Content uploaded by Charles E Linn
Author content
All content in this area was uploaded by Charles E Linn on Mar 21, 2016
Content may be subject to copyright.
POPULATION ECOLOGY
Temporal and Spatial Distribution of the Oriental Beetle (Coleoptera:
Scarabaeidae) in a Golf Course Environment
HENRY T. FACUNDO,
1
MICHAEL G. VILLANI, CHARLES E. LINN, JR., AND
WENDELL L. ROELOFS
2
Department of Entomology, Barton Laboratory, NYSAES, Cornell University, Geneva, NY 14456
Environ. Entomol. 28(1): 14Ð21 (1999)
ABSTRACT The mating season of the oriental beetle, Exomala orientalis (Waterhouse), in 1994
and 1995 at Bethpage State Park, Farmingdale, NY (408459N, 738289W) began in the middle of June,
peaked in the 1st wk of July, and ended in the middle of August. There were differences in the
emergence schedule among fairways as well as local differences between roughs and fairway. Both
sexes were most active around sunset on shorter-cut turf (i.e., fairways, greens, and tees, versus
roughs), and the few individuals seen during the daylight hours were mostly males. These males were
generally found perched on vegetation at the border of the fairway. Feeding was not observed, except
on ßowers by females devoid of mature eggs. This study conÞrms our observations on the pattern
of activity in an earlier study conducted with the use of synthetic pheromone traps. It also explains
the difÞculty encountered by earlier workers in Þnding adults of this insect in the Þeld. Implications
of the above Þndings on the management of the oriental beetle are discussed.
KEY WORDS Exomala orientalis, temporal and spatial distribution, golf course
THE ORIENTAL BEETLE,Exomala orientalis (Waterhouse)
(5Anomala orientalis) (Coleoptera: Scarabaeidae:
Rutelinae), has become the most important grub pest
of turf and woody ornamental plantings in the Long
Island region of New York, northern New Jersey, and
Connecticut. However, because of its relatively lim-
ited range and the cryptic nature of the adults, the
oriental beetle has not gained notoriety status like that
of the more ubiquitous and conspicuous turf pest the
Japanese beetle, Popilla japonica Newman (Scarabaei-
dae: Rutelinae). Oriental beetle grub damage in the
Northeast is still often attributed to other species,
especially the Japanese beetle. Currently, Japanese
and oriental beetle grubs are managed similarly be-
cause of the similarity between their life cycles (Alm
et al. 1995). However, differential susceptibility of
Japanese and oriental beetle grubs to soil insecticides
(Villani et al. 1988) and an insect growth regulator
(Cowles and Villani 1996) have been documented.
This underscores the need for accurate identiÞcation
of the pest causing the problem to efÞciently and
effectively use insecticides or other control measures
for environmental as well as economic reasons.
The identiÞcation and synthesis of the female sex
pheromone of the oriental beetle (Leal 1993, Zhang et
al. 1994) has led to the development of an effective
synthetic pheromone trap that has greatly facilitated
monitoring and detection of oriental beetle popula-
tions. Facundo et al. (1994) demonstrated the pher-
omoneÕs potency by catching an average of 1,000 male
beetles per trap per day in 2 golf course fairways in
Norwich, CT, using a 100-
m
g dosage of either (Z)-7-
tetradecen-2-one or an 89/11 (Z/E) blend on a rubber
septum. It was further determined that 10
m
g was the
minimum concentration with which no signiÞcant de-
crease in catch was observed. Before the development
of a pheromone trap, soil sampling for grubs was the
only way to conÞrm the presence of this species.
Grubs found in soil samples have to be identiÞed by
examining rastral patterns (arrangement of spines,
hairs, and bare spaces at the ventral area of last ab-
dominal segment just anterior to the anus), which is
the only reliable way to distinguish oriental beetle
grubs from other turf-infesting scarabs (Tashiro 1987).
In lieu of a pheromone detection system, scouting
for adults may be a viable alternative if the ecology of
the adults is well understood. Additionally, knowledge
of the adultÕs natural history and behavior may lead to
more effective use of the synthetic pheromone for the
management of this insect.
