Pub Date : 2020-09-16DOI: 10.1080/07924259.2020.1821798
E. Vortsepneva, Y. Khramova, D. A. Nikishin
ABSTRACT Development of the limpet Testudinalia testudinalis collected from the White Sea was studied using light and scanning electron microscopy. Cleavage and early development of T. testudinalis were consistent with the general pattern of patellogastropod development, differing in only minor details, such as temperature-dependent developmental rates. A pre-torsional veliger radula was detected by calcofluor white staining of unpolymerized chitin. The veliger radula consisted of nine transverse rows with three teeth per row, which transformed into the radula of newly settled juveniles with five teeth per row (one central and two pairs of lateral teeth). The juvenile radula, with two pairs of lateral and one pair of hook-like marginal teeth, resembled the adult radula in terms of teeth form and co-localization. Radula formation differs between the larva and adult in that each tooth is formed by several odontoblasts and microvillar secretion in the former, whereas it is formed by numerous cells and apocrine secretion in the latter.
{"title":"Development of the limpet Testudinalia testudinalis (O.F. Müller, 1776) (Patellogastropoda, Mollusca) from the White Sea, with special reference to the radula","authors":"E. Vortsepneva, Y. Khramova, D. A. Nikishin","doi":"10.1080/07924259.2020.1821798","DOIUrl":"https://doi.org/10.1080/07924259.2020.1821798","url":null,"abstract":"ABSTRACT Development of the limpet Testudinalia testudinalis collected from the White Sea was studied using light and scanning electron microscopy. Cleavage and early development of T. testudinalis were consistent with the general pattern of patellogastropod development, differing in only minor details, such as temperature-dependent developmental rates. A pre-torsional veliger radula was detected by calcofluor white staining of unpolymerized chitin. The veliger radula consisted of nine transverse rows with three teeth per row, which transformed into the radula of newly settled juveniles with five teeth per row (one central and two pairs of lateral teeth). The juvenile radula, with two pairs of lateral and one pair of hook-like marginal teeth, resembled the adult radula in terms of teeth form and co-localization. Radula formation differs between the larva and adult in that each tooth is formed by several odontoblasts and microvillar secretion in the former, whereas it is formed by numerous cells and apocrine secretion in the latter.","PeriodicalId":14482,"journal":{"name":"Invertebrate Reproduction & Development","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07924259.2020.1821798","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42608781","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}
Pub Date : 2020-09-14DOI: 10.1080/07924259.2020.1821799
A. R. da Silva, Luiz Gustavo Mendes Lemes, C. S. Nogueira, P. Bispo, A. Castilho
ABSTRACT Aegla quilombola is an anomuran crab endemic to São Paulo State, Brazil. The present manuscript aims to provide information about sexual dimorphism using geometric morphometrics, as well as information about heterochely, laterality and sexual maturity. The specimens were sampled in Intervales State Park. The carapace and chelipeds of all animals were photographed and landmarks digitalized. In the analyses, the propodus of the first pair of pereopods (chelipeds) were used. The same structures were measured for morphometric sexual maturity, analysing the relationships between carapace length (CL) x propodus height for males, and CL x abdomen length (ABL) for females. For heterochely and laterality, the height of male and female chelipeds were evaluated. Morphological differences were found in the shape of the posterior margin of the carapace and in the chelipeds’ palmar region. Males reached morphometric maturity at smaller sizes and showed heterochely and laterality, usually having a larger left cheliped. These differences are probably related to differential energy use by males and females in fulfiling specific ecological roles. Females had larger abdominal margins to invest in reproduction and males invested energy in chelipeds that were more robust and larger than females, as chelipeds are often used in agonistic interactions and to obtain better resources.
