The water-vapour uptake system of the phthiraptera
1983; Elsevier BV; Volume: 29; Issue: 1 Linguagem: Inglês
10.1016/0022-1910(83)90101-4
ISSN1879-1611
Autores Tópico(s)Insect-Plant Interactions and Control
ResumoThe occurrence of active water-vapour uptake was examined in 16 Phthirapteran species representing the two groups of biting lice or Mallophaga (Amblycera and Ischnocera) and the sucking lice or Anoplura. Water-vapour uptake could not be demonstrated in the Anoplura and although it is frequently encountered in the biting lice, some members of both the Ischnocera and Amblycera lack the faculty. Uptake performance in the absorbing species of biting lice is exceptionally efficient showing higher rates and lower thresholds than other absorbing arthropods. The critical equilibrium humidities were found to range between 43 and 52% r.h., 43% being the lowest value so far reported. The uptake rates, expressed as a percentage of total body water mass, by far surpass those of all other arthropods investigated. The Phthirapteran uptake pattern closely resembles that of the Psocoptera, showing abrupt initiation and termination of the uptake process, limitation of continuous absorption to relatively short periods of time and constancy of the absorption rate over the entire period of continuous uptake. Studies on the uptake site and mechanism in Phthiraptera revealed an oral-uptake system which is congruous with that of the Psocoptera. The structural components of the uptake device, like a pair of oval lingual sclerites, representing the site of water-vapour condensation and a cibarial sucking pump which is connected by a paired or branching selerotized tubule to the lingual selerites and is responsible for the transfer of the condensed water to the gut, are unique acquisitions of the Psocodea. In those members of the biting lice which have lost the faculty of water-vapour uptake the structural components of the uptake system are modified or reduced.
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