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Motoaki Kinoshita Eiiti Kasuya Tetsukazu Yahara 《Researches on Population Ecology》1998,40(2):239-242
The sex ratio of the pollinator fig wasp,Blastophaga nipponica Grandi (Agaonidae), was examined in an experiment manipulating the number of foundresses. The sex ratio ofB. nipponica was conditional on the number of foundresses and corresponded to the qualitative prediction of the local mate competition
(LMC) theory that the proportion of males increases as foundress number increases. However, the sex ratio ofB. nipponica was consistently more female-biased than predicted by extended LMC theories that incorporated effects of inbreeding, and
these deviations were statistically significant. Plausible factors that would make predictions more female-biased are discussed. 相似文献
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Tomoyuki Kameyama Rhett Harrison Norio Yamamura 《Researches on Population Ecology》1999,41(3):243-252
The relationship between fig trees and their pollinator wasps is a well-known example of species-specific obligate mutualism.
In this article we present a stochastic model of this mutualistic system, referring to data on a dioecious fig (Ficus schwarzii) in Borneo, and examine the conditions for the persistence of a wasp population for a given period. (1) When the average
duration of the flowering interval of fig trees is short, even a small fig population can sustain a wasp population successfully.
A population whose average period of flowering cycle is half that of another population can sustain a wasp population with
a number of trees less than half of the other population. (2) The wasp survival rate (WSR) is higher when (a) the variation
of the interval periods of fig flowering is smaller, (b) the fig population size is larger, and (c) figs can prolong their
receptivity to wait for a wasp if no wasps are available. (3) WSR is predictable from the average proportion of the fig's
receptive phases, in which wasps are available, to their total receptive phases. (4) The persistence period of a wasp population
increases exponentially with the number of fig trees. Based on these results we propose a new hypothesis, as a possible scenario,
on the evolution of dioecy from monoecy in Ficus.
Received: November 13, 1998 / Accepted: July 14, 1999 相似文献
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