Environmental factors affecting the quality and quantity of hemoglobin in Chironomus larvae (Diptera:Chironomidae)

Abstract

The total Hb content and the electrophoretically distinguishable components were compared among 10 species of Chironomus. The respiration rates and the survival rates under anoxia were also evaluated for all species. Although larvae used for experiments were all reared under the same laboratory condition, the Hb content and composition differed interspecifically, suggesting genetic control of Hb production in Chironomus. However, the phylogenetic relationship inferred from a cluster analysis of Hb components differed greatly from the phylogeny based on randomly amplified polymorphic DNA (RAPD) analysis. The phylogenetic congruence suggests that some convergent evolution occurs in Hb composition of some lentic Chironomus species. Among the three factors, respiration rate, total Hb content and Hb diversity, the survival duration under anoxia was significantly correlated with the Hb content and respiration rate. In the species inhabiting a lentic environment where the chironomids are frequently exposed to low oxygen conditions, high respiration rates and high survival rates may be achieved by possession of abundant and specific Hbs compared with the lotic species' Hb.