Prior selfing occur in larger flowers in a mixed mating species with delayed selfing

Theory predicts that prior self-pollination (prior selfing) should not evolve in mixed mating species that enable delayed selfing. In this study, we test the hypotheais that prior selfing has evolved under severe pollinator limitation in the mixed mating species Commelina communis which can reproduce via delayed selfing. The hypothesis predicts that prior selfing occurs more frequently in populations with very low pollinator availability and/or in smaller flowers which receive infrequent visitations. We tested the predictions by comparing the degree of prior selfing among ten populations experiencing various levels of pollinator limitation and by examining a relationship between individual flower size and the occurrence of prior selfing. Populations with higher pollinator availability had higher prior selfing rate. Moreover, prior selfing occurs more frequently in larger flowers. These findings were totally opposite patterns of the predictions and the previous findings. We proposed new hypotheses that prior selfing has been maintained by the presence of reproductive interference from the congener and/or propotency in C. communis to explain our unexpected findings. We should verify potential effects of reproductive interference and propotency in future to elucidate the mystery of prior selfing in this mixed mating species with delayed selfing.

Bulbophyllum karbianglongensis (Orchidaceae, Epidendroideae), a new species from Assam, India

A new epiphytic Bulbophyllum belonging to section Cirrhopetaloides is described from tropical mixed evergreen forests of Karbi Anglong (Assam, India) with coloured photographs and line drawings. It is allied to the Bulbophyllum bicolor, B. venulosum and B. blaoense, but differs in the size and shape of pseudobulbs, the shape of the leaf blade, and flower size. A detailed description with corresponding color photos and information on the habitat is provided.

Analysis of variability of decorative features of the genus Dahlia Cav. in annual culture in the conditions of the Moscow region

In this paper, the results of the analysis of the variability of quantitative and qualitative decorative features of hybrid dahlia varieties (Dahlia x cultorum Thorsr. et Reis) used in landscaping of the Moscow region are considered. The following varieties are used in the work: Vesioly rebjata mix, Monarch mix, Butterfly Mix, Rumba white, Unwins Bedding Mix, Collarette Dandy Mix. To assess the variability, quantitative characteristics were selected: plant height, leaf size (length, width) and petiole, inflorescence diameter, tongue flower size, abundance of flowering (number of inflorescences per plant), duration of flowering; and qualitative: bush shape, compactness, type, color, glossiness, basket type, basket position relative to leaves, position, color of tongue flowers. The variability of quantitative features was assessed by calculating the coefficients of variation, the variability of qualitative features - by establishing the modalities and frequencies of occurrence. It was found that the studied varieties are the most variable in terms of plant height and the number of inflorescences on the plant, the most stable in terms of inflorescence sizes. Keywords: ANNUAL DAHLIA, BORDER VARIETIES, MORPHOLOGICAL SIGNS, QUANTITATIVE SIGNS, QUALITATIVE SIGNS, COLOR OF INFLORESCENCES, VARIABILITY OF DECORATIVE SIGNS

Catching the thief: Nectar robbing behaviour by bumblebees on naturalised Fuchsia magellanica in Ireland

Fuchsia magellanica (Ongaraceae) is a plant with a traditionally ornithopholous pollination system, pollinated primarily by hummingbirds in its native range. As a naturalised alien plant in Ireland, F. magellanica is visited largely by bumblebees, with evidence for nectar robbing behaviour of the long-tubed flowers. We aimed to investigate nectar robbing behaviour of bumblebees on F. magellanica, and in particular whether floral and pollinator traits (size) determined likelihood of nectar robbing. While F. magellanica was visited by a number of bumblebee species, only two with shorter tongue lengths were observed to rob nectar from flowers. Although there was no observed relationship between intra-specific bee body size and nectar robbing behaviour, nectar robbing was observed most frequently in the site with the highest number of bees. Proportions of robbed flowers were low overall and varied between populations, but there was a significant relationship between flower size and whether it was nectar robbed with larger flowers robbed more often. Our work suggests that floral size determines whether a flower-visitor will choose to nectar rob or not in this system. Nectar robbing may also be related to bee density which could suggest this behaviour is driven by competition for resources, or that it is learnt by observing other bees.

The Size of it: Scant Evidence That Flower Size Variation Affects Deception in Intersexual Floral Mimicry

Mutualisms involve cooperation, but also frequently involve conflict. Plant-pollinator mutualisms are no exception. To facilitate animal pollination, flowering plants often offer pollen (their male gametes) as a food reward. Since plants benefit by maximizing pollen export to conspecific flowers, we might expect plants to cheat on pollen rewards. In intersexual floral mimicry, rewarding pollen-bearing male flowers (models) are mimicked by rewardless female flowers (mimics) on the same plant. Pollinators should therefore learn to avoid the unrewarding mimics. Plants might impede such learning by producing phenotypically variable flowers that cause bees to generalize among models and mimics during learning. In this laboratory study, we used partially artificial flowers (artificial petals, live reproductive parts) modeled after Begonia odorata to test whether variation in the size of rewarding male flowers (models) and unrewarding female flowers (mimics) affected how quickly bees learned both to recognize models and to reject mimics. Live unrewarding female flowers have 33% longer petals and have 31% greater surface area than live rewarding male flowers, which bees should easily discriminate. Yet while bees rapidly learned to reduce foraging effort on mimics, learning was not significantly affected by the degree to which flower size varied. Additionally, we found scant evidence that this was a result of bees altering response speed to maintain decision accuracy. Our study failed to provide evidence that flower size variation in intersexual floral mimicry systems exploits pollinator cognition, though we cannot rule out that other floral traits that are variable may be important. Furthermore, we propose that contrary to expectation, phenotypic variability in a Batesian mimicry system may not necessarily have significant effects on whether receivers effectively learn to discriminate models and mimics.

