Hubbry Logo
AndrodioecyAndrodioecyMain
Open search
Androdioecy
Community hub
Androdioecy
logo
7 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Androdioecy
Androdioecy
Androdioecy
View on Wikipedia
from Wikipedia

Androdioecy /ˌændroʊdaɪˈiːsi/ is a reproductive system characterized by the coexistence of males and hermaphrodites. Androdioecy is rare in comparison with the other major reproductive systems: dioecy, gynodioecy and hermaphroditism.[1] In animals, androdioecy has been considered a stepping stone in the transition from dioecy to hermaphroditism, and vice versa.[2]

Androdioecy, trioecy and gynodioecy are sometimes referred to as a mixed mating systems.[3] Androdioecy is a dimorphic sexual system in plants comparable with gynodioecy and dioecy.[4]

Evolution of androdioecy

[edit]

The fitness requirements for androdioecy to arise and sustain itself are theoretically so improbable that it was long considered that such systems do not exist.[5][6] Particularly, males and hermaphrodites have to have the same fitness, in other words produce the same number of offspring, in order to be maintained. However, males only have offspring by fertilizing eggs or ovules of hermaphrodites, while hermaphrodites have offspring both through fertilizing eggs or ovules of other hermaphrodites and their own ovules. This means that all else being equal, males have to fertilize twice as many eggs or ovules as hermaphrodites to make up for the lack of female reproduction.[7][8]

Androdioecy can evolve either from hermaphroditic ancestors through the invasion of males or from dioecious ancestors through the invasion of hermaphrodites. The ancestral state is important because conditions under which androdioecy can evolve differ significantly.[citation needed]

Androdioecy with dioecious ancestry

[edit]

In roundworms, clam shrimp, tadpole shrimp and cancrid shrimps, androdioecy has evolved from dioecy. In these systems, hermaphrodites can only fertilize their own eggs (self-fertilize) and do not mate with other hermaphrodites. Males are the only means of outcrossing. Hermaphrodites may be beneficial in colonizing new habitats, because a single hermaphrodite can generate many other individuals.[9]

In the well-studied roundworm Caenorhabditis elegans, males are very rare and only occur in populations that are in bad condition or stressed.[10] In Caenorhabditis elegans androdioecy is thought to have evolved from dioecy, through a trioecous intermediate.[11]

Androdioecy with hermaphroditic ancestry

[edit]

In barnacles, androdioecy evolved from hermaphroditism.[3] Many plants self-fertilize, and males may be sustained in a population when inbreeding depression is severe because males guarantee outcrossing.[citation needed]

Types of androdioecy

[edit]

The most common form of androdioecy in animals involves hermaphrodites that can reproduce by autogamy or allogamy through ovum with males. However, this type does not involve outcrossing with sperm. This type of androdioecy generally occurs in predominantly gonochoric taxonomy groups.[12]: 21 

One type of androdioecy contains outcrossing hermaphrodites which is present in some angiosperms.[12]: 21 

Another type of androdioecy has males and simultaneous hermaphrodites in a population due to developmental or conditional sex allocation. Like in some fish species small individuals are hermaphrodites and under circumstances of high density, large individuals become male.[12]: 21 

Androdioecious species

[edit]

Despite their unlikely evolution, 115 androdioecious animal and about 50 androdioecious plant species are known.[2][13] These species include

Anthozoa (Corals)

[edit]

Nematoda (Roundworms)

[edit]

Rhabditidae (Order Rhabditida)

Diplogastridae (Order Rhabditida)

Steinernematidae (Order Rhabditida)

Allanotnematidae (Order Rhabditida)

Dorylaimida

Nemertea (Ribbon worms)

[edit]

Arthropoda

[edit]

Clam shrimp

Tadpole shrimp

Barnacles

Lysmata

Insects

Annelida (Ringed worms)

[edit]

Chordata

[edit]

Angiosperms (Flowering plants)

