| Florida strangler fig | |
|---|---|
 | |
| Florida strangler fig in Deering Park, Florida | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Rosales |
| Family: | Moraceae |
| Genus: | Ficus |
| Subgenus: | F. subg.Urostigma |
| Species: | F. aurea |
| Binomial name | |
| Ficus aurea Nutt. 1846, conserved name | |
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| Distribution map | |
| Synonyms[3] | |
Synonymy
| |
Ficus aurea, commonly known as theFlorida strangler fig (or simplystrangler fig),golden fig, orhiguerón,[4] is a tree in the familyMoraceae that is native to the U.S. state ofFlorida, the northern and westernCaribbean, southernMexico andCentral America south toPanama.[5] The specific epithetaurea was applied by English botanistThomas Nuttall who described the species in 1846.
Ficus aurea is astrangler fig. Infigs of this group, seed germination usually takes place in the canopy of ahost tree with the seedling living as anepiphyte until its roots establish contact with the ground. After that, it enlarges and strangles its host, eventually becoming a free-standing tree in its own right. Individuals may reach 30 m (100 ft) in height. Like all figs, it has an obligatemutualism withfig wasps: figs are only pollinated by fig wasps, and fig wasps can only reproduce in fig flowers.[citation needed] The tree provides habitat, food and shelter for a host of tropical lifeforms including epiphytes incloud forests andbirds,mammals,reptiles andinvertebrates.F. aurea is used intraditional medicine, forlive fencing, as anornamental and as abonsai.
Ficus aurea is a tree which may reach heights of 30 m (98 ft).[6] It ismonoecious: each tree bears functional male and female flowers.[7] The size and shape of the leaves is variable. Some plants have leaves that are usually less than 10 cm (4 in) long while others have leaves that are larger. Theshape of the leaves and of theleaf base also varies—some plants have leaves that are oblong or elliptic with a wedge-shaped to rounded base, while others have heart-shaped or ovate leaves withcordate to rounded bases.F. aurea has paired figs[5] which are green when unripe, turning yellow as they ripen.[8] They differ in size (0.6–0.8 cm [0.2–0.3 in], about 1 cm [0.4 in], or 1.0–1.2 cm [0.4–0.5 in] in diameter); figs are generallysessile, but in parts of northernMesoamerica figs are borne on short stalks known aspeduncles.[5]
With about 750 species,Ficus (Moraceae) is one of the largestangiosperm genera (David Frodin ofChelsea Physic Garden ranked it as the 31st largest genus).[9]Ficus aurea is classified in thesubgenusUrostigma (the strangler figs) and thesectionAmericana.[5] Recent molecularphylogenies have shown that subgenusUrostigma ispolyphyletic, but have strongly supported the validity of sectionAmericana as adiscrete group (although its exact relationship to sectionGaloglychia is unclear).[10]
Thomas Nuttall described the species in the second volume of his 1846 workThe North American Sylva[11] with specific epithetaurea ('golden' inLatin).[12] In 1768, Scottish botanistPhilip Miller describedFicus maxima, citingCarl Linnaeus'Hortus Cliffortianus (1738) andHans Sloane'sCatalogus plantarum quæ in insula Jamaica (1696). Sloane's illustration of the species, published in 1725, depicted it with figs borne singly, a characteristic of theFicus subgenusPharmacosycea.[13] As a member of the subgenusUrostigma,F. aurea has paired figs. However, a closer examination of Sloane's description led Cornelis Berg to conclude that the illustration depicted a member of the subgenusUrostigma (since it had other diagnostic of that subgenus), almost certainlyF. aurea, and that the illustration of singly borne figs was probablyartistic license. Berg located the plant collection upon which Sloane's illustration was based and concluded that Miller'sF. maxima was, in fact,F. aurea.[11] In his description ofF. aurea, which was based on plant material collected in Florida, Thomas Nuttall considered the possibility that his plants belonged to the species that Sloane had described, but came to the conclusion that it was a new species.[11] Under the rules ofbotanical nomenclature, the nameF. maxima has priority overF. aurea since Miller's description was published in 1768, while Nuttall's description was published in 1846.
