RESEARCH ARTICLE

On the Quantification of Information Content of Flower-InsectInteraction by the Species Diversity Indices: A Case Studyin Flower Visiting Hymenopterans

Panchali Sengupta • Narayan Ghorai •

Subir Bera

Received: 14 March 2011 / Revised: 24 April 2012 / Accepted: 15 May 2012 / Published online: 17 June 2012

� Zoological Society, Kolkata, India 2012

Abstract Several interesting views have been suggested

regarding the kind of biological communication systems

that exists between the insects and plant community as a

whole. Our study attempts to measure the information

content transmitted through different floral attributes which

in turn is received by the visiting hymenopteran insects.

Ten different floral patches bloomed in different times of

the season for a period of 3 years had been studied in the

agricultural tracts. We have used the Shannon Wiener

Function and Brillouin’s Index in order to ascertain the

probable information content of such interaction. Higher

values of information content obtained in case of the cul-

tivated food plants point towards the presence of a greater

preference for these floral patches by the different foraging

insect species compared to the wild and cultivated horti-

cultural species.

Keywords Flower-insect interaction � Species diversity

index � Hymenopterans � Information content of biological

communication

Introduction

Insect-plant interactions have been studied from different

points of views (Heinrich and Raven 1972; Gilbert and

Raven 1975; Kevan and Baker 1983; Matthews and

Kitching 1984; Price 1984; Strong et al. 1984; Barth 1991).

Any kind of interactive study may be viewed as the out-

come of biological communication at any level of com-

munity. Most of the insects are largely dependant on plants

exploring arrays of plant resources for their survival as a

whole. Given that some amount of information are trans-

mitted through different types of floral attributes viz.,

colour, shape, scent, amount of nectar, pollen grain etc.

from a plant species to a flower visiting insect intending to

explore floral resources. But the question here arises on

how the degree of such interactions can be measured

quantitatively. At the community level, the quantification

of such information content of communication, if any, had

never been attempted. In the present study the species

diversity indices of some flower foraging hymenopterans

by Shannon-Wiener Function (Shannon and Weaver 1949)

and Brillouin’s Index (Krebs, 1991) have been used in

order to ascertain the probable information content of

flower-hymenopteran interactions.