[edit]

See also

[edit]

References

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Androdioecy

View on Grokipedia
from Grokipedia
Androdioecy is a rare in characterized by the coexistence of hermaphroditic individuals, which produce both and ovules, and purely male individuals, which produce only , within the same population, with no purely female individuals present. This reproductive strategy contrasts with more common systems like hermaphroditism or and is documented in only a handful of , often involving functional aspects where hermaphroditic flowers may have reduced or sterile male function. The evolutionary maintenance of androdioecy poses significant theoretical challenges, as models predict that males can only invade and persist in hermaphroditic populations if they possess a substantial advantage in siring success—typically requiring male fertility to be at least twice that of hermaphrodites to offset the latter's capacity for self-fertilization. Despite this instability, androdioecy has arisen independently in various lineages, potentially facilitated by factors such as , , or dynamics that reduce local . In some instances, it represents a transitional state from hermaphroditism toward , though evidence from species like Datisca glomerata suggests origins from a dioecious via the loss of female function in one sex. Notable examples of androdioecy occur in plants such as Datisca glomerata (Datiscaceae), where males and hermaphrodites coexist with confirmed male siring success, Mercurialis annua (Euphorbiaceae), which exhibits environmental influences on sex expression, and Tapiscia sinensis (Tapisciaceae), a tree species with genomic adaptations supporting the system. These cases highlight gender-specific differences in resource allocation, such as higher nutrient investment in vegetative growth by males compared to hermaphrodites, which may contribute to the system's persistence. While primarily studied in angiosperms, similar systems appear in some animals like nematodes, underscoring broader evolutionary patterns in sexual dimorphism.

Overview

Definition

Androdioecy is a sexual system in which populations consist of male individuals that produce only male gametes and hermaphroditic individuals that produce both male and female gametes, with the absence of pure female individuals. The term is pronounced /ˌændroʊˌdaɪˈiːsi/ and derives from the Greek prefix "andro-" meaning male, combined with elements from "dioecy," ultimately referencing the coexistence of males and hermaphrodites as distinct functional "households" within the population. This system occurs rarely in both plants and animals. In androdioecious populations, males contribute solely to male gamete production, such as in plants or in animals, relying on hermaphrodites for female gametes to achieve fertilization. Hermaphrodites, in contrast, can engage in self-fertilization or cross-fertilization, supplying both female gametes (e.g., ovules or eggs) and male gametes to facilitate . This arrangement contrasts with hermaphroditism by introducing separate individuals, promoting while maintaining dual-gamete production in hermaphrodites. Androdioecy is explicitly distinguished from subdioecy, which involves the presence of males, females, and hermaphrodites simultaneously, and from partial , which may include variable proportions of unisexual and bisexual individuals across a spectrum toward full sex separation.

Rarity and Distribution

Androdioecy is an exceedingly rare , documented in a small number of (approximately 50 reported, though only a handful well-confirmed) and 115 worldwide (as of 2024). In contrast, —the coexistence of separate males and females—occurs in roughly 15,600 angiosperm , representing about 6% of all flowering , while hermaphroditism predominates in the vast majority of and taxa. This scarcity underscores androdioecy's limited evolutionary success compared to these more common systems. Recent studies have identified additional cases in nematodes, such as eight in the Pristionchus (as of 2024), and the Eulimnadia comprises over 50 androdioecious . The taxonomic distribution of androdioecy is broad yet sparse, spanning diverse lineages such as (including and clam shrimps), nematodes in the order , and scattered families. It is notably absent from major vertebrate classes, with only rare exceptions in chordates like the mangrove Kryptolebias marmoratus. Most documented cases cluster in isolated or specialized environments, particularly marine habitats where sessile lifestyles or broadcast spawning may facilitate the persistence of males alongside hermaphrodites. The rarity of androdioecy stems in part from its theoretical instability, as mathematical models indicate that males can only invade and persist in hermaphroditic populations if their siring success through female gametes exceeds that of hermaphrodites by at least a factor of two. This stringent condition for male fitness advantage limits the system's stability in most ecological contexts. first noted this breeding system in 1877, highlighting its unusual nature in The Different Forms of Flowers on Plants of the Same Species, and subsequent surveys have consistently affirmed its low prevalence across taxa.

