Summary1. The effects of the present biodiversity crisis have been largely focused on the loss of species. However, a missed component of biodiversity loss that often accompanies or even precedes species disappearance is the extinction of ecological interactions. 2. Here, we propose a novel model that (i) relates the diversity of both species and interactions along a gradient of environmental deterioration and (ii) explores how the rate of loss of ecological functions, and consequently of ecosystem services, can be accelerated or restrained depending on how the rate of species loss covaries with the rate of interactions loss. 3. We find that the loss of species and interactions are decoupled, such that ecological interactions are often lost at a higher rate. This implies that the loss of ecological interactions may occur well before species disappearance, affecting species functionality and ecosystems services at a faster rate than species extinctions. We provide a number of empirical case studies illustrating these points. 4. Our approach emphasizes the importance of focusing on species interactions as the major biodiversity component from which the 'health' of ecosystems depends.

Phylogeographical inferences, applied in a comparative framework across multiple species at a regional scale, provide the means for detecting regional and landscape-level patterns of biodiversity, which are important for understanding macroecology and evolution in a geographical mosaic against a backdrop broadly impacted by geological events. Although information on Patagonian phylogeographical patterns has accumulated for both aquatic and terrestrial organisms in recent years, no attempt has been made to compare patterns across major organismal groups. In this review, we compiled studies on the phylogeography of co-distributed plants and terrestrial vertebrates from Patagonia. From each study, we extracted information on levels of genetic diversity, and inferred demographic processes and phylogeographical breaks, as well as on putative refugia, to produce the first summary of emerging phylogeographical patterns for this region. This review reveals some congruent phylogeographical patterns within and among plants and terrestrial vertebrates, and suggests that PreQuaternary as well as Quaternary geological events would have been important driving forces in the evolutionary history of Patagonian lineages. Different processes and directional range shifts suggest a mosaic of phylogeographical patterns, far more complex than the several north-south common patterns traditionally proposed.Las inferencias filogeográficas, dentro de un marco comparativo cuando incluyen varias especies a escala regional, permiten detectar patrones de biodiversidad regional y de paisaje (fisonómicos), importantes para entender tanto la macroecología como el impacto a gran escala de los eventos geológicos. En los últimos años, el conocimiento filogeográfico de Patagonia se ha acumulado para organismos acuáticos y terrestres, y aunque se han propuesto pocos patrones demográficos o espaciales cualitativamente concordantes, no se ha hecho ningún intento de revisar comparativamente algunos de esos patrones considerando grandes grupos de organismos. En esta revisión compilamos el conocimiento publicado sobre la filogeografía de plantas vasculares y vertebrados terrestres de Patagonia con el propósito de comparar niveles de diversidad genética, procesos demográficos, quiebres filogeográ-ficos y localización de posibles refugios, para producir el primer resumen de patrones filogeográficos emergentes

Summary 1. Proboscis length has been proposed as a key dimension of plant pollination niches, but this niche space has not previously been explored at regional and global scales for any pollination system. Hawkmoths are ideal organisms for exploring pollinator niches as they are important pollinators in most of the biodiverse regions of the earth and vary greatly in proboscis length, with some species having the longest proboscides of all insects. 2. Using datasets for nine biogeographical regions spanning the Old and New World, we ask whether it is possible to identify distinct hawkmoth pollination niches based on the frequency distribution of proboscis length, and whether these niches are reflected in the depths of flowers that are pollinated by hawkmoths. We also investigate the levels of specialization in hawkmoth pollination systems at the regional and community level using data from interaction network studies. 3. We found that most regional hawkmoth assemblages have bimodal or multimodal distributions of proboscis length, and that these are matched by similar distributions of floral tube lengths. Hawkmoths, particularly those with longer proboscides, are polyphagous and at the network level show foraging specialization equivalent to or less than that of bees and hummingbirds. In the case of plants, shorter-tubed flowers are usually visited by numerous hawkmoth species, while those that are longer-tubed tend to exclude shorter-proboscid hawkmoths and thus become ecologically specialized on longer-proboscid hawkmoth species. Longer-tubed flowers tend to have greater nectar rewards and this promotes short-term constancy by long-proboscid hawkmoths. 4. Our results show that pollinator proboscis length is a key niche axis for plants and can account for patterns of evolution in functional traits such as floral tube length and nectar volume. We also highlight a paradoxical trend for nectar resource niche breadth to increase according to proboscis length of pollinators, while pollinator niche breadth decreases according to the tube length of flowers.

