Small Bees Research Articles

A scientific note on peripheral compound eye morphology of small and normal-sized honey bee drones

Honey bee colonies comprise two sexes, males (drones) and two castes of females. The majority of females are sterile and perform colony maintenance and foraging tasks (the workers), while the sole ...

Wild bee pollinator communities of lowbush blueberry fields: Spatial and temporal trends

Pollination by bees (Apoidea) is a critical component of lowbush blueberry (Vaccinium angustifolium Ation: Ericaceae) production. Though most blueberry growers in eastern Canada use managed bees in lowbush blueberry pollination, native pollinators are recognized as an important component of the pollination service provision. In this study we examined the diversity and abundance of native bees in lowbush blueberry fields in Nova Scotia, while considering spatial and temporal patterns in their distribution over the growing season. In total, we collected 95 species representing 13 genera, of which Lasioglossum and Andrena comprised >92% of all individuals. The abundance of several of the most common species was inversely related to distance from the forest edge, but was low inside the adjacent forest. In contrast, species diversity was highest inside the forest and consistently low within fields. Larger bees were found further into fields than smaller bees. Whereas some abundant bees were collected most often outside the blueberry bloom period, Lasioglossum cressonii, the most abundant species, was collected often during blueberry bloom, suggesting it could be an effective pollinator in this system. The results highlight wild bee taxa that could be targeted for conservation efforts to potentially decrease reliance on managed pollinators.

Taxonomic revision of Parasarus (Hymenoptera: Apidae s.l.: Protandrenini), a South American genus of bees

Parasarus Ruz, 1993 comprises small black bees (3-5 mm long) endemic to xeric regions of South America, mainly along of the Andean Cordillera. Prior to this study, the genus included only the type-species P. atacamensis Ruz, 1993 (from northern Chile) which has mesoscutum strongly reticulated and inner hind tibial spur curved apically. In this paper, a taxonomic revision of Parasarus is presented and two new species are described: P. specularis sp. nov. (from central to northwest Argentina) diagnosed mainly by pygidial plate of female extremely acute apically and labral plate yellow in male; and P. spiniventris sp. nov. (only recorded from central portion of Chile) diagnosed by antennal socket below middle of face, subantennal area as long as broad, metapostnotum smooth, and sternum 3 of male with a tuft of stiff hairs. The morphological variation related to the type-species was studied and not considered sufficiently to recognized distinct species into P. atacamensis. Distribution maps, floral associations, key to species of the genus, and illustrations of general external morphology and genitalia are also provided.

Comparative Anatomy of Reproductive Structures in Cyclanthaceae (Pandanales)

Premise of research. The Neotropical family Cyclanthaceae is one of five families of the order Pandanales, which includes some misfit taxa that are morphologically highly anomalous. In the taxonomically isolated genus Cyclanthus, which is sister to all other Cyclanthaceae, individual flowers are not readily distinguishable. Instead, flowers are replaced by discoidal rings that encircle the inflorescence. We compare features that are shared among misfit taxa.Methodology. We use scanning electron microscopy and light microscopy to describe the reproductive structures of both subfamilies of Cyclanthaceae, including Cyclanthus bipartitus (Cyclanthoideae) and several Carludovicoideae.Pivotal results. Our pollination observations on Carludovica palmata flowers contrast with some other reports, because we observed only small black bees of the Meliponini tribe visiting this species. The anomalous reproductive structures of Cyclanthus show some features in common with Carludovicoideae, especially the presence of l...

Exotics on exotics: Pollen analysis of urban bees visiting Sedum on a green roof

Numerous bee species were collected from a single green roof over the blooming period of the dominant exotic plant type, Sedum, a succulent stonecrop widely used in the green roof industry. As green roofs become more common in cities, an understanding of the potential positive and negative impacts of widespread use of this exotic but useful plant is needed. In this study we sampled bees visiting a green roof in downtown Toronto and compared the proportion of Sedum pollen in the loads they were carrying back to nesting locations. It was found that smaller bees (e.g. Lasioglossum, Hylaeus) were significantly less common on the roof compared with medium (e.g. Apis, Megachile) and large-sized bees (e.g. Bombus, Andrena). The proportion of Sedum pollen in the pollen loads of foraging bees collected was high amongst all bees (average of 80.5 % of total pollen load), but significantly greater for exotic bees compared to native bees. Moreover, native bees had significantly greater numbers of non-Sedum pollen types comprising more than >20 % of their pollen loads, meaning bees could be visiting flowers at ground level and on the roof in the same foraging bout. As the number of green roofs in cities increase, the characteristics of their designs, including the vegetation type and diversity, could have a significant impact in shaping local urban bee communities.

