Sugar and protein digestion in flowerpiercers and hummingbirds: a comparative test of adaptive convergence

Flowerpiercers are the most specialized nectar-feeding passerines in the Neotropics. They are nectar robbers that feed on the sucrose-rich diet of hummingbirds. To test the hypothesis that flowerpiercers have converged with hummingbirds in digestive traits, we compared the activity of intestinal enzymes and the gut nominal area of cinnamon-bellied flowerpiercers (Diglossa baritula) with those of eleven hummingbird species. We measured sucrase, maltase, and aminopeptidase-N activities. To provide a comparative context, we also compared flowerpiercers and hummingbirds with 29 species of passerines. We analyzed enzyme activity using both standard allometric analyses and phylogenetically independent contrasts. Both approaches revealed the same patterns. With the exception of sucrase activity, hummingbirds digestive traits were indistinguishable from those of passerines. Sucrase activity was ten times higher in hummingbirds than in passerines. Hummingbirds and passerines also differed in the relationship between intestinal maltase and sucrase activities. Maltase activity was two times higher per unit of sucrase activity in passerines than in hummingbirds. The sucrase activity of D. baritula was much lower than that of hummingbirds, and not unlike that expected for a passerine of its body mass. With the exception of aminopeptidase-N activity, the digestive traits of D. baritula were not different from those of other passerines.Abbreviations K_m Michaelis-Menten constant - PDAP phenotypic diversity analysis program - PIC phylogenetic independent contrast - V_max maximal reaction velocityCommunicated by G. Heldmaier     

Oriole pollination ofErythrina breviflora (Leguminosae): Evidence for a polytypic view of ornithophily

Erythrina breviflora is visited by large numbers of passerine birds of which orioles (Icterus: Icteridae) are the primary pollinators. The flowers produce large quantities of nectar but they are rarely visited by hummingbirds. Inflorescence and floral morphology, and low levels of sucrose in the nectar probably explain the rarity of foraging hummingbirds. A comparison of Old WorldErythrina and their pollinators with New World species pollinated by orioles and hummingbirds suggests that parallel evolution has occurred. When the comparison is expanded to include other species pollinated by orioles, it is clear that various New WorldIcteridae, Thraupidae, etc. are ecological equivalents of Old WorldOriolidae, Pycnonotidae, Sturnidae, etc. and that flowers pollinated by these birds have similar characteristics.     

Distyly and sequential pollinators of Psychotria nuda (Rubiaceae) in the Atlantic rain forest, Brazil

Reciprocal herkogamy is known to promote intermorph-pollination in distylous species, which are generally self- and intramorph-incompatible. Legitimate crossing rates are also influenced by pollinator foraging strategy, which determines most of the pollen flow in natural populations. This study reports on the floral morphology, compatibility relations and pollination biology of Psychotria nuda (Cham. and Schltdl.) Wawra in the Atlantic rain forest, southeastern Brazil, based on floral measurements, hand-pollination experiments and focal observation of floral visitors. It was found that P. nuda does not present an exactly reciprocal herkogamy, however, this morphological trait in P. nuda is as good as in most of Rubiaceae. Reproductive experiments showed compatibility relations similar to those frequently observed in distylous species. The hummingbirds Ramphodon naevius and females of Thalurania glaucopis were the main pollinators of P. nuda, presenting the traplining foraging strategy, which seems to maximize intermorph crosses in P. nuda flowers. These hummingbirds pollinated P. nuda flowers sequentially throughout the flowering period.     

Nectar by day and night:Siphocampylus sulfureus (Lobeliaceae) pollinated by hummingbirds and bats

Most species of the neotropical genusSiphocampylus are believed to be bird-pollinated. The pollination biology ofSiphocampylus sulfureus was studied in a montane region in SE Brazil. This species has features intermediate between ornithophilous and chiropterophilous syndromes: it presents a striking combination of yellowish flowers with strong odour (chiropterophilous features), and diurnal anthesis and sucrose-dominated nectar (ornithophilous features). Major pollinators were hummingbirds by day, and a phyllostomid bat by night.Siphocampylus sulfureus may be viewed as a recent derivate from the presumed ornithophilous stock within sect.Macrosiphon, and thus benefits from the activity of both diurnal and nocturnal vertebrate pollinators.Dedicated to DrIlse Silberbauer-Gottsberger and Prof. DrGerhard Gottsberger for their pioneer contribution to floral biology in Brazil.     

