| Title | The relationship between body size, pupal thoracic horn development and dissolved oxygen in Chironomini (Diptera : Chironomidae) |
| Abstract | The aim of this study was to analyze the relationship between the surface development of pupal thoracic horn and adaptation to low oxygen concentration in different species of chironomids. A total of 773 samples of larvae were collected in lakes and streams together with measurements of dissolved oxygen and collection of pupal exuviae. The area of the base of the thoracic horn (ring organ, RO) and abdomen length (ABD) of pupae were measured in forty-eight species of Chironomini. RO was significantly correlated with ABD, therefore, the ratio of ring organ/abdomen length (ROA) was calculated to provide a measure less dependent on body size. Chironomus plumosus Linnwus, Chironomus riparius Meigen and Glyptotendipes pallens (Meigen) had the highest ROA, Microtendipes britteni (Edwards), Paralauterbomiella nigrohalteralis (Malloch) and Pseudochironomus prasinatus (Stxger) had the lowest ROA. ROA was still correlated with ABD, so residuals from the regression line (RROA) between RO and ABD were also calculated. An examination of the residuals revealed that some species (C riparius, Cladopelma virescens (Meigen) and Einfeldia pagana (Meigen)) had a RO larger, whereas other species (M. britteni, P. prasinatus and Stenochironomus gibbus (Fabricius)) had a RO smaller than predicted by regression with ABD. RO was significantly correlated with the 25(th) percentile of dissolved oxygen (PCTL) measured in conjunction with benthic macroinvertebrates samples. Hemoglobin concentrations measured in six species were not correlated with ABD and RO, a high hemoglobin content was measured both in small species with a small RO (Polypedilum nubeculosum (Meigen)) and in large species with a large RO (G. pallens). The ring organ is proposed as a morphological trait useful to indicate oxygen concentration in the environment, while other factors such as hemoglobin content are also likely to affect the species ability to respond to oxygen shortage. |
| Source | Fundamental and applied limnology 169 (4), pp. 331–339 |
| Keywords | chironomidaethoracic hornbody sizeoxygenhemoglobin |
| Journal | Fundamental and applied limnology |
| Editor | Schweizerbart, Stuttgart, Germania |
| Year | 2007 |
| Type | Articolo in rivista |
| DOI | 10.1127/1863-9135/2007/0169-0331 |
| Authors | Rossaro, Bruno; Solimini, Angelo; Lencioni, Valeria; Marziali, Laura; Giacchini, Roberto; Parenti, Paolo |
| Text | 309648 2007 10.1127/1863 9135/2007/0169 0331 ISI Web of Science WOS 000250219400006 chironomidae thoracic horn body size oxygen hemoglobin The relationship between body size, pupal thoracic horn development and dissolved oxygen in Chironomini Diptera Chironomidae Rossaro, Bruno; Solimini, Angelo; Lencioni, Valeria; Marziali, Laura; Giacchini, Roberto; Parenti, Paolo University of Milan; Commiss European Communities; Museo Tridentino Sci Nat; University of Milano Bicocca The aim of this study was to analyze the relationship between the surface development of pupal thoracic horn and adaptation to low oxygen concentration in different species of chironomids. A total of 773 samples of larvae were collected in lakes and streams together with measurements of dissolved oxygen and collection of pupal exuviae. The area of the base of the thoracic horn ring organ, RO and abdomen length ABD of pupae were measured in forty eight species of Chironomini. RO was significantly correlated with ABD, therefore, the ratio of ring organ/abdomen length ROA was calculated to provide a measure less dependent on body size. Chironomus plumosus Linnwus, Chironomus riparius Meigen and Glyptotendipes pallens Meigen had the highest ROA, Microtendipes britteni Edwards , Paralauterbomiella nigrohalteralis Malloch and Pseudochironomus prasinatus Stxger had the lowest ROA. ROA was still correlated with ABD, so residuals from the regression line RROA between RO and ABD were also calculated. An examination of the residuals revealed that some species C riparius, Cladopelma virescens Meigen and Einfeldia pagana Meigen had a RO larger, whereas other species M. britteni, P. prasinatus and Stenochironomus gibbus Fabricius had a RO smaller than predicted by regression with ABD. RO was significantly correlated with the 25 th percentile of dissolved oxygen PCTL measured in conjunction with benthic macroinvertebrates samples. Hemoglobin concentrations measured in six species were not correlated with ABD and RO, a high hemoglobin content was measured both in small species with a small RO Polypedilum nubeculosum Meigen and in large species with a large RO G. pallens . The ring organ is proposed as a morphological trait useful to indicate oxygen concentration in the environment, while other factors such as hemoglobin content are also likely to affect the species ability to respond to oxygen shortage. 169 Articolo in rivista Schweizerbart 1863 9135 Fundamental and applied limnology Fundamental and applied limnology Fundam. appl. limnol. Fundamental and applied limnology. Archiv fur Hydrobiologie 2007 laura.marziali MARZIALI LAURA |