Biological Flora of the British Isles: Epipactis palustris

Summary This account presents information on all aspects of the biology of Epipactis palustris (L.) Crantz that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characteristics, herbivores and disease, history, and conservation. Epipactis palustris is native to Britain, being widely distributed throughout England and Wales, but is less common in the north. Although absent from most of Scotland, it occurs as far north as Perthshire. It is widely distributed in Ireland. The species extends throughout most of Europe, occurring as far east as Mongolia and the north of Turkey, but it is absent from the southern Mediterranean region. Epipactis palustris grows mainly in full sunlight, rarely under shade, and on calcareous, but nutrient‐poor, moist to wet substrates. It favours flushed or seasonally inundated areas in which the intensity of competition from other vegetation is low. It is most commonly found in wet dune slacks, calcareous fens and on peat, but it also occurs on sandy substrates overlying heavy clay or loamy soils. Occasionally, it can also be found near the top of slopes in chalk downland. Epipactis palustris multiplies both by vegetative propagation and sexual reproduction. Vegetative propagation involves the production of regularly branched rhizomes. It flowers in Britain from the end of June until the beginning of September. The flowers produce nectar, which is often colonized by bacteria and to a lesser extent by yeasts. The species is pollinated by a wide range of insects, including honeybees, flies, wasps, beetles, bumblebees and ants, but is also capable of limited spontaneous autogamy. The most efficient pollinators are small bees and solitary wasps. Fruit production is generally high (>80% of the flowers produce capsules). Epipactis palustris is vulnerable to changes in soil water level and to substrate nutrient enrichment. It has suffered a strong decline in its distribution range in Britain, with most losses of local populations occurring before 1930. Habitat destruction and drainage of marshes and fens appear to be the most common causes for the decline of the species. Restoration of old wet dune slacks by topsoil removal and addition of hay from neighbouring vegetation has been successful in encouraging colonization and establishment of populations of the species within a few years. Cessation of draining of mires may also promote the long‐term survival of populations of the species.

Pollinator body size mediates the scale at which land use drives crop pollination services

Summary Ecosystem services to agriculture, such as pollination, rely on natural areas adjacent to farmland to support organisms that provide services. Native insect pollinators depend on natural or semi‐natural land surrounding farms for nesting and alternative foraging resources. Despite interest in conserving pollinators through habitat restoration, the scale at which land use affects pollinators and thus crop pollination services is not well understood. We measured abundance of native, wild bee pollinators and the pollination services they provided to highbush blueberry Vaccinium corymbosum L. crops at 16 sites that varied in the proportion of surrounding agricultural land cover at both the field scale (300‐m radius) and the landscape scale (1500‐m radius). We designed our study such that agricultural land cover at the field scale was uncorrelated with agricultural cover at the landscape scale across sites. We used model selection to determine which spatial scale better predicted aggregate bee abundance, abundance of large versus small bees and crop pollination services. We found that, overall, bees responded more strongly to field‐scale than to landscape‐scale land cover, but the scale at which land cover had the strongest effect varied by bee body size. Large bees showed a negative response to increasing agricultural cover at both scales, but were most strongly affected by the landscape scale. Small bees were negatively affected by agricultural land cover but only at the field scale, while they had a small positive response to agricultural cover at the landscape scale. Aggregate pollination services from native bees were more strongly influenced by field‐scale agricultural cover, due to the combined effects of both large and small bees responding at that scale. Synthesis and applications. Bee abundance and pollination services were strongly determined by field‐scale agricultural cover, suggesting that field‐scale set‐asides may provide significant benefits to pollination services. Further, we found that pollinators respond differently to land use depending on body size, but all groups of bees benefit from decreasing agricultural cover at the field scale. Therefore, small‐scale modifications to habitat can have significant impacts on both pollinator abundance and pollination services to crop plants.

