RED IMPORTED FIRE ANTS (HYMENOPTERA: FORMICIDAE) AT GOPHER

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Wetterer & Moore: Fire Ants at Gopher Tortoise Burrows 349
RED IMPORTED FIRE ANTS (HYMENOPTERA: FORMICIDAE)
AT GOPHER TORTOISE (TESTUDINES: TESTUDINIDAE) BURROWS
JAMES K. WETTERER AND JON A. MOORE
Wilkes Honors College, Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL 33458
ABSTRACT
The gopher tortoise, Gopherus polyphemus Daudin, is endemic to the southeastern US,
where its populations are declining primarily due to habitat destruction. Tortoises are
preyed upon by many species, including the red imported fire ant, Solenopsis invicta Buren,
a destructive exotic species now common throughout the tortoises’ entire range. We surveyed
ants using tuna bait at 154 G. polyphemus burrows in a greenway reserve established to pro-
tect the tortoises in a residential area of southeast Florida. We found S. invicta present, typ-
ically recruiting to the bait in very high numbers, on the aprons of 33% of the tortoise
burrows. Solenopsis invicta occurred significantly more often at burrows within 30 m of the
greenway’s outer edge than at burrows in more interior parts of the greenway (57% versus
16%). Among the interior burrows, S. invicta occurred significantly more often at burrows di-
rectly on two narrow strips of disturbed habitat, along an old fence line and an old pipeline,
than at burrows not on these two strips (46% versus 12%). The greenway interior appears to
offer tortoises and other species some refuge from S. invicta. However, the long thin design
typical of greenways, the inclusion of walking paths through the greenways, and the policies
of prescribed burning and reduction mowing used to maintain open habitat for the tortoises
all may increase the tortoises’ exposure to S. invicta. Solenopsis invicta is also a grave threat
to other native species in these reserves, including the many animals that obligately live in-
side gopher tortoise burrows.
Key Words: edge effect, exotic species, Florida, Gopherus, greenway, Solenopsis invicta.
RESUMEN
La especia tortuga gopher, Gopherus polyphemus Daudin, es endémica al sudeste de los
EE.UU., donde sus poblaciones disminuyen principalmente debido a la destrucción de habi-
tat. Las tortugas son atacadas por muchas especies, inclusive la hormiga roja de fuego im-
portada, la Solenopsis invicta Buren, una especie exótica destructiva ahora común a toda la
región geográfica de las tortugas. Estudiamos las hormigas que atraemos con cebo de atún
en 154 madrigueras de la G. polyphemus en una reserva ecológica que se estableció para pro-
teger las tortugas en un área residencial del sudeste de la Florida. Encontramos a la S. in-
victa presente, alistanda típicamente al cebo en números muy altos, en los delantales de 33%
de las madrigueras de las tortugas. La presencia de la S. invicta ocurrió apreciablemente
más a menudo en madrigueras dentro de un parámetro de 30 m de la orilla exterior de la re-
serva que en las madrigueras en partes más interiores de la reserva (57% contra 16%). Entre
las madrigueras interiores, la S. invicta ocurrió apreciablemente más a menudo en madri-
gueras directamente en dos tiras estrechas del habitat perturbado, por una línea vieja de la
cerca y una tubería vieja, que en las madrigueras que no en estaban en estas dos tiras (46%
contra 12%). El interior de la reserva ecológica aparece ofrecer las tortugas y otras animales
algún refugio de S. invicta. El largo y estrecho diseño típico de las reservas ecológicas, la in-
clusión de senderos caminantes en las reservas ecológicas, y por la costumbre de incendios
prescritos y la reducción por cortes utilizados para mantener el habitat abierto para las tor-
tugas, todo ello puede aumentar la exposición de las tortugas a la S. invicta. La S. invicta es
también una amenaza grave a otras especies nativas en estas reservas, inclusive los muchos
animales que se ven obligados a vivir en las madrigueras de las tortugas.
Translation provided by the authors.