The current study was conducted to document ac-
tivities of oriental beetle adults in a golf course envi-
ronment during summer at Bethpage State Park,
Farmingdale, NY. This environment is in contrast to
earlier reports of scouting in home lawns in New
Haven, CT, by Friend (1929) and those in southeast-
ern New York by Hallock (1930), and observations
done by Bianchi (1935) in sugarcane Þelds of the Oahu
Sugar Company in Oahu, HI. SpeciÞcally, the current
study addressed the following 4 questions: (1) What is
the seasonal and daily pattern of adult emergence
from the soil? (2) Does this insect exhibit protandry
1
Current address: Department of Entomology, University of the
Philippines Los Ban˜os, College, Laguna 4031, Philippines.
2
To whom reprint requests should be sent.
0046-225X/99/0014Ð0021$02.00/0 q1999 Entomological Society of America
by guest on March 21, 2016http://ee.oxfordjournals.org/Downloaded from
or protogyny? (3) Where are adults found at different
times of the day and what are their behaviors? (4) Are
there differences between the sexes in terms of daily
as well as seasonal activities? (5) What is the abun-
dance and distribution of each of the immature life
stages found in the soil during summer?
Materials and Methods
Study Site. Unless otherwise noted, all Þeld obser-
vations and sampling were done at the 14th hole of the
Green course of Bethpage State Park, Farmingdale,
NY (408459N, 738289W). The fairway measured 180 m
long by 28 m wide with .10 m wide roughs areas at
both sides. One side of the fairway was bordered by
another fairway and the other by thick vegetation
composed of bushes, shrubs, and trees. Both the fair-
way and roughs are composed of a combination of
several grass species: perennial ryegrass (Lolium pe-
renne L.), Kentucky bluegrass (Poa pratensis L.), an-
nual bluegrass (P. annua L.), and chewing fescue (Fes-
tuca rubra commutata Gand.), with cutting heights at
1.6 and 4.3 cm, respectively.
Emergence Cones. Nine screened wire-mesh emer-
gence cones (0.6 m basal diameter and 1.0 m high)
were positioned, at least 10 m apart, at the roughs
along one side of the fairway on 29 June 1994. Care was
taken to ensure that the edges in contact with the turf
were sealed to prevent beetle escape. The cones were
monitored daily at 1000, 1400, 1800, and 2100 hours
from 30 June to 16 July 1994. An additional 9 cones
were similarly set up at the roughs of a 2nd fairway
(site 2) '250 m from the 1st. These were monitored
immediately after the Þrst 9 were checked. Monitoring
of each site took '30 min.
Turf and Soil Sections. Each day from 1 to 16 July
1994, 5Ð9 soil sections (0.3 by 0.3 by 0.2 m) were
sampled around randomly chosen emergence cones
(see above) at the 1st site. Each section was removed
'1-m radius around a cone at 1 of 8 compass points.
All samples on a given day were taken at the same
compass direction. Each section was inspected at
2.5-cm depth intervals at a time for presence of all
developmental stages of the oriental beetle. The lo-
cation in the soil of each individual was recorded and
all individuals were kept in separate 29.6-ml cups with
soil for later species identiÞcation (upon reaching the
adult stage).
Fifteen-Minute Random Walk. To determine the
seasonal ßight pattern, a 15-min random walk was
executed daily at 2130 hours from 29 June to 17 July
1994 to sample the adult population present on the
fairway surface. Based on pheromone trap catch, adult
activity is highest at 2100 hours or around sunset (Fa-
cundo et al. 1994). Monitoring was done by walking
through the fairway, turning at randomly chosen
points, with the aim of covering the entire fairway
within the 15-min period. All oriental beetle adults
encountered during the walk were captured and
placed in a resealable plastic bag for gender determi-
nation and total count.
Five-Minute Random Walk. To determine the daily
activity pattern, similar but shorter (5 min) random
walks were undertaken at 1000, 1400, 1800, and 2300
hours on 1Ð17 July 1994. Effort was made to ensure
that the entire fairway was monitored. The 2100 hours
beetle count reßected in Fig. 3 was intrapolated from
the 15-min random walk data by dividing the number
of beetles found on corresponding dates by 3.
