Chironomidae Larvae Research Articles

Growth and Development of Larval Chironomidae

Development rates, length-age growth rates and length-weight relationships were measured for twelve species of larval chironomid from the River Thames, UK. at 10, 15 and 20'C. From these data weight-age growth rates were calculated. The relationship between the weight (W) of a larva and its length (L) was described as a power function: W = aLb. The exponent b was found to depend on the size of the larva at maturation. The type of food fed to the larva of Ablabesmyia monilis L. greatly effected growth and development rates. Larvae of Cricotopus bicinctus (Meig.) responded to an increase of temperature from 15 to 20'C by an increase in development rate but not of growth rate, whilst the other species studied responded by an increase in both.

Species Diversity of Some Larval Chironomidae (Diptera) Communities in Two Rivers

Species diversity and equitability were measured using the Information Statistic and the Hill's Ratio. Six larval chironomid communities in two rivers were investigated. These communities were found to undergo a seasonal variation with high equitability and diversity in winter and low diversity and equitability in summer. Low equitability was due to high dominance caused by abundance of two Cricotopus species. The species-abundance relationship was suggested to be under the control of water temperatures. High larval production was associated with low diversity and high dominance. Continuous recruitment was seen as a strategy for reducing intraspecific competition whilst maintaining high populations. The role of predation in controlling diversity was explored.

A trap for capturing planktonic chironomid larvae

SummaryThis paper describes the construction and field operation of a trap designed to investigate the movements of larval Chironomidae in the open water of lakes. Although the trap was designed to be multidirectional, with six trapping bottles, only two directional components, vertical and horizontal, could be distinguished. This led to examination of three bottles only during later field studies, namely bottle 1 facing into the current, bottle 5 facing the substrate and bottle 6 facing the surface of the lake. Some results are presented and trap operation and sampling efficiency discussed.A major advantage of the trap is its use as a long term accumulator of planktonic organisms as opposed to traditional spot sampling techniques which tend to miss the less numerous plankters.

The food of the New Zealand common river galaxias, Galaxias vulgaris Stokell (Pisces: Salmoniformes)

The food of the common river galaxias, Galaxias vulgaris Stokell, inhabiting the Glentui River, Canterbury, New Zealand, was studied between June 1970 and November 1971. Basic food consisted of Ephemeroptera: particularly the larvae of Deleatidium spp., Coloburiscus humeralis and Nesameletus ornatus. Secondary food consisted of Elmidae (Coleoptera), terrestrial arthropods, and the larvae of Rhyacophilidae, Hydropsyche colonica, Olinga feredayi, Pycnocentrodes aureola (Trichoptera), Archichauliodes diversus (Megaloptera), Chironomidae and Simuliidae (Diptera). Other food items were considered to be incidental. Diet varied seasonally and with size of fish. Large fish tended to eat larger food items than small fish, and there was also an increase in variety of food items with increase in fish size. Recently hatched fish fed predominantly on dipteran larvae, changing to a mainly ephemeropteran diet on moving to the adult habitat. Diet did not change significantly with age in fish sampled in the same type of habitat. Male and female diets were very similar.

