The evolution and maintenance of color clines is a classic topic of research in evolutionary ecology.However,studies analyzing the temporal dynamics of such clines are much less frequent,due to the difficulty of obtai...The evolution and maintenance of color clines is a classic topic of research in evolutionary ecology.However,studies analyzing the temporal dynamics of such clines are much less frequent,due to the difficulty of obtaining reliable data about past color distributions along environmen-tal gradients.In this article,we describe a case of decades-long temporal stability and directional change in a color cline of the marine snail Littorina saxatilis along the coastal inlet of the Ria de Vigo(NW Spain).L.saxatilis from this area shows a clear color cline with 3 distinct areas from the innermost to the more wave-exposed localities of the Ria:the inner,protected localities show an abundance of fawn-like individuals;the intermediate localities show a high diversity of colors;and the outer,wave-exposed localities show populations with a high frequency of a black and lineated morph.We compare data from the 1970s and 2022 in the same localities,showing that the cline has kept relatively stable for at least over half a century,except for some directional change and local variability in the frequency of certain morphs.Multiple regression analyses and biodiversity measures are presented to provide clues into the selective pressures that might be involved in the maintenance of this color cline.Future research avenues to properly test the explanatory power of these selective agents as well as the possible origins of the cline are discussed.展开更多
Based on the theory of oxidative stress, it is believed that the induction of antioxidant components of the cellular defense system reflects the adaptive compensatory response of an organism aimed at overcoming stress...Based on the theory of oxidative stress, it is believed that the induction of antioxidant components of the cellular defense system reflects the adaptive compensatory response of an organism aimed at overcoming stressful conditions. Therefore, this work concentrated on investigating the effect of the low and high tides on the antioxidant system of L. （Littorina） kurila and also compared the antioxidant parameters of two species of gastropods： intertidal--L, kurila and subtidal--L, squalida. The following parameters were evaluated in the hepatopancreas of mollusks： the activity of the antioxidant enzymes SOD （superoxide dismutase）, CAT （catalase）, and GR （glutathione reductase）, the production of ROS （reactive oxygen species）, and the levels of GSH （glutathione） and the lipid peroxidation product-MDA （malondialdehyde）. The results of this work indicate that the state of the antioxidant system of L. kurila reflected the adaptive capacity of the species in the changing environmental conditions.展开更多
Objective:To study the digenean parasites of the prosobranch gastropods,Littorina littorea(L.littorea)and Gibbula umbilicalis(G.umbilicalis)from rocky shores of the Northern Atlantic coast of Portugal.Methods:A total ...Objective:To study the digenean parasites of the prosobranch gastropods,Littorina littorea(L.littorea)and Gibbula umbilicalis(G.umbilicalis)from rocky shores of the Northern Atlantic coast of Portugal.Methods:A total of 413 L.littorea and 2603 G.umbilicalis were collected from rocky shores,at Aveiro estuary,Aguda Beach,and Foz Beach at Porto(Northern Atlantic coast of Portugal)from January to July 2014 and February 2014 to January 2015,respectively.Gonads and digestive glands of the gastropods were examined under light microscopy for the presence of digeneans.Infected gonads of L.littorea were prepared for histological observation,whereas digeneans found in G.umbilicalis were studied and identified with the aid of light and scanning electron microscopy.Results:Two species of digeneans were found infecting the digestive gland and gonads of G.umbilicalis,namely,Cainocreadium labracis and Lecithochirium furcolabiatum with a combined prevalence of 3%.Histological observations of gonads of L.littorea revealed the infection with digeneans,with considerable replacement of gonadal tissues.These digeneans were not identified to species level.The prevalence of digeneans in this snail host was 0.7%.Conclusions:The present study adds G.umbilicalis as another first intermediate host for Cainocreadium labracis and extends its geographical range to the Portuguese Atlantic coast.Cercariae of Lecithochirium furcolabiatum were previously reported from G.umbilicalis.A literature review of digeneans occurring in the gastropod genera Gibbula and Littorina is given.展开更多
基金support from the Ministerio de Ciencia e Innovacion(PID2021-124930NB-I00)Xunta de Galicia(GRC,ED431C 2020-05)+2 种基金Centro singular de Investigacion de Galicia accreditation 2019-2022,and the European Union(European Regional Development Fund-ERDF)Juan Galindo was funded by a JIN project(Jovenes Investigadores,Ministerio de Ciencia,Innovacion y Universidades,RTI2018-101274-J-100)Juan Gefaell was funded by a Xunta de Galicia Predoctoral Research Contract(ED481A-2021/274).
