The influence of age on male bank voles’ reproductive tract development, epididymal sperm quantity and functional activity was investigated. Experiments were carried out on male bank voles aged 1.5 to 15 months (n=10 each in 8 age groups). The developmental stage of the reproductive tract was assessed by the weight of testes, seminal vesicles and coagulation glands. In each age group the number of epididymal sperm and their functional activity were examined. Epididymal sperm functional activity was assessed by motility, viability, maturity, head morphology and integrity of the sperm tail membrane. Ageing males were heavier than pre-pubertal and mature ones. Male age also affected the testes, seminal vesicles and coagulation gland development. The heaviest accessory sex glands were noted in 3-month-old males and the lightest in pre-pubertal (1.5-month-old) and older (12- and 15-month-old) males. Sperm counts were significantly higher in 3-, 4- and 5-month-old males than in pre-pubertal and old males. Generally, adult males aged 3- and 4- months, produced sperm of better functional activity. In conclusion, the best male reproductive capacity is found in bank voles of 3 to 4 months of age.
{"title":"Reproductive capacity of male bank voles (Myodes glareolus Schreber, 1780) – age-dependent changes in functional activity of epididymal sperm","authors":"M. Kruczek, J. Styrna, J. Kapusta","doi":"10.26496/bjz.2013.129","DOIUrl":"https://doi.org/10.26496/bjz.2013.129","url":null,"abstract":"The influence of age on male bank voles’ reproductive tract development, epididymal sperm quantity and functional activity was investigated. Experiments were carried out on male bank voles aged 1.5 to 15 months (n=10 each in 8 age groups). The developmental stage of the reproductive tract was assessed by the weight of testes, seminal vesicles and coagulation glands. In each age group the number of epididymal sperm and their functional activity were examined. Epididymal sperm functional activity was assessed by motility, viability, maturity, head morphology and integrity of the sperm tail membrane. Ageing males were heavier than pre-pubertal and mature ones. Male age also affected the testes, seminal vesicles and coagulation gland development. The heaviest accessory sex glands were noted in 3-month-old males and the lightest in pre-pubertal (1.5-month-old) and older (12- and 15-month-old) males. Sperm counts were significantly higher in 3-, 4- and 5-month-old males than in pre-pubertal and old males. Generally, adult males aged 3- and 4- months, produced sperm of better functional activity. In conclusion, the best male reproductive capacity is found in bank voles of 3 to 4 months of age.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140247116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Vanschoenwinkel, L. Brendonck, Tom Pinceel, Pascal Dupriez, A. Waterkeyn
Fairy shrimps (Crustacea, Anostraca) are specialized inhabitants of inland water bodies that periodically dry or freeze over. Here we report the first observation since 1997 of a member of this basal crustacean order in Belgium and the first sighting of the species Branchipus schaefferi Fischer, 1834 since 1930. Nineteen populations were found in a restricted area located 55 km SE of Brussels in the Province of Hainaut. Based on a field survey, we discuss the habitat characteristics of these populations. We discuss also the distribution and habitat requirements of the species based on literature and formulate a number of guidelines for the conservation of this species as well as other large branchiopods in densely settled areas with intensive agriculture such as Belgium. Finally, we formulate a number of likely explanations for the lack of recent observations of these organisms in Western Europe and in Belgium.
