Neocaridina Davidi Research Articles

Confirmed by integrative taxonomy first and unusual occurrence of the exotic shrimp Neocaridina davidi (Caridea: Atyidae) in Brazil

A shrimp specimen of the genus Neocaridina Kubo 1938, originally from Asia, was collected for the first time in a natural marine environment in Pernambuco, Brazil. This represents the first record of this genus in the South American continent. Morphological characteristics and mitochondrial and nuclear DNA sequences (COI, 16S, 18S, and H3) of the specimen were compared with other species of Neocaridina, enabling its identification as Neocaridina davidi. Finding this freshwater species native to mainland China in a marine environment was surprising. Based on prior findings in other locations, the most likely hypothesis for this unusual occurrence is that the shrimp may have been released intentionally or unintentionally into the environment by an aquarium hobbyist.

To invest or not to invest, that is the question: male presence and genetic relatedness as modulators of female reproductive effort in a shrimp

The present work was aimed at evaluating whether females of a freshwater shrimp, Neocaridina davidi (Bouvier, 1904), allocate differentially to reproduction when reared in the presence of males and in the presence of brothers/non-brothers. Ovarian growth was evaluated in three consecutive maturation cycles. The composition of biochemical reserves was determined in the eggs (i.e., embryos) laid at the end of the first cycle, in 20-day-old juveniles produced at the end of the second cycle, and in the mature ovary of females at the end of the third cycle. When reared in the absence of males, females took longer to mature the ovaries and stored less proteins, triglycerides, and cholesterol in the mature ovary. Females reared with brothers took longer to mature the ovaries than females reared with non-brothers, with no differences in the biochemical composition of their mature ovaries. The eggs produced by females mated to brothers showed a lower carotenoid content, higher cholesterol content, and a tendency towards lower energy content than those produced by females mated to non-brothers. These results suggest that females are capable of recognizing kin and modulate primary reproductive effort, in terms of ovarian and egg biochemical composition, according to male presence and genetic relatedness.

Invisible invaders: range expansion of feral Neocaridina davidi offers new opportunities for generalist intracellular parasites

The release of ornamental pets and associated pathogens outside their native range might directly or indirectly impact the recipient community. In temperate regions, e.g., central Europe, feral freshwater species of tropical and sub-tropical origins are mainly constrained to thermally polluted waters and thermal springs. However, species with high environmental plasticity and reproduction rates, such as the shrimp Neocaridina davidi, may adapt to colder water regimes over time. A widening thermal niche may eventually overcome thermal barriers, further expanding the range and enhancing transmission opportunities for host generalist parasites. This study assesses the observed (field observations) and theoretical (species distribution models) range expansion of N. davidi and associated parasites in Europe. We report three newly established N. davidi populations from thermally polluted waters in central Europe (Germany, Hungary, and Slovakia) and provide further evidence of its range expansion into colder environments. Species distribution models predict thermally suitable habitats in the Mediterranean and a foreseeable expansion into Western Europe and the Balkans by 2050. We confirm the presence of the microsporidian parasite Ecytonucleospora hepatopenaei in feral N. davidi populations across Europe and expand the list of microsporidians found in this host from two to four. Furthermore, we provide the first evidence of parasite spillover from/to the invasive crayfish Procambarus clarkii, suggesting that parasite exchange with native biota might be possible. Such possibility, coupled with an ongoing range expansion of N. davidi bolstered by human-mediated introductions and climate change, will likely exacerbate the impact on native biota.

The coloration of Neocaridina davidi (Bouvier, 1904) (Caridea, Atydae) fed with live microalgae Haematococcus pluvialis and the cyanobacteria Spirulina (Arthrospira) platensis

