P]//EspañaNorwegian Research Council/[No.287462.]/NFR/NoruegaNational Health and Medical Research Council/[Grant 13/093/002 AVRU]/AustraliaDBT/Wellcome Trust India Alliance/[IA/I/19/2/504647]//IndiaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP

Integrated “omics” profiling indicates that miRNAs are modulators of the ontogenetic venom composition shift in the Central American rattlesnake, Crotalus simus simus

Background Understanding the processes that drive the evolution of snake venom is a topic of great research interest in molecular and evolutionary toxinology. Recent studies suggest that ontogenetic changes in venom composition are genetically controlled rather than environmentally induced. However, the molecular mechanisms underlying these changes remain elusive. Here we have explored the basis and level of regulation of the ontogenetic shift in the venom composition of the Central American rattlesnake, Crotalus s. simus using a combined proteomics and transcriptomics approach. Results Proteomic analysis showed that the ontogenetic shift in the venom composition of C. s. simus is essentially characterized by a gradual reduction in the expression of serine proteinases and PLA2 molecules, particularly crotoxin, a β-neurotoxic heterodimeric PLA2, concominantly with an increment of PI and PIII metalloproteinases at age 9–18 months. Comparison of the transcriptional activity of the venom glands of neonate and adult C. s. simus specimens indicated that their transcriptomes exhibit indistinguisable toxin family profiles, suggesting that the elusive mechanism by which shared transcriptomes generate divergent venom phenotypes may operate post-transcriptionally. Specifically, miRNAs with frequency count of 1000 or greater exhibited an uneven distribution between the newborn and adult datasets. Of note, 590 copies of a miRNA targeting crotoxin B-subunit was exclusively found in the transcriptome of the adult snake, whereas 1185 copies of a miRNA complementary to a PIII-SVMP mRNA was uniquely present in the newborn dataset. These results support the view that age-dependent changes in the concentration of miRNA modulating the transition from a crotoxin-rich to a SVMP-rich venom from birth through adulhood can potentially explain what is observed in the proteomic analysis of the ontogenetic changes in the venom composition of C. s. simus. Conclusions Existing snake venom toxins are the result of early recruitment events in the Toxicofera clade of reptiles by which ordinary genes were duplicated, and the new genes selectively expressed in the venom gland and amplified to multigene families with extensive neofunctionalization throughout the approximately 112–125 million years of ophidian evolution. Our findings support the view that understanding the phenotypic diversity of snake venoms requires a deep knowledge of the mechanisms regulating the transcriptional and translational activity of the venom gland. Our results suggest a functional role for miRNAs. The impact of specific miRNAs in the modulation of venom composition, and the integration of the mechanisms responsible for the generation of these miRNAs in the evolutionary landscape of the snake's venom gland, are further challenges for future research.Ministerio de Economía y Competitividad/[BFU2010-17373]//EspañaGeneralitat Valenciana/[PROMETEO/2010/005]//EspañaUniversidad de Costa Rica/[741-B2-093]/UCR/Costa Rica/2009CR0021/CRUSA-CSIC/EspáñaPrograma Iberoamericano de Ciencia y Tecnología para el Desarrollo/206AC0281/CYTED/EspañaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP

Distribution and reprodudion of tbe gray earth snake Geophis brachycephalus (Serpentes: Colubridae) in Costa Rica

En Costa Rica, el colúbrido excavador Geophis brachycephalus se distribuye principalmente en tierras altas del Sistema Montañoso Central. Se presentan las primeras observaciones en tamaño de nidada, incubación y medidas de neonatos de la especie. La actividad reproductiva no es estacional, lo que podría deberse a un fenómeno de asincronía reproductiva o a múltiples nidadas por año. El tamaño promedio de cada nidada es de 4.2 huevos que miden 24.88 ±2.25 X 9 .94 ± 0.2 mm. Los neonatos poseen un collar nucal característico que se pierde ontogénicamente.En Costa Rica, el colúbrido excavador Geophis brachycephalus se distribuye principalmente en tierras altas del Sistema Montañoso Central. Se presentan las primeras observaciones en tamaño de nidada, incubación y medidas de neonatos de la especie. La actividad reproductiva no es estacional, lo que podría deberse a un fenómeno de asincronía reproductiva o a múltiples nidadas por año. El tamaño promedio de cada nidada es de 4.2 huevos que miden 24.88 ±2.25 X 9 .94 ± 0.2 mm. Los neonatos poseen un collar nucal característico que se pierde ontogénicamente

