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5 documents found tagged entomophily [X]
  • Title
    On the reproductive ecology of Suaeda maritima, S. monoica and S. nudiflora (Chenopodiaceae)

    Type
    Journal Article
    Description
    Floral biology, sexual system, breeding system, pollinators, fruiting and seed dispersal aspects of three Suaeda species, S. maritima, S. monoica and S. nudiflora (Chenopodiaceae) were studied. The flowers of all the three species are hermaphroditic, dichogamous, strongly protogynous with a pistillage phase during the mature bud stage and staminate phase following anthesis, self-compatible exhibiting mixed breeding systems with special adaptation for cross-pollination; but both self- and cross-pollination are vector-dependent. In all, the flowers display a mix of anemophilous and entomophilous traits. Anemophily is effective in high salt marshes while water currents bring about pollination in low salt marshes; insects pollinate the flowers while collecting the forage from pistillate and staminate phase flowers. In these species, the whole plant breaks off and rolls on the floor while shedding its diaspores. Fruits with seeds intact and/or seeds shed from fruits float on water due to their ability for buoyancy. The fruits and seeds thus disperse, settle in the entire extent of salt marshes or coastal areas and germinate in mid-summer season when salinity is very high in high and low salt marshes.
    Attribution
    A.J. Solomon Raju & Rajendra Kumar, Journal of Threatened Taxa, Vol 8, No 6 (2016); pp. 8860–8876 http://dx.doi.org/10.11609/jott.2275.8.6.8860-8876
  • Title
    Pollination ecology of Derris trifoliata (Fabaceae), a mangrove associate in Coringa Mangrove Forest, Andhra Pradesh, India
    Type
    Journal Article
    Description
    Derris trifoliata is a perennial woody climber. It blooms massively for about two weeks in July/August. The flowers are hermaphroditic, feebly protandrous, self-compatible and display a vector dependent mixed breeding system. They close back by the end of the day of anthesis. The forenoon anthesis and pollen and nectar as rewards attract daytime foragers. The nectar feeding foragers require strength to depress the keel petals in order to collect nectar; only those foragers which have the required strength to do so can collect nectar and in the process trip the floral mechanism and effect pollination. When floral explosion occurs, the pollen is somewhat exposed and the pollen feeding foragers then collect it. Both long- and short-tongued bees trip the flowers, collect nectar and effect pollination. Individual flowers that were not tripped by insects set fruit to negligible level. In open-pollination mode, fruit set rate is up to 30-31% only despite the flowers being visited by insect pollinators. Fruits mature quickly within a month. Each fruit contains 1-3 seeds against 6 linearly arranged ovules in the ovary. The fruits are leathery and possess air cavities, the characteristics of which enable them to float in tidal water. They settle at the parent plant if the site is partly or fully exposed or float for dispersal if the site is inundated with tidal water. Seed release occurs when fruits absorb water and the pericarp breaks. Seeds germinate only when they reach a suitable habitat in mangroves.
    Attribution
    A.J. Solomon Raju & Rajendra Kumar, Journal of Threatened Taxa, Vol 8, No 5 (2016); pp. 8788–8796 http://dx.doi.org/10.11609/jott.2277.8.5.8788-8796
  • Title
    Pollination biology of Eriolaena hookeriana Wight and Arn. (Sterculiaceae), a rare tree species of Eastern Ghats, India
    Type
    Journal Article
    Description
    Eriolaena hookeriana is a rare medium-sized deciduous tree species. The flowering is very brief and occurs during early wet season. The flowers attract certain bees such as Apis dorsata, Halictus sp., Anthophora sp., Xylocopa latipes, and also the wasp, Rhynchium sp. at the study sites. These foragers collect both pollen and nectar during which they contact the stamens and stigma and effect self- or cross-pollination. Nectar depletion by thrips during bud and flower phase and the production of few flowers daily at tree level drive the pollinator insects to visit conspecific plants to gather more forage and in this process they maximize cross-pollination. The hermaphroditic flowers with the stigmatose style beyond the height of stamens and the sticky pollen grains do not facilitate autogamy but promote out-crossing. The study showed that pollinator limitation is responsible for the low fruit set but it is, however, partly compensated by multi-seeded fruits. Bud and anther predation by beetles also affects reproductive success. Explosive fruit dehiscence and anemochory are special characteristics; these events occur during the dry season. The plant is used for various purposes locally and hence the surviving individuals are threatened. The study suggests that the rocky and nutrient-poor soils, the pollinator limitation, bud and anther predation, establishment problems and local uses collectively contribute to the rare occurrence of E. hookeriana in the Eastern Ghats.
    Attribution
    Raju A.J.S., Chandra P.H., Ramana K.V., Krishna J.R. (2014). Journal of Threatened Taxa 6(6) pp. 5819-5829; doi:10.11609/JoTT.o3840.5819-29
  • Title
    Entomophily, ornithophily and anemochory in the self-incompatible Boswellia ovalifoliolata Bal. & Henry (Burseraceae), an endemic and endangered medicinally important tree species
    Type
    Journal Article
    Description
    Boswellia ovalifoliolata (Burseraceae) is a narrow endemic and endangered deciduous tree species. Its flowering, fruiting and seed dispersal events occur in a leafless state during the dry season. The flowers are small, bisexual, mildly odoriferous and actinomorphic; weakly protandrous but strictly self-incompatible. While insects and sunbirds pollinate the flowers, floral characteristics suggest that entomophily is the principal mode. Both bud and flower feeding by a weevil and flower and fruit feeding by the Palm Squirrel have been found to affect the success of sexual reproduction. The Garden Lizard serves as a predator of pollinating insects, especially bees and wasps, thus influencing pollination of this tree species. Fruit set in open pollination is below 10%, rising to 34% in manual cross-pollination. Limitation of cross-pollination, space constraints for seed production from all flower ovules and availability of limited resources in rocky, dry litter of the forest floor appear to constrain higher fruit set. Mature fruits dehisce and disseminate their lightweight, papery winged seeds with the aid of wind. The study site being windy provides the necessary driving force for effective dispersal of seeds away from parent trees. Seed germination occurs following rainfall but further growth depends on soil water and nutritional status. The success rate of seedling recruitment is highly limited, and it could be due to nutrient-poor soil and water stress resulting from dry spells during the rainy season.
    Attribution
    Raju A.J.S., Lakshmi P.V., Ramana K.V., Chandra P.H. (2012). Journal of Threatened Taxa 7(4) pp. 2673-2684; doi:10.11609/JoTT.o2964.2673-84
  • Title
    Pollination biology of the crypto-viviparous Avicennia species (Avicenniaceae)
    Type
    Journal Article
    Description
    Floral biology, sexual system, breeding system, pollinators, fruiting and propagule dispersal ecology of crypto-viviparous Avicennia alba Bl., A. marina (Forsk.) Vierh. and A. officinalis L. (Avicenniaceae) were studied in Godavari mangrove forests of Andhra Pradesh State, India. All the three plant species initiate flowering following the first monsoon showers in June and cease flowering in late August. The flowers are hermaphroditic, nectariferous, protandrous, self-compatible and exhibit mixed breeding system. Self-pollination occurs even without pollen vector but fruit set in this mode is negligible. In all, the flowers are strictly entomophilous and the seedlings disperse through self-planting and stranding strategies.
    Attribution
    Raju A.J.S., Rao P.V.S., Kumar R., Mohan S.R. (2012). Journal of Threatened Taxa 15(4) pp. 3377-3389; doi:10.11609/JoTT.o2919.3377-89