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Competition for nectar is expected to result in feeding niche differentiation. Here, we targeted the sexually size-dimorphic Volcano Sunbird (Cinnyris preussi) on Mount Cameroon. We investigated whether males and females feed on different plant species, whether females with shorter bills than males prefer shorter flowers, and whether larger dominant males visit more energetic flowers that produce higher amounts of nectar sugars. We also asked whether feeding niches were spatially separated along the elevation gradient and whether this separation varied between the two contrasting seasons. We collected data on the frequency of visits to individual plant species and analyzed the male-to-female ratios in the mist-netted dataset. In addition, we estimated production of nectar sugar in individual habitats and seasons. Despite the large dataset collected, encompassing 6476 bird–plant interactions, our findings did not provide evidence of differences in the spectra of the visited plant species. In addition, females did not visit flowers with shorter tubes, nor did males visit flowers that produced higher amounts of sugars. However, we observed a sex-specific dispersion of sunbirds during the wet season. During the dry breeding season, both males and females feed mainly in nectar-rich montane and submontane forests. In the wet season, the production of nectar sugar in these habitats decreased dramatically, and females largely disappeared. In contrast, female activity increased in the lowest and highest parts of the altitudinal range. Our findings on elevational movements are important in the current context, in which species face potential threats from habitat destruction and climate change. [ABSTRACT FROM AUTHOR]

Aim: Climate change influences species distribution in space and time, but predicting the overlap in the range of interacting species under different climate scenarios remains a challenge. Here, we explore how climate change influences shifts in species ranges among mutualists. Location: Cape Floristic Region (CFR), South Africa. Taxon: Proteaceae and Passeriformes. Methods: We used machine‐learning algorithms (random forest and boosted‐regression trees) and regression model (generalized additive models) to predict range shifts of 11 bird‐pollinated Proteaceae species, combined occurrence prediction of 71 bird‐pollinated Proteaceae and their two most important, endemic, pollinator bird species. We determined the degree of overlap in geographical ranges of nectar‐feeding birds and Proteaceae under different climate scenarios. Species ranges were projected to the years 2050 and 2070 using representative concentration pathways (RCP) 4.5 and 8.5 and three global climate models. Results: The majority of Proteaceae species in our model are predicted to experience range contractions, which ranged from 1% under 2050 RCP 4.5 CCSM4 to 79% under 2070 RCP 8.5 CNRM‐CM5 climate scenarios, leading to 55% and 62% range loss for Cape sugarbird and orange‐breasted sunbird, respectively, under extreme climate scenarios. Proteaceae species are predicted to experience least overlap with nectar‐feeding birds in the northern and eastern range under future climate scenarios. Main Conclusion: Climate change threatens species occupying the mountain range of the northern limit and other regions of the CFR. Reduced range overlap of mutualists may have significant implications for the reproduction and persistence of Proteaceae. We suggest active monitoring of Proteaceae populations in regions where species are predicted to lose their range, particularly so for threatened species with small ranges. [ABSTRACT FROM AUTHOR]

Differences in interaction specializations between nectarivorous birds and plants across continents serve as common examples of evolutionary trajectory specificity. While New World hummingbird-plant networks have been extensively studied and are considered highly specialized, knowledge on the network specialization of their Old World counterparts, sunbirds (Nectariniidae), remains limited. A few studies from tropical Africa indicate that sunbird-plant networks are rather generalized. Unfortunately, these studies are limited to dry seasons and high elevations at the tree line, environments where niche-based hypotheses also often predict lower resource partitioning. In our study, we explored the specialization of sunbird-plant networks and their spatiotemporal variability on Mt. Cameroon (Cameroon). Using a combination of automatic video recordings and personal observations, we constructed eight comprehensive sunbird-plant networks in four forest types at different elevations in both the dry and wet seasons. As reported in previous studies, the montane forest plants, birds and whole networks were highly generalized. Nevertheless, we observed a much higher specialization in forests at lower elevations. Except at the lowest altitude, the wet season was also characterized by higher specialization. While less specialized flowering trees dominated in the dry season networks, more specialized herbs and shrubs were visited by birds during the wet season. As our findings do not support the generally accepted assumption that Old World bird-plant networks are rather generalized, we need further studies to understand the differences in bird-plant specializations on individual continents. [ABSTRACT FROM AUTHOR]

