Hatching Size Research Articles

The effects of nurse eggs and sibling interactions on the larval development of the poecilogonous annelid Boccardia proboscidea (Spionidae)

AbstractIn poecilogony, different types of larvae are produced within the same species. Previous studies have suggested maternal control of the production of larval types; however, it is not clear which factors or mechanisms generate contrasting developmental patterns among siblings. The spionid polychaete Boccardia proboscidea produces within the same capsule adelphophagic larvae that eat nurse eggs and siblings and complete all or most of their development inside the capsule (Type A larvae), and larvae with little growth until they hatch as planktotrophic larvae (Type B larvae). In this study, we manipulated capsule content to explore the factors determining larval type in B. proboscidea and the role of extra‐embryonic maternal nutrition and sib–sib interaction in the developmental fate of offspring. When early larval stages were grown individually in vitro, with nurse eggs as the only food source, some of them remained small, while others continue developing into larger pre‐competent larvae by feeding on nurse eggs. This suggests that larval types in B. proboscidea are determined very early in development and are not solely the product of sib–sib interaction inside the capsule. However, our data also suggest that hatching size variability within larval types of a clutch depends on nurse egg availability. Type B larvae grew normally to metamorphosis when phytoplankton was available, but suffered high rates of cannibalism by Type A larvae. These results are consistent with the hypothesis that individual larval fates are determined very early in development and that once their fate is determined, hatching size and intracapsular survival are affected by maternal food provisioning and sibling interaction.

Phylogenetics of the gastropod genus Nucella (Neogastropoda: Muricidae): species identities, timing of diversification and correlated patterns of life-history evolution

Despite the importance of Nucella as a model system in numerous fields of biology, no phylogenetic analysis of the genus, including every widely recognized species, has been conducted. We have analysed about 4,500 bp of DNA from six different genes (three mitochondrial, three nuclear) from each taxon in the genus. Our results showed western Pacific N. heyseana and N. freycinetii as distinct and distantly related, but found no evidence that N. elongata is distinct from N. heyseana .W e also resolved N. heyseana as the closest living relative of the North Atlantic N. lapillus and, using the fossil record for calibration, inferred a minimum separation time between Atlantic and Pacific lineages of at least 6.2 Ma, slightly pre-dating the opening of the Bering Strait. Comparative analyses showed egg size to be evolutionarily labile, but also revealed a highly significant negative relationship between egg size and the nurse-egg-to-embryo ratio. The negative correlation indicates that evolutionary changes in egg size among species are balanced by changes in the number of nurse eggs allocated to each offspring, indicating that interspecific variation in the nurse-egg-to-embryo ratio has not been driven by divergent selection on hatching size, but may instead be a response to variation in other factors, such as parent-offspring conflict.

Genetic, morphological, and life history traits variation in freshwater snails from extremely high environments of the Andean Altiplano

The isolated watersheds of the southwestern Andean Altiplano constitute a natural laboratory to study the evolutionary divergence of freshwater biota. Field observations showed that Biomphalaria snails from Parinacota, Colpa, and Caquena have different shell sizes. We performed morphometric analysis and common garden experiment to evaluate whether the observed shell variation has a genetic base and if this variation is manifested in other morphological characters and life history traits. Network analysis revealed that the snails of Parinacota form a lineage genetically distinct from Caquena and Colpa. The morphometric analysis of the shell showed that the Parinacota snails were larger than Caquena and Colpa, both in nature and laboratory conditions, but there was no evidence of difference in the shape of the shell when compared using multivariate analyses. The number of eggs per ovicapsule was the only life history trait that was significantly different between lineages, although this difference may be also attributed to size of the progenitor; the oviposition rate did not differ between lineages or localities, and the hatching size and growth rate differed only at the locality level, not lineages. The results suggest that shell size of the snails has a genetic basis associated to the phenotype, while the expression and evolution of life history traits in extreme high environments are highly influenced by proximal causes.