{"title":"Rediscovery of Branchipus schaefferi (Branchiopoda: Anostraca) in Belgium - notes on habitat requirements and conservation management","authors":"B. Vanschoenwinkel, L. Brendonck, Tom Pinceel, Pascal Dupriez, A. Waterkeyn","doi":"10.26496/bjz.2013.119","DOIUrl":"https://doi.org/10.26496/bjz.2013.119","url":null,"abstract":"Fairy shrimps (Crustacea, Anostraca) are specialized inhabitants of inland water bodies that \u0000periodically dry or freeze over. Here we report the first observation since 1997 of a member of this basal crustacean order in Belgium and the first sighting of the species Branchipus schaefferi Fischer, 1834 since 1930. Nineteen populations were found in a restricted area located 55 km SE of Brussels in the Province of Hainaut. Based on a field survey, we discuss the habitat characteristics of these populations. We discuss also the distribution and habitat requirements of the species based on literature and formulate a number of guidelines for the conservation of this species as well as other large branchiopods in densely settled areas with intensive agriculture such as Belgium. Finally, we formulate a number of likely explanations for the lack of recent observations of these organisms in Western Europe and in Belgium.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140247160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Understanding the ecology of bioindicators such as ostracods is essential in order to reconstruct past environmental and climate change from analysis of fossil assemblages preserved in lake sediment cores. Knowledge of the ecology of ancient Lake Ohrid’s ostracod fauna is very limited and open to debate. In advance of the Ohrid ICDP-Drilling project, which has potential to generate high-resolution long-term paleoenvironmental data of global importance in paleoclimate research, we sampled Lake Ohrid and a wide range of habitat types in its surroundings to assess 1) the composition of ostracod assemblages in lakes, springs, streams, and short-lived seasonal water bodies, 2) the geographical distribution of ostracods, and 3) the ecological characteristics of individual ostracod species. In total, 40 species were collected alive, and seven species were preserved as valves and empty carapaces. Of the 40 ostracod species, twelve were endemic to Lake Ohrid. The most common genus in the lake was Candona, represented by 13 living species, followed by Paralimnocythere, represented by five living species. The most frequent species was Cypria obliqua. Species with distinct distributions included Heterocypris incongruens, Candonopsis kingsleii, and Cypria lacustris. The most common species in shallow, flooded areas was H. incongruens, and the most prominent species in ditches was C. kingsleii. C. lacustris was widely distributed in channels, springs, lakes, and rivers. Statistical analyses were performed on a “Lake Ohrid” dataset, comprising the subset of samples from Lake Ohrid alone, and an “entire” dataset comprising all samples collected. The unweighted pair group mean average (UPGMA) clustering was mainly controlled by species-specific depth preferences. Canonical Correspondence Analysis (CCA) with forward selection identified water depth, water temperature, and pH as variables that best explained the ostracod distribution in Lake Ohrid. The lack of significance of conductivity and dissolved oxygen in CCA of Ohrid data highlight the uniformity across the lake of the well-mixed waters. In the entire area, CCA revealed that ostracod distribution was best explained by water depth, salinity, conductivity, pH, and dissolved oxygen. Salinity was probably selected by CCA due to the presence of Eucypris virens and Bradleystrandesia reticulata in short-lived seasonal water bodies. Water depth is an important, although indirect, influence on ostracod species distribution, which is probably associated with other factors such as sediment texture and food supply. Some species appeared to be indicators for multiple environmental variables, such as lake level and water temperature.