In their 1914Flora of Jamaica,William Fawcett andAlfred Barton Rendle linked Sloane's illustration to the tree species that was then known asFicus suffocans, a name that had been assigned to it inAugust Grisebach'sFlora of the British West Indian Islands.[14] Gordon DeWolf agreed with their conclusion and used the nameF. maxima for that species in the 1960Flora of Panama.[15] Since this use has become widespread, Berg proposed that the nameFicus maxima beconserved in the way DeWolf had used it,[11] a proposal that was accepted by the nomenclatural committee.[2]
Reassigning the nameFicus maxima did not leaveF. aurea as the oldest name for this species, as German naturalistJohann Heinrich Friedrich Link had describedFicus ciliolosa in 1822. Berg concluded that the species Link described was actuallyF. aurea, and since Link's description predated Nuttall's by 24 years, priority should have been given to the nameF. ciliolosa. Since the former name was widely used and the nameF. ciliolosa had not been, Berg proposed that the nameF. aurea be conserved.[11] In response to this, the nomenclatural committee ruled that rather than conservingF. aurea, that it would be better to rejectF. ciliolosa. ConservingF. aurea would mean that precedence would be given to that name over all others. By simply rejectingF. ciliolosa, the committee left open the possibility that the nameF. aurea could be supplanted by another older name, if one were to be discovered.[2]
In 1920, American botanistPaul C. Standley described three new species based on collections from Panama and Costa Rica—Ficus tuerckheimii,F.isophlebia andF. jimenezii.[16] DeWolf concluded that they were all the same species,[15] and Berg synonymised them withF. aurea.[5] These names have been used widely for Mexican and Central American populations, and continue to be used by some authors. Berg suspected thatFicus rzedowskiana Carvajal and Cuevas-Figueroa may also belong to this species, but he had not examined the original material upon which this species was based.[5]
Berg consideredF. aurea to be a species with at least fourmorphs. "None of the morphs", he wrote, "can be related to certain habitats or altitudes."[5] Thirty years earlier, William Burger had come to a very different conclusion with respect toFicus tuerckheimii,F. isophlebia andF. jimenezii—he rejected DeWolf's synonymisation of these three species as based on incomplete evidence. Burger noted that the three taxa occupied different habitats which could be separated in terms of rainfall and elevation.[17]
Figs have an obligatemutualism withfig wasps, (Agaonidae); figs are only pollinated by these wasps, and they can only reproduce in fig flowers. Generally, each fig species depends on a single species of wasp for pollination. The wasps are similarly dependent on their fig species in order to reproduce.Ficus aurea is pollinated byPegoscapus mexicanus (Ashmead).[18]
Figs have complicatedinflorescences calledsyconia. Flowers are entirely contained within an enclosed structure. Their only connection with the outside is through a small pore calledostiole.Monoecious figs likeF. aurea have both male and female flowers within the syconium.[19] Female flowers mature first. Once mature, they produce avolatile chemical attractant.[20] Female wasps squeeze their way through the ostiole into the interior of the syconium. Inside the syconium, they pollinate the flowers, lay their eggs in some of them, and die. The eggs hatch and the larvae parasitise the flowers in which they were laid. After four to seven weeks (inF. aurea), adult wasps emerge. Males emerge first, mate with the females, and cut exit holes through the walls of the fig. The male flowers mature around the same time as the female wasps emerge. The newly emerged female wasps actively pack their bodies with pollen from the male flowers before leaving through the exit holes the males have cut and fly off to find a syconium in which to lay their eggs. Over the next one to five days, figs ripen.[20] The ripe figs are eaten by various mammals and birds whichdisperse the seeds.
Figs flower and fruit asynchronously.[7] Flowering and fruiting is staggered throughout the population. This fact is important for fig wasps—female wasps need to find a syconium in which to lay their eggs within a few days of emergence, something that would not be possible if all the trees in a population flowered and fruited at the same time. This also makes figs important food resources forfrugivores (animals that feed nearly exclusively on fruit); figs are one of the few fruit available at times of the year when fruit are scarce.