Effects of ocean acidification on hatch size and larval growth of walleye pollock (Theragra chalcogramma)

Abstract Hurst, T. P., Fernandez, E. R., and Mathis, J. T. 2013. Effects of ocean acidification on hatch size and larval growth of walleye pollock (Theragra chalcogramma). – ICES Journal of Marine Science, 70: 812–822. Rising atmospheric concentrations of CO2 are predicted to decrease the pH of high-latitude oceans by 0.3–0.5 units by 2100. Because of their limited capacity for ion exchange, embryos and larvae of marine fishes are predicted to be more sensitive to elevated CO2 than juveniles and adults. Eggs and larvae of walleye pollock (Theragra chalcogramma) were incubated across a broad range of CO2 levels (280–2100 µatm) to evaluate sensitivity in this critical resource species. Slightly elevated CO2 levels (∼450 µatm) resulted in earlier hatching times, but differences among egg batches were greater than those observed across CO2 treatments. Egg batches differed significantly in size-at-hatch metrics, but we observed no consistent effect of CO2 level. In three independent experiments, walleye pollock were reared at ambient and elevated CO2 levels through the early larval stage (to ∼30 days post-hatch). Across trials, there were only minor effects of CO2 level on size and growth rate, but fish in the ambient treatments tended to be slightly smaller than fish reared at elevated CO2 levels. These results suggest that growth potential of early life stages of walleye pollock is resilient with respect to the direct physiological effects of ocean acidification.

Impacts of Adelphophagic Development on Variation in Offspring Size, Duration of Development, and Temperature-Mediated Plasticity

Adelphophagic development, where embryos consume sibling embryos or nurse eggs, is particularly common in marine caenogastropods and some families of polychaetes. When exogenous nutrition is provided before hatching, egg size and hatching size can be uncoupled, but advantages and constraints of adelphophagic development compared to development from large eggs are unknown. Here we examine temperature-mediated plasticity in offspring size, brooding duration, and fecundity in the adelphophagic marine gastropod Crepidula cf. onyx. We use these data combined with previously published data on two planktotrophic Crepidula and two Crepidula species that develop from large eggs to test hypotheses about the consequences of adelphophagic development and patterns of variation in offspring size. In Crepidula cf. onyx, egg size shows no significant effect of temperature. Hatching size is significantly larger at 28 °C than at 23 °C but proceeds from fewer eggs per capsule at 28 °C. Hatching size is therefore decoupled from both egg size and the number of eggs per capsule. Although development is faster at the higher temperature, broods are produced roughly every 26-27 days at both temperatures. Increased rate of development has been cited as a potential advantage of adelphophagic development in muricids, but the adelphophagic C. cf. onyx did not develop more quickly than C. atrasolea or C. ustulatulina, species that produce similarly sized hatchlings from large eggs. Comparisons across calyptraeid species support the role of adelphophagy in increasing variance in offspring size. This increased variability is primarily expressed within broods or among broods from the same female, not among females.

Temperature-mediated trade-offs and changes in life-history integration in two slipper limpets (Gastropoda: Calyptraeidae) with planktotrophic development

Intraspecific variation in egg size and hatching size, and the genetic and environmental trade-offs that contribute to variation, are the basis of the evolution of life histories. The present study examined both univariate and multivariate temperature-mediated plasticity of life-history traits, as well as temperature-mediated trade-offs in egg size and clutch size, in two planktotrophic species of marine slipper limpets, Crepidula. Previous work with two species of Crepidula with large eggs and lecithotrophic development has shown a significant effect of temperature on egg size and hatching size. To further examine the effect of temperature on egg size in Crepidula, the effects of temperature on egg size and hatching size, as well as the possible trade-offs with other the life-history features, were examined for two planktotrophic species: Crepidula incurva and Crepidula cf. marginalis. Fieldcollected juveniles were raised at 23 or 28 °C and egg size, hatching size, capsules/brood, eggs/capsule, time to hatch, interbrood interval, and final body weight were recorded. Consistent with results for the lecithotrophic Crepidula, egg size and hatching size decreased with temperature in the planktotrophic species. The affects of maternal identity and individual brood account for more than half of the intraspecific variation in egg size and hatching size. Temperature also showed a significant effect on reproductive rate, with time to hatch and interbrood interval both decreasing with increasing temperature. However, temperature had contrasting effects on the number of offspring. Crepidula cf. marginalis has significantly more eggs/capsule and therefore more eggs per brood at 28 °C compared to 23 °C, although capsules/brood did not vary with temperature. Crepidula incurva, on the other hand, produced significantly more capsules/brood and more eggs per brood at the lower temperature, whereas the number of eggs/capsule did not vary with temperature. The phenotypic variance‐covariance matrix of life-history variables showed a greater response to temperature in C. incurva than in C. cf. marginalis, and temperature induced trade-offs between offspring size and number differ between the species. These differences suggest that temperature changes as a result of seasonal upwelling along the coast of Panama will effect the reproduction and evolution of life histories of these two co-occurring species differently. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, , ••‐••. ADDITIONAL KEYWORDS: adaptive phenotypic plasticity ‐ phenotypic covariance ‐ P-matrix ‐ temperature-size rule.