{"title":"Autecology of the extant ostracod fauna of Lake Ohrid and adjacent waters - a key to paleoenvironmental reconstruction","authors":"Julia Lorenschat, A. Schwalb","doi":"10.26496/bjz.2013.123","DOIUrl":"https://doi.org/10.26496/bjz.2013.123","url":null,"abstract":"Understanding the ecology of bioindicators such as ostracods is essential in order to reconstruct past environmental and climate change from analysis of fossil assemblages preserved in lake sediment cores. Knowledge of the ecology of ancient Lake Ohrid’s ostracod fauna is very limited and open to debate. In advance of the Ohrid ICDP-Drilling project, which has potential to generate high-resolution long-term paleoenvironmental data of global importance in paleoclimate research, we sampled Lake Ohrid and a wide range of habitat types in its surroundings to assess 1) the composition of ostracod assemblages in lakes, springs, streams, and short-lived seasonal water bodies, 2) the geographical distribution of ostracods, and 3) the ecological characteristics of individual ostracod species. In total, 40 species were collected alive, and seven species were preserved as valves and empty carapaces. Of the 40 ostracod species, twelve were endemic to Lake Ohrid. The most common genus in the lake was Candona, represented by 13 living species, followed by Paralimnocythere, represented by five living species. The most frequent species was Cypria obliqua. Species with distinct distributions included Heterocypris incongruens, Candonopsis kingsleii, and Cypria lacustris. The most common species in shallow, flooded areas was H. incongruens, and the most prominent species in ditches was C. kingsleii. C. lacustris was widely distributed in channels, springs, lakes, and rivers. Statistical analyses were performed on a “Lake Ohrid” dataset, comprising the subset of samples from Lake Ohrid alone, and an “entire” dataset comprising all samples collected. The unweighted pair group mean average (UPGMA) clustering was mainly controlled by species-specific depth preferences. Canonical Correspondence Analysis (CCA) with forward selection identified water depth, water temperature, and pH as variables that best explained the ostracod distribution in Lake Ohrid. The lack of significance of conductivity and dissolved oxygen in CCA of Ohrid data highlight the uniformity across the lake of the well-mixed waters. In the entire area, CCA revealed that ostracod distribution was best explained by water depth, salinity, conductivity, pH, and dissolved oxygen. Salinity was probably selected by CCA due to the presence of Eucypris virens and Bradleystrandesia reticulata in short-lived seasonal water bodies. Water depth is an important, although indirect, influence on ostracod species distribution, which is probably associated with other factors such as sediment texture and food supply. Some species appeared to be indicators for multiple environmental variables, such as lake level and water temperature.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140246239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. V. D. Broecke, J. Vanfleteren, K. Martens, I. Schön
Ostracoda or mussel-shrimps are small, bivalved Crustacea. Because of their excellent fossil record and their broad variety of reproductive modes, ostracods are of great interest as a model group in ecological and evolutionary research. Here, we investigated damage and repair from one of the most important biological mutagens, namely UVB radiation, in the putative ancient asexual ostracod Darwinula stevensoni from Belgium. We applied three different methods: the Polymerase Inhibition (PI) assay, Enzyme-Linked Immuno Sorbent Assay (ELISA) and dot blot. All three techniques were unsuccessful in quantifying UVB damage in D. stevensoni. Previous experiments have revealed that the valves of D. stevensoni provide an average UVB protection of approximate 60%. Thus, UVB damage could be too little to make quantitative experiments work. Additionally, variation between individual ostracods due to season and age most likely contributed further to the failure of the three used experimental approaches to quantify damage. In a second experiment, we investigated the influence of temperature on survival of D. stevensoni during UVB exposure. The estimated relative lethal UVB dose at 4°C was with 50 kJ/m2, significantly lower than at room temperature, with 130 kJ/m2. This could either indicate lack of adaptation to low temperatures and/or the presence of metabolic processes active at room temperature protecting against UVB damage in D. stevensoni. The latter possibility could also explain why the estimated relative lethal UVB dose of D. stevensoni is similar to that of other non-marine ostracods where valves provide around 80% protection, despite the valves of D. stevensoni providing less protection. If such metabolic processes can repair UVB damage quickly, this may provide an alternative explanation why we could not quantify UVB damage in D. stevensoni.
