A hitchhiker’s guide to a crowded syconium: how do fig nematodes find the right ride?

Abstract

Summary1. Organisms with low mobility, living within ephemeral environments, need to find vehicles that can disperse them reliably to new environments. The requirement for specificity in this passenger-vehicle relationship is enhanced within a tritrophic interaction when the environment of passenger and vehicle is provided by a third organism. Such relationships pose many interesting questions about specificity within a tritrophic framework. 2. Central to understanding how these tritrophic systems have evolved, is knowing how they function now. Determining the proximal cues and sensory modalities used by passengers to find vehicles and to discriminate between reliable and non-reliable vehicles is, therefore, essential to this investigation.

Absence of the Parasite Escovopsis in Fungus Garden Pellets Carried by Gynes of Atta sexdens

“…Both horizontal and vertical transmission can be used by some specific parasites to infect a host population (Fries & Camazine, 2001). However, as to parasites that possess specific mechanisms such as chemotaxis , vertical transmission is more plausible: in fig systems, the plant parasitic nematode Schistonchus presents chemotaxis to its vector (fig wasp, pollinator of figs) and thus accomplishes its vertical transmission by this mechanism (Krishnan et al, 2010). Thus, this example contrasts with the non-vertical transmission of Escovopsis because it also presents chemotaxis, in this case, to the mutualistic fungus of leaf-cutting ants (Gerardo et al, 2006a), and since this mutualist is vertically transmitted by winged gynes.…”

“…vertical transmission. This hypothesis (Vovlas et al, 1992;Krishnan et al, 2010). Thus, an additional investigation of the presence of Escovopsis in fungal pellet, the most likely location for this parasite to be present in case of vertical transmission (Currie et al, 1999), is critical.…”

Phoresy in the field: natural occurrence of Trichogramma egg parasitoids on butterflies and moths

“…of Pieris butterfly eggs in the Netherlands (Fatouros and Huigens, unpublished data;van Heiningen et al 1985), our data suggest that only a small portion of Trichogramma wasps use adult hosts as transport vehicles to oviposition sites. Besides host specificity, patchy or extreme habitats, like deserts, might select for the evolution of a phoretic relationship (Houck and Oconnor 1991;Krishnan et al 2010;Vinson 1985). Extensive field studies correlating egg parasitism by Trichogramma species to the prevalence of phoretic wasps are needed to confirm this hypothesis.…”

Galling problems – the Fergusobia nematode/Fergusonina fly mutualism on myrtaceous hosts

“…If the male and female fly larvae have different cuticular hydrocarbons, the ne-matodes could use these as cues for sex discrimination. The fig/wasp/nematode tritrophic interactions in Ficus sycones (Krishnan et al, 2010) are mediated via volatiles produced by the wasps.…”