Some biological characteristics of early larvae Dacodraco hunteri (Notothenioidei: Channichthyidae) in the western Ross Sea

Ichtyoplankton surveys were carried out in the western Ross Sea by the R/V Italica in the austral summer 1996 and 1997–1998 to study species composition and spatial distribution of larval stages of fish. One of the most abundant icefish caught was Dacodraco hunteri, a poorly known channichthyid inhabiting the high-Antarctic Zone. Based on 382 yolk-sac larvae and 13 preflexion larvae, the study was focused to estimate spatial distribution and abundance, as well as diet and growth rate. The pigmentation pattern and some morphometric measurements were also recorded for comparative purposes. The specimens were caught in relatively restricted areas located in Terra Nova Bay and north of the Ross Ice Shelf on the Challenger and Joides Basins. The standardized abundance of early larvae ranged between 0.03 and 1.72 individuals 10−3 m3 in 1996 and 0.16–4.53 individuals 10−3 m3 in 1997–1998, respectively. Fitting a linear model to the mean length increase in larvae collected in subsequent catch dates, the growth rate was estimated to be approximately 0.11 mm/day. Based on back calculation of growth rate and presumed hatch size of 11 mm, larval hatching probably took place in mid-December. Diet of preflexion larvae consisted exclusively of larvae of the pelagic nototheniid Pleuragramma antarcticum, a key species of the high-Antarctic pelagic food web. Hence, D. hunteri probably plays a more important role than previously thought in the pelagic community of the Ross Sea.

Larval ecology of the great barracuda, Sphyraena barracuda, and other sphyraenids in the Straits of Florida

The great barracuda (Sphyraena barracuda) is a widespread, ecologically and socioeconomically important coastal fish, yet very little is known about its larvae. We examined spawning and larval ecology of Western Atlantic sphyraenids using monthly ichthyoplankton samples collected over 2 years along a transect spanning the east–west axis of the Straits of Florida (SOF). Samples were dominated by the great barracuda (92.8%) and sennets (Sphyraena borealis and Sphyraena picudilla; 6.6%). While larval sennets and S. barracuda displayed similar vertical distributions (majority in upper 25 m), horizontal and temporal patterns of abundance suggested a spatial and temporal species replacement between larval S. barracuda and sennets that tracks adult ecology. The diet of both taxa consisted largely of copepods, with inclusion of fish larvae at 8 mm SL, and in S. barracuda alone, a switch in the wet season to exclusive piscivory by 12 mm SL (18 days post-hatch). A lack of piscivory in S. barracuda larvae captured in the dry season corresponded to slower larval growth than in the wet season. Larval growth was also related to size-at-hatch and larval age such that larvae that were larger at hatch or larger (older) at capture grew faster at earlier ages, suggesting faster larval growth, and indirectly larger hatch size, conveys a survival advantage. Unlike larval growth, instantaneous mortality rate did not differ with season, and no lunar cyclic patterns in spawning output were identified. Our results provide insight into the pelagic phase of sphyraenids and highlight the importance of both diet and hatch size to the growth and survival of fish larvae in low latitude oceanic environments.

E0570 Can hatch score predict recurrence of atrial fibrillation after catheter ablation?

BackgroundHATCH score (1*hypertention+1*[age>75]+2*[stroke or transient ischaemic attack]+1*[chronic obstructive pulmonary disease]+2* [heart failure]) is an established predictor of progression from paroxysmal to persistent atrial fibrillation (AF). Whether atrial remodelling indexed by...

GLMM-based modelling of growth in juvenile Octopus maya siblings: does growth depend on initial size?

