<i>Heterocypris</i>(Crustacea: Ostracoda) from the Isole Pelagie (Sicily, Italy): Hatching phenology of resting eggs

Rossi, Valeria; Bartoli, Marco; Bellavere, Carlo; Gandolfi, A.; Salvador, Elisa; Menozzi, Paolo

doi:10.1080/11250000409356576

Cited by 22 publications

(16 citation statements)

References 48 publications

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“…were retrieved in comparable numbers from sediments collected after repeated inundations under laboratory conditions (25 males for 31 females and eight males for six females); these numbers include only the females with a lamina hyalina as only these were identified as sexual individuals. In another hatching experiment (Rossi et al. , 2004), using factorial combinations of temperatures and photoperiods, sex ratios of H. incongruens hatchlings either did not differ significantly from 1 : 1 (108 males for 124 sexual females) or were male biased (41 males for 20 sexual females).…”

Section: Discussionmentioning

confidence: 97%

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Experimental assessment of the fecundity of Eucypris virens (Ostracoda, Crustacea) under natural sex ratios

Vandekerkhove

Matzke‐Karasz²,

Mezquita

et al. 2007

Freshwater Biology

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1. The adaptive significance of the observed variations in sex ratios in non-marine ostracods is unclear. This study quantified the fecundity of females taken from a presumed fully sexual Eucypris virens population that were experimentally combined with different proportions of males (male : female sex ratios: 1 : 1, 1 : 2, 1 : 4, 1 : 8 and 0 : 1). 2. The results yielded no indications that female fecundity is altered by short-term variations in the proportion of males, at least not within the range of sex ratios that are common in natural ostracod populations. Complete removal of males, however, did strongly reduce hatching success of dried eggs. This suggests the need for multiple mating events during the reproductive lifetime of the female. It also emphasizes the need for a minimum number of males, although this minimum number evidently may be rather low, as we found a high number of spermatozoa in the seminal receptacles after a single mating event.3. The sex ratio in the source population was strongly female biased (1 : 3.4; n ¼ 514), whereas in the hatchling assemblages reared in the laboratory, males and females were found in equal proportions (1 : 1.0; n ¼ 1516), irrespective of the prevailing sex ratio. This clear discrepancy is intriguing, and points to the importance of epigenetic factors for the determination of field sex ratios.

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Section: Discussionmentioning

confidence: 97%

“…However, maternal effects are unlikely to explain the mismatch between offspring sex ratio (1 : 1.0; n = 1516) and field sex ratio (1 : 3.4; n = 514). In another study (Rossi et al. , 2004), male and female hatchlings of Heterocypris sp.…”

Section: Discussionmentioning

confidence: 98%

Experimental assessment of the fecundity of Eucypris virens (Ostracoda, Crustacea) under natural sex ratios

Vandekerkhove

Matzke‐Karasz²,

Mezquita

et al. 2007

Freshwater Biology

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“…In our experiments, we used apomictic females from a temporary pond, Cavallo Bianco, on Lampedusa Island, (35°25' N, 12°35' E) where only parthenogenetic females were found (Rossi et al., ). This population is made of at least eight clonal lineages (multilocus genotypes), and two main clonal lineages were dominant with frequencies between 20 and 66% (Rossi et al., ). Clonal lineages from Lampedusa are genetically different from those we described in Northern Italy (Rossi et al., , , ).…”

Section: Methodsmentioning

confidence: 99%

“…Seasonal succession or selection of specialized ecotypes allows the species' persistence in the temporary pools of the seasonal, predictable, continental climate (Rossi and Menozzi, ; Otero et al., , ). In Heterocypris , we described resting eggs that prolonged dormancy over more than one hydroperiod (Rossi et al., , , ). We showed that hatching asynchrony of resting eggs affects the performance of females and may be considered as a risk‐spreading strategy (Rossi et al., ).…”

Section: Introductionmentioning

confidence: 99%

Mother's Age and Hatching Phenology Strategy ofHeterocypris incongruens(Crustacea: Ostracoda) in Unpredictable Environment