Aim We perform a phylogeographical study of an endemic Patagonian herbaceous plant to assess whether geographical patterns of genetic variation correspond to in situ Pleistocene survival or to glacial retreat and post-glacial expansion. We also seek to determine the locations of potential glacial refugia and post-glacial colonization routes.Location Southern Andes and Patagonian steppe.Methods We used Calceolaria polyrhiza, a widely distributed Patagonian herbaceous plant that occurs mainly in the understorey of Nothofagus rain forests and in the arid Patagonian steppe, as our model system. The chloroplast intergenic spacer trnH-psbA was sequenced for 590 individuals from 68 populations. Sequence data were analysed using phylogenetic (maximum parsimony, maximum likelihood and Bayesian inference) and population genetic (spatial analyses of molecular variance, mismatch distributions and neutrality tests) methods. Nested clade phylogeographic analyses, and divergence time estimates using a calibrated molecular clock, were also conducted.Results A total of 27 haplotypes identified in the present study clustered into four primary genealogical lineages, revealing three significant latitudinal phylogeographical breaks. The two high Andean lineages probably split first, during the late Miocene, and the Patagonian lineage split around 4 Ma, coincident with the establishment of the Patagonian steppe. Within each haplogroup, major diversification occurred in the Pleistocene. The Patagonian groups show a pattern consistent with a rapid post-glacial expansion and colonization of the Andean flanks, achieved independently by four lineages. The highest haplotype diversity was found along a longitudinal transect that is remarkably congruent with the limit of the ice-sheet extension during the Greatest Patagonian Glaciation. A north-east expansion is evident, which is probably associated with the 'Arid Diagonal' fluctuations.Main conclusions Glacial climate fluctuations had a substantial impact on the diversification, distribution and demography of the study species. A scenario of multiple periglacial Pleistocene refugia and subsequent multiple recolonization routes, from eastern Patagonia to the Andean flanks, may explain the phylogeographical patterns observed. However, current genetic structure also preserves the imprints of older events that probably occurred in the Miocene and Pliocene, providing evidence that multiple processes, operating at different spatial and temporal scales, have moulded biodiversity in Patagonia.

A major challenge in evolutionary ecology is to understand how co-evolutionary processes shape patterns of interactions between species at community level. Pollination of flowers with long corolla tubes by long-tongued hawkmoths has been invoked as a showcase model of co-evolution. Recently, optimal foraging models have predicted that there might be a close association between mouthparts' length and the corolla depth of the visited flowers, thus favouring trait convergence and specialization at community level. Here, we assessed whether hawkmoths more frequently pollinate plants with floral tube lengths similar to their proboscis lengths (morphological match hypothesis) against abundance-based processes (neutral hypothesis) and ecological trait mismatches constraints (forbidden links hypothesis), and how these processes structure hawkmoth-plant mutualistic networks from five communities in four biogeographical regions of South America. We found convergence in morphological traits across the five communities and that the distribution of morphological differences between hawkmoths and plants is consistent with expectations under the morphological match hypothesis in three of the five communities. In the two remaining communities, which are ecotones between two distinct biogeographical areas, interactions are better predicted by the neutral hypothesis. Our findings are consistent with the idea that diffuse co-evolution drives the evolution of extremely long proboscises and flower tubes, and highlight the importance of morphological traits, beyond the forbidden links hypothesis, in structuring interactions between mutualistic partners, revealing that the role of niche-based processes can be much more complex than previously known.

Summary1. Pollinator-mediated selection on traits associated with mechanical fit and attraction of pollinators were investigated through both sexual functions in Cyclopogon elatus (Sw.) Schlechter (Orchidaceae). 2. Only halictid bees, principally Augochlora nausicaa , were observed as pollinators. The pollinarium becomes attached to the ventral surface of the bee's mouthparts (labrum) when the proboscis, which closely matches the length of floral tube, is projected into the flower to reach nectar. 3. We detected directional selection on nectary depth, with deeper nectaries favoured only through male fitness, because this trait affects pollinaria removal but not deposition. Correlational selection was detected through male function between nectary depth and the number of flowers in an individual's floral display. These traits affect pollination in a multiplicative way: flower number is positively related to the number of bee visits, and nectary depth positively affects the effectiveness of pollinaria removal at each visit. 4. We also detected stabilizing selection on display size. For smaller displays there was a strongly positive association between number of flowers and overall reproductive success, which can be attributed to a simple numerical effect. However, the expected performance of individual flowers is impaired in large displays by pollinator limitation, because bees visiting the display pollinate few flowers per visit and each bee carries, at most, one pollinarium.

Though visitors are often many times stronger than the operative strength of the flowers they pollinate, exceptionally weak bees such as Apis mellifera cannot open the strongest flowers. On the other hand, strong correlations among certain petal morphometric traits (particularly between the keel and wings) give support to the idea that an intrafloral module is associated with the functioning of the mechanism of these legume flowers. In addition, the highly significant correlations found across petals support the view of functional phenotypic integration transcending the ontogenetic organization of flower structure.

Interactions with pollinators are thought to play a significant role in determining whether plant species become invasive, and ecologically generalised species are predicted to be more likely to invade than more specialised species. Using published and unpublished data we assessed the floral biology and pollination ecology of the South American native Nicotiana glauca (Solanaceae) which has become a significant invasive of semi-arid parts of the world. In regions where specialised bird pollinators are available, for example hummingbirds in California and sunbirds in South Africa and Israel, N. glauca interacts with these local pollinators and sets seed by both out-crossing and selfing. In areas where there are no such birds, such as the Canary Islands and Greece, abundant viable seed is set by selfing, facilitated by the shorter stigma-anther distance compared to plants in native populations. Surprisingly, in these areas without pollinating birds, the considerable nectar resources are only rarely exploited by other flower visitors such as bees or butterflies, either legitimately or by nectar robbing. We conclude that Nicotiana glauca is a successful invasive species outside of its native range, despite its functionally specialised hummingbird pollination system, because it has evolved to become more frequently self pollinating in areas where it is introduced. Its invasion success is not predictable from what is known of its interactions with pollinators in its home range.