Flexible dispersal dimorphism in zooplankton resting eggs: an example of repeated phenotypic coin flipping?

Theory predicts that spatio‐temporal variation in habitat suitability will promote selection for dispersal. In addition to movement in space, dispersal gains an extra dimension in freshwater zooplankton because resting eggs can disperse in time as well, via dormancy. Potential trade‐offs between both strategies, however, remain largely unexplored. Using a temporary pool fairy shrimp population as a model, we tested for consistent differences in buoyancy among resting eggs during consecutive inundations in a standardized laboratory experiment and explored a potential trade‐off between dispersal (floaters versus sinkers) and dormancy (high versus low hatching fractions). Although discrete dispersal morphs were present, this trait was not fixed. Irrespective of their dispersal phenotype during previous inundations, floating eggs hatched more frequently than sinking eggs. Egg morphology did not affect buoyancy and, between inundations, approximately half of the eggs changed their dispersal phenotype. Although this mechanism has affinities with conservative bet hedging and adaptive coin flipping, it is unique because the dispersal phenotype can switch at the onset of each inundation. Despite possible selection against dispersal at the population level, such a strategy ensures variation in dispersal ability at any moment and could promote population persistence in a metapopulation context. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110 , 749–756.     

Adaptation in a variable environment: Phenotypic plasticity and bet‐hedging during egg diapause and hatching in an annual killifish

Two ways in which organisms adapt to variable environments are phenotypic plasticity and bet‐hedging. Theory suggests that bet‐hedging is expected to evolve in unpredictable environments for which reliable cues indicative of future conditions (or season length) are lacking. Alternatively, if reliable cues exist indicating future conditions, organisms will be under selection to produce the most appropriate phenotype —that is, adaptive phenotypic plasticity. Here, we experimentally test which of these modes of adaptation are at play in killifish that have evolved an annual life cycle. These fish persist in ephemeral pools that completely dry each season through the production of eggs that can remain in developmental arrest, or diapause, buried in the soil, until the following rainy season. Consistent with diversified bet‐hedging (a risk spreading strategy), we demonstrate that the eggs of the annual killifish Nothobranchius furzeri exhibit variation at multiple levels—whether or not different stages of diapause are entered, for how long diapause is entered, and the timing of hatching—and this variation persists after controlling for both genetic and environmental sources of variation. However, we show that phenotypic plasticity is also present in that the proportion of eggs that enter diapause is influenced by environmental factors (temperature and light level) that vary seasonally. In nature there is typically a large parameter zone where environmental cues are somewhat correlated with seasonality, but not perfectly so, such that it may be advantageous to have a combination of both bet‐hedging and plasticity.     

Costly defense in a fluctuating environment—sensitivity of annual Nothobranchius fishes to predator kairomones

Antipredator strategies increase the chances of survival of prey species but are subject to trade‐offs and always come at a cost, one specific category being the “missed opportunity.” Some animals that can modulate the timing of life‐cycle events can also desynchronize this timing with the occurrence of a predator. In an unpredictable environment, such a modification may result in a mismatch with prevailing conditions, consequently leading to reproductive failure. In eastern Africa, temporary pools existing only during the rainy season are inhabited by annual fish of the genus Nothobranchius. We examined (i) the capability of multiple Nothobranchius populations and species to cease hatching when exposed to chemical cues from native fish predators and adult conspecifics and (ii) the ability of N. furzeri to modulate their growth rate in the presence of a gape‐limited fish predator. As the tested Nothobranchius spp. originate from regions with extreme environmental fluctuations where the cost of a missed opportunity can be serious, we predicted an inability to cease hatching as well as lack of growth acceleration as both the predator's gape limitation and the environment select for the same adaptation. Our results showed no biologically relevant influence of kairomone on hatching and no influence on growth rate. This suggests that, in an unpredictable environment, the costs of a missed opportunity are substantial enough to prevent the evolution of some antipredator defense strategies.     

