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Majeed Askari Seyhoei

cosupervised with Jacques van Alphen at Leiden University, The Netherlands

* Majeed defended his thesis on February 3rd, 2010*

In my PhD project, I studied the relationships between parasitoids, hosts and climate from an evolutionary point of view by using hymenopteran parasitoids as a model system. I used a comparative approach to study the variation in life-history traits of species and populations from different habitats. I showed that closely related species manipulate their host behaviour differently and allocate their essential resources to different life-history traits. Metabolic rate and energy reserves varied strongly among the species. Energy reserves were found to vary substantially between populations from different climate zones. A molecular study revealed genetic divergence between the populations. The pattern a divergence partially reflected variation in life-history among the populations. To conclude, I suggest that life-history traits of parasitoids are subject to natural selection pressures from both host and climate. Resource allocation and host manipulation in parasitoids is species specific and resource allocation is highly diverged among populations to fit habitat requirements.

Leptopilina clavipes

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image Herman Berkhoudt

We sequenced the complete genomes of a sexual and an asexual lineage of this parasitoid wasp. The latter are asexual because they are infected by a parthenogenesis-inducing Wolbachia bacterium. This infection became established roughly 100,000 years ago. The comparison of the two genomes provides insight into the genomic consequences of asexual reproduction. In particular, we are interested in the accumulation of mutations and the associated decay of genes in asexuals.

Ongoing work includes:

Publications

  • Geuverink E, Kraaijeveld K, van Leussen M, Chena F, Pijpe J, Linskens MHK, Beukeboom LW, van de Zande L 2018 Evidence for involvement of a transformer paralog in sex determination of the wasp Leptopilina clavipes. Insect Molecular Biology 27: 78-795
  • Kraaijeveld K, Anvar Y, Frank J, Schmitz A, Bast J, Wilbrandt J, Petersen M, Ziesmann T, Niehuis O, de Knijff P, den Dunnen JT, Ellers J 2016 Decay of sexual trait genes in an asexual parasitoid wasp. Genome Biology and Evolution 8:3685-3995.
  • Kraaijeveld K, Zwanenburg B, Hubert B, Vieira C, de Pater S, van Alphen JJM, den Dunnen JT & de Knijff P 2012 Transposon proliferation in an asexual wasp. Molecular Ecology 21: 3898-3906.
  • Kraaijeveld K, Franco P, de Knijff P, Stouthamer R & van Alphen JJM 2011 Clonal genetic variation in a Wolbachia-infected asexual wasp: horizontal transmission or historical sex? Molecular Ecology 20: 3644-3652.
  • Kraaijeveld K., Franco P., Reumer B.M. & van Alphen J.J.M. 2009 Effects of parthenogenesis and geographic isolation on female sexual traits in a parasitoid wasp. Evolution 63: 3085-3096.
  • Reumer B., Kraaijeveld K. & van Alphen J.J.M. 2007 Selection in the absence of males does not affect male-female conflict in the parasitoid wasp Leptopilina clavipes (Hymenoptera: Figitidae). Journal of Insect Physiology 53: 994-999.