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Diana M. Percy
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Contact Details: I am currently
based at |
The legume-feeding psyllid, Arytinnis nigralineata (male), with a parasitic mite |
Go to: psyllid Home page, psyllid acoustics, psyllid morphology, Macaronesian island psyllids, Pacific island psyllids, psyllids of economic importance, psyllid/host plant database, psyllid bibliography
My research interests
My research has focused on the interactions between plants and insects. I am interested in the evolutionary and ecological dynamics of these interactions, including parasitic phytophagous and mutualistic pollination systems. The other main focus of my research is the radiation and diversification of species on islands. Together, the biogeographic patterns of speciation on islands and the ecological analysis of interacting groups has proved an exciting way to investigate evolution and natural selection.
I have undertaken postdoctoral research on the acoustic signals of Australian psyllids (Psylloidea, Hemiptera), and I have employed a phylogenetic framework (based on molecular data) to investigate the evolutionary role and apparent phylogenetic signal of acoustic characters. I have recorded an astounding diversity of 'songs' from 27 species in 13 genera of Australian psyllids. By selecting a complex of morphologically similar taxa (cryptic species) that occur on closely related host plants, I have assessed the congruence between geographic population structure, acoustic characters and host plant habitat. I have used playback experiments to test female receptivity to conspecific and heterospecific male calls from different hosts. This work, together with an ongoing molecular phylogeny, will be used to investigate the evolutionary patterns of psyllid acoustics (Percy et al. in review, Percy & Clarke in prep.). These analyses represent the first systematic study of acoustic diversity in the Psylloidea. Recently, I have submitted (together with David Marshall and Kimberly Bostwick) a proposal to organize a symposium at the next Joint Meetings of the American Society of Naturalists, Society for the Study of Evolution, and Society of Systematic Biologists (2003). The topic of the symposium is ‘Evolution and phylogenetic utility of sexually selected signals’.
During May-August 2002, I visited eastern and western regions of the Pacific to survey the triozid psyllid diversity on different islands, to determine host associations and to collect material for my proposed research on the phylogenetics of the Pacific triozids, and the mechanisms of speciation in the Hawaiian Metrosideros-feeding group. Partial mitochondrial sequence data sets have now been generated for many of these taxa.
My PhD
research focused on psyllids found on hosts in the legume tribe Genisteae.
I combined phylogenetic analysis of both the plant and insect groups to
explore the possibility of synchronous, coevolutionary lineages. I also
explored the origins and maintenance of host specificity, and the effects
of habitat alteration on insect-plant dynamics. The central Macaronesian
islands and adjacent continental regions were extensively surveyed to
determine the possible origins and progenitors of the island plant and
psyllid groups. My phylogenetic analysis based on three mitochondrial
gene regions of the Genisteae-feeding psyllids (Arytaininae) found only
one of the three genera to be monophyletic. This genus represents a dramatic
island radiation. Over half the psyllids collected were new species, and
I undertook a taxonomic revision in which I described one new genus, with
descriptions, keys and illustrations for 17 new species and nymphal stages
for a further 15 species (Percy 2003a , Percy
2002).
I have used both molecular and morphological phylogenetic methods to assess
species relationships in the Genisteae-feeding psyllids and their legume
hosts, and to determine the number of colonizations of the Canary Islands
and subsequent inter-island dispersal (Percy 2003b).
I used three mitochondrial genes, cytochrome oxidase I, cytochrome oxidase
II, and the small subunit ribosomal RNA in the molecular analyses of the
insects. For the morphological analysis, both quantitative and qualitative
characters from adult and larval stages were incorporated in a cladistic
analysis. The inclusion of the continental psyllid species enabled me
to determine not only the number of island colonizations, but the possible
historical host associations and subsequent host switching and host shifts
that has produced the apparent pattern of host preference, and host sharing
by multiple psyllid species observed today. To investigate relationships
among the host plants, I constructed a molecular phylogeny for the legume
host group using the nuclear internal transcribed spacer, to investigate
evolutionary patterns in three genera of Macaronesian Genisteae (Percy
& Cronk 2002). With the construction of both legume and psyllid
phylogenies, I was able to use new techniques for dating molecular phylogenies
to assess the extent of contemporaneous speciation in psyllids and their
legume hosts (Percy et al. 2004).