Comparison to Dioecy and Gynodioecy

Androdioecy differs from , which consists exclusively of separate male and female individuals with no hermaphrodites, in that enforces obligatory and eliminates self-fertilization entirely. In androdioecy, the presence of hermaphrodites permits selfing, which can lower mate-location costs in sparse populations but heightens risks of compared to the outcrossing mandate of . Gynodioecy represents a structural mirror to androdioecy, featuring females alongside hermaphrodites rather than males, and it prioritizes fitness gains through enhanced production in females via resource reallocation from . In contrast, androdioecy underscores specialization in males for export and dispersal, though this often yields smaller relative advantages due to the dispersed nature of pollen compared to more localized transmission biases that favor . prevails more frequently in flowering plants, documented in less than 1% of species, while androdioecy affects far fewer, largely because female-sterile mutations (leading to males) face steeper invasion barriers than male-sterile ones (leading to females). Evolutionarily, androdioecy can act as a transitional stage toward by successive loss of female function in hermaphrodites or reversion from via male-fertile mutants, paralleling the more documented -to- route but occurring less often due to pollen competition constraints. Fitness trade-offs in androdioecy require hermaphrodites to apportion resources between roles, potentially diluting efficiency in both, whereas permits full specialization—maximizing in males and seeds in females—and boosts seed output in females at the cost of production. Stability in and often hinges on balanced sex ratios, ideally 1:1 in to equalize parental investment, while androdioecy demands males exceed hermaphrodite output by at least twofold to persist against selfing advantages in populations.

Comparison to Hermaphroditism and Monoecy

Androdioecy represents a polymorphic sexual system characterized by the coexistence of male individuals, which perform only male functions, and hermaphroditic individuals, which perform both male and female functions, within the same population. In contrast, pure hermaphroditism involves all individuals possessing both male and female reproductive capabilities, enabling options for self-fertilization or outcrossing based on compatibility and environmental factors. This uniformity in hermaphroditism simplifies mating dynamics but can lead to inbreeding depression if selfing predominates, whereas androdioecy introduces dedicated males that can enhance outcrossing rates by providing diverse pollen sources, though this polymorphism complicates reproductive interactions and requires males to achieve at least twice the siring success of hermaphrodites to invade and maintain in a population. Monoecy, prevalent among certain lineages, differs fundamentally from androdioecy in its organization at the individual level, where separate unisexual and female flowers develop on the same , allowing controlled allocation of resources to each function without population-level dimorphism. Androdioecy, by , operates through discrete and hermaphroditic individuals across the , promoting greater flexibility in sex expression but demanding coordinated evolutionary pressures to sustain both morphs. While reduces self-pollination risks through temporal or spatial separation of flowers on a single individual, androdioecy relies on inter-individual interactions that can amplify dispersal in heterogeneous environments. One key advantage of hermaphroditism and lies in their provision of reproductive assurance, particularly in sparse or colonizing populations where mates may be scarce, as self-fertilization or ensures seed production without reliance on external pollinators or partners. Androdioecy, however, may confer benefits in pollen flow by leveraging s for broader dispersal, potentially mitigating in dense or mobile populations, but it carries the disadvantage of morph extinction if their relative does not sufficiently compensate for the lack of female function, leading to reversion to hermaphroditism. Hermaphroditism dominates as the ancestral and most common , accounting for approximately 90% of angiosperm and being widespread among sessile or low-mobility animals such as sponges and corals, where simultaneous or sequential dual functionality maximizes reproductive opportunities in stable habitats. Androdioecy is considerably rarer, confirmed in about 50 plant and approximately 115 , and tends to occur in taxa with clonal growth or enhanced mobility that facilitate the persistence of polymorphic populations. Like , androdioecy functions as an intermediate polymorphic system between hermaphroditism and separate sexes.

