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Disponibilidad de recursos florales en campos metalíferos:riqueza de especies, frecuencia de visitación y comportamiento de abejas
Abstract
A B S T R A C T
From January to March 2003, we quantified a total of 3,942 flowers of
Stachytarpheta glabra Cham. (Verbenaceae) in an ironstone outcrop, in southeastern Brazil. Our aim was to evaluate the following projections: (1) the greater the number of flowers available, the higher the frequency of bee visits to flowers of S. glabra, (2) the greater the number of flowers available, the greater will be the abundance of visiting bees and (3) if temperature, humidity and light influence the frequency of bee visits, this frequency will drop with lower temperatures, humidity and light. Nine bee species visited 313 flowers, in 91 separate visits. The total number of flowers had a positive and significant correlation with the number of bee visits, but not with the variety of bee species. Climatic variables did not exert any apparent effect on the rate of bee visits, nor the bees’ behavior. Bees performed four types of approach to flowers: the exterior of the corolla with the head directed upwards (Type 1) or head downwards (Type 2), the apex of corolla (Type 3) and the interior of corolla (Type 4). Bees spent
more time in Type 3 landings and this was the most common behavior observed (44%). This is the first time that the amount of time spent on the behavior demonstrated by different bees has been quantified for bees visiting flowers in ironstone outcrops.
Key words: Canga. Ironstone outcrops. Flower availability. Insect behavior. Serra do Rola Moça. Stachytarpheta glabra. Xylocopa sp.
... (Euphorbiaceae), Prosopis rubriflora (Fabaceae) (De Freitas et al. 2013) and Hohenbergia ramageana (Bromeliaceae) (Santana & Machado 2010). The occurrence of these longflowering species represents key resources for pollinators and florivores throughout the year as they provide predictable resources over time (Loyola et al. 2007). Such extended flowering pattern increases the number of floral visitor and pollinator species seeking pollen and nectar, improving the reproductive success of these plant species (Antonini et al. 2005;Loyola et al. 2007). ...
... The occurrence of these longflowering species represents key resources for pollinators and florivores throughout the year as they provide predictable resources over time (Loyola et al. 2007). Such extended flowering pattern increases the number of floral visitor and pollinator species seeking pollen and nectar, improving the reproductive success of these plant species (Antonini et al. 2005;Loyola et al. 2007). Finally, prolonged and synchronized flowering of plant individuals within and among populations in S. cassiae can increase the chances of crosspollination, enhancing the genetic diversity of the progeny (Kameyama & Kudo 2009). ...
The flora of the Brazilian rupestrian grasslands represents a hotspot of species richness and endemisms. Stachytarpheta cassiae (Verbenaceae), is a micro endemic species, from which nothing is known. Here, we quantified the activity and intensity of vegetative and reproductive phenophases throughout 12 months and tested for their seasonality and their relationship with local climatic variables. Both vegetative and reproductive phenophases were continuous. No seasonality was observed in the vegetative phenophases and none of them was influenced by climatic variables. Only flower buds and mature fruits’ intensities showed seasonality in February (rainy season) and July (dry season), respectively. Accordingly, increased temperature and humidity combined explained increased production of flower buds whereas decreased rainfall explained increased mature fruits. Higher intensity in flower buds may respond to similar climatic conditions as other species in the community. However, S. cassiae is much different as it continues producing flowers continuously. Higher intensity of mature fruits in the dry season is expected as their seeds are abiotically dispersed. Due to constant flower and leaf production, S. cassia may be a key species for the conservation of many vertebrate and invertebrate species and for maintaining the biogeochemical functioning of the impoverished soils of the rupestrian grasslands.
... The genus Euglossa has also been observed making legitimate visits with high frequencies in S. glabra and Saranthe klotzschiana (Körn.) Eichler (Marantaceae) (Loyola et al. 2007;Locatelli et al. 2004). In particular, Euglossa melanotricha Moure, 1967, which was frequently observed in S. cassiae, is the most abundant Euglossine species in the Cerrado (Nemésio and Faria 2004). ...