My MSc course (at the Royal Botanic Garden Edinburgh) covered a wide range of plant science subjects including both morphological and molecular studies, classifications using computer databases and computer generated keys, phenetic and cladistic analyses, biodiversity, ecology, and the management and current roles of herberia and botanic gardens. My dissertation focused on the evolution of dioecious breeding systems in two endemic species (Petrobium arboreum, Compositae and Nesohedyotis arborea, Rubiaceae) on the Atlantic Ocean island of St Helena, with reference to the association between plant breeding systems and conservation (Percy & Cronk 1997)
Percy, D.M., Page, R.D.M. & Cronk, Q.C.B. (2004) Plant-insect interactions: double-dating associated insect and plant lineages reveals asynchronous radiations. [Invited paper as part of the ‘Untangling Coevolution’ symposium held at the 2001 Evolution meeting, Illinois]. Systematic Biology 53, 120-127. pdf (233 kb)
Percy, D.M. (2003a) Legume-feeding psyllids (Hemiptera, Psylloidea) of the Canary Islands and Madeira. Journal of Natural History 37, 397-461. pdf (1980 kb)
Percy, D.M. (2003b) Radiation, diversity and host plant interactions among island and continental legume-feeding psyllids. Evolution 57, 2540-2556. pdf (1599 kb)
Percy, D.M. (2003c) Book review, ‘Tangled Trees: Phylogeny, Cospeciation, and Coevolution’, ed. R.D.M. Page. Invertebrate Systematics 17, 359-360. pdf (34 kb)
Percy, D.M. (2002) Distribution patterns and taxonomy of some legume-feeding psyllids (Hemiptera; Psylloidea) and their hosts from the Iberian Peninsula, Morocco and Macaronesia. Journal of Insect Systematics and Evolution 33, 291-310. pdf (1054 kb)
Percy, D.M. & Cronk, Q.C.B. (2002) Different fates of island brooms: contrasting evolution in Adenocarpus, Genista and Teline (Genisteae, Leguminosae) in the Canary Islands and Madeira. American Journal of Botany 89, 854-864. pdf (207 kb)
Percy, D. & Oromí, P. (2001) Hemiptera, Psyllidae. Checklist of Canary Island psyllids in Lista de Especies Silvestres de Canarias. p.196. Gobierno de Canarias. Tenerife.
Percy, D.M. &
Cronk, Q.C.B. (1997) Conservation in relation to mating systems in Nesohedyotis
arborea
(Rubiaceae), a rare endemic tree from St Helena. Biological Conservation
84, 135-145. pdf
(1023 kb)
Percy, D.M., Taylor, G.S. & Kennedy, M. (in review) Psyllid communication: acoustic diversity, mate recognition and selection. Biological Journal of the Linnean Society.
Percy, D.M. & Day, M.F. (in review) Observations of unusual acoustic behaviour in two Australian leafhoppers (Hemiptera; Cicadellidae). Journal of Natural History.
Percy, D.M. & Clarke, G.M. (in prep.) Acoustic signals and phylogeography of cryptic species of Eucalyptus-feeding psyllids (Hemiptera; Psylloidea; Spondyliaspidinae).
Keller, M. & Percy, D.M. (in prep.) The courtship sounds of Cotesia rubecula (Hymenoptera: Braconidae). Journal of Insect Behavior.
Go to: psyllid Home page, psyllid acoustics, psyllid morphology, Macaronesian island psyllids, Pacific island psyllids, psyllids of economic importance, psyllid/host plant database, psyllid bibliography
All images, unless otherwise noted, are copyright © Diana M. Percy
Created 2002. Updated 20/01/2005. Return to top of page
Pacific island psyllids
psyllids of economic importance
psyllid bibliography