介壳虫或贻贝虾是小型双壳甲壳动物。由于其出色的化石记录和多种多样的繁殖模式，梭形纲动物作为生态学和进化研究中的模式类群具有极大的兴趣。在这里，我们研究了来自比利时的推定古老无性介壳动物 Darwinula stevensoni 最重要的生物诱变剂之一--紫外线辐射的损伤和修复。我们采用了三种不同的方法：聚合酶抑制法（PI）、酶联免疫吸附法（ELISA）和点印迹法。所有这三种技术都不能成功地量化紫外线对 D. stevensoni 的伤害。以前的实验表明，史蒂文索尼虫瓣膜对紫外线的平均防护率约为 60%。因此，紫外线伤害可能太小，无法进行定量实验。此外，由于季节和年龄的不同，个体间的差异很可能进一步导致这三种实验方法无法量化损害。在第二个实验中，我们研究了在紫外线照射期间温度对 D. stevensoni 存活率的影响。据估计，4°C时紫外线的相对致死剂量为50千焦/平方米，明显低于室温下的130千焦/平方米。这可能表明史蒂文森冬虫夏草缺乏对低温的适应性，也可能表明在室温下活跃的新陈代谢过程可以保护史蒂文森冬虫夏草免受紫外线的伤害。后一种可能性也可以解释为什么D. stevensoni的估计相对致死紫外线剂量与其他非海洋梭形纲动物相似，后者的瓣膜可提供约80%的保护，而D. stevensoni的瓣膜提供的保护较少。如果这种新陈代谢过程可以快速修复紫外线的伤害，这可能是我们无法量化史蒂文梭鱼紫外线伤害的另一种解释。
{"title":"Hurdles in investigating UVB damage in the putative ancient asexual Darwinula stevensoni (Ostracoda, Crustacea)","authors":"L. V. D. Broecke, J. Vanfleteren, K. Martens, I. Schön","doi":"10.26496/bjz.2013.131","DOIUrl":"https://doi.org/10.26496/bjz.2013.131","url":null,"abstract":"Ostracoda or mussel-shrimps are small, bivalved Crustacea. Because of their excellent fossil record and their broad variety of reproductive modes, ostracods are of great interest as a model group in ecological and evolutionary research. Here, we investigated damage and repair from one of the most important biological mutagens, namely UVB radiation, in the putative ancient asexual ostracod Darwinula stevensoni from Belgium. We applied three different methods: the Polymerase Inhibition (PI) assay, Enzyme-Linked Immuno Sorbent Assay (ELISA) and dot blot. All three techniques were unsuccessful in quantifying UVB damage in D. stevensoni. Previous experiments have revealed that the valves of D. stevensoni provide an average UVB protection of approximate 60%. Thus, UVB damage could be too little to make quantitative experiments work. Additionally, variation between individual ostracods due to season and age most likely contributed further to the failure of the three used experimental approaches to quantify damage. In a second experiment, we investigated the influence of temperature on survival of D. stevensoni during UVB exposure. The estimated relative lethal UVB dose at 4°C was with 50 kJ/m2, significantly lower than at room temperature, with 130 kJ/m2. This could either indicate lack of adaptation to low temperatures and/or the presence of metabolic processes active at room temperature protecting against UVB damage in D. stevensoni. The latter possibility could also explain why the estimated relative lethal UVB dose of D. stevensoni is similar to that of other non-marine ostracods where valves provide around 80% protection, despite the valves of D. stevensoni providing less protection. If such metabolic processes can repair UVB damage quickly, this may provide an alternative explanation why we could not quantify UVB damage in D. stevensoni.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140247673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We studied the thermal tolerances of Odontophrynus occidentalis during the dry and wet seasons of the Monte Desert in San Juan Province, Argentina. This toad had differences in CTmax between dry and wet seasons, with CTmax values being greater in the wet season (Austral summer). Operative temperature, body temperature, and environmental maximal temperature were related to CTmax suggesting seasonal acclimatization in O. occidentalis. Additionally, the CTmax recorded for O. occidentalis was 36.1ºC, and the maximum ambient temperature measured during the toads’ activity time was 37ºC. The CTmin of O. occidentalis was 4.1ºC while the minimum environmental temperature recorded was 7.2 ºC. The wide tolerance range observed and the relationship between tolerance limits and the environmental extremes indicate that seasonal acclimatization is an effective mechanism by which toads can raise their thermal tolerance. This is a highly relevant adaptation allowing them to survive in the challenging conditions of the Monte Desert.
