Diversity of Spring Invertebrates and Their Habitats: A Story of Preferences

Springs, as unique ecotonal habitats between surface and hypogean areas, are considered endangered aquatic ecosystems due to direct and indirect human impacts and climate change issues. They are distinctive water habitats that are often inhabited by a diverse but mostly stenotypic group of organisms. The present study considered 31 springs from the Apuseni Mountains (the Romanian Carpathians) that were classified as rheocrene, helocrene, and limnocrene based on their geomorphology and hydrology. Samples from three substrate types (rocks, sand, and bryophytes) were collected using standard methods for crenic invertebrates. A total of 64,462 individuals belonging to 17 invertebrate taxa were identified: aquatic worms, mollusks, crustaceans, water mites, and insects. Amphipoda and Diptera–Chironomidae were the dominant taxa in most springs. At a community level, patterns of habitat preference were demonstrated for 12 invertebrate groups using the standardized selection index (B) and expressed as the number of springs where a certain group selected rocks, sand, and/or bryophytes: Four groups exhibited preferences for bryophytes (Coleoptera, Diptera, Plecoptera, and Trichoptera), Ephemeroptera exhibited preferences for rocks, and Copepoda exhibited preferences for sand. Amphipoda, Platyhelminthes, and Ostracoda displayed preferences for all three substratum types, while Gastropoda, Hydrachnidia, and Oligochaeta recorded lower percentages in springs where habitat preferences were significant. In addition, crenic invertebrates were divided into three guilds, depending on their dispersion abilities in any stage of their life cycle: sedentary (not-winged groups), mobile (winged groups), and ectoparasites (water mites that were able to leave the springs on their winged hosts). Sedentary taxa recorded higher percentages of abundances and habitat preferences towards rocks and sand, while ectoparasites (Hydrachnidia) and the mobile guilds tended to prefer bryophytes. This segregation might be explained by individual adaptations to the particularities of each type of substratum, such as the bodily form of the copepods, which are well suited for sand interstices, a habitat that our data showed that they preferred. Our results represent novel contributions to the knowledge of habitat preferences of spring invertebrates from the Apuseni Mountains, adding value to similar data from the Western Carpathians, the Alps, and the Dinaric region

Diversity of Spring Invertebrates and Their Habitats: A Story of Preferences

Springs, as unique ecotonal habitats between surface and hypogean areas, are considered endangered aquatic ecosystems due to direct and indirect human impacts and climate change issues. They are distinctive water habitats that are often inhabited by a diverse but mostly stenotypic group of organisms. The present study considered 31 springs from the Apuseni Mountains (the Romanian Carpathians) that were classified as rheocrene, helocrene, and limnocrene based on their geomorphology and hydrology. Samples from three substrate types (rocks, sand, and bryophytes) were collected using standard methods for crenic invertebrates. A total of 64,462 individuals belonging to 17 invertebrate taxa were identified: aquatic worms, mollusks, crustaceans, water mites, and insects. Amphipoda and Diptera–Chironomidae were the dominant taxa in most springs. At a community level, patterns of habitat preference were demonstrated for 12 invertebrate groups using the standardized selection index (B) and expressed as the number of springs where a certain group selected rocks, sand, and/or bryophytes: Four groups exhibited preferences for bryophytes (Coleoptera, Diptera, Plecoptera, and Trichoptera), Ephemeroptera exhibited preferences for rocks, and Copepoda exhibited preferences for sand. Amphipoda, Platyhelminthes, and Ostracoda displayed preferences for all three substratum types, while Gastropoda, Hydrachnidia, and Oligochaeta recorded lower percentages in springs where habitat preferences were significant. In addition, crenic invertebrates were divided into three guilds, depending on their dispersion abilities in any stage of their life cycle: sedentary (not-winged groups), mobile (winged groups), and ectoparasites (water mites that were able to leave the springs on their winged hosts). Sedentary taxa recorded higher percentages of abundances and habitat preferences towards rocks and sand, while ectoparasites (Hydrachnidia) and the mobile guilds tended to prefer bryophytes. This segregation might be explained by individual adaptations to the particularities of each type of substratum, such as the bodily form of the copepods, which are well suited for sand interstices, a habitat that our data showed that they preferred. Our results represent novel contributions to the knowledge of habitat preferences of spring invertebrates from the Apuseni Mountains, adding value to similar data from the Western Carpathians, the Alps, and the Dinaric region

Particularities of the <i>Hermetia illucens</i> (L.) (Diptera: Stratiomyidae) Ovipositing Behavior: Practical Applications

The industrial rearing of Hermetia illucens offers sustainable solutions to the acute challenges of modern society associated with the accumulation of increasing amounts of organic waste, the substantial reduction of natural ocean fish stocks, and the imminent food crisis. Detailed knowledge of the reproductive particularities and reproductive behavior of the species is essential for increasing the efficiency of the breeding technology. This study aimed to identify the affinity shown by females regarding the size of the oviposition slots (1, 2, 3, 4 and 5 mm), the vertical distribution of the ovipositing rate, and the influence of the substrate’s moisture on ovipositing behavior (dry matter/water: 1:0.5; 1:1; 1:1.5; 1:2). Over 90% of females oviposited in the 1-, 2- and 3-mm slots, with most of the eggs (58.57%) being oviposited in the 1-mm slots. There was a positive correlation between the size of the oviposition slots and the average weight of the clutches (r = 0.985). The vertical distribution of ovipositing followed a fluctuating trend, with a tendency to oviposit closer to the attractive substrate. The females avoided ovipositing close to substrates with low humidity (1:0.5); indeed, only 6.8% oviposited under these conditions, the differences being significant compared to substrates with higher humidity (p p H. illucens, which allow for a differentiated harvest of large-sized clutches, providing practical applications with significant impact on the economic efficiency of the species’ industrial growth technology