Vegetation Visits. The vegetation at the border of
the roughs where the emergence cones were set up
was inspected for presence of oriental beetles at 1000,
1400, 1800, and 2200 hours on 1Ð5 July 1994. Each
beetleÕs sex, position on the plant, posture, pairings,
and activities such as resting, antennae waving, and
feeding were recorded.
Pheromone Trapping. To determine the onset of
the ßight season, a Trece JB trap (Salinas, CA) baited
with 10
m
gof(Z)-7-tetradecen-2-one on rubber sep-
tum (Thomas ScientiÞc, Swedesboro, NJ) and posi-
tioned such that the mouth of its funnel was at ground
level was installed at site 2 during the 1st wk of June
in 1994Ð1996. The trap was monitored daily until the
1st beetles were caught. Temperature data were ob-
tained from the Nassau County Department of Public
Works weather station in Mineola, NY (15 km west of
Bethpage State Park), to compute for degree-day ac-
cumulation at 108C base temperature. To determine
the seasonal ßight pattern using synthetic pheromone,
6 traps were installed in 6 different fairways at 2 ad-
jacent golf courses. Monitoring was done at 0800 hours
daily from 19 June to 19 July 1995. Beetles caught in
each trap were poured into individual resealable plas-
tic bags for later counting. Baits were changed every
other week.
Transect. A 312-m transect was set up across the
roughs, fairway, litter, bare soil, and other vegetation
(bushes, shrubs, trees) of hole 13 of the Black course
(site 3). In addition, to naturally occurring ßowers of
grasses and weeds, 2 small artiÞcial ßower patches
composed of roses, chrysanthemum, petunia, and
other annuals were set up. Oriental beetles found
within 1 m
2
by walking along this transect at 1000,
1200, 1500, 1800, 1900, 2000, 2100, 2200, 2300, and 2400
hours on 21 and 26 June and 6, 8, and 18 July 1995 were
noted in terms of sex, position on the plant, posture,
and activities. The following are the total areas cov-
ered by each vegetation type in square meters: fair-
way 5104, roughs 599, tall grass 523, shrub/bush 5
50, tree (mostly white pine) 513, ßower 511, and
litter/bare soil 512. The total number of males and
females found per area covered by each vegetation
type was later computed and compared using 2-way
analysis of variance (ANOVA) with time of day as the
2nd factor.
Sampling for Pupae. To test for the occurrence of
protandry in this insect, 15 additional turf and soil
sections (as described above for 1994, but only up to
a depth of 10 cm) were sampled on the edges of the
fairway of site 2 on 10 and 17 June 1996 (i.e., 5 d before
and 2 d after the 1st male was caught in 1996, respec-
tively). Pupae found were sexed, whereas larvae were
February 1999 FACUNDO ET AL.: DISTRIBUTION OF ORIENTAL BEETLE 15
by guest on March 21, 2016http://ee.oxfordjournals.org/Downloaded from
reared in 29.6-ml cups with soil for later sex determi-
nation.
Statistical Analyses. Data from the emergence
cones, 5-min random walk, and vegetation visits were
analyzed separately using the Wilcoxon signed-rank
test for the difference between sexes at each moni-
toring time, and the Friedman test for differences
among times of day for each sex (Conover 1980).
Standard error was computed and shown in graphs
where appropriate.
Other Locations. The rose gardens of Planting
Fields Arboretum, Planting Fields, NY, and Pinelawn
Cemetery, Farmingdale, NY, were inspected for the
presence of oriental beetle on roses on 15 and 17 July
1995, respectively. Activities such as feeding, mating,
and resting on the ßowers were recorded before col-
lecting the beetles. All females found were later dis-
sected for oviposition status.