Mycoflora of birds' nests in nest-boxes

A mycoflora has been investigated in 57 nests of 8 free-living birds' species, placed in nest boxes, on 3 localities in Czechoslovakia. The nests have been shown to be densely inhabited by fungi: 476 isolates ofPhycomycetes, Ascomycetes and Fungi Imperfecti have been recorded, the mean number being 8.4 species in a nest. Keratinolytic fungi have been found in 92.8 % of nests, with the most commonly isolated speciesArthroderma ciferrii, Anixiopsis stercoraria, Chrysosporium keratinophilum, C. tropicum, Ctenomyces serratus, Arthroderma tuberculatum, A. quadrifidum andA. curreyi. From present studies results that birds' nests placed in holes or in boxes supposing they are lined with keratinous material could probably be the dominant habitat ofA. ciferrii (stat. con. =Trichophyton georgiae). Cellulolytic fungi have been found in 87.7 % of the nests, most often species of the generaFusarium, Chaetomium, Alternaria, Phoma andCladosporium. Further, fungi potentially zoopathogenic have been isolated (73.7 % of nests and 13.9 % of all isolates), e.g.,Absidia lichtheimii, Aspergillus amstelodami, A. flavus, A. fumigatus, A. nidulans, A. niger, Candida albicans, C. tropicalis, Microsporon cookei andTrichophyton ajelloi. In many cases have also been ascertained fungi causing sooty mildews of various plants (Alternaria alternata, Aureobasidium pullulans, Cladosporium spp.).As factors influencing both qualitative and quantitative composition of the mycoflora in the nests have been established: composition of lining material, its humidity and pH, birds' species, fledging, repeating nesting in a box, and locality.In keratinolytic fungi, the highest competitive saprophytic ability on a given substrate have revealedC. keratinophilum, A. stercoraria, A. ciferrii andC. tropicum, while the lowest oneA. quadrifidum andA. cuniculi.     

New specimens of the early Oligocene Old World hummingbird Eurotrochilus inexpectatus

New specimens of the early Oligocene (32 million years ago) stem group hummingbird Eurotrochilus inexpectatus Mayr, 2004, are described from the type locality Frauenweiler in Southern Germany. One of these is the second slab of the holotype, whose existence has been hitherto unknown. The new fossils add significantly to our knowledge of the morphology of E. inexpectatus and allow more detailed comparisons with other stem and crown group Trochilidae. A new apomorphy of the clade (Eurotrochilus + crown group Trochilidae) is described. With species successively more closely related to the crown group, the temporal sequence of stem group hummingbirds in Europe indicates an Old World origin of Pan-Trochilidae. E. inexpectatus is the earliest long-beaked stem group hummingbird with hovering capabilities, and absence of modern-type hummingbirds before the early Oligocene may provide a maximum age for the origin of hummingbird-pollinated plants and the colonization of the New World by modern-type stem group hummingbirds.     

The first occurrence of the ctenophore <Emphasis Type="Italic">Mnemiopsis leidyi</Emphasis> in the North Sea

After the discovery of large densities of Mnemiopsis leidyi in the Baltic Sea near Kiel by Javidpour et al. (First record of Mnemiopsis leidyi A. Agassiz 1865 in the Baltic Sea, 2006) in October 2006, we investigated the gelatinous zooplankton in the North Sea near Helgoland and recorded Mnemiopsis leidyi for the first time in the North Sea, albeit in much lower densities than those recorded in the Baltic Sea.     

Mobility of Impatiens capensis flowers: effect on pollen deposition and hummingbird foraging

Flexible pedicels are characteristic of birdpollinated plants, yet have received little attention in studies of hummingbird-flower interactions. A major implication of flexible pedicels is that flowers may move during pollination. We examined whether such motion affected interactions between ruby-throated hummingbirds (Archilochus colubris) and jewelweed (Impatiens capensis) by increasing pollen deposition and by altering the effectiveness of nectar removal. For I. capensis, flower mobility enhanced pollen deposition: birds had significantly longer contact with anthers and more pollen deposited on their bills and crowns when foraging at mobile flowers than at flowers that had been experimentally immobilized. In contrast, flower mobility imposed a cost on hummingbirds by significantly increasing their handling times and reducing their extraction rates relative to their interactions with immobile flowers. Field observations indicated that the motion observed during hummingbird visits did not occur when bees (Bombus spp., Apis mellifera) visited I. capensis flowers, which suggests that the mobility of I. capensis flowers is an adaptation for hummingbird pollination.     

