Abstract
Nepa cinerea is a common aquatic predator. It is widely distributed in various aquatic biotopes of the Palaearctic. Body size is an important trait that impacts the fitness and survival of animals and thus their evolution. Like most insects, N. cinerea males are smaller than females, but sexual size dimorphism (SSD) has not been investigated. We investigated the extent of SSD, the validity of Rensch's rule, and morphological differences between nine populations based on 51 morphological parameters. Females were found significantly and marginally significantly larger than males in all but one population. However, no difference in body length was found between the populations. Population had a significant effect on 12 traits for females and only on 5 for males, showing that females are more variable than males. Specifically, differences were found in the length of the second and third leg pairs. We did not find any support for the Rensch's rule. Nevertheless, female body size and SDI (sexual dimorphism index) were positively correlated. We suggest that fecundity selection accounts for female-biased SSD in N. cinerea.
Introduction
Female insects are usually larger than the males of the same species (Teder & Tammaru 2005, Stillwell et al. 2010). This phenomenon is called female-biased sexual size dimorphism (SSD). However, the selection effects responsible for differences in body size between the sexes are not well understood. Besides sexual selection, selection for survival, fecundity, development and growth, and their interactions, could account for the development of sex differences in body size (Webb & Freckleton 2007). Within a species, however, most of the morphological differences between populations can be explained by phenotypic plasticity (Stillwell et al. 2010).
As in many different ectotherm species (e.g. Blanckenhorn 2005), female body size and fecundity are positively correlated in insects (Honěk 1993, Preziosi et al. 1996). The fecundity selection hypothesis suggests that female-biased SSD occurs because selection favours larger-bodied, more fertile insect females over smaller-bodied ones. Strong fecundity selection generates directional selection for female body size or traits functionally related to fecundity (Scharf & Meiri 2013). This process is particularly relevant when larger female size provides a competitive advantage or increased protection against predation. There may be another reason for the difference in body size. Smaller males may be more mobile than larger ones. This behaviour may have a positive effect on mating success, as shown by Kelly et al. (2008) in a Cook Strait giant weta (Deinacrida rugosa) and by Boisseau et al. (2022) in a leaf insect (Phyllium philippinicum) population. As a result, the direction of selection will be in favour of smaller male individuals.
Phenotypic plasticity may contribute to female-biased body size differences in insects in several ways. If females are more sensitive or responsive to certain environmental conditions such as temperature or food resources, it could lead to female-biased body size differences through phenotypic plasticity (Stillwell & Fox 2007, Stillwell & Davidowitz 2010). Moreover, male and female reproductive strategies may have different trade-offs. If a larger body size provides advantages in terms of female fecundity or offspring survival, females may exhibit phenotypic plasticity to achieve a larger size (Darwin 1872). However, growing evidence suggests that female-biased SSD may also have evolved as a result of selection for smaller male body sizes (Pincheira-Donoso & Hunt 2017). On the other hand, males may also be smaller because they have to spend part of their available energy on mating competition with other males rather than on growth (Scharf et al. 2013).
According to Rensch's rule, for species where the female is the larger sex, the SSD will increase as the average body size decreases (Meiri & Liang 2021). However, the application of Rensch's rule to insects is ambiguous. In a large database study, Teder and Tammaru (2005) found that 81.6% of the insect species were female-biased and the SSD increased as the species' body size increased. This result contradicts the Rensch's rule. However, if we consider the latitudinal order, Rensch's rule is more often observed (Blanckenhorn et al. 2007).
The extent of the SSD varies not only between species, but also between populations within a species. The validity of Rensch's rule on the among population level is not clear. Some studies have confirmed the rule's validity for the water strider, Aquarius remigis (Abouheif & Fairbairn 1997), the grasshopper, Dichroplus pratensis (Bidau & Martí 2007) while others, for the dung beetle, Onthophagus babirussa (Toh et al. 2022), the red flour beetle, Tribolium castaneum (Martin et al. 2017), the freshwater isopod, Asellus aquaticus (Herczeg et al. 2023) have not. Fairbairn and Preziosi (1994) and Fairbairn (2005) showed that the body length, thorax, and abdomen of the Aquarius remigis, but not genital length, is consistent with the rule at the intraspecific level. Exploring the causes of intra-species differences is complicated by the fact that between different populations in sufficiently distant geographical locations, body size differences between males and females in different populations may even differ in their direction or may even show opposing patterns of SSD. North American populations of Sepsis punctum dung flies are female-biased, whereas European populations are male-biased (Puniamoorthy et al. 2012).
