Effect of photoperiod and temperature changes on the reproductive behavior of male Blattella germanica Linnaeus (Blattoidea: Blattellidae)

S. C. Pathak 1 & Rita Bhandari 2

1 Department of Post-graduate Studies and Research in Biological Sciences, Rani Durgavati University, JABALPUR (MP) 482001. INDIA, 2 Department of Zoology, Government Autonomous Science College, JABALPUR (MP) 482001. INDIA

Blattella germanica males were exposed to changes in photoperiod as well as temperature, before being paired with normal females of suitable age to study the effect, both separate as well as synergic, on their reproductive behavior, as shown by observational averages in terms of per cent time spent on such behavior. Comparison of these observational averages of control and experimental insects revealed that exposure to experimental conditions in nymphal instars had no effect on the sexual behavior of male adults. Adults maintained at low temperature (16 0 C + 2 0 C ) showed reproductive behavior only at normal (L/D cycle 14/10 h) or near normal Light / Dark cycles, but no such behavior at other L/D cycles. Insects kept at moderate temperature (25 0 C + 2 0 C) showed much higher observational averages at all L/D cycles except total darkness. Experimental adult males derived from culture maintained at high temperature (36 0 C + 2 0 C) showed no reproductive behavior in conditions of total darkness as well as total illumination, but the behavior was more or less unaffected at other L/D Cycles. Qualitative changes in the intensity of sexual behavior due to these experimental exposures were also noted. The effects were generally reversible although it took more time in insects maintained at low temperatures to revert to normal averages as compared to insects kept at higher temperatures.

Index terms: Photoperiod, Temperature, Sexual behavior, Observational averages.

---