REGULATION OF SEED AND POLLINATOR PRODUCTION IN THE FIG FIG WASP MUTUALISM

1. Female agaonine fig wasps enter Fic lts fruits (figs), where they p ollinate the Flowers and oviposit into the ovaries of a proportion of the flowers via their styles. The fig trees are totally dependent on t hese fig wasps for sexual reproduction, as the wasps fertilize the fig s' seeds and transfer pollen between trees, while the wasps need the f ig trees' ovaries as feeding sites (galled seeds) for their progeny. S ince the wasp progeny destroy seeds, the question arises as to why sel ection has not led to increasingly higher fig wasp fecundities and the eventual collapse of the mutualism. 2. The stability of the mutualism could be maintained by pollinators having short ovipositors, restrict ing oviposition to short-styled flowers so that long-styled flowers pr oduce seeds. However, in most of the monoecious Ficus species where me asurements were taken, pollinators generally possessed ovipositors of sufficient length to reach the ovaries of a large majority of the Rowe rs. This was confirmed bq! the presence of pollinator progeny in flowe rs with long styles. 3. Complete seed destruction may also be avoided by a proportion of fig ovaries being inviolate to oviposition by fig w asps. independent of their style lengths. However, experimental increa ses in pollinator foundresses per fig in F, burtt-davyi showed that al l the ovaries that could be reached by the wasps' ovipositors were pot entially exploitable by agaonine fig wasps. 4. Relative production of wasps and seeds was found to be largely dependent on the interplay bet ween the number of eggs inside each wasp, the number of accessible ova ries in individual figs, and the average number of foundresses enterin g each fig. On average, there were not enough foundresses entering eac h fig to utilize all accessible ovaries, 5. Possible factors affecting the total entry numbers of wasps into figs include ostiolar closure r ates and wasp population densities in the areas surrounding fig trees. As many ovaries remain unused because of a frequent shortage of wasp eggs per fig, fig trees can continue to produce enough seeds for the c ontinued evolutionary stability of the fig-fig wasp mutualism.