Morphological variation in the lancehead pitviper Bothrops asper (Garman) (Serpentes: Viperidae) from Middle America

Variation of morphological characters in the pitviper Bothrops asper (Garman) was studied in terms of scutellation, color patterns, and landmark measures for 374 Middle American specimens. Gender, ontogeny, and geographic effects were examined for each character. In this species, females are larger than males and have more ventral and dorsal rows, and can be distinguished by some landmark variables. Males have a higher number of subcaudals and usually are more heavily pigmented in the supralabial region. Age does not affect scutellation, although it does influence pigmentation patterns. Geographic differences were evident in several traits. The seven Middle American populations included in these analyses can be clustered in two major groups: those from Mexico and Nuclear Central America and those from Isthmian Central America. Distinction between these groups is possible in terms of univariate statistics and differences are explained in terms of population fragmentation due to the dynamics of rainforest during Quaternary or by isolation by distance among populations within each region.La variación morfológica de Bothrops asper fue estudiada en 374 especímenes mesoamericanos en términos de escamación, patrones de coloración y medidas corporales. El efecto de sexo, ontogenia y geografía fue examinado para cada carácter. Se observó dimorfismo sexual en varios caracteres: las hembras son más largas y poseen más filas de escamas dorsales y ventrales, pudiéndoseles distinguir además a partir de otras medidas corporales. Los machos poseen un mayor número de subcaudales y están más fuertemente pigmentados en la región supralabial. El patrón de escamación no es afectado por la edad, aunque esta sí influye en los patrones de pigmentación. Basado en las diferencias observadas en caracteres morfológicos, las siete poblaciones de B. asper incluídas en este análisis pueden ser agrupadas en dos regiones: aquellas provenientes de México y Centroamérica Nuclear y las incluídas en Centroámerica Istmica. La distinción entre estos grupos es posible mediante análisis univariable y son explicadas en términos de fragmentación de población debido al desarrollo de los bosques lluviosos en la región o al aislamiento por distancia entre poblaciones incluídas en cada regió

PREFACIO Yolillales, los humedales olvidados

La destrucción acelerada de la cobertura boscosa y la indiscriminada explotación de los recursos naturales son, sin duda, los principales problemas que enfrenta la diversidad biológica del planeta. Como resultado del explosivo incremento demográfico de la población humana y del aumento significativo en su consumo de recursos, cada vez es más difícil encontrar ecosistemas relativamente inalterados, donde el patrimonio biológico pueda mantenerse y las funciones ecológicas desarrollarse sin intervención. Sumado a estos factores, el cambio climático global –y sus consecuencias a nivel local– juegan un papel cada vez más preponderante en la alteración de recursos biológicos y la reducción de biodiversidad.La destrucción acelerada de la cobertura boscosa y la indiscriminada explotación de los recursos naturales son, sin duda, los principales problemas que enfrenta la diversidad biológica del planeta. Como resultado del explosivo incremento demográfico de la población humana y del aumento significativo en su consumo de recursos, cada vez es más difícil encontrar ecosistemas relativamente inalterados, donde el patrimonio biológico pueda mantenerse y las funciones ecológicas desarrollarse sin intervención. Sumado a estos factores, el cambio climático global –y sus consecuencias a nivel local– juegan un papel cada vez más preponderante en la alteración de recursos biológicos y la reducción de biodiversidad.