Publisher Summary The measurement of production is being employed as an indicator of the health of an ecosystem, assessing the effect of environmental pollution or other disturbance. Additionally, secondary production is of vital interest to natural resource administrators responsible for the management of wild populations utilized for both food and recreation and in inland waters, particularly for vertebrate fisheries. This chapter discusses a selected portion of aquatic production biology, secondary production in inland waters. The chapter focuses on three groups, fishes, zoobenthos, and zooplankton, which have received most attention, for which methodology has been best worked out, and which are of most immediate concern to man. The production of other secondary producers, including heterotrophic algae, bacteria and fungi, protozoans, amphibians, reptiles, and other aquatic vertebrates, such as some birds and mammals more commonly associated with the terrestrial environment, must await further advances and reviews by other specialists. The energy flow through these other groups may be extremely important.

Secondary Production in Inland Waters 1

Habitat and life history are critical elements in assessing the production dynamics of invertebrates and their role in aquatic ecosystems. We studied invertebrate productivity at two sites in a subtropical blackwater river (the Satilla) in the Lower Coastal Plain of Georgia, USA, and found that submerged wooden substrates, or snags, are heavily colonized by aquatic insects. We compared invertebrate productivity on the snag habitat with productivity in the sandy benthic habitat of the main channel, and the muddy benthic habitat of the backwaters. The size-frequency method was applied to individual taxa in order to determine total invertebrate productivity. Emphasis was placed on the importance of the length of larval life, or the cohort production interval, in determining biomass turnover rates. The diversity of taxa was much higher on the snag habitat than in either of the benthic habitats. Filter-feeding caddisflies (especially Hydropsyche spp.) and black flies (Simulium spp.) were the major consumers on the snag habitat. Several species of midges, mayflies, and beetles also were abundant. Total densities, standing stock biomass, and production were very high for primary consumers on snags. Annual production was 51.9 and 67.1 g m-2. yr- I (dry mass per surface area of snag, or effective habitat) for the two sites. Hellgrammites, dragonflies, and stoneflies were the major insect predators colonizing snags, and their production was 5.5 and 5.2 g m-2 yr-t (effective habitat). Annual pro- duction/biomass ratios (P/B) were usually 5-10 for insects that had univoltine or bivoltine life cycles. Annual P/B estimates were very high for midges (> 100) and black flies (>70), since length of larval life was estimated to be very short. The sandy-substrate benthos consisted almost exclusively of very small midges with oligochaetes of lesser abundance. Densities were quite high (>20 000/M2), but biomass was very low (I 100 mg/ m2 or less). Production of primary consumers was >11 g m-2 yr- t with a very high estimate of annual P/B (166-227). The major predators were Ceratopogonidae (biting midges) larvae with an annual production of 1.6-2.6 g.m-2 yr-t. The muddy-substrate benthos consisted primarily of oligochaetes (Limnodrilus) and midges. Annual production was 7-10 g.m-2 yr-t for primary consumers. The major predators were larger Tanypodinae midges. On a substrate surface area basis, standing stock biomass on snags was 20-50 times higher than in the sandy habitat and 5-10 times higher than in the muddy habitat. Production on snags was only 3-4 times higher than production in the benthic habitats, with higher annual P/B in the latter. The production estimates for the snag habitat are among the highest yet reported for lotic ecosystems, and it appears that production on snags is limited by available substrate. Habitat areas per length of shoreline were estimated so that we could approximate relative amounts of biomass and production for a stretch of river. Although the snag habitat accounted for only 6/6% of the effective habitat substrate over a stretch of river, it was responsible for over half of invertebrate biomass, and 15- 16% of production. Taxa within each habitat were categorized to functional feeding groups, and habitat-specific func- tional groupings were evaluated using numbers, biomass, and production. Filtering collectors pre- dominated on snags, and gathering collectors in benthic habitats. When corrected for habitat abun- dance, the distribution of biomass among filtering collectors, gathering collectors, and predators was very close. However, the distribution of production was 12% filtering collectors, 71% gathering collectors, and 17% predators. We suggest that production is the most meaningful parameter to consider in functional group analysis and that the use of numbers or biomass alone can sometimes result in misleading conclusions. As a middle order (5th-6th) stream, the distribution of production or biomass among functional groups in the Satilla River differs considerably from that predicted by the river continuum concept, predicting a high percentage of grazing consumers.