{"title":"Heteroquely, laterality, maturity body size and shape variation of males and females of the endemic South American anomuran Aegla quilombola Moraes, Tavares & Bueno, 2017","authors":"A. R. da Silva, Luiz Gustavo Mendes Lemes, C. S. Nogueira, P. Bispo, A. Castilho","doi":"10.1080/07924259.2020.1821799","DOIUrl":"https://doi.org/10.1080/07924259.2020.1821799","url":null,"abstract":"ABSTRACT Aegla quilombola is an anomuran crab endemic to São Paulo State, Brazil. The present manuscript aims to provide information about sexual dimorphism using geometric morphometrics, as well as information about heterochely, laterality and sexual maturity. The specimens were sampled in Intervales State Park. The carapace and chelipeds of all animals were photographed and landmarks digitalized. In the analyses, the propodus of the first pair of pereopods (chelipeds) were used. The same structures were measured for morphometric sexual maturity, analysing the relationships between carapace length (CL) x propodus height for males, and CL x abdomen length (ABL) for females. For heterochely and laterality, the height of male and female chelipeds were evaluated. Morphological differences were found in the shape of the posterior margin of the carapace and in the chelipeds’ palmar region. Males reached morphometric maturity at smaller sizes and showed heterochely and laterality, usually having a larger left cheliped. These differences are probably related to differential energy use by males and females in fulfiling specific ecological roles. Females had larger abdominal margins to invest in reproduction and males invested energy in chelipeds that were more robust and larger than females, as chelipeds are often used in agonistic interactions and to obtain better resources.","PeriodicalId":14482,"journal":{"name":"Invertebrate Reproduction & Development","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07924259.2020.1821799","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47102977","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}
Pub Date : 2020-08-31DOI: 10.1080/07924259.2020.1815875
Nami Okubo, Y. Nakano, M. Mita
ABSTRACT Most reef-building corals are hermaphroditic and discharge buoyant bundles that contain a mixture of eggs and spermatozoa during the breeding season. The buoyancy of the bundles is due to wax-esters. This study analysed and compared the lipid compositions in eight species of corals. Overall, 60–80% of the total lipid composition of the eggs or embryos of six species, Acropora digitifera, A. florida, A. monticulosa, Dipsastraea lizardensis, Ctenactis echinata, and Pseudosiderastrea tayamai that discharged buoyant eggs was wax-esters. Although Galaxea fascicularis is a dioecious coral, the bundle released from males (or hermaphrodites) contained spermatozoa and pseudo-eggs. Both eggs and pseudo-eggs contained high amounts of wax-esters. In contrast, the wax-ester content in sedimenting eggs released from Oulastrea crispata was very low. Thus, this study confirmed the presence of wax-esters in buoyant egg bundles. This suggests that wax-esters play a role in the dispersal and settlement potential of planula larvae in corals.
{"title":"Lipid composition of gametes in scleractinian reef-building corals: wax-esters generate buoyancy for the gametes","authors":"Nami Okubo, Y. Nakano, M. Mita","doi":"10.1080/07924259.2020.1815875","DOIUrl":"https://doi.org/10.1080/07924259.2020.1815875","url":null,"abstract":"ABSTRACT Most reef-building corals are hermaphroditic and discharge buoyant bundles that contain a mixture of eggs and spermatozoa during the breeding season. The buoyancy of the bundles is due to wax-esters. This study analysed and compared the lipid compositions in eight species of corals. Overall, 60–80% of the total lipid composition of the eggs or embryos of six species, Acropora digitifera, A. florida, A. monticulosa, Dipsastraea lizardensis, Ctenactis echinata, and Pseudosiderastrea tayamai that discharged buoyant eggs was wax-esters. Although Galaxea fascicularis is a dioecious coral, the bundle released from males (or hermaphrodites) contained spermatozoa and pseudo-eggs. Both eggs and pseudo-eggs contained high amounts of wax-esters. In contrast, the wax-ester content in sedimenting eggs released from Oulastrea crispata was very low. Thus, this study confirmed the presence of wax-esters in buoyant egg bundles. This suggests that wax-esters play a role in the dispersal and settlement potential of planula larvae in corals.","PeriodicalId":14482,"journal":{"name":"Invertebrate Reproduction & Development","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07924259.2020.1815875","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47001587","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}
Pub Date : 2020-08-20DOI: 10.1080/07924259.2020.1806119
M. Seiter, Laurin Mosetig, N. Milasowszky
ABSTRACT Scorpions often experience food shortages, yet information on their baseline nutritional input is lacking. In many life histories, there is a trade-off between adult size and development time that is interrelated with food availability. We present precise data on the influence of two different feeding regimes that affect development in the buthid scorpion Tityus neibae. The results indicate a strong relationship between the treatment group, sex, morphometrics and life stages. The different diet inputs had no influence on the embryonic development or the litter size but had a major effect on the postembryonic development time and on the life stage when individuals reached maturity. No females or males reached maturity by the 4th instar when fed every two weeks and only males that were fed weekly were able to reach maturity by the 4th. Thus, a trade-off in T. neibae males is apparent, since they can reach maturity earlier in life, resulting in an overall smaller body size that may reduce the risk of predation. By contrast, females may have been selected to reach full development with an overall larger body size that results in an increase in the fitness, the number, or the size of the offspring.