Alternative intrapopulation life‐history strategies and their trade‐offs in an African annual fish

In ephemeral habitats, the same genotypes cope with unpredictable environmental conditions, favouring the evolution of developmental plasticity and alternative life‐history strategies (ALHS). We tested the existence of intrapopulation ALHS in an annual killifish, Nothobranchius furzeri, inhabiting temporary pools. The pools are either primary (persisting throughout the whole rainy season) or secondary (refilled after desiccation of the initial pool), representing alternative niches. The unpredictable conditions led to the evolution of reproductive bet‐hedging with asynchronous embryonic development. We used a common garden experiment to test whether the duration of embryonic period is associated with post‐embryonic life‐history traits. Fish with rapid embryonic development (secondary pool strategy, high risk of desiccation) produced phenotypes with more rapid life‐history traits than fish with slow embryonic development (primary pool strategy). The fast fish were smaller at hatching but had larger yolk sac reserves. Their post‐hatching growth was more rapid, and they matured earlier. Further, fast fish grew to a smaller body size and died earlier than slow fish. No differences in fecundity, propensity to mate or physiological ageing were found, demonstrating a combination of plastic responses and constraints. Such developmentally related within‐population plasticity in life history is exceptional among vertebrates.     

Aberrant clones: Birth order generates life history diversity in Greater Duckweed,Spirodela polyrhiza

Environmental unpredictability is known to result in the evolution of bet‐hedging traits. Variable dormancy enhances survival through harsh conditions, and is widely cited as a diversification bet‐hedging trait. The floating aquatic plant, Spirodela polyrhiza (Greater Duckweed), provides an opportunity to study diversification because although partially reliable seasonal cues exist, its growing season is subject to an unpredictable and literally “hard” termination when the surface water freezes, and overwinter survival depends on a switch from production of normal daughter fronds to production of dense, sinking “turions” prior to freeze‐over. The problem for S. polyrhiza is that diversified dormancy behavior must be generated among clonally produced, genetically identical offspring. Variation in phenology has been observed in the field, but its sources are unknown. Here, we investigate sources of phenological variation in turion production, and test the hypothesis that diversification in turion phenology is generated within genetic lineages through effects of parental birth order. As expected, phenotypic plasticity to temperature is expressed along a thermal gradient; more interestingly, parental birth order was found to have a significant and strong effect on turion phenology: Turions are produced earlier by late birth‐order parents. These results hold regardless of whether turion phenology is measured as first turion birth order, time to first turion, or turion frequency. This study addresses a question of current interest on potential mechanisms generating diversification, and suggests that consistent phenotypic differences across birth orders generate life history variation.     

Spatially heterogeneous stochasticity and the adaptive diversification of dormancy

Diversified bet‐hedging, a strategy that leads several individuals with the same genotype to express distinct phenotypes in a given generation, is now well established as a common evolutionary response to environmental stochasticity. Life‐history traits defined as diversified bet‐hedging (e.g. germination or diapause strategies) display marked differences between populations in spatial proximity. In order to find out whether such differences can be explained by local adaptations to spatially heterogeneous environmental stochasticity, we explored the evolution of bet‐hedging dormancy strategies in a metapopulation using a two‐patch model with patch differences in stochastic juvenile survival. We found that spatial differences in the level of environmental stochasticity, restricted dispersal, increased fragmentation and intermediate survival during dormancy all favour the adaptive diversification of bet‐hedging dormancy strategies. Density dependency also plays a major role in the diversification of dormancy strategies because: (i) it may interact locally with environmental stochasticity and amplify its effects; however, (ii) it can also generate chaotic population dynamics that may impede diversification. Our work proposes new hypotheses to explain the spatial patterns of bet‐hedging strategies that we hope will encourage new empirical studies of this topic.     

Not putting all their eggs in one basket: bet‐hedging despite extraordinary annual reproductive output of desert tortoises

Bet‐hedging theory makes the counter‐intuitive prediction that, if juvenile survival is low and unpredictable, organisms should consistently reduce short‐term reproductive output to minimize the risk of reproductive failure in the long‐term. We investigated the long‐term reproductive output of an Agassiz's desert tortoise (Gopherus agassizii) population and conformance to a bet‐hedging strategy of reproduction in an unpredictable but comparatively productive environment. Most females reproduced every year, even during periods of low precipitation and poor germination of food plants, and the mean percentage of reproducing females did not differ significantly on an annual basis. Although mean annual egg production (clutch size × clutch frequency) differed significantly among years, mean clutch size and mean clutch frequency remained relatively constant. During an El Niño year, mean annual egg production and mean annual clutch frequency were the highest ever reported for this species. Annual egg production was positively influenced by maternal body size but clutch size and clutch frequency were not. Our long‐term results confirm earlier conclusions based on short‐term research that desert tortoises have a bet‐hedging strategy of producing small clutches almost every year. The risk of long‐term reproductive failure is minimized in unpredictable environments, both through time by annually producing multiple small clutches over a long reproductive lifespan, even in years of low resource availability, and through space by depositing multiple annual clutches in different locations. The extraordinary annual reproductive output of this population appears to be the result of a typically high but unpredictable biomass of annual food plants at the site relative to tortoise habitat in dryer regions. Under the comparatively productive but unpredictable conditions, tortoises conform to predictions of a bet‐hedging strategy of reproduction with relatively small but consistent clutch sizes. Published 2015. This article is a U.S. Government work and is in the public domain in the USA, Biological Journal of the Linnean Society, 2015, 115 , 399–410.     

