MSc

The present investigation on “Stingless bee foraging pattern in ornamental plants” was
conducted at the Department of Agricultural Entomology, College of Agriculture, Vellayani,
during 2020-2022. The objective of the study was documentation of the foraging pattern of
stingless bees in nectariferous and polleniferous ornamental plants and preparation of floral
calendar. Flowers were observed from identified ornamental plants at full bloom stage and their
flowering period and floral characteristics were studied. Foraging activity of stingless bee was
studied and observations were recorded from 0700 h to 1800 h from September 2021 to August
2022.
A total of 20 ornamental plant species were identified on the basis of stingless bee
foraging for nectar and pollen of which, 9 plant species were found producing flowers year
round and remaining as seasonal. Major nectar producing plants were identified as coral vine
(Antigonon leptopus Hook. and Arn) and scarlet bush (Hamelia patens Jacq). Pollen producing
plants were identified as moss rose/sun plant (Portulaca grandiflora L), water lily (Nymphaea
sp), rose (Rosa spp), scented rose (Rosa bourboniana L), ornamental palm (Syagrus
romanzoffiana cham), lemon vine (Pereskia aculeate L), marigold (Tagetes erecta L) and
sunflower (Helianthus annuus I). The ornamental plants providing both nectar and pollen were
found to be hibiscus (Malvaviscus arboreus B, Hibiscus rosa-sinensis L), peacock plant
(Caesalpinia pulcherrima L), chinese powder puff (Combretum constrictum L), chinese ixora
(Ixora chinensis L), cape honey suckle (Tecoma capensis L), peregrina/ spicy jatropha
(Jatropha Pandurifolia L) and euphorbia (Euphorbia mili L).
Among the ornamental plants foraged by bees, the predominant family was Asteraceae
followed by Rubiaceae, Malvaceae and Euphorbiaceae. The majority of bee flora were of
strong orange, yellowish white followed by strong red and vivid reddish orange and tubular
and cup-like shapes.
Studies on foraging activity of stingless bee revealed that the peak activity was recorded
during January and March with peak foraging activity from 1000 h to 0100 h. Among the year
round flowering plants, maximum foraging rate was observed in Antigonon leptopus and
among seasonal flowering plants, it was Syagrus romanzoffiana. Longest time spent by
foragers was recorded as 30.44 sec during 1000-1200h of the day. Maximum time spent was
observed in Nympheae sp. followed by Malvaviscus arboreus.
Relationship between foraging rate and weather parameters viz temperature, relative
humidity, wind velocity, rainfall and sunshine hours were done. Significant positive correlation
was observed with temperature and number of foragers in case of Antigonon leptopus (0.221),
Caesalpinia pulcherrima (0.271), Portulaca grandiflora (0.402), Jatropha pandurifolia
(0.454) and Syagrus romansoffiana (0.213). Significant negative correlation was observed
between relative humidity and number of foragers in case of Antigonon leptopus (-0.157),
Hamelia patens (-0.216), Nymphaea sp. (-0.356), Caesalpinia pulcherrima (-0.256), Portulaca
grandiflora (-0.295), Jatropha pandurifolia (-0.311), Malvaviscus arboreus (-0.142),
Combretum constrictum (-0.293) and Syagru sromansoffiana (-0.401). Significant negative
correlation was found between rainfall whereas significant positive correlation was recorded
with sunshine hours and foraging rate.
Thus in this study two nectar producing plants, eight pollen providing plants
and 10 nectar and pollen producing ornamental plant species were identified. The foraging
activity of bees varied in a day with the peak foraging activity during 1000 h to 0100 h. Bee
floral calendar was prepared by using data of year round observation which can aid the farmers
in providing the identified bee flora in particular month so that the bees can exploit these
resources available in their surroundings.