Phenology of flowering and fruiting and effect of KNO3 and H2O2 on germination process of amorphophallus muelleri blume

Amorphophallus muelleriBlume also known as Indonesian Konjac (IK, in short) is a wild plant that spreads out in Indonesia especially in the southern part. The genus Amorphophalluscan also be found in some countries in South-East Asia. The IK tuber contains glucomannan, a compound which has high economic value as raw material in many industries such as food, drink, pharmacy, cosmetics, paper, rubber, textile, film industries and many others. The plant is easy to cultivate. Due to the economic benefit of IK tubers and to the easiness of its cultivation, this study was carried out to increase the productivity of glucomannan. The current productivity is still low compared to foreign demand. For example, in 2020 alone, according to the Ministry of Agriculture, Republic of Indonesia, only 12 % of foreign demand have been fulfilled. Therefore, there is an urgent need to increase the productivity of IK tubers. This is the main problem of this research. Its objectives were two-fold. First, was to study the effect of tuber weight on flowering percentage, flower size, and fruiting which is represented by the number of fruits and the number of seeds. Second, was to find out the right concentration of KNO3and H2O2solutions as well as the soaking time in those solutions to break the dormancy period and to increase the germination rate. For these purposes, a laboratory experiment using completely randomized design with three treatments was conducted and the collected data were analyzed using general linear model, analysis of variance and multiple comparison test. The results indicate that the tuber weight significantly affects the flowering percentage, flower size, number of fruits and number of seeds of IK. The heavier the planted tuber, the higher the flowering percentage and the larger the flower size, number of fruits and number of seeds. The response on dormancy breaking treatment indicates that there is no significant effect of soaking treatment in KNO3 and H2O2 solutions on dormancy period of the IK seeds. The KNO3and H2O2solutions have only effect on increasing the germination rate and on shortening the time period for seeds to germinate. Moreover, unlike H2O2, there is no residual effect of KNO3on seeding growth, and on weight and shape of the IK tuber. To the knowledge of the authors, these findings are unprecedented and could thus,contribute to the literature.

Effects of sexual dimorphism on pollinator behaviour in a dioecious species

Floral traits often display sexual dimorphism in insect-pollinated dioecious plant species, with male individuals typically being showier than females. While this strategy is theorized to be optimal when pollinators are abundant, it might represent a risk when they become scarce, because the disproportionately high number of visits on the most attractive sex, males, might preclude efficient pollen transfer from males to females. Here, the effect of sexual dimorphism on pollination efficiency was assessed in experimental arrays of dioecious Silene dioica that were exposed to one frequent visitor of the species, Bombus terrestris, and that differed in the magnitude of sexual dimorphism for either flower number or flower size. While flower size dimorphism did not impact pollination efficiency, we found that flower number dimorphism negatively affected the number of visits on female plants, on female flowers and on the number of female flowers visited after a male flower. However, flower number dimorphism had no effect on the number of pollen grains deposited per stigma, presumably because the decrease in the number of visits to female flowers was compensated by a higher number of pollen grains deposited per visit.

Intraspecific Convergence of Flower Size Correlates With Pollinator Size on Different Mountains: A Case Study of a Bumblebee-Pollinated Lamium (Lamiaceae) Flowers in Japan

BackgroundGeographic differences in flower size sometimes reflect geographic differences in pollinator size. However, we know little about whether this flower size specialization to the regional pollinator size occurred independently at many places or occurred once and then spread across the distribution range of the flower species. ResultsWe investigated the relationship between the local corolla tube length of flowers and morphological traits of local pollinators in 12 populations of Lamium album var. barbatum on two different mountains in the Japan Alps. Then, using 10 microsatellite markers, we analyzed genetic differentiation among the 12 populations. The results showed that local corolla tube length was correlated with the average size of relevant morphological traits of the local pollinators: corolla tube length was greater in populations visited frequently by the largest flower visitors, Bombus consobrinus queens, than it was in other populations. We also found that the degree of genetic similarity between populations more closely reflected interpopulation geographic proximity than interpopulation similarity in corolla tube length.ConclusionsAlthough genetic similarity of populations was highly associated with geographic proximity, corolla tube length varied independently of geographic proximity and was associated with local pollinator size. These results suggest that in L. album var. barbatum, long corolla tube length evolved independently in populations on different mountains as a convergent adaptation to locally abundant large bumblebee species.