An annotated list of the aquatic invertebrates inhabiting water impounded in the leaf axils of Florida’s native epiphytic bromeliads is provided. Of the 22 species reported, 9 are yet undescribed. Of the 13 described species, 10 are believed to be native. Five of the native species and perhaps all of the undescribed species are precinctive (“endemic”). These invertebrate animals and their bromeliad host plants are at risk of extinction due to destruction of the host plants by Metamasius callizona (Chevrolat) (Coleoptera: Dryophthoridae), an invasive weevil.
In the early 1970s, D. Fish conducted an extensive study of the aquatic invertebrate fauna of the phytotelmata in the leaf axils of native bromeliads from central Florida south to the Everglades, but not the Florida Keys. Meanwhile, J. H. Frank was conducting an intensive ecological and ethological study of the mosquito genus Wyeomyia, whose immature stages inhabit bromeliad leaf axils in southern Florida. The Ph.D. dissertation of Fish (Fish 1976) reported several species for which specialist taxonomists were unable at that time to provide species-level identifications. The two investigators collaborated on chapters of a book. Fish (1983) wrote about phytotelmata in general. Frank (1983) wrote about bromeliad phytotelmata; included was a review of the knowledge of the way of life of southern Florida’s Wyeomyia mosquitoes; included also was a catalog of aquatic organisms from bromeliad phytotelmata worldwide with bibliography; this catalog included records provided by Fish (1976).
In the late 1980s G. F. O’Meara (Florida Medical Entomology Laboratory) began studies on mosquito larvae in imported, ornamental bromeliads. Frank et al. (2004) reported on the total (not just aquatic) macro-invertebrate fauna of a small sample of native bromeliads in Sarasota County, collected in 1997 by S. Sreenivasan, an intern at the Marie Selby Botanical Gardens. Then, L. J. Hribar (Florida Keys Mosquito Control District) reported new finds of bromeliad-inhabiting aquatic invertebrates from this limited area (Wagner & Hribar 2005; Grogan & Hribar 2006; Reid & Hribar 2006).
In 1989, an invasive weevil, Metamasius callizona (Chevrolat), was detected in Broward County, destroying native Florida bromeliads. Its larvae mine the meristematic tissue and kill the plants (Frank & Thomas 1994). By 2005, its populations had spread to most southern Florida counties, it threatened the survival of 12 of the 16 species (Table 1) of native Florida bromeliads, including all those species that provide phytotelmata, and a biological control campaign had been started to attempt to limit the destruction (Frank & Cave 2005). Several native bromeliads had already been declared to be threatened or endangered, and attrition by the weevil caused 2 more to be placed on the list of endangered species (Florida Administrative Code 1998). Natural bromeliad populations suffer losses due to natural causes such as wind and breakage of tree branches, but M. callizona has increased those losses to an unsustainable level. Death of Tillandsia utriculata and T. fasciculata from natural populations was monitored in the Myakka River State Park (Sarasota County for 49 mo.), Loxahatchee National Wildlife Reserve (Palm Beach County, for 28 mo.), Highlands Hammock State Park (Highlands County for 33 mo.), and St. Sebastian River Preserve State Park (Indian River County for 17 mo.) ending in Jun 2005. The percentage deaths due to M. callizona ranged from 71% to 82%, far exceeding the deaths due to other causes (Cooper 2006).
The fate of all specialist aquatic organisms inhabiting phytotelmata in Florida’s native bromeliads may now depend upon the success of this biological control campaign. It is now urgent to catalog the invertebrates that depend upon these plants as habitat. This paper is an attempt to describe what may be lost if the weevil is not controlled. Although vertebrates in Florida may use bromeliads as food, concealment, hunting grounds, or water sources (the free water in the axils), no vertebrates depend upon bromeliads in Florida as habitat for reproduction; it is the invertebrate fauna that will be most affected.
