Divvying up an incubator: How parasitic and mutualistic fig wasps use space within their nursery microcosm

Ghara, Mahua; Ranganathan, Yuvaraj; Krishnan, Anusha; Gowda, Vishwas; Borges, Renée M.

doi:10.1007/s11829-014-9300-9

Cited by 26 publications

(37 citation statements)

References 48 publications

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“…Therefore, they need to pierce and explore the substrate (3,6), locate the host, and sometimes also pierce through the host's integument (44)(45)(46)(47), which is all done with the ovipositor apparatus only. Although the probing behavior of parasitic wasps has been repeatedly mentioned in the literature (3,6,17,18,(48)(49)(50)(51), no quantitative studies have been performed until now. Here, we show evidence that wasps are able to explore a large space from a single puncture point and that they use relative valve motions to insert and steer the ovipositor.…”

Section: Discussionmentioning

confidence: 99%

Mechanisms of ovipositor insertion and steering of a parasitic wasp

Cerkvenik

Straat

Gussekloo

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

111

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Drilling into solid substrates with slender beam-like structures is a mechanical challenge, but is regularly done by female parasitic wasps. The wasp inserts her ovipositor into solid substrates to deposit eggs in hosts, and even seems capable of steering the ovipositor while drilling. The ovipositor generally consists of three longitudinally connected valves that can slide along each other. Alternative valve movements have been hypothesized to be involved in ovipositor damage avoidance and steering during drilling. However, none of the hypotheses have been tested in vivo. We used 3D and 2D motion analysis to quantify the probing behavior of the fruit-fly parasitoid Diachasmimorpha longicaudata (Braconidae) at the levels of the ovipositor and its individual valves. We show that the wasps can steer and curve their ovipositors in any direction relative to their body axis. In a soft substrate, the ovipositors can be inserted without reciprocal motion of the valves. In a stiff substrate, such motions were always observed. This is in agreement with the damage avoidance hypothesis of insertion, as they presumably limit the overall net pushing force. Steering can be achieved by varying the asymmetry of the distal part of the ovipositor by protracting one valve set with respect to the other. Tip asymmetry is enhanced by curving of ventral elements in the absence of an opposing force, possibly due to pretension. Our findings deepen the knowledge of the functioning and evolution of the ovipositor in hymenopterans and may help to improve man-made steerable probes.Diachasmimorpha longicaudata | ovipositor kinematics | buckling avoidance | spatial probing | minimally invasive probe F rom a mechanical perspective, it is very difficult to drill into a solid substrate with a very thin probe, because it can easily bend and break. Parasitic wasps, however, do this regularly when they use their slender ovipositors to search for hosts in solid substrates, such as fruits or even wood (1-3).The general morphology of the ovipositor is similar across all wasp species (4, 5); it consists of four elements, called valves, of which two are often merged such that three functional valves remain (Fig. 1). In most species, the distal part of the ovipositor is morphologically distinct (3, 6), which we will refer to as the tip. The valves can slide along each other (5, 7) and do not get dislocated under natural conditions, because they are longitudinally connected via a tongue-and-groove mechanism (5, 8-10). The ovipositor and the "wasp waist," a constriction of the body between the first and second abdominal segment (11), are essential in probing behavior and are therefore considered to be instrumental in the evolution of the order (11-15). The shape, structure, and mechanical properties of the ovipositors are putatively adapted to the substrates into which the animals need to probe (6,(16)(17)(18), and because both substrates and hosts are so diverse, this might have resulted in high species diversification of the hymenopterans (13,14). Howeve...

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Section: Discussionmentioning

confidence: 99%

Mechanisms of ovipositor insertion and steering of a parasitic wasp

Cerkvenik

Straat

Gussekloo

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

111

View full text Add to dashboard Cite

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“…Because ephemeral patch communities are defined by spatiotemporally fluctuating resource availability, the strength of competition is also expected to vary geographically and over time (Thompson and Cunningham 2002;Thompson 2005). While the strength of competition among nonpollinating fig wasps has not been estimated, interspecific competition among nonpollinators should be comparable to that of pollinators where ovule resources are limiting and overlapping (e.g., Ghara et al 2014). Observations from wild populations find that nonpollinators regularly compete with pollinators for access to overlapping ovule resources (e.g., West and Herre 1994;Kerdelhué and Rasplus 1996;West et al 1996;Kerdelhué et al 2000;Ghara and Borges 2010), and experimental manipulations suggest that observational studies likely underestimate competition (Raja et al 2014).…”

Section: Naturalmentioning

confidence: 99%

Trade-Offs and Coexistence in Fluctuating Environments: Evidence for a Key Dispersal-Fecundity Trade-Off in Five Nonpollinating Fig Wasps

Duthie

Abbott

Nason

2015

The American Naturalist

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. abstract: The ecological principle of competitive exclusion states that species competing for identical resources cannot coexist, but this principle is paradoxical because ecologically similar competitors are regularly observed. Coexistence is possible under some conditions if a fluctuating environment changes the competitive dominance of species. This change in competitive dominance implies the existence of trade-offs underlying species' competitive abilities in different environments. Theory shows that fluctuating distance between resource patches can facilitate coexistence in ephemeral patch competitors, given a functional trade-off between species dispersal ability and fecundity. We find evidence supporting this trade-off in a guild of five ecologically similar nonpollinating fig wasps and subsequently predict local among-patch species densities. We also introduce a novel colonization index to estimate relative dispersal ability among ephemeral patch competitors. We suggest that a dispersal ability-fecundity trade-off and spatiotemporally fluctuating resource availability commonly co-occur to drive population dynamics and facilitate coexistence in ephemeral patch communities.

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“…These non-pollinating fig wasps (NPFWs) include the gallers Apocryptophagus stratheni, Apocrytophagus testacea and Apocryptophagus fusca, as well as the parasitoids Apocryptophagus agraensis, Apocrypta sp 2 and Apocrypta westwoodi. Based on published experiments and ongoing investigations (Ghara et al, 2014;Ghara, Yadav, Krishnan and Borges, unpublished data), we have established the following putative gallereparasitoid (i.e. preyepredator) associations: 1) C. fuscicepseA.…”

Section: Introductionmentioning

confidence: 85%

“…These wasps could be gallers, kleptoparasites feeding on galled plant tissue, parasitoids or hyperparasitoids and develop within the syconium (Cook and Rasplus, 2003;Herre et al, 2008;Borges, 2015). All wasp species are usually highly specific to their natal fig species (Herre et al, 2008;Jousselin et al, 2008); however, a single parasitoid wasp species may parasitise several wasp species developing within the same syconium or in the same fig species Ghara et al, 2014;Borges, 2015). Therefore, in this tritrophic interaction, the predatory parasitoids could be generalists at the prey level but are specialists at the host plant level (sensu Vet and Dicke, 1992).…”

Section: Introductionmentioning

confidence: 99%

“…We selected a reasonably speciose community Ghara et al, 2011Ghara et al, , 2014, had established that predatory ants but not trophobiont-tending ants in this system learn to associate insect prey with plant volatiles (Ranganathan and Borges, 2009), and we also knew the predation levels of the ants on the different species of fig wasps . We therefore asked the following questions: 1) What are the CHC profiles of galler and parasitoid fig wasps developing within F. racemosa syconia, and how do they differ?…”

Section: Introductionmentioning

confidence: 99%

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