Abstract:

In 20℃, respiratory signals of four species of cockroaches including Periplaneta americana, P. brunnea, P. australasiae, Blattella germanica were sampled and analyzed with infrared CO₂ analyzer. The results indicated that they all  exhibited the respiratory model of discontinuous gas exchange cycle (DGC). A DGC was divided into two periods，including an interburst period and a burst period. There were some differences among DGC characters of different species. A DGC period of P. americanawas about 24.55 min, obviously longer than that of P. brunnea (11.67 min) and P. australasiae (10.75 min), and it was only 4.41 min for B. germanica. The proportion of interburst period duration to DGC duration in P. americana was the highest with the mean value 57%, which was 48%, 37% and 36% for B. germanica, P. brunnea and P. australasiae respectively. The CO₂ release rate per body weight in B. germanica was the highest, and there was no obvious difference among the rest three species. The CO₂ release volume of burst period increased with the increase of DGC duration in the four species. The CO₂ release rate per body weight decreased with the increase of DGC duration in P. americana and B. germanica, but their correlations were not obvious in P. brunnea and P. australasiae. The CO₂ release rate and CO₂ release volume of burst period had positive correlation with body weight in other three species except B. germanica. Body weight did not influence the durations of DGC, interburst period and burst period and the DGC frequency in all four species.

Key words: Cockroaches, respiratory signal, discontinuous gas exchange cycle, characteristic analysis