We present an annotated list of the specialist aquatic bromeliad-inhabiting organisms in Florida. Species that seem to be occasional inhabitants are mentioned in passing. We attempt to distinguish the precinctive species (those that have been detected only in Florida, often called “endemic”, but see Frank & McCoy 1990) from species with a wider distribution. For those species with a wider distribution, we attempt to distinguish those that have been present for a long time (probably pre-Columbian) from those that may have arrived very recently as contaminants of imported, ornamental bromeliads or other imported materials. We start with the viewpoint that the ancestors of Florida’s native bromeliads arrived as wind-dispersed seed (see e.g., Luther 1993). The bromeliads established, dispersed, and began to diverge. One result of their evolution in Florida was the precinctive species Tillandsia simulata. Other results included increasing genetic diversity of Florida’s native bromeliads and the evolution of natural hybrids which may be incipient species. Once the bromeliads had colonized southern Florida, they in turn were subject to colonization by wind-blown invertebrates especially from the Greater Antilles and Mexico’s Yucatan peninsula. Then, the invertebrates began to evolve. It must not be supposed that arrival of the bromeliads or the invertebrates was a single event; instead, there probably is continual natural arrival (immigration) of propagules (Luther 1993), but it has recently been complicated by inadvertent effects of international trade (human activities) in allowing the arrival of additional invertebrate species as contaminants of imported bromeliads.
When a species known only from Brazil has been detected recently in Florida, we suspect that it arrived as a contaminant of imported plants. When a species known from the Greater Antilles has been known in Florida for decades, we suspect that it arrived in pre-Columbian times.
Specialist Macro-invertebrates Detected in Bromeliad Phytotelmata in Florida
Turbellaria: Family, genus and species unidentified, of Fish, 1976
Annelida: Oligochaeta: Tubificidae, Naidinae
Dero (Aulophorus) superterrenus Michaelsen, 1912
This aquatic annelid was reported as unidentified by Fish (1976), but was abundant in epiphytic bromeliads in some localities. Specimens collected from T. utriculata at Vero Beach sent by Frank to J. K. Hiltunen (Great Lakes Laboratory, Ann Arbor, MI) were identified as reported by Frank & Lounibos (1987). The species was originally described from epiphytic bromeliads in Costa Rica by Michaelsen (1912), an early discovery by Picado (1913). It has a wide distribution in the Neotropics. Lopez et al. (2005) in Brazil found that it is attracted to frogs visiting the bromeliads, and crawls onto their skin and uses frogs for dispersal.
Arthropoda: Crustacea: Ostracoda: Cytheridae
Metacypris Brady & Robertson
Metacypris maracaoensis Tressler, 1941
This ostracod was initially reported from epiphytic bromeliads in Puerto Rico, and was later found in epiphytic bromeliads in Collier County, Florida (Tressler 1956). It was collected by Fish, identified by C. W. Hart (Smithsonian Institution, Washington, D.C.) reported by Fish (1976); it was abundant in leaf axils of T. fasciculata in Everglades National Park, and less common in other bromeliads. Lopez et al. (2005) found that Elpidium, another ostracod genus, used phoresy on frogs for transport from bromeliad to bromeliad in Brazil, like Dero worms.
Arthropoda: Crustacea: Ostracoda
Arthropoda: Crustacea: Copepoda: Cyclopidae
Paracyclops bromeliacola Karaytug & Boxshall, 1998
This copepod, originally described from bromeliads in Brazil by Karaytug & Boxshall (1998), was found in a bromeliad in the Florida Keys by Reid & Hribar (2006) who suggested that it might have arrived in Florida on ornamental bromeliads imported from Brazil. They did not identify the bromeliad in which it was collected. They did not identify the bromeliads from which 2 other cyclopids were collected in the Florida Keys: Bryocyclops muscicola Menzel, and Paracyclops chiltoni (Thomson). These last 2 species are not believed to be bromeliad specialists.