Orange-tufted sunbirds (Cinnyris osea) feed on the nectar of the tobacco tree (Nicotiana glauca) which contains toxic pyridine alkaloids characterized by high concentrations of anabasine and much lower concentrations of nicotine. We aimed at determining whether the gut microbiota of sunbirds harbors bacterial species that enable the birds to cope with these toxic alkaloids. An in vivo experiment that included 12 birds showed that inducing dysbiosis in sunbirds’ guts by the addition of sulfamethoxazole and trimethoprim, significantly reduced the birds’ ability to degrade anabasine (n = 3) compared to control birds (n = 3) with undisturbed microbiota. Sunbirds whose gut bacterial communities were altered by the antibacterial agents and who were fed with added nicotine, also showed a lower percentage of nicotine degradation (n = 3) in their excreta compared to the sunbirds with undisturbed microbiota (n = 3), though this difference was not significant. In an in vitro experiment, we studied the ability of Lactococcus lactis, Enterobacter hormaechei, Chryseobacterium gleum, Kocuria palustris, and Methylorubrum populi that were isolated from sunbirds’ excreta, to degrade anabasine and nicotine. By using gas chromatography-mass spectrometry (GC-MS) analysis, we successfully demonstrated, for the first time, the ability of these species to degrade the focal secondary metabolites. Our findings demonstrate the role of gut bacteria in detoxifying toxic secondary metabolites found in the N. glauca nectar. The degradation products may supply the birds with nitrogen which is scarce in nectar-rich diets. These findings support another role of bacteria in mediating the interactions between plants and their pollinators.

Orange-tufted sunbirds (Cinnyris osea) feed on the nectar of the tobacco tree (Nicotiana glauca) which contains toxic pyridine alkaloids characterized by high concentrations of anabasine and much lower concentrations of nicotine. We aimed at determining whether the gut microbiota of sunbirds harbors bacterial species that enable the birds to cope with these toxic alkaloids. An in vivo experiment that included 12 birds showed that inducing dysbiosis in sunbirds' guts by the addition of sulfamethoxazole and trimethoprim, significantly reduced the birds' ability to degrade anabasine (n = 3) compared to control birds (n = 3) with undisturbed microbiota. Sunbirds whose gut bacterial communities were altered by the antibacterial agents and who were fed with added nicotine, also showed a lower percentage of nicotine degradation (n = 3) in their excreta compared to the sunbirds with undisturbed microbiota (n = 3), though this difference was not significant. In an in vitro experiment, we studied the ability of Lactococcus lactis , Enterobacter hormaechei , Chryseobacterium gleum , Kocuria palustris , and Methylorubrum populi that were isolated from sunbirds' excreta, to degrade anabasine and nicotine. By using gas chromatography-mass spectrometry (GC-MS) analysis, we successfully demonstrated, for the first time, the ability of these species to degrade the focal secondary metabolites. Our findings demonstrate the role of gut bacteria in detoxifying toxic secondary metabolites found in the N. glauca nectar. The degradation products may supply the birds with nitrogen which is scarce in nectar-rich diets. These findings support another role of bacteria in mediating the interactions between plants and their pollinators. [ABSTRACT FROM AUTHOR]

Supplementary feeding of birds may have considerable ecological and evolutionary effects on bird communities. However, there is a lack of basic information on the prevalence, frequency and quality of supplementary feeders, especially in African urban areas. Here we describe the prevalence, reliability and quality of artificial nectar feeders in suburbs in the Cape Floristic Region, South Africa, where many bird-pollinated plant species occur. Results from 291 questionnaires, completed by garden owners with an interest in birds, reveal that 57% of respondents have feeders in their gardens and 51% refill their feeders multiple times per week. The sugar concentration, total duration of feeding and frequency of feeding did not affect abundances or species richness of nectarivorous birds in gardens. We found a higher incidence of breeding sunbirds and sugarbirds in gardens with feeders than gardens without. Supplementary nectar feeding in this area has the potential to contribute to conserving nectarivorous birds, but investigation into the possible negative effects is needed. [ABSTRACT FROM AUTHOR]

