Species Of Chironomid Larvae Research Articles

Taxonomic structure of the zoobenthos of the Lukoml GRES cooling reservoir

The species composition of zoobenthos in the heated and non-heated zones of the cooling lake Lukoml State District Power Station was studied. 80 taxa of bottom animals have been registered, and two new species of chironomid larvae have been identified. The bottom fauna includes a protected relict species of Pallaseopsis qudrispinosa, which is preserved in the conditions of warming.it is listed in the Red book of Belarus and the alien species – freshwater shrimp Macrobrachium nipponense. The high taxonomic diversity indicates that the Lukoml State District Power Station operation has little impact on the bottom community throughout the lake’s water area. However, species richness is reduced locally by half in the zone of influence of heated water discharge, especially in summer. Under the influence of heating, the taxonomic structure and spatial distribution at different depths change.

A29 Chironomus 属ユスリカ幼虫数種の呼吸生理学的特性の相違について

A29 Chironomus 属ユスリカ幼虫数種の呼吸生理学的特性の相違について

The parabolic pattern of animal growth: determination of equation parameters and their temperature dependencies

SUMMARY1. Parabolic (power) growth is characteristic of many aquatic poikilothermic animals for certain stages of their development. The parabolic pattern describing growth in weight (or length) under constant ambient conditions can be expressed in the following general form: image where Y is growth rate (or specific growth rate), X is animal size, and Ω and τ are coefficients. The constancy of ambient conditions is of cardinal importance in determining τ. The problem of maintaining a constant level of nutrition can be reliably solved only by the presence of food in excess of demand. Data satisfying these requirements have demonstrated that τ does not depend on factors such as temperature, and can be assumed to be independent of ambient conditions. In the growth rate‐weight equation, τ ranges between 0.5 and 0.85 for animals representing a variety of taxonomic groups.2. The coefficient Ω. is affected by ambient conditions (e. g. temperature, amount of food). Its value reflects the ‘level’ of the growth rate‐size relationship under given conditions. For a specific time period, Ω can be computed from the following formula: image where X1 and X2 are the animal sizes (weights, lengths) at time t1 and t2, the beginning and end of the time period. The calculated value of Ω corresponds to the average intensity of the ambient factor (F) affecting the growth during the period between the two observations. If the values of the Ω are calculated for wide range of the factor, the relationship between the Ω. and F, Ω=f(F), can be determined. The function can be then incorporated into the parabolic equation of growth, as image 3. Dependence of the development rate (1/D, where D is time interval needed to complete a given stage) on temperature (T), and dependence of Ω on T, are both described by sigmoid‐shape curves. The broad intermediate part of these curves, a range to which animals are adapted in nature, can be approximated by straight line functions. For two groups, pan‐size sockeye salmon (Oncorhynchus nerka) and different species of chironomid larvae, it was shown that an equation combining parabolic growth and linear temperature patterns describes accurately the variability observed in growth rates under experimental and natural conditions.

A comparative study on mouthpart morphology of certain larvae of Chironomini (Diptera: Chironomidae) with reference to the larval feeding habits

Mouthparts of six species of chironomid larvae were compared on both an intra‐ and inter‐specific level. The species were: Chironomus riparius, Cryptochironomus defectus gr., Endochironomus albipennis, Glyptotendipes pallens, Microtendipes pedellus and Parachironomus arcuatus. The mouthpart morphology in C. defectus gr. and P. arcuatus is considerably different from the four other species and changes little between instars. Within C. riparius, E. albipennis, G. pallens and M. pedellus there is a considerable difference in the mouthpart morphology between the first instar and the remaining instars. The morphology of the mouthparts of the first instar of C. riparius, E. albipennis, G. pallens and M. pedellus resembles in many ways that found in C. defectus gr. and P. arcuatus.

Effect of preservation on wet weight biomass of chironomid larvae

Preservation of four species of chironomid larvae in either 10% formalin or 70% ethanol caused changes in the preserved wet weight expressed as a percentage of the original live wet weight. The magnitude of the change varied with species, preservative, preservation time and the nature of the water used for preservative dilution. Failure to take these factors into account can lead to errors in wet weight measurements as great as 47%. The use of io% formalin prepared with filtered habitat water appears to be the most suitable preservative for chironomid larvae.

Two Coelomomyces infections of Chironomidae (Diptera) larvae in Marion Lake, British Columbia.

Four species of chironomid larvae, Tanytarsus sp. A, Tanytarsus sp. B, Tanytarsini sp. A, and Psectrocladius sp. G from Marion Lake, British Columbia, are recorded as hosts of either Coelomomyces beirnei n.sp. or Coelomomyces chironomi var. canadense n. var. They are the first record of Coelomomyces infections of chironomid larvae outside Europe and represent only the third record of such hosts thus far known.