我们研究了阿根廷圣胡安省蒙特沙漠蟾蜍（Odontophrynus occidentalis）在旱季和雨季的热耐受性。这种蟾蜍在旱季和雨季的 CTmax 值存在差异，雨季（澳大利亚夏季）的 CTmax 值更大。操作温度、体温和环境最高温度都与 CTmax 有关，这表明 O. occidentalis 具有季节适应性。此外，O. occidentalis 的最高 CT 值为 36.1ºC，在蟾蜍活动期间测得的最高环境温度为 37ºC。O. occidentalis 的 CTmin 为 4.1ºC，而记录到的最低环境温度为 7.2 ºC。观察到的广泛耐受范围以及耐受极限与极端环境之间的关系表明，季节性适应是蟾蜍提高热耐受性的一种有效机制。这是一种非常重要的适应能力，使它们能够在蒙特沙漠充满挑战的条件下生存。
{"title":"Seasonal Changes in the thermal tolerances of Odontophrynus occidentalis (Berg, 1896) (Anura: Cycloramphidae)","authors":"E. Sanabria, L. Quiroga, A. Martino","doi":"10.26496/bjz.2013.121","DOIUrl":"https://doi.org/10.26496/bjz.2013.121","url":null,"abstract":"We studied the thermal tolerances of Odontophrynus occidentalis during the dry and wet seasons of the Monte Desert in San Juan Province, Argentina. This toad had differences in CTmax between dry and wet seasons, with CTmax values being greater in the wet season (Austral summer). Operative temperature, body temperature, and environmental maximal temperature were related to CTmax suggesting seasonal acclimatization in O. occidentalis. Additionally, the CTmax recorded for O. occidentalis was 36.1ºC, and the maximum ambient temperature measured during the toads’ activity time was 37ºC. The CTmin of O. occidentalis was 4.1ºC while the minimum environmental temperature recorded was 7.2 ºC. The wide tolerance range observed and the relationship between tolerance limits and the environmental extremes indicate that seasonal acclimatization is an effective mechanism by which toads can raise their thermal tolerance. This is a highly relevant adaptation allowing them to survive in the challenging conditions of the Monte Desert.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140245210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Primitive horses are quite often kept in nature reserves with access to the forest, which they sometimes penetrate to use the vegetation. Horses, as grazers, use specific foraging and anti-predator strategies that differ from typical browsers. The aim of the study was to assess the factors influencing the pattern of forest use by Bilgoraj horses. We hypothesized that the essential factors influencing their pattern of foraging are: browse abundance, distance to pasture, and openness of the habitat. Data were collected at the Biłgoraj Horse-Breeding Centre near Janów Lubelski, Poland. The horses browsed significantly more on woody vegetation in parts of the forest more exposed to sunlight and more abundant in browse material (especially containing preferred species). Distance to the main pasture had a significant effect upon browsing intensity only when an interaction with the abundance of preferred browse was considered.
{"title":"Selective use of forest habitat by Biłgoraj horses","authors":"Daniel Klich, Magdalena Grudzień","doi":"10.26496/bjz.2013.132","DOIUrl":"https://doi.org/10.26496/bjz.2013.132","url":null,"abstract":"Primitive horses are quite often kept in nature reserves with access to the forest, which they sometimes penetrate to use the vegetation. Horses, as grazers, use specific foraging and anti-predator strategies that differ from typical browsers. The aim of the study was to assess the factors influencing the pattern of forest use by Bilgoraj horses. We hypothesized that the essential factors influencing their pattern of foraging are: browse abundance, distance to pasture, and openness of the habitat. Data were collected at the Biłgoraj Horse-Breeding Centre near Janów Lubelski, Poland. The horses browsed significantly more on woody vegetation in parts of the forest more exposed to sunlight and more abundant in browse material (especially containing preferred species). Distance to the main pasture had a significant effect upon browsing intensity only when an interaction with the abundance of preferred browse was considered.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140247419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Olivier, N. Vandewalle, Q. Mauguit, É. Parmentier
Swimming has been investigated in multiple species, but few studies consider the establishment of swimming through ontogeny. This study describes the establishment of cyclical swimming in Dicentrachus labrax, a marine fish from cold, temperate waters. The data were compared with results from previous studies on two subtropical freshwater catfish species (Clarias gariepinus and Corydoras aeneus). The three species have different modes of locomotion each during their adult stage (anguilliform, subacarangiform and carangiform). The swimming of Dicentrarchus labrax was recorded with a high-speed video camera (500 fps) from 0 to 288 hours and from 960 to 2496 hours post-hatching. Three indices, i.e. coefficient of determination (r²), coefficient of variation (CV), and Strouhal number (St), were used to investigate the establishment and efficiency of swimming. Important differences in the timing of swimming establishment were observed between the seabass and the two catfish species. The two catfish species display a sine-shaped swimming mode immediately or soon after hatching, and the efficiency of movement substantially improves during the first days of life. For seabass, however, establishment of swimming is slower during the same developmental period. These differences may be related to a faster developmental rate in the catfishes that allows them to swim rapidly in an intermediate regime flow and to develop the required morphology to establish efficient movements earlier.