Like most insect species, body size in most water bugs (Nepomorpha) seems to be female-biased, according to the average or maximum-minimum body length data presented in several identification keys (e.g. Heckman 2011). Although this statement would appear to be correct looking at the raw data, there are a few cases where it is supported by statistical analysis. Such exceptions include the work of Nosil (2001) for Callicorixa vulnerata (Corixidae) and Svensson et al. (2000) for five Notonecta sp. (Notonectidae). Except for N. lutea, females of all other four backswimmer species and C. vulnerata are larger than males. Belostoma elegans sexes did not differ in length but in other nine morphological parameters (Iglesias et al. 2010). Female N. cinerea are also reported to be significantly larger than males (Bakonyi et al. 2016).
As for the morphological differences between populations within a species, there is very little data for water bugs. Nieser (1967) reports detailed data on the body size of females and males of four species of Buenoa (Notonectidae) from 2 to 4 populations. We have enough morphological data for as many as nine populations of N. cinerea (Bakonyi et al. 2016). To our knowledge, there are no other water bug species for which data from this many populations is available for an SSD study.
N. cinerea is a widely distributed species in the Palaearctic region (Polhemus et al. 1994, Polhemus 1995). Its main habitat is small to large streams but is also found in many areas of standing water (Hufnagel et al. 1998, Lock et al. 2013). It is a slow-moving, sit-and-wait predator which is usually found on the bottom. They prefer shady habitats with plenty of detritus (Peták et al. 2014). Most authors consider this species to be flightless (Hamilton 1931, Southwood & Leston 1959, Soós 1963, Nardi et al. 2002). Larsén (1970) found that the flight muscles of N. cinerea are very rarely fully developed. He does not report on whether individuals with fully developed flying muscles are actually able to fly. Only one paper reports that several individuals have been seen flying out of a pool in downtown of Hamburg in two consecutive years (Lempert 1997). Beyond that, only a few anecdotal observations (Wesenberg-Lund 1943, Larsen 1955) and/or oral reports of flying individuals are known (Gäde et al. 2007). Based on these observations, we believe that individuals capable of flight are unlikely to have been included in the present study. Because of its slow movement and inability to fly, it is reasonable to assume that even populations within a few kilometres distance are isolated from each other.
According to Medlock and Snow (2008) and Marin et al. (2019), this species can be used for biological control of mosquitoes. The relative size of predators plays an important role in the survival of mosquito larval populations (Russell et al. 2022). For three aquatic bug species (Appasus japonicus, Kirkaldyia deyrolli, and Laccotrephes japonensis; the latter is a close relative of N. cinerea), Nakazawa et al. (2013) found that predator-prey size ratios depended on predator size and species identity. This suggests that the effect of natural sexual selection on larger females may be worth investigating from a biological control perspective.
The study had the following objectives: (1) we wanted to investigate the variability of morphological characteristics of the two sexes in different populations to study the phenotypic plasticity of the species, (2) we evaluated the validity of Rensch's rule at the among-population level not only for body length but also for other morphological traits, (3) we also tested whether SSDs were more similar between spatially proximate than distant populations.
Methods
Individuals of Nepa cinerea L, 1758 were collected in the catchment area of Lake Balaton (Hungary) as described in Bakonyi et al. (2016) who provided detailed information on the collection sites, collection practice, preservation and morphological measurement methods of the animals. In this work, only sites where at least three individuals of each sex were collected are considered. We analysed 51 body size data from 48 females and 66 males. Morphological data of females and males collected from nine sampling sites (No 7, 9, 11, 12, 13, 15, 17, 21, 22) (Bakonyi et al. 2016) were analysed. The geographical location of the sampling sites is to be found in Fig. 1.
Location of the sampling sites in the catchment of Lake Balaton, Hungary. (Small-scale maps of the area and country are to be found in Bakonyi et al. (2016))
Citation: Animal Taxonomy and Ecology 70, 4; 10.1556/1777.2024.00027
The body length (from the frons to the anal siphon) and 50 morphological parameters were analysed (Fig. 2).