Dissecting pollinator responses to a ubiquitous ultraviolet floral pattern in the wild

Summary Colour patterns on flowers can increase pollinator visitation and enhance foraging behaviour. Flowers uniform in colour to humans, however, can appear patterned to insects due to spatial variation in UV reflectance on petals. A UV ‘bullseye’ pattern that is common among angiosperms – UV‐absorbing petal bases and UV‐reflective apices – purportedly functions as a nectar guide, enhancing pollinator orientation and experimental evidence suggests that UV reflectance increases floral apparency to pollinators. We test the pollinator‐attracting and pollinator‐orienting functions of floral UV pattern and UV reflectance under natural conditions. Specifically, we address whether UV reflection alone, or UV pattern influences small bee and syrphid fly attraction rates (approaching, landing and foraging visits), foraging rates, and likelihood of foraging and orienting to the centre of flowers, using Argentina anserina, a species whose flowers exhibit variability in the size of the UV bullseye. We manipulated UV properties while maintaining uniformly yellow petals to create three phenotypes – uniformly UV‐absorptive, uniformly UV‐reflective, and inversed bullseye (reflective bases and absorptive apices) and compared insect visitation and behaviour to control flowers with the common UV bullseye phenotype. The presence of UV pattern increased attraction rates by both bees and syrphid flies relative to either fully UV reflective or absorptive flowers. However, only in the inverse array did the bullseye phenotype elicit higher foraging rates than the test flower. Neither the presence of pattern, nor the reversal of the common pattern influenced the likelihood of pollinator foraging or orientating to the flowers' centre during a visit. We provide some of the first evidence to suggest that flowers with spatial variation in UV reflectance may be more conspicuous to insects than those with petals that uniformly absorb or reflect UV, all of which are naturally occurring phenotypes. Further, we verify that the most common UV pattern in nature increases insect attraction and foraging rate relative to the inverse pattern. Results confirm a distance apparency function of the UV bullseye, but we argue for reconsideration of the notion that pollinators benefit from this ubiquitous floral motif through enhanced foraging efficiency.

Patterns of parasite infection in bumble bees (Bombusspp.) ofNorthernVirginia

In recent decades, severalNorthAmerican bumble bee (Bombusspp.) species have undergone precipitous declines. It is suspected that a parasite or pathogen may be responsible, yet few studies have examined the extent of parasitism and the ecology of host–parasite relationships inU.S. bumble bee populations.A season‐long survey of bumble bees in seven grassland meadows of the northernShenandoahValley andPiedmont regions inVirginia was conducted in 2011 to ascertain the local prevalence and predictors of parasitism by the internal parasitesNosemaandCrithidia, and by parasitoid conopid flies.In total, 835 bumble bees representing six species were examined. Using visual detection methods, we determined that 25% of bees were infected with parasitoid larvae, 17.4% withCrithidia, and 7.3% withNosema.Nosemainfections were more prevalent and intense in locally rare than locally common species, with the two rarest bumble bees [B. fervidus(Fabricius) andB. auricomus(Robertson)], newly suspected to be in decline, having the highest frequencies of infection (11–17.8%).Crithidiawas generally more prevalent in common bumble bee species (11–35%). With fewer than 5% of individuals infected, the two rarest species had the lowest frequencies ofCrithidia. Conopid fly larvae were more prevalent in common species.Body size significantly influenced the probability of parasitism by conopids andCrithidia. Smaller bees were more likely to be parasitised byCrithidia. Larger bees were more likely to be parasitised by conopid flies, although the largest bee species (B. auricomus) was not infected by conopids in this study.

Relationships of Bees to Host Ornamental and Weedy Flowers in Urban Northwest Guanacaste Province, Costa Rica

Ecological studies on native bees in urban tropical environments are rare, however, ever-increasing urban areas world-wide necessitate study on how many of these bees can and have adjusted to human constructs. Predictable ecological patterns that emerge from these studies can provide guidance on how future urban constructs can be designed to provide habitat for conserving and protecting native bees. These patterns can also be used for bee habitat restoration in natural and agricultural environments. An extensive survey of native bees and honey bees and their relationships to a community of 102 plant types in urban residential environments of Bagaces and Liberia in northwestern Costa Rica was conducted from 2003–2012. Bees were attracted and recorded at measurable frequencies to 82 plant genera in 41 families, the most common of which was Fabaceae. Forty-two plant types were native ornamentals; 39 were non-natives; and 21 were native weed species. Standardized bee visitation (frequency) counts, 17,000 , were used to record relationships between bees and flowers. The following data were recorded for each plant type: flowering phenology in months, type of floral reward(s) (pollen, nectar, and/or oil), main daily attraction period, and most frequently visiting bee taxa. Plant life forms included trees, shrubs, lianas/vines, herbs, and palms. Each plant group had a different seasonal flowering phenology with native ornamentals and native weeds having patterns that closely resembled the general patterns for wild plants in the dry forest. Predictable associations of certain bee taxa with each plant type emerged from the count data, which allowed for categorizing relationships into four types: small bee, diverse bee, specialized bee, and nocturnal pollination systems. Intraspecific variations in bee attraction to several plant types were also noted. Honey bees (Africanized) did not figure prominently in most pollination relationships, especially with regard to native plants. Most native bee species were generalized foragers. Beyond the urban environment, it is suggested that knowledge of predictable bee-flower relationships can also be used to restore bee habitat in disturbed environments such as deforested areas. With some imagination and outreach education, bee habitats could also be installed for some agricultural crops. Outreaching information on native bee-flower relationships at local, regional, and state levels is important for short and long-term propagation of urban (and agricultural) plants. Yet, very few outlets for transferring this knowledge currently exist in Costa Rica. A few limited options for sharing this information are discussed, including collaborative partnerships with local NGOs.

