Anthocorid bugs as predator of insect and mite pests on cultivated crops
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Date
2012
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
YSPU
Abstract
The present studies were primarily carried out in the laboratory and partially under field conditions at
Nauni, Solan during January 2009 to August 2011. Anthocorid bugs belonging to 3 genera and 5 species, viz.
Anthocoris confususReuter, A. dividens Bu and Zheng, Orius bifilarusGhauri, O. nigerWolff andLippomanus
brevicornis Yamada and Hirowatari, were identified on the basis of habitus, biometry and morphological
features, mainly the genitalia (copulatory tube in the female and paramere in the male). Except A. confusus, all
are being reported for the first time from HimachalPradesh and A. dividens and L. brevicornisare new records
from India. Field activity of anthocorid bugs continued from March to November on one or other flora among
the 16 plant species. Amongst these, Orius bifilaruswas the predominant one and this as well as A. dividens
were amenable for laboratory rearing. The growth pattern of O. bifilarus and A. dividensin subsequent five
nymphal stadia was heterogonic as the various body parts increased with varied growth rates and the growth
increment adhered to Brooks-Dyar law. Developmental Biology of three anthocorids A. dividens, O. bifilarus
and O. nigerwas studied. Among the 4 tested food sources for O. bifilarus, thrips from cucurbits and Corcyra
cephalonica eggs proved almost equally good for completing development in 22.8 and 24.6 days with nymphmortality of 8 and 8.7% at 25
o
C; a nymph required 55.3 thrips or 144.1eggs of Corcyrafor its development. At
28
o
C, it took 20.1 and 20.9 days (14.8 and 13.8% mortality, respectively). Trialeurodes vaporariorum and
Tetranychus urticae were poor food sources and these protracted the nymphal duration to 35.3 and 38.6 days
and mortality was very high (71.9 and73.1%). The adult bug consumed 228 Corcyra eggs and 146.4 thrips
during survival of 14.9 and 17.7 days, respectively. O. nigerwas difficult to rear on thrips and Corcyraeggs as
the nymph mortality was high (43.8 and 49.9%, respectively). However, A. dividens was easy to rear and it
completed its development on Corcyraeggs and thrips (from Bauhinia and cucurbits) in 21.8 and 25.8 days and
nymph-mortality was 15.8 and 20% respectively. It required either 137.2 Corcyra eggs or 74.6 thrips for
development and adult bug consumed 260.7 eggs or 109.8 thrips during its survival of 18.5 and 15.0 days,
respectively. Blaptostethus pallescens Poppius (a species being advocated for biological control in India)
required 208.5 Corcyra eggs for nymph development and adult consumed 296.4eggs during its survival. In all
these species, feeding potential of the females were higher than that of males. B. pallescensfailed to complete
its development on T. urticae and all nymphs died by IV-stadium. Gross morphology of the male reproductive
system of three anthocorids, A. confusus, O. bifilarus and B. pallescenswas studied and illustrated; all these
having almost round two testicular follicles in each testis. In female reproductive system of A. confusus, A.
dividens, O. bifilarus and B. pallescens each ovary contained 6-7 ovarioles. Copulatory tubes measured 1.5-1.7mm in A. confusus, 0.3mm in A. dividens, 0.07-0.12mm in O. bifilarus and 0.02-0.03mm in O. niger.
Fertility analysis revealed that for O. bifilarus intrinsic rate of increase was marginally higher onthrips than on
Corcyra eggs (r
m
=0.088 and 0.085 respectively), while for A. dividens andB. pallescensreared on Corcyra eggs
vaule of r
m
was 0.069 and 0.079, respectively. B. pallescensexhibited Holling’s type II and curvilinear type II
functional response to increasing density of Corcyra eggs as prey.
Description
Keywords
Mite pests, Anthocorid bugs, Predator of insect, Cultivated crops