Profile photo of Professor Allan G. Ellis

Department of Botany and Zoology

STELLENBOSCH UNIVERSITY

biological interactions

Prof. Allan G. Ellis

I am an evolutionary ecologist studying the evolution of diversity and its ecological and evolutionary consequences. I am fortunate to work in an extraordinary evolutionary laboratory, the hyperdiverse Cape Floristic Region, where the products of the diversification process have accumulated into diverse and complex communities of interacting species. Ultimately I am interested in the mechanisms which 1) determine levels of specialisation of interactions within these communities and 2) drive divergence of interactions/phenotypes across populations within species (and ultimately give rise to new species). Of particular interest to me is the influence of the ever changing biotic environment on diversification. How do (new) species integrate into existing communities? How does their addition alter interaction structure of communities and ultimately selection on all community members? Does accumulation of diversity itself stimulate further diversification in a positive feedback loop?

About

My current research is primarily focused around the evolution of specialization and its consequences in the community context. I am addressing various aspects of this problem using interactions between plants and their pollinators (Gorteria-Megapalpus and Tritoniopsis-nemestrinid fly systems), insect herbivores (Restionaceae-Cephalelus leafhoppers), bacterial symbionts (Acacia-rhizobia) and edaphic environments (Aizoaceae-soils). In each of these systems I use a multi-tiered approach to elucidate mechanisms driving evolution of specialisation and its ecological and evolutionary consequences. I use solid natural history observations and molecular datasets to establish the patterns – phenotypic variation, interaction networks, evolutionary history – and to derive hypotheses about likely mechanisms. Field and greenhouse based experiments are then used to test these mechanistic hypotheses.

 

Ongoing research projects

1. Biotic context and the floral diversification of beetle daisies

I am characterising the biotic landscape gradients that underly the radical diversification of floral form in the beetle daisy (Gorteria diffusa) and experimentally attempting to tease apart the roles of pollinator community composition, pollinator densities, antagonist densities and plant competition environments in driving floral trait evolution.

2. The role of filtering in the evolution of floral specialization

Also in the Gorteria diffusa system, we are examining the influence of selection imposed be effective pollinators, ineffective pollinators and floral antagonists (nectar and pollen thieves) on floral specialization.

3. Floral evolution across geographic mosaics of multiple effective visitors

We are exploring the complex selection gradients underlying floral tube length evolution in the irid, Tritoniopsis revoluta, which is pollinated by nemestrinid flies and Amegilla bees. (with Bruce Anderson)

4. Pollen limitation and pollinator dependence in the Cape flora

It has frequently been argued that Cape plants are strongly pollen limited and this promotes diversification. We are assembling available datasets to test whether this is in fact the case.

5. Structural colour in flowers of the Cape flora

The existence and function of non-pigment based structural colours have long been known from animals, but have only very recently been investigated in plants. We are surveying Cape flowers for structural colour (iridescence and glossiness) and experimentally exploring floral iridescence and its functions in Spiloxene capensis. (with Heather Whitney)

6. Linking dispersal in space and time and pollination dynamics of Namaqua daisies

We are studying variability of dispersal and dormancy traits across broad geographic areas for many daisy species to gain understanding of the influence of environmental predictability and reproductive traits (breeding system, pollination systems) on the evolution of dispersal in space and time. (with Bruce Anderson)

7. Evolution of specialization and community assembly of restio leaf-hoppers

We are using the Restionaceae and their insect herbivores to take a first look at plant-insect diversity relationships, insect community (network) structure and the evolution of specialization in insect herbivores in the Cape. Insect ecology and evolution in the Cape is very poorly known in comparison to the plants. We don’t, for instance, know how the remarkable plant diversification in the Cape has influenced insect evolution. (with Bruce Anderson, Jaco Le Roux and Peter Linder)

8. Rhizobia-legume interaction networks in an invasion context

We are characterizing legume-rhizobium interaction networks in the Cape and investigating the integration into and influence of invasive legumes on these underground mutualisms. (with Jaco le Roux)

9. Evolution of minutism and its effects on plant diversification

We are examining the influence of plant size on diversification of the succulent Karoo flora, with a focus on experimentally assessing the influence of size on neutral and adaptive aspects of divergence. (with Tony Verboom)

Current Research

Post-doctoral fellows:

Dr Willem Augustyn

“Evolutionary drivers of temporal and spatial host-use patterns in restio leafhoppers Cephalelus Percheron (Cicadellidae: Cephalelini)” (with B Anderson)

 

Dr Florian Boucher

"The role of plant size in rates of diversification"

 

PhD students:

Jurene Kemp

“Pollinator specialization resulting from the filtering of less effective pollinators”

 

Jan-Hendrik Keet (co-supervised)

“Understanding the biodiversity impacts of invasive species: Investigating changes in below- and above-ground mutualistic networks in response to invasions” (with JJ Le Roux, C Hui)

 

M.Sc. students:

Seth Musker (UCT)

“The role of minutism as a driver of diversification in the succulent karoo flora of South Africa” (with GA Verboom)

Post-docs & Students

Contact me directly:agellis@sun.ac.za

Opportunities

for citation metrics see Google Scholar

 

for pdfs see Research Gate or contact me directly

 

 

2017

 

Boucher FC, GA Verboom, S Musker & AG Ellis. 2017. Plant size: a key determinant of diversification? New Phytologist. doi:10.1111/nph.14697.

