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m Task 19: convert/update IUCN references to {{cite iucn}} using data from IUCN Red List API; IUCN status confirmed; IUCN status ref updated [duplicates removed (2×)]; evaluated 1 reference; 1 reference modified; evaluated 1 template; 1 template modified; (4/00:10.53);
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{{Short description|Species of plant}}
{{Short description|Species of cycad}}
{{Speciesbox
{{Speciesbox
| image = Cycas micronesica photo courtesy A. Gawel (15391498081).jpg
| image = Cycas micronesica photo courtesy A. Gawel (15391498081).jpg
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| status = EN
| status = EN
| status_system = IUCN3.1
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 13 November 2021">{{cite iucn |author=Marler, T. |author2=Haynes, J. |author3=Lindstrom, A. |date=2010 |title=''Cycas micronesica'' |volume=2010 |page=e.T61316A12462113 |doi=10.2305/IUCN.UK.2010-3.RLTS.T61316A12462113.en |access-date=13 November 2021}}</ref>
| status_ref = <ref name=iucnredlist>{{cite iucn |author=Bösenberg, J.D.|year=2022|title=''Cycas micronesica''|page=e.T61316A68906033|doi=10.2305/IUCN.UK.2022-1.RLTS.T61316A68906033.en|access-date=22 August 2023}}</ref>
| genus = Cycas
| genus = Cycas
| species = micronesica
| species = micronesica
| authority = [[Ken Hill (botanist)|K.D. Hill]], 1994
| authority = [[Ken Hill (botanist)|K.D. Hill]], 1994
}}
}}
⚫
'''''Cycas micronesica''''' is a species of [[cycad]] found on the island of [[Yap]] in [[Micronesia]], the [[Marianas]] islands of [[Guam]] and [[Rota (island)|Rota]], and [[Palau|The Republic of Palau]]. It is commonly known as '''federico nut''' or ''fadang'' in [[Chamorro language|Chamorro]]. The species, previously lumped with ''[[Cycas rumphii]]'' and ''[[Cycas circinalis]]'', was described in 1994 by [[Ken Hill (botanist)|Ken Hill]].<ref>Hill, K.D. (1994). ''Cycas micronesica''. ''Australian Systematic Botany'' '''7''': 554-556.</ref> [[Paleoecology|Paleoecological]] studies have determined that ''C. micronesica'' has been present on the island of [[Guam]] for about 9,000 years.<ref>Athens, J., & Ward, J. (2004). Holocene vegetation, savanna origins and human settlement of Guam. ''Records Of The Australian Museum,'' 15-30.</ref> It is linked with [[Lytico-Bodig disease]], a condition similar to [[amyotrophic lateral sclerosis]] (ALS), due to the [[neurotoxin]] [[BMAA]] found in its seeds, which were a traditional food source on [[Guam]] until the 1960s.<ref>Sacks, Oliver. (1996). ''The Island of the Colour-blind''. Pan Macmillan Australia: Sydney. {{ISBN|0-330-35887-1}}</ref> The neurotoxin is present due to its symbiosis with [[cyanobacteria]].<ref name="Cox">{{cite journal |vauthors=Cox PA, Banack SA, Murch SJ, Rasmussen U, Tien G, Bidigare RR, Metcalf JS, Morrison LF, Codd GA, Bergman B |year=2005 |title=Diverse taxa of cyanobacteria produce b-N-methylamino-L-alanine, a neurotoxic amino acid |journal=PNAS |volume=102 |issue=14 |pages=5074–5078 |bibcode=2005PNAS..102.5074C |doi=10.1073/pnas.0501526102 |pmc=555964 |pmid=15809446 |doi-access=free}}</ref><ref name="Esterhuizen">{{cite journal |vauthors=Esterhuizen M, Downing TG |year=2008 |title=β-N-methylamino-L-alanine (BMAA) in novel South African cyanobacterial isolates |journal=Ecotoxicology and Environmental Safety |volume=71 |issue=2 |pages=309–313 |doi=10.1016/j.ecoenv.2008.04.010 |pmid=18538391}}</ref>
⚫
[[File:Understory habitation of C. micronesica.jpg|thumb|left|Understory habitation of C. micronesica.Image by Lauren Gutierrez.|249x249px]]