Evolution

Evolutionary Pathways

Androdioecy has evolved through two primary ancestral routes: from hermaphroditic ancestors via the emergence of males that suppress female reproductive function, and from dioecious ancestors via the acquisition of male function in females, leading to hermaphrodites. These pathways reflect adaptations to specific selective pressures, such as dynamics and . The pathway from hermaphroditism involves the of males through genetic modifiers that inhibit female gamete production or function in a of individuals, while hermaphrodites retain both sexual functions. This transition is often favored when self-fertilization in hermaphrodites leads to , reducing offspring fitness, or when males gain a in pollen export under high-density conditions with intense pollen . In such scenarios, males can sire more outcrossed progeny, promoting . This route is theoretically viable but less frequently documented in phylogenies compared to the reverse pathway. In contrast, the pathway from is more commonly observed and typically arises when hermaphrodites invade dioecious populations by restoring male fertility to females, often through mechanisms like or the development of functional production. This is driven by limitation in sparse or colonizing populations, where self-compatible hermaphrodites provide reproductive assurance by enabling self-fertilization when mates are scarce, thereby increasing seed set despite potential costs to . Once established, males may persist if they offer superior dispersal or siring success. Phylogenetic evidence supports these transitions across taxa. In plants, androdioecy in the Datiscaceae family, exemplified by Datisca glomerata, originated from a dioecious ancestor, as inferred from chloroplast DNA restriction site mapping that places it within a clade of dioecious relatives. In animals, the crustacean genus Eulimnadia exhibits ancient androdioecy derived from dioecy, with at least two independent shifts within the Limnadiidae family documented through molecular phylogenies and biogeographical analysis, persisting for 24–180 million years. These cases highlight repeated evolutionary lability in sexual systems. Transitions to androdioecy are infrequent overall, but phylogenetic reconstructions indicate that origins from dioecious ancestors predominate, with androdioecy serving as a transient intermediate stage often progressing toward full dioecy or hermaphroditism due to its inherent instability.

Theoretical Models for Stability

Theoretical models for the stability of androdioecy primarily focus on the conditions under which males can invade and coexist with hermaphrodites in populations derived from hermaphroditism, emphasizing the role of selfing rates, relative male fitness gains, and inbreeding depression. In the seminal model by Charlesworth and Charlesworth (1978), males can invade a hermaphroditic population only if their relative male fertility is at least twice that of the hermaphrodites' male function (rm ≥ 2), due to the twofold transmission advantage of hermaphrodites via both gamete types. These conditions assume inbreeding depression on selfed progeny (δ > 0.5); without it, males cannot invade selfing populations due to the hermaphrodites' full transmission via selfing. Stability of the polymorphism requires selfing rates exceeding 0.5, as high selfing reduces the effective male fitness gain needed for males to persist by limiting outcross pollen competition from hermaphrodites. This threshold arises from the fitness-gain curve for male function, which becomes steeper under partial inbreeding, making androdioecy viable primarily in self-compatible systems. Lloyd's pollen discounting model extends this framework specifically to , where androdioecy evolves if males provide superior export to compensate for the lack of female function. discounting refers to the reduction in outcross seed set in due to self- interference, favoring males with higher dispersal efficiency. In this model, selfing reduces the effective male success of , lowering the required relative male fertility rm threshold from >2 (for ) toward >1 (for high selfing), facilitating male invasion. This model predicts that androdioecy is most stable in species with geitonogamous selfing, where within-plant movement further discounts male success. Metapopulation dynamics provide an additional explanation for androdioecy persistence in structured habitats, even when single populations are unstable. In Pannell's (2002) model, local subpopulations experience and recolonization, allowing males to maintain polymorphism through differential dispersal; males, with higher seed production potential via , contribute more to recolonization, countering local losses from selfing-biased hermaphrodites. This process reduces average male frequency across the but stabilizes the system in fragmented environments like islands or temporary ponds. Non-adaptive mechanisms, such as in small populations, can also sustain androdioecy by preventing fixation of hermaphrodites despite weak selection. Cyto-nuclear interactions, including linked to nuclear restorers, may maintain polymorphism through epistatic balance, particularly in systems with maternal of . Empirical tests of these models confirm their predictions of rarity, as androdioecy occurs in fewer than 50 angiosperm , mostly with selfing rates above 0.5, aligning with the high thresholds for stability. In low-selfing , models fail to explain persistence, with males often absent or unstable, as observed in clades where hermaphrodites dominate due to insufficient pollen advantages. Field studies, such as those in , validate effects by showing higher male frequencies in colonizing populations.

