Associate Professor
Phone: 903.565.7126
Email: jseal@uttyler.edu
Building: HPR 264
Department: Biology
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Associate Professor
Phone: 903.565.7126
Email: jseal@uttyler.edu
Building: HPR 264
Department: Biology
Teaching Experience
Research Interests
My research has the broad focus of understanding the organismal biology, evolutionary
ecology and ecological impacts of social insect societies and their symbioses. My
work falls into one of three broad areas.
(a) Molecular ecology of symbioses. The main question here is: what are the coevolutionary patterns in specificity among
hosts and symbionts? While there has been much work examining the coevolutionary biology
of fungus-gardening ants over the last few decades, we lack an understanding of host
symbiont relationships between ant hosts and fungal symbionts at the population level.
To this end, my group and I have been examining the molecular ecology of species found
in North America using traditional Sanger markers (Seal et al, 2015, Luiso et al 2020)
and genomic markers: microsatellites (Matthews et al 2020, 2021) and single nucleotide
polymorphisms (SNPs) (Beigel et al (2021). The diversity of fungal lineages in North
America is actually quite high, even though North America is the northern range limit,
the diversity is nearly as high as in tropical latitudes (Luiso et al 2020). Interestingly,
examination of SNPs of ants and fungi indicate 1:1 coevolution; as a result, we think
that models of diffuse coevolution might be poorly applied to the fungus-gardening
ant symbiosis (Beigel et al 2021), generally. Moreover, female ants do not disperse
as far as males; since the fungus is transmitted vertically by females, it is possible
that the expansion rate of fungi is also likely constrained (Matthews et al 2021),
though this hypothesis will need to be tested by fungal genomic markers. Lastly, even
though the symbiosis is characterized by vertical transmission of ants and fungus,
only the bacterial microbiome of the ants appears to be affected by codispersal; whereas
bacteria associated with the fungus appears to have a strong horizontal (environmental)
component (Allert et al, 2017). Future work will involve integrating these findings
on a larger scale, such as how sex biased dispersal impacts expansion rates of ants,
fungus and bacterial associates.
(b) Mechanisms of symbiotic homeostasis. The question here is: what are the organismal properties that are driving the evolutionary
pattern? The broad goal of this theme is to identify, via experimentation (cross-fostering
experiments), the mechanisms critical for the maintenance of symbiotic homeostasis
at ecological and evolutionary scales. In my opinion, publications in this area of
research have been my most important contributions and have largely been responsible
for my success at obtaining funds from NSF (Seal and Tschinkel 2007ac, 2008, Seal
and Mueller 2014, Seal et al 2014 and DeMilto et al 2017). In these papers I have
developed six US fungus-gardening ant species as experimental systems in both laboratory
and field settings. I have found that these six species fall into three main response
categories when forced to grow different species of fungi. This implies that the
stability of naturally-occurring host-symbiont combinations reflect an interaction,
if not a co-evolutionary process that permits the host-symbiont combination to fail
or succeed. Some fail immediately, some sustain growth for several weeks or months
before undergoing irrevocable declines (Seal et al 2014a,b), while others remain stable
for 5 years or more (Seal et al (2014). Because the gardens of unstable combinations
became invaded by weedy, pathogenic species, one hypothesis is that that ant and/or
fungal microbiomes have a role in stabilizing ant-fungal specificity over ecological
and evolutionary time scales (Seal et al 2014).
(c) Ecological Impacts of Symbioses. The main question here is: what is the ecological and evolutionary consequence of the interaction among ants and their symbionts?Without question many symbioses shape and influence their environments (e.g., coral reefs, forests, etc.). This research thread investigates how ants influence the microbial communities, soil organic carbon and ultimately the formation of soils of the southeastern coastal plain of the US (e.g., (Seal and Tschinkel 2006, 2010, Tschinkel and Seal 2016). This is a collaborative project involving research groups in Florida and Yale.
