Reproductive ecology and genetic variability in natural populations of the wild potato,Solanum kurtzianum

The cultivated potato (Solanum tuberosum ssp. tuberosum) has more than 200 related wild species distributed along the Andes, adapted to a wide range of geographical and ecological areas. Since the last century, several collection expeditions were carried out to incorporate genetic variability into the potato germplasm around the world. However, little is known about the reproductive ecology and genetic population structure of natural potato population from field studies. The aim of this work is to study, in the field, the genetic variability and reproductive strategies of populations of one of the most widely distributed potato species in Argentina, Solanum kurtzianum, growing in Mendoza province. AFLP markers showed that the genetic variability is mainly present among plants within populations, indicating that in the sampled populations, sexual reproduction is more relevant than clonal multiplication (by tubers). Additional evidence was obtained evaluating the genetic diversity in populations with a distribution in patches, where several genotypes were always detected. From a field study performed in the Villavicencio Natural Reserve, we found that the average number of plump seeds per fruit was 94.3, identified and calculated the foraging distance of four insect pollinators, and demonstrated the seed dispersal by storm water channels. We argue that the breeding system, the two modes of reproduction and the ecological interaction described here may have a prominent role in determining the genetic structure of S. kurtzianum populations, and discuss the importance of field studies on population genetics, reproductive biology and ecology to design collections and conservation strategies.     

Embryo ecology: Developmental synchrony and asynchrony in the embryonic development of wild annual fish populations

Embryo–environment interactions are of paramount importance during the development of all organisms, and impacts during this period can echo far into later stages of ontogeny. African annual fish of the genus Nothobranchius live in temporary pools and their eggs survive the dry season in the dry bottom substrate of the pools by entering a facultative developmental arrest termed diapause. Uniquely among animals, the embryos (encased in eggs) may enter diapause at three different developmental stages. Such a system allows for the potential to employ different regulation mechanisms for each diapause. We sampled multiple Nothobranchius embryo banks across the progressing season, species, and populations. We present important baseline field data and examine the role of environmental regulation in the embryonic development of this unique system. We describe the course of embryo development in the wild and find it to be very different from the typical development under laboratory conditions. Development across the embryo banks was synchronized within and across the sampled populations with all embryos entering diapause I during the rainy season and diapause II during the dry season. Asynchrony occurred at transient phases of the habitat, during the process of habitat desiccation, and at the end of the dry season. Our findings reveal the significance of environmental conditions in the serial character of the annual fish diapauses.     

Reproductive ecology of the river lamprey

The reproductive ecology of river lamprey Lampetra fluviatilis was investigated during the spawning period 2003 in the River Derwent, north‐east England. Over this period 1199 ± 104 individuals day⁻¹(mean ±  s . d .) were counted on one spawning site (area c . 450 m²), but mark‐recapture estimates suggested that >5000 river lamprey used this site over the same period and egg deposition was estimated as 168 000 eggs m⁻². The operational sex ratio of river lamprey in spawning clusters changed between spawning phases, from domination by females during the nest‐building phase (male : female ratio, 1 : 3·46), to a preponderance of males during the spawning phase (male : female, 1 : 0·37), followed by a return to a majority of females after spawning (male : female, 1 : 3·74). Recapture data showed that >97% of recaptured, tagged males were recorded at two or more nests, whereas almost 50% of recaptured, tagged females were recorded at the same nest, suggesting a promiscuous mating system, with a tendency towards polygyny within the population. Within the lower 80 km of the River Derwent and its tributaries, evidence of river lamprey spawning was found at only six sites, and most spawning (>80% of the observed spawning population) was at one site.     

