MONITORING HYMENOPTERA AND DIPTERA POLLINATORS IN A SUB-TROPICAL FOREST OF SOUTHERN PUNJAB, PAKISTAN

Bees (Hymenoptera) and flies (Diptera) play an essential role in natural and agricultural ecosystems as pollinators of flowering plants while pollinators are declining around the world. Colored pan traps and Malaise traps have widely been used for monitoring pollinators. However, their efficiencies may vary with landscapes and type of fauna in a particular habitat. A yearlong study was carried out during 2009 to investigate the relative efficacy of colored pan traps and Malaise traps towards sampling flies and bees for the first time in a sub-tropical wildlife sanctuary ‘Pirowal’ of Southern Punjab, Pakistan. Fifteen pan traps (5 each of 3 colors i.e. white, red and blue) were deployed against one Malaise trap for 7 hours (9:00-16:00 hrs) on fortnightly basis. For the comparison and confirmation of an insect as a floral visitor, collection with the hand net was also performed. It was concluded that hand net collection is essential to have a comprehensive list of floral visitors of an area as the maximum number (63) of species and their abundance (5428 individuals) were recorded with it. Malaise trap collected only 671 individuals of 48 species. Although blue, yellow and white pan traps caught 46, 51 and 35 species but the numbers of individuals (1383) were fairly higher than that of Malaise traps. Keeping in view the cost effectiveness and better performance of colored pan traps, we recommend species specific pan trap colors when targeting certain groups or species, nevertheless variety of pan colors should be used when sampling overall biodiversity. We generalize these findings for both bees and flies due to similar collection pattern i.e. the maximum abundance and diversity in hand net method followed by pan traps and Malaise traps.