⚫
'''''Cycas micronesica''''' is a type of [[cycad]] found in the island of [[Yap]] in [[Micronesia]], the [[Marianas]] islands of [[Guam]] and [[Rota (island)|Rota]], and [[Palau|The Republic of Palau]]. It is commonly known as Federico nut or Fadang in [[Chamorro language|Chamorro]]. The species, previously lumped with ''[[Cycas rumphii]]'' or ''[[Cycas circinalis]]'', was described in 1994 by [[Ken Hill (botanist)|Ken Hill]].<ref>Hill, K.D. (1994). ''Cycas micronesica''. ''Australian Systematic Botany'' '''7''': 554-556.</ref> [[Paleoecology|Paleoecological]] studies have determined that ''C. micronesica'' has been present on the island of [[Guam]] for about 9,000 years.<ref>Athens, J., & Ward, J. (2004). Holocene vegetation, savanna origins and human settlement of Guam. ''Records Of The Australian Museum,'' 15-30.</ref> It is linked with the human degenerative disease [[Lytico-Bodig disease]], which is similar to [[amyotrophic lateral sclerosis]] (ALS) through a [[neurotoxin]] ([[BMAA]]) in the seeds (due to symbiosis with [[cyanobacteria]]<ref name=Cox>{{cite journal | authors = Cox, PA, Banack, SA, Murch, SJ, Rasmussen, U, Tien, G, Bidigare, RR, Metcalf, JS, Morrison, LF, Codd, GA, Bergman, B. | year = 2005 | title = Diverse taxa of cyanobacteria produce b-N-methylamino-L-alanine, a neurotoxic amino acid | journal = PNAS | volume = 102 | issue = 14 | doi = 10.1073/pnas.0501526102 | pmid=15809446 | pmc=555964 | pages=5074–5078| doi-access = free }}</ref><ref name=Esterhuizen>{{cite journal | authors = Esterhuizen, M, Downing, TG. | year = 2008 | title = β-N-methylamino-L-alanine (BMAA) in novel South African cyanobacterial isolates | journal = Ecotoxicology and Environmental Safety | volume = 71 | issue = 2 | doi = 10.1016/j.ecoenv.2008.04.010 | pmid = 18538391 | pages=309–313}}</ref>), which were a traditional food source on [[Guam]] until the 1960s.<ref>Sacks, Oliver. (1996). ''The Island of the Colour-blind''. Pan Macmillan Australia: Sydney. {{ISBN|0-330-35887-1}}</ref>


==Description==
==Description==
⚫
''Cycas micronesica'' is a medium-sized tree most commonly 2–5 meters tall but can reach heights up to 15 meters. The tree has a straight palm like trunk ringed with frond scars.<ref>Vogt, S., & Williams, L. (2004). Common flora & fauna of the Mariana Islands. Saipan?: S.R. Vogt & L.L. Williams.</ref>
[[File:Fadang Leaves.jpg|thumb|left|<ref>{{Cite news|url=https://www.flickr.com/photos/guam-flora-fauna/albums/72157629711588241/with/7100633045/|title=Cycas micronesica K.D.Hill|work=Flickr|access-date=2018-06-02|language=en-us}}</ref> Pinnate leaf formation <ref>{{Cite web|url=https://www.flickr.com/photos/guam-flora-fauna/albums/72157629711588241/with/7100633045/|title=Cycas micronesica K.D. Hill|last=Gutierrez|first=Lauren|date=2010-08-30|website=Flikr|archive-url=|archive-date=|access-date=06/01/2018}}</ref> Image by Lauren Gutierrez.|143x143px]]
⚫
A medium-sized tree most commonly 2–5 meters tall but can reach heights up to 15 meters. The tree has a straight palm like trunk ringed with frond scars.<ref>Vogt, S., & Williams, L. (2004). Common flora & fauna of the Mariana Islands. Saipan?: S.R. Vogt & L.L. Williams.

</ref>
⚫
[[File:Stem of C. micronesica.jpg|thumb|Stem and palm-like structure. Image by Lauren Gutierrez.]]


