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Divergent mechanisms for water conservation in D rosophila species
Author(s) -
Kalra Bhawna,
Parkash Ravi,
Aggarwal Dau Dayal
Publication year - 2014
Publication title -
entomologia experimentalis et applicata
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.765
H-Index - 83
eISSN - 1570-7458
pISSN - 0013-8703
DOI - 10.1111/eea.12169
Subject(s) - biology , desiccation , botany , interspecific competition , acclimatization , zoology
The role of melanization and cuticular lipids in water conservation has been studied in many D rosophila species ( D iptera: D rosophilidae). Nevertheless, a comparative approach to larval and adult stages of ecologically diverse, wild D rosophila species is still required. Based upon abdominal cuticular melanization patterns, wild‐caught D rosophila species were categorized as (1) melanic, (2) fixed‐melanic, or (3) non‐melanic. At the interspecific level, the ecological significance of melanization and cuticular lipids was determined by the inverse association of melanization and cuticular water loss in melanic species, and of cuticular lipids and cuticular water loss in fixed‐melanic and non‐melanic species. Interestingly, higher amounts of cuticular lipids were also evident in fixed as well as non‐melanic species, as compared to melanic species at larval stages, which is consistent with their differences in reduced water loss rates. Moreover, fixed‐melanic and non‐melanic species exhibited comparatively higher (ca. 1.8–2.0 fold) desiccation resistance. Thus, cuticular lipids provide a better waterproofing mechanism than melanization. Furthermore, acclimation to dehydration stress in adults improved desiccation resistance in melanic species, whereas such effects were lacking in fixed‐melanic and non‐melanic species. However, there were no changes in cuticular components as a consequence of desiccation acclimation. Thus, our results indicate that melanic, fixed‐melanic, and non‐melanic D rosophila species differ in the evolved physiological mechanisms of water conservation to adapt to dry conditions.