Torres, Marina , Ashman, Tia-Lynn , Freitas, Leandro .
Revisiting the hermits: the relationship between self-compatibility and hummingbird foraging behavior.
Neotropical ornithophilous species are often pollinated by hummingbirds, which generally exhibit one of two basic strategies.The first involves territorial behavior, which is characterized by perching and feeding within a fairly well circumscribed area. Alternatively,hermit hummingbirds exhibit a feeding strategy known as traplining.This behavior consists of a wide search for food, i.e., a bird does not remain in one area for long, but spends much time flying among plants. A territorial bird will reduce pollen movement out of an area and also reduce pollen movement into an area by keeping other birds away. In contrast, the potential for inbreeding seems much lower in plants pollinated by hermits. Thus, high selective pressures are expected to maintain self-incompatibility in plants pollinated by non-hermits. Besides the foraging behavior, other plant traits can also be related to mating system as life habit, plant aggregation and floral display. This study seeks to answer the following questions: (1) What is the incidence of self-incompatibility in hummingbird-pollinated plants? (2) Is self-incompatibility more common in non-hermit pollinated species? (3) Are any plant traits, e.g., life habit, related to mating system for a neotropical plant assemblage? We conducted a literature review of studies that determined plant mating system for hummingbird pollinated species. Also, we utilized hand-pollination experiments to determine the mating system of a particular hummingbird-pollinated plant guild in Itatiaia National Park, Brazil. Self-incompatibility index (ISI) was estimated as the ratio of fruit set (or seed set) after self- and cross-pollination. Linear mixed model was used to compare ISI among plants pollinated by three hummingbird groups (hermits,mixed, non-hermits). Plant habit (woody vs. herbaceous) and family were included in the model as fixed and random effects, respectively.Self-incompatibility (ISI<0.3) was identified for 33% of the species. Hummingbird-habit interaction (p=0.01) affected ISI. Herbs pollinated by a mixed hummingbird assemblage had a lower ISI than those pollinated by non-hermits (p=0.002).Herbaceous plants pollinated by hermits had a marginally higher ISI than woody plants (p=0.09). In addition, plant family affected ISI (p=0.007). For the plant guild studied, there was relation between ISI and plant aggregation(p=0.006) and life habit (p=0.002), but no relation for hummingbird foraging behavior, plant density, and floral display. Though hummingbirds differ in their foraging strategies, these behavioral differences do not alter plant mating systems. Instead, phylogenetic relatedness seems to be the strongest determining factor for the mating systems of hummingbird pollinated plants.
Log in to add this item to your schedule
1 - University Of Pittsburgh, Department Of Biological Sciences, 4249 Fifth Avenue & Ruskin, Pittsburgh, PA, 15260, USA
2 - Botanical Garden of Rio de Janeiro, Rua Pacheco Lećo, 915, Horto, Rio de Janeiro, RJ, 22460-030, Brazil
Presentation Type: Poster:Posters for Topics
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM