Trichoptera Research Articles

10.1007/s11488-008-1010-2

The adaptive behavior line of investigation, which is considered as a bionic approach to development of systems of artificial intelligence, is characterized. One of the topical problems in the framework of this approach is the simulation of searching animal behavior. A general scheme of searching adaptive behavior with inertial switching between search tactics is presented. A particular model of searching behavior of larvae of caddis flies building a case-house from particles of different size and searching for gathering of suitable particles is investigated. The adequacy of the model to biological experimental data is shown, which is characterized by its specificity reflecting the memory data of larvae about both the sizes of last-processed particles and the general properties of the inertial switching.

Characterization of unique heavy chain fibroin filaments spun underwater by the caddisfly Stenopsyche marmorata (Trichoptera; Stenopsychidae)

The silks of both Lepidoptera and its sister order Trichoptera contain a homologue of heavy chain (H-fibroin), which is assumed to determine the physical properties of the fiber, such as elasticity and toughness. The long repetitive region of the H-fibroin caddisfly Stenopsyche marmorata shows a conspicuous hierarchical structure that is composed of huge units, which are mainly constructed from four large blocks (SA, SB, SC and SD) arranged in an orderly fashion. Each block contains short, distinct motifs such as SXSXSX(SX), GPXG(X)(1-3) or triplet GGX, which also occur in lepidopteran and spider filaments. The SA, SB and SC blocks have nearly fixed amino acid numbers, while the length of the SD block varies, usually due to a variable number of GPXGXXX repeats. The multiple sandwich structure that occurs in the SB block is assumed to be unique to the caddisfly and may be related to the use of silk in an aqueous environment. The overall average of hydrophilicity in the repetitive H-fibroin region of S. marmorata is -0.609, whereas hydrophobicity prevails in most lepidopteran H-fibroins. Gly (29.51%), Pro (11.28%) and Ser (10.90%) are the three predominant amino acids of H-fibroin, and the high content of essential amino acids reflects the energy-rich food resources of the caddisfly. The H-fibroin of S. marmorata is about 400-500 kDa and expressed in both the middle and posterior silk glands, which is different from the expression pattern in Lepidoptera species.

Physical properties and structure of aquatic silk fiber from Stenopsyche marmorata

To study the properties and structure of aquatic silk, nest-spinning hydropsychid caddisfly ( Stenopsyche marmorata) larva were collected from a Japanese river and the silk glands were removed from the larva by dissecting and dried on the glass plate at room temperature. The silk fibers were obtained by removing fibrous materials, which the aquatic insects spun at the bottom of glass container and the microstructure and physical properties of aquatic silk protein fibres and their solid silk protein gland were evaluated. Silk fiber produced by the caddisfly larvae is composed of two filament embedded in a layer of glue. The results of Fourier transform infrared spectroscopy and X-ray diffraction measurements suggested the existence of binary structure containing random coil conformation and additional minor β-molecular structure. Differential scanning calorimetry results are characterized by two broad endothermic transitions, at 230 °C and 320 °C, which corresponds to the decomposition of silk glue and silk fiber from caddis fly, respectively. The storage modulus ( E′) remained almost unchanged and nearly constant at above 60 °C until about 214 °C, where it began to show a sharp drop. A prominent relaxation peak appeared in the imaginary part of the modulus (loss peak at 230 °C), in response to the strong motional transitions exhibited by the silk fiber at this temperature. There was significant difference of tensile strength of single solid silk protein gland in dry and wet state. The results obtained are quite promising as a basis for possible future biotechnological and adhesive applications of aquatic silk.

A new species of Leptonema Guérin (Trichoptera: Hydropsychidae) from southeastern Brazil

The net-spinning caddisfly genus Leptonema Guérin contains about 120 species, making it the largest genus in the subfamily Macronematinae (Hydropsychidae) and one of the most diverse in the order Trichoptera (Flint et al. 1987; Flint 2008). Most species are large, with wingspans of about 60 mm. They inhabit all types of running waters and generally comprise a significant proportion of invertebrate biomass in these waterways (Flint et al. 1987). In the New World, the genus is extremely diverse, with 106 species widely distributed from the southwestern United States to northern Chile and central Argentina, including the Antilles (Flint 2008). Another 18 species occur in sub-Saharan Africa and Madagascar (Munõz-Quesada 1997). Flint, McAlpine & Ross (1987) revised the whole genus, and also considered biogeographic and phylogenetic aspects. Brazil has 26 recorded species (Paprocki et al. 2004; Flint 2008).