Haematococcus pluvialis synthesizes and accumulates astaxanthins, while Spirulina (Arthrospira) platensis produces phycocyanins. The ornamental shrimp Neocaridina davidi is commercially important for its variety and intensity of coloration. We evaluate the effect on the coloration of N. davidi by consuming H. pluvialis and S. platensis as a food supplement to preserve their nutritional quality. H. pluvialis was subjected to stress to obtain aplanospores with astaxanthin. Live microalgae were included in gelled spheres to provide them as a supplement to three-day-old N. davidi juveniles with different phenotypes: wild (NdW), red (NdR), and blue (NdB). The experiment involved the commercial food supply and spheres with or without microalgae for 31 days. Chromatophores present in the uropod of each phenotype were examined, their number and expansion estimated, and the area covered by optical density (OD). Results show that H. pluvialis reached a greater astaxanthin accumulation on day 30. The coloration of the NdR and NdB phenotypes improved by consuming microalgae, increasing the OD in the uropod. NdB phenotype showed better coloration when consuming S. platensis (56.2%), while the NdR phenotype was more favored when consuming H. pluvialis (74.2%). The chromatophores expanded their area by doubling in the NdR and NdB phenotypes, where H. pluvialis increased its intensity four times in NdR. The number of chromatophores was significant only in NdR with S. platensis. In conclusion, gelling is a viable method to preserve the nutritional quality of live microalgae and transfer bioactive compounds that improve the coloration of N. davidi.

Development and testing of a sedation protocol for Neocaridina davidi

Neocaridina davidi, a small freshwater shrimp native to Asia, specifically China, Japan, Korea, and Vietnam, possesses remarkable resistance to poor water quality and offers various advantages over other invertebrate species to examine crucial issues in neuroscience and other related areas. These advantages include robustness, ease of maintenance, and transparency, making them useful for in vivo studies with optical imaging techniques. Despite its suitability for research purposes, particularly in the fields of imaging and fluorescent techniques, the lack of attention given to this species has resulted in the absence of a robust and replicable sedation protocol for immobilization and safe manipulation. Consequently, researchers face challenges in performing experimental procedures while minimizing harm to this specimen. In this study, we have developed and evaluated a simple sedation protocol specifically designed for Neocaridina davidi, assessing its effectiveness using light microscopy and image processing.

Among-individual behavioural variation in the ornamental red cherry shrimp, Neocaridina heteropoda.

Personality variation, defined as among-individual differences in behaviour that are repeatable across time and context, is widely reported across animal taxa. From an evolutionary perspective, characterising the amount and structure of this variation is useful since differences among individuals are the raw material for adaptive behavioural evolution. However, behavioural variation among individuals also has implications for more applied areas of evolution and ecology-from invasion biology to ecotoxicology and selective breeding in captive systems. Here, we investigate the structure of personality variation in the red cherry shrimp, Neocaridina heteropoda, a popular ornamental species that is readily kept and bred under laboratory conditions and is emerging as a decapod crustacean model across these fields, but for which basic biological, ecological and behavioural data are limited. Using two assays and a repeated measures approach, we quantify behaviours putatively indicative of shy-bold variation and test for sexual dimorphism and/or size-dependent behaviours (as predicted by some state-dependent models of personality). We find moderate-to-high behavioural repeatabilities in most traits. Although strong individual-level correlations across behaviours are consistent with a major personality axis underlying these observed traits, the multivariate structure of personality variation does not fully match a priori expectations of a shy-bold axis. This may reflect our ecological naivety with respect to what really constitutes bolder, more risk-prone, behaviour in this species. We find no evidence for sexual dimorphism and only weak support for size-dependent behaviour. Our study contributes to the growing literature describing behavioural variation in aquatic invertebrates. Furthermore, it lays a foundation for further studies harnessing the potential of this emerging model system. In particular, this existing behavioural variation could be functionally linked to life-history traits and invasive success and serve as a target of artificial selection or bioassays. It thus holds significant promise in applied research across ecotoxicology, aquaculture and invasion biology.

Toxic effects of nickel on tolerance and regeneration in the freshwater shrimp Neocaridina davidi

Heavy metals cause environmental pollution and produce toxic effects on organisms. Nickel (Ni) is a common metallic pollutant of aquatic ecosystems and potentially can produce multifarious changes in the body of aquatic organisms. The average nickel content in rivers is about 0.7 μg/l. As a result, the homeostasis of the affected organism is disturbed, and processes that can counteract the changes are activated. To better understand the effects of Ni in the freshwater environment and its fauna, it is important to establish whether all changes caused in cells and tissues by Ni exposure are reversible when the animal returns to the non-polluted environment. Thus, the main aim of the study was to analyze changes that occur after Ni exposure and after it is returned to non-contaminated water at various levels of the animal’s body. The freshwater shrimp Neocaridina davidi (Crustacea) was selected as the subject of the study. As the organ for studies, we chose the midgut because it is a barrier against stressors that enter the organism. A concentration of 3.63 mg Ni/l was selected for the experiment, at which approximately 50% mortality of the population was observed after 14 days. The midgut was analyzed using light and transmission electron microscopy (TEM), confocal microscopy, and flow cytometry for qualitative and quantitative results. When the organisms were transferred to clean water, a prolong exposure resulted in a decrease in the values of the analyzed parameters (e.g. ROS, cell death, etc.) proportional to the purification time. The recovery time was insufficient to return to control values in most analyzed groups. Nevertheless, the occurrence of regenerative changes suggests that freshwater shrimps are relatively tolerant to nickel, when the exposure time is short and the recovery time is long.