Materials and Methods

Ten different floral patches bloomed in different times of

the seasonal cycles of the years 2008–2010 had been

studied. The study area is situated in the adjacent agricul-

tural tracts (Kamalgazi, Narendrapur—21.94�N, 88.44�E

of district: South-24 Parganas) of Kolkata city, West

Bengal, India with a mean annual temperature of 26.8 �C

and annual rainfall of 1,582 mm. The plant species

P. Sengupta � N. Ghorai

Department of Zoology, West Bengal State University,

Berunanpukaria, Malikapur, Barasat, District-24 Parganas

(North), Kolkata 700126, West Bengal, India

e-mail: panchali_17sg@yahoo.com

N. Ghorai

e-mail: nghorai@gmail.com

S. Bera (&)

Department of Botany, University of Calcutta, 35, Ballygunge

Circular Road, Kolkata 700019, West Bengal, India

e-mail: berasubir@yahoo.co.in

123

Proc Zool Soc (Jan-June 2012) 65(1):57–60

DOI 10.1007/s12595-012-0029-0

TH

EZ

O

OLOGICAL SOC

IET

YKO LK ATA

belonging to different floral patches studied were Brassica

nigra L. (Brassicaceae), Helianthus annuus L. (Astera-

ceae), Ageratum conyzoides L. (Asteraceae), Eupatorium

odoratum L. (Asteraceae), Tagetes patula L. (Asteraceae),

Mikania cordata (Burm. F.) B. L. Rob. (Asteraceae), Cu-

curbita maxima Duchesne (Cucurbitaceae), Lantana

camara L. (Verbenaceae), Polianthes tuberosa L. (Agav-

aceae) and Ixora coccinea L. (Rubiaceae). The hymenop-

teran insect species surveyed during the study period were

Apis dorsata Fabr., Apis mellifera Linnaeus, Apis cerana

indica Fabr., Apis florea Fabr., Andrena ilerda Cameron,

Andrena leaena Cameron, Anthophora zonata (Linn.),

Xylocopa pubescens Spinola, Xylocopa fenestrata (Fabr.),

Osmia adae Bingh, Bombus orientalis Smith, Trigona

thoracica Smith, Camponotus compressus (Fabricius),

Megachile nana Bingh, Megachile femorata Smith and

Tetraponera rufonigra (Jerdon). The diurnal, aerial insects

were collected with an insect net having 12 inches diam-

eter. From each patch a mean of 25 samples (n = 25) were

considered. Among the sampled insects only the various

species of hymenopteran insects, mostly dependant on

floral resources, were isolated and preserved for identifi-

cation and statistical analyses. Floral-patch wise species

diversity indices of different sampled hymenopterans were

ascertained by Shannon-Wiener Function and Brillouin’s

Index. Since, base 2 log was used; the units of information

content of sample were bits per floral patch.

The formula and their explanations are as follows:

Shannon-Wiener Function:

H0 ¼Xs

i¼1

pið Þ log2pið Þ

where H0 = information content of the sample; (bits/patch)

= index of species diversity; S = number of species; pi =

proportion of total sample belonging to the ith species

Brillouin’s Index:

H ¼ 1=Nlog2 N!= n1!ð Þ n2!ð Þ n3!ð Þ. . .½ �

where H = Brillouin’s Index; N = total number of indi-

viduals in entire collection; n1 = Number of individuals

belonging to species 1; n2 = Number of individuals

belonging to species 2

Results

The floral attributes of ten studied floral patches and other

related information are shown in Table 1. Patch wise

species diversity indices by both the Shannon-Wiener

Function and Brillouin’s Index are presented in Table 2,

Table 1 Detailed floral attributes of each floral patch

Floral patches Floral attributes

Colour Shape Nature of Patch:

(a) Cultivated as monofloral

patch or mixed patch

(b) Wild: Sporadic or Contiguous

Resource:

Nectariferous/

Polleniferous/

both nectariferous

and polleniferous

Position of

anthers:

exposed

or concealed

Brassica nigra L. Yellow Cruciform Cultivated as monofloral patch

or mixed patch

Nectariferous Exposed

Helianthus annuus L. Yellow Ligulate and

tubular

Cultivated as monofloral patch

or mixed patch

Nectariferous Concealed

Cucurbita maxima Duchesne Yellow Campanulate

(wide)

Cultivated as monofloral patch

or mixed patch

Nectariferous Exposed

Lantana camara L. Yellow,

orange,

red white etc.

Rotate Wild: Sporadic or Contiguous Nectariferous Concealed

Ageratum conyzoides L. Bluish white Tubular Wild: Sporadic or Contiguous Nectariferous Concealed

Eupatorium odoratum L. White Tubular Wild: Sporadic or Contiguous Nectariferous Concealed

Mikania cordata (Burm.f.)

B.L.Rob.

White Funnel form Wild: Sporadic or Contiguous Nectariferous Concealed

Polianthes tuberosa L. White Funnel form Cultivated as monofloral patch

or mixed patch

Nectariferous Concealed

Ixora coccinea L. Reddish Rotate Cultivated as monofloral patch

or mixed patch

Nectariferous Exposed

Tagetes patula L. Yellow,

brown,

white etc.

Ligulate and

tubular

Cultivated as monofloral patch

or mixed patch

Nectariferous Concealed

58 Proc Zool Soc (Jan-June 2012) 65(1):57–60

123

Fig. 1. The values of Shannon-Wiener Function and

Brillouin’s Index in case of cultivated food plants (viz.,

B. nigra = 3.1207, 2.2384; H. annuus = 2.9325, 2.5022

and C. maxima = 2.7741, 2.1413 respectively), are

higher compared to that of the wild plants (viz.,

L. camara = 2.4941, 1.8628; A. conyzoides = 2.5344,

1.8393; E. odoratum = 2.5666, 1.8164 and M. corda-

ta = 2.5163, 1.7615 respectively) and cultivated horticul-

tural plant species (viz., P. tuberosa = 2.4038, 1.8091; I.

coccinea = 2.3520, 1.7002 and T. patula = 2.4094,

1.7642 respectively) (Table 2; Fig. 1). The different spe-

cies of foraging hymenopterans on specific floral patches

have been shown in Table 3.