Life History of the Taillight Shiner, Notropis maculatus, in Central Florida

Spawning of the taillight shiner in central Florida occurred from March to early October at water temperatures of 23-32 C; major periods of activity occurred in early spring, late spring and late summer. Fecundity of gravid females ranged from 72-408 ova per female and was positively correlated with total length. Fertilized eggs, held at 23 C in laboratory aquaria, were demersal and adhesive and hatched within 60-72 hours. Larval taillight shiners were pelagic. Growth and maturation of taillight shiners were rapid but varied depending upon time of hatching. The spring (1970) group of young-of-the-year reached 40.2 mm in total length by August, was reproductively mature, and subsequently spawned; the early summer group was approximately 39 mm by October but did not mature until the following April; and the late summer group grew throughout the winter but did not reach 40 mm or reproductive maturity until April. Post-spawning mortality of 1-yearold fish occurred over a 2or 3-month period following the second spawning. Food consisted of algae, rotifers, copepods, cladocerans, ostracods and insects. However, utilization of food items varied with fish size. Larval shiners fed on rotifers, fish 20-40 mm long fed primarily on the cladoceran, Alonella globulosa, and larger fish (> 40 mm) fed predominantly upon insect larvae. Electivity indices indicated that all sizes of taillight shiners were highly selective for large algal cells. Copepods were rejected by fish smaller than 40 mm, but selection increased in larger sizes. The cladoceran, A. globulosa, was consumed in about the same proportions as available, and Chironomidae and Heleidae larvae apparently were positively selected by larger fish. INTRODUCTION The taillight shiner, Notropis maculatus (Hay), is found below the Fall Line from the Waccamaw drainage in North Carolina S to Florida, W to tributaries of the Red River in Oklahoma and N to southeastern Missouri. In Florida, it is found S in the peninsula to just below Lake Okeechobee (C. R. Gilbert, pers. comm.). The species occurs predominantly in lakes and ponds, but also is found in backwaters or sluggish pools in rivers (McLane, 1955; Pflieger, 1971). There is a lack of life history data on this species and other cyprinids of the southeastern-United States. In Florida, Bailey et at. (1954), McLane (1955), Hellier (1966), Barnett (1972) and Gilbert and Bailey (1972) have made brief observations on the ecology of the genus Notropis, and Marshall (1946) presented some life history data on N. chalybaeus (Cope). However, studies involving age determination and growth rates are lacking. We selected N. maculatus for study because its distribution approaches the southernmost extreme of the genus, and because it occurs 1 Present address: Florida Game and Freshwater Fish Commission, Vero Beach 32960.

The Production of Larval Chironomidae in the Mud at Loch Leven, Kinross

SynopsisThe production of four dominant species of larval Chironomidae (Chironomus anthracinus, Glyptotendipes paripes, Polypedilum nubeculosum and Limnochironomus pulsus) was measured and compared between different sections of the mud zone covering a total area of 662 ha (50 per cent of the loch bed) from March 1971 to March 1972. The results showed that the performance of Chironomus was very similar throughout the area in respect to numbers, growth and production but it was more variable in other species. The mean annual dry weight production of Chironomus over the whole area was 26 g/m2 and the four species together raised this to 29 g/m2 (equivalent to 579 k J/m2). The numbers of Chironomus increased and Glyptotendipes decreased through the sampling period. Estimates of biomass are given for other larval Chironomidae present in the mud. The accuracy of the results is discussed, as well as the variations in the seasonal growth of larvae and the changing composition of the community; some tentative estimates are given of assimilation by larval Chironomidae. The methods used for analysing these data are described in an appendix.

Food and growth of arctic char, Salvelinus alpinus (L.), in the Cumberland Sound area of Baffin Island

Arctic char, Salvelinus alpinus (L.), captured during the summer, 1972, in Cumberland Sound, Baffin Island, fed mainly on planktonic amphipods (Parathemisto libellula, Pseudalibrotus glacialis), copepods (Calanus hyperboreus), and fish (Boreogadus saida, Myoxocephalus sp.), but failed to utilize coelenterates, planktonic gastropods, and epi‐ and infauna. The considerable variation in the species composition of the diet of char of different lengths was due primarily to size selection. The average length of all individuals in stomach contents and of representatives of most food species increased with the length of fish. The minimum and maximum length of frequently ingested organisms increased four and 90 times, respectively, as char increased from 4 to 85 cm. Char less than 10 cm in length captured in rivers tributary to the Sound fed mainly on larval Chironomidae (Eukiefferiella bavaria) during the summer, whereas those longer than 10 cm fed predominantly on other char. During the winter the stomachs of the smaller individuals were always empty while the diet of the large char was restricted to other fish. Most species available to the char were consumed in proportion to their relative abundance in the rivers. The dry weight of stomach contents, when expressed on a unit weight basis, decreased with the wet weight of char in both fresh and salt water. Thus, fish 10 g in weight contained approximately 1.5 times more food in their stomachs than those weighing 1000 g. The stomach contents of char captured in salt water weighed approximately 11 times more than those of char of comparable size captured simultaneously in fresh water. The fish fed at random intervals during the day and ceased feeding at night. Arctic char, at all sampling areas, had reached a length of approximately 9.6 cm after four years. Upon migrating to salt water, their growth rate increased sharply with the result that after eight years they were 26.5 cm in length, reflecting food availability. The growth rate gradually decreased in fish older than nine years so that 20 year olds were approximately 70.0 cm in length.

