The family Agaonidae is a group of pollinating fig wasps. They spend their larval stage inside the fruits of figs. The pollinating wasps (Agaoninae, Kradibiinae, and Tetrapusiinae) are the mutualistic partners of the fig trees. Extinct forms from the Eocene and Miocene are nearly identical to modern forms, suggesting that the niche has been stable over geologic time.[1]
Females emerge from ripe figs and fly to another fig tree with developing syconia (which contain the flowers). They enter the syconium via the ostiole, pollinate the flowers, and lay their eggs in some of the ovules. The ovules containing eggs develop into galls that support the growth of the wasp larvae. Prior to the final ripening of the fig, wingless males emerge from the galls they developed in. The males enter the galls of their winged sibling females and mate with them.[2]
The family has changed several times since its taxonomic appearance after the work of Francis Walker in 1846[3] described from the wasp genus Agaon.
Previously the subfamilies Epichrysomallinae, Otitesellinae, Sycoecinae, Sycoryctinae, Sycophaginae, and Agaoninae were the subdivisions of the family.[4] Recent works building strong molecular phylogenies with an extended sampling size have changed the composition of Agaonidae. The paraphyletic groups have been excluded; Epichrysomallinae was raised to family status (Epichrysomallidae), whereas Otitesellinae, Sycoecinae, Sycophaginae, and Sycoryctinae were transferred to Pteromalidae. New subfamilies have been instated (Kradibiinae and Tetrapusiinae).[5][6][7][8]
The pollinating female fig wasps are winged and in general dark, while the males are mostly wingless and whitish. This difference of color is probably due to a clear split in the gender role. Once they have mated, male and female fig wasps have different fates. In some fig species, such as Ficus subpisocarpa or Ficus tinctoria, the males have to chew a hole for the females to leave their natal fig. The winged female wasps can fly over long distances before finding another fig to oviposit in it, while the male dies after chewing a hole.
As the fig is closed by a tight ostiole, the female wasps have developed adaptations to enter. First, the mandibles of the female wasps have developed specialized mandibular appendages to help them crawl into the figs. These appendages are adapted to the host fig species, with for instance spiraled ostioles matched by spiral mandibular appendages.[10]
^Walker F (1846). List of the specimens of Hymenopterous insects in the collection of the British Museum. Part 1 Chalcidites. pp. vii+100pp.
^Bouček Z (1988). Australasian Chalcidoidea (Hymenoptera). A biosystematic revision of genera of fourteen families with a reclassification of species. pp. 832pp.
^Astrid Cruaud, Jean-Yves Rasplus, Junxia Zhang, Roger Burks, Gérard Delvare, Lucian Fusu, Alex Gumovsky, John T. Huber, Petr Janšta, Mircea-Dan Mitroiu, John S. Noyes, Simon van Noort, Austin Baker, Julie Böhmová, Hannes Baur, Bonnie B. Blaimer, Seán G. Brady, Kristýna Bubeníková, Marguerite Chartois, Robert S. Copeland, Natalie Dale-Skey Papilloud, Ana Dal Molin, Chrysalyn Dominguez, Marco Gebiola, Emilio Guerrieri, Robert L. Kresslein, Lars Krogmann, Emily Lemmon, Elizabeth A. Murray, Sabine Nidelet, José Luis Nieves-Aldrey, Ryan K. Perry, Ralph S. Peters, Andrew Polaszek, Laure Sauné, Javier Torréns, Serguei Triapitsyn, Ekaterina V. Tselikh, Matthew Yoder, Alan R. Lemmon, James B. Woolley, John M. Heraty. (2024). The Chalcidoidea bush of life: evolutionary history of a massive radiation of minute wasps. Cladistics, 40(1), 34-63.
^van Noort S, Compton SG (July 1996). "Convergent evolution of agaonine and sycoecine (Agaonidae, Chalcidoidea) head shape in response to the constraints of host fig morphology". Journal of Biogeography. 23 (4): 415–24. doi:10.1111/j.1365-2699.1996.tb00003.x.