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

Bio-Park

Map of BNG showing location of the study site

General view of Bio-Park

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….….

Talicada nyseus Taractrocera danna

Lycaenidae

Zizeeria maha ossa

• 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