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THE BIOLOGY OF PERIPLOCA SP. (LEPIDOPTERA:
COSMOPTERIGIDAE): A GALL MAKER ON ARDISIA ESCALLONIOIDES
(MYRSINACEAE)
John B. Pascarella
Department of Biology
With 180 species from 26 genera described for North
America, the cosmopterigid moths are a taxon of small moths which
are primarily leaf miners in the larval stage (Hodges 1978, Borror
et al. 1989). Other species are stem and root gall makers, seed
and flower predators, and plant material scavengers (Hodges 1978).
In this study, I describe the life-cycle of an undescribed species
of Periploca which creates fruit galls in the tropical shrub Ardisia
escallonioides (Myrsinaceae). Information is presented on the
geographic distribution and the life-cycle of the moth, including
data on oviposition, larval development, pupation, adult lifespan,
and parasitoids.
The host plant, Ardisia escallonioides Schlechtendahl
& Chamisso (Myrsinaceae) is common to dominant understory
shrub in the subtropical hammocks (=forests) of south Florida
(Alexander 1958, 1967, Olmsted et al. 1983, Molnar 1990). It also
occurs in the Bahamas, Cuba, Hispaniola, Eastern Mexico, Belize,
Guatemala, and northern Honduras, primarily in moist coastal forests
on limestone (Lundell 1966). The principal habitat of A. escallonioides
in Florida is subtropical hardwood forest on the Miami rock ridge
and the Florida Keys, although small populations are found northward
along the coast and in central Florida (Little 1978, Tomlinson
1980, Snyder et al. 1990).
The biology of A. escallonioides and Periploca sp.
was studied in two subtropical forest sites: Deering Estate and
Matheson Hammock, Dade Co., FL. Additional observations were made
at Castellow Hammock and Everglades National Park (Dade Co., FL)
and Ding Darling National Wildlife Preserve, Sanibel Island (Lee
Co., FL). Additional data on moth distribution was based on examination
of herbarium sheets of A. escallonioides for the distinctive fruit
galls. Laboratory data on pupation, adult behavior and lifespan,
and parasitoids was based on fruit galls collected from Deering
Estate (Miami, FL) in spring of 1992. Individual larvae were reared
from fruit galls in glass vials. Data on oviposition was collected
in July 1992 at Deering Estate. Various stages of flower development
(young buds, older buds, open flowers, 23 flowers of each type)
were examined using a 10-40× microscope to determine timing
of oviposition and number of eggs laid per flower. Data on gall
overwintering survival was recorded from ten marked plants (8
inflorescences on each) in 1991-1992 at Deering Estate. Data on
larval emergence from fruit galls was taken during surveys at
Deering Estate in 1991-1992 and Matheson Hammock in 1993.
Fruit galls were noted in all field sites and have
been recorded from herbarium sheets from an additional 10 counties
where the host plant occurs in Florida, from four islands in the
Bahamas, and from one collection from Mexico (Table 1). Most collections
with fruit galls occurred in March although collections in April
were also common.
Table 1. Representative list of Ardisia escallonioides
specimens with fruit galls produced by Periploca sp. Herbarium
abbreviations are the following: FTG (Fairchild Tropical Garden),
GA (University of Georgia), and MO (Missouri Botanical Garden).
Country, State
All stages of flower development were associated
with at least a single larvae. More larvae were found in older
stage flowers [young buds=30% attacked (7/23), older buds=39%
attacked (9/23), open flowers=65% attacked (15/23)]. Attacked
flowers were distinguishable by a brown oviposition scar on the
outside of the ovary. The larvae were consistently found at the
base of the central placenta where it was attached to the peduncle.
The larvae first ate the ovules inside the ovary. This was followed
by the development of a nutritive layer of gall tissue. Fruit
galls did not contain seeds. Gall formation was independent of
pollination. Both hand-pollinated and emasculated, bagged flowers
produced fruit galls in a separate plant breeding system experiment
(unpublished data).
Galled fruits were distinguishable from unattacked
fruits by their darker green color and swollen, misshapen appearance.
Fruit galls were found from 1-9 m in height on the host plant.