Abstract Briceño, F., Mascaró, M., and Rosas, C. 2010. GLMM-based modelling of growth in juvenile Octopus maya siblings: does growth depend on initial size? – ICES Journal of Marine Science, 67: 1509–1516. In most studies on cephalopod growth, variability in initial size is masked by the assumption of a similar growth “starting point” for all hatchlings and by calculating the growth rate (GR) through modelling the average size of individuals through time. Statistical interpretations based on such models are limited because regression assumptions (e.g. homoscedasticity and independence between subjects) are frequently violated. To avoid these limitations, generalized linear mixed modelling was used to model the early growth of two sets of siblings of the holobenthic octopus Octopus maya under controlled conditions. The aim was to (i) determine the effect of initial weight (IW) on the GR of individuals grouped in three size categories (small, medium, and large), (ii) obtain statistically reliable estimates of parameters in an exponential growth model for juveniles up to 105 d old, and (iii) evaluate the influence of hatching date on weight at hatching. Using restricted maximum likelihood, linear models were fitted between (i) IW and final weight (FW) for octopuses in each size category, and (ii) the natural logarithm of IW as a function of time. The models were validated by visually inspecting the residuals. Individual FW depended on IW, but GR did not differ between juveniles of different sizes. The exponential growth model for individuals of all size categories was, with εi ∼ N(0,σ2 [agei]2δ). Hatching date had no effect on hatching size (F = 1.93; p = 0.11). The GR value is similar to those reported for other holobenthic species, and one of the first estimates of the magnitude (δ = 0.20) and structure of the increase in variance of individual weight through time is provided.

Eggshell characteristics and yolk composition in the common cuckoo Cuculus canorus: are they adapted to brood parasitism?

The developmental rate of cuckoo embryos and their hatching size is greater than that of host species, which may require more nutrient resources in the egg and more intensive gas exchange during development. In the present study, we compared various egg characteristics of a brood parasite, the common cuckoo Cuculus canorus, and its frequent host, the great reed warbler Acrocephalus arundinaceus. As maternally‐derived testosterone is known to enhance growth rate of embryos and hatchlings, cuckoo eggs are expected to contain higher concentration of testosterone than host eggs. In addition, we expected higher concentration of antioxidants in cuckoo eggs to protect embryos from oxidative stress associated with accelerated growth. Our results showed that cuckoo eggs had thicker shells and higher pore density than great reed warbler eggs. Yolk was significantly heavier in cuckoo eggs and contained higher concentrations of carotenoids and vitamin E, however, yolk androgen and immunoglobulin concentrations were lower in cuckoo eggs as compared to great reed warbler eggs. We also examined whether eggshell colour was associated to egg quality, and detected a positive association between blue‐green chroma and yolk antioxidant concentration in both species, suggesting that eggshell colour reflects the antioxidant investment of the female into the eggs. Our results suggest that cuckoo females increase the size, growth rate and competitive ability of their young by providing them with more nutrients and more dietary antioxidants for embryonic development, and not through elevated yolk testosterone or antibody levels. In addition, increased porosity of cuckoo eggshells may allow embryos to develop more rapidly because of a greater capacity of gas exchange.

Growth, hatch size and maturation in a southern population of the loliginid squidLoliolus noctiluca

Age, growth and cost of reproduction were examined for the small near-shore loliginid squidLoliolus noctilucain Tasmanian waters, near the southern limit of its distribution. The effects of several factors on hatch size were also evaluated by comparing the statolith natal ring size (NR) from individuals collected in different locations, seasons and years. The life cycle ofL. noctilucawas less than six months. July-hatched females grew faster than their May-hatched counterparts, indicating a faster growth in winter-hatched compared with autumn-hatched individuals. There was considerable variation in NRs as function of location, season, year and sex, with females displaying NRs considerably larger than males in any location and year. Immature and maturing females displayed poorer body condition than mature counterparts, suggesting that gonad growth does not affect the mantle or fin growth. A good condition was maintained also in spent individuals indicating thatL. noctilucacontinued to invest in somatic organs throughout the spawning period. A reproductive strategy closer to ‘multiple spawning’, than to ‘single spawning’ was proposed for this species.Loliolus noctilucawas used as a model to explore the possible effects of climate change on near-shore loliginid populations.

Temperature-mediated plasticity and genetic differentiation in egg size and hatching size among populations of Crepidula (Gastropoda: Calyptraeidae)

Offspring size is a key characteristic in life histories, reflecting maternal investment per offspring and, in marine invertebrates, being linked to mode of development. Few studies have focused explicitly on intraspecific variation and plasticity in developmental characteristics such as egg size and hatching size in marine invertebrates. We measured over 1000 eggs and hatchlings of the marine gastropods Crepidula atrasolea and Crepidula ustulatulina from two sites in Florida. A common-garden experiment showed that egg size and hatching size were larger at 23 °C than at 28 °C in both species. In C. ustulatulina, the species with significant genetic population structure in cytochrome oxidase I (COI), there was a significant effect of population: Eggs and hatchlings from the Atlantic population were smaller than those from the Gulf. The two populations also differed significantly in hatchling shape. Population effects were not significant in C. atrasolea, the species with little genetic population structure in COI, and were apparent through their marginal interaction with temperature. In both species, 60‐65% of the variation in egg size and hatching size was a result of variation among females and, in both species, the population from the Atlantic coast showed greater temperature-mediated plasticity than the population from the Gulf. These results demonstrate that genetic differentiation among populations, plastic responses to variation in environmental temperature, and differences between females all contribute significantly to intraspecific variation in egg size and hatching size. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 489‐499. ADDITIONAL KEYWORDS: evolution of development ‐ maternal effects ‐ offspring size ‐ phylogeography.

