Abundance Of Floral Visitors Research Articles

Pollinator Diversity and Foraging Behaviour of Insect Pollinators in Aonla

This study is on the diversity, abundance of floral visitors, foraging rate and speed of major pollinators in aonla orchard. Aonla flowers were observed with 22 floral visitors belonging to the Hymenoptera, Diptera, Lepidoptera and Coleoptera. Tetragonula iridipennis was the most abundant floral visitor followed by Apis cerana indica and A. dorsata. Number of flowers visited by A. cerana indica (13.46 flowers/ min) and T. iridipennis (8.26) was maximum during 1100-1200 hr. The time spent by A. cerana indica (6.24 sec/flower) and T. iridipennis (6.20) was also maximum during 1100-1200 hr.

Wild plants in hedgerows and weeds in crop fields are important floral resources for wild flower-visiting insects, independently of the presence of intercrops

The availability of diverse floral resources is crucial for the maintenance of pollinating insects and the pollination service they provide in agricultural landscapes. Ensuring plant diversity is thus essential for the maintenance and even restoration of pollinator communities. Many studies have highlighted the beneficial effects for pollinating insects of the floral resources provided either by uncultivated plants in agroecological infrastructures such as hedgerows and in crop fields, or by the addition of cultivated flowers through intercropping. However, the role of these different co-occurring vegetation types in providing floral resources to wild flower-visiting insects remains unexplored simultaneously, especially regarding their potential interacting effects. Using a paired design sampling approach, we investigated the contribution of floral resources provided by hedgerows, weeds in crop fields, and legumes intercropped with winter cereals, and their interacting effects, to the abundance of different groups of wild flower-visiting insects, plant-insect interactions and insect preferences. Our results show that the abundance of most groups of floral visitors were enhanced by the cover or species richness of floral resources provided by hedgerows or by weeds in crop fields. Interactions between uncultivated plants and insects were driven by the presence of some particular ‘preferred’ plant species offering either abundant, accessible or high-quality floral resources. By contrast, abundance of floral visitors was not enhanced by the addition of legume flowers through intercropping. The positive effects of flowering wild plants in hedgerows and crop fields remained mostly unchanged in the presence of intercrops, because of the limited contribution of legumes in providing attractive floral resources to floral visitors. Our results highlight the critical role of floral resources provided by weeds in crop fields for diverse flower-visiting insects, in addition to the floral resources provided by hedgerows. We recommend that agri-environment schemes should promote a wide diversity of floral resources at field margins through the retention of existing semi-natural elements or the sowing of wildflower mixtures. More importantly, our study encourages the seeking of alternative forms of weed management, which support a trade-off between the maintenance of pollinating insects and pollination service provision on the one hand, and crop yields and incomes for farmers on the other.

Pesticides affect pollinator abundance and productivity of sunflower (Helianthus annuus L.)

Pollination is considered one of the prime ecosystem services on the planet and is performed mainly by bees. The indiscriminate use of agricultural pesticides for pest control was evinced as one of the foremost causes of these pollinator declines. Sunflower crops demand an intense use of pesticides and, at the same time, are highly dependent on cross-pollination, essentially mediated by bees, for an increase in seed production. This study aimed to evaluate the impact of pesticides on richness and abundance of pollinators and productivity enhancement in sunflower. The study was carried out at the Água Limpa Experimental Farm located in the municipality of Uberlandia, Minas Gerais, Brazil, from May to August 2015. We conducted the study in two experimental crops of sunflower (Helianthus annuus L.). In one of them, we used the agricultural defensive bis(dithiocarbamate) for pest control, while in the other we only used a mechanical method. In both experimental crops, we quantified floral visitors during eight days, from 8 am to 4 pm. After maturation of inflorescences, we determined the mass of achenes and percentage of seed oil extracted. The abundance of floral visitors, the mass of fruits, and quantity of oil in the seeds were significantly lower after treatment with the pesticide, thus evidencing its negative effect on the sunflower productivity.

Flowering phenology and flower visitors of the Macana Palm Wettinia kalbreyeri (Arecaceae) in an Andean montane forest

The study of floral phenology patterns and floral visitors of palms is key to understanding evolutionary interactions between plants and insects. We studied the flowering pattern and floral visitors of Wettinia kalbreyeri in an Andean montane forest of Colombia. We monitored 100 adult palms throughout 1-year and observed an asynchronous flowering pattern at the population level. Collectively, those 100 individuals developed 125 inflorescences, composed of 96 staminates, 28 pistillates, and 1 androgynous. We classified 39 morphotypes of insect floral visitors, including beetles, bees, and flies. The composition and abundance of floral visitors between staminate and pistillate inflorescences were markedly different. Sap beetles – Mystrops – were the most abundant visitors in both pistillate and staminate inflorescences. We suggest that the higher production of staminate inflorescences compared to pistillate inflorescences and the availability of inflorescences throughout the year may promote a permanent and abundant community of floral visitors. This study suggests that Mystrops are associated with Wettinia species in high altitude forests, as it also occurs in Ceroxylum species.

