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This chapter provides information on the obligate mutualism between figs (Ficus carica) and its pollinator, the fig wasp (Blastophaga psenes). Some notes on the pollination biology of wild and cultivated figs are presented and details on some other fig pollinators are highlighted.

A small fig tree has been misidentified as Ficus orthoneura for a long time. However, morphologically it is distinct from F. orthoneura and F. hookeriana. Typical are the ellipsoid, puberulous receptacle and caducous basal bracts. Leaf anatomy shows a multiple epidermis with the cells in the inner layer much larger than in the outer layer and thus both layers resemble an epidermis with a separate hypodermis. The abaxial cuticle is strongly sculptured, the palisade layer shows some long subdivided cells, and enlarged lithocysts are only present abaxially. Because of these differences we hereby describe it as a new species, named in honour of Cornelis (Cees) Berg: Ficus cornelisiana.

Summary of information related to the detection of a phylogenetic signal (both host insects and plants). (DOCX 20 kb)

Summary of Mantel tests used for the comparative analysis dealing with host plants. (DOCX 19 kb)

Summary of Mantel tests used for the comparative analysis dealing with host insects. (DOCX 21 kb)

Primer sequences used in the study and related references. Table S2. Information (including identification codes, taxonomic identity and Genbank accession numbers) related the specimens used in the phylogenetic analyses. (DOCX 50 kb)

This study uses DNA sequence and morphometric comparisons to investigate the systematic status of a broad-nosed weevil, Cathormiocerus brittanicus (Curculionidae; Entiminae), currently described as an endangered UK endemic. The nuclear marker ITS2 was sequenced from specimens of C. brittanicus, C. myrmecophilus, C. curvipes and C. maritimus. Little sequence differentiation was detected between C. brittanicus and C. myrmecophilus, although both species' sequences were different to those of the other two congeners under study. Multivariate analyses of eight morphometric characters also failed to distinguish C. brittanicus from C. myrmecophilus. The taxonomic status of the two species is therefore questionable. If they are the same species the endangered status of C. brittanicus shall need re-assessing and, because C. myrmecophilus also occurs in France, so will its status as a UK endemic.

High specificity in the Ficus-agaonid wasp mutualism has lead to the assumption of a mostly 'one-to-one' relationship, albeit with some exceptions. This view has been challenged by new molecular data in recent years, but surprisingly little is known about local and spatial genetic structuring of agaonid wasp populations. Using microsatellite markers, we analysed genetic structuring of Ceratosolen fusciceps, the fig wasp pollinating Ficus racemosa, a fig tree species widely distributed from India to Australia. In sampling stretching from the south of China to the south of Thailand we found evidence for only a single pollinating wasp species in continental South-East Asian mainland. We found no evidence for the co-occurrence of cryptic species within our subcontinent sampling zone. We observed no spatial genetic structure within sites and only limited structuring over the whole sampling zone, suggesting that F. racemosa is pollinated by a single population of a single agaonid wasp species all over continental South-East Asia. An additional sample of wasps collected on F. racemosa in Australia showed clear-cut genetic differentiation from the Asian continent, suggesting allopatric divergence into subspecies or species. We propose that the frequent local co-occurrence of sister species found in the literature mainly stems from contact zones between biogeographic regions, and that a single pollinator species over wide areas might be the more common situation everywhere else.

Population differentiation is a crucial step in the speciation process and is therefore a central subject in studies of microevolution. Assessing divergence and inferring its dynamics in space and time generally require a wide array of markers. Until now however, most studies of population structure are based on molecular markers and those concerning morphological traits are more scarce. In the present work, we studied morphological differentiation among populations of the ground beetle Carabus solieri, and tested its congruence with genetic population structure. The shape of pronotum and aedeagus was assessed using Dual Axis Fourier Shape Analysis. manova on Fourier coefficients revealed highly significant morphological variation between populations and a similar geographical pattern of differentiation for both structures. On the whole, morphological and genetic patterns were also found to be congruent. Our analysis confirms the phylogeographical scenario proposing that two entities of C. solieri differentiated during the last glaciation events before recolonizing the actual range of the species. It also indicates a large introgression between the two differentiated entities in the centre of the range.

We investigated the taxonomic significance of nest shape and its putative role in speciation in Trigona (Heterotrigona) carbonaria and T. (H.) hockingsi, two sibling species of stingless bee species from eastern Australia. These species are primarily distinguished by their nest architecture, as in all other respects they are nearly identical. We genotyped 130 colonies from six locations in Queensland at 13 microsatellite loci together with 106 additional colonies from six other Indo-Pacific Trigona species. Whether they were present in allopatry or in sympatry, colonies that displayed the T. carbonaria or the T. hockingsi nest architecture could be unambiguously differentiated at the genetic level. However, T. hockingsi colonies were classifiable into two highly differentiated paraphyletic and geographically separate populations, one in northern and one in southern Queensland. These two populations probably belong to two distinct species, T. hockingsi and T. davenporti nov. sp. Our results suggest that nest architecture characters are relevant but not sufficient criteria to identify species in this group. Consequently, modifications of nest architecture are probably not of prime importance in the speciation process of Australian stingless bees, although nest architecture differences probably result from relatively simple mechanisms. The rare interspecific hybrid colonies detected did not display a nest with an intermediate form between T. hockingsi and T. carbonaria.

Habitat specialist species are supposed to be more susceptible to variations in local environmental characteristics than generalists. To test this hypothesis, we conducted a comparative analysis on abundance and genetic diversity of forest carabids differing in their habitat requirements. Four species were sampled in forests characterized by abiotic, landscape and biotic environmental variables. A statistical framework based on canonical correspondence analysis was used for one habitat generalist and one habitat specialist species to determine the relative contribution of environmental variables in structuring inter- and intrapopulational genetic diversity depicted by microsatellites. Our results showed that sympatric species differed in their sensitivity to environmental variables. The same variables were found to be important in analyses of abundance and genetic data. However, specialization was not related to a greater sensitivity to local environmental characteristics. The strong impact of spatial variables on genetic data suggested that genetic variation among populations would largely reflect the response of individual species to dispersal opportunities more than the effect of habitat quality.

Analysis of genetic isolation by distance (IBD) is of prime importance for the study of processes responsible for spatial population genetic structure and is thus frequently used in case studies. However, the identification of a significant IBD pattern does not necessarily imply the absence of sharp discontinuities in gene frequencies. Therefore, identifying barriers to gene flow and/or secondary contact between differentiated entities remains a major challenge in population biology. Geographical genetic structure of 41 populations (1080 individuals) of an alpine insect species, Carabus solieri, was studied using 10 microsatellite loci. All populations were significantly differentiated and spatially structured according to IBD over the entire range. However, clustering analyses clearly identified three main clusters of populations, which correspond to geographical entities. Whereas IBD also occurs within each cluster, population structure was different according to which group of populations was considered. The southernmost cluster corresponds to the most fragmented part of the range. Consistently, it was characterized by relatively high levels of differentiation associated with low genetic diversity, and the slope of the regression of genetic differentiation against geographical distances was threefold those of the two other clusters. Comparisons of within-cluster and between-cluster IBD patterns revealed barriers to gene flow. A comparison of the two approaches, IBD and clustering analyses, provided us with valuable information with which to infer the phylogeography of the species, and in particular to propose postglacial colonization routes from two potential refugia located in Italy and in southeastern France. Our study highlights strongly the possible confounding contribution of barriers to gene flow to IBD pattern and emphasizes the utility of the model-based clustering analysis to identify such barriers.