Emergence Pattern in the Laboratory. Third-instar
grubs collected from Bethpage on 8 September 1996
were individually placed in 29.6-ml cups with soil and
grass seeds. These were stored at 108C and transferred
by batch of 150 individuals to 258C on 19 February and
26 March 1997. Each cup was inspected for pupae 3 wk
after the transfer to 258C (16:8 [L:D] h) and each
week thereafter. The pupae were inspected daily to
closely monitor eclosion. Male and female eclosion
patterns were compared using KolmogorovÐSmirnov
test at
a
50.05 (Siegel 1956).
Results
Seasonal Pattern
Difference Between and within Sites. The 1st male
was caught in synthetic pheromone traps on the 16th
of June 1994, the 12th of June 1995, and the 15th of
June 1996 at Bethpage State Park (357.2, 307.5, and
357.5 DD, respectively). The pattern of emergence
was unimodal with the peak occurring in the 1st half
of July (Figs. 1 and 2). However, there was signiÞcant
variation between adjacent areas (Fig. 1) and even
local differences among areas that were managed dif-
ferently, such as the roughs versus the fairway (Fig. 1
versus Fig. 3). Data from emergence cones indicate
that the 2nd site had a signiÞcantly earlier peak than
the 1st (Fig. 1; t-test on median, P,0.0001). Fig. 3
presents data from the 15-min random walk in the
fairway of the 1st site. Although no direct statistical
comparison can be made between data collected using
2 sampling methods, it can be noted that the median
dates of both males and females in the fairway (4 July;
Fig. 3) were 4 d earlier than those of the roughs (8 July;
Fig. 1). This suggests localized differences within a
small area perhaps the result of local heterogeneity in
vegetation type, grass height, soil moisture, and soil
type.
The 1995 pheromone trapping supports the appar-
ent difference in the emergence schedule between
the 2 sites (Fig. 2). The median dates were 7 July and
4 July for 1st and 2nd site, respectively, as in the 1994
season. For additional comparison, 1 other site (hole
13 of the Black course) was included in the graph. This
Fig. 1. Beetles collected from emergence cones set in
the roughs areas of 2 sites at Bethpage State Park, Farming-
dale, NY, in 1994. Arrows at the bottom indicate the dates
when median catch was reached for each site and sex.
Fig. 2. Beetles caught (mostly males) in synthetic pher-
omone traps in 3 sites at Bethpage State Park, Farmingdale,
NY, in 1995. Arrows at the bottom indicate the dates when
median catch was reached for each site; trap was not installed
on 19Ð22 June at site 1, and 20Ð23 June at sites 2 and 3.
Fig. 3. Number of beetles encountered at the fairway of
site 1 during 15-min random walks at 2130 hours. Arrows at
the bottom indicate the dates when median of the total
number of individuals collected during the monitored season
was reached for each sex.
16 ENVIRONMENTAL ENTOMOLOGY Vol. 28, no. 1
by guest on March 21, 2016http://ee.oxfordjournals.org/Downloaded from
site is '2 km away from either of the 2 main sites and
had a median date 1 d later than site 1.
Protandry. The daily cumulative adult eclosion pat-
tern of 2 batches of oriental beetle grubs reared in the
laboratory are indicative of protandry (Fig. 4). The 1st
individuals to reach the imaginal stage in each batch
were males. The 1st male to eclose for batches 1 and
2 were 8 and 11 d, respectively, earlier than their
respective 1st females. The average number of days
when 50% of males reached adulthood is 9 d earlier
than females (for details refer to location of arrows in
Fig. 4).
Sampling for pupae in 1996 immediately before and
during the start of adult emergence has yielded data
verifying the trend observed in the laboratory (Table
1). Before the mating season (10 June), signiÞcantly
more male pupae (274.11 6186.67/m
3
) than female
pupae (96.33 692.22/m
3
) were unearthed; whereas,
1 wk later during the start of the mating season, there
was no signiÞcant difference between the 2 pupae
populations (251.89 649.00 versus 229.67 633.33/m
3
,
respectively). The only adult beetles found in the soil
on the 17 June 1996 sampling were males (Table 1).
