Nectar oasis produced by Agave marmorata Roezl. (Agavaceae) lead to spatial and temporal segregation among nectarivores in the Tehuacán Valley, México

JUAN FRANCISCO ORNELAS; MARIANO ORDANO; ANGÉLICA HERNÁNDEZ; JUAN CARLOS LÓPEZ; LUIS MENDOZA; YARENI PERRONI

JOURNAL OF ARID ENVIRONMENTS

Elsevier Science Ltd.

Lugar: Amsterdam, Netherlands; Año: 2002 vol. 52 p. 37 - 51

0140-1963

We investigated temporal and spatial segregation of nectarivores at Agave marmorata inflorescences in Tehuacán, México. Using survival analysis, a technique in which data are treated as censored, we found temporal segregation among insects, hummingbirds, and perching birds during the most nectar-limited time. Survivorship curves of hummingbirds and orioles were not significantly different from each other, however, temporal segregation was observed within hummingbirds according to body size and territorial behavior. Temporal segregation among hummingbirds is interpreted as a way to reduce risk of injury. This way hummingbirds meet theirshort-term energy demands and co-existence may be facilitated in a nectar oasis. In contrast, survivorship curves of oriole species were not statistically different with each other, but spatial segregation is suspected; Scott’s Orioles segregate by visiting agaves with taller inflorescences sooner than visiting those with shorter inflorescences. These results along with those of foragingbehavior and floral shifts suggest that orioles are the legitimate pollinators of this century plant.