Abstract Detail

Systematics

Mathews, Sarah [1], Murphy, Jordan [2].

Interaction patterns between Australian Loranthaceae species and their host plants at the ordinal Level.

Showy mistletoes are mostly aerial stem hemiparasites of the plant family Loranthaceae (Santalales). They are key participants in diverse interactions with animals, playing an important role in shaping communities by serving as sources of food, shelter, and breeding sites for birds, mammals, and insects. In arid and semi-arid communities of Australia, they have been shown to have positive impacts on diversity and ecosystem function. Underlying these interactions are the evolutionary histories of the parasites, their hosts, pollinators, and dispersers.To begin understanding these interactions, we visualized bipartite networks of mistletoe-host interactions in alluvial plots using the R package ggalluvial. We chose to examine host specificity at the level of mistletoe species to angiosperm clade (order or larger clade), also including one gymnosperm clade, Cupressales. To more easily visualize phylogenetic conservatism in host use, clades were assigned a color, and taxa with significant representation within a clade were assigned a hue of that color. For example, all orders within rosids were assigned hues of blue. 50,125 occurrence and host records for Australian Loranthaceae were downloaded from the Atlas of Living Australia and after cleaning and extracting, 8,894 were retained. Data were sufficient for six of the 10 genera occurring in Australia, Amyema, Amylotheca, Decaisnina, Dendrophthoe, Lysiana, and Muellerina. We included Benthamina and Diplatia in Amyema based on phylogenies from molecular data. Individual plots were made for each genus.One of the most striking patterns to emerge in our mistletoe-host networks was the predominance of rosids serving as mistletoe hosts. In two genera, Amyema and Dendrophthoe, this might reflect the large proportion of records on Acacia (Fabales) or Eucalyptus (Myrtales), the two largest genera in Australia, with about 1000 species each. In two other genera, Amylotheca and Decaisnina, the predominance of rosid hosts reflects more even use by mistletoes of orders across the clade. In Lysiana, rosid hosts were primarily Fabales. Host use by Amylotheca (just two species of tropical and temperate rainforest habitats) was striking in its even use of major clades across angiosperms. Its host use showed the greatest phylogenetic breadth of any loranth genus in Australia. Notably, Amyema, with the largest number of species and the widest distribution inside and outside of Australia, occurred on a much more limited sample of angiosperm diversity. Muellerina had the highest number of records on Proteales and conifers, with two species found only on conifers. Several mistletoe species were found to be host specialists, particularly within Amyema. A greater proportion of mistletoe generalist species was observed in the other genera. Visualizing mistletoe-host relationships at the species-clade level revealed a level of phylogenetic conservatism in host use not apparent in a previously published species-species bipartite network for Australian Loranthaceae. The perspective gained has implications for understanding coevolution, biogeography, and trait evolution.

1 - Louisiana State University, Biological Sciences, 202 Life Sciences Building, Baton Rouge, LA, 70803, United States
2 - Louisiana State University, Department of Biological Sciences, Baon Rouge, LA

Keywords:
Santalales
Loranthaceae
Amylotheca
Amyema
Decaisnina
Dendrophthoe
Lysiana
Muellerina
conifer
parasite
host
bipartite network
interaction
Australia
ggalluvial.

Presentation Type: Oral Paper
Number: SYST II010
Abstract ID:1067
Candidate for Awards:None