FLOWERING PHENOLOGY, BREEDING SYSTEM, POLLINATORS AND FRUITING BEHAVIOUR OF PAVETTA TOMENTOSA (RUBIACEAE) ROXB. EX SM., A KEYSTONE SHRUB SPECIES IN THE SOUTHERN EASTERN GHATS FOREST, ANDHRA PRADESH, INDIA

A. Jacob Solomon Raju, M. Mallikarjuna Rao

Abstract


Pavetta tomentosa is a massive bloomer for a brief period during May-June.  The flowers are hermaphroditic, strikingly protandrous, self and cross-compatible, nectariferous and psychophilous. They possess secondary pollen presentation mechanism as a device to avoid autonomous autogamy but it does not prevent geitonogamy.  The fruit set largely occurs through geitonogamy and xenogamy.  The papilionid and pierid butterflies, and sphingid hawk moth pollinate the flowers while nectar collection.  Honey bees and blue-banded digger bees feed on pollen and effect only accidental pollination.  The nectar is sucrose-rich and contains essential and non-essential amino acids.  Birds are seed dispersal agents.  Seeds are non-dormant and germinate readily but their continued growth and establishment is subject to the availability of soil moisture and nutrients. The plant is not able to populate itself in its natural area.  Further, the local uses of flowers and leaves of this plant appear to be negatively affecting its reproductive success.  P. tomentosa serves as a keystone species for bees and butterflies because this is the only prominent and profuse flowering species during dry season in the study region.


Keywords


PAVETTA TOMENTOSA, FLOWERING PHENOLOGY, MIXED BREEDING SYSTEM, PSYCHOPHILY, ORNITHOCHORY, KEYSTONE SHRUB SPECIES.

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DOI: http://dx.doi.org/10.4462/annbotrm-13160

Annali di Botanica is published by the Department of Environmental Biology - University La Sapienza of Rome, Italy. The journal is printed by Sapienza Università di Roma - Centro Stampa Università.

ISSN: 2239-3129