Mechanisms

Genetic Mechanisms

In androdioecious species, nuclear inheritance often governs sex expression through XY-like chromosomal systems, where the or equivalent carries dominant alleles that suppress female reproductive function, resulting in development. This mechanism is prevalent in animals, particularly nematodes, where hermaphrodites are typically XX and males are XO, with the absence of a second promoting traits via dosage-dependent regulation of sex-determining genes like tra-1. In arthropods, such as the Icerya purchasi, contributes to androdioecy, with diploid hermaphrodites arising from fertilized eggs and haploid males from unfertilized ones, allowing maintenance of both morphs through differential fitness advantages in selfing versus . Similar XY systems occur in , where the Y-linked female-suppressor (Su F) prevents carpel development in males, as seen in dioecious relatives, though androdioecy in like species shows a strong genetic basis without full Y degeneration. Recent genomic studies in Tapiscia sinensis identify expanded Y-linked genes suppressing female function, supporting this system. Cytoplasmic factors play a role in some androdioecious systems via maternally inherited mitochondrial genes that induce sterility in one function, countered by nuclear restorers to produce viable hermaphrodites. For instance, (CMS) variants can interact with nuclear genes to limit production in certain lineages, but in androdioecy, analogous cytoplasmic female sterility is rare and mostly theoretical, with nuclear control predominant in families like . Such interactions prevent fixation of sterility and support polymorphism, though cytoplasmic effects are less common than nuclear control in stable androdioecy. Environmental sex determination modulates nuclear cues in some androdioecious animals, particularly nematodes, where or influences the development of males versus hermaphrodites. In species like Pristionchus mayeri and P. entomophagus, higher s (e.g., 25°C) elevate male frequencies from near 0% to about 1.5% by altering processes in XX individuals, potentially via thermosensitive of conserved factors like TRA-1. Density-dependent effects, such as resource scarcity at high populations, similarly bias toward males in nematodes like Auanema freiburgensis, integrating environmental signals with genetic pathways to adjust sex ratios dynamically. The maintenance of male-hermaphrodite polymorphism in androdioecy relies on balancing selection through negative , where rare morphs gain reproductive advantages, often involving polygenic traits rather than single loci. In , this mirrors dynamics, with favoring males when hermaphrodites self-fertilize excessively, preserving diversity via rare-allele benefits; polygenic control distributes effects across multiple QTLs to stabilize equilibria. No single locus typically dominates, allowing adaptive responses to varying conditions without evolutionary instability. Specific genetic loci exemplify these mechanisms; in plants, quantitative trait loci (QTLs) for male function and female sterility have been identified in Fraxinus species, contributing to the strong heritable component of sex expression, though exact mapping remains limited. In animals, sex-ratio distorters in crustaceans like clam shrimps (Eulimnadia spp.) involve genetic elements that skew offspring ratios toward males, enhancing outcrossing in androdioecious populations via nuclear variants influencing gamete competition.