文摘The evolution and maintenance of color clines is a classic topic of research in evolutionary ecology.However,studies analyzing the temporal dynamics of such clines are much less frequent,due to the difficulty of obtaining reliable data about past color distributions along environmen-tal gradients.In this article,we describe a case of decades-long temporal stability and directional change in a color cline of the marine snail Littorina saxatilis along the coastal inlet of the Ria de Vigo(NW Spain).L.saxatilis from this area shows a clear color cline with 3 distinct areas from the innermost to the more wave-exposed localities of the Ria:the inner,protected localities show an abundance of fawn-like individuals;the intermediate localities show a high diversity of colors;and the outer,wave-exposed localities show populations with a high frequency of a black and lineated morph.We compare data from the 1970s and 2022 in the same localities,showing that the cline has kept relatively stable for at least over half a century,except for some directional change and local variability in the frequency of certain morphs.Multiple regression analyses and biodiversity measures are presented to provide clues into the selective pressures that might be involved in the maintenance of this color cline.Future research avenues to properly test the explanatory power of these selective agents as well as the possible origins of the cline are discussed.
文摘Based on the theory of oxidative stress, it is believed that the induction of antioxidant components of the cellular defense system reflects the adaptive compensatory response of an organism aimed at overcoming stressful conditions. Therefore, this work concentrated on investigating the effect of the low and high tides on the antioxidant system of L. （Littorina） kurila and also compared the antioxidant parameters of two species of gastropods： intertidal--L, kurila and subtidal--L, squalida. The following parameters were evaluated in the hepatopancreas of mollusks： the activity of the antioxidant enzymes SOD （superoxide dismutase）, CAT （catalase）, and GR （glutathione reductase）, the production of ROS （reactive oxygen species）, and the levels of GSH （glutathione） and the lipid peroxidation product-MDA （malondialdehyde）. The results of this work indicate that the state of the antioxidant system of L. kurila reflected the adaptive capacity of the species in the changing environmental conditions.
基金supported by the“Direcção Regional de Agricultura e Pescas do Centro,Divisão de Investimentos de Aveiro”,Portugal,under project“Probur”(Grant No.31-03-05-FEP-0039).
文摘Objective:To study the digenean parasites of the prosobranch gastropods,Littorina littorea(L.littorea)and Gibbula umbilicalis(G.umbilicalis)from rocky shores of the Northern Atlantic coast of Portugal.Methods:A total of 413 L.littorea and 2603 G.umbilicalis were collected from rocky shores,at Aveiro estuary,Aguda Beach,and Foz Beach at Porto(Northern Atlantic coast of Portugal)from January to July 2014 and February 2014 to January 2015,respectively.Gonads and digestive glands of the gastropods were examined under light microscopy for the presence of digeneans.Infected gonads of L.littorea were prepared for histological observation,whereas digeneans found in G.umbilicalis were studied and identified with the aid of light and scanning electron microscopy.Results:Two species of digeneans were found infecting the digestive gland and gonads of G.umbilicalis,namely,Cainocreadium labracis and Lecithochirium furcolabiatum with a combined prevalence of 3%.Histological observations of gonads of L.littorea revealed the infection with digeneans,with considerable replacement of gonadal tissues.These digeneans were not identified to species level.The prevalence of digeneans in this snail host was 0.7%.Conclusions:The present study adds G.umbilicalis as another first intermediate host for Cainocreadium labracis and extends its geographical range to the Portuguese Atlantic coast.Cercariae of Lecithochirium furcolabiatum were previously reported from G.umbilicalis.A literature review of digeneans occurring in the gastropod genera Gibbula and Littorina is given.