Position of the measurements. A: lengths of the coxa (1), trochanter (2), femur (3), tibia (4), tarsus (5) and claw (6) on all legs (forelegs do not bear claws), B: length (8) and width (12) of the scutellum, length (7) and width (11) of the prothorax, body length from the end of the scutellum to the anal siphon (9), distance between the eyes (10) C: width of the mesothorax (13), length of the anal siphon (14) D: distance of the length and width of the second (15–16) and first (17–18) pair of wings
Citation: Animal Taxonomy and Ecology 70, 4; 10.1556/1777.2024.00027
Body size data were log10 transformed to improve the normality of the data distribution when the female (on the X-axis) and male (on the Y-axis) parameters were regressed with the reduced major axis (RMA) procedure. Regression between body sizes and the sexual dimorphism index (SDI) and distance of sampling sites and body length-based SDI was tested with ordinary least squares (OLS) regression. The SDI is used to express sexual size dimorphism (SSD). Differences between 51 body measurements of females and males were obtained by discriminant analysis. Linear discriminant analysis was carried out using the “lda()” function from the MASS package (Venables & Ripley 2002) in R statistical software. Regression analyses, t-tests, chi2 test, Mood test, and ANOVA were performed with the PAST4 statistical software (Hammer et al. 2001). If the assumptions were not fulfilled, the Mann-Whitney test was carried out. Normality was checked with the Shapiro-Wilk test. Cohen's d was calculated with the lsr package (Navarro 2015). The coefficients of variation (CV) were also calculated for all morphological parameters and the SDI values for the nine collection sites. The significance between coefficients of variation was considered using the cvequality test (Marwick & Krishnamoorthy 2019). Both Cohen's d and significance between coefficients of variation were calculated with the R software (R Core Team 2022). Medians were compared with the Mood test. There are several methods to measure sexual dimorphism. In this study, the most commonly used procedure in ecological studies was used. Female and male sexual dimorphism index (SDI) was calculated according to Lovich and Gibbons (1992):
If males were larger than SDI = (size of largest sex/size of smallest sex) + 1 and
if females were larger than SDI = (size of largest sex/size of smallest sex) − 1.
Results
The body length of males was similar in the different populations (F: 1.627, P: 0.142), but females differed significantly (F: 3.679, P: 0.004). Females were significantly longer than males at six of the nine sites sampled (Table 1). In two cases, the difference was marginally significant. However, the effect sizes, which were significantly greater than 0.8, indicate that male and female body lengths also differed in these populations. In one population (No. 22) there was no difference in body length between the sexes. The SDI values based on body length varied between 0.116 and 0.181 in eight populations. In population No. 22, this value was lower by about two orders of magnitude (Table 1).
Female and male body length and sex difference index data for the nine collection sites. Data are given as average ± SD. NM: number of male animals, NF: number of female animals. As a rule of thumb, a Cohen's d value greater than 0.8 indicates a large effect size. CI: confidence interval of Cohen's d. Bold: significant difference between body length data. SDI: sexual dimorphism index. Site number: detailed description see Bakonyi et al. (2016)
| Site number | Male | NM | Female | NF | Cohen's d | P | SDI |
| 7 | 15.53 ± 0.75 | 6 | 18.33 ± 0.77 | 4 | −3.6 (−5.7; −1.42) | 0.014 | 0.181 |
| 9 | 15.41 ± 0.59 | 6 | 18.13 ± 0.84 | 7 | −3.69 (−5.53; −1.79) | <0.001 | 0.176 |
| 11 | 15.50 ± 0.50 | 8 | 17.30 ± 2.20 | 3 | −2.11 (−3.71; −0.43) | 0.027 | 0.116 |
| 12 | 15.69 ± 0.45 | 7 | 18.5 ± 0.41 | 7 | −6.59 (−9.37; −3.76) | <0.001 | 0.179 |
| 13 | 16.53 ± 1.73 | 5 | 18.51 ± 0.47 | 4 | −1.47 (−2.95; 0.08) | 0.064 | 0.120 |
| 15 | 16.39 ± 1.57 | 9 | 18.47 ± 0.39 | 3 | −1.48 (−2.9; 0.01) | 0.051 | 0.127 |
| 17 | 15.48 ± 0.42 | 5 | 18.18 ± 0.24 | 7 | −8.44 (−12.67; −4.18) | <0.001 | 0.174 |
| 21 | 15.15 ± 0.55 | 10 | 17.12 ± 1.59 | 5 | −1.99 (−3.28; −0.65) | 0.003 | 0.130 |
| 22 | 15.82 ± 0.81 | 3 | 15.92 ± 0.10 | 4 | −0.07 (−1.57; 1.43) | 0.928 | 0.006 |
| 15.72 ± 0.46 | 17.83 ± 0.88 | <0.001 | 0.134 ± 0.055 |