Funding – Most of my work has been funded by the National Science Foundation
Peer Reviewed Publications (since 2013):
*Beigel, K., *Matthews, A.E., Kellner, K., *Pawlik, C., Greenwold, M. & Seal, J.N. (2021) Cophylogenetic analyses of ant-fungal specificity: 'One to one with some exceptions'. Molecular Ecology, doi: 10.1111/mec.16140
*Matthews, A.E., Kellner, K. & Seal, J.N. (2021) Male-biased dispersal in a fungus-gardening ant symbiosis. Ecology and Evolution, 11, 2307-2320.
*Luiso, J., Kellner, K., *Matthews, A. E., Mueller, U. G., & Seal, J. N. (2020). High diversity and multiple invasions to North America by fungi grown by the northern-most Trachymyrmex and Mycetomoellerius ant species. Fungal Ecology, 44, 100878. doi:10.1016/j.funeco.2019.100878
*Matthews, A. E.,* Rowan, C., *Stone, C., Kellner, K., & Seal, J. N. (2020). Development, characterization, and cross-amplification of polymorphic microsatellite markers for North American Trachymyrmex and Mycetomoellerius ants. BMC Research Notes, 13(1), 173. doi:10.1186/s13104-020-05015-3
*Senula, S. F.,* Scavetta, J. T., Banta, J. A., Mueller, U. G., Seal, J. N., & Kellner, K. (2019). Potential Distribution of Six North American Higher-Attine Fungus-Farming Ant (Hymenoptera: Formicidae) Species. Journal of Insect Science, 19(6), 1-11. doi:10.1093/jisesa/iez118
Smith, C.C., Weber, J.N., Mikheyev, A.S., Roces, F., Bollazzi, M., Kellner, K., Seal, J., Mueller, U.G., 2019. Landscape genomics of an obligate mutualism: concordant and discordant population structures between the leafcutter-ant Atta texana and its two main fungal symbiont types. Molecular Ecology 28, 2831-2845.
Kellner, K., M. R. Kardish, J.N. Seal, T. A. Linksvayer, and U. G. Mueller (2018). Symbiont-mediated host-parasite dynamics in a fungus-gardening ant. Microbial Ecology 76(2): 530-543
DeMilto*, A. Rouquette, M., Kellner, K, Mueller, UG and J.N. Seal. (2017) Effects of Substrate, Ant and Fungal Species on Plant Fiber Degradation in a Fungus-gardening Ant Symbiosis. Journal of Insect Physiology. 98: 301-308
Heinze, J., Kellner, K. & Seal, J.N. (2017) Sociality in Ants. Comparative Social Evolution (ed. by P. Abbot and D. Rubenstein). Cambridge University Press.
Tschinkel, W.R. and J.N. Seal. (2016). Bioturbation by the fungus-gardening ant, Trachymyrmex septentrionalis. PLoS One 11(7): e0158920
Seal, J.N., *Brown, L., *Ontiveros, C., *Thiebaud, J. & Mueller, U.G. (2015). Gone to Texas: comparative phylogeography of two Trachymyrmex species along the southeastern coastal plain of North America. Biological Journal of the Linnean Society 114: 689-698
Seal, J.N., Schiøtt, M. & Mueller, U.G. (2014) Ant-fungal species combinations engineer physiological activity of fungus gardens. Journal of Experimental Biology 217: 2540-2547.
Shik, J.Z., Santos, J.C., Seal, J.N., Kay, A., Mueller, U.G. & Kaspari, M. (2014) Metabolism and the rise of fungus cultivation by ants. The American Naturalist 184: 364-373.
Seal, J.N. & Mueller, U.G. (2014) Instability of novel ant-fungal associations suggest that microbial interactions constrain horizontal transfer in higher fungus-gardening ants. Evolutionary Ecology, 28: 157-176.
Kellner, K., Seal, J. & Heinze, J. (2013) Sex at the margins: geographic parthenogenesis in the ant Platythyrea punctata. Journal of Evolutionary Biology, 26: 108-117.
For a comprehensive list of my peer-reviewed publications, please consult my profiles: