To clarify the life history of Clintonia udensis , we investigated its reproductive systems and spatio‐temporal population structure. Pollination experiments and the observation of floral visitors revealed that C. udensis was compatible with both self‐ and outcross‐pollen, and it potentially produces seeds by insect‐mediated outcrossing in natural conditions. In addition, propagation by clonal reproduction from rhizomes was evident. In this study, it was clarified that C. udensis potentially propagates by sexual and asexual reproduction and maintains its population through a stable frequency of flowering. The differences in the dependence on each reproduction mode could be one of the contributing factors for creating a variety of population sizes and distribution patterns of ramets in populations. To clarify the life‐history of Clintonia udensis , we investigated its reproductive systems and spatio‐temporal population structure. In this study, it was clarified that C. udensis potentially propagates by sexual and asexual reproduction and maintains its population through a stable frequency of flowering. The differences in the dependence on each reproduction mode could be one of the contributing factors for creating a variety of population sizes and distribution patterns of ramets in populations.
Spotted wing drosophila, Drosophila suzukii, is a devastating invasive pest of small and stone fruits in the Americas and Europe. To better understand the population dynamics of D. suzukii, we reviewed recent work on juvenile development, adult reproduction, and seasonal variation in life history parameters including the abiotic/biotic factors that influence these processes. Juvenile development is optimal at moderately warm temperatures, and larvae exhibit some immunity to parasitism. Adults use visual cues and substrate-borne vibrations for courtship and exhibit a bimodal locomotor activity pattern (except mated females). Under 20–27 °C and various conditions, development from egg to adult can take 10–17 days, females first lay eggs within 1–8 days and their lifetime fecundity varies from 400. Oviposition is consistently high in raspberry hosts and fruits with lower penetration force, and the presence of Wolbachia endosymbionts can lower fertility. Drosophila suzukii exhibit seasonal variation with a darker winter morph that is more cold tolerant. Also, D. suzukii likely undergo reproductive diapause in the fall, with colder temperatures and shorter day lengths influencing reproduction. To develop viable IPM programs for D. suzukii, knowledge of abiotic and biotic conditions that impact D. suzukii life history parameters and population dynamics is critical, and gaps in the current knowledge are discussed.
Premise of research. Phenotypic traits that consistently mediate species’ responses to environmental variation (functional traits) provide a promising approach toward generalizing ecological and evolutionary patterns and thereby gaining insights into the processes generating them. In the plant functional ecology literature, most trait-based studies have focused on traits mediating either resource competition or responses to variation in the abiotic environment, while traits mediating reproductive interactions have often been neglected. Methodology. Here, I discuss the value of herkogamy, the spatial separation of male and female functions in flowers, as a functional trait in plant reproductive biology and review the evidence relevant to the hypothesis that taxa exhibiting greater herkogamy have historically experienced more reliable pollination and more outcrossed mating systems. Pivotal results. A large body of work in the field of plant reproductive biology has identified a set of nearly ubiquitous correlations between average herkogamy and features of plant mating systems, notably, autofertility (seed set in the absence of pollinators) and outcrossing rate. Herkogamy often varies extensively among populations and species, and the adaptive interpretation is that herkogamy exhibits local adaptation to the reliability of the pollination environment. Conclusions. These results underline the value of herkogamy as a functional trait representing variation in mating histories. Many important insights are likely to emerge from studies leveraging herkogamy as an easily measured proxy of plant mating systems, as already demonstrated in comparative studies and studies of reproductive interactions. Greater consideration of herkogamy and other reproductive-function traits in studies of species coexistence may provide a more complete understanding of community assembly processes.
Studies on reproduction of the dragonfishes, Bathydraconidae, are scarce, and within this family, the reproductive biology of Parachaenichthys charcoti was poorly understood. Herein we present a histologic analysis of P. charcoti ovaries together with data on reproductive effort using fish collected with trammel nets in austral summer at Potter Cove, South Shetland Islands (SSI), and compare this information with that reported for the South Georgia congener Parachaenichthys georgianus. In gravid females of P. charcoti, GSI of 16–31%, mature oocytes of 1.8–3.9 mm and total fecundity (TF) of 9025–18,937 oocytes/individual (X ± SD = 12,617 ± 4019, n = 7) were recorded. The histology of the ovaries confirmed the common characteristics of the Notothenioidei observed macroscopically, i.e., two distinct batches of oocytes, one in the previtellogenic stage (primary growing or cortical alveoli stages) and the other in vitellogenesis and likely to be released in the current season. A longer incubation period of P. charcoti compared with P. georgianus is associated to the colder waters at the SSI. Based on our sampling and reproductive effort data, together with the reported nesting behavior for P. charcoti, it is assumed that this species spawns in nearshore, sheltered waters in summer, presumably from late December to February. Spawning periods of both congeners differ from those reported for other notothenioids in the same Seasonal Pack-ice Zone, suggesting divergence in some aspects of the life strategies in the genus Parachaenichthys. Likewise, although there are no substantial differences between P. charcoti and other notothenioids regarding gonadal development, the genus Parachaenichthys shows distinct features in its reproductive strategies (e.g., higher TF) compared with other bathydraconid species.