Gopher tortoises, Gopherus polyphemus Dau- most of the tortoise’s preferred upland habitat
din, are endemic to the coastal plains of the has been converted to, for example, citrus or-
southeastern United States (Diemer 1992) and chards, housing developments, and phosphate
populations are declining through most of their mines (Diemer 1992). The gopher tortoise is now
range, primarily due to habitat destruction protected in Florida as a “species of special con-
(Diemer 1986). The tortoises’ decline has been cern” (Diemer 1992; Florida Game & Fresh Water
particularly great in southeastern Florida, where Fish Commission 1994).
350 Florida Entomologist 88(4) December 2005
Gopher tortoises prefer habitats with sandy tile species in the southeastern US (Mount 1981).
soils for burrows, herbaceous plants for food, and Montgomery (1996) observed six cases of S. in-
open sunny spots for nesting and basking (Di- victa attacking adult three-toed box turtles (Ter-
emer 1992). Fire is a normal element in gopher rapene carolina triunguis (Agassiz)) in Texas,
tortoise habitat, and when natural fires are sup- with only one of the turtles surviving due to hu-
pressed, habitats may become overgrown. To man intervention. “It seems that the box turtle’s
maintain the open spaces necessary for herba- defensive reaction is to withdraw the plastron,
ceous vegetation and tortoise nesting and basking which cannot keep the ants out completely even
sites, land managers often use prescribed burning when tightly closed. This reaction also renders
or reduction mowing (Wade & Lunsford 1989; the turtle immobile, which enables the ants to
Main & Tanner 1999). swarm over it, seeking out small openings be-
Female tortoises lay clutches of 3-15 eggs, usu- tween the plastron and the carapace. The turtle
ally in the sand apron in front of their burrow or in must eventually relax the plastron, which allows
another nearby sunny spot (typically 16-67 cm more ants to gain further access to its body.”
from the burrow entrance; Butler and Hull 1996). Montgomery (1996) concluded, “it would be diffi-
Many predators attack gopher tortoise nests, in- cult to estimate just how much effect the ants
cluding raccoons, foxes, skunks, armadillos, and alone are having. But my observations lead me to
snakes (Douglass & Winegarner 1977; Diemer believe that fire ants pose a serious threat to
1992). Nest predation is often very high (Alford three-toed box turtles.”
1980). Landers et al. (1980) found that mammalian In addition to S. invicta, two other ant species
predators destroyed most gopher tortoise nests found in the gopher tortoises’ range also are
(87% within the first few weeks after laying) and known to attack vertebrates and may pose a
the few surviving hatchlings were often attacked threat to gopher tortoises: Solenopsis geminata
and killed by the red imported fire ant, Solenopsis (Fab.) and Wasmannia auropunctata (Roger). Al-
invicta Buren. Epperson & Heise (2003) found that though not generally as virulent as its congener
S. invicta predation accounted for 27% of post- S. invicta, S. geminata is also known to attack the
hatching mortality of gopher tortoise hatchlings. hatchlings of birds and reptiles (e.g., Stoddard
Solenopsis invicta is probably the most de- 1931; Travis 1941; Mrazek 1974). Where W. auro-
structive exotic ant species in the southeastern punctata occurs at high densities, it also can have
US, negatively impacting both invertebrates and a great impact on vertebrates. For example, in
vertebrates (Wojcik 1994; Porter & Savignano Gabon, W. auropunctata has been implicated in
1990). This invasive species arrived in Alabama blinding house cats (Felis catus L.) and native
by ship from South America and has spread wildlife, including elephants (Loxodonta africana
across the southeast US from Texas to North (Blumenbach)) (Wetterer et al. 1999). In the So-
Carolina, now occupying the entire range of the lomon Islands, locals reported that W. auropunc-
gopher tortoise. tata commonly stings the eyes of dogs that even-
Solenopsis invicta is a well-known predator on tually become blind, and attacks hatchlings of the
bird hatchlings, particularly ground-nesting spe- ground-nesting Melanesian Scrubfowl (Megapo-
cies (e.g., see Ridlehuber 1982; Sikes & Arnold dius eremita Hartlaub) (Wetterer 1997).
1986; Steigman 1993; Drees 1994; Lockley 1995; The present study was motivated, in part, by
Powell 1995; Dickinson 1995; Giuliano et al 1996; the discovery in a local greenway reserve of a
Mueller et al. 1999; Kopachena et al. 2000; Florida box turtle (Terrapene carolina bauri Tay-
H. Smith, pers. comm.). Solenopsis invicta also lor) being attacked by S. invicta (M. Floyd, pers.
attacks reptile hatchlings. Cintra (1985) found comm.). To evaluate the potential threat of S. in-
that S. invicta commonly attacked and killed victa to gopher tortoises in the reserve, we sur-
hatchling caiman (Caiman yacare (Daudin)). veyed ants at gopher tortoise burrows in the
Love (1997) noted records of S. invicta attacking greenway.
captive tortoises and hatching turtles and alliga-
tors. Allen et al. (1997) found that hatchling MATERIALS AND METHODS
American alligators (Alligator mississippiensis
(Daudin)) stung by fire ants showed decreased Study Area
weight gain and increased mortality. Reagan et
al. (2000) found that S. invicta in alligator nests Our study site was one section (“Range VIa”) of
had a significant negative impact on hatching a greenway reserve set up through the Abacoa
success. Solenopsis invicta also appears to be an residential development in Jupiter, Florida
important threat to hatching sea turtles (Wilmers (26.90°N, 80.11°W), to preserve gopher tortoise
et al. 1996; Moulis 1996; Allen et al. 1998, 2001; habitat. The entire Abacoa greenway system en-
Krahe et al. 2003; Wetterer & Wood 2005). compasses roughly 10% of the development’s land
Solenopsis invicta appears to be an important area. Our study segment included a 9.16-ha
threat to some adult reptiles as well, and is con- wooded range and an adjacent sunken water re-
sidered important in the decline of numerous rep- tention basin (Fig. 1). A path encircles the range
Wetterer & Moore: Fire Ants at Gopher Tortoise Burrows 351
Figure 1. Aerial photograph of "Range VIa" in the Abacoa greenway, Jupiter, Florida, a wooded range bounded
in the north by Frederick Small Road and on other sides by a sunken water catchment basin. An old fence line and
a recent pipeline cross the northern and eastern parts of the range. The black bar equals approximately 30 m.
and two linear areas of disturbance cross through growing in patches. The path around the outer
the northern and eastern portions of the range; edge of the wooded range is primarily covered
one is an old (>6 years-old) cleared cattle fence with bahiagrass (Paspalum notatum Flueggé)
line (fence removed) and the other is a recently that is mowed about every two to three weeks.
(<3 years-old) dug pipeline (Fig. 1). A chain-link We surveyed ants at gopher tortoise burrows
fence, separating the reserve from Frederick on 26 February, 14 March, and 16 April 2002
Small Road, bounds the north side of the range. (sampling ~1/3 of the burrows on each day) using
The range is bounded on the other three sides by a folded index card with ~1 g of canned water-
the water catchment basin with channels for di- packed tuna inside placed within 0.2 m of the bur-
recting and holding rainwater runoff from storms. row entrance between 1300 and 1500 h. We sur-
Except for the channels, the basin is dry through veyed ants using tuna bait to assess ant species
most of the year. A chain-link fence separates the present at the burrows that recruit heavily to rich
catchment basin from Central Road to the east animal protein resources. We returned 2 h (±10
and several baseball fields to the south and west. min) later and collected the cards, putting each in
The relatively undisturbed portions of the a separate zip-lock bag. We found that two h was
range consist of typical flatwood scrub (Myers and enough time to allow significant recruitment, but
Ewel 1990) with a sparse canopy of mature slash not complete bait removal. After killing the col-
pines (Pinus elliottii Engelman), an understory of lected ants in a freezer, we counted them, then
saw palmetto (Serenoa repens (Bartram)) thickets preserved them in alcohol for identification. Ste-
and scrubby oaks (Quercus spp.), and open spaces fan Cover (Museum of Comparative Zoology) and
dominated by wiregrass (Aristida beyrichiana Mark Deyrup (Archbold Biological Station) iden-
Trin. & Rupr.), with lesser amounts of runner oak tified the ants.