{"title":"The trade-off between adult size and development time due to different feeding regimes in the scorpion Tityus neibae","authors":"M. Seiter, Laurin Mosetig, N. Milasowszky","doi":"10.1080/07924259.2020.1806119","DOIUrl":"https://doi.org/10.1080/07924259.2020.1806119","url":null,"abstract":"ABSTRACT Scorpions often experience food shortages, yet information on their baseline nutritional input is lacking. In many life histories, there is a trade-off between adult size and development time that is interrelated with food availability. We present precise data on the influence of two different feeding regimes that affect development in the buthid scorpion Tityus neibae. The results indicate a strong relationship between the treatment group, sex, morphometrics and life stages. The different diet inputs had no influence on the embryonic development or the litter size but had a major effect on the postembryonic development time and on the life stage when individuals reached maturity. No females or males reached maturity by the 4th instar when fed every two weeks and only males that were fed weekly were able to reach maturity by the 4th. Thus, a trade-off in T. neibae males is apparent, since they can reach maturity earlier in life, resulting in an overall smaller body size that may reduce the risk of predation. By contrast, females may have been selected to reach full development with an overall larger body size that results in an increase in the fitness, the number, or the size of the offspring.","PeriodicalId":14482,"journal":{"name":"Invertebrate Reproduction & Development","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07924259.2020.1806119","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45172373","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}
Pub Date : 2020-08-13DOI: 10.1080/07924259.2020.1808095
A. Ayanath, Sudha Devi Arath Raghavan
ABSTRACT The sesquiterpenoid, methyl farnesoate, produced by the mandibular organ of decapod crustaceans has a variety of functions including the regulation of moulting, reproduction, morphogenesis, behaviour and osmoregulation. This study used gas chromatography and mass spectrometric analysis to measure the haemolymph concentration of methyl farnesoate during various developmental stages of the ovary of the edible freshwater crab Travancoriana schirnerae. The results revealed exceptionally low methyl farnesoate titres in the haemolymph during the avitellogenic and previtellogenic periods (5.7 ± 0.7 and 12.8 ± 1.3 ng/mL, respectively), reaching a peak in the early vitellogenic period (91.8 ± 3.8 ng/mL), followed by a significant fall during the middle and late vitellogenic stages (32.1 ± 2.3 and 22.1 ± 1.6 ng/mL, respectively). The progressive increase and decrease in the haemolymph titre of methyl farnesoate in accordance with the stages of the ovarian cycle clearly indicated the role of this hormone in growth and maturation of the ovary. Furthermore, administration of methyl farnesoate can be exploited as an alternate method to the traditional eyestalk ablation practised for inducing ovarian maturation and spawning.