Individuals of Aechmea bracteata show inflorescences with red scape bracts and odourless, yellow, tubular diurnal flowers, with closely arranged sexual organs, producing a large amount of fruits. In order to investigate the reproductive system of this species, a suite of characters was assessed: phenology, floral morphology and biology, nectar production dynamics, and fruit and seed production and germination, as a result of controlled pollination crosses. The study was conducted during two flowering seasons in wild populations in Yucatán, Mexico. Results suggest an annual flowering pattern with one flowering peak; flowers were diurnal, showing partial dichogamy (protandry)‐herkogamy, anthers and stigma become mature before floral aperture, which could lead to self‐pollination, nectar is produced during anthesis, varying in volume and total sugar concentration during the day; fruits and seeds were produced in all experimental crosses (cross‐pollination, obligated cross‐pollination, assisted and unassisted selfing, geitonogamy and apomixis), as well as high percentage seed germination. Several species of Aechmea are reportedly self‐compatible and autogamous, as suggested by results of selfing and non‐assisted selfing crosses, but these results are negated by the presence of apomixis, indicating that the species is apomictic. This is the first report of this breeding system for subgenus Aechmea and the sixth for Bromeliaceae. Polyembryony is here suggested for the first time in this genus and family based on the fact that more seeds were recorded that expected based on ovule numbers. Finally, when performing experimental crosses, estimating reproductive success based on number of seeds is a better approach than number of fruits, due to the effect of pseudogamy.
Genlisea violacea is a Brazilian endemic carnivorous plant species distributed in the cerrado biome, mainly in humid environments, on sandy and oligotrophic soil or wet rocks. Studies on reproductive biology or pollination in the Lentibulariaceae are notably scarce; regarding the genus Genlisea , the current study is the first to show systematic and standardised research on reproductive biology from field studies to describe the foraging of visiting insects and determine the effective pollinators of Genlisea . We studied two populations of G. violacea through the observation of flower visitors for 4 months of the rainy and dry seasons. Stigmatic receptivity, pollen viability, and breeding system were evaluated together with histochemistry and morphological analyses of flowers. The flowers showed stigmatic receptivity of 100% in open buds and mature flowers, reducing to 80% for senescent flowers. Nearly 80% of pollen grains are viable, decreasing to 40–45% after 48 h. Nectar is produced by glandular trichomes inside the spur. Two bee species are effective pollinators: one of the genus Lasioglossum (subgenus Dialictus : Halictidae) and the other of the genus Ceratina (subgenus Ceratinula : family Apidae). Moreover, bee‐like flies of the Syrphidae family may also be additional pollinators. Genlisea violacea is an allogamous and self‐compatible species. The differences in flower‐visiting fauna for both populations can be attributed to factors such as climate, anthropogenic effect, seasonal factors related to insects and plants, as well as the morphological variation of flowers in both populations.
Trichloris crinita is a perennial forage grass species native to arid regions of the American continent. Due to its extensive area of distribution, good forage quality and resistance to drought and grazing, this species is widely utilised as forage and for revegetation purposes in environments with low water availability. Despite its importance, genetic improvement of T. crinita has been very limited, partly as consequence of the lack of knowledge on its mode of reproduction. In the present work, we studied the reproductive biology of T. crinita by means of embryological analyses, flow cytometric seed screen (FCSS), self‐compatibility tests and progeny testing with morphological and molecular markers. Cytological analyses revealed embryo sacs with eight nuclei and of Polygonum type for all T. crinita accessions analysed. FCSS histograms exhibited two clear peaks corresponding to 2C and 3C DNA content, indicating embryo sacs of sexual origin. Controlled pollination experiments designed to evaluate seed set (%) demonstrated that T. crinita is self‐compatible, whereas results from morphological and simple sequence repeat (SSR) marker analysis of progeny revealed lack of outcrossing. Together, these results indicate that T. crinita reproduces sexually. It is a self‐compatible and autogamous species. It is expected that these data will have a positive impact in the genetics and breeding of this species, and therefore contribute to its proper utilisation in arid regions.