Predicting infestation parameters and impacts of caligid copepods in wild and cultured fish populations

Summary

The intensity and timing of infestation events of caligid copepods in wild or cultured fish populations may be predicted from previous local production of nauplius I of the parasite. However, this relationship is not well established, the spatial scales over which it operates are unclear, and the role of host reactions to the invading copepodid is unknown. Rate of development (and population structure), generation time and rate and actual reproductive output are temperature-dependent. In Ireland between five and seven generations of Lepeophtheirus salmonis (Krøyer) can develop annually and generation time varies from over 120 days in winter to 23 days in summer. Host reactions may affect the rate of development of the parasite but are less important than temperature. Host reactions may also cause parasite mortality, but this effect is specific for individual host parasite associations. The distribution of L. salmonis in cultured host populations is typically normal but is very over-dispersed in wild populations with heavy infestations. Parasiteinduced morphological damage to the host is correlated with physiological impacts. Physiological effects are present even when morphological damage is slight and so intermittent chemotherapeutic control of infestations cannot prevent some parasite impact from occurring.     

Reproductive ecology of predaceous Heteroptera

Reproductive ecology entails relating the physiology and behavior of an organism to its environment and the community in which it lives. Terrestrial predatory Heteroptera (including Anthocoridae, Geocoridae, Miridae, Nabidae, Pentatomidae, Phymatidae, and Reduviidae) display a wide range of reproductive ecologies. But in spite of this variability, a review of the literature reveals certain underlying trends that are useful in understanding how generalist predators function within their environments. First, the reproductive ecology of predatory bugs is inherently coupled to the physiology of the female and her eggs. Second, three population parameters are directly tied to reproduction (maturation rates, realized fecundity, and reproductive diapause) have great bearing on the rate of population increase and reproductive success of a predatory bug, but these three parameters fluctuate widely within and among species. The variables that affect these processes include the physiological status of the mother (mating status, age and size, and nutritional status), the abiotic environment in which she and her eggs live (temperature, photoperiod, water availability), and natural enemies that attack eggs and reproductive females. A final trend observed in the literature involves the hierarchy of events that must occur before a female finds a suitable oviposition site. Females all must locate preferred habitats, plants/substrates, and microsites in which to insert or deposit an egg, but they use a variety of tactics and cues in order to accomplish this, depending on their life history traits. Examining the factors that constrain and promote the reproductive potential of predatory Heteroptera will make biological control programs that center on them more reliable and sustainable.     

Reproductive ecology of a neotropical cichlid fish,Cichla monoculus (Osteichthyes: Cichlidae)

The reproductive ecology of the freshwater fish Cichla monoculus Spix, 1831 (Osteichthyes: Cichlidae) was investigated in the Campo Grande Reservoir, Northeast Brazil. Rainfall, temperature, pH, dissolved oxygen and electrical conductivity of the water were recorded monthly. Fish collected on a monthly basis were measured, weighted, dissected, sexed and the stage of maturation of the gonads were assessed by macro and microscopic means. The semi-arid study region has short spells of rain of 2-3 months duration interspersed with dry seasons. A positive correlation was observed between rainfall and air and water temperatures and conductivity of the water. The study population had an extended spawning season, with peak reproductive activity coinciding with low water temperatures. Males were longer and heavier than females on average and were larger at onset of sexual maturity. The size frequency distributions of the oocytes indicate that C. monoculus is a multiple spawner with an estimated batch fecundity of 3100. Condition factor showed an inverse relationship in relation to gonad size during maturation in both sexes and spent fish were in poor condition. In mature males, lipid stores in the post-occipital cephalic protuberance, a secondary sexual characteristic developed during the reproductive phase, which depleted in spent individuals. The success of this fish is attributed to its reproductive capacity and to the phenotypic plasticity that allows it to adapt to the harsh ecological conditions that prevail in the semi-arid region of Northeast Brazil.     