Benthic macroinvertebrate communities in agriculturally impaired streams.

Normal 0 false false false EN-US X-NONE X-NONE This work presents research into the taxonomic composition of macroinvertebrate communities in streams that are under the influence of agricultural pollution A total of 67 macroinvertebrate taxa (including 61 identified species) belonging to 40 families have been identified in the explored streams. The greatest species richness is recorded for the Trichoptera (18 species/1 taxa) and Mollusca (12 species). The molluscs Gyraulus albus, amphipods Gammarus pulex, caddisflies Hydropsyche pellucidula and oligochaetes are detected in all examined streams. There, the number of total benthic macroinvertebrate taxa is highly variable, ranging from 16 to 40. Results show that the examined streams depending on the benthic macroinvertebrate taxonomic composition and predominance of seperate macroinvertebrate groups undergo different pollution. Intolerant to pollution taxa such as Plecoptera, which are the most sensitive to pollution insects, have been found only in 5 of 12 examined streams and in low abundances. The richness and diversity of macrozoobenthos in some streams appear to respond to the water quality deterioration. The present study has found out that in the stream where the total macroinvertebrate taxa, EPT taxa richness are the lowest and a relative abundance of gatherers is the highest, the values of NH 4 -N, NO 3 -N, total N, PO 4 -P and total P in the stream water are the highest, too.

Distribution and migration of metals in trophic chains of the Yenisei ecosystem near Krasnoyarsk City

Methods of atomic absorption, flame photometry, and emission spectral analysis were used to study the concentrations of metals in water and major ecosystem components of the Yenisei River upstream of Krasnoyarsk City (conventionally background area). The mean bulk concentrations of Al and Cu in water exceeded the MAC for water bodies used for fishery. Cu concentration in freshwater shrimp was found to be reliably higher than that in the link of primary producers (periphyton), and Cd concentration in caddis fly larvae was found to exceed that in water moss. The maximal concentrations of metals among the examined aquatic organisms were recorded in periphyton. Cr concentration in the muscles of Arctic grayling was found to exceed some international standards.

Morphology of sternum V glands in three caddisfly species, Stenopsyche marmorata, Eubasilissa regina and Nemotaulius admorsus (Insecta: Trichoptera)

AbstractThe present study describes the morphology of the sternum V gland of three caddisfly species, Stenopsyche marmorata Navas, Eubasilissa regina (McLachlan) and Nemotaulius admorsus (McLachlan), each of which belongs to a different family of the order Trichoptera, using light and scanning electron microscopy. In both sexes of these three species, the gland orifices are located on the sides of the sternum V as crescent‐shaped slits, and are connected with the glandular tissue via cuticular gland ducts. The shapes of glands differ greatly among species; a slender ampullar form in S. marmorata, a flattened saccular form (horseshoe shape) in E. regina and a kidney shape in N. admorsus. The glands are composed of four essential components: large secretory cells, small reservoir cells, the lining of the reservoir and the gland duct. In S. marmorata and E. regina, additional components, muscle fibers, are present around the small reservoir cells. The secretory cells covering the whole outer surface of the gland are very large, and form many bunches in S. marmorata and E. regina, but do not form them in N. admorsus. The small reservoir cells lie inside the layer of the secretory cells and are tightly connected with the cuticular lining of the reservoir. The linings become thick cuticular ducts near the gland orifices. Histological features suggest that the secretory cells of the sternum V gland of Trichoptera belong to the type of class 3 cells in insect epidermal glands.