Ascidians are abundant and well-represented members of worldwide benthic communities, including Antarctica and the Arctic. These organisms exhibit different reproductive patterns usually related to a latitudinal gradient, as do many marine invertebrate species. Reproductive seasonality varies from one or two annual peaks in cold and temperate water species to continuous reproduction throughout the year in warm water species. Styela rustica (Linnaeus 1767) and Halocynthia pyriformis (Rathke 1806) are solitary species with external fertilization and a wide distribution range, from the North Atlantic to the Arctic. The reproductive patterns of these two species were assessed for Arctic populations by year-round sampling and structural analysis of the gonads. Both species are hermaphrodites and showed marked seasonality in oocyte maturity and spawning; S. rustica peaked during the boreal summer and H. pyriformis in late spring. The two species also showed marked differences in mature oocyte sizes: H. pyriformis almost doubled those of S. rustica and, while spermatocytes of H. pyriformis were mature year-round, the maturity of male and female gametes was synchronized in S. rustica. The species thus showed an annual reproductive cycle coupled with a higher production period in the ecosystem, but also exhibited different strategies developed under the same environmental pressures.
It has been hypothesized that the fitness of selfed progeny must be lowered by inbreeding depression. Most research into the breeding systems of orchids shows a similar fruit set from outcrossing and self-pollination, but few studies have measured seed production and viability. In five populations of Laelia autumnalis, in central Mexico, we studied the species reproductive system and the early costs of endogamy. We performed spontaneous self-pollination, apomixis, assisted self-pollination, cross-pollination, and exogamous pollination (using pollen from a different population) treatments of bagged flowers and measured fruit set, seed production, and germination. No fruits were produced in the apomixis and spontaneous self-pollination treatments. Reproductive success from self-pollination was lower than that from cross- and exogamous pollination and no difference was found between the latter two treatments. The ratio between self-pollination and cross-pollination success in different traits ranged from 0.80 +/- 0.18 (fruit set) to 0.22 +/- 0.13 (seeds with embryo). The latter value suggests a high endogamy costs in the production of viable seeds. The concatenated success of the different traits studied showed that the relative fitness of self-pollination was 63% lower than with cross-pollination. Laelia autumnalis is a self-compatible non-autogamous species in which the cost of endogamy occurs at seed production and cannot be compensated for at other early stages. This also occurs in other orchid species and is likely to be a general pattern.
The reproductive system of Orchidaceae is predominantly xenogamous and highly dependent on animal pollen vectors. Nectar is the main floral resource, offered to pollinators in perigonal nectaries, cuniculi or spurs; these structures are often difficult to locate and to evaluate their functionality. The Neotropical Barb. Rodr. and Salzm. ex. Lindl. bloom synchronously throughout the year in the municipality of Maricá (Rio de Janeiro State, SE Brazil). The flowers of open in the morning, have a conspicuous pink colour, a nectar guide, and nuptial and extranuptial nectaries. During the day, they are visited by species of Hesperiidae (Lepidoptera), which remove the pollinia. The flowers of open at night, are green with nuptial and extranuptial nectaries, and have a strong odour at night, suggesting nocturnal pollination agents, possibly moths. To date, no information is available on the reproductive biology and pollination mechanisms for , nor is micromorphological, anatomical or histochemical data related to the presence and functionality of secretory structures associated with pollination in either species. Also, no studies have examined the occurrence of mechanisms that hinder or prevent interspecific pollination. Here, through reproductive, morphological, structural and histochemical analyses, we evaluated the floral biology and reproductive systems of these synchronopatric species. Both species have extranuptial nectaries, a functional cuniculus, and osmophores. Hand-pollination experiments revealed that the species are self- and intercompatible, although individuals with intermediate morphology were not identified. Pre-pollination barriers related to the floral biology of the species seem to be sufficient to prevent hybridization, but other biological aspects certainly contribute to the genetic integrity of the populations, such as the low rates of visits to flowers, low percentage of fruit and seed set, low seedling recruitment, and high investment in vegetative propagation.