Squeezing out the last egg—annual fish increase reproductive efforts in response to a predation threat

Both constitutive and inducible antipredator strategies are ubiquitous in nature and serve to maximize fitness under a predation threat. Inducible strategies may be favored over constitutive defenses depending on their relative cost and benefit and temporal variability in predator presence. In African temporary ponds, annual killifish of the genus Nothobranchius are variably exposed to predators, depending on whether larger fish invade their habitat from nearby rivers during floods. Nonetheless, potential plastic responses to predation risk are poorly known. Here, we studied whether Nothobranchius furzeri individuals adjust their life history in response to a predation threat. For this, we monitored key life history traits in response to cues that signal the presence of predatory pumpkinseed sunfish (Lepomis gibbosus). While growth rate, adult body size, age at maturation, and initial fecundity were not affected, peak and total fecundity were higher in the predation risk treatment. This contrasts with known life history strategies of killifish from permanent waters, which tend to reduce reproduction in the presence of predators. Although our results show that N. furzeri individuals are able to detect predators and respond to their presence by modulating their reproductive output, these responses only become evident after a few clutches have been deposited. Overall our findings suggest that, in the presence of a predation risk, it can be beneficial to increase the production of life stages that can persist until the predation risk has faded.     

Bet‐hedging germination in annual plants: a sound empirical test of the theoretical foundations

Seed dormancy is thought to be a key mechanism allowing annual plants to spread extinction risk in unpredictably varying environments. Theory predicts increasing germination fractions with increasing probability of reproductive success but solid empirical evidence is scarce and often confounded with environmental factors. Here we provide an empirical test of bet‐hedging via delayed germination for three annual plant species along a ‘predictability gradient’ in Israel. We excluded confounding environmental and maternal effects by raising inbred seed families and germinating them under controlled conditions. Additionally, we germinated field‐collected seeds in three consecutive seasons to compare their germination with inbred families where maternal effects were removed. Risk of reproductive failure was quantified using demographic data from the field and from second‐generation inbred lines raised in a rainfall gradient in the greenhouse. Our findings were consistent with bet‐hedging theory in that germination fraction was negatively related to species‐ and site‐specific risk of reproductive failure. Both field and hand‐raised seeds of one species exhibited higher dormancy with increasing risk of reproductive failure across sites, and hand‐raised seeds of another species showed the same pattern. The third species exhibited a rather random pattern of germination between years and sites, corresponding to the lack of site‐specific risk of reproductive failure. Species‐specific patterns of dormancy and risk could be related to alternative risk‐spreading strategies such as high adult survival, but were also affected by phylogeny. We provide strong empirical evidence for seed dormancy being a mechanism to reduce the risk of reproductive failure in highly variable environments, but a larger number of rigorous experimental tests of bet hedging germination are needed. Specifically, the genetic basis of bet‐hedging must be shown in species with different life histories, for demonstrating that dormancy is adaptive and how it is modified by other risk‐spreading traits.     

Local variation in embryo development rate in annual fish

Extreme asynchrony in embryo development, a typical feature of annual killifish living in temporary pools, represents a bet‐hedging strategy to cope with unpredictable rainfall. African annual killifish are distributed across a large precipitation gradient, raising the potential for local adaptation in the degree of developmental asynchrony (e.g. higher in arid areas, lower in humid areas). Eight populations of two sister species, Nothobranchius furzeri and Nothobranchius kadleci, from sites along the rainfall gradient were tested and compared for asynchrony and duration of embryo development. Degree of asynchrony and mean duration of embryo development did not differ across the examined range. Despite generally high developmental variability, fish from more arid regions (where rain is more erratic) produced a significantly higher proportion of short‐developing embryos. Comparable developmental asynchrony, regardless of precipitation level, suggests that all populations tested need to cope with some level of rainfall stochasticity. By producing more short‐developing embryos, however, fish in more arid areas with relatively more erratic rains are better adapted to very short pool durations and are more likely to produce multiple offspring generations within a single rainy season.     