Camellia pubipetala is an endemic and endangered species with small and isolated populations occurring only in karst regions in Guangxi of south China. To understand the reproductive biology of C. pubipetala and its possible influences upon its endangered status, its breeding system and pollination ecology were studied in the Longhushan (LHS) and Longzhao (LZ) populations of this species. The flowering duration of the C. pubipetala populations spanned from late January to early April and anthesis of a single flower usually lasted 5–7 days. This species is homogamous, and the pollen and stigma are viable throughout anthesis. Each bagged flower could secrete 141.5 μL of nectar at a sugar concentration of 25.0% during anthesis. The observed high pollen/ovule ratio, and the results of hand‐pollination experiments indicated that this species obligately outcrosses. Open pollination resulted in a significantly decreased fruit set (6.7%) and seed set (38.9%) compared to supplementary pollination treatment (23.3% and 64.7%, respectively), which is indicative of a pollen limitation in the process of pollination. The primary pollinator of C. pubipetala is the sunbird Aethopyga christinae and its visiting frequency is quite low, whereas the honeybee Apis cerana is only an occasional pollinator in wild populations. Low reproductive rates in C. pubipetala were found to be a consequence of few species of pollinators and their low visiting frequency. Pollen limitation may be a crucial factor that contributes to the endangered nature of this species. Artificial pollination and the release of pollinators are effective ways to increase the fruit and seed yield of this species. [ABSTRACT FROM AUTHOR]

Motion-activated cameras ("camera traps") are useful for recording plant–animal interactions that are difficult to observe using conventional means. We used camera traps to document interactions between animal flower visitors and the orchid Satyrium neglectum subsp. woodii and used mesh exclosures which selectively exclude access of larger animals to flowers to test the importance of bird visits for pollination. Camera footage revealed that the orchid is visited by two sunbird species (amethyst and greater double-collared) which carry pollinaria on the upper mandible of their beaks. Plants which could only be accessed by bees and other small insects had few pollinaria removed and set very few fruits relative to plants which could also be accessed by larger animals such as sunbirds. The sturdy inflorescence stem, and thick fleshy perianth tissue, orange–red colour of the flowers, low scent production and large viscidia, are traits shared with other, distantly related bird-pollinated Satyrium species and can therefore be considered likely to play a functional role in bird pollination. We previously made anecdotal observations of sunbird visits to this orchid species in south-central Africa, and this study conducted in populations in South Africa confirms that sunbird pollination is consistent across the highly disjunct distribution of the taxon. [ABSTRACT FROM AUTHOR]

There are two alternative hypotheses related to body size and competition for restricted food sources. The first one supposes that larger animals are superior competitors because of their increased feeding abilities, whereas the second one assumes superiority of smaller animals because of their lower food requirements. We examined the relationship between two unrelated species of different size, drinking technique, energy requirements and roles in plant pollination system, to reveal the features of their competitive interaction and mechanisms enabling their co-existence while utilising the same nectar source. We observed diurnal feeding behaviour of the main pollinator, the carpenter bee Xylocopa caffra and a nectar thief, the northern double-collared sunbird Cinnyris reichenowi on 19 clumps of Hypoestes aristata (Acanthaceae) in Bamenda Highlands, Cameroon. For comparative purpose, we established a simplistic model of daily energy expenditure and daily energy intake by both visitor species assuming that they spend all available daytime feeding on H. aristata. We revealed the energetic gain-expenditure balance of the studied visitor species in relation to diurnal changes in nectar quality and quantity. In general, smaller energy requirements and related ability to utilise smaller resources made the main pollinator X. caffra competitively superior to the larger nectar thief C. reichenowi. Nevertheless, sunbirds are endowed with several mechanisms to reduce asymmetry in exploitative competition, such as the use of nectar resources in times of the day when rivals are inactive, aggressive attacks on carpenter bees while defending the nectar plants, and higher speed of nectar consumption. [ABSTRACT FROM AUTHOR]