{"title":"Profiling of methyl farnesoate in relation to female reproductive cycle in the freshwater crab, Travancoriana schirnerae Bott, 1969 (Crustacea: Gecarcinucidae)","authors":"A. Ayanath, Sudha Devi Arath Raghavan","doi":"10.1080/07924259.2020.1808095","DOIUrl":"https://doi.org/10.1080/07924259.2020.1808095","url":null,"abstract":"ABSTRACT The sesquiterpenoid, methyl farnesoate, produced by the mandibular organ of decapod crustaceans has a variety of functions including the regulation of moulting, reproduction, morphogenesis, behaviour and osmoregulation. This study used gas chromatography and mass spectrometric analysis to measure the haemolymph concentration of methyl farnesoate during various developmental stages of the ovary of the edible freshwater crab Travancoriana schirnerae. The results revealed exceptionally low methyl farnesoate titres in the haemolymph during the avitellogenic and previtellogenic periods (5.7 ± 0.7 and 12.8 ± 1.3 ng/mL, respectively), reaching a peak in the early vitellogenic period (91.8 ± 3.8 ng/mL), followed by a significant fall during the middle and late vitellogenic stages (32.1 ± 2.3 and 22.1 ± 1.6 ng/mL, respectively). The progressive increase and decrease in the haemolymph titre of methyl farnesoate in accordance with the stages of the ovarian cycle clearly indicated the role of this hormone in growth and maturation of the ovary. Furthermore, administration of methyl farnesoate can be exploited as an alternate method to the traditional eyestalk ablation practised for inducing ovarian maturation and spawning.","PeriodicalId":14482,"journal":{"name":"Invertebrate Reproduction & Development","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07924259.2020.1808095","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48109933","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}
Pub Date : 2020-06-25DOI: 10.1080/07924259.2020.1784298
K. Anderson, Mateus Pepinelli, S. Kvist
ABSTRACT In the embryonic blast cells of leeches, segmental identity is conferred in a cell-intrinsic manner (i.e., with temporal rather than spatial signals), at or shortly after the birth of the cell. If these blast cells are destroyed in only one of the two germinal bandlets that form the ventral midline, this can result in segment-specific features that fall out of register on either side of the leech body. Here we present a specimen of the leech Erpobdella punctata, in which the gonopores have been duplicated and the male and female reproductive tracts are out of register between the left and right sides of the body. To confirm the identity of the specimen, we use a phylogenetic approach and high-resolution stereo microscopy. The probable cause of the phenotypic anomaly is discussed.
{"title":"Natural occurrence of an experimental developmental phenotype in the leech Erpobdella punctata (Leidy 1870) (Annelida: Clitellata: Hirudinea)","authors":"K. Anderson, Mateus Pepinelli, S. Kvist","doi":"10.1080/07924259.2020.1784298","DOIUrl":"https://doi.org/10.1080/07924259.2020.1784298","url":null,"abstract":"ABSTRACT In the embryonic blast cells of leeches, segmental identity is conferred in a cell-intrinsic manner (i.e., with temporal rather than spatial signals), at or shortly after the birth of the cell. If these blast cells are destroyed in only one of the two germinal bandlets that form the ventral midline, this can result in segment-specific features that fall out of register on either side of the leech body. Here we present a specimen of the leech Erpobdella punctata, in which the gonopores have been duplicated and the male and female reproductive tracts are out of register between the left and right sides of the body. To confirm the identity of the specimen, we use a phylogenetic approach and high-resolution stereo microscopy. The probable cause of the phenotypic anomaly is discussed.","PeriodicalId":14482,"journal":{"name":"Invertebrate Reproduction & Development","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07924259.2020.1784298","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48198740","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}
Pub Date : 2020-05-21DOI: 10.1080/07924259.2020.1769747
S. Mukherjee, P. Basu, G. Saha, G. Aditya
ABSTRACT The effect of larval feeding on the life history traits of the mottled emigrant butterfly Catopsilia pyranthe (Linnaeus, 1758) (Lepidoptera: Pieridae) was assessed to link life history variations as a function of food availability. The 0-day-old larvae of C. pyranthe were reared with varying quantity of food (100, 200, 400, 800, 1600 and 3200 mg/day) against a control set with ad libitum food availability. Significant differences in instar duration and body weight of the larva and therefore fitness were found in relation to the amount of food available. In urban regions like Kolkata, India, disparity in food availability may induce variations in life history traits and thus fitness and survival in C. pyranthe.
