Impact of temperature and relative humidity on population abundance of predatory spiders in cotton fields.

An experiment on recording the predatory spiders from sprayed and unsprayed cotton grown at Agriculture Research Institute Tandojam was carried out during July-September 2008. The results revealed that seven species of predatory spiders were recorded from cotton and identified first time from Sindh. Lycosidae (513) and Thomisidae (210) families comprised of Lycosa tista, L. kempi, L. machenziei and Pardosa berminica and Thomisus projectus, T. bulani and Thomisus sp. Total capture in the months of July, august and September were 164 (24.94 +/- 2.24 degrees C, 78.86 +/- 4.40%R.H.), 444 (22.5 +/- 1.28 degrees C, 79.33 +/- 4.40%R.H.) and 98 (22.93 +/- 2.30 degrees C, 72.16 +/- 2.30%R.H.) respectively. From un-sprayed venue maximum predatory spiders plant(-1) were P. birminica (6.65 +/- 0.51) followed by Thomisus sp (4.23) and L. tista (2.42 +/- 0.31). Similarly from sprayed fields were P. berminica (3.12 +/- 0.35) followed by Thomisus sp (2.35 +/- 0.30) and L. tista (1.46 +/- 0.20). In the month of July spiders plant-1 were 2.94 +/- 0.22 when temperature and R. H. were 24.94 degrees C and 78.6% respectively. Similarly in the month of August and September were 2.86 +/- 0.180 (22.5 +/- 1.28 degrees C, 79.33 +/- 4.40% R.H.) (r = 0.670**) and 1.45=0.34 (22.93 +/- 2.30 degrees C, 72.16 +/- 2.30% R.H.) (r = 0.477**).