In flowers that were attacked in July and August in all years,
larvae left the fruit galls in approximately four-five wks after
hatching. In all flowers that were attacked later than August
(September-December), larvae overwintered inside the fruit galls
until the following summer. Although unattacked fruits ripened
in the spring months (February and March) and were dispersed by
frugivorous birds in March and April, galled fruits remained green
and did not ripen until the following summer. At Deering Estate,
3% of the overwintering fruit galls were lost from November 1991
to May 1992. At Deering Estate in 1992, 2298 moths out of 2679
(86%) left their fruit galls between June 15th and August 15th.
At Matheson Hammock in 1993, a detailed census of 120 fruit galls
from May to October found that relatively few moths left during
May, June, and July (29% total), most left during August (62%),
and the remainder left in September (9%) (Fig. 1). Larvae left
the fruit galls by boring a small tunnel. Larvae likely pupate
in the leaf litter and soil.
In the laboratory, moth larvae emerged from the fruit
galls within 4-20 d after the removal of the galls from the plant.
They consumed the entire contents of the fruit galls before leaving.
The larvae are approximately 6 mm long by 1.1 mm wide. Larvae
were active for 3-10 d before beginning pupation. Mean larval
weight ± 1 SE was 4.2±0.03 mg (range 2.0-6.9 mg, n=21),
while mean gall weight ± 1 SE was 169.0±24.0 mg (range
33.0-357.7 mg, n=21). Larval weight was not significantly correlated
with fruit gall weight (r=0.07, P=0.75, n=21). Larvae pupated
in a whitish cocoon. Pupation lasted 28 to 37 d (mean length=32.4±3.7
d, n=85 larvae).
Adult females are slightly larger (approximately
6 mm body length), have larger labial palps, and are more brightly
marked than males. Females have black and glittery gold wing markings
while males have pale, translucent wings. Adult moths in the laboratory
did not feed on a nectar solution nor on fresh flowers with nectar.
Length of adult life was short, with mean length of survival ±
1 SE, 3.06±0.33 d (range 1-10 d, n=36).
Less than 2% of larvae that reached pupation in the
laboratory were parasitized by the encyrtid wasp, Copidosoma sp.
Wasp pupation lasted approximately 20 d. In 14 parasitized larvae,
19-33 wasps (x=26.8±4.1 wasps) emerged over a 4-7 d period
(x=5.1±0.8 d). The mean number of wasps/larvae was positively
correlated with larval length (r=0.60, P<0.05, df=12). All
wasp larvae pupated successfully (100% emergence) and no parasitoids
of the encyrtids were noted.
The moth life-cycle is highly synchronized with the
flowering phenology of its host plant, Ardisia escallonioides.
A. escallonioides begins flowering in July, peaks in September
and October, and ceases flowering by December (Pascarella, 1996).
The bivoltine life-cycle permits moths to locate both early and
late flowering plants. Moths that attack later flowering plants
undergo diapause and do not emerge until the following summer,
an adaptive response given the strong seasonal flowering of the
host plant. Delayed fruit ripening of the fruit galls results
in few galls being consumed by frugivorous birds which generally
avoid green fruits (Foster, 1977).
This species of Periploca appears to be a specialist
on Ardisia escallonioides. While widespread on this plant in Florida,
the Bahamas, and Mexico, occurrence of the moth on A. escallonioides
populations elsewhere is unknown due to lack of examination of
herbarium specimens from these areas.
Funding for this research was provided by a University
of Miami Curtis Plant Sciences grant and a University of Miami
Graduate Research Support award. I was supported by a National
Science Foundation Predoctoral Research Fellowship and a University
of Miami Maytag Fellowship, and I wish to thank Metro-Dade County
Natural Areas Management for permission to work at the Dade County
Parks. Special thanks to J. B. Heppner of the University of Florida
Entomology and Nematology Insect Identification Laboratory for
identification of the cosmopterigid moth, and M. E. Schauff, U.S.D.A.,
Systematic Entomology Laboratory, Agricultural Research Service
for identification of the encyrtid wasp. This is contribution
number 516 from the University of Miami Program in Tropical Biology,
Ecology, and Evolution.
Summary
An undescribed species of cosmopterigid moth, Periploca
sp., is a specialized gall-maker on the tropical shrub, Ardisia
escallonioides (Myrsinaceae), in Florida. Eggs are laid in flowers
where a single larva induces a gall. The life-cycle is bivoltine
with a summer generation and an overwintering generation. The
overwintering larvae leave the galls the following summer, primarily
in August. Pupation takes 28 to 37 d. Adults live 2-5 d in the
laboratory. Of larvae reared in the laboratory, 1.8% were parasitized
by the encyrtid wasp, Copidosoma sp., which was polyembryonic
with an average of 27 wasps per infested larva.