 

De Jager. ML & AG Ellis. 2017. Evolutionary history of a keystone pollinator parallels the biome occupancy of angiosperms in the Greater Cape Floristic Region. Molecular Phylogenetics and Evolution 107: 530-537

 

Augustyn WJ, B Anderson, JF van der Merwe & AG Ellis. 2017. Spatial turnover in host-plant availability drives host-associated divergence in a South African leafhopper (Cephalelus uncinatus). BMC Evolutionary Biology 17(1):72.

 

Kemp JE, HP Linder & AG Ellis. 2017. Beta diversity of herbivorous insects is coupled to high species and phylogenetic turnover of plant communities across short spatial scales in the Cape Floristic Region. Journal of Biogeography 44: 1813-1823. doi:10.1111/jbi.13030

 

Kemp JE & AG Ellis. 2017.  Significant local-scale plant-insect species richness relationship independent of abiotic effects in the temperate Cape Floristic Region biodiversity hotspot. PLoS ONE 12(1): e0168033. doi:10.1371/journal.pone.0168033

 

Kemp JE, Evans, DM, Augustyn, WJ and AG Ellis. 2017. Invariant antagonistic network structure despite high spatial and temporal turnover of interactions. Ecography 40:1-10. doi:10.1111/ecog.02150

 

Le Roux JJ, C Hui, JH Keet & AG Ellis. 2017. Co‐introduction vs ecological fitting as pathways to the establishment of effective mutualisms during biological invasions. New Phytologist 215: 1354-1360. doi: 10.1111/nph.14593.

 

Le Roux JJ, JH Keet, B Mutiti & AG Ellis. 2017. Cultivation may not dramatically alter rhizobial community diversity or structure associated with rooibos tea (Aspalathus linearis Burm. F.) in South Africa. South African Journal of Botany 110:87-96.

 

Keet J-H, AG Ellis, C Hui & JJ Le Roux. 2017. Legume–rhizobium symbiotic promiscuity and effectiveness do not affect plant invasiveness. Annals of Botany 119 (8): 1319-1331. doi:10.1093/aob/mcx028

 

 

2016

 

Rodger JG & AG Ellis. 2016. Distinct effects of pollinator dependence and self-incompatibility on pollen limitation in South African biodiversity hotspots. Biology Letters 12: 20160253.

 

Augustyn WJ, B Anderson & AG Ellis. 2016. Experimental evidence for fundamental, and not realized, niche partitioning in a plant–herbivore community interaction network. Journal of Animal Ecology, 85(4): 994-1003

 

Le Roux JJ, NR Mavengere & AG Ellis. 2016. The structure of legume-rhizobium interaction networks and their response to tree invasions. AoB Plants 8: plw038. doi:10.1093/aobpla/plw038

 

De Waal C, B. Anderson & AG Ellis. 2016. Dispersal, dormancy and life history trade-offs at the individual-, population- and species-level in southern African Asteraceae. New Phytologist 210: 356–365

 

 

2015

 

De Waal C, B. Anderson & AG Ellis. 2015. Relative density and dispersion pattern of two southern African Asteraceae affect fecundity through heterospecific interference and mate availability, not pollinator visitation rate. Journal of Ecology 103: 513-525.

 

Gildenhuys E, AG Ellis, SP Carroll & JJ Le Roux. 2015. From the Neotropics to the Namib: evidence for rapid ecological divergence following extreme long-distance dispersal. Botanical Journal of the Linnean Society. DOI: 10.1111/boj.12334

 

Gildenhuys E, AG Ellis, SP Carroll & JJ Le Roux. 2015. Combining natal range distributions and phylogeny to resolve biogeographic uncertainties in balloon vines (Cardiospermum, Sapindaceae). Diversity and Distributions 21 (2), 163-174. DOI: 10.1111/ddi.12261

 

Pfaff MC, Branch GM, Fisher JL, Hoffman V, Ellis AG, JL Largier. 2015. Delivery of marine larvae to shore requires multiple sequential transport mechanisms. Ecology 96(5): 1399–1410.