Differences of the Daily Flight Activity Rhythm in two Neotropical Stingless Bees (Hymenoptera, Apidae)

Stingless bees are mainly tropical and subtropical, eusocial bees and perform activities that are both internal and external to the nest. This study aims to investigate and compare the daily flight activities of Melipona scutellaris Latreille and Frieseomelitta doederleini (Friese). The daily flight activities of the two Meliponini species was regular for both initial and final activities and for preferential time of activity throughout the months, which may indicate the presence of a biological rhythm synchronized by the daily light-dark cycle. Temperature, light intensity and relative humidity probably influenced the rhythms of activity during the day, in a way that may act as a modulator of bee rhythms. M. scutellaris was the larger and darker bees and showed earlier activities and in lower temperatures when compared to F. doederleini, which were smaller bees.

Distribution, habitat disturbance and pollination of the endangered orchidBroughtonia cubensis(Epidendrae: Laeliinae)

The geographical distribution, population structure and pollination ecology are key aspects in the conservation and management of rare orchids. Here, we address these aspects and the main threats affecting the endangered Cuban orchid Broughtonia cubensis. This rewardless orchid is self-compatible, but pollinator dependent. However, seed production can be negatively affected by insect-mediated selfing. Three species of small bee (genera Ceratina and Lasioglossum) act as pollinators. As in the case of other nectarless orchids, we detected two species of plant producing large amounts of nectar in the area, the floral morphology of which closely resembles that of B. cubensis. The simultaneous flowering of these species could positively affect the reproductive success of B. cubensis. Nonetheless, the fitness of this orchid in natural conditions is low, possibly related to strong pollen limitation. To the problems arising from reduced fitness is added the fact that its historical distribution range has been greatly reduced in recent years. Throughout this study, we have detected dramatic reductions in the population sizes, in some cases as a result of human plundering, but also as a consequence of hurricanes. Based on the results of this study, we propose some guidelines to manage and conserve this orchid.

Molecular Basis of the Blocking Mechanism of Inwardly Rectifying Channels by Tertiapin

Ion channels are the third largest type of proteins targeted by pharmaceutical industry accounting for 10% of the currently marketed drugs. Recent advances in the 3-D structural determination of ion channel proteins coupled with highly sensitive electrophysiological assays make a compelling case for rational drug design targeting these proteins. High-resolution structure determination of inwardly rectifying Potassium (Kir) channels has thus far yielded two full-length mammalian structures. Specific blockers for Kir channels do not exist but the small bee venom peptide toxin tertiapin (TPN) targets with high affinity two Kir channels: ROMK1 and GIRK channels. Mutations of ROMK1 in the kidney cause hypotension, while, malfunctions of GIRK in the heart are associated with chronic atrial fibrillation. Modification of TPN to specifically target one or the other channel bears great therapeutic potential. We have produced structural models of TPN binding to ROMK1 and GIRK2 channels and have quantified the energies involved for each channel-toxin interaction pair. In silico mutagenesis has produced remarkably similar changes to the experimental energies of interaction between the ROMK1 channel and TPN, lending strong validation to the structural model employed. Similar studies in GIRK2-TPN interactions suggest differences in specific interactions of the toxin with each of the two channels. These models make specific predictions that are being pursued for further experimental validation. The underlying hypothesis of our approach is that differences in the interaction energies we compute can guide the design of specific TPN for different Kir channels.