2016

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We report experimental evidence of egg polyphenism in clonal lineages of Heterocypris incongruens from an ephemeral pond on a Mediterranean Island (Lampedusa, Italy). In controlled laboratory conditions, clonal females produced three different kinds of eggs: (i) resting and desiccation-resistant eggs, (ii) nonresting eggs that hatched gradually within 2 month hydroperiod, and (iii) nonresting delayed development eggs that hatched synchronously. Clonal females showed a diversified bet-hedging strategy to spread risk of reproduction in ponds with unpredictable hydroperiod. They adjusted proportion of different egg phenotypes in response to experimental temperature and photoperiod that are proxies for different hydroperiod unpredictability. The proportion of resting eggs is not affected by maternal age at deposition, but mother's age has a key role in defining the development time and the hatching phenology of nonresting eggs. Genetically identical eggs kept at the same controlled laboratory conditions showed a U-shaped distribution of development time. Development time variance decreased with mother's age at deposition. The resulting wedge-shaped relationship between development time and mother's age at deposition may be interpreted by considering mother's age as a proxy for the probability of drought onset. The older the mother, the shorter the latency to drought and the shorter is the time for nonresting eggs to hatch. Considering only the delayed development of eggs that hatch synchronously, development time is inversely related to the mother's age at deposition: this relationship generates the observed hatching peak.

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“…This species is an omnivore, eating both dead and living material (Henderson, ) including C. diaphanus . It occurs in saline and freshwater habitats worldwide, including temporary waterbodies (Henderson, ; Rossi et al ., ). It hatches from cysts laid in the substratum (Boix, Sala & Moreno‐Amich, ), the time taken to develop also being dependent upon temperature (Henderson, ).…”

Section: Methodsmentioning

confidence: 99%

Climate change and trophic interactions in model temporary pond systems: the effects of high temperature on predation rate depend on prey size and density

2013

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1. Climatic warming has induced marked shifts in the geographical distribution and seasonal phenology of many species, although the impacts of climatic changes on the interactions between species across trophic levels are far less well known. 2. Freshwater microcosms were used to test the effect of temperature on the life history traits of a prey species, the fairy shrimp Chirocephalus diaphanus (Anostraca), the abundance of a predator, the microcrustacean Heterocypris incongruens (Ostracoda), and on the interaction between them. 3. When reared in the absence of predators, C. diaphanus survival was low at the highest temperature (25°C) and greatly reduced at the lowest temperature (5°C). It was reproductively most successful at an intermediate temperature (20°C), suggesting that it may benefit from the increase in temperature predicted under future climate change scenarios. In the absence of other species, temperature would have to increase dramatically to affect C. diaphanus adversely. 4. Heterocypris incongruens was more abundant and its predation on C. diaphanus greatest at higher temperatures, partially offsetting the positive effect of raised temperature on prey observed when the predator was absent. The net effect was that the optimal temperature for C. diaphanus when coexisting with its predator was lower than when it was in isolation. This means that currently predicted increases in temperature ultimately may be detrimental to C. diaphanus. 5. Predation rates were generally enhanced by high temperature, prey size and prey density, with significant interaction between them. Thus, the positive effects of raised temperature on predation rate were additionally dependent upon prey characteristics, being strongest when prey were large and at high density and weakest when prey were small and at low density. 6. Interactions with a natural enemy, in this case a predator, may alter how species respond to raised temperatures; prey size and density further modify the outcome of this interaction. This context dependency in the response of both predators and prey to temperature suggests that the ecological impacts of future climate change on trophic interactions may be difficult to predict.

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Heterocypris(Crustacea: Ostracoda) from the Isole Pelagie (Sicily, Italy): Hatching phenology of resting eggs

Cited by 22 publications

References 48 publications

Experimental assessment of the fecundity of Eucypris virens (Ostracoda, Crustacea) under natural sex ratios

Experimental assessment of the fecundity of Eucypris virens (Ostracoda, Crustacea) under natural sex ratios

Mother's Age and Hatching Phenology Strategy ofHeterocypris incongruens(Crustacea: Ostracoda) in Unpredictable Environment

Climate change and trophic interactions in model temporary pond systems: the effects of high temperature on predation rate depend on prey size and density

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