Rebecca
N. JohnsonRebecca
N. Johnson
My early research work involved population genetic studies of Queensland fruit flies (Bactrocera tryoni), a major insect pest of fruit crops, particularly citrus, in Australia.
Following this, for my Ph.D. work, I constructed a molecular phylogeny of all known weaver-ant genera (some represented by multiple species, many of which are found in Australia), in order to place individual genera relative to one and other within the sub-family Formicinae. Weaving is regarded as a highly complex behaviour representing extreme cooperation between individuals. In addition to this complex lifestyle, it appears that all genera in which weaving occurs have lost their metapleural-gland opening. The metapleural-gland is considered a diagnostic trait for the Formicidae (all extant ants!) and is thought to function in an antibiotic and antifungal capacity. Consequently, our phylogeny was a tool with which to analyse the number of times weaving has evolved, and whether there is a functional correlation between metapleural-gland loss and weaving.
As a complement to my phylogenetic studies, I worked on the population genetics of a northern Australian species of weaver ant, Polyrhachis doddi, which has an interesting colony structure, in addition to its intriguing arboreal-weaving lifestyle. I considered P. doddi to be a good representative species of weaver ‘of intermediate complexity’, for which to analyse colony structure using microsatellite markers.
Currently, I am searching for the genetic region that controls dance behaviour in honeybees (Apis mellifera). Honeybees have a highly evolved and unique communication system known as 'dance language'. Bees use dance as a form of communicating distance and direction of potential food sources or nest sites.
There is well documented variation in dance dialects (i.e. at what distance one dance type changes into the next most complex) between different races of Apis mellifera. We are exploiting the difference that exists between two races of Apis mellifera by creating an F1 cross and an F2 backcross, and analysing the dance behaviour of the resultant progeny.
I am using current molecular techniques, such as Subtractive Hybridisation, Differential Expression, Microarray and RT PCR, to identify candidates that may be controlling this behaviour through differential expression.
Crozier R.H., Oldroyd B.P., Tek Tay W., Kaufmann B.E., Johnson R.N., Carew M.E., Jennings K.M. (1997) Molecular advances in understanding social insect population structure. Electrophoresis ,18,1672-1675.
Johnson, R.N., Oldroyd, B.P., Barron, A.B. and Crozier, R.H., Genetic control of the honey bee (Apis mellifera) dance language: Segregating dance forms in a backcrossed colony. (2002) Journal of Heredity, 93(3), 170-173
Johnson, R.N., Agapow, P-M., Crozier, R.H., A tree-island approach to inferring phylogeny in the ant subfamily Formicinae, with especial reference to the evolution of weaving (submitted to Molecular Phylogenetics and Evolution)
Johnson, R.N., Oldroyd, B.P. and Crozier, R.H., Molecular characterisation of the honeybee ‘waggle dance’ locus (in preparation)
Johnson, R.N., Crozier, R.H., The evolution of multiple-queen ant colonies, insights from a facultatively polygynous species, Polyrhachis doddi (in preparation)
Johnson, R.N., Agapow, P-M., Crozier, R.H., 2002. A tree-island approach to inferring phylogeny in the ant subfamily Formicinae, with especial reference to the evolution of weaving. Pp In Proceedings of the XIVth International Congress of the IUSSI, Sapporo
Johnson, R.N., Oldroyd, B.P., Barron, A.B. and Crozier, R.H., 2000. Examining the Genetic control of dance in honeybees (Apis mellifera).Pp. 885 In L. Gazzoni, ed. XXIth International Congress of Entomology Abstracts, Foz do Iguassu, Brazil.
Johnson, R.N. and Crozier, R.H., 2000. Application of molecular genetic techniques for a better understanding of evolution in the social insects. Pp. 551 In L. Gazzoni, ed. XXIth International Congress of Entomology Abstracts, Foz do Iguassu, Brazil.
Johnson, R.N., Beckenbach, A.T, Robson, S.K., Chiotis, M. and Crozier, R.H., 1998. A molecular phylogeny of the weaver ants. Pp 235 in M.P. Schwartz and K. Hoogendoorn, eds. Social Insects at the turns of the millenium. Proceedings of the XIIIth International Congress of the IUSSI, Adelaide.
Johnson, R.N. and Crozier, R.H., 1998. Population viscosity and multi-nest colonies in the ant, Polyrhachis doddi. Pp 33 in J. Sved, ed. Genetics Society of Australia 45th Annual conference, Sydney Australia.
Johnson, R.N. and Crozier, R.H., 1997. Population structure of the weaver ant Polyrhachis doddi using microsatellite DNA markers. Pp 40 in H.M. Stace, ed. Genetics Society of Australia 44th Annual conference, Perth Australia.
XXIth International Congress of Entomology “Application of molecular genetic techniques for a better understanding of evolution in the social insects”, Iguassu Falls, Brazil, August 2000
Tropical Biology seminar series 2001, “Dances with bees: a molecular investigation into the dance language of Apis mellifera” James Cook University, Townsville campus, May 2001
Tropical Biology seminar series 2002, “A molecular phylogeny of the weaver ants: search for a global optimum using a random-tree approach” James Cook University, Townsville campus, May 2002
XIVth International Congress of the IUSSI, Sapporo Japan, July 2002
Australasian Evolution Society meeting, Melbourne Australia, July 2001
VIIIth International Behavioural Ecology Congress, Zurich Switzerland, August 2000
XIIIth International Congress of the IUSSI, Adelaide Australia, December 1998-99
Genetics Society of Australia 45th Annual conference, Sydney Australia, July 1998
Society for the Study of Evolution, Annual meeting, Vancouver Canada, June 1998
Genetics Society of Australia 44th Annual conference, Perth Australia, September 1997
XIVth International Congress of the IUSSI, Sapporo Japan, July 2002
XXIth International Congress of Entomology, Iguassu Falls Brazil, August 2000
VIth International Behavioural ecology congress, Canberra Australia, September 1996.
Genetics Society of Australia 43rd Annual conference, Melbourne Australia, July 1996. Awarded an honourable mention for best poster competition