... Flowers of Stachytarpheta cassiae represent a key resource for many animal species throughout the year in these harsh ruprestian environments (Antonini et al. 2005;Loyola et al. 2007;Gélvez-Zúniga et al. 2018). Such extended flowering strategy, which is not frequent among angiosperms, allows for the constancy of a large guild of floral visitors that feed on pollen and nectar in months of low flowering in the community (Elzinga et al. 2007;Sánchez et al. 2017). ...
Knowledge on pollination biology is crucial to understand the basic aspects of sexual plant reproduction and the long-term viability of plant populations. Nowadays, the relevance of these studies on rare and micro-endemic species is ever more important, given the increasing anthropogenic pressures. Here, we characterize the floral biology and identify the pollinators of Stachytarpheta cassiae (S. Atkins), a micro-endemic species from the rupestrian grasslands of northern Minas Gerais, Brazil. Flowering of S. cassiae occurs throughout the year and flower anthesis is diurnal, with most of the flowers opening in the morning. Flowers offer nectar and pollen as rewards to a wide range of flower visitors. We observed 15 bee species, five hummingbird species, three butterfly species and one wasp species. All Euglossine bee species and hummingbird species effectively contacted the fertile whorls of the flowers and were classified as pollinators. Thus, S. cassiae appears to have a generalist pollination system. We also identified primary (Bumblebees and carpenter bees) and secondary (non-Euglossine bees and a wasp) nectar robbers and nectar thieves (butterflies). Overall, Euglossine bee and hummingbird pollinators showed significantly higher relative visitation frequency as compared to the rest of floral visitors (nectar robbers and thieves). Flowers of Stachytarpheta cassiae represent a key resource for many animal species throughout the year in these harsh rupestrian environments. Future studies should assess the nectar secretion patterns and the relative contribution of floral visitors to the reproductive success of the species.
... De modo geral, os estudos sobre interações ecológicas no QF são relativamente recentes e têm focalizado informações sobre a relação entre plantas e seus visitantes florais (e.g. Borba & Semir 2001, Jacobi & Antonini 2008, Loyola et al. 2007, insetos herbívoros (de adultos e formas juvenis de vida livre, até minadores e galhadores) e também formigas que defendem as plantas contra estes herbívoros (e.g. Vincent et al. 2002, Lanza et al. 2005, Dáttilo et al. 2014. ...
O que sabemos sobre as interações ecológicas em ambientes de canga? Talvez devido à grande diversidade vegetal, e ao componente arbóreo pouco representativo, a maioria dos estudos sobre interações ecológicas em ambientes de canga centra-se nas relações entre plantas arbustivas e seus insetos visitantes. Entretanto, diferentemente do conhecimento atual sobre a diversidade florística, as interações ecológicas são ainda mal conhecidas em campos rupestres ferruginosos, como é o caso do Quadrilátero Ferrífero (QF). Esta lacuna constitui um grande problema devido à importância desse ecossistema como mantenedor de grande número de espécies endêmicas e frente à velocidade com que as cangas estão sendo destruídas pela crescente demanda por minério de ferro (Jacobi & Carmo 2008, 2011). De modo geral, os estudos sobre interações ecológicas no QF são relativamente recentes e têm focalizado informações sobre a relação entre plantas e seus visitantes florais (e.g. Borba & Semir 2001, Antonini et al. 2005, Jacobi & Antonini 2008, Loyola et al. 2007), insetos herbívoros (de adultos e formas juvenis de vida livre, até minadores e galhadores) e também formigas que defendem as plantas contra estes herbívoros (e.g. Vincent et al. 2002, Lanza et al. 2005, Dáttilo et al. 2014). Diferentemente dos levantamentos florísticos, com registros amplamente distribuídos nas principais serras do QF, trabalhos focalizando interações foram realizados principalmente no Parque Estadual da Serra do Rola Moça (PESRM) em Belo Horizonte, Parque Estadual do Itacolomi (PEIT) em Mariana, Serra da Brígida em Ouro Preto, no Campus da Universidade Federal de Ouro Preto, e em Barão de Cocais. Estes estudos foram desenvolvidos principalmente nos campos ferruginosos sobre canga, seja do tipo nodular (mais intemperizada) ou couraçada (predominância de afloramentos rochosos). A compilação de resultados dos quase 40 estudos que contemplaram diferentes aspectos das interações ecológicas em cangas do QF foi sintetizada na forma de rede bipartida (Fig. 1). As linhas indicam o vínculo entre local de estudo e tipo de interação, e sua espessura, a quantidade relativa de estudos para esse par. O PESRM aparece como o principal local de estudos sobre interações no QF, por isso ele se encontra no topo do gráfico. Este parque é uma das raras Unidades de Conservação de Proteção Integral que atualmente tem como prioridade proteger os ecossistemas de campos ferruginosos. O mutualismo (principalmente polinização) e o parasitismo são as principais interações abordadas, mas apenas o mutualismo foi investigado em todos os locais.