Considering all body part length parameters, female and male body sizes are separated by the first discriminant function (LD1), although there is some overlap between them (Fig. 3). According to the confusion matrix, 94.9% of the data are correctly classified. Moreover, the centroids of the body parameters of the two sexes (female: 2.1; male: −1.47) differ significantly (Wilks' lambda: 0.244, F: 2.571, P < 0.001). The results of the discriminant analysis by sex and population show that individuals of the same sex are morphologically largely similar to each other in all populations (Fig. 4). There are populations where the morphology of males and females is close together (Nos. 11, 13, 15, 21 and 22) and others where they are morphologically quite different (Nos. 7, 9, 12, 17). Given the relatively small number of animals found in each population and the limited data on habitat characteristics, we did not investigate further what might have caused these phenomena.
Histogram of the first discriminant function (LD1) data for N. cinerea males (group 1) and females (group 2), based on the body measurements. The data show that there are substantial morphological differences between the two sexes
Citation: Animal Taxonomy and Ecology 70, 4; 10.1556/1777.2024.00027
Discriminant plot of sex and population with convex hulls. F: female, M: male. The number of sampling sites corresponds to those shown in Fig. 1. Axes 1. and 2. explain 23.6% and 19.1% of the variances
Citation: Animal Taxonomy and Ecology 70, 4; 10.1556/1777.2024.00027
The body sizes of males and females differ between the nine populations in some other parameters. Population had a significant effect on 26 parameters in females and 16 in males (Table S1). When considering paired body parts, the width of the hind wing of females and the tarsus of the hind leg of males differed significantly between populations. In addition, females had significantly different pro- and mesothorax widths as well as hindwing widths according to the populations. So, the body size of females is more variable than that of males.
Similar to body length, CV values for the other body part lengths of the two sexes, except for five body parts, were not significantly different from each other (Table S2). However, a significant difference was found when the CV data of all body parts of the two sexes were compared (Mann-Whitney z: 4.2; P < 0.001). The total body size variation of females was almost twice that of males (mean rank: 31.4 and 19.1 for the females and males, respectively). The lowest and highest CV values of the SDI differed greatly by 139% (Fig. S1). Three body parts had high CVs both high right and left (right tarsus, left tarsus trochanter, left tarsus claw). Each of these body parts is associated with walking.
CV values were calculated for each body size. These were used to plot violin plots separately for females and males (Fig. 5). The overall shape of the violin plots differs for the sexes. It is clearly seen that the female data distribution is broader than that of the males. The data for the females are spread over a wide range. Females have a higher median CV value than males (0.059 and 0.041, respectively; chi2: 10.24, P: = 0.001).
Violin plots based on all CV data for the two sexes. The medians are significantly different (P = 0.001)
Citation: Animal Taxonomy and Ecology 70, 4; 10.1556/1777.2024.00027
Female and male body length regression is not significant (r2: 0.089; P: 0.435). For the 50 other body parts, there were only six cases in which a significant regression was found between the body part lengths of the two sexes (Table S3). In most cases, the slope was positive except for the trochanter of the right foreleg and the femur of the left hindleg. Among the paired organs, the midleg tarsus, while among the body size parameters, the length of the prothorax and the width of the scutellum gave a significant regression.
There is no difference between the mean body length of the animals found in each population and the SDI values (r2: 0.313; P: 0.117). No correlation was found between male body size and corresponding SDI values (r2: 0.058; P: 0.531). On the other hand, SDI increased significantly with increasing body length in females (r2: 0.069; P: 0.004) (Fig. 6.). A similar overall picture was found for all the other parts of the body. In females, 37 out of the 50 comparisons showed a significant increase. In contrast, only four significant increases occurred in males (Table S4).