During the breeding season male, but not female, individuals of the purple sunbird possess colourful plumage of chiefly blue and black coloration with a splatter of orange and yellow on the chest. Representative feathers of these colours were collected from male birds during the breeding season and analyzed by reflectance and scanning electron microscopy. The rachis, which is the central support of a feather on which various barbs and barbules are arranged, is spongy and made up of keratin layers with rod-shaped melanosomes sparsely distributed within these layers. Barbs and barbules are the structural units of the feather and depending on how they are arranged provide a characteristic shape to the feather. X-Ray diffraction (XRD) analyses of the feathers revealed the presence of various metal elements that might contribute to the feathers’ colorations. Blue feathers are iridescent and contain mainly iron, copper, zinc and cobalt (in that order of abundance); black feathers were also found to contain mainly iron and copper, but chromium instead of zinc and cobalt, while yellow feathers were found to contain predominantly cobalt and nickel. The metal content of the feathers in an as yet unknown way may be involved in the production of the distinct absorbance and reflectance patterns that the brilliant plumage of the purple sunbird is renowned for. [ABSTRACT FROM AUTHOR]

Carnivorous pitcher plants capture insect prey to acquire essential nutrients while growing on extremely poor soils. A few individual species have evolved mutualistic relationships with small mammals that visit the traps to harvest nectar, and in return leave faecal droppings in the pitchers. Here we report that a diverse guild of nectar-harvesting vertebrates visits pitchers of two common lowlandNepenthesspecies without providing any obvious benefit for the plants. Over four consecutive field seasons, we observed four species of sunbirds and one species of tree shrew drinking nectar from pitcher plants. Foraging activity was highest in the morning and late afternoon. Van Hasselt’s, Brown-throated and olive-backed sunbirds were regular and highly abundant pitcher visitors in two different field sites. A crimson sunbird and a lesser tree shrew were each observed harvesting nectar on one occasion. The vertebrates harvested nectar from the pitcher rim (peristome) ofN. rafflesianaand from the underside of the pitcher lid ofN. gracilis. A comparison of the nectar production of these and three further sympatric species revealed exceptionally high quantities of nectar forN. rafflesiana. Other factors such as plant and pitcher abundance and the habitat preferences of the observed vertebrates are likely to also play a role in their choice to visit particular species. This is the first account of a case of obvious nectar robbing fromNepenthespitchers by a guild of species that are too large to serve as prey, while the pitcher size and shape prevent faecal droppings from reaching the pitcher’s inside. This interaction provides an example of a possible starting point for the evolution of the elaborate mutualistic relationships observed in some species. Follow-up adaptations of pitcher shape could enable the plants to catch the droppings of their visitors and turn an exploitative relationship into a mutualism. [ABSTRACT FROM AUTHOR]

Nicotiana species (Solanaceae) are widely distributed, mainly in the Americas and Australia. Nicotiana africana is the only species indigenous to Africa; its populations are confined to isolated mountains in the Namib Desert and thus little is known about this species' reproductive strategy or reliance on pollinators, if any. Plants grow in a sheltered environment among granite boulders and wind pollination is therefore unlikely. Our aim was to use a controlled hand-pollination experiment to identify the pollination requirements of N. africana and thereby infer the level of reliance on pollinators. One of five treatments was applied to flowers: either self- or cross-pollination, with half the flowers being emasculated and half not, and the fifth treatment consisted of unmanipulated flowers. Fruit set, seed set and seed weight were measured to determine pollinator reliance. Fruit set and seed set were similar for crossed and selfed flowers. Our findings show that N. africana is self-compatible but also partially dependant on pollinators for reproduction. Using floral traits, the plant's natural distribution and comparisons with other Nicotiana species, we predict that sunbirds (Nectariniidae) are the most likely pollinators of this species in its natural habitat. [ABSTRACT FROM AUTHOR]

We describe the nest of the endemic Whitehead's Spiderhunter ( Arachnothera juliae) from Mt. Mulu National Park, Sarawak, Malaysian Borneo, and compare it to those of the most closely related species, the Yellow-eared Spiderhunter ( A. chrysogenys) and the Naked-faced Spiderhunter ( A. clarae). The nest was found on 3 August 2014 in lower montane forest at 1,400 m elevation along the summit trail on the western slopes of Mt. Mulu. It consisted of a bowl lined with fine bark material inside a naturally occurring hanging ball of moss 19 m above the ground in a large tree. It contained no eggs, but the pair was observed carrying in nest materials on several occasions. [ABSTRACT FROM AUTHOR]

