Zachary Griebenow

(he/him)

Looking over Nearctic Coleoptera at the Triplehorn Insect Collection

I am a fifth-year PhD student in the Ward laboratory. While the Formicidae are fascinating in many respects, their systematics has always been my area of interest within myrmecology. This is because I have always intuitively subscribed to the idea that the beginning of wisdom (in this case, understanding ants) is calling things by their proper name.

To that end, I am undertaking a systematic revision of the obscure subfamily Leptanillinae, with phylogeny inferred jointly from male morphology and phylogenomic data. This male-focused approach is unorthodox in systematic myrmecology, but has pragmatic justification in that males of the Leptanillinae are far easier to collect than the exclusively subterranean worker caste.

Surface segmentation of an undescribed male leptanilline (Leptanilla zhg-my06), produced by Georg Fischer

My examination of male leptanilline morphology particularly emphasizes their genitalia, which display critical phylogenetic signal. Moreover, despite the low diversity of the Leptanillinae, the male genitalia in this clade exhibit a peculiar variety of bizarre modifications, many of these not only unique among ants but unparalleled in the Hymenoptera as a whole. To better understand the great variety of structural modifications to male leptanilline genitalia, I have obtained micro-computed tomography scans of these structures in collaboration with the Evan Economo laboratory at the Okinawa Institute of Science & Technology and Adrian Richter at Friedrich Schiller University Jena. Further scans are being obtained at the Center for Molecular and Genomic Imaging at the University of California, Davis, and with Beamline 8.3.2 at the Advanced Light Source of the Lawrence Berkeley National Laboratory, University of California, Berkeley. These data will inform a comparative description of the male genitalia across the major subclades of the Leptanillinae.

An undescribed male morphospecies (Yavnella zhg-bt01), notable for minute size and lack of ocelli

In conjunction with examination of leptanilline males, I have obtained genome-scale data from across this clade using ultra-conserved elements (UCEs), acquired with Michael Branstetter’s et al. hymv2 probe set, and inferred the phylogeny of the Leptanillinae from these data using model-based techniques (ML and Bayesian inference). With male morphology thus contextualized in a phylogenetic framework, I am revising leptanilline taxonomy based primarily upon male morphology, supplemented by knowledge of workers.

Email: zgriebenow@ucdavis.edu

Curriculum vitae (PDF): Zachary Griebenow – academic C.V., June 2022

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Last updated: June 2022