Rethinking resting eggs decapsulating
Abstract Aim Temperature and light have been recognized as important factors for ephippia hatching in temperate and tropical freshwater systems. Oddly some authors suggested that decapsulation of resting eggs would be a pro when it comes to ex situ hatching studies, exposing those eggs to a greater...
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| Format: | Article |
| Language: | English |
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Associação Brasileira de Limnologia
2019-10-01
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| Series: | Acta Limnologica Brasiliensia |
| Subjects: | |
| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2179-975X2019000100324&tlng=en |
| _version_ | 1819243503948922880 |
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| author | Marina Isabela Bessa da Silva Déborah Maria de Oliveira Luciana Pena Mello Brandão Francisco Antônio Rodrigues Barbosa Paulina Maria Maia-Barbosa |
| author_facet | Marina Isabela Bessa da Silva Déborah Maria de Oliveira Luciana Pena Mello Brandão Francisco Antônio Rodrigues Barbosa Paulina Maria Maia-Barbosa |
| author_sort | Marina Isabela Bessa da Silva |
| collection | DOAJ |
| description | Abstract Aim Temperature and light have been recognized as important factors for ephippia hatching in temperate and tropical freshwater systems. Oddly some authors suggested that decapsulation of resting eggs would be a pro when it comes to ex situ hatching studies, exposing those eggs to a greater amount of light. This study aimed to compare the difference in the hatching rate between resting eggs decapsulated and intact ephippia of Daphnia laevis, a zooplankton that occurs at lakes, in tropical freshwaters (Cladocera). Methods The ephippia used in this work were collected at the sediment of a reservoir, in Belo Horizonte city (Minas Gerais, Brazil). We set up the laboratory experiment with two distinct groups: intact ephippia and decapsulated resting eggs. For that, we manually decapsulated 120 ephippia and kept 120 others intact (six replicas with 20 ephippia each), then incubated them all with culture water at 22ºC (12h photoperiod) for 30 days with daily monitoring. Results The results showed that decapsulation influenced negatively the hatching success, as the intact ephippia had a hatching rate of 22%, while those decapsulated only had 6%. In addition, Daphnia hatchlings were observed for intact ephippia group up to the twenty-seventh day, while for the decapsulated the last hatching occurred on the tenth day. Decapsulated eggs are subject to high exposure to light and it may jeopardize the embryo development. Conclusions In this context, we suggest that removing the protective capsule from the eggs needs to be done with caution, since in some species this can damage the resting eggs, which alters the viability and compromise the accuracy of the hatching rates studies. |
| first_indexed | 2024-12-23T14:56:44Z |
| format | Article |
| id | doaj.art-6d30518a64844421836f93ead47c6efc |
| institution | Directory Open Access Journal |
| issn | 2179-975X |
| language | English |
| last_indexed | 2024-12-23T14:56:44Z |
| publishDate | 2019-10-01 |
| publisher | Associação Brasileira de Limnologia |
| record_format | Article |
| series | Acta Limnologica Brasiliensia |
| spelling | doaj.art-6d30518a64844421836f93ead47c6efc2022-12-21T17:42:44ZengAssociação Brasileira de LimnologiaActa Limnologica Brasiliensia2179-975X2019-10-013110.1590/s2179-975x2418Rethinking resting eggs decapsulatingMarina Isabela Bessa da Silvahttps://orcid.org/0000-0001-8471-6994Déborah Maria de Oliveirahttps://orcid.org/0000-0002-6699-6379Luciana Pena Mello Brandãohttps://orcid.org/0000-0001-7219-1035Francisco Antônio Rodrigues Barbosahttps://orcid.org/0000-0001-6488-1538Paulina Maria Maia-Barbosahttps://orcid.org/0000-0002-5121-5648Abstract Aim Temperature and light have been recognized as important factors for ephippia hatching in temperate and tropical freshwater systems. Oddly some authors suggested that decapsulation of resting eggs would be a pro when it comes to ex situ hatching studies, exposing those eggs to a greater amount of light. This study aimed to compare the difference in the hatching rate between resting eggs decapsulated and intact ephippia of Daphnia laevis, a zooplankton that occurs at lakes, in tropical freshwaters (Cladocera). Methods The ephippia used in this work were collected at the sediment of a reservoir, in Belo Horizonte city (Minas Gerais, Brazil). We set up the laboratory experiment with two distinct groups: intact ephippia and decapsulated resting eggs. For that, we manually decapsulated 120 ephippia and kept 120 others intact (six replicas with 20 ephippia each), then incubated them all with culture water at 22ºC (12h photoperiod) for 30 days with daily monitoring. Results The results showed that decapsulation influenced negatively the hatching success, as the intact ephippia had a hatching rate of 22%, while those decapsulated only had 6%. In addition, Daphnia hatchlings were observed for intact ephippia group up to the twenty-seventh day, while for the decapsulated the last hatching occurred on the tenth day. Decapsulated eggs are subject to high exposure to light and it may jeopardize the embryo development. Conclusions In this context, we suggest that removing the protective capsule from the eggs needs to be done with caution, since in some species this can damage the resting eggs, which alters the viability and compromise the accuracy of the hatching rates studies.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2179-975X2019000100324&tlng=enDaphnia laevisephippiadiapausehatching rateszooplankton |
| spellingShingle | Marina Isabela Bessa da Silva Déborah Maria de Oliveira Luciana Pena Mello Brandão Francisco Antônio Rodrigues Barbosa Paulina Maria Maia-Barbosa Rethinking resting eggs decapsulating Acta Limnologica Brasiliensia Daphnia laevis ephippia diapause hatching rates zooplankton |
| title | Rethinking resting eggs decapsulating |
| title_full | Rethinking resting eggs decapsulating |
| title_fullStr | Rethinking resting eggs decapsulating |
| title_full_unstemmed | Rethinking resting eggs decapsulating |
| title_short | Rethinking resting eggs decapsulating |
| title_sort | rethinking resting eggs decapsulating |
| topic | Daphnia laevis ephippia diapause hatching rates zooplankton |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2179-975X2019000100324&tlng=en |
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