Ecological and evolutionary studies largely assume that island populations display low levels of neutral genetic variation. However, this notion has only been formally tested in a few cases involving plant taxa, and the confounding effect of selection on genetic diversity (GD) estimates based on putatively neutral markers has typically been overlooked. Here, we generated nuclear microsatellite and plastid DNA sequence data in Periploca laevigata, a plant taxon with an island-mainland distribution area, to (i) investigate whether selection affects GD estimates of populations across contrasting habitats; and (ii) test the long-standing idea that island populations have lower GD than their mainland counterparts. Plastid data showed that colonization of the Canary Islands promoted strong lineage divergence within P. laevigata, which was accompanied by selective sweeps at several nuclear microsatellite loci. Inclusion of loci affected by strong divergent selection produced a significant downward bias in the GD estimates of the mainland lineage, but such underestimates were substantial (>14%) only when more than one loci under selection were included in the computations. When loci affected by selection were removed, we did not find evidence that insular Periploca populations have less GD than their mainland counterparts. The analysis of data obtained from a comprehensive literature survey reinforced this result, as overall comparisons of GD estimates between island and mainland populations were not significant across plant taxa (N = 66), with the only exception of island endemics with narrow distributions. This study suggests that identification and removal of markers potentially affected by selection should be routinely implemented in estimates of GD, particularly if different lineages are compared. Furthermore, it provides compelling evidence that the expectation of low GD cannot be generalized to island plant populations.

Aim: The loss of dispersal on islands hypothesis (LDIH) posits that wind-dispersed plants should exhibit reduced dispersal potential, particularly if island populations are old. In this study, we tested this hypothesis using a detailed phylogeographical framework across different geographical scales. Location: Mainland and island areas of the Atlantic and Mediterranean regions, including Macaronesia (Canary Islands and Cape Verde) and Mediterranean islands in the strait of Sicily. Methods: Forty-five populations of Periploca laevigata, a wind-dispersed shrub, were sampled. Plastid and nuclear microsatellite data were used to reconstruct spatiotemporal patterns of island colonization, and estimates of seed terminal velocity used as a surrogate for dispersal ability under both field and common garden conditions.Results: Our findings did not provide evidence of loss of dispersability in any island lineage. In all of the regions considered, dispersal ability was similar on island and mainland populations, or higher on islands. Contrary to LDIH expectations, lineages inferred as the oldest (western Canaries and Cape Verde) converged towards the most dispersive seed phenotype. This pattern was supported by data obtained under common garden conditions. Within the western Canarian lineage, successful dispersal was shown to be very rare among islands and extensive within islands, but dispersability did not vary significantly from older to more recent sublineages. Considering all the study islands, we found a strong, positive correlation between dispersal ability and estimates of within-island habitat availability. Main conclusions:This study suggests that dispersal ability can be favoured on islands, possibly because traits enhancing wind dispersal are positively selected when habitat availability is high. Our results challenge broad generalizations of the LDIH, but we discuss how overlooking species 0 phylogeographical history may give rise to misleading conclusions. K E Y W O R D S anemochory, dispersal ability, island colonization, Macaronesia, parallel evolution, seed dispersal

International trade in species that are or may be endangered by collection from the wild is regulated under the Convention on International Trade in Endangered Species of wild fauna and flora (CITES) for 176 member States (Parties). Internet commerce is a relatively new route for such trade. In 2007, the CITES Secretariat asked Parties to collect information on internet wildlife trade and report problems and implemented regulations. The reports indicated it was difficult to even approximate the influence of e-commerce on CITES-listed species (CITES Secretariat 2009). We report a case study in which we quantified international transactions over an internet auction site of CITES-listed cacti and cross-checked them with CITES trade data. Our results were both surprising and alarming.Species protected under CITES are included in different CITES appendices according to their level of threat of extinction from international trade. Taxa listed in Appendix I are endangered and wild collection could cause their extinction, and taxa listed in Appendix II either may become endangered if wild collection is not regulated or are similar in appearance to other species listed in Appendix I or II (see www.cites.org for full definitions). The treaty operates through the issue and control of permits that apply to regular and internet trade. Trade in wild specimens is either prohibited (species listed in Appendix I) or regulated by permits (species listed in Appendix II), although some Parties implement stricter regulations. Export permits must also be issued for certified artificially propagated plants. International trade of plants listed in Appendix I is allowed only if they are artificially propagated. Plants listed in Appendix I that are artificially propagated for commercial purposes are included in Appendix II (Article VII, paragraph 4 of the Convention), and the exporting enterprises should be registered in accordance with Resolution of the Conference of the Parties 9.19 (Revised at CoP15). ‡email matthew.smith@microsoft.com Paper submitted July 4, 2012; revised manuscript accepted November 24, 2012. Parties must submit annual reports to the CITES Secretariat listing the number and type of permits and certificates granted, the States with which such trade occurred, and the quantities and types of specimens traded. Some Parties report actual trade, whereas others report the permits issued. Trade data from these reports are stored in the CITES Trade Database (CTD) (http://www.unepwcmc-apps.org/citestrade/). We used this information to assess the implementation of the Convention for international trade in CITES species over the internet. We investigated e-commerce in 2010 for cacti as a case study. All members of the Cactaceae, with the exception of 3 genera (Pereskia, Pereskiopsis, and Quiabentia) are listed in either Appendix I or II. We also restricted our analyses to species listed in Appendix I because an export permit is mandatory to export and import live plants.We monitored buyer-seller interactions on an internet a...

Dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS) are used by saprophilous insects to locate breeding sites (decaying organic matter), and by brood-site deceptive flowers to attract such insects. However, little is known about the relative importance of these two compounds in eliciting electrophysiological and behavioural responses in the insects. Here, we compared the relative attractiveness of DMDS and DMTS to saprophilous flies in field choice experiments and tested whether potential differences in field responses can be explained by differences in electrophysiological antennal responses to these compounds. Field experiments revealed that the attractiveness of a mixture of these compounds is due to DMTS alone. This result was confirmed by electroantennographic recordings in which flies of four tested species of Calliphoridae (Lucilia sericata, L. caesar, Calliphora vicina, Protocalliphora azurea) and one Muscidae (Musca domestica) respond clearly to DMTS, but not to DMDS. In house flies, however, DMTS elicited electrophysiological responses only, not reflected in behavioural assays. Despite the fact that DMTS and DMDS exhibit similar chemical structures, both the electroantennographic and field responses from saprophilous flies to these two compounds strongly differed. Our study suggests that oligosulfide-responsive saprophilous flies rely on DMTS and not DMDS for finding appropriate breeding sites and that DMTS and not DMDS could act as a key mediator for pollinator attraction in brood-site deceptive plants

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