(Quercus minima Small) and deer moss lichens As of 16 April 2002, there were 85 marked go-
(Cladina spp. and Cladonia spp.). The old fence pher tortoises and 164 marked burrows within
line is dominated by bunches of wiregrass and our study site. This density of 9.3 tortoises/ha is
chalky bluestem (Andropogon virginicus L.) with extremely high, e.g., it is more than three times
small stands of young slash pine saplings and higher than the highest mean density (2.7/ha) at
gallberry (Ilex glabra (L.)). The pipeline area is Kennedy Space Center in east-central Florida
largely open sand with low grasses and herbs (Breininger et al. 1994). This high density is due,
352 Florida Entomologist 88(4) December 2005
in part, to people releasing gopher tortoises found 15.0; P < 0.001). We found one or more species of
elsewhere into the greenway (Diemer 1986). exotic ant other than S. invicta equally often at
From a map of burrow locations in the study edge burrows (8/63 = 13%) as at interior burrows
area, we calculated the distance to the nearest (18/91 = 20%; χ2 = 1.3; ns). We found only one spe-
edge of the wooded range for each burrow. We cies significantly less often at edge burrows than
classified burrows less than 30 m from the perim- at interior burrows, the native Crematogaster at-
eter of the wooded range as “edge” burrows; all kinsoni Wheeler (χ2 = 6.4; P < 0.05); several ant
others we classified as “interior” burrows. species showed a strong trend in this direction,
but we lacked sufficient sample size to demon-
RESULTS strate statistical significance.
Among the 91 interior burrows, we found S. in-
We surveyed ants at 154 of the 164 marked go- victa significantly more often at burrows directly
pher tortoise burrows; we excluded ten burrows on the narrow disturbed strips along the old fence
because other animals removed the bait cards. All line and pipeline (6/13 = 46%) than at interior
surveyed burrows had at least one ant present burrows not on these strips (9/78 = 12%; χ2 = 9.7;
(range = 1-637 ants; median = 62 ants). We found P < 0.005). Sample size for edge burrow on and off
19 ant species (1-3 species per bait; Table 1); the these disturbed strips was too small for statistical
most common was S. invicta, which occurred at 51 comparison.
burrows (33%; Table 1). The only other ant found
that may pose a threat to tortoises was the little DISCUSSION
fire ant, Wasmannia auropunctata, which oc-
curred at four burrows (3%). Solenopsis invicta We found S. invicta present at most gopher tor-
tended to recruit more workers to baits they occu- toise burrows around the outer perimeter of the
pied (median = 160 ants) than did other ant spe- greenway reserve, but at few burrows in the inte-
cies (median = 40 ants). rior portions of the greenway. Conversely, native
We found S. invicta significantly more often at ants were significantly less common on the outer
edge burrows (36/63 = 57%) than at interior bur- perimeter than in the interior of the greenway. We
rows (15/91 = 16%; χ2 = 27.8; P < 0.001). In con- also found that S. invicta was present more often
trast, we found one or more species of native ant at burrows on two disturbed strips through the
significantly less often at edge burrows (23/63 = interior of the greenway than at burrows in other
37%) than at interior burrows (62/91 = 68%; χ2 = parts of the greenway interior. These corridors of
TABLE 1. ANTS ON TUNA BAITS AT TORTOISE BURROWS ON THE GREENWAY EDGE (n = 63) AND THE GREENWAY INTERIOR
(n = 91). ‡ = POTENTIAL THREAT TO GOPHER TORTOISES.
