No abstract

A partir de la evaluación de la morfología floral, la fenología reproductiva, la biología floral, los visitantes florales y determinación de polinizadores se describe la estrategia de polinización de una población de la palma Syagrus smithii de la Amazonia colombiana. Syagrus smithii es una palma solitaria de hasta 10 m de alto; produjo de una a tres inflorescencias bisexuales, con flores estaminadas y pistiladas agrupadas en tríadas, con una flor central femenina y dos laterales masculinas. Las inflorescencias abrieron de día y las flores estuvieron activas de noche. Una inflorescencia permaneció activa en promedio 28 días; la fase masculina se extendió durante los primeros 14 días, seguida de una fase inactiva de 10 días, y la fase final pistilada por cuatro días. En fase masculina, las inflorescencias fueron visitadas por 37 y en fase femenina por 21 especies de insectos, principalmente de los órdenes Coleoptera‚ Hymenoptera y Diptera. Los visitantes accedieron en busca de polen y lugar para reproducción. De todos los visitantes‚ pocas especies fueron polinizadores. Los valores de los índices (IVIP) e (IRP) indicaron que Mystrops sp. nov. 2 y Mystrops sp nov. 3 (Nitidulidae: Coleoptera) fueron los principales polinizadores, mientras que especies de coleópteros como Microstates sp.2 y Sibinia sp. 1 fueron polinizadores secundarios. Dado que los polinizadores desarrollaban sus ciclos de vida en las inflorescencias‚ sugerimos la existencia de un sistema de mutua dependencia entre polinizadores y la palma, el cual asegura la presencia de los polinizadores a lo largo del año y palmas con semillas viables.

The environmental unsustainability of African oil palm crops is a growing worldwide concern, and the macauba palm in tropical Southern America surges as the most viable substitute for the production of first‐generation biodiesel as a renewable fuel. Large‐scale cultivation of the macauba palm, however, is bound to suffer a major setback due to the fast emergence of a florivorous pest threat, Cyclocephala forsteri, a scarab beetle species that can severely reduce fruit yield. Like other congenerics, female and male C. forsteri are night‐foraging and driven in large numbers to macauba palm inflorescences by specific volatile organic compounds. In the present study, we assessed the kairomonal cues involved in this plant–florivore interaction and their potential application in selective pest management strategies. Headspace samples of the floral fragrance of macauba palms at our study site in Central Brazil were largely dominated by 4‐methylanisole (>97% relative amount), which along with the minor constituents 2‐isopropyl‐3‐methoxypyrazine and 2‐sec‐butyl‐3‐methoxypyrazine triggered electroantennographic responses from both female and male C. forsteri. Field behavioural assays evidenced that beetles of this species were exclusively attracted to scented traps baited with 4‐methylanisole. Increased total scent discharge attained with an ultrasonic piezoelectric diffuser has positively influenced attractiveness efficiency of the trapping setup. 4‐Methylanisole is hereby identified as yet another volatile kairomone involved in highly selective attraction of potential pest florivorous cyclocephaline scarabs associated with economically exploitable palms and should be viewed as a key element in short‐term integrated management plans for the cultivation of the macauba palm in South America.

No abstract

Solitary, dioecious, and mostly endemic to Andean cloud forests, wax palms (Ceroxylon Bonpl. ex DC. spp.) are currently under worrisome conservation status. The establishment of management plans for their dwindling populations rely on detailed biological data, including their reproductive ecology. As in the case of numerous other Neotropical palm taxa, small beetles are assumed to be selective pollinators of wax palms, but their identity and relevance in successful fruit yield were unknown. During three consecutive reproductive seasons we collected data on population phenology and reproductive and floral biology of three syntopic species of wax palms native to the Colombian Andes. We also determined the composition of the associated flower-visiting entomofauna, quantifying the extent of the role of individual species as effective pollinators through standardized value indexes that take into consideration abundance, constancy, and pollen transport efficiency. The studied populations of C. parvifrons (Engel) H. Wendl., C. ventricosum Burret, and C. vogelianum (Engel) H. Wendl. exhibit seasonal reproductive cycles with marked temporal patterns of flower and fruit production. The composition of the associated flower-visiting entomofauna, comprised by ca. 50 morphotypes, was constant across flowering seasons and differed only marginally among species. Nonetheless, a fraction of the insect species associated with pistillate inflorescences actually carried pollen, and calculated pollinator importance indexes demonstrated that one insect species alone, Mystrops rotundula Sharp, accounted for 94%–99% of the effective pollination services for all three species of wax palms. The sequential asynchronous flowering of C. parvifrons, C. ventricosum, and C. vogelianum provides an abundant and constant supply of pollen, pivotal for the maintenance of large populations of their shared pollinators, a cooperative strategy proven effective by high fruit yield rates (up to 79%). Reproductive success might be compromised for all species by the population decline of one of them, as it would tamper with the temporal orchestration of pollen offer.