Annoying noise: effect of anthropogenic underwater noise on the movement and feeding performance in the red cherry shrimp, Neocaridina davidi

Anthropogenic noise in marine and freshwater environments has increased dramatically, with a range of negative impacts and detrimental consequences on many aquatic animals across taxa. Benthic organisms, including many invertebrates, can sense underwater sounds, yet the responses they trigger in these organisms have received little attention. We conducted two laboratory-based experiments to investigate the effect of underwater sound playback on the movement behavior and feeding performance of the red cherry shrimp Neocaridina davidi as a model of freshwater decapod. Movement speed decreased significantly upon opening the divider in both the sound and control treatments. However, there were no significant sound-dependent changes overall between the control and sound treatments. The spatial distribution of shrimp in response to the sound treatment showed significant changes; shrimp spent more time at the farthest one-third position from the sound source. Feeding latency (latency to find food) also increased in the sound treatment compared to the control. Moreover, in terms of the number of successes and failures in finding the food source in the control treatment, significantly more shrimp succeeded in finding the food source. The number of revisits to the food source decreased in the sound treatment compared to control and more shrimp were significantly distracted in the sound treatment. Our study highlights the potential for human-made sound to impact on crustacean activity. Thus, they are prone to the impacts of anthropogenic noise, causing negative impacts on their movement-swimming activities, and feeding behavior. Behavioral changes observed, namely altered feeding and locomotory behavior may have wider-reaching negative effects, including detrimental impacts on animal fitness.

Long-Term Exposure of the Red Cherry Shrimp Neocaridina davidi to Diclofenac: Impact on Survival, Growth, and Reproductive Potential.

The current study was aimed at studying the long-term effects of diclofenac on the freshwater shrimp Neocaridina davidi, concerning survival, somatic growth, and reproduction. In this study, both ovigerous females and males of this species were exposed for 63 d to 0 (control), 0.1, or 1mg/L of diclofenac. At the highest concentration, significant mortality was detected, and the somatic growth of females was significantly decreased. The percentage of females with a second spawn, observable from day 45, significantly increased at 1mg/L, while the time between spawns was significantly reduced at both concentrations assayed. However, the gonadal analysis made at the end of the assay in the surviving females showed a significantly lower proportion of advanced oocytes in females exposed to 1mg/L, as compared to control. Concerning hatching, the percentage of ovigerous females that could have successful hatching was reduced at 1mg/L of diclofenac, especially for the first spawn. For the second spawn, the low number of juveniles hatched from females exposed to 1mg/L also showed a significantly higher incidence of morphological abnormalities, such as hydropsy and underdeveloped appendages. Taken together, these results showed that even when diclofenac was able to produce earlier spawns, the reproductive output of each spawn was reduced.

Epibiont Cohabitation in Freshwater Shrimp Neocaridina davidi with the Description of Two Species New to Science, Cladogonium kumaki sp. nov. and Monodiscus kumaki sp. nov., and Redescription of Scutariella japonica and Holtodrilus truncatus.

This contribution presents the occurrence of epibiotic species associated with Neocaridina davidi shrimp collected in the wild, aquaculture ponds, and aquaria. A total of 900 shrimp are imported from Taiwan, three-quarters of which host at least one of the recorded epibionts. Among those epibionts, two species new to science are discovered, Cladogonium kumaki sp. nov. and Monodiscus kumaki sp. nov., while the other two, Holtodrilus truncatus and Scutariella japonica, are redescribed. The largest number of epibionts is found in shrimp collected from aquaculture ponds and the lowest in individuals from aquaria. Epibiont occurrence differs across designated microhabitats. The epibionts may be introduced alongside their host outside their native range, and their presence may affect shrimp breeding rates. Thus, more control over them should be provided. Their spread can be limited by removal from the host during molting or manually, as well as by using interspecies interactions.