In 1994, data on the males and females and teneral
adults sampled in the soil during the mating season are
indicative of protandry as well. The date when half of
all mature males unearthed throughout the monitored
season were found was 3 d earlier than that of females
(6 and 9 July, respectively; Fig. 5). More males were
found at the onset of the monitored season, and then
the sex ratio changed to '50:50. In contrast, more
teneral females than teneral males were found
throughout the monitored season (Fig. 5).
Differences Among Developmental Stages. Fig. 5
shows the mean number of each developmental stage
found in the soil blocks sampled around the cones.
There was a dramatic decrease in the number of pupae
sampled after 3 July 1994, followed by an increase in
the number of teneral adults. Third instars were
present throughout the monitored season, the late
ones presumably overwintering the 2nd time (2-yr
cycle; Tashiro 1987). Only three 2nd-instar grubs were
found.
Daily Pattern
Time of Day. SigniÞcantly more males and females
were collected in the emergence cones at 2100 hours
than at any other time (Fig. 6). Data from 5-min
random walks in the fairway of site 1 at different times
Fig. 4. Daily cumulative adult eclosion in the laboratory
at 258C of 2 batches of 150 grubs collected on 8 September
1996 at Bethpage State Park, Farmingdale, NY. Total number
of eclosed males and females for batch 1 were 20 and 19,
respectively; and 20 and 12, respectively, for batch 2. Male
and female distributions were signiÞcantly different for the
2 batches (P,0.001 and P,0.01, respectively) using the
KolmogorovÐSmirnov test. Arrows at the bottom indicate the
dates when median of the total number of individuals that
eclosed was reached for each sex and batch.
Table 1. Mean number of males and females of each stage sampled before and during the start of adult emergence at Bethpage State
Park, Farmingdale, NY (date of 1st male caught in pheromone trap is 15 June 1996)
Sampling date *Mean no./m
3
Adults
a
Pupae Prepupae Larvae
10 June 1996
Male 0 274.11 6186.67a 22.22 611.89a 22.22 611.89a
Female 0 96.33 692.22b 14.78 610.11a 29.67 613.11a
Unknown sex
b
Ñ 96.33 6151.11 281.44 638.89 103.67 629.67
17 June 1996
Male 22.22 611.89a 251.89 649.00a 0 7.44 67.44a
Female 0b 229.67 633.33a 0 22.22 611.89a
Unknown sex
b
Ñ 14.78 610.11 51.89 618.33 29.67 613.11
Means followed by the same letter for each stage and sampling data are not signiÞcantly different (paired t-test,
a
50.05).
a
P50.082 for male versus female adults sampled on 17 June 1996.
b
All pupae whose sex were undetermined were crushed during sampling in the Þeld. All prepupae whose sex were undetermined died before
reaching the pupal stage during laboratory rearing. Fourteen and 25% of larvae whose sex were undetermined for 10 and 17 June, respectively,
were crushed during sampling, and the rest died during laboratory rearing without reaching the pupal stage.
February 1999 FACUNDO ET AL.: DISTRIBUTION OF ORIENTAL BEETLE 17
by guest on March 21, 2016http://ee.oxfordjournals.org/Downloaded from
of the day also showed this pattern (Fig. 7) and is
consistent with a previous study (Facundo et al. 1994)
in which pheromone and blacklight traps were used.
In surrounding vegetation (bushes, shrubs, and trees),
however, there was no signiÞcant differences in the
number of beetles present at different times of the day
(Fig. 8). Observations and data on the 1995 transect at
a different site corroborate the 1994 data. The 1995
transect data conÞrmed that the oriental beetle is a
crepuscular/nocturnal insect, being most active at the
Þrst2hofthescotophase (Friedman test, P,0.05).
The above-mentioned difference between beetle
presence in fairways versus surrounding vegetation
will be discussed in the section on spatial distribution.
Difference Between Sexes. One obvious difference
between males and females is the greater presence of
males at all times in both the fairway (Fig. 7) and the
surrounding vegetation (Fig. 8). Male beetles perch
on surrounding vegetation mostly within the 1st m
from the ground. Feeding by males was rarely ob-
Fig. 5. Soil sampling data showing counts of individuals
of different developmental stages found throughout the mon-
itored season. Arrows at the bottom indicate the dates when
half of the mature males and females unearthed throughout
the monitored season were found.