Parasites of the spotted stalk borer,Chilo partellus [Lepidoptera: Pyralidae] in South Africa

One egg parasite, 7 larval parasites, 2 pupal parasites and 3 larval hyperparasites were recorded parasitizing the spotted stalk borer,Chilo partellus (Swinhoe) on maize and grain sorghum in South Africa.Trichogrammatoidea lutea Girault [Trichogrammatidae] parasitized eggs ofC. partellus mainly in mid-summer. The larval parasites were active throughout the season with occasional peaks of up to 75% parasitism.Apanteles sesamiae Cameron [Braconidae], proved to be the most abundant larval parasite. It was recorded fromca. 93% of parasitized larvae but its efficiency was reduced by the hyperparasite,Aphanogmus fijiensis (Ferriére) [Ceraphronidae], which reached sometimes up to 100% parasitism on cocoons ofA. sesamiae. The efficiency ofIphiaulax sp. [Braconidae], the 2^nd most abundant larval parasite, was also hindered by the hyperparasite,Eurytoma sp. [Eurytomidae] Pupal parasites were sometimes very abundant reaching up to 100% parasitism without any interference by hyperparasites. The most abundant pupal parasites wereDentichasmias busseolae Heinrich [Ichneumonidae] andPediobius furvus (Gahan) [Eulophidae].      

Effect of floral orifice width and shape on hummingbird-flower interactions

Nectar guides are common among insect-pollinated plants, yet are thought to be rare or absent among hummingbird-pollinated plants. We hypothesize that the lower lips and trumpet-shaped orifices of many hummingbird flowers act as nectar guides to direct hummingbirds to the flowers' nectar and orient the birds for pollination. To test this hypothesis we conducted laboratory experiments using flowers of Monarda didyma (bee balm) and M. fistulosa (wild bergamot), which have orifice widths of about 4 mm and 2 mm, respectively, and latex flowers with orifice widths of 4 mm and 2 mm and three orifice shapes (trumpet, lipped, and lipless). Rubythroated hummingbirds (Archilochus colubris) made fewer errors during bill insertion and spent a smaller proportion of their feeding visit in error at M. didyma flowers than at M. fistulosa flowers, and at unaltered flowers of both species than at flowers with lower lips removed. Handling times were longer at both lipped and lipless flowers of M. didyma than at those of M. fistulosa, and at lipped than at lipless flowers of M. didyma. The average duration of contact between a hummingbird and a flower's anthers and stigma was longer at M. didyma than at M. fistulosa for both lipped and lipless flowers, and at lipped than at lipless M. didyma flowers. Hummingbirds missed the openings of latex flowers with their bills more frequently and spent a greater percentage of their total feeding visit in error at (i) 2-mm than at 4-mm flowers of all three shapes, (ii) lipless flowers than at trumpet or lipped flowers, and (iii) lipped flowers than at trumpet flowers of both widths. The duration of hummingbird/anther contact was longer at (i) 2-mm than at 4-mm flowers of all shapes, (ii) lipped than at trumpet or lipless flowers, and (iii) lipless than at trumpet flowers for both widths. No significant differences in handling times of hummingbirds were observed among any of the latex flower shapes or widths. Our results demonstrate that orifice shapes can act as guides by reducing the frequency of feeding errors by visiting hummingbirds, and that effects of orifice shape on pollination must be considered in conjunction with flower widths and locations of anthers and stigmas.     