===Leaves===
===Leaves===
Leaves are 140–180&nbsp;cm long, flat in section (opposing pinnae inserted at 180 degrees on rhachis), with 130 -150 pinnae, terminated by a spine c. 4mm long; petiole usually glabrous, usually unarmed, rarely [[spinescent]] for up to 20% of length, 35 – 45&nbsp;cm long; median pinnae at 70-80 degrees to rhachis, 240 – 280&nbsp;mm long, 16 –17&nbsp;mm wide, 0.35 - 0.45&nbsp;mm thick, glabrous, dull green or slightly bluish-green when developing, becoming glossy mid-green at maturity, flat in section with slightly recurved margins, strongly discolorous, decurrent for 7–10&nbsp;mm, narrowed to 5.0-6.0&nbsp;mm at base, 17 – 20&nbsp;mm apart on rhachis apex attenuate; midrib not sharply raised, more or less equally prominent above and below, 1.2 -1.5&nbsp;mm wide.<ref name=":0">{{Cite journal|last=Hill|first=K. D.|date=1994|title=The Cycas rumphii complex (Cycadaceae) in New Guinea and the western Pacific|url=http://www.publish.csiro.au/SB/SB9940543|journal=Australian Systematic Botany|language=en|volume=7|issue=6|pages=543–567|doi=10.1071/sb9940543|issn=1446-5701}}</ref>
Leaves are 140–180&nbsp;cm long, flat in section (opposing pinnae inserted at 180 degrees on rhachis), with 130 -150 pinnae, terminated by a spine c. 4mm long; petiole usually glabrous, usually unarmed, rarely [[spinescent]] for up to 20% of length, 35 – 45&nbsp;cm long; median pinnae at 70-80 degrees to rachis, 240 – 280&nbsp;mm long, 16 –17&nbsp;mm wide, 0.35 - 0.45&nbsp;mm thick, glabrous, dull green or slightly bluish-green when developing, becoming glossy mid-green at maturity, flat in section with slightly recurved margins, strongly discolorous, decurrent for 7–10&nbsp;mm, narrowed to 5.0-6.0&nbsp;mm at base, 17 – 20&nbsp;mm apart on rhachis apex attenuate; midrib not sharply raised, more or less equally prominent above and below, 1.2 -1.5&nbsp;mm wide.<ref name=":0">{{Cite journal|vauthors=Hill KD |date=1994|title=The Cycas rumphii complex (Cycadaceae) in New Guinea and the western Pacific |journal=Australian Systematic Botany |language=en|volume=7|issue=6|pages=543–567 |doi=10.1071/sb9940543|issn=1446-5701 |url=http://www.publish.csiro.au/SB/SB9940543}}</ref>

⚫
===Reproductive organs===
⚫
Like all [[Cycad|cycads]], ''Cycas micronesica'' are [[Dioecy|dioecious]]. Females possess clusters of [[ovule]]s situated on modified leaves called [[Megasporangia|megasporophylls]]. Male reproductive structures consist of modified leaves called [[Microsporangia|microsporophylls]], but each modified leaf has small, compact pollen sacks attached to their lower surface.<ref>Willis, K., & McElwain, J. C. (2014). The evolution of plants (2nd ed.). Oxford, United Kingdom; New York: Oxford University Press.</ref> There has been documentation of the symbiotic relationship the Guamanian ''C. micronesica'' with [[Anatrachyntis|Anatrachyntis sp.]], which depends on male cones ([[microsporangia]]) for [[oviposition]] and recruitment in return for pollinating the species.


