RESUMO

Abstract: The tropical dry forest is under constant threat from many anthropic activities which are conducted indiscriminately, modifying the forest, and therefore, affecting species that are closely related to its phenology, such as longhorned beetles (Cerambycidae). The spatio-temporal variation of the cerambycid diversity in two fragments of tropical dry forest (Reserva Campesina la Montaña and La Flecha) in the Caribbean region of Colombia was analyzed. At each locality, four squared plots were delimited, and the beetles were collected with fruit traps, beating sheets and manual capture, and with light traps in the center. Five hundred eighty-seven specimens representing 128 species were collected, of which members of the tribe Ectenessini (Cerambycinae) were the most abundant. At the subfamily level, Cerambycinae was the most abundant (465 specimens) and diverse (73 species), followed by Lamiinae and Prioninae. The highest values of richness (110 species), abundance (428), biomass (21.18 g), and as well as the highest values of true diversity (1D= 73.44, 2D= 34.30) were found during the first precipitations. Regarding beta diversity, temporal variation was determined and mainly explained by a high percentage of turnover (> 70%). Lastly, the high diversity of Cerambycidae was associated with high values of relative humidity and canopy cover during the rainy season. This showed that the structure of the cerambycid community in the tropical dry forest of the Caribbean region of Colombia depends on these variables, which are closely related to precipitation.

Resumo: A floresta seca tropical está sob constante ameaça devido às muitas atividades antrópicas que são realizadas indiscriminadamente, modificando a floresta e, portanto, afetando espécies que se encontram muito relacionadas com a sua fenologia, tais como os besouros serra-pau (Cerambycidae). Foi analisada a variação espaço-temporal da diversidade de cerambícidos em dois fragmentos de floresta seca tropical ("Reserva campesina La Montaña e La Flecha") na região caribenha da Colômbia. Em cada localidade, quatro quadrantes foram delimitados e os besouros foram coletados usando armadilhas com isca de fruta, guarda-chuva entomológico, captura manual e armadilhas de luz. Quinhentos e oitenta e sete espécimes, de 128 espécies foram coletados, sendo os membros da tribo Ectenessini (Cerambycinae) os mais abundantes. Ao nível de subfamília, Cerambycinae foi a mais abundante (465 espécimes) e diversa (73 espécies), seguida de Lamiinae e Prioninae. Os valores mais altos de riqueza (110 espécies), abundância (428) e biomassa (21.18 g) foram encontrados durante as primeiras chuvas, assim como os valores mais altos de diversidade verdadeira (1D= 73.44, 2D= 34.30). Em relação à diversidade beta, a variação temporal foi determinada e principalmente explicada por uma alta porcentagem de substituição (> 70%). Por último, uma alta diversidade de Cerambycidae foi associada com altos valores de humidade relativa e cobertura vegetal durante a temporada de chuva, mostrando que a estrutura da comunidade de Cerambycidae na floresta seca tropical da Colômbia depende dessas variáveis, as quais são muito relacionadas com a precipitação.

RESUMO

Five new species of the ghost spider genus Anyphaenoides Berland from Colombia are described and illustrated: A. sierraensis sp. nov. (based on male and female) from Magdalena department, A. caribensis sp. nov. (male and female) from Atlántico department, A. foreroi sp. nov. (male) from Vaupes department, A. hilli sp. nov. (male) from Putumayo department and A. enigmaticus sp. nov. (male and female) from Santander department.

Assuntos

RESUMO

Five new species of the ghost spider genus Anyphaenoides Berland from Colombia are described and illustrated: A. sierraensis sp. nov. (based on male and female) from Magdalena department, A. caribensis sp. nov. (male and female) from Atlantico department, A. foreroi sp. nov. (male) from Vaupes department, A. hilli sp. nov. (male) from Putumayo department and A. enigmaticus sp. nov. (male and female) from Santander department.

RESUMO

The spider genus Parachemmis Chickering, 1937 (Araneae: Corinnidae: Corinninae) is reported from Colombia for the first time. Parachemmis julioblancoisp. n. Martinez-G & Villarreal is described and illustrated from the Sierra Nevada de Santa Marta, Magdalena department. The exclusive morphology of the short and apically truncated retrolateral tibial apophysis and club-like tegular laminar process of the male palp indicates that the specimens described herein belong to a new species of Parachemmis. A map of the distribution of species in the genus is included.