Occurrence at burrows
Exotic ant species # edge # interior
‡Solenopsis invicta Buren 36 15
Pheidole moerens Wheeler 3 10
Technomyrmex albipes (Smith) 1 4
‡Wasmannia auropunctata (Roger) 1 3
Brachymyrmex obscurior Forel 1 1
Cardiocondyla emeryi Forel 1 1
Tapinoma melanocephalum (Fabr.) 1 1
Paratrechina longicornis (Latr.) 0 1
Native ant species
Pheidole floridana Emery 13 32
Crematogaster atkinsoni Wheeler 4 21
Crematogaster ashmeadi Mayr 0 6
Forelius pruinosus (Roger) 3 3
Pheidole dentata Mayr 3 3
Dorymyrmex bureni (Trager) 3 2
Pheidole morrisii Forel 2 2
Aphaenogaster miamiana Wheeler 1 1
Temnothorax pergandei (Emery) 1 1
Aphaenogaster flemingi Smith 1 0
Dorymyrmex bossutus (Trager) 0 1
Wetterer & Moore: Fire Ants at Gopher Tortoise Burrows 353
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Pardo-Locarno et al.: White Grub Complex in Agroecological Systems 355
STRUCTURE AND COMPOSITION OF THE WHITE GRUB COMPLEX
(COLEOPTERA: SCARABAEIDAE* ) IN AGROECOLOGICAL SYSTEMS
OF NORTHERN CAUCA, COLOMBIA
LUIS CARLOS PARDO-LOCARNO1, JAMES MONTOYA-LERMA2, ANTHONY C. BELLOTTI3 AND AART VAN SCHOONHOVEN3
1Vegetales Orgánicos C.T.A.
2Departmento de Biología, Universidad del Valle, Apartado Aéreo 25360, Cali, Colombia
3Parque Científico Agronatura, CIAT, Centro Internacional de Agricultura Tropical
Apartado Aéreo, 6713 Cali, Colombia
ABSTRACT
The larvae of some species of Scarabaeidae, known locally as “chisas” (whitegrubs), are impor-
tant pests in agricultural areas of the Cauca, Colombia. They form a complex consisting of
many species belonging to several genera that affect the roots of commercial crops. The objec-
tive of the present study was to identify the members of the complex present in two localities
(Caldono and Buenos Aires) and collect basic information on their biology, economic impor-
tance, and larval morphology. The first of two types of sampling involved sampling adults in
light traps installed weekly throughout one year. The second method involved larval collec-
tions in plots of cassava, pasture, coffee, and woodland. Each locality was visited once per
month and 10 samples per plot were collected on each occasion, with each sample from a quad-
rants 1 m2 by 15 cm deep, during 1999-2000. Light traps collected 12,512 adults belonging to
45 species and 21 genera of Scarabaeidae within the subfamilies Dynastinae, Melolonthinae,
and Rutelinae. Members of the subfamily Dynastinae predominated with 48% of the species
(mostly Cyclocephala), followed in decreasing order by Melolonthinae (35%) and Rutelinae
(15%, principally Anomala). Melolonthinae comprised 60% of the specimens (Plectris spp.
59.5% and Phyllophaga spp. 35.9%). A total of 10,261 larvae of 32 species was collected, in-
cluding 12 species each of Melolonthinae (Phyllophaga, Plectris, Astaena, Macrodactylus,
Ceraspis, Barybas, and Isonychus), Rutelinae (Anomala, Callistethus, Stigoderma, and Leu-
cothyreus) and Dynastinae (principally Cyclocephala). At least a third of the species sampled
as larvae are rhizophagous pests. Taken together, adult and larval sampling methods permit-
ted a more precise definition of the whitegrub complex in Caldono and Buenos Aires.