Cytinus (Cytinaceae) is an enigmatic lineage of parasitic plants distributed in the Mediterranean, Africa and Madagascar, and exhibits variation in floral traits suggestive of multiple pollinator shifts. The flowers of Cytinus sanguineus , a dioecious South African species, are sturdy, bright scarlet, and scentless - a combination of floral characteristics that suggests pollination by nectarivorous birds. However, the emergence of flowers at soil level underneath host shrubs and the absence of perches are not typical features of plants pollinated by sunbirds, which are generally averse to foraging on the ground. We studied the pollination system of C. sanguineus using camera traps, analysis of floral nectar and scent, and spectrophotometry of floral surfaces. We observed that C. sanguineus is pollinated by sunbirds, which readily forage on the ground and transfer pollen on their beaks while drinking copious, diluted nectar from narrowly tubular floral nectaries. High fruit set regardless of spatial separation of male and female flowers indicates efficient pollination. Rodents and insects rarely visit C. sanguineus flowers, likely due to the absence of attractive floral volatiles, and the inaccessibility of nectar for rodents. The pollination system of C. sanguineus is clearly distinguished from those of the rodent-pollinated Cytinus visseri and the ant-pollinated Cytinus hypocistis , where pollinator attraction is achieved through production of specific floral volatiles. Our documentation of bird pollination in Cytinus contributes to understanding of the diversity of pollination systems in this genus. [ABSTRACT FROM AUTHOR]

The bird pollination syndrome is characterized by red, unscented flowers with dilute nectar in long nectar tubes. However, the extent to which plants with such traits actually depend on birds for seed production is seldom determined experimentally, and traits such as colour and scent production are often assessed only subjectively. We documented bird pollination and quantified floral traits in the critically endangered Satyrium rhodanthum ( Orchidaceae) from mistbelt grasslands in the summer-rainfall region of South Africa. Direct observations and motion trigger camera footage revealed amethyst sunbirds as the only pollinators, despite the presence of other potential pollinators. Experimental exclusion of sunbirds significantly reduced pollination and fruit set to near zero. Pollination success in naturally pollinated plants was close to 100% in one year, and fruit set varied from 23 to 64% in other years. Pollen transfer efficiency was 5.8%, which is lower than in related insect-pollinated species, probably due to a tendency of birds to wipe pollinaria from their beak. Flowers of S. rhodanthum only reflect light in the red range of the spectrum, and they produce only a few aliphatic and monoterpene scent compounds at comparatively low emission rates. Nectar volume and sugar concentration varied between 2.7 and 3.7 μL and 23.7 and 25.9%, respectively. We conclude that S. rhodanthum is highly specialized for pollination by sunbirds. Colour, scent and nectar characteristics differ from insect-pollinated Satyrium species and are consistent with those expected for bird-pollinated flowers, and may contribute to lack of visitation by other potential long-tongued pollinators. Habitat loss probably underlies the critically endangered conservation status of S. rhodanthum, but the specialization for pollination by a single bird species means that reproduction in this orchid is vulnerable to losses in surrounding communities of plants that subsidize the energetic requirements of sunbirds. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 177, 141-150. [ABSTRACT FROM AUTHOR]

The abundance of consumers and the availability of resources are often linked, and birds are known to track food resources at a variety of spatial and temporal scales. This study describes the seasonal influx of nectar-feeding birds during flowering in a 51-ha stand of Aloe ferox in the Eastern Cape, South Africa, over 5 years (2008-09 and 2011-13). Bimonthly point counts of birds were conducted before (April-May), during (June-July) and after (August) flowering, which occurs during the austral winter. The abundance of nectar-feeding birds increased significantly during flowering each year, whereas monthly abundances of non-nectarivores were unrelated to flowering. Models fitted to bird count-data revealed a significant interaction between feeding guild (nectarivorous versus non-nectarivorous species) and the percentage of flowering A. ferox over the 5 years of the study, confirming that these guilds responded differently to flowering events. Malachite Sunbirds (Nectarina famosa), which are specialist nectarivores, responded consistently to flowering of A. ferox each year, despite the low sugar concentrations of A. ferox nectar. The arrival of nectar-feeding birds en masse during flowering, and the number of bird species (16) observed feeding on A. ferox nectar, suggest that this plant is an important source of nutrition for birds at a time when other food resources are likely to be scarce. [ABSTRACT FROM AUTHOR]