{"title":"Food dependent changes of the life history traits of Catopsilia pyranthe (Lepidoptera: Pieridae)","authors":"S. Mukherjee, P. Basu, G. Saha, G. Aditya","doi":"10.1080/07924259.2020.1769747","DOIUrl":"https://doi.org/10.1080/07924259.2020.1769747","url":null,"abstract":"ABSTRACT The effect of larval feeding on the life history traits of the mottled emigrant butterfly Catopsilia pyranthe (Linnaeus, 1758) (Lepidoptera: Pieridae) was assessed to link life history variations as a function of food availability. The 0-day-old larvae of C. pyranthe were reared with varying quantity of food (100, 200, 400, 800, 1600 and 3200 mg/day) against a control set with ad libitum food availability. Significant differences in instar duration and body weight of the larva and therefore fitness were found in relation to the amount of food available. In urban regions like Kolkata, India, disparity in food availability may induce variations in life history traits and thus fitness and survival in C. pyranthe.","PeriodicalId":14482,"journal":{"name":"Invertebrate Reproduction & Development","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07924259.2020.1769747","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46734903","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}
Pub Date : 2020-05-13DOI: 10.1080/07924259.2020.1762771
Mehmet Cìlbìz
ABSTRACT The pleopodal fecundity of Pontastacus leptodactylus from Hirfanlı Dam (Turkey) was investigated. Reproductive period, length at first maturity, as well as the number, weight and diameter of pleopodal eggs were determined. The study was conducted monthly at six different stations from June 2017 to May 2018. Berried females were observed between December and May. L50 length at first maturity of the female crayfish population in the lake was estimated as 9.04 cm and this value is below the applied 10 cm Minimum Landing Size (MLS). The mean egg number of the population was 240.18, the mean egg weight was 0.0122 g and the mean egg diameter was 2.702 mm. While an increase in female total length had a positive effect on mean total egg number, sampling period (progressive incubation period from December to May) caused negative effects. The mean total egg number for 1 mm total length was found to be 2.18. When the mean pleopodal egg number of the crayfish population in Hirfanlı Dam Lake was compared with populations of P. leptodactylus in other localities it was concluded that the stock is quite productive.
{"title":"Pleopodal fecundity of narrow-clawed crayfish (Pontastacus leptodactylus Eschscholtz, 1823)","authors":"Mehmet Cìlbìz","doi":"10.1080/07924259.2020.1762771","DOIUrl":"https://doi.org/10.1080/07924259.2020.1762771","url":null,"abstract":"ABSTRACT The pleopodal fecundity of Pontastacus leptodactylus from Hirfanlı Dam (Turkey) was investigated. Reproductive period, length at first maturity, as well as the number, weight and diameter of pleopodal eggs were determined. The study was conducted monthly at six different stations from June 2017 to May 2018. Berried females were observed between December and May. L50 length at first maturity of the female crayfish population in the lake was estimated as 9.04 cm and this value is below the applied 10 cm Minimum Landing Size (MLS). The mean egg number of the population was 240.18, the mean egg weight was 0.0122 g and the mean egg diameter was 2.702 mm. While an increase in female total length had a positive effect on mean total egg number, sampling period (progressive incubation period from December to May) caused negative effects. The mean total egg number for 1 mm total length was found to be 2.18. When the mean pleopodal egg number of the crayfish population in Hirfanlı Dam Lake was compared with populations of P. leptodactylus in other localities it was concluded that the stock is quite productive.","PeriodicalId":14482,"journal":{"name":"Invertebrate Reproduction & Development","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07924259.2020.1762771","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41848032","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}
Pub Date : 2020-05-13DOI: 10.1080/07924259.2020.1764117
M. S. Khan, C. Whittington, M. Thompson, M. Byrne
ABSTRACT The temporal pattern of juvenile release by two species of viviparous asterinid sea stars that incubate their young in the gonads was documented. Parvulastra parvivipara released juveniles (400–3000 µm diameter) in 1–5 cohorts. Parents produced large juveniles (>1000-µm) irrespective of adult size. Released juveniles were larger than the retained juveniles. Most Cryptasterina hystera offspring were released in one large clutch of similarly sized juveniles (732-µm mean diameter). After this initial release, the presence of large juveniles (944-µm mean diameter) in the gonads of C. hystera indicates that they are supported by matrotrophy, potentially through sibling cannibalism. The degree of parental investment additional to the egg in both species was estimated by using a matrotrophy index (MI, the ratio of juvenile and egg dry mass). As the eggs of P. parvivipara and C. hystera could not be isolated, the eggs of their congeners (P. exigua and C. pentagona, respectively) were used as a proxy to estimate the MI, the first application of this index to a marine invertebrate. The MI ranged from 597 to 55082 in P. parvivipara and 1.7–6.2 in C. hystera for juveniles across the different size classes. Matrotrophy and size variation of offspring may be characteristics of echinoderms that incubate their young.