Arthropoda: Crustacea: Copepoda: Phyllognathopodidae
Although Phyllognathopus vigueiri (Maupas) has been found in bromeliad phytotelmata in several countries (Frank 1983); it seems to be a generalist, not a bromeliad specialist. Its finding in unnamed bromeliads in the Florida Keys was predictable given that it had been found in other non-phytotelm habitats elsewhere in Florida (Reid & Hribar 2006).
Arthropoda: Arachnida: Acari: Histiostomatidae (formerly Anoetidae)
Anoetus sp. of Fish, 1976
Initial identification was made by H. L. Cromroy (University of Florida) as reported by Fish (1976). To the best of our knowledge the species has not yet been described. If it really belongs to the genus Anoetus, it may feed on bacteria as do other species in the genus.
Arthropoda: Insecta: Diptera: Sciaridae
Corynoptera sp. of Fish, 1976
Specimens collected by Fish were identified by W. A. Steffan (Bishop Museum, Honolulu, HI) as reported by Fish (1976). The aquatic larvae are presumed to feed on fungi growing on decaying leaf litter. To the best of our knowledge the species has not yet been described.
Arthropoda: Insecta: Diptera: Psychodidae
Alepia symmetrica Wagner & Hribar, 2005
Fish (1976) reported that aquatic larvae of a psychodid were abundant in epiphytic bromeliads in some localities in southern Florida. The tentative identification supplied by F. C. Thompson (USDA Systematic Entomology Laboratory) was as an unidentified species of Neurosystasis. However, specimens apparently of the same species collected in 1997-2001 and supplied to a specialist taxonomist were identified as a species of Alepia (Frank et al. 2004). The name Alepia symmetrica Wagner & Hribar was based on specimens from the Florida Keys. For the present, we assume that this is the same species that occurs in bromeliads elsewhere in Florida, and that it has been present in Florida for a long time as an inhabitant of leaf axils of native epiphytic bromeliads. It has adapted to imported, ornamental bromeliads in urban areas. For lack of evidence, we here treat it as a precinctive species because we have no way of knowing whether it occurs elsewhere. We presume that the larvae feed on submerged leaf litter.
Arthropoda: Insecta: Diptera: Culicidae
Wyeomyia mitchellii (Theobald), 1905
W. vanduzeei Dyar & Knab, 1906
Wyeomyia mitchellii was originally described from Jamaica, and is known also from other islands of the Greater Antilles, eastern Mexico, and Florida. Wyeomyia vanduzeei was originally described from Florida, and is known also from Cuba, the Cayman Islands, and Jamaica. Both species are considered native to Florida. Fish (1976) reported both species. Adults and larvae may be identified by the key by Darsie & Morris (2003).
Adults of both species are active during daylight hours (Frank 1983; Frank et al. 1985). Of the two, W. mitchellii is more restricted to shaded habitats (Frank & O’Meara 1985). Females of both species use color vision to detect bromeliads in which to oviposit, although their color preferences differ slightly (Frank 1985, 1986). They hover over leaf axils while ovipositing, and eggs of W. vanduzeei are made buoyant by a remarkable sculpted wax-like coating (Frank et al. 1981). Their typical nursery plant is T. utriculata (Frank & Curtis 1981a), but they also will develop in other native water-impounding Tillandsia spp. (Fish 1976) and in the insectivorous bromeliad Catopsis berteroniana (Frank & O’Meara 1984). Larvae filter-feed on small particles in a nutrient-poor environment which is enriched by throughfall from tree canopies above. They compete intra- and inter-specifically for food, and have evolved a remarkable ability to survive long periods of starvation (Frank 1983). Larvae will not develop in less time than about 2 weeks--attempts to provide them with a rich diet to hasten their development in the laboratory may prove fatal to them (Frank 1983).
Both of these Wyeomyia mosquitoes have adapted to the habitat provided by imported, ornamental bromeliads that usually are cultivated terrestrially in urban habitats in southern Florida (Frank et al. 1988). They are sometimes present in greenhouses and even outdoors in northern Florida where these plants are grown beyond the northern limit of native, water-impounding bromeliads.
