Distribución espacial de Cordyceps spp. (Ascomycotina: Clavicipitaceae) y su impacto sobre las hormigas en selvas del piedemonte amazónico de Colombia
Loading...
Date
Authors
Sanjuán, Tatiana
Henao, Luis Guillermo
Amat García, German D.
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Costa Rica
Abstract
Description
Se estudió la diversidad del género Cordyceps, hongo entomopatógeno, en hormigas del piedemonte Amazónico colombiano (450-600 msnm, enero y mayo de 1998, épocas seca y lluviosa, respectivamente). La recolección de hormigas sanas y parasitadas por Cordyceps se llevó a cabo en tres bosques con distintos regímenes de perturbación: natural, antrópico y poco perturbado. Se establecieron 100 cuadrantes de 1 m2 por cada bosque. Las muestras fueron tomadas en hojarasca, arbustos y troncos como sustratos, y cada 50 cm hasta 2 m de altura los estratos verticales. El género Azteca fue el predominante en el bosque poco perturbado, mientras Camponotus, Pheidole y Crematogaster abundaron en los bosques con perturbación natural y antrópica. El bosque con perturbación natural presentó 759 individuos de C. unilateralis y 69 de C. lloydii var. binata parasitando hormigas Camponotus spp. (Formicidae: Formicinae). Se encontraron sólo seis casos de C. kniphofioides var. ponerinarum y C. australis en las hormigas Paraponera clavata y Pachycondyla crassinoda (Formicidae: Ponerinae). En el bosque perturbado antrópicamente se presentaron 34 ejemplares de C. unilateralis en Camponotus mientras que en el menos perturbado no se observaron hormigas parasitadas. Se halló que las hormigas Camponotus spp. que son parasitadas por C. unilateralis y C. lloydii var. binata se ubican preferencialmente en el sustrato hoja, hasta 1 m de altura. Se determinó que la incidencia de la interacción Cordyceps / hormiga no está influenciada por el estado de conservación del bosque; sin embargo, la variación de la humedad relativa y la presencia o ausencia de la hormiga hospedera son factores que influyen en la diversidad de Cordyceps en hormigas. Se encontró, además, que la distribución microespacial de la interacción sigue un patrón determinado, aportando más argumentos a la hipótesis de que los mecanismos de dispersión de Cordyceps coevolucionaron con la hormiga influenciando sus códigos feromonales.
Entomopathogenic fungi of the genus Cordyceps were sampled in the foothills of the Colombian Amazon region (450 – 600 msnm altitude, January and May, 1998, i.e. dry and wet seasons, respectively). Healthy and Cordyceps-parasitized ants from a nearly pristine, a naturally disturbed and a human-disturbed forests were collected on 100 quadrants (1 m2) per forest. Litter, shrubs and trunks were explored as substrates, and samples were gathered in vertical strata from 50 cm to 2 m high. Azteca was the predominant ant genus in near pristine forest whereas Camponotus, Pheidole and Crematogaster were dominant in disturbed forests. In the naturally disturbed forest we found 759 individuals of Cordyceps unilateralis and 69 of C. lloydii var. binata parasitizing Camponotus spp. (Formicidae: Formicinae), whereas C. kniphofioides var. ponerinarum and C. australis were found only in six cases infecting the ants Paraponera clavata and Pachycondila crassinoda (Formicidae: Ponerinae). In the human disturbed forest it were found 34 individuals of C. unilateralis on Camponotus. In the near pristine forest we did not find parasitized ants. The Camponotus spp. ants parasitized by C. unilateralis and C. lloydii var. binata were found predominantly in the substratum foliage up to 1 m. It was concluded that the incidence of Cordyceps–ant interactions is not influenced by the conservation status of the forest. Instead, relative humidity and presence/absence of host ants appear to be key factors. Also, the microspatial distribution of the interactions seems to follow a definite pattern. This work observations support the hypothesis on coevolution of dispersion mechanisms in Cordyceps and ant pheromonal codes.
Entomopathogenic fungi of the genus Cordyceps were sampled in the foothills of the Colombian Amazon region (450 – 600 msnm altitude, January and May, 1998, i.e. dry and wet seasons, respectively). Healthy and Cordyceps-parasitized ants from a nearly pristine, a naturally disturbed and a human-disturbed forests were collected on 100 quadrants (1 m2) per forest. Litter, shrubs and trunks were explored as substrates, and samples were gathered in vertical strata from 50 cm to 2 m high. Azteca was the predominant ant genus in near pristine forest whereas Camponotus, Pheidole and Crematogaster were dominant in disturbed forests. In the naturally disturbed forest we found 759 individuals of Cordyceps unilateralis and 69 of C. lloydii var. binata parasitizing Camponotus spp. (Formicidae: Formicinae), whereas C. kniphofioides var. ponerinarum and C. australis were found only in six cases infecting the ants Paraponera clavata and Pachycondila crassinoda (Formicidae: Ponerinae). In the human disturbed forest it were found 34 individuals of C. unilateralis on Camponotus. In the near pristine forest we did not find parasitized ants. The Camponotus spp. ants parasitized by C. unilateralis and C. lloydii var. binata were found predominantly in the substratum foliage up to 1 m. It was concluded that the incidence of Cordyceps–ant interactions is not influenced by the conservation status of the forest. Instead, relative humidity and presence/absence of host ants appear to be key factors. Also, the microspatial distribution of the interactions seems to follow a definite pattern. This work observations support the hypothesis on coevolution of dispersion mechanisms in Cordyceps and ant pheromonal codes.
Keywords
cordyceps, ants, entomopathogenic fungi, tropical rain forest, biological control, camponotus, fungal ecology