Functional and Physiological Aspects

In androdioecious populations, males typically exhibit enhanced male reproductive function to compensate for the absence of female , often producing significantly higher quantities of or compared to hermaphrodites. For instance, in the Phillyrea angustifolia, males allocate more resources to flowering intensity, resulting in greater total output despite similar per , which confers a advantage of approximately twofold in siring seeds within a season. In animal systems, such as nematodes, males may evolve specialized structures for efficient dispersal, enhancing competitive success in . This specialization allows males to achieve higher transmission success through male gametes, though they remain vulnerable to competition from hermaphrodite or in shared pools. Hermaphrodites in androdioecious species perform both functions, either simultaneously or sequentially, with selfing rates varying widely from near 0% to as high as 80% depending on ecological context and genetic factors. Low selfing rates predominate in many stable populations, where via males helps mitigate by promoting in progeny. In like ornus, selfing occurs facultatively but decreases with higher male frequencies and , leading to rates of approximately 90%. , such as protandry (male function preceding female) or protogyny (female preceding male), is common in hermaphrodites to reduce and favor cross-fertilization. These patterns ensure that male-hermaphrodite matings produce outcrossed offspring with hybrid vigor, enhancing overall population fitness. Mating dynamics in androdioecy emphasize interactions between males and hermaphrodites, where protandrous or protogynous timing in hermaphrodites minimizes selfing and maximizes opportunities for or from males to fertilize ovules. In such systems, males often sire a disproportionate share of outcrossed progeny, as seen in nematodes like , where males can mate with hermaphrodites to preferentially produce outcrossed progeny. This promotes outcrossed progeny that exhibit superior viability and growth due to . However, hermaphrodites can self-fertilize as a reproductive assurance mechanism in low-density conditions, balancing the benefits of with selfing reliability. Fitness allocation in androdioecious individuals reflects trade-offs between sexual functions, with hermaphrodites dividing resources between gamete production—ideally approaching a 50:50 ratio in theoretical models but often skewed by environmental constraints. Males, by contrast, allocate fully to male function, enabling specialization but exposing them to risks like pollen or from hermaphrodites. In , males produce about 12 times more per than hermaphrodites, underscoring this reallocation for competitive edge. Hermaphrodites face opportunity costs, such as reduced growth or when investing in both sexes, which can limit their overall fitness relative to specialized males in male-biased scenarios. Experimental studies confirm key functional outcomes, including higher seed set and progeny viability from outcrosses compared to selfed offspring in hermaphrodites, primarily due to inbreeding depression. In Datisca glomerata, outcrossed seeds show elevated germination and survival rates, supporting male maintenance by enhancing the value of their contributions. Stable populations often maintain male frequencies between 10% and 50%, as observed across diverse taxa like Fraxinus species and clam shrimp, where this range balances selfing assurance with outcrossing benefits. These frequencies correlate with low hermaphrodite selfing and sufficient male fertility advantages, ensuring population persistence.

