WATER RELATIONS OF INSECTICIDE RESISTANT AND SUSCEPTIBLE GERMAN COCKROACHES (DICTYOPTERA, BLATTELLIDAE)

1. Percentage total body water content (%TBW), cuticular permeability (CP), and rate of water loss were determined for insecticide resistant and susceptible strains of the German cockroach, Blattella germanica (L.). 2. Initial body mass ranged from means of 95.52-122.72 mg, for f emale insecticide susceptible (ACY strain) and resistant (Maple) strai ns, respectively. Initial body mass of males ranged from means of 58.3 6 mg for a resistant strain (109) to 65.18 mg for a susceptible strain (Black). There were no differences in initial mass of nymphs among st rains. 3. Mean % total body water (%TBW) ranged from 68.21 to 71.95 fo r adult males, 66.78-71.89 for adult females and 70.56-71.61 for nymph s. ACY strain adults had greater %TBW than the other strains. There we re no differences in %TBW of nymphs among strains. 4. Mean cuticular p ermeabiity was not affected by initial mass for any stage or strain an d ranged from 11.34 to 32.69 mug/cm2/hr/mmHg for nymphal and male susc eptible strain (Black) B. germanica, respectively. 5. Cumulative mass and %TBW lost increased linearly with desiccation time. 6. Water relat ions of B. germanica are not related to levels of insecticide resistan ce.