Correlation of SDI with body length. Females: point (●), males: triangle (▲). Grey band: 95% confidence interval
Citation: Animal Taxonomy and Ecology 70, 4; 10.1556/1777.2024.00027
There was no significant regression between the distance of sampling sites and body length-based SDIs (r2: 0.058; P: 0.616). Even for sampling sites closest to each other, the SDI could differ considerably. On the other hand, similar SDIs were found for sampling sites very far apart (Fig.7). Consequently, the SSD was not related to distance between populations. The same results were obtained for all other body parameters because in none of the cases was a correlation found between the distance between the sampling sites and SDI (Table S5).
The distance between collection sites and the body length SDI. Distance: the distance between the two nearest sampling sites. Grey band: 95% confidence interval. (Out of the nine sampling sites, six pairs could be matched, as some sites participated in more than one pairing, see Table S5)
Citation: Animal Taxonomy and Ecology 70, 4; 10.1556/1777.2024.00027
Discussion
The among-population morphological diversity of insect populations is an important issue in evolution and ecology research, but it has been little studied to date (Pincheira-Donoso & Hunt 2017, Gentile et al. 2021). There is little research on water bugs, although as top predators they play an important role in aquatic food webs (Papacek 2001). We examined the body size parameters of N. cinerea and found that the sexes were remarkably different from each other. Clear sexual asymmetry in body size was found as females were more robust than males. Similarly, a review article by Teder and Tammaru (2005) found 81.6% of species to be female-biased. The female body length and several other female body size parameters differed significantly between populations. The differences are caused by the need for animals to obtain food and fight predators under different abiotic conditions (Chown & Gaston 2010). As far as water bugs are concerned, Nosil (2001) obtained results consistent with the general trend for C. vulnerata. However, the females of B. elegans were not longer than the males (Iglesias et al. 2010), showing that female-biased SSD is not general in Nepomorpha.
Overall, it can be concluded that the body size of N. cinerea females is much more variable than that of males, as indicated by the significantly higher CV of the body measurements. A greater morphological variance of females than males is common among insects (Stillwell et al. 2010). As no background data are available for our species, the cause of this variability is unknown. The explanation may be the widely accepted concept that in female-biased insect species, the relationship between female body size and fitness is a consequence of the fecundity selection (fecundity advantage hypothesis) (Fairbairn & Preziosi 1994). This hypothesis predicts that selection favours larger female size because of their higher lifetime reproductive success (Honěk 1993, Preziosi et al. 1996, but see Pincheira-Donoso & Hunt 2017).
Furthermore, for the Heteroptera species several physiological and environmental factors, rather than larval resources may be responsible for the greater morphological diversity of females (Honěk 1993, Rohner et al. 2018). Body size variations in this taxon is usually a result of the environmentally cued plasticity. Therefore, it is likely that the morphological differences observed between females from different populations are determined by the temperature (Berger et al. 2008, but see Hu et al. 2010), the growth rate, and the quality and quantity of food sources (Stillwell & Fox 2007, Stillwell et al. 2007). There is usually a strong directional selection towards larger body size and thus greater fecundity in females (Kelly et al. 2008). However, virtually nothing is known about how the above-mentioned background variables affect N. cinerea morphology.
Little is known about the selective forces that determine the body size of insect males. Boisseau et al. (2022) and Kelly et al. (2008) found that small, more mobile males are at an advantage in the competition for females in scramble competition mating systems. In two species of black scavenger flies (Diptera: Sepsidae), Sepsis punctum and S. neocynipsea, the intensity of sexual selection on size was stronger in males than in females. An important aspect is that male-biased populations were studied (Rohner et al. 2016, 2018). In the case of female-biased species smaller males are often more successful at mating than larger males. For small males less energy is required to find food and more is left over for mating (Boisseau et al. 2022) or they are favoured in scramble competition due to their greater mobility (Blanckenhorn 2005).
