ISSN 1067-4136, Russian Journal of Ecology, 2016, Vol. 47, No. 3, pp. 310–314. © Pleiades Publishing, Ltd., 2016.
Pollinating Efficiency of Native Bee Pollinators of Pigeonpea
(Cajanus cajan) in Nagaland
A. K. Singh
AICRP (Honey Bees and Pollinators), Department of Entomology, Nagaland University,
School of Agriculture Sciences and Rural Development, Medziphema, Nagaland 797 106, India
Received October 5, 2015
Abstract—Present study was carried out to determine pollinators’ diversity and their efficiency with modular
approach; foraging behaviour, number of loose pollen adhered on their body and number of pollen deposited
on the stigma. The observations explicitly indicate that Megachile spp., Xylocopa tenuiscopa, Amegilla zonata
and Nomia sp. were true pollinators and out of these, Megachile spp. were key pollinators of pigeonpea.
Among megachilids, Megachile lanata was the most efficient pollinator. Sufficient pollination meticulously
accomplished in pigeonpea by true pollinators under this agro-ecological region.
Keywords: pollinators, Cajanus cajan (l.) Mill sp., pollinator diversity, pollinator efficiency, Megachile spp.
Pigeonpea is often cross pollinated crop, with 20–
40 per cent occurrence of cross-fertilization and its
flowers are pre-anthesis cleistogamy (Saxena, 2006).
Onim et al. (1978) reported that pigeonpea anthers
dehisce during the bud stage while pollen grains ger-
mination do not start until the f lower starts to wither,
i.e. 24–28 h after dehiscence. The stigma was found to
be receptive 48 h before flower opening and continued
up to 4 days after flower opening (Luo et al., 2009).
The delay in pollen germination and stigma receptivity
remains even after the flowers open which shows great
promise for insect pollinators. Datta and Deb (1970)
reported that when pollinated with pollen from the
same flower, pollen tube growth within the style is very
slow, where it takes 54 h to reach the base of the ovary.
Reddy and Mishra (1981) reported that the percentage
of “selfs” was negligible when f lower buds were polli-
nated with foreign pollen. The long stamens are uti-
lized in insect-aided out-crossing and frequent visits
of pollen-carrying insects across various genotypes
leading to natural crosspollination (Saxena, 2006).
Such mechanisms in pigeonpea have sufficient scope
for insect pollination with foreign pollen and thus
favoring out-crossing. Pigeonpea flower’s reproduc-
tive organs viz. anthers and stigma are covered by two
joint petals (keel). Therefore, to accomplish the polli-
nation, pollinators must open the keel and let their
scopa touch the reproductive organs.
The most common insect visitor may not be the
most effective pollinator (Ivey et al., 2003). The
flower- visitor interactions are mutualism whereas
some insect visitors may only extract nectar from the
flower without accomplished pollination and repre-
sent themselves as nectar robber (Castro et al., 2008).
Insect pollinators also carry different quantities of pol-
len on their bodies (Adler and Irwin 2006) and differ
in their flower visitation rates when foraging (Vicens
and Bosch 2000; Monzon et al., 2004). The evaluation
of pollinator efficiency has been incessant for about
four decades in different crops on the basis of their few
abilities, visitation rates and number of pollen adhered
on body where the number of pollen deposition on
stigma by pollinator is the most important factor but
was missing. Hence, present investigation was envis-
aged to substantiate and determine the diversity of key
insect pollinators of pigeonpea and their efficiency on
the basis of visitation rate, number of loose pollen
adhered on the body and pollen deposited on stigma.
MATERIALS AND METHODS
The experimental material consisted of long dura-
tion pigeonpea variety BRG-2 and their insect polli-
nators. The research trial was accomplished at
SASRD Research Farm of Nagaland University, crop
shown onset of monsoon (June) consecutively for two
seasons during 2011 and 2012. The site is located in the
foot hills of Pauna hills in Himalayan range at an alti-
tude of 310 m above mean sea level (msl), situated at
25°75′ N latitude and 93°86′ E longitude. The area has
sub-tropical climate with warm summers and cold
The article is published in the original.