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Journal of Entomology and Zoology Studies 2016; 4(5): 548-551
E-ISSN: 2320-7078
P-ISSN: 2349-6800
JEZS 2016; 4(5): 548-551
© 2016 JEZS
Received: 20-07-2016
Accepted: 21-08-2016
Vijay Singh
Research Scholar Department of
Zoology, M. D. U., Rohtak,
Haryana, India
Vivek Goyal
Research Scholar Department of
Zoology, M. D. U., Rohtak,
Haryana, India
Suman Devi
Research Scholar Department of
Zoology, M. D. U., Rohtak,
Haryana, India
Santosh Hooda
Govt. College (W) Rohtak,
Haryana, India
Vinay Malik
Department of Zoology,
Maharshi Dayanand University,
Rohtak, Haryana, India
Correspondence
Vinay Malik
Department of Zoology,
Maharshi Dayanand University,
Rohtak, Haryana, India
Polymorphism of Cheilomenes sexmaculata
(Fabricius) (Coleoptera: Coccinellidae) in
Haryana, India
Vijay Singh, Vivek Goyal, Suman Devi, Santosh Hooda and Vinay Malik
Abstract
The study of polymorphism related to Cheilomenes sexmaculata (Fabricius) (Coleoptera: Coccinellidae)
was conducted during the year 2015-16 in Haryana, India. The family Coccinellidae is known for the
ladybird beetle species having different morphs showing variations of elytral colour patterns within and
between the species. A large number of specimens were collected by sweep nets or handpicking from the
agricultural as well as wild areas of the Haryana and six different morphs of this species were identified,
comprising of three melanic and three non-melanic forms. The different morphs of the species were
identified on the basis of the external characters and the shape of male genitalia. The pattern of the
pronotum was similar while the pattern of the elytra was quite variable in all the six types of morphs.
Thus the present study documents variable elytral colour polymorphism within C. sexmaculata in
Haryana.
Keywords: Coccinellidae, Cheilomenes sexmaculata, polymorphism, elytra
Introduction
Polymorphism is the existence of different individuals with different morphological,
behavioural or biochemical characteristics within a population. It is the result of selection over
continuous or discontinuous variations. The polymorphs having different genetic constitution
appeared due to adaption to their heterogeneous environment resulting in genetic diversity. In
many animal groups polymorphism led to have special features among individuals of a species
[1]
. In some cases polymorphism may serve to hide from predators,
[2, 3]
, while in others it gives
better chances of survival in cold conditions by increasing body temperature
[4-6]
.
Polymorphism gives a fitness advantage to the organisms in terms of feeding, mating,
defending territories and escaping from predators.
Among various types of polymorphism, colour polymorphism is a conspicuous example of
ecological and functional important polymorphism. Many species of ladybird beetle show
elytral colour polymorphism, as indicated by Harmonia axyridis, Adalia decempunctata and
Adalia bipunctata L.
[7, 8]
. Polymorphism in ladybird beetles have been studied by different
scientists at different times
[9-11]
. Polymorphism in Adaldia bipunctata was studied and
seventeen morphs were recorded for the first time from Iraq
[12]
. Similarly in Japan
geographical variations of elytral polymorphism in Cheilomenes sexmaculata was studied and
twenty morphs were reported
[13]
. The reason for various geographical gradients related to
elytral colour polymorphism in populations is not clear.
In the studies of the polymorphism, the study of ladybird beetles has occupied a special
position which is related to pattern of the dorsal surface of the head, scutellum and elytra
[10,
14]
. In its polymorphs the melanic morphs adjust better in cold conditions than the non melanic
forms
[15]
, therefore the changes in the environmental conditions provide an opportunity for the
study of morphs. Thus the environmental changes and protection from predators explains the
differences in the dark colour morphs
[16-18]
. So polymorphism may explain the relation
between different environmental factors and characters of the living organisms. The study of
available literature revealed that the information related to polymorphism in the coccinellid
beetles in Haryana is very scanty, with no specific previous record of polymorphism in
Cheilomenes sexmaculata from Haryana, India. So the present study intends to find
polymorphism in Cheilomenes sexmaculata.