⚫
===Reproductive Organs===
⚫
[[File:Female reproductive structures.jpg|thumb|left|Female reproductive structures (megasporangia). Image by Thomas Marler |168x168px]]
⚫
[[File:Megasporngia of C. micronesica.jpg|thumb|left|Male cones (microsporangia) <ref>{{Cite web|url=http://www.gpepp.org/|title=Home|website=Guam Plant Extinction Prevention Program|language=en-US|access-date=2018-06-08}}</ref>|211x211px]]
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[[File:C. micronesica seeds.jpg|thumb|Developed seed of C. micronesica. Image from Thomas Marler.]]
⚫
Cycads, being [[gymnosperm]]s, are [[Dioecy|dioecious]] organisms. Females possess clusters of [[ovule]]s situated on modified leaves called [[Megasporangia|megasporophylls]]. Male reproductive structures also consist of modified leaves called [[Microsporangia|microsporophylls]], but each modified leaf have small, compact pollen sacks attached to their lower surface.<ref>Willis, K., & McElwain, J. C. (2014). The evolution of plants (Second ed.). Oxford, United Kingdom ; New York: Oxford University Press.
</ref> There has been documentation of the symbiotic relationship the Guamanian ''C. micronesica'' with [[Anatrachyntis|Anatrachyntis sp.]], which depends on male cones ([[microsporangia]]) for [[oviposition]] and recruitment in return for pollinating the species.
⚫
[[File:CMicronesica.jpg|thumb|Fertilized megasporangia with developing seeds. Image by Lauren Gutierrez.]]
The microsporangiate cones are pale fawn to pale orange-brown, narrowly ovoid, 30–50&nbsp;cm long, 8–10&nbsp;cm in diameter. [[Microsporangia|Microsporophyll]] lamina are 35–45&nbsp;mm long, 20–25&nbsp;mm wide; fertile zone 25–35&nbsp;mm long; sterile apex 7–10&nbsp;mm long, not recurved, apical spine somewhat reduced, broad, sharply upturned, 2&nbsp;mm long. [[Megasporangia|Megasporophylls]] 27–33&nbsp;cm long, grey- and orange-tomentose, with 2-6 ovules, lamina 45–55&nbsp;mm wide, broadly ovate to elliptical, regularly dentate with 16-20 lateral spines, apical spine 8–15&nbsp;mm long, lateral spines 2–6&nbsp;mm long. Seeds flatten to ovoid, green becoming orange, not pruinose, 50–60&nbsp;mm long, 45–50&nbsp;mm in diameter; [[sarcotesta]] 3–6&nbsp;mm thick.<ref name=":0" />
The microsporangiate cones are pale fawn to pale orange-brown, narrowly ovoid, 30–50&nbsp;cm long, 8–10&nbsp;cm in diameter. [[Microsporangia|Microsporophyll]] lamina are 35–45&nbsp;mm long, 20–25&nbsp;mm wide; fertile zone 25–35&nbsp;mm long; sterile apex 7–10&nbsp;mm long, not recurved, apical spine somewhat reduced, broad, sharply upturned, 2&nbsp;mm long. [[Megasporangia|Megasporophylls]] 27–33&nbsp;cm long, grey- and orange-tomentose, with 2-6 ovules, lamina 45–55&nbsp;mm wide, broadly ovate to elliptical, regularly dentate with 16-20 lateral spines, apical spine 8–15&nbsp;mm long, lateral spines 2–6&nbsp;mm long. Seeds flatten to ovoid, green becoming orange, not pruinose, 50–60&nbsp;mm long, 45–50&nbsp;mm in diameter; [[sarcotesta]] 3–6&nbsp;mm thick.<ref name=":0" />


==Conservation==
==Conservation==
''Cycas micronesica'' is threatened by a combination of introduced species throughout the islands of [[Guam]] and [[Rota (island)|Rota]]. The most notable pest is the [[Diaspididae|diaspidid]] [[scale insect|scale]] ''[[Aulacaspis yasumatsui]]'', which was first recognized in [[Guam]] in December 2003.<ref>Terry, Irene; & Marler, Thomas. (2005). Paradise Lost? Tipping the scales against Guam’s ''Cycas micronesica''. ''The Cycad Newsletter'' '''28'''(3-4): 21-23.</ref> Other threats include cycad blue butterfly (''[[Luthrodes pandava]]''), the longhorn beetle (''[[Acalolepta marianarum]]'') which causes stem damage, the alien invasive snail ''[[Satsuma mercatoria]]'' which feeds on young leaflets, and habitat loss due to the growing human population.<ref name=iucnredlist/> Prior to the invasion of ''Aulacaspis yasumatsui'', it was one of the most abundant plants in Guam's forests.<ref>Donnegan, J., & Pacific Northwest Research Station. (2004). Guam's forest resources, 2002 (Resource bulletin PNW ; 243). Portland, OR: U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station.</ref> Plant mortality was so rapid that the species was Red Listed as Endangered in 2006, only three years after the devastating invasions began.<ref>{{cite journal|author1=Marler, T.E.|author2=Lawrence, J.H.|year=2012|title=Demography of ''Cycas micronesica'' on Guam following introduction of the armoured scale ''Aulacaspis yasumatsui''|journal=Journal of Tropical Ecology|volume=28|issue=3|pages=233-242|doi=10.1017/S0266467412000119}}</ref><ref>{{cite journal|author=Marler, T.E.|year=2010|title=Cycad mutualist offers more than pollen transport|journal=American Journal of Botany|volume=97|issue=5|pages=841-845|jstor=20700414}}</ref> Population counts in northwest Guam have declined from 686 individuals in early 2004 (before ''[[Aulacaspis yasumatsui]]'' reached this habitat) to 87 individuals in January 2007.<ref name=iucnredlist/> In 2004, ''[[Rhyzobius lophanthae]]'' was employed on [[Guam]] as a biological pest control and has lessened the population decline. However, they were ineffective on protecting cycad seedlings from ''Aulacaspis yasumatsui'' predation, as lack of seed vigor is one of the major factors contributing to ''C. micronesica'' decline.<ref>{{cite journal|author1=Marler, T.E.|author2=Miller, R.|author3=Moore, A.|year=2013|title=Vertical Stratification of Predation on ''Aulacaspis yasumatsui'' Infesting ''Cycas micronesica'' Seedlings|journal=HortScience|volume=48|issue=1|pages=60-62|doi=10.21273/HORTSCI.48.1.60|doi-access=free}}</ref> without effective action against the Aulacaspis scale, it may become critically endangered. It used to have stable populations across Micronesia, with Guam having the largest. However, the Aulacaspis scale invasion caused an 87% decline in the Guam subpopulation over ten years.<ref name=":1">{{Cite web |title=Redlist - Cycas micronesica |url=https://www.iucnredlist.org/species/61316/68906033}}</ref>