Fig. 6. Beetles collected from emergence cones at dif-
ferent times of the day from 30 June to 16 July 1994. Bars of
the same kind with the same letter (and superscript) are not
signiÞcantly different at
a
50.001. For comparison between
sexes: *,P,0.05; **,P,0.01; ***,P,0.001.
Fig. 7. Number of beetles encountered in 5-min random
walks on the fairway of site 1 in 1994. Bars of the same kind
with the same letter (and superscript) are not signiÞcantly
different at
a
50.05. For comparison between sexes: *,P,
0.05; **,P,0.005; ***,P,0.001.
Fig. 8. Number of beetles encountered during visual
inspection of vegetation on the border of site 1 in 1994. Bars
of the same kind with the same letter (and superscript) are
not signiÞcantly different at
a
50.05. For comparison be-
tween sexes: *,P,0.05; 0,P,0.068.
18 ENVIRONMENTAL ENTOMOLOGY Vol. 28, no. 1
by guest on March 21, 2016http://ee.oxfordjournals.org/Downloaded from
served and mating was not observed on surrounding
bushes, shrubs, or pine trees.
Females, by comparison, were rarely seen perched
on nearby vegetation. The small number seen during
the day were mostly on turf and this number slowly
increased to a peak at around sunset. Females are
behaviorally more cryptic, emerging from the soil
when light intensity decreases and immediately going
back to soil after mating (H.T.F., unpublished data;
also observed in the laboratory, see Facundo et al.
1999).
Spatial Distribution
Most individuals unearthed in all developmental
stages were within 10 cm from the surface (Fig. 9).
Second-instar grubs were found at the Þrst 7.5 cm of
the soil proÞle. Although 3rd-instar grubs were mostly
in the upper 5.0 cm, many were also found below 5.0
cm. This 3rd-instar population may be composed of
those still feeding within the root zone at the Þrst 5.0
cm, and those moving down to pupate. Pupae, how-
ever, seem to prefer the portion of the soil proÞle
.2.5Ð12.5 cm. As expected, teneral adults were found
at depths .5.0Ð10.0 cm, which is within the zone
where most pupae were located. Adults were found
within the upper half of the sampled proÞle (Fig. 9).
Above ground, males are more likely to be found on
fairways at around dusk, and on bushes, shrubs, and
low-growing plants at the border of the course
throughout the day (Fig. 10, see also Figs. 7 and 8).
While perched, they stay on leaves of low-growing
plants (as well as leaves or needles of trees) within
0.3Ð1.0 m high. Females, however, are generally only
visible around sunset and are found more in the fair-
way than in any other part of the golf course envi-
ronment (Figs. 10 and 7 and 8). Most pairings occur on
fairways and areas with shorter-cut turf and coincides
with this female emergence from the soil.
Adults found feeding and perched on ßowers, es-
pecially roses and chrysanthemum, were mostly fe-
males. Although no statistical difference exists be-
tween the sexes on ßowers in the transect data (Fig.
10), collections in the rose gardens of Pinelawn Cem-
etery (45 females out of 51 individuals found on roses)
and of Planting Fields Arboretum (14 out of 16) con-
Þrm the sex bias. Dissection of the reproductive tracts
revealed that the majority of females found on roses
did not have mature eggs, indicating that these were
older females who had oviposited (mean mature eggs
Fig. 9. Soil sampling data showing counts of various stages found within different depths.
February 1999 FACUNDO ET AL.: DISTRIBUTION OF ORIENTAL BEETLE 19
by guest on March 21, 2016http://ee.oxfordjournals.org/Downloaded from
per female 51.53; n545; range 0 Ð14; versus 21.2 eggs
per female in virgin females, n510; range, 13Ð37;
Facundo 1997).