Examples

In Animals

Androdioecy, characterized by the coexistence of males and hermaphrodites in a population, is rare among animals but documented in several phyla, particularly those with self-fertilizing hermaphrodites that benefit from occasional facilitated by males. In the phylum Nematoda, androdioecy is well-studied in species of the genus Caenorhabditis, such as C. elegans and C. briggsae. These nematodes feature self-fertilizing hermaphrodites that produce nearly all-female (hermaphroditic) progeny, with males occurring at low frequencies (typically 0.1-0.2%) to enable and introduce . High selfing rates (>99%) in hermaphrodites maintain the system, while males persist due to advantages in and potential escape from deleterious mutations in selfing lineages. Within Arthropoda, androdioecy is prominent in certain crustaceans and cirripedes. The genus Eulimnadia (e.g., E. texana and E. agassizii), in the family Limnadiidae, exhibits this system, with hermaphrodites capable of self-fertilization and males comprising 10-30% of populations in some species. This ancient reproductive mode has persisted for 24-180 million years, likely originating from a , and is maintained in ephemeral freshwater habitats where enhances adaptability. determination in these branchiopods involves genetic factors, with no evidence of . In (Cirripedia), over 30 species across multiple lineages display androdioecy, featuring dwarf complemental males that reside within or near hermaphroditic individuals to provide sperm in dense, sessile colonies. This system has evolved independently at least four times, promoting stability through local mate competition in constrained environments. Androdioecy is rarer in other phyla but occurs in Chordata, notably the fish Kryptolebias marmoratus (). This species consists of selfing hermaphrodites that produce clonal lineages via internal self-fertilization, alongside males induced by environmental factors like temperature or genetic triggers, occurring at frequencies up to 7% in wild populations. Males facilitate , countering in isolated mangrove habitats, with evidence of significant despite predominant selfing. Overall, androdioecious animal species are predominantly marine or freshwater , with males serving to enhance in populations dominated by clonal or highly selfing hermaphrodites, often in low-density or isolated settings. This pattern underscores androdioecy's role as a transitional or stable strategy derived from either hermaphroditic or dioecious ancestors, contrasting with its scarcity in vertebrates.

In Plants

Androdioecy is exceedingly rare among angiosperms, with approximately 50 species documented across flowering plants, representing a small fraction of the diverse sexual systems observed in this group. In these species, populations consist of male individuals producing only pollen and hermaphrodites bearing both functional male and female organs, often with floral dimorphism that enhances pollen dispersal or seed production. This system typically arises in self-compatible lineages where males provide a genetic advantage by promoting outcrossing, though it requires specific conditions for stability, such as high male fertility relative to hermaphrodites. A classic example is Datisca glomerata (Datiscaceae), a perennial herb native to western North America. Males produce staminate flowers lacking functional pistils, while hermaphrodites have perfect flowers with both stamens and pistils; notably, male flowers possess approximately 3.8 times as many fertile anthers as those of hermaphrodites, conferring a substantial production advantage. Sex determination in D. glomerata is under nuclear genetic control, with no evidence of cytoplasmic factors, and male frequencies approach 50% in natural populations, supporting the functionality of this system. Several species in the genus (Oleaceae), such as F. lanuginosa and F. ornus, also display androdioecy, particularly among wind-pollinated trees in temperate regions. In these ashes, males bear only staminate inflorescences, while hermaphrodites produce bisexual flowers, though with reduced male function compared to males; pollen limitation in sparse populations drives the selective maintenance of males by improving siring success. Mating system analyses confirm mixed outcrossing and selfing in hermaphrodites, with male frequencies often exceeding 50% in some populations due to environmental constraints on pollen flow. Another notable case is Mercurialis annua (Euphorbiaceae), an annual herb with functional androdioecy in polyploid populations, where males coexist with hermaphrodites; however, recent studies have documented widespread male sterility leading to trioecy (presence of females) in some regions, influenced by genetic and environmental factors. Tapiscia sinensis (Tapisciaceae), a rare endemic tree in China, exhibits functional androdioecy with male and hermaphroditic individuals; genomic analyses reveal adaptations like male-linked genes supporting pollen production, and hermaphrodites are self-compatible. Androdioecy occurs sporadically across angiosperm families, predominantly in , shrubs, or trees in temperate or subtropical zones; notable occurrences include multiple in . Ecologically, these are frequently associated with disturbed habitats, where males enhance rates in self-compatible hermaphrodites, leading to variable male frequencies of 20–60% depending on and availability. Phylogenetically, androdioecy has evolved independently multiple times from hermaphroditic ancestors, often as a transient state toward , without dominating any particular lineage. In contrast to certain animal groups where it is more prevalent, this system remains unusually scarce in plants.