References Cited
Alexander, T. R. 1958. High hammock vegetation of
the southern Florida mainland. Quarterly Journal Florida Academy
of Sciences 21: 293-298.
Alexander, T. R. 1967. A tropical hammock in the
Miami (Florida) limestone: a twenty-five year study. Ecology 48:
863-867.
Borror, D. J., C. A. Triplehorn, and N. F. Johnson.
1989. An Introduction to the Study of Insects. Saunders College
Publishing, Ft. Worth, TX.
Foster, M. S. 1977. Ecological and nutritional effects
of fruit scarcity on a tropical frugivorous bird and its fruit
source. Ecology 58: 73-85.
Hodges, R. W. 1978. The Moths of America North of
Mexico including Greenland. Fascicle 6.1 Gelechioidea Cosmopterigidae.
E. W. Classey Limited and the Wedge Entomological Research Foundation,
London, UK.
Little, E. L., Jr. 1978. Atlas of United States Trees.
Vol. 5: Florida. U.S. Forest Service Miscellaneous Publication
Number 1361. U.S. Government Printing Office, Washington, D.C.
Lundell, C. L. 1966. Myrsinaceae, pp. 137-199 in
P. C. Standley and L. O. Williams, [eds]. Flora of Guatemala.
Fieldiana:Botany 24: No.1 and 2. Chicago Natural History Museum,
Chicago, IL.
Molnar, G. 1990. Successional dynamics of a tropical
hardwood hammock on the Miami rockridge. M.Sc. dissertation, Florida
International University, Miami, FL.
Olmsted, I. C., W. B. Robertson, Jr., J. Johnson,
and O. L. Bass, Jr. 1983. The vegetation of Long Pine Key, Everglades
National Park. Everglades National Park South Florida Research
Center Report Number SFRC-83/05.
Pascarella, J. B. 1995. The effects of Hurricane
Andrew on the population dynamics and the mating system of the
tropical understory shrub Ardisia escallonioides (Myrsinaceae).
Ph.D. dissertation. University of Miami, Coral Gables, FL.
Pascarella, J. B. 1996. Pollination ecology of Ardisia
escallonioides (Myrsinaceae). Castanea, in press.
Snyder, J. R., A. Herndon, and W. B. Robertson, Jr.
1990. South Florida rockland, pp. 230-274 in R. L. Myers and J.
J. Ewel, [eds]. Ecosystems of Florida. University of Central Florida
Press, Orlando, FL.
Tomlinson, P. B. 1980. The biology of trees native
to tropical Florida. Published by the author. Petersham, MA.
Fig. 1. Temporal pattern of larval emergence from
fruit galls during summer months at Matheson Hammock, Miami, FL
(1993).
University of Miami
Coral Gables, Florida 33124-0421
County & Location
Collector & No., Herbarium
Month
Collected
USA, Florida
St. Johns-St. Augustine
Demaree 10167, MO
Jan.
USA, Florida
Volusia
Duncan 30317, GA
Oct.
USA, Florida
Brevard-Lori Wilson Park, Cocoa Beach
Poponoe 1660, FTG
Apr.
USA, Florida
Indian River-Sneeds Rd.
Tracy 6844, MO
Apr.
USA, Florida
St. Lucie-Coastal
Hammock A1A
Hansen et al. 7159, FTG
May
USA, Florida
Manatee-Palmetto
Nash 2458, MO
Aug.
USA, Florida
Highlands
Wilburt & Webster 2607, GA
Aug.
USA, Florida
Palm Beach-Delray Beach
McDaniel 9175, GA
Jun.
USA, Florida
Broward
Carter et al. S.n., GA
Mar.
USA, Florida
Dade-Old Cutler
Hammock
Correll et al. 47076, FTG
Apr.
USA, Florida
Monroe-Upper Key Largo
Stern 3005, FTG
Apr.
Bahamas
Grand Bahama,
Freeport
Austin and Curray 4584, FTG
Mar.
Bahamas
Andros
Correll & Godfrey 41322, FTG
Jan.
Bahamas
New Providence
Correll & Correll 48277, FTG
Mar.
Bahamas
Great Abaco
Correll & Meyer 44517, FTG
Mar.
Mexico
Tamaulipas-Mun. Aldama
MO
Dec.