Bat activity affected by sewage effluent in Irish rivers

Bat activity and benthic macroinvertebrates were sampled at nine paired sites, upstream and downstream from sewage effluent discharges into Irish rivers. Bat activity was measured using broadband acoustic detectors and macroinvertebrates by three 30-s standard benthic kick samples per site. Biological indices of water quality were significantly lower downstream from sewage outfalls, relative to upstream. The soprano pipistrelle ( Pipistrellus pygmaeus) was significantly more active (as measured by bat passes per unit time) at downstream sites, while Daubenton’s bat ( Myotis daubentonii) was less active. These results contrast with those of a similar study in England, where P. pygmaeus were less active, and Myotis spp. were more active downstream from sewage outfalls. We suggest that P. pygmaeus were more active downstream in our study because of a preference for preying on small orthocladiinid Chironomidae (non-biting midges), which were significantly more abundant downstream. M. daubentonii may prefer Trichoptera (caddis fly), which were significantly more abundant upstream. Organic pollution may then affect bats, but its effect appears to be more complex than previously implied. Implications of changing nutrient levels in freshwaters for populations of M. daubentonii and P. pygmaeus may be different from what is currently suggested in the literature.

Prevalence-adjusted optimisation of fuzzy habitat suitability models for aquatic invertebrate and fish species in New Zealand

For many years, habitat suitability models for aquatic species have been derived from ecological datasets by model optimisation. Previous research showed that optimisation of the predictive model performance did not necessarily lead to ecologically relevant models due to the impact of the dataset prevalence. Therefore, the adjusted average deviation was presented as a performance criterion that allowed incorporation of ecological relevance in the model optimisation process. This paper aims to analyse the relation between the adjusted average deviation (aAD) and the training set prevalence for three species in different New Zealand river systems: caddis flies Aoteapsyche spp., large brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss. The aAD was implemented in a hill-climbing algorithm to optimise a fuzzy species distribution model for each species. Specifically, the hypotheses were tested that (1) similar relations between the aAD and the training set prevalence would be obtained, (2) training based on the aAD would lead to more accurate model predictions than training based on more frequently applied performance criteria such as CCI, and that (3) the final fuzzy model would produce a realistic model of habitat suitability. The approach in this paper may improve the transparency of the model training process and thus the insight into habitat suitability models. Consequently, this paper could lead to ecologically more relevant models and contribute to the implementation of these models in ecosystem management.

Effects of Timber Harvest on Aquatic Macroinvertebrate Community Composition in a Northern Idaho Watershed

Abstract Annual macroinvertebrate sampling was performed from 1994 to 2005 in the Mica Creek Experimental Watershed in northern Idaho to examine the relationship between contemporary timber harvest practices and the structure and diversity of aquatic macroinvertebrate assemblages. Four years of calibration, 4 years of postroad, and 4 years of postharvest (roads + harvest) data were used to analyze treatment effects. Metrics used to assess change included functional feeding group composition, organism densities, taxa richness indices, species diversity, and sediment tolerance indices. These assessments included changes to three macroinvertebrate taxa commonly used as bioindicators of stream habitat quality: Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddis flies) (EPT). In relation to pretreatment conditions, there were generally no major changes in functional feeding group composition or species diversity. Increases were observed in overall abundance and EPT abundance, but they largely can be explained by natural population variability. These results suggest that little or no change in macroinvertebrate communities resulted from road construction and timber harvest activities in the watershed. Substantial interannual variability was also observed, suggesting that infrequent biomonitoring may not provide adequate information to assess subtle disturbance effects in watersheds but can be an effective part of a comprehensive watershed monitoring program when coupled with other biotic and abiotic metrics.

Evidence for the role of methane‐derived carbon in a free‐flowing, lowland river food web

