Gender-role adaptation depending on trade-offs between growth and reproduction in the simultaneously hermaphroditic freshwater snail,Physa acuta

Floral development depends on multifactor processes related to genetic, physiological, and ecological pathways. Plants respond to herbivores by activating mechanisms aimed at tolerating, compensating, or avoiding loss of biomass and nutrients, and thereby survive in a complex landscape of interactions. Thus, plants need to overcome trade-offs between development, growth, and reproduction vs. the initiation of anti-herbivore defences. This study aims to assess the frequency of phloem-feeding herbivores in wild populations of the Etruscan honeysuckle (Lonicera etrusca Santi) and study their effects on floral development and reproduction. The incidence of herbivory by the honeysuckle aphid (Hyadaphis passerinii del Guercio) was assessed in three wild populations of the Iberian Peninsula. The effect of herbivory on floral morphology, micromorphology of stigmas and pollen, floral rewards, pollination, and fruit and seed set were studied. The herbivory by aphids reduces the size of flowers and pollen. Additionally, it stops nectar synthesis and causes malformation in pollen and microstructures of stigmas, affecting pollination. As a consequence, fruit set and seed weight are reduced. This work provides evidence of the changes induced by phloem-feeding herbivores in floral development and functioning that affect the ecological processes necessary to maintain the reproductive success of plants.

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Sex ratio and life history traits at reaching sexual maturity in the dioecious shrub Fuchsia parviflora: field and common garden experiments

Journal of Tropical Ecology ◽

10.1017/s0266467421000043 ◽

2021 ◽

pp. 1-6

Author(s):

Jessica S. Ambriz ◽

Clementina González ◽

Eduardo Cuevas

Keyword(s):

Natural Population ◽

Sexual Maturity ◽

Sex Ratios ◽

Natural Populations ◽

Common Garden ◽

Common Garden Experiment ◽

Trade Offs ◽

Reproductive Biomass ◽

Common Garden Experiments ◽

Growth And Reproduction

Abstract Fuchsia parviflora is a dioecious shrub that depends on biotic pollination for reproduction. Previous studies suggest that the male plants produce more flowers, and male-biased sex ratios have been found in some natural populations. To assess whether the biased sex ratios found between genders in natural populations are present at the point at which plants reach sexual maturity, and to identify possible trade-offs between growth and reproduction, we performed a common garden experiment. Finally, to complement the information of the common garden experiment, we estimated the reproductive biomass allocation between genders in one natural population. Sex ratios at reaching sexual maturity in F. parviflora did not differ from 0.5, except in one population, which was the smallest seedling population. We found no differences between genders in terms of the probability of germination or flowering. When flowering began, female plants were taller than males and the tallest plants of both genders required more time to reach sexual maturity. Males produced significantly more flowers than females, and the number of flowers increased with plant height in both genders. Finally, in the natural population studied, the investment in reproductive biomass was seven-fold greater in female plants than in male plants. Our results showed no evidence of possible trade-offs between growth and reproduction. Despite the fact that female plants invest more in reproductive biomass, they were taller than the males after flowering, possibly at the expense of herbivory defence.

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Angucycline-like Aromatic Polyketide from a Novel Streptomyces Species Reveals Freshwater Snail Physa acuta as Underexplored Reservoir for Antibiotic-Producing Actinomycetes

Antibiotics ◽

10.3390/antibiotics10010022 ◽

2020 ◽

Vol 10 (1) ◽

pp. 22

Author(s):

Nasim Safaei ◽

Yvonne Mast ◽

Michael Steinert ◽

Katharina Huber ◽

Boyke Bunk ◽

...

Keyword(s):

High Throughput Sequencing ◽

Genome Mining ◽

Freshwater Snail ◽

Whole Genome Sequence ◽

Phylogenomic Analysis ◽

Ionization Mass ◽

Gram Positive ◽

Streptomyces Species ◽

Genus Streptomyces ◽

Physa Acuta

Antibiotic producers have mainly been isolated from soil, which often has led to the rediscovery of known compounds. In this study, we identified the freshwater snail Physa acuta as an unexplored source for new antibiotic producers. The bacterial diversity associated with the snail was characterized by a metagenomic approach using cultivation-independent high-throughput sequencing. Although Actinobacteria represented only 2% of the bacterial community, the focus was laid on the isolation of the genus Streptomyces due to its potential to produce antibiotics. Three Streptomyces strains (7NS1, 7NS2 and 7NS3) were isolated from P. acuta, and the antimicrobial activity of the crude extracts were tested against a selection of Gram-positive and Gram-negative bacteria and fungi. 7NS3 showed the strongest activity against Gram-positive bacteria and, thus, was selected for genome sequencing and a phylogenomic analysis. 7NS3 represents a novel Streptomyces species, which was deposited as Streptomyces sp. DSM 110735 at the Leibniz Institute-German Collection of Microorganisms and Cell Cultures (DSMZ). Bioassay-guided high-performance liquid chromatography (HPLC) and high-resolution electrospray ionization-mass spectrometry (HR-ESI-MS) analyses of crude extract fractions resulted in the detection of four compounds, one of which matched the compound characteristics of emycin A, an angucycline-like aromatic polyketide. Genome mining studies based on the whole-genome sequence of 7NS3 resulted in the identification of a gene cluster potentially coding for emycin A biosynthesis. Our study demonstrates that freshwater snails like P. acuta can represent promising reservoirs for the isolation of new antibiotic-producing actinobacterial species.

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Effect of cadmium on the embryos and juveniles of a tropical freshwater snail, Physa acuta (Draparnaud, 1805)

Water Science & Technology ◽

10.2166/wst.1998.0300 ◽

1998 ◽

Vol 38 (7) ◽

pp. 263-270 ◽

Cited By ~ 14

Author(s):

C. C. C. Cheung ◽

P. K. S. Lam

Keyword(s):

Early Life ◽

Freshwater Snail ◽

Toxicity Tests ◽

Life Stages ◽

Early Life Stages ◽

Physa Acuta ◽

Ecotoxicological Tests ◽

Embryonic Growth ◽

Potential Use ◽

Tropical Freshwater

The effects of cadmium on early life stages of a freshwater snail, Physa acuta (Draparnaud), were investigated. The 24- and 48-hour LC50 for embryos were 1.27 mg/l (95% confidence interval: 1.13 - 1.42) and 0.85 mg/l (0.71 - 1.01), respectively. The 24- and 48-hour LC50 for juveniles were 1.32 mg/l (1.13 - 1.54) and 1.05 mg/l (0.81 - 1.36), respectively. An increase in cadmium concentrations at sublethal levels resulted in a significant reduction in embryo growth rate and embryo hatchability. Developmental deformities of the embryos were also observed. The NOEC and LOEC for embryonic growth were 0.32 and 0.50 mg/l, respectively, and the LOEC for hatchability was 0.13 mg/l. These results suggest that embryonic growth and hatchability are useful endpoints in chronic toxicity tests. In addition, the potential use of early life stages of pulmonate snails in ecotoxicological tests is discussed.

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