Maternal source of variability in the embryo development of an annual killifish

Organisms inhabiting unpredictable environments often evolve diversified reproductive bet‐hedging strategies, expressed as production of multiple offspring phenotypes, thereby avoiding complete reproductive failure. To cope with unpredictable rainfall, African annual killifish from temporary savannah pools lay drought‐resistant eggs that vary widely in the duration of embryo development. We examined the sources of variability in the duration of individual embryo development, egg production and fertilization rate in Nothobranchius furzeri. Using a quantitative genetics approach (North Carolina type II design), we found support for maternal effects rather than polyandrous mating as the primary source of the variability in the duration of embryo development. The number of previously laid eggs appeared to serve as an internal physiological cue initiating a shift from rapid‐to‐slow embryo developmental mode. In annual killifish, extensive phenotypic variability in progeny traits is adaptive, as the conditions experienced by parents have limited relevance to the offspring generation. In contrast to genetic control, with high phenotypic expression and heritability, maternal control of traits under natural selection prevents standing genetic diversity from potentially detrimental effects of selection in fluctuating environments.     

Experimental evolution of bet hedging in rotifer diapause traits as a response to environmental unpredictability

The adaptive response of organisms to unpredictable environments is increasingly recognized as a central topic in fundamental and applied evolutionary ecology. Selection due to environmental unpredictability can act on multiple traits of an organism's life cycle to reduce the impact of high environmental variance. The aim of this research was to study how unpredictability selects for diapause traits: 1) the timing of sex (a proxy of the timing of diapausing egg production), and 2) the diapausing egg hatching fraction (a proxy of diapause duration). We used an experimental evolution approach with the facultative sexual rotifer Brachionus plicatilis. Laboratory populations experiencing two contrasting regimes of environmental fluctuation (predictable versus unpredictable) evolved divergently over a short time span (< 77 days). The populations under the unpredictable regime showed an earlier initiation of sexual reproduction and a lower hatching fraction of diapausing eggs than populations under the predictable regime. These findings demonstrate empirically the existence of bet‐hedging strategies in B. plicatilis regarding both traits, consistent with theoretical predictions of bet‐hedging evolution under conditions of unpredictable environmental variance. Given that scenarios of increased environmental variability are expected to occur in the near future, a comprehensive understanding of the role of bet‐hedging strategies is necessary for predicting population responses to environmental change.     

Hatching phenology,life history and egg bank size of fairy shrimp Branchipodopsis spp. (Branchiopoda,Crustacea) in relation to the ephemerality of their rock pool habitat

In temporary aquatic habitats, permanence and the severe disturbance associated with desiccation are strong selective agents expected to lead to differentiation in life history strategies in populations experiencing different disturbance regimes. Besides optimal timing of hatching of dormant life stages, maturation and reproduction, pool inhabitants also benefit from the acquisition of reliable cues for the quality of the ambient environment. We investigated whether hatching patterns, life history characteristics and egg bank size of Branchipodopsis fairy shrimp (Branchiopoda, Anostraca) inhabiting a cluster of temporary rock pools in South Africa reflect variation in habitat stability and hatching cues. Long-term hydrological variation was used to select pools along a gradient of habitat stability. Initial conductivity was a good indicator for the length of inundations. No hatching occurred under elevated conductivities, which may present a mechanism to avoid abortive hatching. Egg bank size was unaffected by habitat size or habitat stability but instead was related to cover by a protective sheet of dry aquatic vegetation, which presumably counteracts egg bank erosion by wind when pools are dry. Life history but not hatching phenology reflected some aspects of habitat stability. Fairy shrimp populations in ephemeral pools started reproduction earlier than populations in more stable habitats. Additional common garden or transplant experiments, however, will be required to assess the relative importance of environmental and genetic components in explaining the observed variation and acquire more insight into the trade-offs that lie at the base of the evolution of life history strategies along the pond permanence gradient.     

