Loss of pollinator diversity consistently reduces reproductive success for wild and cultivated plants

Pollination is a crucial ecosystem service, yet pollinator species diversity is declining as a result of factors such as climate change, habitat loss and agricultural intensification. While previous studies have often examined the extreme scenario of complete pollinator removal, showing negative impacts on plant reproductive success, we take a more realistic approach by focusing on the effects of decreasing pollinator diversity. Our global meta-analysis reveals a notable negative impact of reduced pollinator species diversity on plant reproductive success measures, such as seed set, fruit set and fruit weight. Notably, this effect varies across plant families, impacting both self-incompatible and self-compatible species. We also find that wild plant species suffer more than cultivated ones. Furthermore, the loss of invertebrate, nocturnal and wild pollinators has a more substantial impact than the loss of vertebrate, diurnal or managed pollinators. Overall, our findings consistently underscore the positive role of biodiversity in maintaining ecosystem functioning, highlighting the urgency of mitigating factors that lead to the decline in pollinator species diversity.

The effects of meliponicultural use of Tetragonula laeviceps on other bee pollinators and pollination efficacy of lemon

The augmentation of pollination success in lemon (Citrus limon Eureka) flowers remains contingent on the involvement of bee pollinators. With wild bee pollinator populations declining in agroecosystems, meliponiculture has emerged as a potential option in Indonesia. This study aimed to investigate the effects of meliponicultural use of Tetragonula laeviceps on diversity, foraging behavior, and monthly population of bee pollinators, as well as lemon pollination efficacy with and without meliponiculture treatment during two periods. Using scan and focal sampling methods in first and second periods, the study found that the diversity of wild bee pollinators was six species (Apis cerana, Lasioglossum albescens, Megachile laticeps, Xylocopa confusa, Xylocopa latipes, and Xylocopa caerulea), and T. laeviceps when using meliponiculture. The relative abundance and daily foraging activity of wild bee pollinators were initially reduced in the first period (March-June) and then maintained in the second period (July-October). T. laeviceps foraged on the flowers, involving specific sequences for 72 s with highest visitation rate of 0.25 flowers/h from 10:00-13:00. Light intensity was observed to be the most influential factor for bee pollinator density. Pollination efficacy results showed that meliponiculture usage has greater benefit compared to meliponiculture absence across various parameters, including fruit sets, fruit weight, yield, and estimated productivity. The effects of meliponicultural use of T. laeviceps can enhance lemon pollination efficacy while preserving the diversity of wild insect pollinators. This suggests that meliponiculture stingless bees could be a beneficial practice in agroecosystems, especially in tropical regions where wild bee populations and diversity are declining.

The positive impact of honeybee activity on fennel crop production and sustainability

This study investigates the ecological interaction between honeybees (Apis mellifera) and fennel (Foeniculum vulgare) plants, examining the mutual benefits of this relationship. Field experiments conducted in Egypt from December 2022 to May 2023 recorded diverse insect pollinators attracted to fennel flowers, especially honeybees. Assessing honeybee colonies near fennel fields showed improvements in sealed brood (357.5-772.5 cells), unsealed brood (176.3-343.8 cells), pollen collection (53.25-257.5 units), honey accumulation (257.5-877.5 units), and colony strength (7.75-10) over three weeks. Fennel exposure explained 88-99% of variability in foraging metrics. Comparing open versus self-pollinated fennel revealed enhanced attributes with bee pollination, including higher flower age (25.67 vs 19.67 days), more seeds per umbel (121.3 vs 95.33), bigger seeds (6.533 vs 4.400 mm), heavier seeds (0.510 vs 0.237 g/100 seeds), and increased fruit weight per umbel (0.619 vs 0.226 g). Natural variation in seed color and shape also occurred. The outcomes demonstrate the integral role of honeybees in fennel agroecosystems through efficient pollination services that improve crop productivity and quality. Fennel provides abundant nutritional resources that bolster honeybee colony health. This research elucidates the symbiotic bee-fennel relationship, underscoring mutualistic benefits and the importance of ecological conservation for sustainable agriculture.