References

  1. https://www.nature.com/articles/srep35022
  2. https://www.nature.com/articles/nrg776
  3. https://www.nature.com/articles/343641a0
  4. https://www.nature.com/articles/s41438-020-00414-w
  5. https://www.nature.com/articles/s41467-024-53854-6
  6. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/androdioecy
  7. https://www.collinsdictionary.com/us/dictionary/english/androdioecious
  8. https://academic.oup.com/icb/article/46/4/449/635378
  9. https://besjournals.onlinelibrary.wiley.com/doi/10.1046/j.1365-2435.2002.06893.x
  10. https://www.journals.uchicago.edu/doi/10.1086/380493
  11. https://www.jstor.org/stable/2460930
  12. https://academic.oup.com/mollus/article-abstract/90/2/eyae017/7675035
  13. https://bsapubs.onlinelibrary.wiley.com/doi/10.3732/ajb.1400196
  14. https://etd.ohiolink.edu/acprod/odb_etd/ws/send_file/send?accession=akron1637261675658712&disposition=inline
  15. https://pubmed.ncbi.nlm.nih.gov/21672757/
  16. https://nph.onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2007.02228.x
  17. https://royalsocietypublishing.org/doi/10.1098/rsbl.2009.0142
  18. https://www.journals.uchicago.edu/doi/abs/10.1086/283342
  19. https://doi.org/10.1093/aob/mcp141
  20. https://www.journals.uchicago.edu/doi/full/10.1086/684260
  21. https://www.annualreviews.org/doi/pdf/10.1146/annurev.ecolsys.33.010802.150419
  22. https://www.nature.com/articles/hdy197883.pdf
  23. https://royalsocietypublishing.org/doi/10.1098/rstb.2015.0541
  24. https://onlinelibrary.wiley.com/doi/10.1111/j.1558-5646.2012.01714.x
  25. https://bmcplantbiol.biomedcentral.com/articles/10.1186/s12870-019-2081-7
  26. https://www.jstor.org/stable/2419526
  27. https://onlinelibrary.wiley.com/doi/10.1111/j.1420-9101.2009.01813.x
  28. https://pmc.ncbi.nlm.nih.gov/articles/PMC11796466/
  29. https://onlinelibrary.wiley.com/doi/10.1111/evo.14346
  30. https://www.nature.com/articles/6800016
  31. https://pmc.ncbi.nlm.nih.gov/articles/PMC1383628/
  32. https://www.nature.com/articles/s41437-024-00729-7
  33. https://pmc.ncbi.nlm.nih.gov/articles/PMC11544036/
  34. https://www.biorxiv.org/content/10.1101/862664v1.full-text
  35. https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.12441
  36. https://bsapubs.onlinelibrary.wiley.com/doi/10.3732/ajb.90.6.949
  37. https://pmc.ncbi.nlm.nih.gov/articles/PMC8391622/
  38. https://pmc.ncbi.nlm.nih.gov/articles/PMC10902885/
  39. https://www.nature.com/articles/6800043
  40. https://pmc.ncbi.nlm.nih.gov/articles/PMC1462032/
  41. https://bsapubs.onlinelibrary.wiley.com/doi/full/10.1002/ajb2.16429
  42. https://www.mdpi.com/2223-7747/11/6/753
  43. https://pages.uoregon.edu/pphil/pubs/stewart2002.pdf
  44. https://www.sciencedirect.com/science/article/abs/pii/S0022098110001309
  45. https://pmc.ncbi.nlm.nih.gov/articles/PMC1502555/
  46. https://www.sciencedirect.com/science/article/abs/pii/S0168945225002845
  47. https://www.journals.uchicago.edu/doi/abs/10.1086/314088
  48. https://www.sciencedirect.com/science/article/pii/S0960982220318807
  49. https://nph.onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2004.01242.x
  50. https://academic.oup.com/evolut/article/71/4/898/6725961
Add your contribution
Related Hubs
User Avatar
No comments yet.