Key Words: beetles, scarabs, rhizophagous pests, crop pests
RESUMEN
Las llamadas “chisas” son larvas de algunas especies de Scarabaeidae, consideradas plagas
rizófagas, que actuan en complejos integrados por varias especies y géneros de difícl separa-
ción taxonómica. La presente investigación tuvo como objetivos dilucidar el complejo chisa
en Caldono y Buenos Aires, dos localidades del Departamento del Cauca. Además se obtuvo
información básica sobre su biología e importancia económica. Los adultos fueron colectados
semanalmente con trampas de luz. Las larvas se obtuvieron a partir de parcelas de yuca,
pastizal, café y bosque. Cada parcela se visitó una vez por mes, entre 1999 y 2000. Se reali-
zaron 10 muestras por parcela en cada ocasión, cada muestra consistió en cuadrantes de
1 m2 por 15 cm de profundidad. Las trampas de luz reunieron 12.512 adultos correspondien-
tes a 45 especies y 21 géneros de Scarabaeidae, la mayor diversidad correspondió a la subfa-
milia Dynastinae (48%, mayoría Cyclocephala) seguida por Melolonthinae (35%) y Rutelinae
(15%, principalmente Anomala). La mayor abundancia se observó en Melolonthinae (60%),
con Plectris spp., representando el 59.48% y Phyllophaga spp. el 35.89%). Se colectó un total
de 10.261 larvas distribuidas así: 12 especies de Melolonthinae (Phyllophaga, Plectris, As-
taena, Macrodactylus, Ceraspis, Barybas e Isonychus), 12 de Rutelinae (Anomala, Cal-
listethus, Stigoderma y Leucothyreus) y 5 Dynastinae (principalmente Cyclocephala). Se
concluye que al menos la tercera parte de las especies muestreadas a nivel de larvas presen-
tan hábitos rizófagos, además la conjugación de muestreo de larvas y adultos facilitó el re-
conocimiento del complejo chisa local lo cual se recomienda implementar en otras regiones
agrícolas con similares problemas fitosanitarios.
Translation provided by the authors.
*Only the subfamilies Dynastinae, Rutelinae and Melolonthinae.
356 Florida Entomologist 88(4) December 2005
Immature stages of some species of rhizopha- partment of Cauca (Fig. 1). Pescador was selected
gous beetles of the family Scarabaeidae (Coleop- because of previous research (Pardo-Locarno et al.
tera: Scarabaeoidea) are among the most important 1999a, b; Pardo-Locarno 2000a; Victoria & Pardo
economic pests in Colombia (Pardo-Locarno 1994; 2000a, b). Cascajeros was chosen as it represents
Londoño 1999). These insects feed on roots of vari- a different ecology. This permitted data on the
ous crops in different agro-ecological zones (Pardo- spatial heterogeneity in the region (Wiens 1989;
Locarno 1994; Pardo-Locarno et al. 2003a). They Levin 1992; Hulbert 1984).
comprise a species complex. Larvae are very similar Annual rainfall in northern Cauca fluctuates be-
and only distinguishable based on size and, less tween 2000-2300 mm and shows a bimodal pattern
precisely, body form and color of the head. Several (April-May and October-November) (IGAC, 1988).
genera and species cannot be distinguished, even The area is predominantly agricultural. Caldono is
based on these criteria. Taxonomic characters are the leading producer of sisal in the department al-
present on the mouthparts and raster, but these though as in Buenos Aires, coffee and cassava pro-
must be associated with reared specimens. duction has increased in recent years. In Buenos
Preliminary analyses are available on some of the Aires the production of fruits (oranges, lemons,
white grubs of major economic importance in Colom- guavas, etc.) predominates, followed in importance
bia, with details of species compositions, localities, by cash crops such as beans and tomatoes.
and crops affected (Pardo-Locarno 1994, 2000a; Re-
strepo & López Avila 2000). Composition of the com- Field Phase
plexes and their respective economic impact vary ac-
cording to regions and species involved (Pardo- Four plots were chosen to study composition, di-
Locarno 2000a; Pardo-Locarno et al. 2003a). The af- versity, and abundance of the white grub complex
fected agro-ecosystems represent most of the physio- in cassava, pasture, coffee, and woodland. Sam-
graphic areas of the country, including very humid pling was carried out in 1999-2000 by two meth-
tropical forest (e.g., Puerto Leguízamo) (Department ods: collection of larvae in quadrants of 1 m2 by 15
of Putumayo) and possibly the Chocó region (Pardo- cm deep and capture of adults in light traps
Locarno 2000a; Pardo-Locarno et al. 2003a). (Pardo-Locarno 2000a; Pardo-Locarno et al. 2003c,
The complex of rhizophagous beetles consti- d). Information was also collected on the crops,
tutes an important problem in cassava, sisal, feeding habits of the beetles and bioecological de-
pineapple, vegetables, flowers, and pasture in the tails. Live larvae were separated according to
municipalities of Santander de Quilichao, Buenos characters of the head, mouthparts (especially the
Aires, Toribío, and Caldono, all in the Department epipharynx), and abdomen (raster, anal opening).