The pollination biology of two species of Helicteres (Malvaceae) with different mechanisms of pollen deposition

Species of Helicteres are pollinated mainly by hummingbirds and bats. Most species pollinated by hummingbirds have a mechanism of depositing pollen on the top of the pollinator's head such as is shown in this work for Helicteres sacarolha. H. brevispira has an unusual mechanism of depositing pollen grains under the tail or on the abdomen of the hummingbirds. The top of the birds’ head may be considered an efficient place to transport pollen grains, because it is plain, easily accessible for deposition and donation of pollen and not easily accessible for grooming, while the tail is movable and inclined. Thus, H. brevispira pollinators may carry or transfer fewer amounts of pollen grains than H. sacarolha pollinators from one flower to another. If a large amount of pollen grains is lost, a higher quantity of flower or pollen has to be produced to guarantee reproductive success. Plants of H. brevispira set higher number of flowers and pollen grains per flower than H. sacarolha and have also higher rates of fruit and flower abortion. Thus, pollination efficiency of H. brevispira may be reached by high pollen and flower production. Flower change mechanism presented in this species may be also involved with the optimization of pollinator feeding and pollination efficiency.     

Two interesting cleistothecial Ascomycetes from soils

A new variety ofThermoascus, Thermoascus crustaceus var.verrucosus, is described and illustrated. It is characterized by producing prominently verrucose ascospores. The other characters are almost identical with those of the type variety.Leucothecium coprophilum, a rare ascomycete that has only previously been reported from Spain, is recorded from soils in Taiwan and Korea.     

The systematic relationships ofAegialitis (Plumbaginaceae) as revealed by pollen morphology

Light and first SEM observations on the pollen ofAegialitis indicate that the two species of the genus are clearly distinguishable from all other genera of the tribeStaticeae to whichAegialitis presently is relegated. Intraspecific exine or aperture dimorphism which appears frequently in this tribe, is not recorded in this genus.A. annulata andA. rotundifolia have distinct monomorphic pollen and show a great resemblance in exine features with the tribePlumbagineae, particularly species ofPlumbago. Considering these and other features, separate subtribal status forAegialitis within thePlumbagineae is proposed.     

New species and a new record of Cycas (Cycadaceae) from Thailand

Two newCycas species from Thailand are here described.C. petraea andC. elephantipes. A noteworthy extensions of the range ofC. macrocarpa into southeastern Thailand is recorded. New taxa are illustrated, distributions of the new taxa are mapped, and a key to the species ofCycas in Thailand is provided.     

<Emphasis Type="Italic">Msx</Emphasis> genes are expressed in the carapacial ridge of turtle shell: a study of the European pond turtle,<Emphasis Type="Italic"> Emys orbicularis</Emphasis>

The turtle shell forms by extensive ossification of dermis ventrally and dorsally. The carapacial ridge (CR) controls early dorsal shell formation and is thought to play a similar role in shell growth as the apical ectodermal ridge during limb development. However, the molecular mechanisms underlying carapace development are still unknown. Msx genes are involved in the development of limb mesenchyme and of various skeletal structures. In particular, precocious Msx expression is recorded in skeletal precursors that develop close to the ectoderm, such as vertebral spinous processes or skull. Here, we have studied the embryonic expression of Msx genes in the European pond turtle, Emys orbicularis. The overall Msx expression in head, limb, and trunk is similar to what is observed in other vertebrates. We have focused on the CR area and pre-skeletal shell condensations. The CR expresses Msx genes transiently, in a pattern similar to that of fgf10. In the future carapace domain, the dermis located dorsal to the spinal cord expresses Msx genes, as in other vertebrates, but we did not see expansion of this expression in the dermis located more laterally, on top of the dermomyotomes. In the ventral plastron, although the dermal osseous condensations form in the embryonic Msx-positive somatopleura, we did not observe enhanced Msx expression around these elements. These observations may indicate that common mechanisms participate in limb bud and CR early development, but that pre-differentiation steps differ between shell and other skeletal structures and involve other gene activities than that of Msx genes.Edited by D.A. Weisblat     

Pollination biology ofSymphonia globulifera (Clusiaceae)

The pollination biology ofSymphonia globulifera was studied in Central Amazonia, Brazil. As suggested by the bird syndrome of the flowers, these are mainly pollinated by hummingbirds. Occasional visits by other birds, butterflies and more rarely bees, as well as tamarin monkeys were also observed.Trigona bees partly destroy the flower tube to rob nectar. The possibility thatS. globulifera may not be primarily adapted to hummingbird pollination is discussed. The pollen is intermixed in an oily fluid secreted by the anthers (antheroil). Each of the five stigmas consists of a pore-like opening at the apex and a small chamber behind it. The antheroil mixed with pollen is absorbed by capillarity into the chamber when deposited on the pore. the pollen germinates inside the stigma. The presence of antheroil and pore-like stigmas in the flowers of the closely relatedPlatonia insignis indicate a similar mode of pollination. The results of this study are compared with observations in some otherClusiaceae (Caraipa, Clusia, Garcinia, Mahurea), where floral oils or floral resin occur. The role of these substances in the pollination process and their relation to the evolution of flower biology inClusiaceae are briefly discussed.     

