Department of Zoology, B.N.Mandal University, Madhepura, Bihar, India
Received : 2nd December, 2019 ; Revised :30th January,2020
Abstract: Portfolio function is an investment term usually applied used in finance management but due to the unpredicted loss & gain of biodiversity, population biologist and environmentalist have started using this concept in biodiversity studies. When more diversity is added to any investment portfolio, less risk is involved, hence community rich in biodiversity is considered to be rich in bioresources with ample security & insurance in contrast to those having less diversity of species. The functional concept of community & ecosystem is almost equal to well organised portfolios of the nature (Frank Figge 2004).1 In the present research paper the author has ventured to apply the portfolio theory in the population diversity of Bihar hairy caterpillar, Spilosoma spp. randomly sampled from different agricultural & weedy plots of Saharsa. Eight species sampled from four zones of this area have collective species diversity index value (SW=H) of 0.7002 (Z-1), 0.7627 (Z-2), 0.7909 (Z-3) & 0.8564 (Z-4) calculated by applying standard statistical equation to the sampled population. The value reflects that zone-4 is richest in terms of Spilosoma spp population thriving on different host weeds & crops in this area but largely destroying the host asset (weeds & crops). The diversity value of the pest in zone-1 is poorest that also indicates the smart portfolio management of the nature with respect to the population of weeds & host crops. Crisscross interrelationship & implications of such diversity of the pest & host in the portfolio function of the hairy caterpillar has been discussed under the light of investment policies of nature in the communities.