The Zoobenthos of Loch Leven, Kinross, and Estimates of its Production in the Sandy Littoral Area during 1970 and 1971

SynopsisThe available information, both published and unpublished, on the zoobenthos of Loch Leven has been studied and tabulated. There have been a number of major changes in the community over the last 100 years—notably a reduction in diversity of the fauna with the disappearance of many species of invertebrates, particularly Ephemeroptera, Odonata and Coleoptera. The existing macro-invertebrate fauna is dominated by larval Chironomidae, but Nematoda, Mollusca, Annelida and Crustacea are also of importance. Dramatic changes have taken place in the chironomid population during the present study (1968–71), notable among which has been the disappearance of Endochironomus. Production studies of the two dominant larval Chironomidae (Glyptotendipes and Stictochironomus) in the sandy littoral area (42 per cent of the loch bed) gave annual estimates of 40·5 and 1·2 g (dry weight)/m2 respectively for 1970 and 5·0 and 10·2 g/m2 for 1971. Speculative estimates of the entire zoobenthos production in 1970 gave a value of 46·5 g/m2. The significance of these results is briefly discussed.

The Planktonic Activity of Larval Chironomidae in Loch Leven, Kinross

SynopsisThe planktonic movements of larval Chironomidae in Loch Leven, Kinross, are described, together with a provisional list of the species and age groups involved. The importance of this type of behaviour in determining the distribution of larval Chironomidae is discussed.

Food Habits of Hellgrammite Larvae, Corydalus cornutus (Megaloptera: Corydalidae), in the Brazos River, Texas1

Corydalus cornutus L. larvae ingested larvae of Simulium (25.8%). Cheumatopsyche (23.9%), and Hydropsyche (l9.0%) with greatest frequency. Chironomidae larvae and Simulium pupae were ingested at 6.8% frequency, and 17 other aquatic insect food groups were ingested at lower frequencies. There was little diurnal periodicity in feeding, except that Hydropsyche larvae appeared to he ingested at higher rates after dusk. Calculation of Forage Ratios and Ivlev's Electivity Index indicated positive selection or election for baetid mayflies (Isonychia), Hydropsyche and Simulium. Because of abundance of Cheumatopsyche in the environment and a functional response in its predator-prey interaction with C. cornutus, somewhat misleading negative selection was indicated by the indices for Cheumatopsyche. Chironomids were taken at random or were slightly preferred February-April but were highly preferred in May. Simulium larvae were positively selected except in April; Electivity Index for them in May was maximum (1.0), and a high Forage Ratio (33) was determined.

Review of Studies on Feeding of Aquatic Invertebrates Conducted at the Institute of Biology of Inland Waters, Academy of Science, USSR

The main results obtained at the Borok Institute during the last decade are reviewed. Food and methods of feeding by various aquatic invertebrates (Rotatoria, Oligochaeta, Mollusca, Cladocera, Copepoda, Chironomidae larvae), daily food consumption, and assimilation of food have been investigated. Most invertebrates are omnivores although some species live on only one type of food. Daily food consumption changes with food concentration, temperature, and size of consumer. At 15–22 C and a concentration of food close to optimum, mean daily rations of most invertebrates studied usually range from 25 to 100% of body weight. Only in pulmonary Gastropoda and silt-eating Tubificidae does it greatly exceed body weight. In rare cases, at very high concentration of food unusual in nature, the so-called "extra feeding" may take place under experimental conditions. For most invertebrates feeding on natural food at optimum concentrations, index of assimilation varies widely, but rarely exceeds 50%. The assimilability of plant food was 45–55% in the majority of investigated species and appears to be considerably higher when animal food is used.