Size at hatching determines population dynamics and response to harvesting in cannibalistic fish

We hypothesize that size at hatching strongly affects population dynamics of cannibalistic fish species and is a crucial determinant of how populations respond to selective removal of large individuals (harvesting). We use a mechanistic mathematical model to study the relation between hatching size and response to harvesting mortality, using Eurasian perch ( Perca fluviatilis ) as a model organism. We show how hatching size determines dynamics through its effect on the relative strength of cannibalistic mortality and resource competition as mechanisms of population regulation. In populations with intermediate and large hatching size, cannibalistic mortality is an important determinant of population dynamics, and harvesting destabilizes population dynamics. When hatching size is small, population stability is less sensitive to this type of harvesting. Populations hatching at small size are regulated by competition, and harvesting large individuals affects such populations less. Harvesting can also induce the growth of very large individuals, absent in unharvested populations. Our results show that harvesting in cannibalistic lake fish populations can strongly alter population dynamics in ways that can only be anticipated on the basis of mechanistic knowledge about how populations are regulated.

Intergenomic epistasis causes asynchronous hatch times in whitefish hybrids, but only when parental ecotypes differ

Support for the theory of ecological speciation requires evidence for ecological divergence between species which directly or indirectly causes reproductive isolation. This study investigates effects of ecological vs. genetic disparity of parental species on the presence of endogenous selection (deformation and mortality rates) and potential sources of exogenous selection (growth rates and hatch timing) on hybrids. Hybrid embryonic development is analysed in a common-garden full-sib cross of three species belonging to two different ecotypes within the Coregonus lavaretus species flock in the central Alpine region of Europe. Although hatch timing was similar across the three species, embryonic growth rates and egg sizes differed between ecotypes. This led to a mismatch between embryonic growth rate and egg size in hybrid crosses that reveals epistasis between the maternal and embryonic genomes and transgressive hatch times that were asynchronous with control crosses. A strong constraint of egg size to embryo size at late development was also evident. We argue that this demonstrates potential for coadaptation of a maternal trait (egg size) with offspring growth rate to be an important source of selection against hybridization between ecotypes with different egg sizes. Implications for the measurement and quantification of early life-history traits affected by this additive relationship, such as hatch day and larval size, are also discussed.

Egg production of two sympatric species of Hyalella Smith, 1874 (Crustacea, Amphipoda, Dogielinotidae) in aquaculture ponds in southern Brazil

This study tests the hypothesis that sympatric species of Hyalella may show different reproductive strategies that permit their coexistence. Ovigerous females were collected monthly with nets during a 1-year period in two aquaculture trout ponds in Vale das Trutas, São José dos Ausentes County, southern Brazil. In both species there was a decrease in the number of embryos in the brood pouch during embryonic development, and an increase in egg volume. However, the two species differed in the body size of ovigerous females, number of eggs and juveniles per female, brood mortality rate, egg size and hatching size of juveniles. Egg production continued throughout the year, with the highest number of eggs produced during winter and spring by Hyalella pleoacuta, and winter, spring and autumn by Hyalella castroi. These differences in the reproductive traits of species of Hyalella may permit their coexistence in nature.

Ontogenetic Mechanisms Underlying a Geographic Size Cline in a Grasshopper, Romalea microptera

Abstract Geographic clines in body size have been described for many species, but relatively few investigations have tested hypotheses for the ontogenetic mechanisms maintaining geographic clines. We formalize and test the predictions for the role of ontogenetic mechanisms (e.g., hatching timing and size, juvenile developmental time, juvenile growth rate) in maintaining a longitudinal cline in adult body size of lubber grasshoppers [Romalea microptera (Beauvois)]. To obtain hatching timing and size, we collected eggs from wild females from several populations along the longitudinal gradient in 2 yr (2006 and 2007) and measured hatchling size and hatch date. To obtain juvenile developmental time and growth rates, we surveyed populations along the longitudinal gradient during 2 yr (2006 and 2007) and estimated developmental time and growth rates. We found the developmental time (hatching to fourth instar) and female growth rates increase from west to east along the cline. Patterns of hatching timing and hatching size were not consistent with the size cline. The size cline becomes evident in the third instar and is magnified in the fourth and fifth instars. Our data suggest that the size cline arises from some combination of clinal variation in developmental time and female growth rates; prolonged development and greater growth rates lead to larger mean size. Equally important, we found no evidence that differences in hatching time or size are ontogenetic causes of this cline. Our hypotheses for ontogenetic mechanisms producing an adult size cline should serve as a template for ecologists seeking to understand the ontogenetic basis of spatial variation in phenotypes.