... En estos casos, es posible que los colibríes actúen como robadores de néctar, como ya se ha observado en otras especies de plantas (Rojas-Nossa 2007). Las abejas carpinteras del género Xylocopa son generalistas en su forrajeo y tienden a polinizar plantas con altas densidades de flores como I. wolcottiana (Parra-Tabla & Bullock 2002, Loyola et al. 2007). En I. murucoides se observó que los Xylocopa se posan sobre el estigma y las anteras y al retirarse de las flores llevan el abdomen, el dorso y las patas cubiertas de polen, lo que los convierte en polinizadores potenciales. ...
En el presente estudio se describen algunas de las adaptaciones de las flores de Ipomoea murucoides con respecto a su interacción con los visitantes florales así como el sistema de reproducción sexual en una Selva Baja Caducifolia de México. La antesis crepus-cular, el patrón en la producción de néctar y la concentración de azúcares, el pedicelo robusto y el color y tamaño de las flores son congruentes con el síndrome floral de la quiropterofília. No obs-tante, se observó que además del murciélago Anoura geoffroyi, las flores de I. murucoides también las visitaron durante el día colibrí-es (Colibri thalassinus, Eugenes fulgens y Heliomaster constantii), abejas carpinteras (Xylocopa guatemalensis y X. tenuata) y esca-rabajos (Cerambycidae). Los murciélagos, al ser los primeros visi-tantes de las flores, resultaron ser los polinizadores más importan-tes de I. murucoides, una especie alógama y, al parecer, autoin-compatible. Palabras clave: Autoincompatibilidad, Éxito reproductor, Polinización, Quiropterofilia. Abstract Floral biology and pollination of Ipomoea murucoides Roem. & Schult. (Convolvulaceae) in Ixtapan del Oro, State of Mexico (Mex-ico) The present study describes some of the Ipomoea murucoides flowers adaptations regarding to floral visitors interactions and sexual reproduction system in a deciduous forest in Mexico. Crepuscu-lar anthesis, nectar production pattern and sugar concentration, robust pedicel, color and flower size are consistent with chi-ropterophilous floral syndrome. However, it was observed that in addition to the Anoura geoffroyi bats, the I. murucoides flowers are also visited during the day by hummingbirds (Colibri thalassinus, Heliomaster constantii and Eugenes fulgens), carpenter bees (Xy-locopa guatemalensis and X. tenuata) and beetles (Ceramby-cidae). The bats, being the first flowers visitors, turned out to be the most important I. murucoides pollinators, an apparently self-incompatible and allogamous plant.
In angiosperms selection has led to the utilization of numerous substances other than pollen and nectar that help to insure repeated visitation by pollinating animals. Here, we group the various substances into nonnutritive and nutritive rewards and discuss within each group the specific kinds that occur. In our discussion of nutritive rewards, we emphasize floral oils, lipids produced by one of two types of specialized secretory organs called elaiophores and which serve as nutritive rewards for certain New World anthophorine bees. Although discovered only within the last 15 years, the syndrome of oil production now appears to be one of the most widespread kinds of floral rewards. We report here for the first time the occurrence of oil production in the Solanaceae (Nierembergia). It is apparent that oil production has evolved independently many times, but plants which produce oils that are collected by female anthophorine bees show similarities in the chemistry of the oils and the types of structures that produce them. It is not clear whether other groups of plants reported to produce oils but which are not pollinated by anthophorine bees possess an analogous system or not.