{"title":"Kinematic analysis of swimming ontogeny in seabass (Dicentrarchus labrax)","authors":"D. Olivier, N. Vandewalle, Q. Mauguit, É. Parmentier","doi":"10.26496/bjz.2013.125","DOIUrl":"https://doi.org/10.26496/bjz.2013.125","url":null,"abstract":"Swimming has been investigated in multiple species, but few studies consider the establishment of swimming through ontogeny. This study describes the establishment of cyclical swimming in Dicentrachus labrax, a marine fish from cold, temperate waters. The data were compared with results from previous studies on two subtropical freshwater catfish species (Clarias gariepinus and Corydoras aeneus). The three species have different modes of locomotion each during their adult stage (anguilliform, subacarangiform and carangiform). The swimming of Dicentrarchus labrax was recorded with a high-speed video camera (500 fps) from 0 to 288 hours and from 960 to 2496 hours post-hatching. Three indices, i.e. coefficient of determination (r²), coefficient of variation (CV), and Strouhal number (St), were used to investigate the establishment and efficiency of swimming. Important differences in the timing of swimming establishment were observed between the seabass and the two catfish species. The two catfish species display a sine-shaped swimming mode immediately or soon after hatching, and the efficiency of movement substantially improves during the first days of life. For seabass, however, establishment of swimming is slower during the same developmental period. These differences may be related to a faster developmental rate in the catfishes that allows them to swim rapidly in an intermediate regime flow and to develop the required morphology to establish efficient movements earlier.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140247999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. L. Schoeman, N. Kmentová, M. Vanhove, L. D. du Preez
The African Clawed Frog Xenopus laevis, a global invader, exhibits a marked phylogeographic divergence among native populations in southern Africa, which seems to enhance its invasive potential. The polystomatid flatworm, Protopolystoma xenopodis, is the frog’s most frequently co-introduced metazoan parasite. In an integrative approach, we utilised morphometrics and molecular markers to assess variation in P. xenopodis in its native range. We measured twelve key morphological characters from 23 flatworms and compared these statistically between flatworms collected from the northern- and southernmost distribution in South Africa. Phylogenetic analyses were based on three concatenated markers, namely 28S and 12S rDNA and COX1, from six flatworms. The combination of five morphological characters, which involve egg size, gut morphology and size of the attachment hooks, differentiated northern and southern populations of P. xenopodis. The multilocus phylogenetic analyses showed a cluster of northern P. xenopodis and two southern lineages with more basal positioning. These findings demonstrate a relatively high level of intraspecific variation in P. xenopodis in its native range. The presented intraspecific variation of P. xenopodis could be potentially informative to trace geographic origin in its non-native range.