We measured the δ13C values of dominant primary consumers and their potential food sources in a groundwater‐fed lowland river. The δ13C of most consumers, such as Gammarus and Simulium, reflected that of the dominant forms of photosynthetic production, whereas the cased larvae of two caddis flies (Agapetus and Silo) were consistently 13C depleted (mean δ13C: ‐41.2% and ‐40.4%, respectively) throughout the year. The river water was supersaturated (approximately 50 times atmospheric) with methane, reflecting both supersaturation in the groundwater and local production in fine sediments. We measured appreciable rates of methane oxidation, relative to water only controls, in the biofilms on gravel, on the caddis fly cases, and on the bottom of larger rocks. In addition, there was a marked difference in the ratio of methane‐oxidizing potential to chlorophyll across those substrata. This ratio was below detection in the biofilm (i.e., no methane oxidation) on the tops of rocks, greater on the bottom of rocks, and maximal for the gravels and the caddis cases. If the caddis larvae acquire most of their carbon by grazing the tops of such rocks (where they are normally found), then they must acquire their depleted δ13C values by occasionally grazing biofilm where the ratio of methane oxidation to chlorophyll was much greater, and the most likely candidate is from their own or conspecific cases. Grazing methane‐oxidizing bacteria could provide the caddis larvae with up to 30% of their carbon, which could represent a true subsidy from an ancient groundwater source.

Alcathoe Bat (Myotis alcathoe) in the Czech Republic: Distributional Status, Roosting and Feeding Ecology

Between 2001 and 2008, we recorded Myotis alcathoe at nine sites within three distant areas in the Czech Republic. The species identification was confirmed with cyt b sequences and four distinct haplotypes were identified. All the localities exhibit surprisingly uniform habitat characteristics: (1) old full-grown oak-hornbeam forests, with (2) numerous large trees in advanced stages of decay are present, and (3) a very small to large water bodies and/or patches of riparian vegetation surrounded by the forest. Using radiotracking techniques, we discovered 27 day roosts of M. alcathoe, located mostly in big oak, birch and lime trees inside extensive forest stands. All roosts were fissures or small cavities in a tree trunk and in branches in the canopies, some 16m above the ground. Bats preferred trees that were higher, had higher canopy and canopy basement and had larger diameter at breast height than other available trees. Roost trees were surrounded by lower trees with lower canopy basements than available trees. Roost trees were in a poorer condition than other available trees. Roosts were occupied by up to 83 individuals in July but usually single individuals were found in the roosts in September. In contrast to syntopic M. mystacinus and M. brandtii, M. alcathoe has never been found in an anthropogenic roost (except for a fissure in concrete electricity pole). Preliminary analysis of the diet showed that nematoceran flies were the most important prey item along with spiders, caddis flies, small moths and neuropterans. In the observed ecological characteristics, M. alcathoe markedly differs from other European species of the genus Myotis. Its restricted habitat requirements are perhaps responsible for an islet-like pattern of its distribution and suggest an essential conservation value of the habitats of its occurrence.

Conservation of Silk Genes in Trichoptera and Lepidoptera

Larvae of the sister orders Trichoptera and Lepidoptera are characterized by silk secretion from a pair of labial glands. In both orders the silk filament consists of heavy (H)- and light (L)-chain fibroins and in Lepidoptera it also includes a P25 glycoprotein. The L-fibroin and H-fibroin genes of Rhyacophila obliterata and Hydropsyche angustipennis caddisflies have exon/intron structuring (seven exons in L-fibroin and two in H-fibroin) similar to that in their counterparts in Lepidoptera. Fibroin cDNAs are also known in Limnephilus decipiens, representing the third caddisfly suborder. Amino acid sequences of deduced L-fibroin proteins and of the terminal H-fibroin regions are about 50% identical among the three caddisfly species but their similarity to lepidopteran fibroins is <25%. Positions of some residues are conserved, including cysteines that were shown to link the L-fibroin and H-fibroin by a disulfide bridge in Lepidoptera. The long internal part of H-fibroins is composed of short motifs arranged in species-specific repeats. They are extremely uniform in R. obliterata. Motifs (SX)n, GGX, and GPGXX occur in both Trichoptera and Lepidoptera. The trichopteran H-fibroins further contain charged amphiphilic motifs but lack the strings of alanines or alanine-glycine dipeptides that are typical lepidopteran motifs. On the other hand, sequences composed of a motif similar to ERIVAPTVITR surrounded by the (SX)4-6 strings and modifications of the GRRGWGRRG motif occur in Trichoptera and not in Lepidoptera.

