SOME BIOLOGICAL AND PHYSICAL DETERMINANTS OF PIT SIZE IN LARVAE OF MYRMELEON PICTIFRONS GERSTAECKER (NEUROPTERA: MYRMELEONTIDAE)

Within each larval instar of the ant lion, Myrmeleon pictifrons there is a linear, increasing relationship between larval size and pit size. Across instars mean pit diameter increases non‐linearly. Three larval instars may be distinguished readily on their body length. No pits are built in sand of moisture content greater than 4% and there is a substantial decline in pit size at moisture contents over 1.5%. The relationship between pit size and temperature is sigmoid, increasing from lower to higher temperatures. No pits are built in substrates of grain size greater than 1 mm and only small pits at grain size below 0.125 mm. In grain sizes between 0.125 and 1.0 mm pits of normal mean size are constructed although these figures have large associated variances. The results obtained are compared and contrasted with those of authors studying other species of pit‐building ant lions.