Discussion

Very few attempts have been made to measure the amount

of information transferred in animal communication sys-

tems (Hazlett and Bossert 1965). Haldane and Spurway

(1954) applied Shannon’s formula in order to decipher the

angular orientation of newcomer honeybees around a food

resource following waggle dance. The same was followed

by Wilson (1962). Though the information content among

individuals of the same species of animals had been mea-

sured yet no effort has been made to quantify the same

between community like plant species and animal species

dependent on them. The most frequently used measure of

species diversity is based on information theory like

Shannon-Wiener Function (Shannon and Weaver 1949)

and Brillouin’s Index (Krebs 1991). The information con-

tent is a measure of the amount of uncertainty (Margalef

1958) so that larger the value of Index, greater will be the

Table 3 Occurrence of hymenopteran species on ten floral patches

Hymenopteran species Floral patch

I II III IV V VI VII VIII IX X

Apis dorsata Fabr. ? ? ? ? ? ? ? ? ? ?

Apis mellifera Linnaeus ? ? ? ? ? ? ? ? ? ?

Apis cerana indica Fabr. ? ? ? ? ? ? ? ? ? ?

Apis florea Fabr. ? ? ? ? ? ? ? ? ? ?

Andrena ilerda Cameron ? – – – – – – – – –

Andrena leaena Cameron ? – – – – – – – – –

Anthophora zonata (Linn.) ? – – – – – – – – –

Xylocopa pubescensSpinola

? – ? – ? ? ? – – –

Xylocopa fenestrata(Fabr.)

– ? ? ? ? ? ? – – –

Osmia adae Bingh ? – – – – – – – – –

Trigona thoracica Smith – ? ? – – – – – – –

Bombus orientalis Smith ? ? ? ? ? ? ? – – –

Camponotus compressus(Fabricius)

? – – – – – – – – –

Megachile nana Bingh – ? – ? ? ? ? ? ? ?

Megachile femorata Smith – ? – – – ? ? ? ? ?

Tetraponera rufonigra(Jerdon)

? – – – – – – ? ? ?

I = Brassica nigra, II = Helianthus annuus, III = Cucurbita max-ima, IV = Lantana camara, V = Ageratum conyzoides, VI = Eup-atorium odoratum, VII = Mikania cordata, VIII = Polianthestuberosa, IX = Ixora coccinea, X = Tagetes patula, ? indicates the

presence and - indicates the absence of the species

0 1 2 3 4

Brassica nigra

Helianthusannuus

Cucurbitamaxima

Lantana camara

Ageratumconyzoides

Eupatoriumodoratum

Mikania cordata

Polianthestuberosa

Ixora coccinea

Tagetes patula SHANNON-WIENERFUNCTION

BRILLOUIN'S INDEX

Flo

ral P

atch

es

Information content (bits/patch)

Fig. 1 Floral patch-wise comparative scenario of Shannon-Wiener

function and Brillouin’s Index

Table 2 Summary of the species diversity indices (bits per patch) of

ten floral patches studied

Floral patches Brillouin’s

Index

(bits/patch)

Shannon-Wiener

function

(bits/patch)

Brassica nigra 2.2384 3.1207

Helianthus annuus 2.5022 2.9325

Cucurbita maxima 2.1413 2.7741

Lantana camara 1.8628 2.4941

Ageratum conyzoides 1.8393 2.5344

Eupatorium odoratum 1.8164 2.5666

Mikania cordata 1.7615 2.5163

Polianthes tuberosa 1.8091 2.4038

Ixora coccinea 1.7002 2.3520

Tagetes patula 1.7642 2.4094

Proc Zool Soc (Jan-June 2012) 65(1):57–60 59

123

uncertainty, in other words, it will indicate greater species

diversity. The uncertainty will be less with the reduced

numerical value of Shannon Index indicating less diversity

of species. A community with only one species, in it, has

no uncertainty, and thus species diversity index is zero.

This scenario can be interpreted in the present study of

insect-plant interaction with a view that floral patch (viz.,

L. camara, A. conyzoides, E. odoratum, M. cordata,

P. tuberosa, I. coccinea and T. patula) having less species

diversity of foraging insects has information entropy of

resource entertaining only a few species which can explore

them efficiently in comparison to others having specialized

biomechanical and morphological adaptive traits of

mouthparts. On the other hand, floral patch (viz., B. nigra,

H. annuus, C. maxima) having greater species diversity

means a generalized resource base, which can attract large

number of insect species with an easy access to its

resources in a generalized pattern as a whole (Kevan and

Baker 1983; Barth 1991; Abrol 2005). In the present study,

the collected samples are not random samples drawn from

a large community in which the total number of species is

known. Such community samples should be treated as

collections rather than as random samples (Pielou 1966). In

this context, Brillouin’s formula could be an appropriate

information-theoretic measure of diversity (Krebs 1991).