Reproductive ecology of the Springhaas Pedetes capensis in Botswana

The reproductive ecology of the Springhaas was studied in the Republic of Botswana (August 1971-August 1974). Springhaas were collected over 24 consecutive months (153 foetuses and 560 juveniles and adults). Springhaas are monotocous. There was no difference between the number of implantations in each uterine horn. Seventy-six per cent of adult females were pregnant, 46 % were lactating, and only 4 % were neither pregnant nor lactating. Neonates are confined to the burrow and totally dependent upon the mother until they attain a body weight of approximately 1.3 kg. The male to female ratio was 51:49, and the juvenile to adult ratio was 28:72. No seasonal peaks in reproductive effort were noted. The reproductive strategy of the Springhaas is considered. Predation is believed to be the primary mover in the evolution of the Springhaas reproductive strategy.     

Reproductive senescence: new perspectives in the wild

According to recent empirical studies, reproductive senescence, the decline in reproductive success with increasing age, seems to be nearly ubiquitous in the wild. However, a clear understanding of the evolutionary causes and consequences of reproductive senescence is still lacking and requires new and integrative approaches. After identifying the sequential and complex nature of female reproductive senescence, we show that the relative contributions of physiological decline and alterations in the efficiency of parental care to reproductive senescence remain unknown and need to be assessed in the light of current evolutionary theories of ageing. We demonstrate that, although reproductive senescence is generally studied only from the female viewpoint, age‐specific female reproductive success strongly depends on male–female interactions. Thus, a reduction in male fertilization efficiency with increasing age has detrimental consequences for female fitness. Lastly, we call for investigations of the role of environmental conditions on reproductive senescence, which could provide salient insights into the underlying sex‐specific mechanisms of reproductive success. We suggest that embracing such directions should allow building new bridges between reproductive senescence and the study of sperm competition, parental care, mate choice and environmental conditions.     

Reproductive ecology of Caribbean reef corals

The last decade has seen a resurgence of interest in the processes of sexual reproduction by scleractinian reef corals. Earlier investigations had focused fortuitously on brooding (planulating) species, which resulted in the general misconception that brooding was the main form of larval development of reef corals. More recent work on Indo-Pacific species has shown broadcast spawning and short annual reproductive periods to predominate. This report presents the reproductive patterns of eleven Caribbean coral species and attempts to explain the adaptive features and selective pressures that have led to the evolution of the four reproductive patterns described to date: (a) hermaphroditic broadcasters; (b) gonochoric broadcasters; (c) hermaphroditic broadcasters; (b) gonochoric brooders. Both (a) and (b) correlate with large colony size and short annual spawning periods; and (c) and (d) correlate with small colony size, multiple planulating cycles per year, and occupation of unstable habitats. Selection for outcrossing between long-lived individuals is proposed as the reason for gonochorism and for synchronous spawning of hermaphroditic broadcasters, and also for the large amount of sperm produced by hermaphroditic brooders. Selection for high rates of local recruitment is proposed as the force behind the evolution of brooding by species inhabiting unstable habitats and suffering high rates of adult mortality.     

Reproductive ecology of the lacertid lizard Podarcis bocagei

This paper presents data on aspects of the reproductive ecology of a population of Podarcis bocagei in northwestern Spain, as monitored over a two-year period (1990–1991) Data were obtained principally on the basis of mark-recapture experiments, but also from laboratory hatching studies Mating took place between the end of March and July During the laying period, from May to July, 8 5% of reproductive females produced three clutches, 52 1% two clutches, and 39 4% one clutch In general, single clutches were produced by small females Only a small proportion of large females produced three clutches Mean clutch size was 4 8 eggs (range 4–7) in May, 4 3 (2–6) in June and 3 9 (2–4) in July There was sigmficant variation in the mean snout-to-vent length (SVL) of females laying in each month of the season Both clutch size and mean single-egg volume increased with mother's SVL There was a significant partial correlation between egg volume and clutch size when both mother's SVL and month of laying were held constant There was no significant between-year variation in clutch size, breeding females' SVL, egg weight or relative clutch mass A delay in the timing of reproductive events in one year (1991) is attributable to adverse weather conditions during early spring Hatching occurred between July and September Hatch success (as estimated in 1989, 1990 and 1991 from natural nests at the study site) was high, ranging from 83% in 1991 to 91% in 1989 The mean SVL of female hatchlings was greater than that of male hatchlings By contrast, adult females had lower mean SVL than adult males     