Diurnal anthophilous fauna in Brazilian Chaco vegetation: phenology and interaction with flora

Phenology is the basis for understanding the life cycle of plants or animals throughout the year. Thus, we surveyed diurnal anthophilous fauna on plant species in the Brazilian Chaco to determine (1) groups of floral visitors and occurrence; (2) richness and abundance of fauna in relation to flowering flora and meteorological variables; (3) groups of visitors that pollinate or thieving flora; (4) distribution of herbaceous and woody strata throughout the year of flowering; (5) variation in flowering as a whole community, in the context of abiotic factors; and (6) the predominant plant families and species. We sampled eight groups of floral visitors, totalling 105 sampled species and 644 specimens. The flies and bees were the richest groups, with bees forming the most abundant group. The phenology of the fauna and flora was not clustered and exhibited a continuous and bimodal flowering. The abundance and richness of floral visitors were positively related to the quantity of plant species and flowering, as well as rainfall. Herbaceous and woody strata are important for the maintenance of anthophilous fauna throughout the year. Plant species with the highest abundance and the longest flowering period presented the highest richness and/or abundance of floral visitors. The percentage of pollination was higher than that of resource theft. Bees and flies were the main groups of pollinators, whereas flies were the main thieves. The present survey is only a starting point for future studies on the networks of interactions between plants and their floral visitors in the Brazilian Chaco.

La diversidad floral del borde afecta la riqueza y abundancia de visitantes florales nativos en cultivos de girasol

Ecología Austral, 24:94-102 (2014)Pollinator decline has been related to different types of anthropogenic disturbances, a topic largely debated in the context of global change. Within this debate, it has been stressed the importance of natural or semi-natural habitat remnants as pollinator sources for nearby agricultural fields. The SW of Buenos Aires Province is a highly-impacted and intensively-used agricultural region. However, field margins associated with country roads can provide diverse floristic resources and nesting sites for a variety of pollinators, which can eventually improve pollination and productivity of neighboring pollinator-dependent crops. Here, we evaluated the effect of floral diversity of field margins on the richness and abundance of floral visitors across 17 sunflower lots in the districts of Balcarce and Lobería. Our results indicate that floral diversity of field margins had a positive effect on the richness and abundance of native floral visitors in the adjacent crop field. As a consequence, pollination services in these agroecosystems would be promoted by increasing the amount and diversity of these marginal habitats.

La diversidad floral del borde afecta la riqueza y abundancia de visitantes florales nativos en cultivos de girasol

Ecología Austral, 24:94-102 (2014)Pollinator decline has been related to different types of anthropogenic disturbances, a topic largely debated in the context of global change. Within this debate, it has been stressed the importance of natural or semi-natural habitat remnants as pollinator sources for nearby agricultural fields. The SW of Buenos Aires Province is a highly-impacted and intensively-used agricultural region. However, field margins associated with country roads can provide diverse floristic resources and nesting sites for a variety of pollinators, which can eventually improve pollination and productivity of neighboring pollinator-dependent crops. Here, we evaluated the effect of floral diversity of field margins on the richness and abundance of floral visitors across 17 sunflower lots in the districts of Balcarce and Lobería. Our results indicate that floral diversity of field margins had a positive effect on the richness and abundance of native floral visitors in the adjacent crop field. As a consequence, pollination services in these agroecosystems would be promoted by increasing the amount and diversity of these marginal habitats.

Non-additive effects of genotypic diversity increase floral abundance and abundance of floral visitors.

BackgroundIn the emerging field of community and ecosystem genetics, genetic variation and diversity in dominant plant species have been shown to play fundamental roles in maintaining biodiversity and ecosystem function. However, the importance of intraspecific genetic variation and diversity to floral abundance and pollinator visitation has received little attention.Methodology/Principal FindingsUsing an experimental common garden that manipulated genotypic diversity (the number of distinct genotypes per plot) of Solidago altissima, we document that genotypic diversity of a dominant plant can indirectly influence flower visitor abundance. Across two years, we found that 1) plant genotype explained 45% and 92% of the variation in flower visitor abundance in 2007 and 2008, respectively; and 2) plant genotypic diversity had a positive and non-additive effect on floral abundance and the abundance of flower visitors, as plots established with multiple genotypes produced 25% more flowers and received 45% more flower visits than would be expected under an additive model.Conclusions/SignificanceThese results provide evidence that declines in genotypic diversity may be an important but little considered factor for understanding plant-pollinator dynamics, with implications for the global decline in pollinators due to reduced plant diversity in both agricultural and natural ecosystems.