Hence, the most frequently used Shannon-Wiener Function

and Brillouin’s Index has been followed and compared. In

our study only the hymenopteran species, mostly depen-

dent on floral resources (viz., nectar, pollen grains etc.),

have been taken into consideration in order to avoid the

occasional visitors of flowers. Hence in this study, barring

from other signals of the floral patches the common

resources like nectar and pollen grains mostly used by the

hymenopterans have been considered as the principal sig-

nals from the floral patches (Table 1). In this study, the

greater information content as denoted by the higher values

of Shannon-Wiener Function in case of cultivated food

plants (viz., B. nigra, H. annuus, C. maxima) points

towards the greater exploitation of these plants by the

larger number of foraging insects. Similarly, the Brillouin’s

Index with higher values (i.e. more than 2 bits per patch)

only in case of these cultivated food plants corroborate the

same inference. On the contrary, lower values of infor-

mation content, as represented by the diversity indices of

Shannon-Wiener Function and Brillouin’s Index in case of

wild plants (viz., L. camara, A. conyzoides, E. odoratum

and M. cordata) and cultivated horticultural plants (viz.,

P. tuberosa, I. coccinea and T. patula) probably suggest a

lesser preference of these plant species by the visiting

hymenopterans. Probably, the rich nectar content of the

cultivated food plant species generates such high infor-

mation content having higher diversity of foraging hy-

menopterans as evident in the study. Such quantification

protocol may be useful in understanding the other aspects

of interactions between plant and animal communities as a

whole.

Acknowledgments The authors would like to express their grati-

tude to the Department of Botany, University of Calcutta and the

Department of Zoology, West Bengal State University, Barasat, for

their cooperation during the entire study period.

References

Abrol, D.P. 2005. Pollination energetics. Journal of Asia-PacificEntomology 8(1): 3–14.

Barth, F.G. 1991. Insects and flowers: The biology of partnership.

Princeton: Princeton University Press.

Gilbert, L.E., and P.H. Raven. 1975. Coevolution of animals andplants. Austin: University of Texas Press.

Haldane, J.B.S., and H. Spurway. 1954. A statistical analysis of

communication in Apis mellifera and a comparison with

communication in other animals. Insectes Sociaux 1(3): 247–

283.

Hazlett, B.A., and W.H. Bossert. 1965. A statistical analysis of the

aggressive communications systems of some hermit crabs.

Animal Behaviour 13(2, 3): 357–373.

Heinrich, B., and P.H. Raven. 1972. Energetics and pollination

ecology. Science 176: 597–602.

Kevan, P.G., and H.G. Baker. 1983. Insects as flower visitors and

pollinators. Annual Review of Entomology 28: 407–453.

Krebs, C.J. 1991. Ecological methodology, 2nd edition. New York:

Harper Collins.

Margalef, D.R. 1958. Information theory in ecology. General Systems3: 36–71.

Matthews, E.G., and R.L. Kitching. 1984. Insect ecology, 2nd ed. St.

Lucia: University of Queensland Press.

Pielou, E.C. 1966. The measurement of diversity in different types of

biological collections. Journal of Theoretical Biology 13:

131–144.

Price, P.W. 1984. Insect ecology, 2nd ed. New York: Wiley.

Shannon, C.E., and W. Weaver. 1949. The mathematical theory ofcommunication. Urbana: University of Illinois Press.

Strong, D.R., J.H. Lawton, and R. Southwood. 1984. Insects on plants:Community patterns and mechanisms. Oxford: Blackwell.

Wilson, E.O. 1962. Chemical communication among workers of the

fire ant Solenopsis saevissima (Fr. Smith):1, the organization of

mass-foraging; 2, an information analysis of the odour trail; 3,

the experimental induction of social responses. Animal Behav-iour 10(1, 2): 134–164.

60 Proc Zool Soc (Jan-June 2012) 65(1):57–60

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