Symbiotic associations of tephritid fruit flies
It is commonly thought of multicellular organisms as of biological units, or as
populations composed of individuals. However, all bear associated bacterial
communities that perform functions essential for their well-being – or in other
terms functions that may impact upon their fitness. Insects are practical models
to study such interactions as they are small, numerous and may sustain less
complex bacterial communities than larger organisms. Certain insects, like tephritid fruit flies are important agricultural pests; others, like blood sucking flies are important animal parasites. Understanding their relationships with their bacterial communities may offer novel opportunities for controlling them and in turn, the damage they cause.
Our research on symbiont-fly interactions is based on a symbiotic association - with the Yuval lab of Entomology (http://departments.agri.huji.ac.il/entomology/boaz_yuval/index.html).
Community adaptation in Ceratitis capitata, the Mediterranean fruit fly
The Mediterranean fruit fly (the medfly) is a widely distributed, polyphagous fly. Its larva grows within many kinds of fruits, causing great losses. While the medfly’s gut bacterial community is large and diverse, it expresses conserved functions (e.g. atmospheric nitrogen fixation and the ability to cause fruit rot). Knowledge of community composition and functions plays an increasing role in the control strategy known as the Sterile Insect Technique (SIT). Yet, we do not know if the bacterial community locally adapts to the fruit, affecting larval development. We investigate the effect of the fruit habitat on the fly's gut bacterial community and that of community members on the fly's behaviour and performance.
The unique association of Bactrocera olea, the olive fly with a gut symbiont
Bactrocera olea, the olive fly is a major pest of olives. It is one of a few insects able to overcome the chemical defences of green olives, with its larvae consuming the fruit and inflicting great damage to growers. The fly has a dominant symbiont, Candidatus Erwinia dacicola, a so-far uncultivated species. It is an important contributor to the fly's nitrogen metabolism and it is indispensable for growth in the green, but not in the black olive. This system, in conjunction with the analysis of other local monophagous flies, and the possibility to manipulate colonization of the fly's gut let us ask fundamental questions about the evolution of monophagous pest flies, and about trade-offs between life stages. Furthermore, this knowledge can be applied to cultivate the olive fly's symbiont, and enable adaptation of the fly to mass-rearing for the SIT.
Microbe-host dynamics in Philornis downsi, a parasite of Darwin finches
Philornis downsi is an invasive blood-feeding avian parasite that has invaded the Galapagos archipelago, inflicting high mortality to the small birds inhabiting the islands, prominently to Darwin finches. As part of a large international team aiming at controlling the parasite, we study which microbes are associated with the various life stages of the flies, the effect of bird host species, geography, and growth under lab conditions on the fly's gut community composition. We aim at finding a way to produce and keep fly colonies in the lab to help establish SIT; in addition using trapping experiments, we study whether gut community members affect the fly's behaviour.
Yuval, B., Lahuatte, P., Polpass, A.J., Causton, C.E., Jurkevitch, E., Kouloussis, N., and Ben-Yosef, M. 2019. Behavioral responses of the invasive fly Philornis downsi to stimuli from bacteria and yeast in the laboratory and the field in the Galapagos Islands. Insects. 10(12), 431;
Jose, P.A., Ben-Yosef, M., Jurkevitch, E., and Yuval, B. 2019. Symbiotic bacteria affect oviposition behavior in the olive fruit fly Bactrocera oleae. Journal of Insect Physiology. 117: p. 103917.
Zaada, D.S.Y., Ben-Yosef, M., Yuval, B. and Jurkevitch, E., 2018. The host fruit amplifies mutualistic interactions between Ceratitis capitata larvae and associated bacteria. bioRxiv, p.327668.
Ben-Yosef, M., Zaada, D.S.Y., Dudaniec, R.Y., Pasternak, Z., Jurkevitch, E., Smith, R.J., Causton, C.E., Lincango, M.P., Tobe, S.S., Mitchell, J.G., Kleindorfer, S., and Yuval, B. 2017. Host-specific associations among the microbiome of the parasitic fly Philornis downsi and Darwin’s finches. Molecular Ecology. 10.1111/mec.14219.
Pavlidi, N., Gioti, A., Wybouw, N., Dermauw, W., Ben-Yosef, M., Yuval, B., Jurkevitch, E., Kampouraki, A., Van Leeuwen, T., and Vontas, J. 2017. Transcriptomic responses of the olive fruit fly Bactrocera oleae and its symbiont Candidatus Erwinia dacicola to olive feeding. Scientific Reports 7, 42633, doi:10.1038/srep42633.
Blow F, Gioti A, Starns D, Ben-Yosef M, Pasternak Z, Jurkevitch E, Vontas J, Darby AC. 2016. Draft Genome Sequence of the Bactrocera oleae symbiont “Candidatus Erwinia dacicola”. Genome Announcements. 2016;4(5). doi: 10.1128/genomeA.00896-16.
Ben-Yosef, M., Pasternak, Z., Jurkevitch, E., Yuval, B. 2015. Symbiotic bacteria enable olive fly larvae to overcome host defences. Royal Society Open Science 2:7.