Roles of scale, matrix, and native habitat in supporting a diverse suburban pollinator assemblage

Wild pollinators provide important services to both wild and human-dominated ecosystems, yet this group may be threatened by widespread anthropogenic landscape change. Suburban sprawl is one of the fastest growing types of land use change in North America, and it has certain characteristics, such as abundant floral resources, that may be beneficial for many pollinators. We examined the effects of sprawl on the wild bee assemblage of the shortgrass steppe on the Front Range of Colorado, USA. Diversity, abundance, and community composition of bees in remnant grassland fragments surrounded by suburban residential land use were compared with those in extensive, continuous grassland. No overall effect of suburbanization on bee abundance was observed, and abundance was extremely variable even within study sites. Bee species richness was positively but nonlinearly related to grassland habitat area. Bee species density was higher and more variable in suburban sites. Suburban sites and smaller habitat area were both related to relative increases in the proportions of small bee species, social bees, and solitary cavity-nesting bees in the assemblage; small suburban habitat areas also favored species of the family Halictidae over Apidae, and individuals of the genus Halictus over those of the genus Lasioglossum. In this landscape, large native habitat areas surrounded by suburban sprawl may actually increase species richness and species density over that of continuous grassland, probably by means of habitat complementation or supplementation between grassland remnants and the surrounding suburban matrix. However, at habitat areas < 20 ha, species richness became quite variable; sites < 8 ha contained less than half the species of controls.

Behaviour of pollinator insects within inflorescences of Scrophularia species from Iberian Peninsula

Several hypotheses have been proposed to explain the pattern of pollinator visits to vertical inflorescences. These range from a response to a pattern of resources to merely instinctive behaviour. In dichogamous plants, such behaviour has been associated with promoting outcrossing and avoiding geitonogamy. We here analyse behaviour of the principal pollinator groups in five protogynous species of Scrophularia with different flower sizes (S.sambucifolia, S.grandiflora, S.lyrata, S.scorodonia and S.canina), and the distribution of sexual phases along the inflorescences. The results in all cases show that pollinators follow a pattern of ascending visits accompanied by movements between flowers of the same whorl (horizontal movements). The relative frequency of these horizontal movements depends on the flower size, with a higher frequency in species with large flowers. In vertical movements of the three more common pollinator groups to several plant species (bumblebees, wasps and small bees), the behaviour was essentially independent of flower size, with bumblebees having the highest ratio of ascents to descents. Behaviour of the pollinators, together with the absence of a definite pattern of distribution of the sexual phases along the inflorescence, implies that geitonogamy is not avoided in any of the Scrophularia species studied.

Effects of body size and sociality on the anti‐predator behaviour of foraging bees

Pollinators, like most other animals, often face a tradeoff between increasing food uptake and minimising predation. An earlier model suggests that social bees should be more likely than solitary bees to adopt riskier foraging strategies in order to increase food uptake. In this paper, we extend this model by studying the effect of body size, in addition to sociality, on the predation–intake rate tradeoff. When, following standard practice, we express the foraging strategies in terms of mortality probability and net food uptake, we find that body size should have no effect on the foraging strategies of solitary bees. Social bees, on the other hand, should change their foraging preferences according to their size. Small social bees should tend to maximise food uptake, and large social bees to minimise mortality rate. Mortality, however, is the product of two terms: the probability of suffering an attack and the probability of succumbing to it. Noting that larger bees are less susceptible to succumb to a predation attempt than smaller bees, model predictions change when foraging strategies are expressed in terms of exposure to predators. Following this second approach, exposure to predators should increase monotonically with body size in solitary bees. In social bees it should reach a minimum for medium‐sized bees. We conclude that both bee body size and sociality should be considered when studying the effect of predators on resource use.

Unsteady flow field numerical calculations of a ship’s rotating Weis-Fogh-type propulsion mechanism with the advanced vortex method

The Weis-Fogh mechanism, found in the hovering flight of a small bee, is a unique and efficient lift generation. In this study, we proposed a rotating type propulsion model that applies the principle of the Weis-Fogh mechanism and calculated the unsteady flow field of the propulsion model with the advanced vortex method. The wing (NACA0010 airfoil) and channel are approximated by source and vortex panels, and free vortices are introduced away from the body surfaces. The viscous diffusion of fluid is represented using the core-spreading model to the discrete vortices. We investigated the thrust and drag coefficients, pressure field, vorticity field, velocity vector field, and average propulsive efficiency of the propulsion model by changing the rotating angle velocity. The force acting on the wing depended heavily on the directions of the thrust and drag and the thrust and drag coefficients largely fluctuated with the change in the rotating angles. The average thrust increased as the rotating angle velocity increased. The maximum propulsive efficiency was 27.9% at a calculated angle velocity. The flow field of this rotating type propulsion mechanism is unsteady and very complex because the wing rotates and moves unsteadily in the channel. However, using the advanced vortex method, it could be calculated accurately.