Effect Of Market Vegetable Waste Fermented Feeding On The Growth Of Red Cherry Ornamental Shrimp (Neocaridina davidi)

Red Cherry ornamental shrimp (Neocaridina davidi) is a freshwater ornamental shrimp that is in great demand for aquascape. Feed is one of the variables with the highest cost in the Red Chery ornamental shrimp farming business. This study was conducted to determine the effect of fermented feeding market vegetable waste on the growth of Red Cherry ornamental shrimp. This research was conducted in June-July 2021 using a Complete Random Racangan with 5 treatments and 3 tests at the Laboratory of the Faculty of Fisheries and Marine Sciences, Jenderal Soedirman University. The treatment given is the feeding of fermented feed from waste mustard, carrots, bean sprouts, and cabbage vegetables, as well as the feeding of spirulina as a control treatment. The observed parameters are absolute length and weight gain, specific growth rate, survival and water quality. The data from the study were analyzed statistically with the F ANOVA Test and the tukey test if there were differences between treatments. The results showed that the control treatment obtained markedly different results (P>0.05) from other treatments for absolute length and weight growth parameters. Bean sprouts vegetable waste gives the best yield (6.8±0.22%) for a specific growth rate. The survival rate value between treatments did not show any significantly different results (P<0.05). Water quality parameters in the maintenance medium are classified as feasible for the life of Red Chery ornamental shrimp. In this study, feed from fermented bean sprouts vegetable waste can provide the best growth for Red Chery ornamental shrimp

Impacts of sublethal concentrations of 17 α-ethinylestradiol (EE2) on growth, reproductive performance, and survival in red cherry shrimp Neocaridina davidi (Crustacea, Atyidae) during consecutive spawnings

This study was conducted for the first time to investigate the long-term impacts of sublethal concentrations of 17 α-ethinylestradiol (EE2) on growth, survival, and reproductive performances in a model shrimp, the red cherry (Neocaridina davidi), females during five successive spawning steps for 7.5 months. Females were distributed in eighteen aquariums and continuously exposed to EE2 at six nominal concentrations of 0 (control), 0.02, 0.2, 2, 20, and 200 μg/L. Growth indices increased up to 0.2 μg/L and then sharply declined up to 200 μg/L. Most reproductive indices significantly decreased at levels > 0.02–0.2 μg/L with increasing EE2 levels. The highest absolute, relative, and actual fecundity values were recorded in the control, with the lowest value at 200 μg/L. With increasing EE2 levels, mean egg volume showed an increasing trend from the third spawning event onwards. Except for the time required to reach the first spawning, inter-spawning intervals considerably decreased with increasing EE2 levels at > 0.2 μg/L, especially from the third spawning stage onwards. Survival of exposed females significantly decreased with increasing EE2 levels. Unlike the body size, the juvenile's survival rates in all exposed treatments were considerably lower than the control. Females at concentrations 0.02–0.2 μg/L gained more body weight and length but produced fewer eggs with lower hatching percentages during five consecutive spawns. The results suggest that EE2 depending on the concentrations can cause unbalanced growth, reduce reproductive performances, especially from the third stage of spawning onwards, and reduce survival rates in brooders and subsequent offspring. In terms of growth, survival, and reproductive indices over successive spawns in ecotoxicology studies, the concentrations of 0.02–0.2 μg/L can be considered as chronic levels, but higher levels may have detrimental effects.

Symbiotic effect of Bacillus clausii and Galacto-oligosaccharide on growth and survival rates in red cherry shrimp (Neocaridina davidi)

In this 30-day experiment, the effect of probiotics (Bacillus clausii, commercial probiotics: Enterogermina) and prebiotics (Galactooligosaccharides, GOS) on the growth of red cherry shrimp (Neocaridina davidi) has been investigated for 30 days. The trial was conducted with 270 red cherry shrimps (initial weight: 0.24±0.03 g) in 27 plastic tanks (volume 0.01 m3 and area of 0.05 m2) representing 9 groups. Except for the control group, diets were supplemented with either GOS or synbiotics per kg of feed as G1 (1g GOS), G2 (2g GOS), G3 (3g GOS), G4 (4g GOS), G1P (1g GOS+ 1 ml probiotic), G2P (2 g GOS+ 1 ml probiotic), G3P (3 g GOS+ 1 ml probiotic) and G4P (4 g GOS+ 1 ml probiotic). This study showed significantly (P< 0.05) higher growth rate indices of male and female shrimps fed with feed additives groups compared to the control group. The highest final body weight, weight gain, and specific growth rate in male shrimps were recorded from the 2 g GOS+ 1 ml probiotic and 3 g GOS+ 1 ml probiotic groups. Similarly, the highest final body weight, weight gain, and specific growth rate in the female shrimps were found in the G1P and G2P synbiotic groups. Conversely, the lowest final body weight, weight gain, and specific growth rate of both the female and male groups were noted in the control groups. Regarding feed conversion ratio and survival rates of both female and male shrimps, G2P and G3P groups showed significant improvements. Regarding our study's findings, 2 g GOS and 1 ml of Bacillus clausii (commercial probiotic: Enterogermina) dietary synbiotics can be used to improve red cherry shrimp growth rates.