Metazoan parasites of African annual killifish (Nothobranchiidae): abundance,diversity, and their environmental correlates

Estimates of biodiversity and its global patterns are affected by parasite richness and specificity. Despite this, parasite communities are largely neglected in biodiversity estimates, especially in the tropics. We studied the parasites of annual killifish of the genus Nothobranchius that inhabit annually desiccating pools across the African savannah and survive the dry period as developmentally arrested embryos. Their discontinuous, non‐overlapping generations make them a unique organism in which to study natural parasite fauna. We investigated the relationship between global (climate and altitude) and local (pool size, vegetation, host density and diversity, and diversity of potential intermediate hosts) environmental factors and the community structure of killifish parasites. We examined metazoan parasites from 21 populations of four host species (Nothobranchius orthonotus, N. furzeri, N. kadleci, and N. pienaari) across a gradient of aridity in Mozambique. Seventeen parasite taxa were recorded, with trematode larval stages (metacercariae) being the most abundant taxa. The parasites recorded were both allogenic (life cycle includes non‐aquatic host; predominantly trematodes) and autogenic (cycling only in aquatic hosts; nematodes). The parasite abundance was highest in climatic regions with intermediate aridity, while parasite diversity was associated with local environmental characteristics and positively correlated with fish species diversity and the amount of aquatic vegetation. Our results suggest that parasite communities of sympatric Nothobranchius species are similar and dominated by the larval stages of generalist parasites. Therefore, Nothobranchius serve as important intermediate or paratenic hosts of parasites, with piscivorous birds and predatory fish being their most likely definitive hosts.     

Playing smart vs. playing safe: the joint expression of phenotypic plasticity and potential bet hedging across and within thermal environments

Adaptive phenotypic plasticity evolves when cues reliably predict fitness consequences of life‐history decisions, whereas bet hedging evolves when environments are unpredictable. These modes of response should be jointly expressed, because environmental variance is composed of both predictable and unpredictable components. However, little attention has been paid to the joint expression of plasticity and bet hedging. Here, I examine the simultaneous expression of plasticity in germination rate and two potential bet‐hedging traits – germination fraction and within‐season diversification in timing of germination – in seeds from multiple seed families of five geographically distant populations of Lobelia inflata (L.) subjected to a thermal gradient. Populations differ in germination plasticity to temperature, in total germination fraction and in the expression of potential diversification in the timing of germination. The observation of a negative partial correlation between the expression of plasticity and germination variance (potential diversification), and a positive correlation between plasticity and germination fraction is suggestive of a trade‐off between modes of response to environmental variance. If the observed correlations are indicative of those between adaptive plasticity and bet hedging, we expect an optimal balance to exist and differ among populations. I discuss the challenges involved in testing whether the balance between plasticity and bet hedging depends on the relative predictability of environmental variance.     

Comparative morphology,phylogeny, and classification of West African callopanchacine killifishes (Teleostei: Cyprinodontiformes: Nothobranchiidae)

A phylogenetic analysis combining 63 morphological characters and DNA sequences (3296 bp), comprising segments of the mitochondrial genes 16S and ND2, and the nuclear gene 28S, for 19 taxa of the West African killifish tribe Callopanchacini and 11 out‐group taxa, highly supported the monophyly of the tribe, and made it possible to provide the first unambiguous diagnoses for the included genera (Archiaphyosemion, Callopanchax, Nimbapanchax, and Scriptaphyosemion). The monophyly of the Callopanchacini is supported by six morphological synapomorphies: posterior portion of the mandibular channel consisting of a single open groove; basihyal pentagonal, as a result of a nearly rectangular basihyal cartilage and a triangular bony support; dorsal process of the urohyal usually absent, sometimes rudimentary; presence of a wide bony flap adjacent to the proximal portion of the fourth ceratobranchial; a broad bony flap adjacent to the proximal portion of the fifth ceratobranchial; and haemal prezygapophysis of the pre‐ural vertebra 2 ventrally directed. The analysis indicates that the medially continuous rostral neuromast channel, commonly used to diagnose the tribe, is plesiomorphic. This study also indicates that, among African aplocheiloids, the annual life cycle style developed once in Callopanchax, and then again independently in the clade containing Fundulopanchax and Nothobranchius. © 2015 The Linnean Society of London     

Climate and geographic trends in hatch delay of the treehole mosquito,Aedes triseriatus Say (Diptera: Culicidae)