Domestication, comparative biology and interactions of wild and cultured fish: convenor's synthesis

Aquaculture is expanding rapidly and many fish species are brought into cultivation, entering a process of domestication with consequences for their morphology, physiology, ecology and evolution. In some species the abundance of cultured populations matches or exceeds that of wild stocks, and interactions between cultured and wild fish can pose significant conservation challenges. At the same time, captive breeding and re‐introduction play an important role in the conservation of some of the world's most endangered fishes. Drawing on contributions from the FSBI Symposium and the wider literature, we synthesize current knowledge of the process and extend of fish domestication, interactions between cultured and wild fish, and the use of cultured fish in fisheries enhancement and restoration. We provide a perspective on the role of biological issues within the wider context of aquaculture development and aquatic conservation biology, and conclude with a discussion of promising avenues for further research.     

Reproductive ecology of Brazilian freshwater fishes

We used metadata on nine reproductive traits of 67 species of Brazilian iteroparous, oviparous, teleost freshwater fishes to test phenotypes associations to discriminate species that only spawn in large rivers (lotic fishes) from those capable to spawn in lentic habitats (lentic fishes). We tested the hypothesis that lotic fishes present spawning migration, shorter spawning season, single spawning, no parental care, free eggs, higher relative fecundity, faster embryogenesis, and larger size, while lentic fishes present no spawning migration, longer spawning season, multiple spawning, parental care, adhesive eggs, lower relative fecundity, slower embryogenesis, and smaller size. Our analyses supported the hypothesis but not all phenotypic associations satisfied it, specifically with regard to lentic fishes or to pairs of phenotypes typical of lentic fishes. We also concluded that spawning in large rivers is a better predictor of bionomic characters than spawning in lentic habitats, and lotic fishes are specialists compared to lentic fishes.     

Reproductive ecology of the glacier lanternfish Benthosema glaciale

Myctophids play a key role in the transfer of energy in pelagic food webs, linking zooplankton to higher trophic levels. Data are presented, for the first time for the glacier lanternfish (Benthosema glaciale), on maturity ogives, size-at-maturity and reproductive strategy in terms of ovarian organization and fecundity type in two contrasting environments: North Atlantic and Mediterranean. We analysed 292 females collected in Flemish Cap during early summer 2009 and 2011 and off the Balearic Islands during late autumn 2009 and early summer 2010. The spawning season differed between areas. Size at 50% maturity in Flemish Cap was 47.6 and 49.1 mm in 2009 and 2011, respectively, but significantly smaller, 24.5 mm, in the Balearic sea. B. glaciale is a batch spawner with asynchronous ovarian development and indeterminate fecundity. Batch fecundity showed significant relationships with length and weight, although average relative batch fecundity was low (1031 ± 396 oocytes/gram). We compared two staining techniques: Hematoxylin–eosin and PAS–hematoxylin–metanil yellow with the latter being more useful to detect mature females and spawning indicators in regressing and regenerating females. Our results contribute to a better understanding of the reproductive potential and ecological role of this species, the most abundant myctophid in the northern Atlantic.     

Reproductive ecology of the boreal riparian guild of Drosophila

The reproductive ecology of four sympatric Drosophila virths group species (Diptera Drosophilidae) was studied in the field to trace the factors maintaining species isolation There was a high probability of meeting a heterospecific individual belonging to the same species group on the basis of adult spatial occurrence Direct field observations revealed that the males court also females of the foreign species but interspecific courtships do not lead to mating The main mating period among these species lasted only several weeks and the timing of mating periods differed markedlv in the three most common species Reproductive character displacement between species may explain the observed differences in the timing of the mating periods but they could have arisen in the context of other selective pressures than the prevention of interspecific courtships and matings     

