Foundress re-emergence and fig permeability in fig tree–wasp mutualisms

Abstract

Some female pollinating fig wasps (foundresses) re‐emerge from figs after oviposition/pollination. We investigated why this occurs in the mutualism between the gynodioecious Ficus montana and Liporrhopalum tentacularis. Re‐emergence increased with foundress density in figs and some foundresses oviposited in two male figs, indicating that they re‐emerge because of oviposition site limitation. Re‐emergence was independent of fig diameter, indicating that permeability is not because of fig age at entry. Rather, as some foundresses also pollinate two female figs we suggest permeability is selected for because it increases pollinator production and/or efficiency (although, potentially opposing these hypotheses, we also found between‐tree differences in permeability in male figs). In addition, we show that re‐emergence is much more common than previously suspected, and more common from gynodioecious than monoecious fig species. We argue that our findings in F. montana could explain this pattern of incidence.

Fauna de Hymenoptera em Ficus spp. (Moraceae) na Amazônia Central, Brasil

“…As fundadoras penetram no sicônio através do ostíolo, polinizam as flores femininas e depositam ovos nos ovários de algumas delas. Na seqüência, com algumas exceções (WARE & COMPTON, 1992;GIBERNAU et al, 1996;CHEN et al, 2001;MOORE et al, 2003), as fêmeas morrem no interior do sicônio e seus corpos permanecem no lúmen. Durante as semanas seguintes, frutos (aquênios) se desenvolvem nas flores polinizadas e larvas de vespas polinizadoras crescem em flores nas quais ovos foram depositados, formando uma galha.…”

Evolution of the scale and manner of brother competition in pollinating fig wasps

“…Of the wasps studied here, Moore et al (2003) concluded from data published by Ware & Compton (1992) that the females of one species, Allotriozoon heterandromorphum, disperse from their figs. In another study where the focus was on sex ratio (Kjellberg et al 2005), we found no evidence for females leaving figs and we believe that the foundresses were overlooked in the Ware & Compton (1992) study cited by Moore et al (2003). When not all females contribute to the brood, or do so in unequal proportions, the optimal sex ratio is more female biased than with equal contributions (Frank 1985;Moore et al 2005).…”

“…In light of their highly femalebiased sex ratios (Herre et al 1997), it is thus surprising that brother-brother fighting and male dispersal may have evolved as many as six times in pollinating fig wasps (Michaloud, 1988;Greeff et al 2003). In this study, our aim was to determine why the kin competition-kin structure problem has been resolved differently Moore et al 2003 for examples where females have evolved a mechanism to spread their eggs over several figs). Each egg is laid in an individual flower, each forming a distinct gall inside the inflorescence.…”

“…In pollinating fig wasps, such as those studied here, relatedness of competing males can be determined in an alternative way by counting the foundresses that oviposit in the fig. Several studies have argued that counting foundresses can also be flawed, because in some species foundresses may leave the fig after oviposition (Moore et al 2003;Zavodna et al 2007) and in other species not all females found inside the fig contribute to the progeny (Molbo et al 2004). Of the wasps studied here, Moore et al (2003) concluded from data published by Ware & Compton (1992) that the females of one species, Allotriozoon heterandromorphum, disperse from their figs.…”

“…Several studies have argued that counting foundresses can also be flawed, because in some species foundresses may leave the fig after oviposition (Moore et al 2003;Zavodna et al 2007) and in other species not all females found inside the fig contribute to the progeny (Molbo et al 2004). Of the wasps studied here, Moore et al (2003) concluded from data published by Ware & Compton (1992) that the females of one species, Allotriozoon heterandromorphum, disperse from their figs. In another study where the focus was on sex ratio (Kjellberg et al 2005), we found no evidence for females leaving figs and we believe that the foundresses were overlooked in the Ware & Compton (1992) study cited by Moore et al (2003).…”