RESUMO

The community structure of dung beetles in the middle and lower river basin of the Gaira river, Sierra Nevada de Santa Marta, Colombia, is described. Four sites were selected along an altitudinal gradient of 50-940 m for sampling from June to October, 2004. Dung beetles were captured using modified pitfall traps and manual recollections. We captured 7,872 individuals belonging to 29 species, distributed in 15 genera and five tribes of Scarabaeinae. Canthon and Onthophagus were the most diverse genera, each represented by six species. The sampled sites shared the following species: Onthophagus acuminatus Harold, O. clypeatus Blanchard, O. marginicollis Harold. Bocatoma was the most diverse site with 23 species; whereas Port Mosquito presented the highest abundance, with 3,262 individuals. Seven species represented 89 percent of all captures: Canthidium sp., Dichotomius sp., Uroxys sp. 1, Uroxys sp. 2, O. marginicollis, O. clypeatus and O. acuminatus. Of the 29 captured species, 17 belonged to the functional group of diggers and 10 were ball-rollers. We did not observe significant among-site differences in community structure. Abiotic factors such as altitude, temperature and humidity cannot explain observed variation in community structure across sites, indicating other variables such as vegetation cover, density of the vegetation and soil type may play a role in the community structure of these insects.

Se describe la estructura de la comunidad de escarabajos coprófagos en la cuenca media y baja del río Gaira, Sierra Nevada de Santa Marta, Colombia. Se seleccionaron cuatro sitios de muestreo a lo largo de un gradiente altitudinal de 50-940 m, realizándose muestreos desde junio hasta octubre, 2004. La captura de los escarabajos se realizó con trampas pitfall modificadas y colecta manual. Se capturaron 7,872 individuos pertenecientes a 29 especies, repartidos en 15 géneros y 5 tribus de Scarabaeinae. Canthon y Onthophagus fueron los géneros más diversos con seis especies cada uno. Las cuatro estaciones comparten tres especies: Onthophagus acuminatus Harold, O. clypeatus Blanchard, O. marginicollis Harold. Bocatoma tuvo el mayor número de especies, 23; mientras que Puerto Mosquito con 3.262 individuos presentó la mayor abundancia. Las especies Canthidium sp., Dichotomius sp, Uroxys sp.1, Uroxys sp.2, O. marginicollis, O. clypeatus y O. acuminatus representaron el 89 por ciento de la abundancia en el área de estudio. Entre las 29 especies capturadas; 17 pertenecen a los cavadores, 10 a los rodadores y dos residentes. No se registraron diferencias significativas entre las cuatro estaciones con respecto estructura de la comunidad. Tampoco se observó correlación entre los factores abióticos y la estructura de la comunidad. La altitud, temperatura y humedad no explican las diferencias en la distribución de la comunidad, indicando que otras variables, como la cobertura vegetal, la densidad de la vegetación y el tipo de suelo pueden jugar un papel en la estructura de la comunidad de estos insectos.

Assuntos

RESUMO

The community structure of dung beetles in the middle and lower river basin of the Gaira river, Sierra Nevada de Santa Marta, Colombia, is described. Four sites were selected along an altitudinal gradient of 50-940 m for sampling from June to October, 2004. Dung beetles were captured using modified pitfall traps and manual recollections. We captured 7,872 individuals belonging to 29 species, distributed in 15 genera and five tribes of Scarabaeinae. Canthon and Onthophagus were the most diverse genera, each represented by six species. The sampled sites shared the following species: Onthophagus acuminatus Harold, O. clypeatus Blanchard, O. marginicollis Harold. Bocatoma was the most diverse site with 23 species; whereas Port Mosquito presented the highest abundance, with 3,262 individuals. Seven species represented 89% of all captures: Canthidium sp., Dichotomius sp., Uroxys sp. 1, Uroxys sp. 2, O. marginicollis, O. clypeatus and O. acuminatus. Of the 29 captured species, 17 belonged to the functional group of diggers and 10 were ball-rollers. We did not observe significant among-site differences in community structure. Abiotic factors such as altitude, temperature and humidity cannot explain observed variation in community structure across sites, indicating other variables such as vegetation cover, density of the vegetation and soil type may play a role in the community structure of these insects.

Assuntos