Culex (Micraedes) biscaynensis Zavortink & O’Meara, 1999
This species was discovered in imported, ornamental bromeliads in Dade County and also was found in T. utriculata and T. fasciculata (O’Meara & Evans 1997). It was described as a new species (Zavortink & O’Meara 1999) on the grounds that specimens could not be matched to any known mosquito species despite resemblance to a species of the subgenus Micraedes known from the Bahamas, Hispaniola, Puerto Rico, and the U.S. Virgin Islands. One interpretation is that it could be a species that evolved in isolation in southern Florida, having the same common ancestor as the abovementioned Micraedes. Another could be that it is a species that arrived as a contaminant of imported, ornamental bromeliads, and that its true origin remains to be discovered. For lack of other information, we consider it as a species precinctive to Florida.
Immature stages of mosquito species sometimes occur in bromeliads. Toxorhynchites rutilus (Coquillett) is a treehole specialist but its predacious larvae are sometimes found in Tillandsia utriculata (Frank et al. 1984) and imported, ornamental bromeliads (Frank et al. 1988). Aedes aegypti (L.) and Culex quinquefasciatus Say are not bromeliad specialists, but they sometimes colonize imported, ornamental bromeliads, especially those having the impounded water accidentally enriched by lawn grass clippings (Frank et al. 1988). Aedes bahamensis Berlin was detected in imported, ornamental bromeliads in southern Florida but it was not abundant in such habitat, and is not a bromeliad specialist (O’Meara et al. 1995). After the Asian species Aedes albopictus (Skuse) was detected in Florida, it began to displace A. aegypti in water-filled containers where A. aegypti larvae could previously be found. In places in northern Florida where imported, ornamental bromeliads are cultivated, A. albopictus larvae usurped the phytotelmata provided by those bromeliads to the extent that it was occupied by mosquito larvae at all (O’Meara et al. 1993). In southern Florida, inroad made by A. albopictus was much more limited and it represented just a small proportion of the mosquito larvae in ornamental bromeliads--the vast majority being Wyeomyia (O’Meara et al. 1993). Lounibos et al. (2003) concluded that competition with bromeliad-specialist Wyeomyia was the reason for the low numbers of A. albopictus in imported, ornamental bromeliads in southern Florida.
Arthropoda: Insecta: Diptera: Ceratopogonidae
F. (s. str.) seminole Wirth, 1976F. (Warmkea) fishi Wirth & Soria, 1979Forcipomyia (Phytohelea) bromelicola (Lutz) 1914
The first 2 species of midge were reported as unnamed by Fish (1976). Wirth (1976) described F. seminole from adult specimens collected at Vero Beach. Wirth & de Soria (1979) described F. fishi from specimens collected in T. utriculata in Brevard, Indian River, and Monroe counties. There is no indication that either of these species occurs outside Florida. The detection of F. bromelicola in the Florida Keys results from contamination of imported bromeliads (Grogan & Hribar 2006). In addition to these species, Forcipomyia (Phytohelea) oligarthra Saunders was reported from pineapple leaf axils in Highlands County, Florida, by de Meillon & Wirth (1979). This species is known from terrestrial bromeliads (Ananas and Bromelia) in several countries, but apparently not from epiphytic bromeliads, so it cannot be considered native to Florida where there are no native terrestrial bromeliads.
Arthropoda: Insecta: Diptera: Chirononomidae: Tanypodinae
Monopelopia tillandsia Beck & Beck, 1966
Monopelopia caraguata Mendes, Marcondes & de Pinho, 2003.
Monopelopia tillandsia has not yet been reported outside Florida and is considered a precinctive species. The predatory, orange-colored larvae were recorded from epiphytic Tillandsia spp. by Beck & Beck (1966), and by Fish (1976). It was seen in Tillandsia utriculata at Vero Beach and reported by Frank (1983). Monopelopia caraguata, originally described from Brazil by Mendes et al. (2003), and discovered in the Everglades by R. Jacobsen (Epler 2007), seems to be a new discovery. Because we do not know how long it has been present in Florida, we treat it as a recent arrival.