Invertebrate productivity in a subtropical blackwater river: the importance of habitat and life history'

Global regressions of ecological population densities on body mass for mammals and for terrestrial animals as a whole show that local population energy-use is approximately independent of adult body mass—over a body mass range spanning more than 11 orders of magnitude. This independence is represented by the slope of the regressions approximating –0.75, the reciprocal of the way that individual metabolic requirements scale with body mass. The pattern still holds for mammalian primary consumers when the data are broken down by geographic area, by broad habitat-type and by individual community. Slopes for mammalian secondary consumers are also not statistically distinguishable from –0.75. For any given body mass temperate herbivores maintain on average population densities of 1.5 to 2.0 times those of tropical ones, though slopes do not differ. Terrestrial animals of all sizes exhibit approximately the same range of population energy-use values. These results agree with those reported for population energy-budgets. It is suggested that rough independence of body mass and the energy-use of local populations is a widespread rule of animal ecology and community structure.

Interspecific allometry of population density in mammals and other animals: the independence of body mass and population energy‐use

Tanypodinae usually form an important component in subfossil Chironomidae assemblages but can be difficult to identify beyond subfamily level due to fragmentation of subfossil material. However, generic identification of most subfossil specimens can be achieved by reference to the arrangement of cephalic setae. This paper presents the first identification guide to Holarctic Tanypodinae genera based on the cephalic setae. A total of 33 genera is described and illustrated, of which 9 were previously undescribed, and 26 descriptions are based on new material. A total of 42 species is illustrated to show intrageneric and intraspecific variation. Improved taxonomic resolution will enhance the performance of chironomid-environmental variable inference models and chironomid biostratigraphy.

An identification guide to subfossil Tanypodinae larvae (Insecta: Diptera: Chrironomidae) based on cephalic setation

Factors affecting the winter survival of temperate-zone insects are reviewed. Certain species suffer high winter mortality especially in cold years, or in years with below normal amounts of insulating snow.Survival depends on the choice of winter microhabitat and on cold-hardiness, but also on biological features that have not previously been emphasized. These include behaviour that results in placement of overwintering eggs in less severe sites and manufacture of cocoons or other structures that retard inoculation by ice, or desiccation. The possible role of habitat heterogeneity in facilitating population survival is stressed.Microhabitats are characterized mainly with respect to temperature. They differ markedly among geographic areas and not only in midwinter conditions (including the extent of variation), but also in the time at which entry to the microhabitat in fall is necessary to avoid the risk of frost. The cues that govern entry into these microhabitats include negative phototaxis in many species but have not been subjected to quantitative analysis. Deeper layers are warmer in winter but warm up more slowly in spring and therefore some species, especially in arctic habitats where rapid vernal development is advantageous because the season is short, overwinter in superficial or insolated sites.Supposed mechanisms of cold- and freezing-injury and its avoidance are reviewed. There are several theories of freezing-injury: many modem theories focus on damage to the cell membrane, apparently caused by changes in cell volume induced during freezing. Injury is avoided by suppression of haemolymph nucleators (enhancing supercooling); or by a variety of methods, especially those involving solutes, minimising damage to frozen tissues. Among these solutes, the prevalence of glycerol in overwintering insects is not unexpected since glycerol is a normal metabolite in animals and can play several possible roles in cryoprotection.Cold-hardiness is metabolically costly because of these solute adjustments. The cold-hardiness of a taxon depends partly on climatic history during its evolution. Faunal composition at the highest latitudes reflects this dependence.The winter survival of many high-latitude insects varies rather widely from year to year; but the many detailed studies on cold-hardiness that have been made in the laboratory have seldom been related to natural mortality.The overwintering stage depends partly on the taxon. It is often fixed within a genus, but less closely within higher taxa. Proportionately more species overwinter as larvae at higher latitudes, especially when the life cycle lasts more than one year. Habitat also influences the overwintering stage: aquatic species generally overwinter as larvae, although species of temporary pools frequently overwinter as eggs. Overwintering in more than one stage is not common.This review suggests that winter survival of a group depends on latitude (or its climatic equivalent), habitat, and evolutionary history. It might therefore be especially useful to compare cold-hardiness, developmental rates, control of the life cycle and other features among species at the same latitude from each extreme of a series, that contrasts cold-hardy groups in stable habitats (such as Chironomidae) with aerial or vegetation dwelling groups that are not cold-hardy (such as Orthoptera). Future study of winter survival also demands more ecological data (overwintering stage, microhabitat, and conditions experienced there) for a larger sample of the fauna, and the simultaneous measurement of cold-hardiness.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/117A65342BABC6EFEC99A8226FE28958/S0008347X00020368a.pdf/div-class-title-modes-of-seasonal-adaptation-in-the-insects-i-winter-survival-div.pdf

