Abstract:
Pollination of fig trees depends on mutualist wasps that reproduce within their flowers. Until recently, it was assumed that there was a short window of time during which a fig crop could be pollinated. Hence, pollination of figs was thought to depend on extreme efficiency of the wasps in locating receptive trees. In that context, extensive data on the Costa Rican fig tree Ficus pertusa L. have been very difficult to understand. In F. pertusa, figs of different crops attract wasps at different stages of their development. The crops that attract wasps the earliest in their development are the most heavily visited ones, but mature the fewest pollinator offspring and seeds on a per-fig basis. Using simulation models of pollinator population dynamics and field data, we show that (i) attractiveness of a crop is prolonged, (ii) wasps prefer large figs when given a choice, and (iii) the observed pattern of preferential early visitation of crops can be explained by temporal variations in pollinator abundance. This emphasizes the importance of population-level mechanisms to explain the fig/fig wasp mutualism.
Abstract:
Predators inflict high mortality on the 4 species of wasps associated with the fig Ficus pertusa in Monteverde, Costa Rica. One of these wasps is the obligated pollinator of the fig. The natural histories of several predators are described: an ant that feeds on wasps arriving to oviposit, moth and weevil larvae that destroy wasps as they develop within the fruits, a staphylinid beetle that feeds on mature wasps before they leave the fruits, and a group of birds that gleans wasps as they leave. The synchrony of arrival and departure of pollinators from the fig trees probably make them the species least vulnerable to predation. -from Author
PMID: 21236825;Abstract:
Interspecific interactions are traditionally displayed in a grid in which each interaction is placed according to its outcome (positive, negative or neutral) for each partner. However, recent field studies consistently find the costs and benefits that determine net effects to vary greatly in both space and time, inevitably causing outcomes within most interactions to vary as well. Interactions show 'conditionally' when costs and benefits, and thus outcomes, are affected in predictable ways by current ecological conditions. The full range of natural outcomes of a given association may reveal far more about its ecological and evolutionary dynamics than does the average outcome at a given place and time.