Highlights: [•] We first show data on group display and off-territory forays in sunbirds. [•] Our results do not support reproductive function of group display, because of its timing and low observed EPCs. [•] Group display is rather used for joint territory (nectar resources) defense. [ABSTRACT FROM AUTHOR]

Factors underlying the Allee effect are still heavily debated in ecology. For plants that rely on pollinators for seed production, decreases in conspecific aggregation may reduce attractiveness to floral visitors and lead to an Allee effect. However, floral visitors often differ in their pollination effectiveness; hence, the likelihood of an Allee effect in plant fecundity may depend on how various flower visitors respond to plant aggregation., We tested for Allee effects on fecundity of individuals across two years in the self-incompatible perennial, Kniphofia linearifolia Baker ( Xanthorrhoeaceae), which has two distinct types of pollinator, birds and native bees., For this, we used three measures of aggregation; population size, density and isolation. We made replicated pollinator observations in populations of various aggregations and quantified fecundity in these populations. To determine the differences in pollinator effectiveness and assess their contribution to fecundity, we selectively excluded bird visitors from K. linearifolia in these populations., We found that population size, but not density or isolation distance, was associated with increased bird abundance and seed set in one of the two years of the study. Bird visitation rate increased with increased plant aggregation within populations. Fruit set and seed set per flower were positively related to bird visitation rate. The difference in seed set per flower between bird-excluded and unmanipulated plants increased with increasing population size. Although birds were much less frequent visitors than bees (on average 2.1 visits plant−1 h−1 compared to 57.5 visits plant-1 h−1), selective exclusion experiments indicated that birds are consistently the more effective pollinators of this species, and therefore most likely to influence fecundity., Synthesis. In this system, characterised by an Allee effect on plant fecundity, birds were the most effective pollinators, responded positively to plant aggregation and were associated with increased fecundity. Therefore, the responses of effective pollinators to plant aggregation may be a factor that underlies Allee effects on plant fecundity. [ABSTRACT FROM AUTHOR]

* Premise of the study: Hermaphroditism in plants can lead to gender conflicts, such as pollen discounting--the loss of siring opportunities following self-pollination, and ovule discounting--the loss of seed production opportunities when self-pollen tubes disable ovules through early inbreeding depression or late-acting self-incompatibility. If ovules are discounted by self-pollination, it can be predicted that emasculation (removal of self-pollen) should increase seed production, as long as pollinators are not deterred by emasculation. * Methods: Using the hermaphroditic Kniphofia linearifolia, which belongs to a lineage known to possess late-acting self-incompatibility, we performed hand-pollinations with either self- or cross-pollen and recorded pollen tube growth and seed production. We paired experimentally emasculated plants with non-emasculated controls and quantified pollinator visitation rates, fruit, and seed set in both groups. * Key Results: Ovules penetrated by tubes from self-pollen uniformly failed to develop into seeds, as expected from ovarian self-incompatibility (or strong early inbreeding depression). Experimental emasculation had no effect on the rate of visitation by birds, the primary pollinators of this species, but led to increased rejection by bees, which are secondary pollinators. Despite reducing visitation by some pollinators, emasculation led to increased seed production and reduced rates of seed abortion. * Conclusions: These results show that female performance in hermaphroditic flowers can be enhanced when flowers are emasculated, even if the overall number of pollinator visits is decreased. The most likely explanation for this effect of emasculation is that it reduces ovule discounting arising from pollinator-mediated self-pollination. [ABSTRACT FROM AUTHOR]

Community-level studies have shown that plant-pollinator interactions are much more generalized than previously expected. Consequently, many authors have questioned the significance of phenotypic complementarity between plants and pollinators and abundance effects in pollination interactions. Here, we compare the behaviour of three sunbird species feeding on the nectar of five plant species in afromontane vegetation. We studied the feeding behaviour with and without consideration of plant abundance (i.e. diet selectivity and diet composition, respectively). The aims of the study were to estimate: (1) how relative resource abundance influences flower selectivity; (2) the degree of phenotypic matching; and (3) whether different plant resource assessment methods give different answers to this question. The results showed that, although sunbirds frequently feed on both morphologically adapted and nonadapted plants, food selectivity data are consistent with the hypothesis of phenotypic complementarity. Moreover, we found that the type of plant abundance measurement can change conclusions in some cases, as individual plants differ in their growth habits and nectar production. This effect was most obvious for the assessment of selectivity of the northern double-collared sunbird ( Cinnyris reichenowi) and for Hypoestes aristata, a plant producing inflorescences composed of a large number of small flowers possessing small amounts of nectar per flower (a high abundance of flowers, but a low abundance of nectar relative to the remaining plant community). © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ••, ••-••. [ABSTRACT FROM AUTHOR]

