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Thiamethoxam (TMX) is one of the most widely used neonicotinoid insecticides. However, it is unclear how TMX alters the flower-visiting behavior and seed production of Apis cerana in sunflowers. We conducted cage experiments to study the impact of chronic exposure (10 days) to TMX at sublethal concentrations of 2.4 μg/kg and 10 μg/kg on the number of flower visits per minute, seed setting percentage, 100-seed weight, and seed yield in sunflowers. Bees treated with TMX demonstrated a significantly lower number of flower visits per minute compared with the control group. Although we did not observe a significant difference in yield parameters between TMX treatments and the control group, a positive correlation was observed between yield and the bees’ flower visitation rate. Our study highlights the concern that exposure to field-level concentrations of TMX could pose a threat to the pollination services provided by A. cerana for other crops and wildflowers. [ABSTRACT FROM AUTHOR]

An increasing number of recent studies show that nectar-inhabiting microorganisms influence plant fitness by mediating interactions between plants and pollinators. However, whether the effects of nectar microbes extend beyond pollination to affect subsequent stages of plant reproduction remains largely unknown. This study aims to explore whether nectar microbes can indirectly affect fruit consumption by birds, which can be essential for seed dispersal and germination. Wild flowers of Eurya japonica trees were experimentally inoculated with the nectar-inhabiting yeast Metschnikowia reukaufii and the nectar-inhabiting bacterium Acinetobacter boissieri , both of which had been previously isolated frequently from E. japonica flowers. In this experiment, I examined whether these microbes changed female reproductive success of the understory tree. Experimental inoculation of flowers with yeasts decreased fruit and seed set compared to those inoculated with bacteria, and the control. Furthermore, fruits with higher seed set tended to be larger, and larger fruits were more likely to be consumed by seed-dispersing birds, including the Japanese white-eye Zosterops japonica, the brown-eared bulbul Hypsipetes amaurotis , and the Daurian redstart Phoenicurus auroreus. These results suggest that nectar-inhabiting microorganisms have the potential to affect plant reproduction by influencing not only plant-pollinator interactions, but also by indirectly modifying plant-frugivore interactions via changes in plant-pollinator interactions. [ABSTRACT FROM AUTHOR]

In 2021, a large population of Utricularia minor was found in a revitalized former sandpit with strongly acidic and dystrophic water in the Czech Republic. The plants in the population were robust, highly branched, flowered prolifically, and set seeds. The mean length of main shoots of robust U. minor plants was 72 cm (range 54-90 cm). Each plant had a total of 7-17 branches. Inflorescences with at least one ripening fertile capsule were 11-33 cm long and bore 6-11 flowers or capsules at different ages. However, only two ripe fertile capsules (mean 1.21) formed at maximum in one inflorescence. [ABSTRACT FROM AUTHOR]

Habitat remnants act as a source of pollinators potentially relevant for crop pollination and yield. This work analyzes how habitat loss influences pollinators, effective pollination and yield of soybean crops. The study area comprises ten sites adjacent to forest patches surrounded by a soybean matrix in central Argentina (eight sites in the season 2014–2015 and two sites in the season 2015–2016). Pollination was estimated by pollen deposition and frequency of flower visitors. Pollen deposition on stigmas and seed set were measured comparing open plants and plants with pollinator exclusion. These response variables were compared considering increasing distance to the forest edge and an increasing gradient of forest patch size. Bees were the most frequent visitors of soybean flowers, especially honeybees, but also at least three native bee species were recorded. Open plants showed higher rates of stigmatic pollen deposition than plants with pollinator exclusion, but seed set was similar. Total insect visitation rates, especially of native insects, decreased with distance to the forest edge and so did pollen deposition. Pollen deposition and seed set increased with increasing forest patch size for plants located near and far from the forest edge, respectively. Overall, our results suggest that the contribution of native pollinators from local forest patches is important for effective pollination across the landscape. Small patches of forest (approximately 1 ha.) guarantee pollinators to ensure plant yields similar to the yields of plants growing close to large patches, but only at short distances; while larger forest patches provide better pollination services for the crop at larger distances from the forest edge. However, we encourage further studies because results suggest that other factors may also influence soybean pollination and production. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Bilberry fruit abundance is crucial yet rarely addressed in capercaillie management. • Light availability increases bilberry flower numbers as well as pollinator activity. • Restoration increases light conditions but short-term effect on bilberry not evident. • More flowers and more active pollinators additively increase bilberry availability. Abstract The European bilberry, Vaccinium myrtillus L. (Ericaceae), is an important food resource for many mammals, insects and birds in forests, including the threatened capercaillie (Tetrao urogallus). For capercaillie, a sufficient amount of bilberry fruits is crucial to store enough body fat for the winter period. Studies have shown that V. myrtillus reproduction is influenced by canopy openness, but specific effects of flower availability, light conditions and pollinators on fruit production remain unclear. We therefore assessed bud, flower and fruit abundance as well as quality traits for V. myrtillus fruits under shade, semi-shade and sun conditions in 12 50 × 50 m plots in the Black Forest National Park, Germany from April to July 2017. We further observed and identified flower-visiting insects and calculated the seed set for fruits. With greater canopy openness, flower buds and fruit abundance increased. The few fruits that developed in the shade had fewer ovules compared to fruits growing under higher light availability. In the sun, seed set was highest, suggesting higher pollinator activity on these microsites. We identified five flower-visiting insect species of the genera Andrena, Bombus and Lasioglossum. The results show that canopy openness can trigger a number of additive positive effects on the number of flowers and hence potential fruits but also their quality due to an enhanced pollinator activity. Active canopy opening could therefore be used to increase bilberry availability for capercaillie. Management plans to support capercaillie populations however, should also consider the time lag between active canopy opening and flowering response in V. myrtillus. [ABSTRACT FROM AUTHOR]