== Threats ==
The Cycad Aulacaspis scale, an invasive species from Southeast Asia, poses a significant threat to Cycas micronesica, resulting in substantial plant mortality. However, it's crucial to emphasize that the current plant mortality is not solely due to this scale. The introduction of the Cycad Blue Butterfly in 2005 and the intensified damage caused by pre-existing arthropod pests are additional severe threats to the already weakened cycad population. Longhorn beetles, especially Acalolepta marianarum, are responsible for many recent plant deaths due to stem damage. Moreover, the invasive snail Satsuma mercatoria has emerged as a new and significant threat by feeding on young leaflets. This change in herbivore behavior may be a result of the compromised ability of unhealthy cycad plants to synthesize chemicals that deter herbivores. These threats collectively imperil the survival of Cycas micronesica.<ref name=":1" />

==Gallery==
<gallery mode=packed heights=150>
⚫
File:Understory habitation of C. micronesica.jpg|Understory habitation
File:Fadang Leaves.jpg|Pinnate leaf formation
⚫
File:Stem of C. micronesica.jpg|Stem and palm-like structure
⚫
File:Female reproductive structures.jpg|Female reproductive structures (megasporangia)
File:Microsporangia of C. micronesica .jpg|Male cones (microsporangia)
⚫
File:CMicronesica.jpg|Fertilized megasporangia with developing seeds
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File:Infested cone of c micronesica.jpg|Infestation by the armored scale on the male cone
⚫
File:C. micronesica seeds.jpg|Developed seed
</gallery>


== See also ==
⚫
[[File:Infested cone of c micronesica.jpg|thumb|left|Infestation by the armored scale on the male cone. Image by Thomas Marler |159x159px]]
*[[List of endemic plants in the Mariana Islands]]
''Cycas micronesica'' is threatened by a combination of introduced species throughout the islands of [[Guam]] and [[Rota (island)|Rota]]. The most notably pest is the [[Diaspididae|diaspidid]] [[scale insect|scale]] ''[[Aulacaspis yasumatsui]]'', which was first recognized in [[Guam]] in December 2003.<ref>Terry, Irene; & Marler, Thomas. (2005). Paradise Lost? Tipping the scales against Guam’s ''Cycas micronesica''. ''The Cycad Newsletter'' '''28'''(3-4): 21-23.</ref> Other threats include Cycad Blue Butterfly, the longhorn beetle (''[[Dihammus marianarum]]'') which causes stem damage, the alien invasive snail ''Satsuma mercatorius'' which feeds on young leaflets, and habitat loss due to the growing human population.<ref name="iucn status 13 November 2021" /> Prior to the invasion of ''[[Aulacaspis yasumatsui|Aulacaspis yasumatsu]]'', it was one of the most abundant plant on Guam's forest.<ref>Donnegan, J., & Pacific Northwest Research Station. (2004). Guam's forest resources, 2002 (Resource bulletin PNW ; 243). Portland, OR: U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station.
</ref> Plant mortality was so rapid that the species was Red Listed as Endangered in 2006, only three years after the devastating invasions began .<ref>Marler, T., & Lawrence, J. (2012). Demography of Cycas micronesica on Guam following introduction of the armoured scale Aulacaspis yasumatsui. Journal of Tropical Ecology, 28(3), 233-242.
</ref><ref>Marler, T. (2010). Cycad mutualist offers more than pollen transport. American Journal of Botany, 97(5), 841-845.
</ref> Population counts in northwest Guam has declined from 686 individuals in early 2004 (before ''[[Aulacaspis yasumatsui]]'' reached this habitat) to 87 individuals in January 2007.<ref name="iucn status 13 November 2021" /> In 2004, ''[[Rhyzobius lophanthae]]'' was employed on [[Guam]] as a biological pest control and has lessened the population decline. However, they were ineffective on protecting cycad seedlings from ''[[Aulacaspis yasumatsui]]'' predation, as lack of seed vigor is one of the major factors contributing to C. micronesica decline.<ref>Marler, T., Miller, R., & Moore, A. (2013). Vertical Stratification of Predation on Aulacaspis yasumatsui Infesting Cycas micronesica Seedlings. ''HortScience,'' ''48''(1), 60-62.</ref>