Rensch's rule states that for female-biased taxa, the SSD at the interspecies level will increase as the mean size decreases (Rensch 1950). The rule has also been tested at the among-population level in insects, but inconsistent results were obtained (Blanckenhorn et al. 2007, Martin et al. 2017). For example, the rule was confirmed for the water strider, Aquarius remiges (Fairbairn & Preziosi 1994), and inverse Rensch's rule was found to be valid for the grasshopper, Dichroplus pratensis (Bidau & Martí 2007). No confirmation was found in laboratory studies of 21 populations of the beetle species Tribolium castaneum (Martin et al. 2017), the beetle, Acanthoscelides macrophthalmus (Rossi and Haga 2019), and the isopod, Asellus aquaticus (Herczeg et al. 2023). Furthermore, Martin et al. (2017) concluded that Rensch's rule usually does not hold for female-biased insect species. As body length regards, our results support this claim. However, there are exceptions depending on the body part we were looking at. Alike (Iglesias et al. 2010) finding in five Belostoma and one Lethocerus species (all genera are Nepomorpha), we found also that SSD was dependent on which morphological feature was examined. Unfortunately, we cannot address why tarsus and prothorax length and scutellum width follow Rensch's rule. A plausible explanation would require knowledge of the sex differences in larval diet (Teder et al. 2022, Seifert 2024), nutritional needs (Chelini et al. 2019), development time of the sexes (Teder et al. 2021), and survival in different habitats (Teder & Tammaru 2005).
Moreover, according to Teder and Tammaru (2005) several interspecific studies for female-biased species show that as the average body size of both sexes increases, SSD also increases. For Heteroptera species, this phenomenon is quite pronounced. Our results do not support this claim. However, if we regress the length of the body parts of the sexes separately on the SDI, it becomes clear that for males there is a relationship between a trait and the SDI in only a few cases, but for females in the majority of cases. This suggests that being more sensitive to environmental conditions the variability of females is responsible for the development of SSD in N. cinerea. In insects, sexes often differ in their responses to environmental changes such as food limitation or quality and larval density. Frequently, the larger sex - typically females - shows stronger response (Cordeschi et al. 2024).
The degree of among-population SSD is highly variable between insect species (Teder & Tammaru 2005). It is, however, depends on the spatial scale at which the differences are examined. At the continental scale differences may occur, but not necessarily. Although related to species, the SSD for Sepsis cynipsea but not for S. neocynipsea fly was inverse at the continental scale (Rohner et al. 2016). The cabbage beetle Colaphellus bowringi body weight SSD was associated with latitude (Tang et al. 2017). Sukhodolskaya et al. (2021) found an effect of altitude on Pterostichus montanus (Carabidae) SSD values.
We did not find such results probably because our sampling area was not large enough to detect geographical scale effects (data of N. cinerea populations was collected in an area of about 3,000 km2 in this study). However, latitudinal differences may be important, because in Italy N. cinerea individuals became smaller from north to south (Tamanini 1973).
The differential equilibrium hypothesis predicts that females are under fecundity selection and sexual selection acts on males for increased body size in insects (Blanckenhorn 2000, Rohner et al. 2016). Our results suggest that the degree of the SSD in N. cinerea at the among-population level is a result of fecundity, but not sexual selection. As examined populations have been isolated from each other due to the poor migration ability of the animals, ecological and genetic selection effects can be strong. In the case of females, selection was at work, resulting in higher variability in body size than males. This is why we found significant differences in several body measurements of the females, but very few in males. However, further studies are needed to determine whether selection affects fertility or female body size. In contrast, small differences in body size were found for males that may indicate a lack of male-directed selection.
In conclusion, body length is not the best morphological trait in N. cinerea among-population SSD studies. Measurements connected to legs seem to be more informative about the selection forces which create morphological differences in sexes. The significantly greater morphological diversity of females than males suggests that selection forces act primarily on females. To identify the cause of SSD it is necessary to determine sex-specific growth rate (or development time), the body size-dependent female fecundity (number and quality of offspring), mate choice behavior (factors influencing mate choice), and sexual bimaturism (females and males will be sexually mature at different times). If we want to use N. cinerea for biological control of mosquitoes, the causes of SSD need to be better understood. After that, suitable populations can be selected for successful population regulation of mosquitos.
Acknowledgements
We thank Ms Eszter Peták for his contribution to this work. She collected and measured the animals. Our manuscript has greatly benefitted from comments provided by two anonymous reviewers. We would like to thank Borbála Szabó (University Bremen) for her help in answering statistical questions. This work was supported by the Research Excellent Programme 2024 (SA) and the Flagship Research Groups Programme of the Hungarian University of Agriculture and Life Sciences.
Supplementary materials
Supplementary data to this article can be found online at https://doi.org/10.1556/1777.2024.00027.
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