 

 

2014

 

Ellis AG, SF Brockington, ML de Jager, G Mellers, RH Walker & BJ Glover. 2014. Floral trait variation and integration as a function of sexual deception in Gorteria diffusa. Philosophical Transactions of the Royal Society B 369: 20130563

 

De Jager ML & AG Ellis. 2014. How the costs of deception affect learned resistance. Proc. Roy. Soc. B. 281: 20132861. http://dx.doi.org/10.1098/rspb.2013.2861

 

De Jager ML & AG Ellis. 2014. Floral polymorphism and the trade-offs of attracting pollinating and florivorous insects. Annals of Botany 113:213-222. doi:10.1093/aob/ mct189

 

Ellis AG, T van der Niet, SD Johnson, GA Verboom & HP Linder. 2014. Speciation and extinction in the Greater Cape Floristic Region. In: N Allsopp, JF Colville, GA verboom (Eds). Fynbos:Ecology, Evolution and Conservation  of a Megadiverse Region. Oxford University Press. P119-141.

 

Anderson B, AG Ellis, J Rodger, A Pauw, J Midgley, N Allsopp & SD Johnson. 2014. Biotic interactions. In: N Allsopp, JF Colville, GA verboom (Eds). Fynbos:Ecology, Evolution and Conservation  of a Megadiverse Region. Oxford University Press

 

Anderson B., P Ros, TJ Wiese & AG Ellis. 2014. Intraspecific divergence and convergence of floral tube length in specialized pollination interactions. Proc. R. Soc. B 281, 20141420

 

De Waal C, JG Rodger, B Anderson & AG Ellis. 2014. Selfing ability and dispersal are positively related, but not affected by range position: a multispecies study on southern African Asteraceae. Journal of Evolutionary Biology 27: 250-259.

 

Mavengere NR, AG Ellis & JJ Le Roux. 2014. Burkholderia aspalathi sp. nov., isolated from root nodules of the South African legume Aspalathus abietina Thunb. International Journal of Systematic and Evolutionary Microbiology 64: 1906-1912.

 

 

2013

 

De Jager ML & AG Ellis. 2013. The influence of pollinator phylogeography and mate preference on floral divergence in a sexually deceptive daisy. Evolution 67: 1706–1714

 

Stangberg F, AG Ellis & AA Anderberg. 2013. Evolutionary relationships in Gorteria: a re-evaluation. TAXON 62(3) 537-549.

Augustyn WJ, B Anderson, M Stiller & AG Ellis. 2013. Specialised host-use and phenophase tracking in restio leafhoppers, Cephalelus (Cicadellidae: Cephalelini) in the Cape Floristic Region. Journal of Insect Conservation 17 (6): 1267-1274.

 

Gildenhuys E, AG Ellis, SP Carroll & JJ Le Roux. 2013. The ecology, biogeography, history and future of two globally important weeds: Cardiospermum halicacabum Linn. and C. grandiflorum Sw. NeoBiota 19: 45–65. doi: 10.3897/neobiota.19.5279

 

Blignaut M, AG Ellis, JJ Le Roux. 2013. Towards a transferable and cost-effective plant AFLP protocol. PLoS One 8(4) : e61704

 

 

2012

 

De Jager ML & AG Ellis. 2012. Gender specific preference for floral traits. Functional Ecology 26:1197-1204.

 

Ellis AG & SD Johnson. 2012. Lack of floral constancy by bee fly pollinators: implications for ethological isolation in an African daisy. Behavioral Ecology 23 (4), 729-734

 

Whitney HM, SA Rands. NJ Elton & AG Ellis. 2012. A technique for measuring petal gloss, with examples from the Namaqualand flora. Plos One: 7 (1): e29476

 

Ellis AG and B Anderson. 2011. Pollinator mediated floral divergence in the absence of pollinator shifts. In: Patiny S (Ed). Evolution of plant-pollinator relationships. Cambridge University Press. P237-262.

 

 

2011

 

De Jager ML, LL Dreyer & AG Ellis. 2011. Do pollinators influence the assembly of flower colours within plant communities? Oecologia. 166: 543-553.

 

Ros P, AG Ellis & B Anderson. 2011. Maintenance of sympatric floral tube-length variation in a Cape irid. Biological Journal of the Linnean Society 104: 129-137.

 

Johnson SD, CI Peter, AG Ellis, E Boberg, C Botes; & T van der Niet. 2011. Diverse pollination systems of the twin-spurred orchid genus Satyrium in African grasslands. Plant Systematics and Evolution. 292: 95-103.

 

Ellis AG. 2011. Deserts as laboratories of evolution. South African Journal of Science 107: 9-10.