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 outcrossing 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. [ABSTRACT FROM AUTHOR]

* Premise of the study: The showiness of floral displays is usually explained as an adaptation to attract pollinators. However, selection for less attractive displays imposed by non-pollinating agents, particularly herbivores, may balance pollinator-driven selection for highly visible inflorescences. We investigated whether inflorescence architecture, particularly the unusual groundlevel flowering associated with a specialized bird perch in Babiana ringens may have originated, in part, as an adaptive response to mammalian herbivory. * Methods: We measured levels of herbivory by antelope in populations of B. hirsuta , the putative sister species of B. ringens , which possesses the likely ancestral form of inflorescence architecture. To test for position-dependent effects of herbivory on flowers, we compared the herbivory rates and seed production of manipulated inflorescences in a field experiment. We predicted that flowers at the base of inflorescences would suffer less herbivory than those in apical positions. * Results: We found herbivore damage to flowers in 50% of naturally occurring B. hirsuta plants. Manipulated inflorescences with only basal flowers, and consequently similar infl orescence architecture to B. ringens , experienced significantly lower herbivory and higher seed set than inflorescences manipulated to have only apical flowers. * Conclusions: Our results are consistent with the hypothesis that position-dependent herbivory on inflorescences could have played a role in the evolution of inflorescence design. More specifically, position-dependent herbivory may have selected for the loss of apical flowers. Position-dependent herbivory may have contributed toward the evolution of a naked inflorescence axis, a structure that characterizes B. ringens and functions as a bird perch facilitating cross-pollination by sunbirds. [ABSTRACT FROM AUTHOR]

Nectar-feeding birds are important pollinators in fire-prone regions of the world, but the impact of fires on these bird communities has seldom been studied. Nectar-feeding bird communities were censused during peak flowering, before and after fire in the Cape fynbos of South Africa. The abundance and species richness of nectar-feeding birds decreased at all sites. In a controlled experiment, two common bird-pollinated plants, which flower profusely after a fire, were presented in floral arrays in burnt and unburnt vegetation. Birds visited flowers only in the unburnt areas. The results are surprising given the large number of bird-pollinated plants that have fire-stimulated flowering. [ABSTRACT FROM AUTHOR]

A total of 170 wild birds from Senegal, belonging to 48 species and 9 orders, were searched for lice in 2005 and 2007. Chewing lice were found on 58 birds of 18 species and 5 orders (Columbiformes, Cuculiformes, Coraciiformes, Galliformes and Passeriformes). Twenty-two species of chewing lice of 13 genera were determined. Other nine samples of chewing lice that represent a new host-parasite association were determined at generic level only, because only one sex or nymph of these lice were found. Our records represent the first louse records from passerines Camaroptera brachyura (Cisticolidae), Chalcomitra senegalensis (Nectariniidae), Corvinella corvina (Laniidae), Laniarius barbarus (Malaconotidae), Prinia erythroptera (Cisticolidae) and Turdus pelios (Turdidae). Descriptions and illustrations are given for Brueelia chalcomitrae Najer et Sychra sp. nov. ex Chalcomitra senegalensis (Nectariniidae), Brueelia priniae Najer et Sychra sp. nov. ex Prinia subflava (Cisticolidae), and Philopteroides terpsiphoni Najer et Sychra sp. nov. ex Terpsiphone viridis (Monarchidae). [ABSTRACT FROM AUTHOR]