The potential of the weed Waltheria americana for integrated management of pollinators and pests was evaluated by quantifying bee and wasp richness and amount of visitation to its flowers. Observations were made in two patches of the weed at the Campus of the Universidade Federal de Minas Gerais, Belo Horizonte, MG. Production of flowers, visitor richness and frequency of visits were estimated by inspecting 20 plants in each patch every month. We recorded a total of 37 bee and 72 wasp species. There was a significant correlation between the number of species and number of visits of wasps with the number of flowers for one of the sites. A large proportion of the bee and wasp species recorded at each site were found only one month of the year, or only a single day. Only two species of predatory wasp, Ammophila gracilis Lepeletier, 1845, and Bicyrtes angulata Smith, 1856, visited the weed during all 12 months of the study. Augochloropsis callichroa Cockcrell, 1900, was the most frequent bee, occurring during 9 months. Waltheria americana is a very succesful colonizer of cultivated lands and disturbed habitats, and by virtue of the nectar supply it offers to a large variety of bees and wasps it can be suggested as an aid in integrated pollination and pest management programs.
In an abandoned field near Ithaca, New York, bee species partitioned the available flower resources, primarily by foraging at different times of the season and by visiting different flower species. Honey bees Apis mellifera concentrated on different flower species than did native bees. Spring-flying native bees included many species adapted to forage on native flower species that bloom before the tree canopy closes. Apis mellifera outcompeted native bees at large clusters of attractive flower species such as apple and the crucifer Barbarea vulgaris. Halictus ligatus was the most common early summer halictine. This species concentrated its foraging on different flowers than did other early summer bees, probably because of differences in innate flower preferences. A profuse bloom of native goldenrods Solidago in late summer was the seasonal peak of resource abundance. Native bees must complete their seasonal cycles and enter diapause before the killing frost. They therefore foraged on early-blooming goldenrod species such as S. juncea. In contrast, honey bees overwinter as active bees within their hives. They were most common on later-blooming goldenrods, where they collected much of the nectar required for overwintering. Competition among foraging bees was probably most important in the spring at this site. Partitioning of flower species and differences in seasonal flight times resulted primarily from differences in innate flower preferences, number of generations per season, and means of overwintering.-Author
Este estudo e parte do projeto "Flora da Serra do Cipo, Minas Gerais, Brasil, A familia Verbenaceae esta representada na regiao pelos generos Aegiphila Jacq., com 3 especies, Aloysia Ort. & Palau., 1 especie, Lantana L., 1 especie, Lippia L., 8 especies, Stachytarpheta Vahl., 4 especies e Vitex L., 1 especie. Sao fornecidas chaves analiticas para generos e cspecies, descricoes. ilustracoes e dados ecologicos, fitogeograficos e fenologicos.
Recent long-term sampling studies have concluded that mid-elevational peaks in species richness identified previously may have come from the short-term sampling regimes employed, and from disturbance at lower elevations. Long-term sampling seems likely to reveal peaks at lower elevations. Analysis of 20 studies taken from the literature add the possibility that the latitude at which a study is undertaken influences the elevation of peak species richness. A study of 12 open sites in the SE USA ranging in elevation from 100-1700 m, reveals that both principal reasons advanced previously for mid-elevational peaks may be valid, if short-term sampling is employed. -from Author
If competition for pollinators is an important influence on populations of Centaurea scabiosa and C. nigra sensu lato one of the characters most likely to be affected is flowering time. Observations were made on the flowering period of several populations of the two species growing sympatrically and in isolation, and on plants from these and further populations transplanted into the Botanic Garden.
Conclusions from the study are:
The large range of flowering time seen in C. nigra may be partly attributable to differences between ssp. nigra and ssp. nemoralis and hybridization between them, but local ecological factors are important influences on some populations. Competition for pollinators between C. scabiosa and C. nigra may maintain the difference in flowering time between the two species in some areas.
The relative amounts of self- and cross-pollen deposited on stigmas depends on both the number of pollinator visits that occur within plants and the amount of pollen carryover. Data collected for Myosotis colensoi (Kirk) Macbride and compiled from a survey of the literature, reveal that pollen carryover is frequently very high (upwards of 80%) and this at least partially relieves some of the effects of geitonogamous pollinator movements. It is suggested that in some cases, selection for traits that confer a high rate of pollen carryover may occur. Aspects of the plant–pollinator interaction that are likely to influence pollen carryover are discussed.