Effects of potential predator and competitor cues and sibship on wood frog (Rana sylvatica) embryos

Abstract Chemical cues emitted from predators or competitors are often important for animals living in aquatic ecosystems as they allow potential prey to assess predation risk and make appropriate risk-sensitive responses. In our experiment, we examined if wood frog (Rana sylvatica) embryos exposed to potential predator and competitor cues would alter their time to hatching, size at hatching, or survivorship. Eggs from four different sibships were subjected to a variety of cues including dragonfly larvae (potential tadpole predator), mosquitofish (Gambusia affinis; a non-native potential egg and tadpole predator), and overwintered tadpoles of Rana sp. (potential competitors). We found no significant effects of any of the cues. However, we did find significant variation in mean time to hatching and mean hatchling size among sibships. Our results suggest that wood frog embryos may have limited ability to respond to some cues at the embryonic stage, at least for the concentrations and conditions used in this experiment. Our results do indicate genetic or parental effects can affect embryonic wood frog development rate and hatchling size.

Hatch Size Evaluation for the Altair Lunar Sortie Habitat

Issues of moving through hatchways and related design problems of hatch size and shape were investigated for the Altair lunar habitat. To insure proper usability and safety, the goal of the current study was to understand the critical dimensions necessary for proper translation through the hatch by manipulating size (height, width, step over height, and overall height) and shape (rectangular and circular). A single participant donning a pressurized rear-entry integrated (REI) Extravehicular Activity (EVA) suit was timed and video recorded as participant accomplished various translations through a mockup hatch. Objective performance measures consisted of time and contact data with the hatch, while subjective data was obtained using the Cooper-Harper Qualities Ratings, Corlett and Bishop Discomfort Scale, a Physical Effort scale, and a functionality questionnaire. Correlation analysis discovered a significant relationship between the hatch dimension of height and all of the performance measures, as well as, step over and overall height with some of the dependent scores.

Developmental responses to UV‐B radiation in common frogRana temporariaembryos from along an altitudinal gradient

AbstractSolar ultraviolet radiation (UV) is harmful for developing amphibians. As UV increases with altitude and latitude, it is suggested that high altitude and latitude populations have evolved tolerance to high levels of UV. Using laboratory experiments, we tested the hypothesis thatRana temporariapopulations from several altitudes (438–2,450 m above sea level) were adapted to UV by assessing the effects of artificial UV on embryos mortality rate, malformations, and body length at hatching. We also tested the protective role of the jelly surrounding the embryos. Without artificial UV exposure, hatching success decreased with altitude of the population. Malformation rates were low for all populations (mean 1.36%), and hatching size increased with altitude. The artificial UV (UV‐B, UV‐A, and visible) used was similar to the solar spectrum received at high altitude. Exposed embryos had performance similar to that of embryos without exposure: a decreased hatching success with altitude and a low malformation rate (mean 0.85%). However, hatching size did not vary with altitude, and UV‐exposed embryos tended to be smaller at hatching than non‐exposed embryos. Removal of the protective jelly envelope greatly decreased the performance of UV‐exposed embryos: hatching success strongly decreased with altitude and embryos of the highest population (2,450 m asl) did not develop. Malformation reached 4.98%, without population differences, and hatching size of embryos without jelly was smaller than hatching size of non‐manipulated embryos with no population effect. This study demonstrates that lowland jellyless embryos were less sensitive (i.e., exhibited a higher survival rate) than highland embryos and, on the other hand, that the jelly envelope was a more efficient protection for embryos in highland than in lowland populations. A trade‐off hypothesis is presented to explain this difference in UV tolerance and protection among populations: in a harsh, highland environment (i.e., with a curtailed activity period), embryos have to invest in development and growth and, thus, embryo protection should be a female investment (via the jelly). In a lowland environment, embryonic growth and development are less constrained and embryos are able to invest and use protection or repair mechanisms inherited from their parents.