Although figs flower asynchronously as a population, in most species flowering is synchronised within an individual. Newly emerged female wasps must move away from their natal tree in order to find figs in which to lay their eggs. This is to the advantage of the fig, since it preventsself-pollination.[19] In Florida, individualF. aurea trees flower and fruit asynchronously.[7] Within-tree asynchrony in flowering is likely to raise the probability of self-pollination, but it may be an adaptation that allows the species to maintain an adequate population of wasps at low population densities or in strongly seasonal climates.[7]
| Flowering phenology inFicus aurea | ||
| Phase[20] | Description[20] | Duration inF. aurea[20] |
|---|---|---|
| A (pre-female) | Immature flowers | 2 days to >9 months |
| B (female) | Female flowers are receptive to pollination; female wasps lay eggs and pollinate flowers | 1 day to 3 weeks |
| C (interfloral) | Fig seeds and wasp larvae develop | 4 to 7 weeks |
| D (male) | Male flowers mature; wasps emerge, mate and female wasps disperse | 1 to 2 days |
| E (post-floral) | Fruits ripen | 1 to 5 days |
Floweringphenology inFicus has been characterised into five phases. In most figs, phase A is followed almost immediately by phase B. However, inF. aurea immature inflorescences can remain dormant for more than nine months.[7]
Ficus aurea is a fast-growing tree.[21] As ahemiepiphyte itgerminates in thecanopy of a host tree and begins life as anepiphyte before growing roots down to the ground.F. aurea is also astrangler fig (not all hemiepiphytic figs are stranglers)—the rootsfuse and encircle the host tree. This usually results in the death of the host, since it effectivelygirdles the tree.Palms, which lacksecondary growth, are not affected by this, but they can still be harmed by competition for light, water and nutrients.[22] FollowingHurricane Andrew in 1992,F. aurea trees regenerated fromroot suckers and standing trees.[23]
Ficus aurea ranges from Florida, across the northern Caribbean to Mexico, and south across Central America. It is present in central and southern Florida and theFlorida Keys,[24] The Bahamas, the Caicos Islands, Hispaniola, Cuba, Jamaica, the Cayman Islands,San Andrés (a Colombian possession in the western Caribbean),[5] southern Mexico,[25] Belize, Guatemala, Honduras, Nicaragua, El Salvador, Costa Rica and Panama.[26] It grows from sea level up to 1,800 m (5,500 ft)above sea level,[5] in habitats ranging fromBahamian dry forests,[27] tocloud forest in Costa Rica.[28]
Ficus aurea is found in central and southern Florida as far north asVolusia County;[29] it is one of only two native fig species in Florida.[30] The species is present in a range of south Florida ecosystems, including coastal hardwoodhammocks,cabbage palm hammocks,tropical hardwood hammocks and shrublands, temperate hardwood hammocks and shrublands[31] and along watercourses.[20] In The Bahamas,F. aurea is found intropical dry forests onNorth Andros,[32]Great Exuma[27] andBimini.[33]F. aurea occurs in 10states in Mexico, primarily in the south, but extending as far north asJalisco.[25] It is found in tropical deciduous forest, tropical semi-evergreen forest, tropical evergreen forest, cloud forest and in aquatic or subaquatic habitats.[25]
Ficus aurea is a strangler fig—it tends to establish on a host tree which it gradually encircles and "strangles", eventually taking the place of that tree in the forest canopy. While this makesF. aurea an agent in the mortality of other trees, there is little to indicate that its choice of hosts is species specific. However, indry forests onGreat Exuma in The Bahamas,F. aurea establishes exclusively onpalms, in spite of the presence of several other large trees that should provide suitable hosts. Eric Swagel and colleagues attributed this to the fact thathumus accumulates on the leaf bases of these palms and provides a relatively moistmicroclimate in a dry environment, facilitating seedling survival.[27]