==References==
==References==
Line 45: Line 48:


==External links==
==External links==
* [http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/cycadpg?taxname=Cycas+micronesica The Cycad Pages – ''Cycas micronesica'']
* [http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/cycadpg?taxname=Cycas+micronesica The Cycad Pages – ''Cycas micronesica''] {{Webarchive|url=https://web.archive.org/web/20140623202541/http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/cycadpg?taxname=Cycas+micronesica |date=2014-06-23 }}
*[http://cnas-re.uog.edu/guam-plants-botanical/?scientific-name%5B%5D=Cycas+micronesica&wpv_aux_current_post_id=757&wpv_view_count=974-TCPID757 <nowiki>Plants of Guam [Botanical]- University of Guam College of Natural Arts and Sciences</nowiki>]
*[http://cnas-re.uog.edu/guam-plants-botanical/?scientific-name%5B%5D=Cycas+micronesica&wpv_aux_current_post_id=757&wpv_view_count=974-TCPID757 <nowiki>Plants of Guam [Botanical]- University of Guam College of Natural Arts and Sciences</nowiki>]
*[https://www.flickr.com/photos/guam-flora-fauna/albums/72157629711588241 Flikr: Plants of Guam by Lauren Gutierrez - Cycas micronesica K.D. Hill]
*[https://www.flickr.com/photos/guam-flora-fauna/albums/72157629711588241 Flickr: Plants of Guam by Lauren Gutierrez - Cycas micronesica K.D. Hill]
*[http://www.gpepp.org/ Guam Plant Extinction Prevention Program]
*[http://www.gpepp.org/ Guam Plant Extinction Prevention Program]
⚫
{{Cite web |url=http://www.gpepp.org/ |title=Home |website=Guam Plant Extinction Prevention Program|access-date=2018-06-08}}


{{Taxonbar|from=Q2711674}}
{{Taxonbar|from=Q2711674}}
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[[Category:Cycas|micronesica]]
[[Category:Cycas|micronesica]]
[[Category:Flora of the Northwestern Pacific|Flora of Micronesia]]
[[Category:Flora of the Northwestern Pacific]]
[[Category:Plants described in 1994]]
[[Category:Plants described in 1994]]
[[Category:Flora of Guam]]
[[Category:Flora of Micronesia]]
[[Category:Flora of Palau]]

Latest revision as of 12:16, 1 January 2024

Cycas micronesica
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Gymnospermae
Division: Cycadophyta
Class: Cycadopsida
Order: Cycadales
Family: Cycadaceae
Genus: Cycas
Species:
C. micronesica
Binomial name
Cycas micronesica
K.D. Hill, 1994

Cycas micronesica is a species of cycad found on the island of Yap in Micronesia, the Marianas islands of Guam and Rota, and The Republic of Palau. It is commonly known as federico nut or fadang in Chamorro. The species, previously lumped with Cycas rumphii and Cycas circinalis, was described in 1994 by Ken Hill.[2] Paleoecological studies have determined that C. micronesica has been present on the island of Guam for about 9,000 years.[3] It is linked with Lytico-Bodig disease, a condition similar to amyotrophic lateral sclerosis (ALS), due to the neurotoxin BMAA found in its seeds, which were a traditional food source on Guam until the 1960s.[4] The neurotoxin is present due to its symbiosis with cyanobacteria.[5][6]

