Trophic relationships among three species of ornamental fish from the region of Lake Amanã, Amazon

The present study objectified to evaluate the trophic relationships and the possible aggressive mimicry involving Carnegiella strigata, Carnegiella marthae and Gnathocharax steindachneri, in lowland forest streams. Samplings occurred in November 2002, March and August 2003 in Amanã Sustainable Development Reserve (ASDR). The total of 943 fish was caught, being 79.43% of C. marthae, 3.18% of C. strigata and 17.39% of G. steindachneri. Stomach contents, degree of stomach repletion, relative volume and frequency of occurrence of food items were evaluated. Thirteen food items were identified, and the presence of terrestrial and aquatic insects indicates the high dependence of these species and the flooded forest. Low feeding overlap was observed between Carnegiella strigata and C. marthae compared to Gnathocharax steindachneri. However, the overlap between the two Carnegiella species was relatively high, which could explain the low frequency of syntopic occurrence among these species, suggesting a possible case of competitive exclusion.

Edible Aquatic Insects: Diversities, Nutrition, and Safety

Edible insects have great potential to be human food; among them, aquatic insects have unique characteristics and deserve special attention. Before consuming these insects, the nutrition and food safety should always be considered. In this review, we summarized the species diversity, nutrition composition, and food safety of edible aquatic insects, and also compared their distinguished characteristics with those of terrestrial insects. Generally, in contrast with the role of plant feeders that most terrestrial edible insect species play, most aquatic edible insects are carnivorous animals. Besides the differences in physiology and metabolism, there are differences in fat, fatty acid, limiting/flavor amino acid, and mineral element contents between terrestrial and aquatic insects. Furthermore, heavy metal, pesticide residue, and uric acid composition, concerning food safety, are also discussed. Combined with the nutritional characteristics of aquatic insects, it is not recommended to eat the wild resources on a large scale. For the aquatic insects with large consumption, it is better to realize the standardized cultivation before they can be safely eaten.

Description of Some Aquatic Insect Genera in Greater Zab River Branches, North of Iraq

Aquatic insects samples were collected from 6 sites along the Greater Zab River in the northern Iraq from Duhok and Erbil governorates over 12 months during September 2016 to August2017, which belong to seven orders (Ephemeroptera, Plecoptera, Trichoptera, Odonatan, Diptera, Coleoptera, and Megaloptera). Clustering mitochondrial DNA cytochrome c oxidase and 16S rDNA genes, morphological keys, and matches in the Barcode of Life Database, we identified 24 species return to 7 orders and 12 families, as indicated in the results. The reported species were: Ephemeroptera 5 members of the family Heptageniidae (Maccaffertium meririvulanum, Raptoheptagenia cruentata, Ecdyonurus dispar, Anepeorus rusticus, Stenonema femoratum), 1 Ephemerellidae (Seratella ignita), 1 Arthropleidae (Arthroplea bipunctata), 6 Baetidae (Baetis alpinus, Baetis braaschi, Baetis noa, Baetis harrisoni, Iswaeon anoka, Heterocloeon amplum), 1 member for each of Diptera, Coleoptera, Megaloptera and Odonatan orders, while Plecoptera 2 members Leuctridae (Leuctra hippopoides, Leuctra inermis) and Tricoptera 4 members 3 Hydropsychidae (Leptonema albovirens, Hydropsyche simulans, Arctopsyche irrorate), 1 Hydroptilidae (Ochrotrichia tenuata). Most of these recorded species and genera were mentioned for the first time and represent new records in Iraq. Presence and distribution of identified species varied between studied sites, as a result of differences in biogeographical and physical conditions.

Diversity of aquatic insects and biomonitoring of water quality in the upper Ganga River, a Ramsar site: a preliminary assessment

Monitoring of freshwater habitats through aquatic insects is widely used. A study was carried out in March, 2019 at 14 sites in the Upper Ganga River between Brijghat and Narora, a riverine Ramsar site in India, to document the diversity of three major aquatic predatory insect groups—Odonata, Coleoptera, and Hemiptera—and determine their biomonitoring potential. The study recorded three species of Coleoptera, four Hemiptera, 14 dragonflies, and eight damselflies. The Shannon diversity index (H′) ranged from 2.465 to 2.782, Pielou’s Evenness index (J′) from 0.841 to 0.894, and Berger–Parker index of dominance (d) from 0.122 to 0.243. Families Libellulidae (Odonata), Coenagrionidae (Odonata) and Gerridae (Hemiptera) had high relative abundance and dominant status. The stream invertebrate grade number-average level (SIGNAL2) score (for family) ranged from 2.316 to 3.174, lying within quadrant 2 of the SIGNAL2 (family) quadrant diagram. This suggested that the water in the area is likely to have high levels of turbidity, salinity, or nutrients, caused naturally or by anthropogenic activities, and the water has low levels of most toxic chemicals.

Trajectories of aquatic insect functional groups along the resistance/resilience axis when facing water flow changes

1. Understanding how differences in intensity and frequency of hydrological disturbances affect the resistance and resilience of aquatic organisms is key to manage aquatic systems in a fast-changing world. Organisms’ responses to environmental changes can be influenced by different life strategies. Some aquatic organisms have strategies that improve the permanence in aquatic systems, while others use strategies that enhance colonization. 2. Therefore, we carried out a manipulative experiment to understand the resistance/resilience of aquatic insects based on their functional characteristics to hydrological disturbances in streams in the Cerrado hotspot. 3. We placed 200 artificial substrates in five streams and submitted them to changing water flow regimes that differed both in frequency and intensity. Then we observed the response of the aquatic community for 39 days. We used a Hierarchical Bayesian strategy approach to estimate the probabilities of permanence and colonization of each life strategy group (nine groups). 4. We observe that the most intense changes in the water flow tend to affect the permanence of almost all groups. However, this effect was reduced in intensity over time. On the other hand, less frequent disturbances, regardless of intensity, tend to reduce the permanence of most groups of aquatic insects over time. The difference in the effect of disturbance regarding intensity (higher or lower) may be related to a greater dispersal capacity of some groups. 5. These results are worrisome in a scenario of reduced riparian vegetation around streams and with the expectation of precipitation to become more concentrated in shorter periods of time due to climate change in the Cerrado hotspot. Together, these anthropogenic changes tend to increase the effect of runoff on the lotic systems and, consequently, reduces the permanence of many groups of aquatic insects in their habitat, particularly those with traits associated with permanence.