Host Plant Constancy in Ovipositing Manduca sexta

Many pollinating insects exhibit flower constancy, i.e. they target flower species they have already experienced and fed from. While the insects might profit from reduced handling costs when revisiting similar flowers, flower constancy, in addition, is of benefit for the plants as it guarantees pollen transfer to conspecifics. Here we investigate whether the previous experience of an insect can also result in oviposition constancy, i.e. whether ovipositing on a given plant species will drive future oviposition preference in a female insect. We show that female hawkmoths (Manduca sexta), after having oviposited on a given plant species only once, indeed will prefer this plant in future oviposition choices. As oviposition preference is even affected 24 h after the moth has oviposited on a given plant, long term memory seems to be involved in this oviposition constancy. Our data furthermore suggest that, as shown for flower constancy, ovipositing moths increase their handling efficiency by targeting those host plants they have already experienced.

Genetic and Biochemical Characterization Underpinning the Development of Floral Features that Influence Pollination – A Review

In the process of sexual reproduction in angiosperms, making viable pollen grain to land on the surface of the receptive stigma of the same flower or other flower is the key process. Major factors like both biotic and abiotic play a crucial role in the process of making pollen to reach stigma during sexual mode of reproduction in angiosperms. In nature, some of the plants pollination take place without the support of any of the above said two factors, in some of the cases transfer of pollen aided by the biotic factors viz., insects, birds, animals etc., Particularly in the process of insect or bird aided pollen transfer, secretion of volatile compound in view of attracting pollinators have multiple role. In addition to above, flower with variety of colour also play a huge role in attraction of pollinators and its aid in timely occurrence of pollination. Further, due to climate change some of the pollinator population also become extinct, under that condition through evolutionary changes plant change their phenotypic expression by that way they attract other group of pollinator in the process of sexual mode of reproduction. Only the plant able to change their adaptation through the evolutionary process or through the event of mutation based on their requirement alone able to survive. This review discusses some of the important strategy adopted by the flowering plants in view of attraction of pollinators.

Fly Pollination of Kettle Trap Flowers of Riocreuxia torulosa (Ceropegieae-Anisotominae): A Generalized System of Floral Deception

Elaborated kettle trap flowers to temporarily detain pollinators evolved independently in several angiosperm lineages. Intensive research on species of Aristolochia and Ceropegia recently illuminated how these specialized trap flowers attract particular pollinators through chemical deception. Morphologically similar trap flowers evolved in Riocreuxia; however, no data about floral rewards, pollinators, and chemical ecology were available for this plant group. Here we provide data on pollination ecology and floral chemistry of R. torulosa. Specifically, we determined flower visitors and pollinators, assessed pollen transfer efficiency, and analysed floral scent chemistry. R. torulosa flowers are myiophilous and predominantly pollinated by Nematocera. Pollinating Diptera included, in order of decreasing abundance, male and female Sciaridae, Ceratopogonidae, Scatopsidae, Chloropidae, and Phoridae. Approximately 16% of pollen removed from flowers was successfully exported to conspecific stigmas. The flowers emitted mainly ubiquitous terpenoids, most abundantly linalool, furanoid (Z)-linalool oxide, and (E)-β-ocimene—compounds typical of rewarding flowers and fruits. R. torulosa can be considered to use generalized food (and possibly also brood-site) deception to lure small nematocerous Diptera into their flowers. These results suggest that R. torulosa has a less specific pollination system than previously reported for other kettle trap flowers but is nevertheless specialized at the level of Diptera suborder Nematocera.

Asymmetrical reproductive barriers in sympatric jewelflowers: are floral isolation, genetic incompatibilities and floral trait displacement connected?

Floral visitors influence reproductive interactions among sympatric plant species, either by facilitating assortative mating and contributing to reproductive isolation, or by promoting heterospecific pollen transfer, potentially leading to reproductive interference or hybridization. We assessed preference and constancy of floral visitors on two co-occurring jewelflowers [Streptanthus breweri and Streptanthus hesperidis (Brassicaceae)] using field arrays, and quantified two floral rewards potentially important to foraging choice – pollen production and nectar sugar concentration – in a greenhouse common garden. Floral visitors made an abundance of conspecific transitions between S. breweri individuals, which thus experienced minimal opportunities for heterospecific pollen transfer from S. hesperidis. In contrast, behavioural isolation for S. hesperidis was essentially absent due to pollinator inconstancy. This pattern emerged across multiple biotic environments and was unrelated to local density dependence. S. breweri populations that were sympatric with S. hesperidis had higher nectar sugar concentrations than their sympatric congeners, as well as allopatric conspecifics. Previous work shows that S. breweri suffers a greater cost to hybridization than S. hesperidis, and here we find that it also shows asymmetrical floral isolation and floral trait displacement in sympatry. These findings suggest that trait divergence may reduce negative reproductive interactions between sympatric but genetically incompatible relatives.

Geographic mosaics of interactions via heterospecific pollen transfer may contribute to shape local and global patterns of plant diversity

Studies that aim to understand the processes that generate and organize plant diversity in nature have a long history in Ecology. Among these, pollinator-mediated plant-plant interactions that occur by altering pollinator floral preferences have been at the forefront in this field. Current evidence however indicates that plants can interact directly via heterospecific pollen (HP) transfer, that these interactions are ubiquitous, and can have strong fitness effects with implications for floral evolution, speciation and community assembly. Hence, interest in understanding their role in the diversification and organization of plant communities is rapidly rising. The existence of geographic mosaics of species interactions and their role in shaping patterns of diversity is also well recognized. However, after 40 years of research, the importance of geographic mosaics in HP intensity and effects remain poorly known, thus ignoring its potential in shaping patterns of diversity at local and global scales. Here, I develop a conceptual framework and summarize existing evidence for the ecological and evolutionary consequences of geographic mosaics in HP transfer interactions and outline future directions in this field.