of Cauca (Pardo-Locarno et al. 2003c, d; Victoria Adult sampling was carried out weekly with
& Pardo-Locarno 2000a). light traps (Pardo-Locarno, et al. 1993). On each
Studies carried out in one municipality of the occasion the specimens were stored in plastic 1-
region (Santander de Quilichao) have identified gallon containers, transported to the laboratory,
about 30 species of white grubs with different de- identified, and counted by species.
grees of economic importance to cassava cultiva-
tion and varying patterns of adult seasonal abun- Laboratory Phase
dance (Pardo-Locarno et al. 1993). The same au-
thors identified the larvae responsible for eco- Approximately 2,500 larvae were collected in
nomic damage with notes on their natural enemies different crops and allowed to complete their life
(Pardo-Locarno et al. 1999a, b). Further, feeding cycle under glasshouse conditions and identified as
preferences were established with living larvae, adults. All the specimens were reared individually
randomly collected in cassava, pasture, and other in plastic cups containing sterilized soil, rich in or-
crops and individually reared under laboratory ganic matter and supplemented with roots or
conditions (Victoria & Pardo 2000a, b). Neverthe- pieces of carrot. Field caught larvae were kept as
less, there are still many gaps in the association of individuals in disposable cups containing vapor
adults and immatures of Scarabaeidae present in sterilized soil brought from the field. Larvae were
the area. In this paper we define and compare the fed with fresh chopped carrot. Cups were inspected
regional complex of white grubs present in four once per week to control moisture and change food
agroecosystems of the municipalities of Caldono ration. Each larva was randomly labelled accord-
and Buenos Aires, Cauca, Colombia. ing to phenototypic characters observed on head,
feet, raster, and anal orifice. As soon as the adults
MATERIAL AND METHODS were obtained, the identification was verified. For
each “morpho” several voucher specimens were
Characteristics of the Study Area prepared (i.e., larvae were “cooked” in boiling wa-
ter (until they float), fixed with formalin (10%) and
Sampling was carried out in Pescador and Cas- preserved. In very few cases (i.e., larvae with rare
cajeros, localities within the municipalities of or odd characters) larvae were kept alive, and their
Caldono and Buenos Aires respectively in the De- phenotypic characteristics were drawn. For this,
Pardo-Locarno et al.: White Grub Complex in Agroecological Systems 357
Fig. 1. Map of the study area in northern Cauca, Colombia
the larva was cooled for a few minutes with ice, from Buenos Aires. This included 21 genera and 45
and cooling was repeated as many times as neces- species of Scarabaeidae belonging to the subfami-
sary (Pardo-Locarno 2002). lies Dynastinae, Melolonthinae, and Rutelinae
Several papers and taxonomic keys were con- (Table 1).
sulted for larval identification, including Ritcher The greatest species diversity was presented
(1966); Boving (1942); Morón (1993); Vallejo et al. by the subfamily Dynastinae with 48% of the spe-
(1996); Morón & Pardo-Locarno (1994); and King cies, followed in decreasing order by Melolonthi-
(1984). Identification of adults was based on the nae (35%) and Rutelinae (15%). Among the Dy-
genitalia with the aid of diagnostic keys from En- nastinae the diversity of the tribe Cyclocephalini
drödi (1985); Saylor (1942, 1945); Frey (1962, was noteworthy with 15 species identified, most
1964, 1973, 1975); Morón (1986); King (1996); belonging to the genus Cyclocephala.