Abstract: Adaptations of the nectar traits in bird-pollinated flowers are amongst the most discussed aspects of floral evolution. In the case of sunbird-pollinated plants, data on nectar traits originate almost exclusively from the South African region and are very scarce for tropical Africa, where paradoxically the highest sunbird diversity occurs. Here we present a study on the nectar properties of a sunbird-pollinated plant, Impatiens sakeriana, growing in the West African mountains, including the nectar production, diurnal changes in the nectar standing crop, the nectar concentrations, the nectar volumes, total sugar amounts and sugar composition. Moreover we compare the nectar traits of I. sakeriana with six other co-flowering insect-visited plant species. Our results showed that many nectar properties, including high volume (approx. 38μL in flowers unvisited by sunbirds), low sugar concentration (approx. 30% w/w) and high sucrose content (95%), are specific to I. sakeriana, compared to the insect-visited plants. These are in accordance with the most recent theory that nectar properties of the sunbird-pollinated plants are similar to those pollinated by hummingbirds. [Copyright &y& Elsevier]

A new mite, Lasioseius senegalensis n. sp. (Acari, Gamasina, Blattisociidae), is described. Lasioseius senegalensis n. sp. was found in Senegal on flowers of mistletoe Englerina lecardii (Engl.) Balle and on beaks of Scarlet-chested sunbirds Chalcomitra senegalensis (L. 1766) searching for food in the flowers of E. lecardii. L. senegalensis n. sp. differs from similar species by short smooth setae Z4, longer ventri-anal shield, number of ventrianal setae and absence of setae J1. A re-examination of the type material of Lasioseius cinnyris Fain and Mariaux, 1991 also was done and figures of the legs are newly presented. [ABSTRACT FROM AUTHOR]

The winter-flowering succulent Aloe marlothii provides nectar for many opportunistic avian nectarivores in southern African savannas. We assessed the importance of A. marlothii nectar sugar for opportunistic nectarivores by analysing temporal changes in stable carbon isotope ratios (δC) in the tissues of birds in Suikerbosrand Nature Reserve, South Africa. The blood of the 11 most common non-granivorous opportunistic nectarivores at our site was enriched in C by 3.4 ± 1.5‰ during the flowering period of A. marlothii, reflecting the enriched crassulacean acid metabolism (CAM) isotopic signature of nectar (−12.6 ± 0.5‰). This relatively small contribution of A. marlothii nectar to assimilated carbon in whole blood contrasted with that of exhaled CO in African Red-eyed Bulbuls Pycnonotus nigricans and Cape White-eyes Zosterops capensis. In both these species, the δC of breath samples was significantly enriched compared with blood and feathers, and closely resembled that of the nectar, revealing combustion of ingested nectar rather than assimilation. Although our analysis was complicated by the presence of C grasses, whose δC values are similar to those of CAM photosynthesizers, when considered with previously published feeding observations our data reveal that opportunistic nectarivores feeding on A. marlothii nectar obtain a relatively small fraction of their assimilated carbon, but most of their metabolized carbon, from this seasonally available carbohydrate food resource. Because the δC values of insects associated with C plants also became enriched during the flowering season, some insect-eating opportunistic nectarivores may have assimilated A. marlothii carbon indirectly from insects. This study highlights the importance of understanding isotopic routing when assessing the nutritional significance of specific dietary items to consumer communities. [ABSTRACT FROM AUTHOR]

Plasma glucose concentrations in birds are much higher than those in mammals of similar body mass, and they are thought to be kept more or less constant. We investigated plasma glucose concentrations of Malachite Sunbirds ( Nectarinia famosa) to determine whether there was a circadian rhythm in plasma glucose and whether plasma glucose concentrations rose at lower temperatures. We explored the possibility that glycogenolysis and gluconeogenesis might be used by birds before daylight to generate body heat during arousal from torpor or from overnight adaptive heterothermy. Plasma glucose concentration of Malachite Sunbirds were relatively high, between 13.6 and 21.4 mmol/L. Plasma glucose concentrations were higher at 5°C than at 25°C, and generally lower during the scotophase, particularly in the early hours of the morning. Therefore, it appears that Malachite Sunbirds are not increasing plasma glucose concentrations during arousal from torpor or to increase scotophase body temperature levels to photophase levels. It is apparent that these nectarivorous birds have a circadian variation in plasma glucose concentrations that is affected by ambient temperature and feeding patterns. [ABSTRACT FROM AUTHOR]