Phylogenetic relationships among the lepidopteran and trichopteran suborders (Insecta) from the embryological standpoint1

Adopting the cladistic method in comparative embryology, 27 embryonic characters were analyzed to reconstruct the phylogenetic relationships among the lepidopteran and trichopteran suborders, viz., Annulipalpia, Integripalpia, Zeugloptera, Dacnonypha, Exoporia, Monotrysia, and Ditrysia. The resultant cladogram is basically coincident with that proposed by Kristensen. The order Trichoptera and Lepidoptera constitute a monophyletic group on the basis of one synapomorphy, the presence of well developed silk glands in embryos. The Trichoptera are separable from the Lepidoptera by the states of four characters. The Trichoptera, as a whole, are quite homogenous, and embryological data provide no rational ground for the separation of this order into the Annulipalpia and Integripalpia at a subordinal level. On the contrary, the embryonic development of the Lepidoptera becomes divergent from the most primitive condition to a specialized one according to suborders. The Zeugloptera are the sister group of all other Lepidoptera, because they share two apomorphies with the latter. The Dacnonypha are the most primitive next to the Zeugloptera, and have a sister-group relationship with the Exoporia + (Monotrysia + Ditrysia), being held together with the latter by five synapomorphies. Although the Exoporia retain almost as many plesiomorphic characters as the Dacnonypha, they have a sister-group relationship with the Monotrysia + Ditrysia, as inferred on the basis of two synapomorphies. The Monotrysia and Ditrysia have a sistergroup relationship, and are the most advanced groups in the Lepidoptera judging from their shared acquisition of many apomorphic characters.

IgE Associated with Reaginic Antibodies to Various Allergens

Reaginic antibodies to ragweed are known to be associated with immunoglobulin E. A question remains to be answered if reaginic antibodies to other allergens are also in the immunoglobulin E class. Sera of 12 patients allergic to, grass (3), house dust (1), caddis fly (2), cantaloupe (2), pike (1), egg (1), and penicillin (2), were examined by means of absorption with insoluble immunoadsorbents containing monospecific antiserum to IgE, IgG, IgA, IgM, and IgD. Prior to absorption, all patients' sera, when examined by FTausnitz-Kustner (PK) test, demonstrated reaginic antibodies, in various titers, to the different allergens.

Do agricultural pollutants affect competition between filter‐feeding caddis fly larvae? Results of laboratory microcosm experiments

Summary1. Predictable changes in the composition of macroinvertebrate communities in response to non‐point source pollution are the basis of macroinvertebrate community indices. However, other factors, such as biotic interactions, also affect the composition of macroinvertebrate communities and may complicate the interpretation of such indices by interacting with abiotic stressors.2. The effect of agricultural pollutants on competition between two filter‐feeding caddisflies, Brachycentrus appalachia and Hydropsyche spp. was studied in the laboratory using recirculating flow tanks.3. Experiments were conducted at two densities of Hydropsyche: high (300 per tank) and low (80 per tank). Brachycentrus density was kept constant at 40 per tank in all experiments. Experiments assessed the effect of an agricultural pollutant mix (sand, cow‐manure compost mix) and the presence of the competitor on both taxa.4. The only negative response to pollutants was a larger number of Hydropsyche drifting in high‐density tanks. In fact, at high densities, mortality of Hydropsyche was higher in controls than in tanks receiving pollutants.5. Hydropsyche and B. appalachia competed for resources and the presence of pollution did not affect the outcome of this competition. The presence of high densities of Hydropsyche resulted in higher drift and lower condition of B. appalachia. At low densities of Hydropsyche, B. appalachia larvae suffered greater mortality and tended to be in poorer condition. Brachycentrus appalachia may be less successful at even moderate densities of Hydropsyche due to competition between these taxa, most likely for prime feeding positions.6. Streams receiving non‐point source pollution from agriculture may be able to support higher densities of Hydropsyche, which may further reduce the suitability of these habitats for B. appalachia.7. This experimental study suggests that competition may complicate interpretation of biotic indices, as changes in benthic invertebrate community structure normally ascribed to pollution may arise from intra‐specific competition.