Analysis of esterase zymograms ofFusarium sambucinum and related species

Esterase zymograms were obtained following polyacrylamide slab gel electrophoresis of protein extractsFusarium sambucinum and related species originating from different geographic locations and different matrices. The sites of esterase activity were recorded, and the R_fs were calculated. The data were used for the construction of phenograms by cluster analysis and nonlinear mapping by computerized classification techniques. The fifteen isolates ofF. sambucinum, the eight isolates ofF. torulosum and the six isolates ofF. spec. nov. each had identical profiles, and are therefore electrophoretically distinct species. The isolates ofF. sarcochroum, one ofF. sambucinum sensu lato (BBA 64280) and fifteen isolates ofF. sambucinum were electrophoretically indistinguishable from each other. We assume they are synonymous. The isolate ofF. bactridioides, one ofF. sambucinum sensu lato (BBA 64993) and eight isolates ofF. torulosum had uniform EST patterns, therefore the two species are electrophoretically identical. We assume they are also synonymous. The remaining three isolates ofF. sambucinum sensu lato are somewhat closely related toF. sambucinum isolates on the basis of our investigations.     

Sub-cellular distribution of nitrogen compounds inAzolla andAnabaena by ESI and EELS analysis

Summary The sub-cellular localization of some nitrogen compounds within the leaf cavities ofAzolla filiculoides Lam. was obtained by means of electron spectroscopic imaging (ESI) and electron energy loss spectroscopy (EELS). The analyses were performed on ultrathin unstained sections of differentAzolla leaf cavities which contain epidermal hairs,Anabaena azollae Strasb. and bacteria. Net nitrogen distributions were visualized by image analysis, and nitrogen peaks were evidenced in spectra recorded in the same areas. Different distributions of nitrogen compounds were observed within the leaf cavities along the stem, in particular inside the epidermal hairs ofAzolla and the vegetative cells and heterocysts ofA. azollae.     

First record ofPhytoseiulus persimilis (Acari: Phytoseiidae) in Turkey

The predatory mitePhytoseiulus persimilis Athias-Henriot is widely used for biological control of spider mites in greenhouse. Despite its records from various Mediterranean countries,P. persimilis was not recorded from Turkey. Here we report the natural colonies ofP. persimilis observed along the Mediterranean coast of Turkey.     

aubergine mutations in Drosophila melanogaster impair P cytotype determination by telomeric P elements inserted in heterochromatin

Transposable P elements inserted in the heterochromatic Telomeric Associated Sequences on the X chromosome (1A site) of Drosophila melanogaster have a very strong capacity to elicit the P cytotype, a maternally transmitted condition which represses P element transposition and P-induced hybrid dysgenesis. This repressive capacity has previously been shown to be sensitive to mutant alleles of the gene Su(var)205, which encodes HP1 (Heterochromatin Protein 1), thus suggesting a role for chromatin structure in repression. Since an interaction between heterochromatin formation and RNA interference has been reported in various organisms, we tested the effect of mutant alleles of aubergine, a gene that has been shown to play a role in RNA interference in Drosophila, on the repressive properties of telomeric P elements. Seven out of the eight mutant alleles tested clearly impaired the repressive capacities of the two independent telomeric P insertions at 1A analyzed. P repression by P strains whose repressive capacities are not linked to the presence of P copies at 1A were previously found to be insensitive to Su(var)205; here, we show that they are also insensitive to aubergine mutations. These results strongly suggest that both RNA interference and heterochromatin structure are involved in the establishment of the P cytotype elicited by telomeric P elements, and reinforce the hypothesis that different mechanisms for repression of P elements exist which depend on the chromosomal location of the regulatory copies of P.Communicated by G. Reuter