Spatial and Temporal Variations in Richness, Diversity and Abundance of Floral Visitors of Curry Plants (Bergera koenigii L.): Insights on Plant-Pollinator Interactions

The reproductive success of flowering plants relates to flower-visitor communities and plant-pollinator interactions. These traits are species- and region-specific and vary across regions, pollinator groups, and plant species. However, little literature exists on the spatiotemporal variation in visitor activity, especially in India. Here, we aimed to depict the spatial and temporal variation in visitor activity on the curry plants (Bergera koenigii). Data were collected at different daytime slots from three vegetation zones (confirmed by field surveys and normalized difference vegetation index values in remote sensing)-dense, medium-density, and low-density vegetation in West Bengal, India. The visitors' richness, diversity, and abundance were higher in the area with dense vegetation. Considering daytime patterns, higher values for these parameters were obtained during 10.00-14.00 h. For most visitors, the flower handling time was shorter, and the visitation rate was higher in dense vegetation areas (at 10.00-14.00 h) than in medium- and low-density vegetation areas. The proportions of different foraging categories varied over time. Vital pollinators were Apis cerana, Apis dorsata, Appias libythea, Halictus acrocephalus, Nomia iridescens, and Tetragonula iridipennis. However, the effectiveness of pollinators remained region-specific. Therefore, it can be concluded that floral visitors' richness, diversity, abundance, and plant-visitor interactions varied spatially with their surrounding vegetation types and also changed daytime-wise.

Intercropping with Pigeonpea (Cajanus cajan L. Millsp.): An Assessment of Its Influence on the Assemblage of Pollinators and Yield of Neighbouring Non-Leguminous Crops

Intercropping is practiced in modern intensive agriculture considering many benefits, including additive crop yield. However, it may have competitive or facilitative interactions between pollinator-dependant crops. Here, we investigated the reproductive aspects of pigeonpea (Cajanus cajan). We assessed the influence of blooming pigeonpea on pollinator's assemblage and the yield of neighbouring non-leguminous crops (e.g., coriander, mustard). For these, we recorded floral visitors and the yield of the targeted crops from two types of fields-closely situated and distantly situated concerning pigeonpea plantation. Pigeonpea is autogamous, but pollinator's visits enhance fruit and seed sets. Bright, nectariferous flowers emitted several volatile organic compounds and were visited by numerous insect species. The prime pollinators of pigeonpea are carpenter bees and leafcutter bees. In contrast, halictidae, honeybees and stingless bees mainly pollinate the co-blooming non-leguminous crops (coriander and mustard). The richness and abundance of pollinators on these co-blooming crops remain similar in closely situated and distantly situated fields. As a result, the yield of the neighbouring crops is not significantly influenced by the blooming pigeonpea. Therefore, it can be concluded that planting pigeonpea in ridges of agricultural fields will be an additional agricultural output without affecting the assemblage of pollinators and yields of neighbouring co-blooming crops.

Morphological characteristics and biological cycle of the hoverfly Eristalinus arvorum (Fabricius, 1787) (Diptera, Syrphidae)

The hoverfly Eristalinus arvorum (Fabricius, 1787) (Diptera: Syrphidae), which belongs to the tribe Eristalini, is well known as a pollinating agent for crops and flowering plants in agricultural and natural ecosystems. Large quantity, wide distribution and their ecological function of the hoverfly E. arvorum make them an appropriate candidate for use as pollinators and environmental indicator species. However, little information has been known on the morphology and the biological cycle of the hoverfly. In this study, feeding experiments under artificial climate chamber and morphological qualitative and quantitative observations were carried out to study the morphology and the biological cycle of the hoverfly E. arvorum. The morphology of eggs, larvae, pupae, and adults of E. arvorum were described in detail for the first time. A complete generation of E. arvorum lasts about 30.12 ± 0.14 days, and there is no significant difference in body length between males (10.27 ± 0.29 mm) and females (11.16 ± 0.45 mm). The most noteworthy morphological features of E. arvorum are the stripes on the compound eyes, the mesonotum, and the abdomen of adults, the chorionic structure consisting of fusiform units on the egg's surface, and the anterior spiracles and pupal spiracles of the pupae. Thus, the detailed description based on morphology and life history will provide the basis for the identification, biodiversity conservation and artificial breeding of the hoverfly E. arvorum.