THE DIEL DRIFT OF CHIRONOMIDAE IN AN ARTIFICIAL STREAM AND ITS RELATION TO THE DIET OF COHO SALMON FRY, ONCORHYNCHUS KISUTCH (WAULBAUM)

AbstractThe diel pattern of drifting adults, pupae, pupal exuviae, and larvae of Chironomidae in a stream was established. Emergence was trimodal for the common species (Cricotopus sp. and Psectrocladius sp.), and larval drift-rates increased almost two-fold in darkness. The concurrent diel consumption of Chironomidae by coho fry was examined. The fish appeared not to make use of the peak drift-rates of larvae. Closest temporal correspondence between drift and diet was shown by adults. Forage ratios demonstrated greater consumption of chironomids than would be expected from their proportions in the drift. The order of acceptance was pupae, adults, larvae, and exuviae. High degree of utilization of an item is attributed to flotation and visibility. The major determinants of how much food is taken from the stream are identified as: marginal residence of the fish, the occupation by the fish of slow-water feeding stations, and the visibility of food items.

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.

The effects of preservatives on the regurgitation of gut contents by Chironomidae (Diptera) larvae

The commonly used preservatives for chironomid larvae were found to cause regurgitation of the gut contents, the incidence of regurgitation being higher when the gut in at least two of the thoracic segments was full. The Tanypodinae larvae regurgitated more frequently than others, because of differences in their gut morphology, the nature of the food ingested, or a combination of both. Handling of the larvae also caused regurgitation. Increased predation by Tanypodinae larvae appeared if there was a delay between collection and preservation or examination of the samples. These problems can be overcome by rapidly freezing the samples immediately in either powdered solid carbon dioxide or liquid air.

Seasonal Abundance and Distribution of Benthic Fauna within a Pond

A Tennessee pond was sampled weekly from June 18 to August 20, 1968, to determine quantitative differences among benthic organisms in sampling depths and dates. Annelids (Oligochaeta), Chironomidae larvae, and Chaoboridae larvae were the dominant organisms collected. Preferred depths existed for each group of organisms. Chaoboridae and Chironomidae exhibited distinct seasonal variations in numbers, with the population decreasing throughout the summer. Chaoboridae were the most and Chironomidae the least numerous of the 3 groups.

Abundance and Microdistribution of Larval Chironomidae in Stabilizaton Lagoons1, 2

Two different population structures of larval Chironomidae present in a 3-celled vs. a 1 cell 1 stabilization lagoon were studied from 1964 to 1966 in Oregon. Statistical analysis of dredging results from the 3-celled lagoon showed that total larval abundance was greater in winter, greater in the primary cell, and consistently greater in peripheral zones. Significant differences in larval population densities showed the following order of abundance: Glyptotendipes barbipes (Staeger) > Chironumus riparius Meigen > Anatopynia dyari (Coquillett). The established order of abundance resulted from greater tolerance on the part of G. barbipes than either C. riparius or A. dyari for physicochemical stress. Moreover larval A. dyari required more space for growth and development than did the tube-dwelling species. Dredging data from the 1-cell lagoon showed that total larval abundance was greater in the summer, greater for G. barbipes than for A. dyari, and greater for G. barbipes in both peripheral and central zones. The absence of C.riparius populations resulted from sustained sewage loading. The main factors affecting midge populations in both lagoons are considered to be: sewage influent quality and quantity, depth of water, degree of peripheral slope, and availability of dissolved oxygen at the soil-water interface.

Measurement of radiation dose distribution in a pond habitat by lithium fluoride dosimetry.

Thermoluminescent dosimetry has been used to measure the radiation dose accumulated by Chironomidae larvae inhabiting a 19-m diameter pond contaminated with cesium-137. Small plastic tubes filled with lithium fluoride powder were arranged in parallel rows along the pond bottom. The accumulated gamma dose was greatest at the pond margin.

