Social insect research in   Uppsala, Sweden

The Uppsala social insect group works in the population genetics laboratory in the Department of Conservation Biology and Genetics, the University of Uppsala. The laboratory has three major research areas: 1) evolution and population genetics of social insects, 2) genetics of small and fragmented populations, and 3) molecular evolution. The projects in all these areas include both theoretical modelling and empirical studies of natural populations. Lab work is mainly based on DNA microsatellites and DNA sequences. We have developed microsatellite primers for a number of organisms, including insects, vertebrates and plants, and use microsatellite markers in our studies of social insect colonies and small populations. The Uppsala social insect group makes a special contribution to the TMR-network by its expertise on the application of DNA techniques and has hosted a workshop on genetic methods in October 1998. The research is supported by grants from the Swedish Natural Sciences Research Council and from private foundations.

The population genetics laboratory has (situation in the spring 1999) three faculty positions, four post docs and ten PhD students. The other research groups in the department have also a strong emphasis in evolutionary studies. The University of Uppsala has in recent years strongly developed a new Evolutionary Biology Centre, and the Department of Conservation Biology and Genetics is part of that centre and will move to new laboratories in early 2000. The centre is particularly strong in the areas of molecular ecology, molecular evolution, behavioural ecology and systematics.

•   Dr. Pekka Pamilo (professor)
•   Dr. Perttu Seppä (EU network post-doc)
•   Dr. Ignacio Fernandez Escudero (EU-Marie Curie post-doc)
•   Peter Thorén (postdoc)
•   Pia Gertsch (PhD student)
•   Anna Goropashnaja (PhD student)
•   Niclas Gyllenstrand (PhD student)
•   Cia Olsson (technician)

•   Dr Robert Paxton (postdoc, at present in Tübingen, Germany)
•   Dr Danqing Zhu (postdoc, at present in Sydney, Australia)

• Polyandry and intracolonial conflicts:
  
  The studies of both annual (Bombus, Dolichovespula, Vespa, Vespula) and perennial colonies (Camponotus, Lasius, Formica, Proformica) aim to examine the causes leading to evolution of polyandry and the consequences of polyandry that reduces the genetic relatedness among colony members. The monogynous and polyandrous bumblebees and social wasps offer excellent possibilities for testing the hypotheses of split sex ratios and worker policing. The social wasps show a wide range of mating numbers, and the evolution of the mating behaviour is studied in a phylogenetic context. The studies on ants add the important aspects of diploid male production and colony survival. In addition to the empirical studies, we work with theoretical models of polyandry, aiming to examine the theoretical basis of its evolution and of its consequences.



• Reproductive skew and budding in Proformica longiseta:
  
  Proformica longiseta is an endemic ant species in Spain, and the colonies have normally one queen or a few queens. The colonies are small and the density is locally high. The females are wingless which restricts their dispersal. We examine the sociogenetic organisation of colonies, including studies of polyandry of females, reproductive skew among coexisting queens, and whether colony budding follows kin lines.



• Spatial genetic structure of ant populations:
  
  We study the effects of sociality on the spatial genetic structure and speciation at two levels that we can call ecological and phylogenetic. At the ecological level, we will test whether species with highly polygyne societies show large genetic differentiation among populations, and whether polygyne and monogyne social forms within a species are genetically differentiated from each other. At the phylogenetic level we test whether the species with polygyne societies have evolved independently from monogyne ancestors, or whether the major transition in the social form has occurred only once in the mound-building wood ants. The main species in this project are ants from the genera Formica, including the common mound-building wood ants. The genus includes several pairs of sibling species, one of which has monogynous and the other polygynous colonies. Some Formica species show social polymorphism and have two different colonial types, type M with monogynous and monodomous colonies and type P with polygynous and polydomous colonial networks. In the genetic studies we examine the gene flow within and between the social types and try to distinguish between male and female dispersal. The colonial structure and the level of gene flow influence several characteristics of the populations. Our aim within the framework of the EU network is to examine the connection of the social and population structure to the role of diseases and parasites.



• Phylogeography of Formica ants:
  
  Many Formica species are associated to coniferous trees, as they use needles to construct nest mounds and use aphids living in trees. As the species have long-living colonies and (based on our genetic studies) restricted dispersal rates, it can be predicted that the post-glacial colonization histories can be detected in the patterns of genetic differentiation of populations. This project addresses questions on basic characteristics of intraspecific biodiversity and contributes in our knowledge on the genetic differentiation of ant populations, the role of adaptation in morphological differentiation, and the putative role of sociality in speciation process. The results form also a basis to understand how the ant biodiversity is affected particularly by the modern forestry.

• Berg L, Lascoux, M & Pamilo, P (1998) The infinite island model with sex-differentiated gene flow. Heredity 81:63-68
• Beye M, Neumann P, Chapuisat M, Pamilo P & Moritz RFA (1998) Nestmate recognition and the genetic relatedness of nests in the ant Formica pratensis. Behav Ecol Sociobiol 43:67-72
• Crozier RH & Pamilo P (1996) Evolution of social insect colonies. Oxford Series of Ecology and Evolution, Oxford Univ Press. 306 pp
• Fernandez Escudero I & Tinaut A (1998) Heat-cold dialectic in the activity of Proformica longiseta, a thermophilous ant inhabiting a high mountain (Sierra Nevada, Spain). Int J Biometeor 41:175-182
• Gadau J, Gertsch PJ, Heinze J, Pamilo P & Holldobler B (1998) Oligogyny by unrelated queens in the carpenter ant, Camponotus ligniperdus. Behav Ecol Sociobiol (in press)
• Gertsch P & Fjerdingstad E (1997) Biased amplification and the utility of spermatheca-PCR for mating frequency studies in Hymenoptera. Hereditas 126:183-186
• Laurila A & Seppä P (1998) Multiple paternity in the common frog (Rana temporaria): genetic evidence from tadpole kin groups. Biol J Linn Soc 63: 221-232
• Pamilo P & Crozier RH (1997) Population biology of social insect conservation. - Mem Mus Vic 56:411-419
• Pamilo P, Gertsch P, Thorén P & Seppä P (1997). Molecular population genetics of social insects. Annu Rev Ecol Syst 28:1-25
• Paxton RJ, Thorén PA, Tengö J, Estoup A & Pamilo P (1996) Mating structure and nestmate relatedness in a communal bee Andrena jacobi (Hymenoptera, Andrenidae), using microsatellites. Mol Ecol 5:511-519
• Peuhkuri N & Seppä P (1998) Do three-spined sticklebacks go to school with their kin? Ann Zool Fenn 35: 21-27
• Seppä P & Gertsch P (1996) Genetic relatedness in the ant Camponotus herculeanus. A comparison of estimates from allozyme and DNA microsatellite markers. Ins Soc 43:235-243
• Thorén, PA (1998) Mating structure and nestmate relatedness in primitively social Hymenoptera as revealed by microsatellites. PhD thesis.
• Thorén PA, Paxton RJ, & Estoup A (1995) Unusually high frequency of (CT)n and (GT)n microsatellite loci in a yellowjacket wasp, Vespula rufa (L.) (Hymenoptera: Vespidae). Ins Mol Biol 5:141-148