非洲爪蛙（Xenopus laevis）是一种全球入侵者，在非洲南部的原生种群中表现出明显的系统地理分化，这似乎增强了它的入侵潜力。蛙类最常见的共同引进寄生虫是扁形多囊虫（Protopolystoma xenopodis）。我们采用了一种综合方法，利用形态计量学和分子标记来评估 P. xenopodis 在其原生地的变异。我们测量了 23 种扁形虫的 12 个关键形态特征，并对从南非最北和最南分布区采集的扁形虫进行了统计比较。系统发育分析是基于来自六种扁形虫的 28S 和 12S rDNA 以及 COX1 这三个联合标记进行的。五种形态特征（包括卵的大小、肠道形态和附钩的大小）的组合区分了 P. xenopodis 的北部和南部种群。多焦点系统进化分析表明，P. xenopodis 在北方有一个聚类，在南方有两个定位较低的品系。这些研究结果表明，P. xenopodis 在其原产地的种内变异水平相对较高。所呈现的 P. xenopodis 种内变异可能有助于追踪其非原生地的地理起源。
{"title":"Intraspecific morphological and genetic variation in South African populations of a polystomatid flatworm parasite","authors":"A. L. Schoeman, N. Kmentová, M. Vanhove, L. D. du Preez","doi":"10.26496/bjz.2024.118","DOIUrl":"https://doi.org/10.26496/bjz.2024.118","url":null,"abstract":"The African Clawed Frog Xenopus laevis, a global invader, exhibits a marked phylogeographic divergence among native populations in southern Africa, which seems to enhance its invasive potential. The polystomatid flatworm, Protopolystoma xenopodis, is the frog’s most frequently co-introduced metazoan parasite. In an integrative approach, we utilised morphometrics and molecular markers to assess variation in P. xenopodis in its native range. We measured twelve key morphological characters from 23 flatworms and compared these statistically between flatworms collected from the northern- and southernmost distribution in South Africa. Phylogenetic analyses were based on three concatenated markers, namely 28S and 12S rDNA and COX1, from six flatworms. The combination of five morphological characters, which involve egg size, gut morphology and size of the attachment hooks, differentiated northern and southern populations of P. xenopodis. The multilocus phylogenetic analyses showed a cluster of northern P. xenopodis and two southern lineages with more basal positioning. These findings demonstrate a relatively high level of intraspecific variation in P. xenopodis in its native range. The presented intraspecific variation of P. xenopodis could be potentially informative to trace geographic origin in its non-native range.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139833731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. L. Schoeman, N. Kmentová, M. Vanhove, L. D. du Preez
The African Clawed Frog Xenopus laevis, a global invader, exhibits a marked phylogeographic divergence among native populations in southern Africa, which seems to enhance its invasive potential. The polystomatid flatworm, Protopolystoma xenopodis, is the frog’s most frequently co-introduced metazoan parasite. In an integrative approach, we utilised morphometrics and molecular markers to assess variation in P. xenopodis in its native range. We measured twelve key morphological characters from 23 flatworms and compared these statistically between flatworms collected from the northern- and southernmost distribution in South Africa. Phylogenetic analyses were based on three concatenated markers, namely 28S and 12S rDNA and COX1, from six flatworms. The combination of five morphological characters, which involve egg size, gut morphology and size of the attachment hooks, differentiated northern and southern populations of P. xenopodis. The multilocus phylogenetic analyses showed a cluster of northern P. xenopodis and two southern lineages with more basal positioning. These findings demonstrate a relatively high level of intraspecific variation in P. xenopodis in its native range. The presented intraspecific variation of P. xenopodis could be potentially informative to trace geographic origin in its non-native range.