Ohaus (1934); Woodruff and Beck (1989); and Members of the subfamily Melolonthinae were
Machatschke (1957, 1965). The collection of one of most abundant and comprised 60% of the total
the authors (LCP), which included representa- specimens collected. Of these, Plectris, with two
tives of many white grub species from Cauca, was species, comprised 59.5%, followed by Phyllo-
examined (Pardo-Locarno 1999a, b). We also con- phaga, with five species. Among the Dynastinae,
sulted the taxonomic specialists R.P. Dechambre the Cyclocephalini predominated, particularly
(Musee de Histoire Naturelle de Paris) and M. A. C. fulgurata Burmeister, which was especially
Morón (Instituto de Ecología de México). numerous in Caldono. Among the Oryctini, the
predominant species was Strategus aloeus L.,
RESULTS whose larvae are saprophagous and adults are
not recorded as pests of crops. This species was
Capture of Adults
followed in predominance by Podichnus agenor
Altogether 12,512 adults were collected in the Oliv. whose larvae are saprophagus and adults
light traps, with 7,562 from Caldono and 4,953 damage sugar cane stems in the region.
358 Florida Entomologist 88(4) December 2005
TABLE 1. CAPTURE OF ADULTS IN LIGHT TRAPS IN CALDONO AND BUENOS AIRES.
Species Caldono Buenos Aires Specimens
Aspidolea singularis Bates 113 20 133
Aspidolea fuliginea Burm 18 1 19
Cyclocephala sp. 1 30 30
Cyclocephala amblyopsis Bates 162 1 163
Cyclocephala amazona Linn. 2 119 121
Cyclocephala melanocephala Fabr 4 4
Cyclocephala fulgurata Burm 1607 15 1622
Cyclocephala sp. 2 2 751 753
Cyclocephala tutilina Burm 10 21 31
Cyclocephala stictica Burm 1 1 2
Cyclocephala lunulata Burm 420 115 535
Cyclocephala weidneri Endrödi 25 25
Stenocrates bicarinatus Robinson 8 14 22
Ancognatha vulgaris Arrow 1 — 1
Dyscinetus dubius Olivier 32 4 36
Coelosis biloba Linn. 14 6 20
Strategus aloeus Linn. 82 3 85
Podischnus agenor Olivier 39 1 40
Golofa porteri Hope 1 1
Ligyrus gyas Er. 1 1
Ligyrus bituberculatus Beauvois 10 4 14
Phileurus didymus Linn 3 1 4
Plectris fassli Moser. 733 3019 3752
Plectris pavida Burm 152 607 759
Phyllophaga menetriesi Blanch. 2413 9 2422
Phyllophaga obsoleta Blanch 213 29 242
Phyllophaga sericata (Blanchard) 25 25
Phyllophaga thoracica (Burmeister) 2 2
Phyllophaga schneblei Frey 29 1 30
Phyllophaga sp. 3 1 1
Astaena valida Burmeister 43 5 48
Astaena sp2. 9 9
Macrodactylus subvittatus Burm 23 23
Macrodactylus sp. 1 1 1
Macrodactylus sp. 2 11 11
Isonychus sp. 1 107 107
Isonychus sp. 2 2 2
Barybas sp. 127 22 149
Pelidnota prasina Burmeister 22 1 23
Anomala cincta Say 26 4 30
Anomala inconstans Burm 1029 9 1038
Anomala undulata Melsh. 9 9
Anomala sp. 2 121 6 127
Callisthetus sp. —
Leucothyreus sp. 19 22 41
Abundance/locality 7562 4953 12512
Members of the Rutelinae were least abun- Capture of Larvae
dant, with Anomala inconstans Burm., an agricul-
turally important species, the most numerous. A total of 10,265 larvae, representing 32 spe-
The adults of Phyllophaga spp., Plectris pavida cies of Scarabaeidae, was collected in samples
Burm., P. fassli Moser, and other Melolonthinae of from the four plots (pasture, cassava, coffee, and
economic importance were attracted to light traps woodland) in Caldono and Buenos Aires (Table 2).
mainly in October and November, although some Of the total, 52% corresponded to genera of
adults were also collected during the rainy season Melolonthinae, 25% to Dynastinae and 23% to
(March-April) and to a lesser degree in May. Rutelinae (Table 2).