Journal of Threatened
Taxa | www.threatenedtaxa.org | 26 January 2024 | 16(1): 24597–24600
ISSN 0974-7907
(Online) | ISSN 0974-7893 (Print)
https://doi.org/10.11609/jott.8804.16.1.24597-24600
#8804 | Received 28 October 2023 | Final received 01 December 2023 |
Finally accepted 25 December 2023
Twice
blooming flowers of Antigonon leptopus
Hook. & Arn. (Magnoliopsida: Caryophyllales: Polygonaceae), a
key forage source for insects during wet season in habitats disturbed by humans
P. Suvarna Raju
1, P. Srikanth 2 & A.J. Solomon Raju 3
1 Department of Health, Safety and Environmental
Management, International College of Engineering and Management, Muscat,
Sultanate of Oman, Oman.
2,3 Department of Environmental Sciences, Andhra University,
Visakhapatnam, Andhra Pradesh 530003, India.
1 suvarnarajup@rediffmail.com, 2 pallemsrikanth@gmail.com,
3 solomonraju@gmail.com
(corresponding author)
Editor: K.R. Sasidharan,
Institute of Forest Genetics and Tree Breeding, Coimbatore, India. Date of publication: 26 January
2024 (online & print)
Citation: Raju,
P.S., P. Srikanth & A.J.S. Raju (2024). Twice blooming flowers of
Antigonon leptopus
Hook. & Arn. (Magnoliopsida:
Caryophyllales: Polygonaceae),
a key forage source for insects during wet season in habitats disturbed by
humans. Journal of Threatened Taxa 16(1): 24597–24600. https://doi.org/10.11609/jott.8804.16.1.24597-24600
Copyright: © Raju et al. 2024. Creative Commons Attribution 4.0 International
License. JoTT
allows unrestricted use, reproduction, and distribution of this article in any
medium by providing adequate credit to the author(s) and the source of
publication.
Funding: Self-funded.
Competing interests: The authors declare no competing interests.
Acknowledgements: We thank Dr.
K. Venkata Ramana, Department of Botany, Andhra University, Visakhapatnam, for
field assistance.
Abstract: Antigonon leptopus is an elegant weedy species that
thrives well during wet season in habitats disturbed by humans; it shows
vegetative and reproductive events in this season. Its flowers bloom twice with pollen and
nectar presentation on day 1 and nectar presentation on day 2 for use by insects
that act as pollinators. The flowers are unspecialized with exposed sex organs
and presenting pollen and nectar which are easily accessible by the probing
insects while collecting the floral rewards and effect pollination. The field
study indicates that it acts as a key forage source for insects.
Keywords: Bees, butterflies, elegant weed,
nectar, pollen, unspecialized flowers.
Flowering plants commonly depend on insects
for pollination (Ollerton et al. 2011).
A wide variety or a few taxonomically distinct insects may visit a
single plant species for forage collection (Zych et
al. 2013). However, all visiting insect species do not act as pollinators since
some insects use floral sources without providing pollination service to the
plant species they visit for forage collection (Irwin et al. 2010; Castro et
al. 2013). Further, the insect species that effect pollination are not equally
efficient in providing the pollination service (Schemske
& Horvitz 1984; Rosas-Guerrero et al. 2014) and their efficiency in forage
collection is often attributed to the size, morphology, hairiness of
mouthparts, and legs (Armbruster et al. 2014). Baker & Baker (1982, 1983)
described two categories of flowers, ‘bee and butterfly flowers’ and ‘true
butterfly flowers’; in the former category, the flowers are characterized by
short-tubed corolla with hexose-rich nectar while in the latter category, the
flowers are characterized by deep, narrow corolla tubes with relatively copious
sucrose-rich nectar. With this backdrop, the present study was contemplated to
investigate the flowers of Antigonon leptopus with reference to their role as key forage
source for insects, especially bees and butterflies during wet season in
habitats disturbed by humans.
Materials and Methods
Antigonon leptopus growing in vacant spaces surrounded by
residential areas of Andhra University campus and along roadways in
Visakhapatnam, Andhra Pradesh, India, was selected for the present study during
June–December 2022. The field study was conducted on the flowering season,
floral structural and functional aspects, anthesis, floral rewards produced,
and flower visitors, their foraging time and foraging activities on this plant.
The data collected on these aspects were examined to know the value of this
plant as a forage source for visiting insect species during wet season in areas
of human disturbance.
Observations and
Discussion
Antigonon leptopus is an elegant creeper which grows and
flowers vigorously during rainy season from June to October (Image 1a). The
inflorescence is a compound umbellate cyme which produces several flowers daily
during 0630–0830h (Image 1b). The flowers are hermaphroditic, small, showy,
pink in color and cup-like. They close back by 1500 h on the first day and
re-bloom on the next day along with the new flowers but close back again by
1500 h and remain so until they fall off. They are staminate on the first day
with the downward curling of stigmas and pistillate on the second day with
complete pollen shedding from the anthers. The flowers produce nectar in day 1
flowers only indicating that day 1 flowers provide both pollen and nectar while
day 2 flowers provide left over nectar to insect foragers.