Functional analysis of ABCG2 gene in pigment transport of Neocaridina denticulata sinensis

Many strains of Neocaridina denticulata sinensis (cherry shrimp) possess vivid body colors.However, the molecular underpinnings of these various body colors are scarcely understood. To study the role of the ABCG2 gene in the pigmentation of cherry shrimp, four strains (red, yellow, blue, and wild strains) were sampled. The sequence and expression pattern of ABCG2in tissues and embryos were analyzed, and the distribution of ABCG2 was also explored via WFISH (whole mount flurescence in situ hybridization). And further, RNA interference (RNAi) was used to explore the role of ABCG2 in body color deposition. The results showed that the ABCG2 sequence contained the conserved motif of Walker A, Walker B, Q-loop, d-loop, and H-loop. In tissues, ABCG2 was highly expressed in the epidermis of the four strains. During development stages, it was first expressed at the cleavage stage, then decreased at the gastrula stage, with the lowest expression at the pre-nauplius stage. From the metanauplius stage, its expression level was significantly upregulated until it reached the highest level at the membrane-zoea stage. WFISH showed that ABCG2 was first expressed at the cleavage stage in all four strains, and its distribution was similar from the cleavage stage to the before-zoea stage. The strongest positive signals were observed at the membrane-zoea stage, which was consistent with the qPCR results. Moreover, at the membrane-zoea stage, the positive signals of the four strains were mainly distributed in the compound eye and appendages. RNAi knockdown of ABCG2 encumbered the development of compound eye pigment cells (CEPCs) and erythrophores. It had effects on the expressions of other genes related to body color. These results suggest that ABCG2 is involved in the development of compound eye and the proliferation of erythrophores. This study provides new ideas for the cultivation of novel body colors in cherry shrimp at the molecular level.

Microinjection-based CRISPR/Cas9 mutagenesis in the decapoda crustaceans Neocaridina heteropoda and Eriocheir sinensis.

CRISPR/Cas9 technology has been applied to many arthropods. However, application of this technology to crustaceans remains limited because of the unique characteristics of embryos. Our group has developed a microinjection system to introduce the CRISPR/Cas9 system into Neocaridina heteropoda embryos (one-cell stage). Using the developed method, we mutated the target gene Nh-scarlet (N. heteropoda scarlet), which functions in eye development and pigmentation. The results showed that both eye color and shape were altered in individuals in which Nh-scarlet was knocked out. Furthermore, this system was also successfully applied to another decapod crustacean, Eriocheir sinensis. DNA sequencing revealed that the zoeae with red eyes had an edited version of Es-scarlet. This study provides a stable microinjection method for freshwater crustaceans, and will contribute to functional genomics studies in various decapods.

Effect of different substrates on growth and biochemical composition of the ornamental “red cherry” caridean shrimp, Neocaridina davidi (Atyidae)

The effect of different substrates on growth, sexual ratio, number of ovigerous females and survival of the red cherry shrimp, Neocaridina davidi, was analysed to enhance its culture. Recently hatched juvenile shrimps were exposed to 4 different substrates: Vesicularia sp., Ceratophyllum sp., Cabomba sp. and a green plastic net. Growth was analysed over 90 days with shrimps being weighed every 30 days. While maximum size was similar for all treatments, maximum relative growth rate and instantaneous growth was significantly greater and peaked earlier, respectively, in shrimps cultured with Vesicularia sp. Additionally, substrate had no effect on female and male final body weights or their biochemical composition (lipid and protein content). Sexual proportion was slightly biased towards males in all treatments. Survival was highest with Vesicularia sp. (90%) and similar among the remaining treatments (nearly 60%). Shrimps grown with Ceratophyllum sp. presented the lowest proportion of ovigerous females at 10% compared to 30–48% for other treatments. Overall, shrimp culture was significantly influenced by substrates. We hypothesize that Vesicularia sp. could enhance shrimp survival by supporting an environment free of pathogens; or that the periphytic community itself could provide benefits.

