Biology subjects

Stukel, M.

Publications and source records attributed to Stukel, M..

4 recordsLinked to original sources

bioRxiv2025

Phylogenomics and Fossilized Birth-Death Dating Reveals Gondawanan Origin and Extensive Post-Cretaceous Diversification of Worldwide Cicadidae.

The Cretaceous-Paleogene (K-Pg) mass extinction resulted in a massive turnover in biodiversity. The oldest fossils of the globally-distributed insect family Cicadidae date to the Paleocene, suggesting that this family diversified after the K-Pg boundary. We analyzed 490 nuclear Anchored Hybrid Enrichment loci as well as mitochondrial genomes for the Cicadidae, sampling all five subfamilies and 82% of tribes, using concatenated maximum-likelihood and multi-species coalescent approaches to resolve the phylogenetic relationships of Cicadidae subfamilies. We estimated divergence times of Cicadidae lineages using a fossilized birth-death model augmented into the multispecies coalescent with 44 fossil taxa. We estimated a Cretaceous origin for Cicadidae with four of the five subfamilies diversifying shortly after the K-Pg extinction event. Our fossilized birth-death tip-dating approach improved the precision of age estimates for many cicada clades compared to dates based on node-calibration from previous studies. Our results augment insight into how the K-Pg mass extinction shaped present-day diversity.

evolutionary biology↗

bioRxiv2025

Untangling a History of Hybridization: A Comparison of Phylogenetic Network Methods in Reconstructing Reticulate Evolution in New Zealand Cicadas

Rapid species radiations make hybridization among species more likely. Detecting and reconstructing hybridization is therefore critical for understanding species relationships in many cases. We explored the relative performace of two phylogenetic network methods, SNaQ and PhyNEST, in evaluating the likelihood of proposed past hybridization hypotheses. We used a phylogenomic dataset of over 500 nuclear AHE genes along with mitochondrial genomes to investigate hybridization in a radiation of New Zealand cicada genera Kikihia and Maoricicada. We generated hypotheses for the existence of hybridization events based on patterns of mito-nuclear discordance and hybrid mating signals observed in a previous study. We used the D-statistic to test for the signal from hypothesized hybridization and compared SNaQ and PhyNEST results in reconstructing our hypothesized hybridization events. We found that New Zealand cicadas have an extensive history of reticulate evolution matching predictions based on patterns of mito-nuclear discordance. We also found differences in the biological plausibility of networks inferred between the two network programs, and suggest areas of improvement for network method developers.

evolutionary biology↗

bioRxiv2021

Host-associated microbial diversity in New Zealand cicadas uncovers elevational structure and replacement of obligate bacterial endosymbionts by Ophiocordyceps fungal pathogens

Host-microbe interactions influence eukaryotic evolution, particularly in the sap-sucking insects that often rely on obligate microbial symbionts to provision deficient nutrients in their diets. Cicadas (Hemiptera: Auchenorrhyncha: Cicadidae) specialize on xylem fluid and derive many essential amino acids and vitamins from intracellular bacteria or fungi (Hodgkinia, Sulcia, and Ophiocordyceps) that are propagated via transmission from mothers to offspring. Despite the beneficial role of these symbionts in nutrient provisioning, they are generally not considered to function within the gut where microbiota may play an important dietary role during insect diversification. Here, we investigate the relative impact of host phylogeny and ecology on gut microbial diversity in cicadas by sequencing 16S ribosomal RNA gene amplicons from 197 wild-collected cicadas and new mitochondrial genomes across 38 New Zealand cicada species, including natural hybrids between one species pair. We find a lack of phylogenetic structure and hybrid effects but a significant role of elevation in explaining variation in gut microbiota. Additionally, we provide evidence of Hodgkinia loss with gains of Ophiocordyceps fungal pathogens in all New Zealand cicadas examined that suggests convergent domestications of fungal pathogens. This highlights the macroevolutionary instability of obligate symbiosis and the relative importance of ecology rather than phylogeny for structuring gut microbial diversity in cicadas. ImportanceAn unresolved question in evolutionary biology is how beneficial associations between eukaryotes and microbes impact macroevolutionary patterns. We report substantial data from natural populations that suggest the absence of macroevolutionary impacts from gut microbiota in cicadas. Instead, gut microbial diversity is better explained by elevational variation across an island landscape. Cicadas, like many insects, have obligate nutritional associations with bacteria housed in organs outside of the gut, but we show that these associations seem also to be unstable at macroevolutionary scales. We report evidence for unexpected and widespread replacement of obligate bacteria by a domesticated and formerly pathogenic Ophiocordyceps fungus representing an evolutionarily convergent pattern across the cicada phylogeny.

evolutionary biology↗

bioRxiv2019

Predicting primary production in the southern California Current Ecosystem from chlorophyll, nutrient concentrations, and irradiance

We investigated the processes driving variability in primary productivity in the California Current Ecosystem (CCE) in order to develop an algorithm for predicting primary productivity from in situ irradiance, nutrient, and chlorophyll (chl) measurements. Primary productivity data from seven process cruises of the CCE Long-Term Ecological Research (CCE LTER) program were used to parameterize the algorithm. An initial algorithm was developed using only irradiance to predict chl-specific productivity was found to have model-data misfit that was correlated with NH4+ concentrations. We thus found that the best estimates of primary productivity were obtained using an equation including NH4+ and irradiance: PP/Chl = V0mx(1-exp(-xPAR/V0m)xNH4/(NH4+KS), where PP/Chl is chlorophyll-specific primary production in units of mg C d-1 / mg Chl, PAR is photosynthetically active radiation (units of Ei m-2 s-1), NH4+ is in units of mol L-1, V0m = 66.5 mg C d-1 / mg Chl, = 1.5, and KS = 0.025 mol L-1. We then used this algorithm to compute primary productivity rates for the CCE-P1706 cruise on which in situ primary productivity samples were not available. We compared these estimates to independent productivity estimates derived from protistan grazing dilution experiments and found excellent agreement.

ecology↗