A variety of taxonomically different insects
consisting of bees, a wasp and butterflies foraged on the flowers of A. leptopus daily during daylight hours from morning to
evening. The bees were Apis dorsata (Image 1c), A. cerana
(Image 1d), A. florea (Image 1e), Trigona iridipennis (Image
1f), Xylocopa latipes
(Image 2a), and X. pubescens. The wasp
included only one species of the genus Rhynchium
(Image 2b). The butterflies were Pachliopta
aristolochiae, P. hector, Graphium
agamemnon, Catopsilia pomona (Image 2c), C. pyranthe,
Eurema hecabe, Acraea violae, Euthalia aconthea, Precis iphita, Danaus chrysippus, Euploea core, Hypolimnas bolina (Image 2d),
Junonia lemonias (Image
2e), Jamides celeno
(Image 2f), and Euchrysops cnejus (Image 2g) (Table 1). The insects visited day 1
and day 2 flowers indiscriminately to collect pollen and/or nectar. Bees
obtained both pollen and nectar from day 1 flowers and only left
over nectar from day 2 flowers; the nectar availability in day 2 flowers
depended on the utilization level of nectar by insects in day 1 flowers. The
wasp and butterflies collected only nectar and use day 1 and day 2 flowers as
nectar sources. Since flowers are small and cup-like with sex organs well
exposed characterizing unspecialized floral syndrome, all foraging insects
reached pollen and/or nectar easily and while collecting the forage they
contacted the sex organs and pollinated the stigmas automatically (Burkill 1916; van der Pijl 1937).
Raju et al. (2001) reported that since the flowers display temporal dioecy with
either male or female phase at any given day, there is no possibility for
self-pollination within the flower but facilitate self-pollination
(geitonogamy) within the plant. The plant with intense flowering during wet
season and unspecialized flowers is a key source of pollen and nectar for bees
and of nectar for wasps and butterflies in habitats disturbed by humans.
Conclusion
The study indicates that A. leptopus with flowers opening twice is a key forage
source for insects during wet season in areas where human disturbance results
in decimation of plant cover and reduced species diversity.
Table 1. List of flower
visitors feeding on pollen/nectar of Antigonon
leptopus.
|
Order/ Family |
Scientific name |
Common name |
Forage collected |
Foraging time |
|
Hymenoptera |
||||
|
Apidae |
Apis dorsata F. |
Rock Honey Bee |
Pollen and Nectar |
0730–1700 |
|
|
Apis cerana F. |
Asian Honey Bee |
Pollen and Nectar |
0730–1700 |
|
|
Apis florea F. |
Dwarf Honey Bee |
Pollen and Nectar |
0730–1700 |
|
|
Trigona iridipennis Smith |
Stingless honey bee |
Pollen and Nectar |
0800–1630 |
|
|
Xylocopa latipes Drury |
Carpenter bee |
Nectar |
0800–1700 |
|
|
Xylocopa pubescens Spinola |
Carpenter bee |
Nectar |
0800–1700 |
|
Vespidae |
Rhynchium sp. |
Potter wasp |
Nectar |
0830–1630 |
|
Lepidoptera |
||||
|
Papilionidae |
Pachliopta aristolochiae F. |
Common Rose |
Nectar |
0830–1530 |
|
|
P. hector L. |
Crimson Rose |
Nectar |
0830–1530 |
|
|
G. agamemnon
L. |
Tailed Jay |
Nectar |
0830–1530 |
|
Pieridae |
Catopsilia pomona F. |
Common Emigrant |
Nectar |
0830–1530 |
|
|
C. pyranthe L. |
Mottled Emigrant |
Nectar |
0830–1530 |
|
|
Eurema hecabe L. |
Common Grass Yellow |
Nectar |
0830–1530 |
|
Nymphalidae |
Acraea violae F. |
Tawny Coster |
Nectar |
0830–1530 |
|
|
Euthalia aconthea Cr. |
Common Baron |
Nectar |
0830–1530 |
|
|
A. merione
Cr. |
Common Castor |
Nectar |
0830–1530 |
|
|
Junonia lemonias L. |
Lemon Pansy |
Nectar |
0830–1530 |
|
|
Precis iphita Cr. |
Chocolate Pansy |
Nectar |
0830–1530 |
|
|
Danaus chrysippus L. |
Plain Tiger |
Nectar |
0830–1530 |
|
|
Euploea core Cr. |
Common Indian Crow |
Nectar |
0830–1530 |
|
|
Hypolimnas bolina L. |
Blue Moon |
Nectar |
0830–1530 |
|
Lycaenidae |
Jamides celeno Cr. |
Common Cerulean |
Nectar |
0900–1500 |
|
|
Euchrysops cnejus F. |
Gram Blue |
Nectar |
0900–1500 |
For images
- - click here for full PDF
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