Modes of seasonal adaptation in the insects. I. Winter survival

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Recherches sur les chironomides [Diptera] lacustres du massif de Néouvielle (Hautes-Pyrénées)

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Recherches sur les chironomides [Diptera] lacustres du massif de Néouvielle (Hautes-Pyrénées). Première partie. Systématique, écologie, phénologie

Une population de Sialis lutaria a ete etudiee de 1969 a 1971 dans le lac de Port-Bielh (2 285 m, Pyrenees-Centrales). Dix stades larvaires ont ete denombres. Le cycle de developpement dure trois annees. Les larves se nourrissent essentiellement de crustaces benthiques pendant la premiere annee, de chironomides et d'oligochetes les annees suivantes. La croissance larvaire s'effectue pendant l'isothermie d'automne. 66,7 % de l'accroissement intervient au cours de la troisieme annee. Le rapport PS/PF varie au cours de la croissance. La production annuelle nette atteint 5,12 kg/ha/PS. Elle represente les 2/3 de celle du chironomide dominant du lac. Le rapport P/B max = 1,34 montre une certaine stabilite; il est voisin de ceux precedemment trouves pour deux chironomides du meme lac.

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Cycle biologique et production de Sialis lutaria L. (Megaloptera) dans le lac de Port-Bielh (Pyrénées Centrales)

Des recoltes d'exuvies nymphales de Chironomides obtenues par derive dans 14 stations reparties sur les 178 km amont d'une riviere de basse montagne du Massif Central francais ont permis de recenser 109 especes. En ajoutant les 17 especes recoltees en vol par Gagneur (1976), 126 especes ont ete identifiees ce qui represente 31 % du total des especes d'invertebres du benthos. Avec 72 especes, la sous-famille des Orthocladiinae est particulierement bien representee notamment par les 3 genres les plus frequents et les plus diversifies : Eukiefferiella (14 especes), Cricotopus (16 especes) et Orthocladius (9 especes). La sous-famille des Buchonomyiinae et l'espece Buchonomyia thienemanni Fitt. sont citees pour la premiere fois en France. L'ecologie de plusieurs especes est precisee. La succession des especes apparait comme un phenomene continu ; on peut cependant reconnaitre 4 groupements avec leur biocenoses respectives, compatibles avec le systeme de zonation de Illies et Botosaneanu (1963).

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Récoltes d'exuvies nymphales de chironomides (Diptera) dans le Haut-Lot, de la source (1 295 m) au confluent de la Truyère (223 m)

up to 1990. The list includes recent and old synonyms. Some corrections and additions are added to regional lists pre­ viously published. The presentation facilitates a connection with the section dealing with Chironomid distribution in the Limnofauna Europaea (lilies 1978). With 598 recently recorded species, French territory is probably one of the richest areas of Europe for Chironomids.

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H. Laville

Papers

Recherches sur les chironomides [Diptera] lacustres du massif de Néouvielle (Hautes-Pyrénées)

Recherches sur les chironomides [Diptera] lacustres du massif de Néouvielle (Hautes-Pyrénées). Première partie. Systématique, écologie, phénologie

Cycle biologique et production de Sialis lutaria L. (Megaloptera) dans le lac de Port-Bielh (Pyrénées Centrales)

Récoltes d'exuvies nymphales de chironomides (Diptera) dans le Haut-Lot, de la source (1 295 m) au confluent de la Truyère (223 m)

Liste annotée des Diptères Chironomidés de France continentale et de Corse