 

Whitney HM, Glower BJ, Walker R & AG Ellis 2011 The contribution of epidermal structure to flower colour in the South African flora. Curtis’s Botanical Magazine 28 (4): 349-371

 

Duncan G & AG Ellis 2011. 723 Gorteria diffusa. Curtis’s Botanical Magazine 28 (4): 341-348.

 

Duncan G & AG Ellis 2011. 716 Spiloxene capensis. Curtis’s Botanical Magazine 28 (4): 260-268.

 

 

2010

 

Ellis AG & SD Johnson. 2010. Floral mimicry enhances pollen export: the evolution of pollination by sexual deceit outside of the Orchidaceae. American Naturalist. 176 (5): E143-E151.

 

Ellis AG & SD Johnson. 2010. Gender differences in the effects of floral spur length manipulation on fitness in a hermaphrodite orchid. International Journal of Plant Sciences 171(9): 1010-1019.

 

Anderson B, JS Terblanche & AG Ellis. 2010. Predictable patterns of trait mismatches between interacting plants and insects. BMC Evolutionary Biology 10:204.

 

 

Before 2010

 

Thomas MM, BJ Glover, AG Ellis, V. Savolainen and PJ Rudall. 2009. Development of a complex floral trait: The pollinator-attracting petal spots of the beetle daisy, Gorteria diffusa (Asteraceae). American Journal of Botany 96(12): 2184-2196.

 

de Merxem DG, B Borremans, ML de Jager, T Johnson, M Jooste, P Ros, RD Zenni, AG Ellis & B Anderson. 2009. The importance of flower visitors not predicted by floral syndromes. South African Journal of Botany 75: 660-667.

 

Ellis AG & SD Johnson. 2009. The evolution of floral variation without pollinator shifts in Gorteria diffusa (Asteraceae). American Journal of Botany 96(4): 793-801.

 

Dumri K, L Seipold, J Schmidt, G Gerlach, S Dötterl, AG Ellis & LA Wessjohann. 2008. Non-volatile floral oils of Diascia spp. (Scrophulariaceae). Phytochemistry 69: 1372-1383.

 

Ellis AG , AE Weis & B Gaut. 2007. The spatial scale of local adaptation and population genetic structure in a miniature succulent, Argyroderma pearsonii. New Phytologist 174 (4): 904-914.

 

Johnson SD, AG Ellis & S Dotterl. 2007. Specialization for pollination by beetles and wasps: the role of lollipop hairs and fragrance in Satyrium microrrhynchum (Orchidaceae). American Journal of Botany 94 (1): 47-55.

 

Ellis AG, AE Weis & B Gaut. 2006. Evolutionary radiation of “stone plants” in the genus Argyroderma: unravelling the effects of landscape, habitat and flowering time. Evolution 60(1): 39-55.

 

Ellis AG & AE Weis. 2006. Coexistence and differentiation of “flowering stones”: the role of local adaptation to soil microenvironment. Journal of Ecology 94: 322-335.

 

von Hase A, RM Cowling & AG Ellis. 2006. Petal movement in Cape wildflowers protects pollen from exposure to moisture. Plant Ecology 184: 75-84.

 

Franke DM, AG Ellis, M Dharjwa, M Freshwater, M Fujikawa, A Padron & AE Weis. 2006. A steep cline in flowering time for Brassica rapa in southern California: Population-level variation in the field and greenhouse. Intl. J of Plant Sciences 167(1): 83-92.

 

Desmet PG, RM Cowling, AG Ellis & RL Pressey. 2002. Integrating biosystematic data into conservation planning: perspectives from Southern Africa’s succulent Karoo. Systematic Biology 51(2): 317-331.

 

Ellis AG & SD Johnson. 1999. Do pollinators determine hybridization patterns in sympatric Satyrium (Orchidaceae) species? Plant Systematics and Evolution 219: 137-150.

 

Cowling RM, RL Pressey, AT Lombard, PG Desmet and AG Ellis. 1999. From representation to persistence: requirements for a sustainable system of conservation areas in the species-rich mediterranean-climate desert of southern Africa. Diversity and Distributions 5: 51-71.

 

Desmet PG, AG Ellis and RM Cowling. 1998. Speciation in the Mesembryanthemaceae. ALOE 35 (2): 38-43.

 

Ellis AG and JJ Midgley. 1996. A new plant-animal mutualism involving a plant with sticky leaves and a resident hemipteran insect. Oecologia 106: 478-481.

 

Johnson SD, AG Ellis, PJ Carrick, A Swift, S van Rensburg, N Horner and WJ Bond. 1993. Moth pollination and rhythms of advertisement and reward in Crassula fascicularis (Crassulaceae). South African Journal of Botany 59(5): 511-513.

 

 

 

 

 

Publications

Photo: Caroli Diener

Profile photo of Professor Allan G. Ellis