Long-Term Exposure of the Red Cherry Shrimp Neocaridina Davidi to Diclofenac: Impact on Survival, Growth, and Reproductive Potential

Long-Term Exposure of the Red Cherry Shrimp Neocaridina Davidi to Diclofenac: Impact on Survival, Growth, and Reproductive Potential

First report of microsporidians in the non-native shrimp Neocaridina davidi from a temperate European stream.

The release of ornamental pets outside their native range can directly or indirectly impact the recipient community, e.g. via the co-introduction of associated pathogens. However, studies on parasites associated with non-native species, in particular freshwater decapods, have focused mainly on a limited set of pathogens. Here we provide data for the first time on microsporidian parasites of the non-native ornamental shrimp Neocaridina davidi, collected in a stream in Germany. Furthermore, we confirm an ongoing range expansion of the warm-adapted N. davidi from thermally polluted colder water. In the investigated shrimps, the microsporidian parasite Enterocytozoon hepatopenaei and an unknown microsporidian isolate were detected, raising concerns about their transmission potential and pathogenicity on native crustacean species.

Brothers are better than nothing: first report of incestuous mating and inbreeding depression in a freshwater decapod crustacean

This study aimed at evaluating the effect of one generation of full-sibling mating on traits related to the fitness of the gregarious freshwater shrimp Neocaridina davidi, both under optimal and stressful (i.e. starvation) laboratory conditions. Females were maintained either with their brothers (Inbreeding treatment) or non-brothers (Outbreeding treatment), and the first and second broods were used to evaluate egg production and juvenile quality, respectively. The latter was analyzed in a 60-day period following hatching under optimal rearing conditions, and in a 20-day period following hatching under food deprivation conditions. All surviving females from both treatments mated and spawned, indicating that mating with brothers was as likely as mating with non-brothers. With respect to offspring production, inbreeding had no effect on fecundity and fertilization success, but negatively affected the number of hatched juveniles. These results suggest that egg loss was higher in inbred clutches, possibly due to lower embryonic survival. On the other hand, the effect of inbreeding on growth was absent for embryos and for juveniles under optimal rearing conditions, while it was significant for juveniles starved for 10 consecutive days following hatching. Inbreeding depression for survival was only detected in juveniles from stages S8-S9 under optimal rearing conditions. Overall, the present results show that N. davidi fitness decreases after one generation of full-sibling mating. The use of a potentially weak food deprivation protocol and/or the evaluation of only one inbred generation could explain the absence or subtle inbreeding depression for some of the evaluated traits. No evident relationship between life-history traits and the existence and magnitude of inbreeding was found when comparing our results with those previously reported in high-fecundity marine crustaceans and low-fecundity terrestrial crustaceans.

Can insecticide-free clean water regenerate the midgut epithelium of the freshwater shrimp after dimethoate treatment?

Insecticides such as dimethoate persist for a long time in freshwater environments, influencing the physiology of the animals inhabiting such environments. In aquatic organisms, toxic substances can enter the body through the epidermis and the digestive system. The midgut is part of this system in which intense processes constitute a barrier against the effects of toxic substances on the body. The aim of this study was to evaluate the toxic potential of dimethoate in the midgut epithelium of the freshwater shrimp Neocaridina davidi, emphasizing ultrastructural alterations. However, the additional and main purpose was to determine whether the midgut epithelium can regenerate after placing animals in insecticide-free clean water after various periods of exposure to dimethoate. N. davidi originates from Asia, but it has also been described in European rivers. This species is of particular interest among breeders worldwide due to its ease of breeding and reproduction. The animals were treated with dimethoate for 1, 2, and 3 weeks and then placed in clean water for 1, 2, and 3 weeks. The qualitative and quantitative analysis revealed different sensitivity of organs forming the midgut in freshwater crustaceans and the possibility for midgut regeneration after insecticide exposure. We concluded that different processes were triggered in the intestine and hepatopancreas to regenerate cells after damage, and mitochondria were the first organelles to respond to the appearance of a stressor in the living environment.