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ANALYSIS OF BUTTERFLY COMMUNITIES IN RELATION TO THE TREE DENSITY AND
CANOPY COVER IN BIO-PARK OF BANGALORE UNIVERSITY, BANGALORE,
KARNATAKA, INDIA
SHASHIKUMAR. L AND VENKATESHA. M.G
Department of Zoology
Bangalore University
Bangalore –560 056
INTRODUCTION• Butterflies are colourful insects
• Bioindicators
• Pollination
• Food chain
• Ornamentation & Decorative
• Entertainment & Amusement
• So far no detailed studies on occurrence, activities & seasonal abundance of butterflies – urban areas –plains – India
Hence, the present study – carried out in Bio-Park of Bangalore University, Bangalore
METHODOLOGY• Regular surveys – in 486ha. of Bio-Park of
Bangalore University of six selected sites to record butterfly spp.
• Sampling period: Once a fortnight from Jan. 2008 - Dec. 2009
Data transferred in to month wiseMonths – converted to seasons
• Sampling method: Linear transect (Pollard 1977, 1982) & Visual counting
• Survey: Tree spp. – Identified, their no. –recorded
• Butterfly population in relation to tree density & canopy cover – studied
• Seasonal abundance of butterflies – studied
• Canopy closure of each plot – calculated using “histogram” option on – software Adobe Photoshop
Graphium agamemnon Graphium doson liades polymnestor
Pachliopta aristolochiae Pachliopta hector Papilio demoleus Papilio polytes
PAPILIONIDAE
Danaus chrysippus Danaus genutia Euploea core Tirumala septentrionis
DANAIDAE
ContinuedContinued….….
RESULTS AND DISCUSSION
Elymnias hypermenstra Melanitis leda Melanitis leda Acraea violae(Dry season form) (Wet season form)
SATYRIDAE ACRAEIDAE
Ariadne merione Calysisme visala Charaxes fabius Euthalia aconthea
Euthalia nais Hypolimnas bolina Hypolimnas misippus (♂) H. misippus (♀)
Junonia hierta Junonia iphita Junonia lemonias Junonia orithya
Continued….Continued….
Mycalesis perseus Mycalesis perseus Neptis hylas Phalantha phalantha(Dry season form) (Wet season form)
Polyura athamas Notocrypta curvifascia
NYMPHALIDAE HESPERIIDAE
Anaphaeis aurota Catopsilia pomona Catopsilia pyranthe Catopsilia pyranthe(Dry season form) (Wet Season form)
Colotis eucharis Colotis eucharis Colotis fausta Delias eucharis(Dry season form) (Wet season form)
Continued….Continued….
Hebomoia glaucippe Huphina coronis Ixias marianne Leptosia nina (Intermediate form)
Pieridae
Pareronia valeria Cepora nerissa
Actolepis liliacea Augiades subhyalina Castalius rosiman Chilades laius
Chrysophanus sp. Curetis thetis Jamides celeno
Kibreeta libythea Lycaena omphisa Lycaenopsis jynteana L. oreana
ContinuedContinued….….
• A total of 64 spp. of butterflies – eight families – recorded during – study period
• 471 trees belong to 28 diff. families were identified from six plots
Plot No. Tree density (%) Canopy closure (%)
1 7.773 94.500
2 10.777 89.910
3 18.727 89.530
4 19.434 90.760
5 31.978 87.970
6 11.307 93.500
Percent of the tree species and canopy closure of the study plots in Bio-Park
• The greatest diversity of canopy trees was found in Plot 5 (31.978%), whereas the least diverse community was found in Plot 1 (7.773%)
• Habitat heterogeneity is often associated with spp. diversity
• Canopy closure ranges from 87 to 94%
• Canopy ht. ranges from ~ 30 – 40 ft. with occasional emergent reaching 45 ft.
• Tree ht. & length of - live crown do not affect –estimates of canopy cover, whereas canopy closure increases as – trees become taller
• Out of 64 – butterfly spp. 31 spp. were shade loving butterflies & they preferred canopy
• They were +vely correlated with canopy closure
• It is reported – trees constitute a better habitat for urban spp. by providing greater shade & more effective cooling
• Delias eucharis (Pieridae) & Euploea core(Danaidae) – found flying under the canopy of Ficus bengalensis trees, whereas Elymnias hypermenstra preferred Cocos nucifera for shade
• It is noted – fast fliers especially pierids generally preferred - canopy, whereas slow fliers preferred low stratum
0
5
10
15
20
25
30
35
40
45
50
Winter Summer Monsoon Common
throughout the
year
no.
of F
amily
/Gen
us
0
10
20
30
40
50
60
70
80
90
No.
/% s
peci
es
No. of family No. of genus No. of species % species
Seasonal variations of butterfly fauna in Bio-Park during 2008-09
• 43 spp. – Winter
38 spp. – Summer
50 spp. – Monsoon
25 spp. – Throughout the year
• Seasonal variation in butterflies –availability of host plants, suitable temp. & humidity.
Hypolimnas misippus Castalius rosimon
Polyura athamas Pachliopta hector
WPA – Schedule-I spp. recorded in the Bio-Park
• The studies indicated – the butterflies spp. sampled in closed canopy had more restricted geographical distribution than those found in open area
• Out of 64 – butterflies, about 50% of butterflies depend on canopy & others found in open areas
• Bio-Park of BU harbours a modest no. of butterfly spp.
•The butterflies – particularly sensitive to climate
• Large no. of butterfly spp. observed during monsoon period due to suitable temp. humidity & availability of larval host plants & adult nectar plants
CONCLUSIONS
Ø The nature of vegetation, humidity, sunshine,
availability of water source etc. are factors –
determine - survival of a spp. in a particular
habitat
Ø Hence, by maintaining more trees, nectar & host
plants, it is possible to conserve various butterfly
spp. in the Bio-Park of Bangalore University