RELATION BETWEEN BIOMASS AND DIVERSITY OF INSECTS: A STUDY USING LIGHT TRAPPED INSECTS

A study was conducted to explore the seasonal variation in the abundance and diversity of insects attracted to light trap, and the relationship between biomass and diversity of insect. The study was conducted at GKVK campus, Bengaluru for twelve months (May, 2015 to April, 2016) at an interval of 21 days. A total of 16 samples throughout the year yielded 65,469 insects belonging to 639 OTUs. Species richness peaked during early rains (May-June) and during post monsoon (August-September). Abundance as well as total weight of insects sampled were high during May-June corresponding to early rains in Bengaluru. Body size parameters viz., body length, width and size revealed a positively skewed frequency distribution whereas, body dry weight showed a normal distribution. Inter-relationship among these body size parameters were best explained by power functions. Temporal patterns of body size and body dry weight revealed a high abundance of small insects during monsoon and post monsoon and of large insects during winter and summer (November to June). Rainfall received on or before the sampling significantly reduced the insects trapped and their diversity. However, time lag correlation studies revealed that rainfall received in a three day window before 7 and 8 day of sampling had a positive impact on the diversity and abundance of insects. Temporal variation in ecosystem productivity indicated two peaks viz., during pre-monsoon and post-monsoon period; diversity and abundance were found to be negatively correlated with ecosystem productivity. August, 2016 Department of forestry and Environmental Science K. N. Ganeshaiah UAS, GKVK, Bangalore (Major Advisor) ¢Ã¥À§ ̄ÉAiÀÄ°è ̧ÀAUÀæ»vÀaÁzÀ QÃlUÀ1⁄4À aÀÄÆ®PÀ, CaÀÅUÀ1⁄4À fÃaÀgÁ2 aÀÄvÀÄÛ aÉÊ«zsÀåvÉAiÀÄ £ÀqÀÄ«£À ̧ÀA§AzsÀzÀ PÀÄjvÀÄ CzsÀåAiÀÄ£À ¥Àæ s̈ÀAzsÀzÀ ̧ÁgÁA±À IÄvÀÄaÀiÁ£ÀzÀ §zÀ̄ ÁaÀuÉUÉ C£ÀÄ ̧ÁgÀaÁV QÃlUÀ1⁄4À oÉÃgÀ1⁄4ÀvÉ, aÀÄvÀÄÛ aÉÊ«zs ÀåvÉAiÀÄ°è PÁt§oÀÄzÁzÀ ¥ÀæPÁgÀ oÁUÀÆ, CaÀÅUÀ1⁄4À £ÀqÀÄ«£À À̧A§AzsÀzÀ PÀÄjvÀÄ MAzÀÄ aÀμÀðzÀ PÁ ̄ÁaÀ¢AiÀÄ°è ¥ÁæAiÉÆÃVPÀ CzÀåAiÀÄ£ÀaÀ£ÀÄß PÉÊUÉÆ1⁄4Àî ̄Á¬ÄvÀÄ. 21 ¢£ÀUÀ1⁄4À CAvÀgÀzÀ°è aÀμÀð«rÃ (aÉÄÃ, 2015 jAzÀ K¦æ ̄ï 2016 aÀgÉUÉ) aÀåaÀ̧ ÉÛUÉÆ1⁄2 À̧̄ ÁzÀ ¢Ã¥À§ É̄UÀ1⁄4À°è ̧ÀAUÀæoÀaÁzÀ QÃlUÀ1⁄4À MlÄÖ ̧ÀASÉå ̧ÀÄaÀiÁgÀÄ 65,469. EaÀÅ 639 ¥Àæ É̈ÃzsÀUÀ1⁄2UÉ Ȩ́ÃgÀzÀÄÝ, ¥ÀÆaÀð-aÀÄÄAUÁgÀÄ (aÉÄÃ-dÆ£ï) oÁUÀÆ »AUÁj£À (DUÀ̧ ïÖ̧É¥ÉÖA§gï) ¢£ÀUÀ1⁄4À°è CvÀå¢üPÀ ¥Àæ É̈ÃzsÀUÀ1⁄4ÀÄ À̧AUÀæoÀUÀaÁVzÀÝaÀÅ. QÃlUÀ1⁄4À ̧ÀASÉå aÀÄvÀÄÛ MlÄÖ vÀÆPÀaÀÇ PÀÆqÁ ¥ÀÆaÀð-aÀÄÄAUÁj£À ¢£ÀUÀ1⁄4À°è C¢üPÀaÁVzÀÝaÉAzÀÄ PÀAqÀÄ§A¢vÀÄ. ¥Àæ ̈sÉÃzÀUÀ1⁄4À zÉÃoÀ gÀZÀ£ÉAiÀÄ aÀiÁ¥ÀPÀUÀ1⁄4ÁzÀ GzÀÝ, CUÀ®, MlÄÖ UÁvÀæ aÀÄvÀÄÛ vÀÆPÀUÀ1⁄4À ̧ÁATåÃPÀ «vÀgÀuÉAiÀÄ ̧ÀégÀÆ¥À oÁUÀÆ CaÀÅUÀ1⁄4À £ÀqÀÄ«£À À̧A§AzsÀUÀ1⁄4À §UÉÎ CzsÀåAiÀÄ£ÀaÀ£ÀÄß £ÀqȨ́ À̄ Á¬ÄvÀÄ. CAvÉAiÉÄÃ IÄvÀÄUÀ1⁄2UÀ£ÀÄUÀÄtaÁV DPÀ¶ðvÀUÉÆAqÀ QÃlUÀ1⁄4À UÁvÀæzÀ°è EgÀ§oÀÄzÁzÀ aÀåvÁå ̧ÀUÀ1⁄4À£ÀÄß UÀaÀÄ¤ À̧̄ Á¬ÄvÀÄ. aÀÄ1⁄4ÉUÁ®zÀ°è ̧ÀtÚ QÃlUÀ1⁄4ÀÄ C¢üPÀ̧ ÀASÉåAiÀÄ°èzÀÝgÉ zÉÆqÀØ QÃlUÀ1⁄4ÀÄ »AUÁj£À À̧aÀÄAiÀÄzÀ°è C¢üPÀaÁVzÀÝaÀÅ. aÀÄ1⁄4É oÁUÀÆ QÃlUÀ1⁄4À ZÀlÄaÀnPÉAiÀÄ £ÀqÀÄ«£À ̧ÀA§AzsÀaÀ£ÀÄßCaÀ̄ ÉÆÃQ1zÁUÀ aÀÄ1⁄4ÉAiÀiÁzÀ K1⁄4ÉAlÄÖ ¢£ÀUÀ1⁄4À £ÀAvÀgÀ QÃlUÀ1⁄4À ̧ÀASÉå aÀÄvÀÄÛ aÉÊ«zÀåvÉ oÉZÁÑUÀÄvÀÛzÉ JAzÀÄ w1⁄2zÀÄ§A¢zÉ. DUÀ̧ ïÖ-2016 PÉ. J£ï. UÀuÉÃ±ÀAiÀÄå (¥ÀæzsÁ£À aÀiÁUÀðzÀ±ÀðPÀgÀÄ) CgÀtå aÀÄvÀÄÛ ¥Àj ̧ÀgÀ CzsÁå£À « s̈ÁUÀ UÁA¢ü PÀÈ¶ «eÁÕ£À PÉÃAzÀæ, ̈ÉAUÀ1⁄4ÀÆgÀÄ-560065