Arthropoda: Insecta: Diptera: Chirononomidae: Orthocladiinae
Metriocnemus van der Wulp
Metriocnemus sp. A of Epler, 2001
This species was reported from Florida by Beck & Beck (1966) and then by Fish (1976) under the name Metriocnemus abdominoflavatus Picado, but Epler (2001) stated that was an incorrect identification. Larvae may be abundant, do not build cases and are thought to feed on debris.
Genus H of Epler, 2001
A species of this unknown genus was reported only from bromeliads in Highlands County, Florida by Epler (2001).
Arthropoda: Insecta: Diptera: Chirononomidae: Chironominae
Tanytarsus bromelicola Cranston, 2007
Although described from Puerto Rico, from Guzmania berteroniana (Schultes f.) Mez bromeliads, this species was also reported from Indian River County, Florida from Tillandsia sp. (Cranston 2007). Almost certainly it is the unidentified tanytarsine reported by Fish (1976), who found it to be the most abundant chironomid in bromeliads. Larvae of this species, with red hemolymph, are restricted in Florida to T. utriculata where they form transportable cases and feed on microorganisms (Fish 1976).
Epler (2001) reported the finding of a larva of Dicrotendipes leucoscelis (Townes) in a Florida bromeliad, but this species is widespread in the eastern USA and is not a bromeliad specialist.
Arthropoda: Insecta: Diptera: Syrphidae
Meromacrus sp. of Fish, 1976
Fish (1976) reported an unidentified species of this genus from bromeliad phytotelmata in Florida. A few larvae probably of the same genus were noted by Frank in T. utriculata at Vero Beach, and he reported Fish’s observation (Frank 1983). F. C. Thompson (USDA, Systematic Entomology Laboratory, Washington, DC) is preparing a description of this species using specimens collected by Fish.
Arthropoda: Insecta: Diptera: Periscelididae
Stenomicra Coquillett (formerly in Aulacigastridae)
Stenomicra sp. of Fish, 1976
Fish (1976) reported predatory aquatic fly larvae identified as Stenomicra by C. W. Sabrosky (USDA Systematic Entomology Laboratory, Washington, D.C.). Larvae are dorso-ventrally flattened, have forked “tails” and are pale, and were reared to maturity on a diet of Wyeomyia larvae. This species has not yet been described.
Arthropoda: Insecta: Diptera: Muscidae
Neodexiopsis sp. of Fish, 1976
Specimens collected by Fish were identified by H. C. Huckett (Cornell University) and reported by Fish (1976). Larvae are cylindrical, pale, predatory, and were reared to maturity on a diet of Wyeomyia larvae. This species has not yet been described.
That many of the invertebrates discussed here exist in no habitat other than bromeliads is supported by the work of Picado (1913). Picado (1913, pp. 264-274) reviewed data of earlier authors as well as his own to argue that many bromeliad-inhabiting invertebrate species are restricted to bromeliads. Frank & Curtis (1981b) reviewed published collection records for 241 mosquito species whose larvae had been reported from bromeliads in the Americas south of the U.S.A., revealing that many had been found only in bromeliad phytotelmata. Some had been collected also in water-impounding leaf axils of other plants; conversely, some had been found mainly in axils of other plants, rarely in bromeliads. Corbet (1983) reviewed the phytotelma-inhabiting Odonata, distinguishing specialists from generalists and showing that some species develop only in bromeliads. These data support the existence of a specialist bromeliad-inhabiting fauna.
Florida law defines the conservation status of Florida’s native biota without regard to extralimital distributions. Seven of the bromeliad species attacked by M. callizona are listed as endangered (two because of attack by M. callizona) and three more as threatened under Florida law (Florida Administrative Code 1998). The only precinctive species among the species under attack, T. simulata, has no protected status (Table 1). None of the specialist invertebrates inhabiting these bromeliads is protected under Florida law. However, protection under Florida law provides no guarantee of funding to achieve protection--it just makes permits necessary for biologists or anyone else to collect or possess them.