Contributions to the aquatic insect (Insecta) fauna of some mountain lakes in the Taurus Range (Turkey)

In order to determine some limnological features of 12 mountain lake, two field studies were carried out on Taurus Mountains in 1996 and 1997. By the examining collected aquatic insect specimens systematically, 31 taxa belonging order Hemiptera (9), Ephemeroptera (3), Coleoptera (14) and Trichoptera(5) were determined. These taxa recorded as first time for the mentioned localities. Additionally, Limnephilus coenosus Curtis, 1834, Drusus annulatus (Stephenson, 1837) and Allogamus auricollis (Pictet, 1834) species belonging to order Trichoptera were new records for the Turkish fauna.

Diet and a developmental time constraint alter life-history trade-offs in a caddis fly (Trichoptera: Limnephilidae)

Environmental factors influence variation in life histories by affecting growth, development, and reproduction. We conducted an experiment in outdoor mesocosms to examine how diet and a time constraint on juvenile development (pond-drying) influence life-history trade-offs (growth, development, adult body mass) in the caddis fly Limnephilus externus (Trichoptera: Limnephilidae). We predicted that: (1) diet supplementation would accelerate larval growth and development, and enhance survival to adulthood; (2) pond-drying would accelerate development and increase larval mortality; and (3) the relationship between adult mass and age at maturity would be negative. Diet supplementation did lead to larger adult mass under nondrying conditions, but did not significantly alter growth or development rates. Contrary to predictions, pond-drying reduced growth rates and delayed development. The slope (positive or negative) of the female mass–age at maturity relationship depended on interactions with diet or pond-drying, but the male mass–age relationship was negative and independent of treatment. Our results suggest that pond-drying can have negative effects on the future fitness of individuals by increasing the risk of desiccation-induced, pre-reproductive mortality and decreasing adult body size at maturity. These negative effects on life history cannot be overcome with additional nutritional resources in this species.

Diurnal dynamics of emergence of caddis flies Agapetus ochripes curt and Hydroptila tineoides Dalm. in the Far North (Indera River, Kola Peninsula, Russia)

Diurnal dynamics of emergence of caddis flies Agapetus ochripes curt and Hydroptila tineoides Dalm. in the Far North (Indera River, Kola Peninsula, Russia)

Imaging polarimetry of glass buildings: why do vertical glass surfaces attract polarotactic insects?

Recently it was observed that the Hydropsyche pellucidula caddis flies swarm near sunset at the vertical glass surfaces of buildings standing on the bank of the Danube river in Budapest, Hungary. These aquatic insects emerge from the Danube and are lured to dark vertical panes of glass, where they swarm, land, copulate, and remain for hours. It was also shown that ovipositing H. pellucidula caddis flies are attracted to highly and horizontally polarized light stimulating their ventral eye region and thus have positive polarotaxis. The attraction of these aquatic insects to vertical reflectors is surprising, because after their aerial swarming, they must return to the horizontal surface of water bodies from which they emerge and at which they lay their eggs. Our aim is to answer the questions: Why are flying polarotactic caddis flies attracted to vertical glass surfaces? And why do these aquatic insects remain on vertical panes of glass after landing? We propose that both questions can be partly explained by the reflection-polarization characteristics of vertical glass surfaces and the positive polarotaxis of caddis flies. We measured the reflection-polarization patterns of shady and sunlit, black and white vertical glass surfaces from different directions of view under clear and overcast skies by imaging polarimetry in the red, green, and blue parts of the spectrum. Using these polarization patterns we determined which areas of the investigated glass surfaces are sensed as water by a hypothetical polarotactic insect facing and flying toward or landed on a vertical pane of glass. Our results strongly support the mentioned proposition. The main optical characteristics of "green," that is, environmentally friendly, buildings, considering the protection of polarotactic aquatic insects, are also discussed. Such "green" buildings possess features that attract only a small number of polarotactic aquatic insects when standing in the vicinity of fresh waters. Since vertical glass panes of buildings are abundant in the man-made optical environment, and polarotactic aquatic insects are spread worldwide, our results are of general interest in the visual and behavioral ecology of aquatic insects.