Aquatic Insects Chironomidae

The relationships between physical properties, water chemistry and aquatic macroinvertebrates were investigated in riffles of four perennial streams in the arid northern Oman. Samples were collected monthly in autumn, winter and spring with a Surber net. Thirty two
invertebrate taxa were recorded, most species are widely distributed,
but few species with very restricted distribution were also captured.
Diptera followed by Pulmonata, Coleoptera and Odonata were the most represented taxa, Trichoptera and Heteroptera were a significant component only in one station (the Fezeh), where the lowest mean water temperature (23°C) was recorded. In the dry months from May to October, aquatic macroinvertebrates were completely absent. In order
to summarize the community response some biotic indices were calculated.
The highest diversity was observed in the Fezeh station. A
seasonal gradient was also observed, with the highest diversity values
in January, April, and December. The low faunal diversity was attributed to the high air and water temperature and the hydrological regime instability. A between station and a between month coinertia analysis was carried out, to analyze the response to spatial and seasonal
factors. The first coinertia axis was correlated with altitude and substrate composition, while the second axis was correlated with air and water temperature.
The present research emphasizes the urgency for preserving the
less disturbed wadis in arid zones, because, despite their species poorness, their uniqueness in faunal composition requires special attention.
The presence of few endemic species with very restricted distribution
highlights the topicality and the value in investigating these
areas, allowing the increase of our knowledge on biodiversity, ecology and biogeography about the benthic macroinvertebrates living in these extreme habitats.

As one group of Chironomidae Tanypodinae larvae can be used in biological assessment to detect the heavy metal pollution in aquatic environment, because they could show morphological changes due to the pollution. The study was aimed to describe ligula deformities in Tanypodinae larvae in a heavy metal polluted lake. The study was conducted in Mei to June 2014 at Lake Lido, West Java. The results showed that lead (Pb) concentration in Lido Lake was quaite high, i.e. 0.08 0.19 mg/L. Ten of fifty-five collected Tanypodinae larve exhibited deformation in their ligulae. Index of severity of ligula deformation (ILSD) was 4.4 indicating the response of the Chironomidae larvae to lead pollution.