U.S. Federal law, under the Endangered Species Act, operates differently. Purportedly, it pays no attention to species that may be at risk in the U.S. while having a large population outside the U.S. It concentrates on species that are precinctive in some part of the USA. Thus, we might expect that T. simulata (and the 5 invertebrates listed as precinctive in Table 2) would be eligible for protection under Federal law. The U.S. Fish and Wildlife Service has not yet accorded them protected status.
Under the Endangered Species Act, funding is available for protection of Florida populations (named as subspecies) of species that have populations elsewhere, even though these extralimital populations may be widespread and thriving. Thus, Florida populations of Felis concolor L. (cougar), Trichechus manatus L. (West Indian manatee), and Heraclides aristodemus Esper (dusky swallowtail) have been given the names of Felis concolor coryi (Bangs) (Florida panther), Trichechus manatus latirostris (Harlan) (Florida manatee), and Heraclides aristodemus ponceanus (Schaus) (Schaus swallowtail). These subspecies have been declared under the law to have protection, and are even called “endangered species.” None of the bromeliads listed in Table 1 or invertebrates listed in Table 2 has had Florida subspecies named; we might argue that this is so because the taxonomists involved have been so stretched to provide species-level identification that they have not had time to provide a finer-meshed classification.
Losses being inflicted by Metamasius callizona on Florida bromeliad populations also affect their aquatic invertebrate fauna. Twenty one native species, consisting of 12 bromeliads and at least 9 (perhaps 19) invertebrates are at risk of extinction in Florida and in the U.S.A. At least 6 of them (1 bromeliad and 5 invertebrates) seem to be precinctive species.
The most important task with the aquatic invertebrates is to get adult specimens into the hands of expert taxonomists who will identify or describe them. This task has not changed since the 1970s. It requires collecting living specimens of the juvenile aquatic organisms and rearing them to the adult stage. The task is now more difficult than it was in the 1970s because of loss of bromeliad populations and because the community of expert taxonomists is reduced by retirements and deaths.
Readers are requested not to send specimens to the authors for identification. Instead, please use the cited works to make your own identifications, and/or contact expert taxonomists. Conceivably, by making your chosen taxonomist aware of this publication (showing the historical background) you may hasten the identification process. If Florida authorities list them as endangered and require permits for their collection, this will only make more difficult the task of description and study. The best way to protect the bromeliad-associated invertebrates is to control M. callizona.
This paper documents, as far as is now possible, the identity of the aquatic invertebrates in native Florida bromeliads in order to highlight the threat caused by M. callizona. It does not include the geographic distributional information or much of the host-plant information or abundance data provided by Fish (1976). Frank & Thomas (2001) include an extensive bibliography of aquatic organisms in bromeliad phytotelmata worldwide.
We thank all the taxonomists mentioned in these pages; without their efforts there would be nothing to report. We thank the Florida Council of Bromeliad Societies for current support of technicians in Honduras who are collecting and rearing material of the biological control agent, and the South Florida Water Management District for current support of a graduate student working on the project; without that support, the biological control program against the weevil would have been terminated. We thank Tim Andrus (Tallahassee, FL) and Dennis Giardina (Naples, FL) for accompanying J. H. Frank on 2 exploratory trips to Guatemala in search of additional potential biological control agents for use against M. callizona when there were no grant funds to pay for their time or expenses. Julieta Brambila kindly prepared the Resumen. Cal Welbourn and Gary Steck kindly reviewed a draft manuscript.
Florida native bromeliads, their abundance and status under Florida law, susceptibility to attack by M. callizona, and whether they provide phytotelmata.
Aquatic bromeliad-inhabiting specialists; (A: adventive, recent arrival, perhaps as a contaminant, C: probably a pre-columbian arrival, so considered native, P: precinctive to florida; U: unidentified/undescribed).