非洲爪蛙（Xenopus laevis）是一种全球入侵者，在非洲南部的原生种群中表现出明显的系统地理分化，这似乎增强了它的入侵潜力。蛙类最常见的共同引进寄生虫是扁形多囊虫（Protopolystoma xenopodis）。我们采用了一种综合方法，利用形态计量学和分子标记来评估 P. xenopodis 在其原生地的变异。我们测量了 23 种扁形虫的 12 个关键形态特征，并对从南非最北和最南分布区采集的扁形虫进行了统计比较。系统发育分析是基于来自六种扁形虫的 28S 和 12S rDNA 以及 COX1 这三个联合标记进行的。五种形态特征（包括卵的大小、肠道形态和附钩的大小）的组合区分了 P. xenopodis 的北部和南部种群。多焦点系统进化分析表明，P. xenopodis 在北方有一个聚类，在南方有两个定位较低的品系。这些研究结果表明，P. xenopodis 在其原产地的种内变异水平相对较高。所呈现的 P. xenopodis 种内变异可能有助于追踪其非原生地的地理起源。
{"title":"Intraspecific morphological and genetic variation in South African populations of a polystomatid flatworm parasite","authors":"A. L. Schoeman, N. Kmentová, M. Vanhove, L. D. du Preez","doi":"10.26496/bjz.2024.118","DOIUrl":"https://doi.org/10.26496/bjz.2024.118","url":null,"abstract":"The African Clawed Frog Xenopus laevis, a global invader, exhibits a marked phylogeographic divergence among native populations in southern Africa, which seems to enhance its invasive potential. The polystomatid flatworm, Protopolystoma xenopodis, is the frog’s most frequently co-introduced metazoan parasite. In an integrative approach, we utilised morphometrics and molecular markers to assess variation in P. xenopodis in its native range. We measured twelve key morphological characters from 23 flatworms and compared these statistically between flatworms collected from the northern- and southernmost distribution in South Africa. Phylogenetic analyses were based on three concatenated markers, namely 28S and 12S rDNA and COX1, from six flatworms. The combination of five morphological characters, which involve egg size, gut morphology and size of the attachment hooks, differentiated northern and southern populations of P. xenopodis. The multilocus phylogenetic analyses showed a cluster of northern P. xenopodis and two southern lineages with more basal positioning. These findings demonstrate a relatively high level of intraspecific variation in P. xenopodis in its native range. The presented intraspecific variation of P. xenopodis could be potentially informative to trace geographic origin in its non-native range.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139774093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Borczyk, Przemysław Puszkiewicz, Stanisław Bury
Sexual dimorphism in the size and shape of the body and head is the result of manifold selective pressures acting on organisms. In snakes, sexual size dimorphism is common and has been well-studied. However, intersexual differences in relative head size and shape have attracted far less attention. Similarly, the allometric properties of head shape and size in snakes are poorly known. Here, we analyse sexual dimorphism in two viperid species: European adder Vipera berus (Linnaeus, 1758) and Steppe viper Vipera renardi (Christoph, 1861). We measured body length, tail length and several head characteristics: head length, head width, head height, pileus length, interorbital distance and internarial distance. Our findings were that males and females of both species did not differ in body length (SVL), but that males tended to have significantly longer tails; there were also significant differences in head characteristics – males tended to have higher heads, and larger internarial and interorbital distances. The head dimensions displayed negative allometry when compared against SVL but when scaled against head length, dimensions like head height and head width exhibited positive allometry. We argue that these differences may be related to sexual selection and that the wider heads may also serve as antipredatory signal.
{"title":"Sexual dimorphism and allometry in the head and body size of two viperid snakes (genus Vipera)","authors":"B. Borczyk, Przemysław Puszkiewicz, Stanisław Bury","doi":"10.26496/bjz.2024.117","DOIUrl":"https://doi.org/10.26496/bjz.2024.117","url":null,"abstract":"Sexual dimorphism in the size and shape of the body and head is the result of manifold selective pressures acting on organisms. In snakes, sexual size dimorphism is common and has been well-studied. However, intersexual differences in relative head size and shape have attracted far less attention. Similarly, the allometric properties of head shape and size in snakes are poorly known. Here, we analyse sexual dimorphism in two viperid species: European adder Vipera berus (Linnaeus, 1758) and Steppe viper Vipera renardi (Christoph, 1861). We measured body length, tail length and several head characteristics: head length, head width, head height, pileus length, interorbital distance and internarial distance. Our findings were that males and females of both species did not differ in body length (SVL), but that males tended to have significantly longer tails; there were also significant differences in head characteristics – males tended to have higher heads, and larger internarial and interorbital distances. The head dimensions displayed negative allometry when compared against SVL but when scaled against head length, dimensions like head height and head width exhibited positive allometry. We argue that these differences may be related to sexual selection and that the wider heads may also serve as antipredatory signal.","PeriodicalId":8750,"journal":{"name":"Belgian Journal of Zoology","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139852304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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