Groundplum milk-vetch (Astragalus crassicarpus Nutt.) is a native legume found on gravelly to sandy prairie uplands throughout central North America. The large and fleshy fruits, or pods, of this species were consumed by indigenous people and European settlers, and are cached by rodents. Our previous research on native legumes of the northern Great Plains indicated seed predation by insects, notably bruchid beetles belonging to the genus Acanthoscelides Schilsky, was a dominant factor determining viable seed production in natural and artificial plant assemblages. However, although we have studied the reproductive biology of several species of Astragalus L., none had fleshy pods. Therefore, the objective of this study was to quantify the factors influencing viable seed production in natural populations of GPMV in South Dakota. Mature pods were collected from two natural populations on the South Dakota State University Oak Lake Field Station during July 2000 and from one natural population on the Grand River National Grassland near Lodgepole, SD, in July 2003. Pods were dissected and number of ovules that: 1) produced viable seed, 2) were unfertilized, 3) produced aborted seed, and 4) produced seeds that were predated by larvae of the bruchid beetle Acanthoscelides fraterculus (Horn) (Coleoptera: Chrysomelidae: Bruchinae) were recorded for each of the two valves of individual pods. Our results indicated average seed set, i.e., percent of ovules that produced viable seed not predated, was about 55%, averaged across populations. Unfertilized ovules were 42% of the total. Predation by the bruchid beetle occurred in about 2% of the developed seeds, with aborted seed making up the rest of the ovule total. About 35% of pods infested contained larvae, or adults that were immured within the pod while attempting to exit, presumably due to the thick and leathery layers of the ovary wall. Predispersal seed predation was a relatively minor factor in the reduction of viable seed set in GPMV in South Dakota. [ABSTRACT FROM AUTHOR]

Copyright of Basic & Applied Ecology is the property of Urban & Fischer Verlag and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Basic & Applied Ecology is the property of Urban & Fischer Verlag and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Basic & Applied Ecology is the property of Urban & Fischer Verlag and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Reproduction of dioecious trees can be seriously affected by habitat fragmentation. • Dioecious native Lithraea molleoides tree has ambophilous and apomictic seed set. • Habitat fragmentation had no effects on tree density, sex ratio and pollination level. • Similarly, seed set and progeny fitness were not affected by habitat fragmentation. • Varied reproductive strategies would confer L. molleoides reproductive resilience to fragmentation. Most of the earth's surface has been transformed by man into urbanized and cultivated areas, decreasing and fragmenting the remaining natural habitats. These changes result in decreased plant population sizes and increased isolation among remaining populations. Because dioecious plant species have male and female flowers in different individuals, they are obligately outcrossing and highly dependent on pollination vectors. Thus, reductions in population size and changes in their sex ratio after deforestation can be significantly drastic for their reproduction. While much research has been conducted assessing habitat fragmentation effects on sexual reproduction of populations of hermaphrodite species, very little is known about the effects on dioecious species. Here, we simultaneously assessed habitat fragmentation effects on the phenological patterns, sex ratios, reproductive ecology and progeny performance of the Chaco Serrano dominant native dioecious tree Lithraea molleoides. In contrast to our initial hypotheses, we found that neither conspecific flowering density, sex ratios, nor flowering phenology of L. molleoides was affected by habitat fragmentation. Lastly, progeny performance was not affected by habitat fragmentation either. Our overall findings across three reproductive seasons show that this dioecious species is resilient to changes imposed by habitat fragmentation. We discuss the particular combination of ecological traits of L. molleoides that may be conferring reproductive resilience, such as ambophilous pollination system and the capability of asexual seed production through apomixis, which may be shared by other woody native dioecious species. [ABSTRACT FROM AUTHOR]

Kudzu is reported for the first time in Canada. A population was found covering about 3500 m2 on a bank above Lake Erie near the town of Leamington, Ontario. We detected high seed viability and germination rates but no evidence that the popu-lation has been expanding beyond this site. Nonetheless, we recommend that measures be taken to prevent its continued expansion. [ABSTRACT FROM AUTHOR]