Eggs of Aedes triseriatus mosquitoes are stimulated to hatch when inundated with water, but only a small fraction of eggs from the same batch will hatch for any given stimulus. Similar hatching or germination patterns are observed in desert plants, copepods, rotifers, insects, and many other species. Bet hedging theory suggests that parents stagger offspring emergence into vulnerable life history stages in order to avoid catastrophic reproductive failures. For Ae. triseriatus, a treehole breeding mosquito, immediate hatching of an entire clutch leaves all of the parent's progeny vulnerable to extinction in the event of a severe drought. Natural selection has likely favored parents that pursued a bet hedging strategy where the risk of reproductive failure is distributed over time. Considering treehole mosquitoes, bet hedging theory could be used to predict that hatch delay would be positively correlated with the likelihood of drought. To test this prediction, we collected Ae. triseriatus from habitats that varied widely in mean annual precipitation and exposed them to several hatch stimuli in the laboratory. Here we report that, as predicted, Ae. triseriatus eggs from high precipitation regions showed less hatch delay than areas of low precipitation. This strategy probably allows Ae. triseriatus to cope with the wide variety of climatic conditions that it faces in its extensive geographical range.     

Obligate annual and successive facultative diapause establish a bet‐hedging strategy of Rhagoletis cerasi (Diptera: Tephritidae) in seasonally unpredictable environments

To cope with temporal and spatial heterogeneity of habitats, herbivorous insects in the temperate zone usually enter diapause that facilitates synchronization of their life cycle with specific stages of host plants, such as fruit ripening. In the present study, we address those factors regulating dormancy responses as part of a ‘longer strategy’ to persist and thrive in temperate environments, focusing on Rhagoletis cerasi, a univoltine, oligophagous species, which overwinters as pupae and emerges when host fruits are available for oviposition at local scale. To ensure population survival and reproduction at habitats with ecological heterogeneity, R. cerasi has evolved a sophisticated diapause strategy based on a combination of local adaptation and diversified bet‐hedging strategies. Diapause duration is determined both by (i) the adaptive response to local host fruit phenology patterns (annual diapause) and (ii) the plastic responses to unpredictable inter‐annual (temporal) climatic variability that drives a proportion of the populations to extend dormancy by entering a second, successive, facultative cycle of prolonged diapause as part of a bet‐hedging strategy. Besides the dormant periods, post‐diapause development (which varies among populations) exerts ‘fine tune’ adjustments that assure synchronization and may correct possible errors. Adults emerging from pupae with prolonged diapause are larger in body size compared with counterparts emerging during the first year of diapause. However, female fecundity rates are reduced, followed by an extended post‐oviposition period, whereas adult longevity remains unaffected. Overall, it appears that R. cerasi populations are adapted to ecological conditions of local habitats and respond plastically to unpredictable environmental (climatic) conditions.     

Bet hedging in desert winter annual plants: optimal germination strategies in a variable environment

In bet hedging, organisms sacrifice short‐term success to reduce the long‐term variance in success. Delayed germination is the classic example of bet hedging, in which a fraction of seeds remain dormant as a hedge against the risk of complete reproductive failure. Here, we investigate the adaptive nature of delayed germination as a bet hedging strategy using long‐term demographic data on Sonoran Desert winter annual plants. Using stochastic population models, we estimate fitness as a function of delayed germination and identify evolutionarily stable strategies for 12 abundant species in the community. Results indicate that delayed germination meets the criteria as a bet hedging strategy for all species. Density‐dependent models, but not density‐independent ones, predicted optimal germination strategies that correspond remarkably well with observed patterns. By incorporating naturally occurring variation in seed and seedling dynamics, our results present a rigorous test of bet hedging theory within the relevant environmental context.     

Eggs of the Australian saltmarsh mosquito,Aedes camptorhynchus,survive for long periods and hatch in instalments: implications for biosecurity in New Zealand

The Australian saltmarsh mosquito, Aedes camptorhynchus (Diptera: Culicidae), is a significant biting pest and disease vector and is the subject of an eradication programme in New Zealand (NZ), where it has been resident for more than 10 years. To better understand the ecology of this common and widespread pest, we studied egg longevity and hatching patterns in the laboratory. By regularly testing for the presence of viable embryos, we found that eggs may last more than 15 months when stored dry (13% viable at this time). Eggs display instalment hatching, with no more than 56% of a batch hatching upon first inundation. Further hatching may occur for at least six inundations and some unhatched eggs may remain viable even after this. Variation in hatching rates can be observed using different water types, with weaker hatching media stimulating lower hatching rates spread over more inundations. By applying average hatching rates to a non‐linear model of natural egg attrition, we showed that egg batches exposed to three inundations should be exhausted (zero live eggs present) in approximately 11 months at the conditions tested here. These findings have implications for the current eradication programme for Ae. camptorhynchus in NZ and for our understanding of the ecology of a widespread and common disease vector in Australia.