The food and feeding-habits of the Pochard, Aythya ferina

The food and feeding habits of Pochard ( Aythya ferina) are described, based on stomach analyses of 45 birds collected between 1st September and 31st January, on field observations, and on a survey of the literature. Pochard feeding inland were found to have fed mainly on Chara and Nitella species, and to a lesser extent on Potamogeton and Polygonum species, as well as on larvae of Chironomidae. A survey of the literature substantially agrees with these results. Pochard feeding in coastal areas, including brackish water situations, are likely to have been feeding on Ruppia and Zostera species, and probably also on various Mollusca. Information is given on feeding behaviour, with observations on the daily activity of Pochard, the methods of feeding, and the times and depths of diving. Changes in the distribution of wintering Pochard in Britain are described and related to changes in environment, e.g. drainage schemes, decrease in Zostera, new reservoirs, and gravel pits. The paper illustrates the need for up-to-date work on the Pochard, and how necessary it is to have particular knowledge of the bird's feeding behaviour and diet preferences when formulating conservation projects.

Plecopteracoluthus downesigen. et sp. nov. (Diptera: Chironomidae), a Species Whose Larvae Live Phoretically on Larvae of Plecoptera

AbstractIn a creek northwest of the Gatineau Hills (Quebec) larvae of Chironomidae (Diptera) were found living in phoretic association with the immature stages of Perlidae (Plecoptera). The larvae were reared to the adult stage in the laboratory. Life pattern and morphological comparisons are made with other phoretic and parasitic forms of Orthocladiinae and with certain other genera, and it is concluded that the form represents a new genus and species of Orthocladiini, and has probably originated from the common ancestors of the generaRheocricotopus,ParacricotopusandMicrocricotopus. Detailed descriptions are given of the imago, pupa and larva of this insect.

The Life Cycle of Bunoderella metteri (Allocreadiidae: Bunoderinae), a Trematode Parasite of Ascaphus truei

The life cycle of Bunoderella metteri Schell, 1964, an intestinal parasite of the tailed frog, Ascaphus truei Stejneger in the Pacific Northwest, is described. Eggs are unembryonated when laid. Miracidia do not hatch in water. Ophthalmoxiphidiocercariae develop in rediae in the fingernail clam, Pisidium idahoense Roper. Larvae and pupae of the caddisfly, Rhyacophila grandis Banks, and dipterous larvae of the family Chironomidae serve as hosts for the encysted metacercariae. Immature specimens of B. metteri were recovered from the intestine of experimentally infected, laboratory-reared Rana aurora Baird and Girard, and Ascaphus truei. The only known bunoderid life cycle is that of Bunodera luciopercae (Miiller, 1776) Liihe, 1909, an intestinal parasite of freshwater fishes, reported by Wisniewski (1958). In Europe the cercariae develop in rediae in the freshwater clams Sphaerium corneum Linn. and S. rivicola Lamarck, and encyst in several species of Cladocera and Copepoda. Fishes become infected by ingesting the infected crustaceans. This paper presents the life cycle of an additional species. Bunoderella metteri Schell, 1964, is an intestinal parasite of the tailed frog, Ascaphus truei Stejneger, in the Pacific Northwest. Studies on its life cycle were undertaken concurrently in Idaho and Oregon. MATERIALS AND METHODS Adults of Ascaphus truei were collected at night from cold mountain streams in northern Idaho, western Oregon, and eastern Washington. The frogs remained alive many weeks when kept in water at 40 to 50 F. The water was changed every few days and saved as a source of parasite eggs that had passed in the feces of the host. Eggs collected by the sedimentation technique were placed in petri dishes on moist filter paper. Larval stages of the parasite were studied alive. Vital dyes (neutral red and Nile blue sulphate) were used to observe gland and flame cells of the cercariae. Naturally infected first intermediate hosts, Pisidium idahoense Roper, were collected from the same localities. The clams were kept alive for many weeks in dishes containing cold stream water and Received for publication 14 December 1964. * School of Natural Sciences, Arizona State College, Flagstaff. t Department of Biological Sciences, University of Idaho, Moscow. + Department of Zoology, Oregon State University, Corvallis. about 0.5 inch decaying vegetation. Measurements are in microns unless otherwise indicated.