Possible top-down control of solitary bee populations by ambush predators

The effect of ambush predators on bee populations has so far been neglected on the assumption that predators ambushing at flowers for the arrival of pollinators are too scarce to have significant effects on population numbers. A simple mathematical model can be used to calculate the maximum predator abundance compatible with positive growth of solitary bee populations. Using published data to estimate model parameters, the model shows that medium-sized (20–80 mg dry weight) solitary bees are very sensitive to predation and their populations can hardly grow when 1–2% of flowers are occupied by ambush predators—a predator abundance well within the range reported in most studies. Smaller and larger bees, on the other hand, can easily cope with normal predator abundances: small bees do not need to visit many flowers to provision an offspring, making it unlikely that they encounter a predator, and large bees are less vulnerable to predator attacks. According to a sensibility analysis, the parameters with the greatest impact on bee population viability are the number of flowers that bees must exploit to provision an offspring and the probability that a bee, upon landing on a predator-harboring flower, is actually captured. It follows that ambush predators cannot be excluded a priori from the list of factors affecting bee diversity and abundance: small changes in the abundance of ambush predators, possibly related to changes in the availability of alternative prey, could have dramatic effects on the viability of medium-sized solitary bees.

Specialist and Generalist Bee Visitors of an Endemic Beardtongue (Penstemon caryi:Plantaginaceae) of the Big Horn Mountains, Wyoming

ABSTRACT. Insect exclusion from the flowers of Penstemon caryi showed that fruits are not produced unless pollen is moved between flowers by pollinators. We recorded over 30 species of bees visiting the flowers, and about a third of the bee species were common. Flower visitors were primarily pollen-collecting female bees, most of which also carried pollen on areas of the head that strongly implicated them as pollinators. While larger bees were generally more common on the flowers than smaller bees, there appeared to be no difference between size groups in (1) the percent of females collecting Penstemon pollen, (2) the percent of collected pollen that was Penstemon pollen, or (3) the percent of individuals that carried pollen in areas likely to effect pollination. Two long-tongued species, Anthophora ursina (Apidae) and Osmia brevis (Megachilidae), dominated the collections. These 2 species have very different host associations with Penstemon flowers: the specialist O. brevis collects pollen only from spec...

Insects, birds and lizards as pollinators of the largest-flowered Scrophularia of Europe and Macaronesia

It has traditionally been considered that the flowers of Scrophularia are mainly pollinated by wasps. We studied the pollination system of four species which stand out for their large and showy flowers: S. sambucifolia and S. grandiflora (endemics of the western Mediterranean region), S. trifoliata (an endemic of the Tyrrhenian islands) and S. calliantha (an endemic of the Canary Islands). Our principal aim was to test whether these species were pollinated by birds or showed a mixed pollination system between insects and birds. Censuses and captures of insects and birds were performed to obtain pollen load transported and deposited on the stigmas. Also, a qualitative and quantitative analysis of the flowers and inflorescences was carried out. Flowers were visited by Hymenoptera and by passerine birds. The Canarian species was the most visited by birds, especially by Phylloscopus canariensis, and its flowers were also accessed by juveniles of the lizard Gallotia stehlini. The most important birds in the other three species were Sylvia melanocephala and S. atricapilla. The most important insect-functional groups in the mixed pollination system were: honey-bees and wasps in S. sambucifolia; bumble-bees and wasps in S. grandiflora; wasps in S. trifoliata; and a small bee in S. calliantha. The species studied show a mixed pollination system between insects and passerine birds. In S. calliantha there is, in addition, a third agent (juveniles of Gallotia stehlini). The participation of birds in this mixed pollination system presents varying degrees of importance because, while in S. calliantha they are the main pollinators, in the other species they interact to complement the insects which are the main pollinators. A review of different florae showed that the large showy floral morphotypes of Scrophularia are concentrated in the western and central Mediterranean region, Macaronesia and USA (New Mexico).