Figs are sometimes considered to be potentialkeystone species in communities offruit-eating animals because of theirasynchronous fruiting patterns.[34] Nathaniel Wheelwright reports thatemerald toucanets fed on unripeF. aurea fruit at times of fruit scarcity inMonteverde, Costa Rica.[35] Wheelwright listed the species as a year-round food source for theresplendent quetzal at the same site.[36] In theFlorida Keys,F. aurea is one of five fruit species that dominate the diet fed bywhite-crowned pigeons to their nestlings.[37]F. aurea is also important in the diet of mammalian frugivores—both fruit and young leaves are consumed byblack howler monkeys in Belize.[38]
The interaction between figs andfig wasps is especially well-known (see section onreproduction, above). In addition to its pollinators (Pegoscapus mexicanus),F. aurea is exploited by a group of non-pollinatingchalcidoid wasps whose larvae develop in its figs. These includegallers,inquilines andkleptoparasites as well asparasitoids of both the pollinating and non-pollinating wasps.[39]
The invertebrates withinF. aurea syconia in southern Florida include a pollinating wasp,P. mexicanus, up to eight or more species of non-pollinating wasps, a plant-parasitic nematode transported by the pollinator, mites, and a predatory rove beetle whose adults and larvae eat fig wasps.[40]Nematodes:Schistonchus aureus (Aphelenchoididae) is a plant-parasitic nematode associated with the pollinatorPegoscapus mexicanus and syconia ofF. aurea.[41] Mites: belonging to the family Tarsonemidae (Acarina) have been recognized in the syconia ofF. aurea andF. citrifolia, but they have not been identified even to genus, and their behavior is undescribed.[40]Rove beetles:Charoxus spinifer is a rove beetle (Coleoptera: Staphylinidae) whose adults enter late-stage syconia ofF. aurea andF. citrifolia.[42] Adults eat fig wasps; larvae develop within the syconia and prey on fig wasps, then pupate in the ground.[43]
As a large tree,F. aurea can be an important host forepiphytes. In Costa Rican cloud forests, whereF. aurea is "the most conspicuous component" of intact forest,[28] trees in forest patches supported richer communities of epiphyticbryophytes, while isolated trees supported greaterlichen cover.[28]
Florida International University ecologist Suzanne Koptur reported the presence ofextrafloral nectaries onF. aurea figs in the FloridaEverglades.[44] Extrafloral nectaries are structures which producenectar but are not associated with flowers. They are usually interpreted as defensive structure and are often produced in response to attack by insectherbivores.[45] They attract insects, primarilyants, which defend the nectaries, thus protecting the plant against herbivores.[46]
Ficus aurea, amongst other relatedFicus species, has been a source of bark for preparingamate, the bark paper used forcodices in the Mesoamerican civilizations. The oldest example dates back to 75 CE and was found in ashaft tomb culture site in Huitzilapa,Jalisco inMexico.[47][48]
The fruit ofFicus aurea is edible and was used for food by theNative Americans and early settlers in Florida; it is still eaten occasionally as a backyard source of native fruit. The latex was used to make a chewing gum, and aerial roots may have been used to make lashings, arrows, bowstrings and fishing lines. The fruit was used to make a rose-coloured dye.[49]F. aurea was also used intraditional medicine in The Bahamas[50] and Florida.[49] Allison Adonizio and colleagues screenedF. aurea for anti-quorum sensing activity (as a possible means of anti-bacterial action), but found no such activity.[51]
IndividualF. aurea trees are common on dairy farms in La Cruz, Cañitas andSanta Elena in Costa Rica, since they are often spared when forest is converted topasture. In interviews, farmers identified the species as useful for fence posts,live fencing and firewood, and as a food species for wild birds and mammals.[4]
Ficus aurea is used as anornamental tree, anindoor tree and as abonsai.[8] Like other figs, it tends to invade built structures and foundations, and needs to be removed to prevent structural damage.[40] Although young trees are described as "rather ornamental",[30] older trees are considered to be difficult to maintain (because of theadventitious roots that develop off branches) and are not recommended for small areas.[8] However, it was considered a useful tree for "enviroscaping" to conserve energy in south Florida, since it is "not as aggressive as many exotic fig species," although it must be given enough space.[21]
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