{"title":"Temporal pattern of offspring release and degree of parental investment in two viviparous asterinid sea stars with an overview of matrotrophy and offspring size variation in echinoderms that care for their offspring","authors":"M. S. Khan, C. Whittington, M. Thompson, M. Byrne","doi":"10.1080/07924259.2020.1764117","DOIUrl":"https://doi.org/10.1080/07924259.2020.1764117","url":null,"abstract":"ABSTRACT The temporal pattern of juvenile release by two species of viviparous asterinid sea stars that incubate their young in the gonads was documented. Parvulastra parvivipara released juveniles (400–3000 µm diameter) in 1–5 cohorts. Parents produced large juveniles (>1000-µm) irrespective of adult size. Released juveniles were larger than the retained juveniles. Most Cryptasterina hystera offspring were released in one large clutch of similarly sized juveniles (732-µm mean diameter). After this initial release, the presence of large juveniles (944-µm mean diameter) in the gonads of C. hystera indicates that they are supported by matrotrophy, potentially through sibling cannibalism. The degree of parental investment additional to the egg in both species was estimated by using a matrotrophy index (MI, the ratio of juvenile and egg dry mass). As the eggs of P. parvivipara and C. hystera could not be isolated, the eggs of their congeners (P. exigua and C. pentagona, respectively) were used as a proxy to estimate the MI, the first application of this index to a marine invertebrate. The MI ranged from 597 to 55082 in P. parvivipara and 1.7–6.2 in C. hystera for juveniles across the different size classes. Matrotrophy and size variation of offspring may be characteristics of echinoderms that incubate their young.","PeriodicalId":14482,"journal":{"name":"Invertebrate Reproduction & Development","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07924259.2020.1764117","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45639156","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}
Pub Date : 2020-05-13DOI: 10.1080/07924259.2020.1762772
L. Wyns, A. Semeraro, T. Sterckx, D. Delbare, G. Van Hoey
ABSTRACT Current coastal protection measures become increasingly insufficient under circumstances of climate change and increasing anthropogenic pressures. Aggregations of the ecosystem engineer Lanice conchilega (Pallas, 1766) stabilize the sediment bed of sandy shorelines. Therefore, this polychaete is considered an interesting target species in the search for nature-inspired designs in coastal zone management. This study investigated the potential of L. conchilega as a resilient coastal builder by trying to cultivate them and enhancing the larval settling process by using artificial substrata. A closed Recirculating aquaculture system (RAS) combining spawning induction and larval rearing was designed and tested. The tanks with adults were exposed to different photoperiods prior to water temperature rise. A spawning and fertilisation event was recorded in the 0:24 Light:Dark (LD) tank up to the trochophore stage. Additionally, the temperature-shock spawning induction method was experimentally proved effective. All practical experience on the in vitro spawning induction and larval rearing of L. conchilega is discussed and summarized as a guideline for future culturing trials. In vitro substratum settlement experiments with aulophore larvae sampled with plankton hauling revealed the potential of artificial substrata to trap larvae. Nonetheless, a preference in substratum type is not to be excluded yet.
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