Reproductive ecology and the persistence of an endangered plant

Amsinckia grandiflora (large-flowered fiddleneck)is an extremely rare California annual wildflower, known only from threepopulations. We conducted field and greenhouse experiments to compare the rareheterostyle with a cryptic self-incompatibility system (A.grandiflora) to a common, self-compatible, homostylous, sympatriccongener (A. tessellata). Inter-species comparisons ofadult plants suggested that in the greenhouse, A.grandiflora balances low floral seed set (seeds per flower) withincreased floral output (flowers/plant) and a greater number of flowers perinflorescence. Seed set from active self-, intra- and inter-morph pollinationswas high in A. grandiflora, indicating that the crypticself-incompatibility system does not prevent seed set in the species. In thefield, A. grandiflora floral output was only slightlygreater than for A. tessellata, and did not fully balance lowerfloral seed set. Amsinckia tessellata average seed weightwas lower than that of A. grandiflora, which, along with the lowernumber of flowers produced, indicated lower maternal investment per nutlet thanfor A. grandiflora. Under conditions of unlimited resources, itappears that A. grandiflora fitness is not intrinsicallylimited when compared to its weedy relative A. tessellata.The differences in nutlet output between A. grandiflora andA. tessellata under field conditions are more likely due todifferential responses to extrinsic factors such as competition and pollinatoravailability.     

Reproductive ecology of the marine pulmonate,onchidium verruculatum

O. verruculatum shows aggregated spatial dispersion during the pre-reproductive and reproductive period, which appears to be closely related with propagative requirements. Analysis of the stomach contents and laboratory observations indicate that O. verruculatum feeds on marine sea weeds (Padina and Ulva).     

Reproductive ecology of four subtidal red algae

The reproduction and stature of the red algae Callophyllis cristata (C. Ag.) Kuetz., Membranoptera alata (Huds.) Stackh., Phycodrys rubens (Huds.) Batt., and Ptilota serrata Kuetz. were recorded from subtidal populations at Appledore Island, Maine, U.S.A., with respect to time and depth. Only Membranoptera alata exhibited a conspicuous seasonal fluctuation of reproduction. A vertical gradient of reproduction was evident, with reduced levels of reproduction in shallow populations of Phycodrys rubens and Ptilota serrata, as well as deep populations of Phycodrys rubens, Membranoptera alata and Callophyllis cristata. Differential stratification of the reproductive phases of Ptilota serrata occurred with higher frequencies of tetrasporic plants in deep populations and of cystocarpic plants in shallow populations. In contrast, the haploid and diploid plants of the other three species showed similar distributional patterns. Membranoptera alata, Phycodrys rubens, and Callophyllis cristata showed a conspicuous decrease in stature during maximum reproduction.     

Reproductive performance of wild boar females in Portugal

Reproductive tracts of 214 female wild boars collected in Central Portugal between October and February over the period 1997 to 2001 were examined. From this material, we were able to determine reproductive phenology (conception and birth periods) as well as age and weight of sows at puberty, ovulation rates of adults, foetal sex ratio, levels of intrauterine mortality, final litter size and postnatal mortality. Differences between year, region, age and body weight were analysed. A total of 66.8% of the females examined were gestating or lactating and 96.3% of these weighed >40 kg. The highest proportions of pregnant sows were found in the adult age/weight classes (74%). None of the juvenile females (1 year old and younger) were lactating and only 7% was pregnant. The average number of foetuses/female (4.1 ± 1.2SD) and that of corpora lutea per female (4.6 ± 1.7SD) increased from lighter and younger to heavier and older wild sows. Foetal sex ratio was biased towards males (1.3:1). Observed intrauterine mortality rate (9.7%) and postnatal mortality (6.3%) were among the lowest recorded in European wild boar populations. The productivity rate of the Central Portuguese wild boar population was calculated as 1.1 young per individual in the population. Conception and birth periods did not differ significantly between the considered 4 years. Birth synchronisation was pronounced in all the years, with a peak of births occurring in March.