Description[edit]

Cycas micronesica is a medium-sized tree most commonly 2–5 meters tall but can reach heights up to 15 meters. The tree has a straight palm like trunk ringed with frond scars.[7]

Leaves[edit]

Leaves are 140–180 cm long, flat in section (opposing pinnae inserted at 180 degrees on rhachis), with 130 -150 pinnae, terminated by a spine c. 4mm long; petiole usually glabrous, usually unarmed, rarely spinescent for up to 20% of length, 35 – 45 cm long; median pinnae at 70-80 degrees to rachis, 240 – 280 mm long, 16 –17 mm wide, 0.35 - 0.45 mm thick, glabrous, dull green or slightly bluish-green when developing, becoming glossy mid-green at maturity, flat in section with slightly recurved margins, strongly discolorous, decurrent for 7–10 mm, narrowed to 5.0-6.0 mm at base, 17 – 20 mm apart on rhachis apex attenuate; midrib not sharply raised, more or less equally prominent above and below, 1.2 -1.5 mm wide.[8]

Reproductive organs[edit]

Like all cycads, Cycas micronesica are dioecious. Females possess clusters of ovules situated on modified leaves called megasporophylls. Male reproductive structures consist of modified leaves called microsporophylls, but each modified leaf has small, compact pollen sacks attached to their lower surface.[9] There has been documentation of the symbiotic relationship the Guamanian C. micronesica with Anatrachyntis sp., which depends on male cones (microsporangia) for oviposition and recruitment in return for pollinating the species.

The microsporangiate cones are pale fawn to pale orange-brown, narrowly ovoid, 30–50 cm long, 8–10 cm in diameter. Microsporophyll lamina are 35–45 mm long, 20–25 mm wide; fertile zone 25–35 mm long; sterile apex 7–10 mm long, not recurved, apical spine somewhat reduced, broad, sharply upturned, 2 mm long. Megasporophylls 27–33 cm long, grey- and orange-tomentose, with 2-6 ovules, lamina 45–55 mm wide, broadly ovate to elliptical, regularly dentate with 16-20 lateral spines, apical spine 8–15 mm long, lateral spines 2–6 mm long. Seeds flatten to ovoid, green becoming orange, not pruinose, 50–60 mm long, 45–50 mm in diameter; sarcotesta 3–6 mm thick.[8]

Conservation[edit]

Cycas micronesica is threatened by a combination of introduced species throughout the islands of Guam and Rota. The most notable pest is the diaspidid scale Aulacaspis yasumatsui, which was first recognized in Guam in December 2003.[10] Other threats include cycad blue butterfly (Luthrodes pandava), the longhorn beetle (Acalolepta marianarum) which causes stem damage, the alien invasive snail Satsuma mercatoria which feeds on young leaflets, and habitat loss due to the growing human population.[1] Prior to the invasion of Aulacaspis yasumatsui, it was one of the most abundant plants in Guam's forests.[11] Plant mortality was so rapid that the species was Red Listed as Endangered in 2006, only three years after the devastating invasions began.[12][13] Population counts in northwest Guam have declined from 686 individuals in early 2004 (before Aulacaspis yasumatsui reached this habitat) to 87 individuals in January 2007.[1] In 2004, Rhyzobius lophanthae was employed on Guam as a biological pest control and has lessened the population decline. However, they were ineffective on protecting cycad seedlings from Aulacaspis yasumatsui predation, as lack of seed vigor is one of the major factors contributing to C. micronesica decline.[14] without effective action against the Aulacaspis scale, it may become critically endangered. It used to have stable populations across Micronesia, with Guam having the largest. However, the Aulacaspis scale invasion caused an 87% decline in the Guam subpopulation over ten years.[15]

Threats[edit]

The Cycad Aulacaspis scale, an invasive species from Southeast Asia, poses a significant threat to Cycas micronesica, resulting in substantial plant mortality. However, it's crucial to emphasize that the current plant mortality is not solely due to this scale. The introduction of the Cycad Blue Butterfly in 2005 and the intensified damage caused by pre-existing arthropod pests are additional severe threats to the already weakened cycad population. Longhorn beetles, especially Acalolepta marianarum, are responsible for many recent plant deaths due to stem damage. Moreover, the invasive snail Satsuma mercatoria has emerged as a new and significant threat by feeding on young leaflets. This change in herbivore behavior may be a result of the compromised ability of unhealthy cycad plants to synthesize chemicals that deter herbivores. These threats collectively imperil the survival of Cycas micronesica.[15]

