Out of Australia and back again: the world-wide historical biogeography of non-pollinating fig wasps (Hymenoptera: Sycophaginae)

Abstract

Aim Figs (Ficus, Moraceae) are exploited by rich communities of often host-specific phytophagous wasps. Among them, gall-inducing Sycophaginae (Hymenoptera, Chalcidoidea) may share a common history with Ficus and their mutualistic pollinators (Agaonidae). We investigate here, for the first time, the phylogeny and biogeographical history of Sycophaginae and compare the timing of radiation and dispersion of major clades with available data on Ficus and fig pollinators. Reconstructing the history of their host colonization and association over space and time is central to understanding how fig wasp communities were assembled.Location World-wide.Methods Maximum likelihood and Bayesian analyses were conducted on 4267 bp of mitochondrial and nuclear DNA to produce a phylogeny of all genera of Sycophaginae. Two relaxed clock methods with or without rate autocorrelation were used for date estimation. Analyses of ancestral area were also conducted to investigate the geographical origin of the Sycophaginae.

A living fossil fig wasp (Hymenoptera, Agaoninae) developing in extant Neotropical fig species (Moraceae: Ficus, section Pharmacosycea)

“…Berg (2009) (Corner, 1967), North Atlantic land bridges (Cruaud et al, 2012) or long distance trans-oceanic dispersal, proposed for the association Tetrapus-Pharmacosycea in the New World (cf. Corner, 1967;Rønsted et al, 2005;Lopez-Vaamonde et al, 2009;Azuma et al, 2010;Cruaud et al, 2011). Furthermore, it questions the radiation of Ficus during the Tertiary after the break-up of Gondwana proposed by Zerega et al (2005) and Cruaud et al (2011).…”

“…Corner, 1967;Rønsted et al, 2005;Lopez-Vaamonde et al, 2009;Azuma et al, 2010;Cruaud et al, 2011). Furthermore, it questions the radiation of Ficus during the Tertiary after the break-up of Gondwana proposed by Zerega et al (2005) and Cruaud et al (2011). Since the Agaoninae females are short-lived and do not feed as adults, long distance dispersal, or emigration, is intimately subject to ecological factors, e.g., the fig wasps must accompany the fig host in their migration (Corner, 1958;Ramírez et al, 2011).…”

“…Consequently, the author suggest that dispersion of Ficus seeds and its suits of sycophilous wasps and other associated organisms by wind, flying, or aquatic vertebrates displacing over long transoceanic distances, do not seem to have played a historical role in the intercontinental dispersion of the main groups of sycophillous wasps and other invertebrates (cf. Cruaud et al, 2011) for Sycophaginae dispersal. Due to the presence of two mandibular appendages and a membranous un-carinated gular bridge, as pleisiomorphies Agaoninae characters, the author suggests that Hexapus is the most ancestral clade of all extant fig pollinator genera; as well as, the sister clade of extant Tetrapus.…”

“…According to Berg and Corner (2005), events of long-distance in Ficus dispersal will probably rarely result in reproduction and establishment by absence of pollinators, and population of trees to allow establishment of the pollinators as well. However, Cruaud et al (2011) proposed fruit pigeons, in part, for long distance trans-oceanic dispersal for fig fruits. Ecologically, Ficus provides one of the most important continuous food resources year around, e.g., Harrison (2005) noted that over 1 200 vertebrate species feed on figs.…”

First record of a non-pollinating fig wasp (Hymenoptera: Sycophaginae) from Dominican amber, with estimation of the size of its host figs

“…Molecular clock analyses suggest that Sycophaginae may have originated in the Palaeocene (50-40 Ma), after the break-up of Gondwana (Cruaud et al 2011a), but they have subsequently achieved a pantropical distribution. There are only about 60 species of Sycophaginae described to date, but the real diversity of the group is hard to estimate due to the high number of undescribed species found in recent studies (Cruaud et al 2011b, Farache et al 2013, Farache and Rasplus 2014.…”