Insect Pollinator And Weed Ecology In A Mango Agroecosystem
Loading...
Date
2016-03
Authors
Abdul, Nurul Huda
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Importance of wild pollinators in mango fruit production is widely known but
their distribution in the tropics and relationships with crop plants remain poorly
described. To understand the role of wild pollinators in mango production, this study
investigated the distribution of flower visiting insects (anthophiles) on inflorescences
of two mango cultivars, Mangifera indica L. cv. ‘Sala’ and ‘Chok Anan’. Abundance
of anthophiles was monitored by 15 minute hourly collection from 0800 h until 1500
h at 4-day interval from the beginning of flowering until all flowers dried up (12-28
February 2013 and 28 January 2014 – 7 March 2014). Anthophiles from 10 insect
orders consisting of 79 families, 156 genera and 15803 individual insects visited
mango flowers. Hymenoptera (38.54%) was the most dominant order followed by
Hemiptera (34.59%) and Thysanoptera (10.32%). Chok Anan attracted significantly
higher abundance of anthophiles than Sala at P < 0.05, df = 264, t = -7.490.
Anthophile abundance varied following flower availability at different sampling
occasions. More flying (mean abundance 34.98 ± 2.004) anthophiles visited flowers
during flower anthesis compared to crawling anthophiles (24.44 ± 1.973). The
gluphosinate-ammonium herbicide used to control weeds in the orchard was not
toxic to the anthophiles and their abundances on Chok Anan and Sala panicles were
not affected (P > 0.05). To verify the importance of weeds as alternate hosts for
mango anthophiles, the composition of weeds and insects in ten, 1 m2 quadrate were
recorded monthly for 14 months in 2012 and 2013. There was a significant variation
in monthly mean abundance of the weeds in this orchard (H = 36.947, df = 13, P = 0.00). Among 15 weed families recorded, Gramineae (44.87%) was the most
abundant followed by the broad leaves Compositae (22.38 %) and Acanthaceae
(8.88%). Only 17 genera of mango anthophiles had a moderate to high association
with the weed species. Out of these, 10 genera were beneficial insects (pollinator,
predator/parasitoid) while seven others were pests. The highest weed-insect
association (ρ = 0.705) was recorded between Pieris rapae and Othochloa nodosa,
Perilampus and Othochloa nodosa, Pyralinae gen.1 and Gomphrena serrata,
Episyrphus sp.1 and Acalypha siamensis. The abundance of 11 weed species were
regulated by variations in the environmental parameters in the orchard; humidity, air
temperature, wind speed and light intensity at P = 0.05. These parameters also
slightly to moderately influenced the abundance of nine genera of insects on weeds
and 12 genera of mango anthophiles. This study further investigated the importance
of wild pollinators in the production of mango fruits cultivars Sala and Chok Anan.
A pollinator exclusion experiment had shown that Chok Anan failed to produce any
fruit set in the absence of pollinators. Fruit set production was very low in natural
conditions, 4.8% and 3.1% per hermaphrodite flower for Sala and Chok Anan,
respectively. With the aid of hand pollination, fruit buds in Sala increased
tremendously to more than 100% but only 33% increase for Chok Anan.
Contribution of pollinators to total mango fruit production was estimated at 53%. Large size flies Eristalinus spp. and Chrysomya spp. were found to be efficient
pollen carriers and visited more mango flowers compared to the other flower visitors.
Description
Keywords
Pollination