Gallery[edit]

  • Understory habitation
    Understory habitation
  • Pinnate leaf formation
    Pinnate leaf formation
  • Stem and palm-like structure
    Stem and palm-like structure
  • Female reproductive structures (megasporangia)
    Female reproductive structures (megasporangia)
  • Male cones (microsporangia)
    Male cones (microsporangia)
  • Fertilized megasporangia with developing seeds
    Fertilized megasporangia with developing seeds
  • Infestation by the armored scale on the male cone
    Infestation by the armored scale on the male cone
  • Developed seed
    Developed seed

See also[edit]

References[edit]

  1. ^ a b c Bösenberg, J.D. (2022). "Cycas micronesica". IUCN Red List of Threatened Species. 2022: e.T61316A68906033. doi:10.2305/IUCN.UK.2022-1.RLTS.T61316A68906033.en. Retrieved 22 August 2023.
  2. ^ Hill, K.D. (1994). Cycas micronesica. Australian Systematic Botany 7: 554-556.
  3. ^ Athens, J., & Ward, J. (2004). Holocene vegetation, savanna origins and human settlement of Guam. Records Of The Australian Museum, 15-30.
  4. ^ Sacks, Oliver. (1996). The Island of the Colour-blind. Pan Macmillan Australia: Sydney. ISBN 0-330-35887-1
  5. ^ Cox PA, Banack SA, Murch SJ, Rasmussen U, Tien G, Bidigare RR, Metcalf JS, Morrison LF, Codd GA, Bergman B (2005). "Diverse taxa of cyanobacteria produce b-N-methylamino-L-alanine, a neurotoxic amino acid". PNAS. 102 (14): 5074–5078. Bibcode:2005PNAS..102.5074C. doi:10.1073/pnas.0501526102. PMC 555964. PMID 15809446.
  6. ^ Esterhuizen M, Downing TG (2008). "β-N-methylamino-L-alanine (BMAA) in novel South African cyanobacterial isolates". Ecotoxicology and Environmental Safety. 71 (2): 309–313. doi:10.1016/j.ecoenv.2008.04.010. PMID 18538391.
  7. ^ Vogt, S., & Williams, L. (2004). Common flora & fauna of the Mariana Islands. Saipan?: S.R. Vogt & L.L. Williams.
  8. ^ a b Hill KD (1994). "The Cycas rumphii complex (Cycadaceae) in New Guinea and the western Pacific". Australian Systematic Botany. 7 (6): 543–567. doi:10.1071/sb9940543. ISSN 1446-5701.
  9. ^ Willis, K., & McElwain, J. C. (2014). The evolution of plants (2nd ed.). Oxford, United Kingdom; New York: Oxford University Press.
  10. ^ Terry, Irene; & Marler, Thomas. (2005). Paradise Lost? Tipping the scales against Guam’s Cycas micronesica. The Cycad Newsletter 28(3-4): 21-23.
  11. ^ Donnegan, J., & Pacific Northwest Research Station. (2004). Guam's forest resources, 2002 (Resource bulletin PNW ; 243). Portland, OR: U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station.
  12. ^ Marler, T.E.; Lawrence, J.H. (2012). "Demography of Cycas micronesica on Guam following introduction of the armoured scale Aulacaspis yasumatsui". Journal of Tropical Ecology. 28 (3): 233–242. doi:10.1017/S0266467412000119.
  13. ^ Marler, T.E. (2010). "Cycad mutualist offers more than pollen transport". American Journal of Botany. 97 (5): 841–845. JSTOR 20700414.
  14. ^ Marler, T.E.; Miller, R.; Moore, A. (2013). "Vertical Stratification of Predation on Aulacaspis yasumatsui Infesting Cycas micronesica Seedlings". HortScience. 48 (1): 60–62. doi:10.21273/HORTSCI.48.1.60.
  15. ^ a b "Redlist - Cycas micronesica".

External links[edit]

"Home". Guam Plant Extinction Prevention Program. Retrieved 2018-06-08.

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