Discussion
In this study, the mating season of the oriental bee-
tle at Bethpage commenced in mid-June, peaked dur-
ing the 1st half of July, and decreased toward mid-
August. There was a signiÞcant difference (4 d at most,
based on dates of median catch) in emergence sched-
ules between fairways and even within a local area
(e.g., the fairway versus the roughs). This variation
may be of importance in planning sampling and con-
trol techniques involving pheromones. A case in point
is the use of this pheromone to predict grub density in
the subsequent fall. If shorter term adult sampling
during the summer using synthetic pheromone is pre-
ferred over season-long sampling, a 4-d difference in
emergence pattern between fairways can potentially
complicate the analysis of a single day sampling or
reduce its predictive value. Therefore, a nightly trap-
ping schedule that spans this difference (e.g., 4 suc-
cessive nights of trapping) might be essential to dilute
such discrepancies and in effect make the emergence
schedule in different locations more uniform.
A major goal of the current study was to examine the
temporal and spatial distribution of beetles without
using the synthetic pheromone. In terms of daily ac-
tivities, although earlier workers reported that noc-
turnal activities occur (Johnson 1927, Friend 1929),
the general perception has been that the beetle is most
active during the day, with most ßights occurring be-
tween 0800 and 1600 hours, especially during very
warm and sunny days (Hallock 1930, 1933). With the
development of a synthetic pheromone trap, it has
been demonstrated that the crepuscular and noctur-
nal movements are more important than previously
thought, in that most ßights occur around sunset (Fa-
cundo et al. 1994). The current study supports the
results obtained in 1993 (Facundo et al. 1994) in terms
of the peak of daily activity, and it also explains the
difÞculty of earlier workers in Þnding the adults in the
Þeld. The relatively small number of ßights observed
during the day may be the result of male response to
calling females or a response to high soil, thatch, and
crown temperatures. In the case of the former, it is not
uncommon to Þnd males converging to a common
point (a calling female), which may explain the in-
stances when earlier workers found oriental beetles
“swarming like bees over lawns”during the day (Hal-
lock 1930). In the latter case, temperatures at ground
level could be fatal during some parts of the day (e.g.,
42.22 61.278C at 1130 hours; Facundo 1997). Close
observations showed that some males tend to stay at
ground level within the thatch or crown area of the
turf while extending their antennae to the air (also,
Facundo et al. 1999). Similarly, females may call
Fig. 10. Standardized transect data showing relative abundance of oriental beetles at different area (vegetation) of site
3 in 1995. Bars with the same letter (and superscript) are not signiÞcantly different at
a
50.05. For comparison between sexes
at speciÞc vegetation type: *,P,0.05.
20 ENVIRONMENTAL ENTOMOLOGY Vol. 28, no. 1
by guest on March 21, 2016http://ee.oxfordjournals.org/Downloaded from
(with their posterior end up and head in the turf; see
Facundo et al. 1999) during the day without being
noticed if not for the presence of converging males.
The difference between males and females in terms
of their behavior and spatial distribution with respect
to vegetation type should facilitate identiÞcation and
scouting. Both sexes are mostly found on short-cut turf
especially around sunset. Males also are found perch-
ing on low-growing plants on the border of the course,
whereas only females are found feeding on ßowers.
The search for and feeding on ßowers by oriental
beetle females that had oviposited might be the only
natural mode of dispersal of this species, especially
because females generally call, mate, and deposit their
eggs within a very small radius from the point of
emergence from the soil (Facundo 1997, Facundo et
al. 1999). Flowers apparently provide additional nu-
trients for a femaleÕs subsequent oviposition bout(s);
as such, females were able to oviposit an additional
5.46 60.96 fertile eggs (Facundo 1997). If this is the
only natural mode of dispersal, then the natural spread
of this beetle would be slow. This speculation is con-
sistent with the observed general consistency and lim-
ited local infestation year after year and the beetleÕs
present limited range in the United States (Facundo
1997). Bianchi (1935) also made such a supposition to
explain the slow rate of spread of the oriental beetle
in Hawaii, because he occasionally found females that
were mostly devoid of mature eggs in copula on ßow-
ers that were removed from the focus of grub infes-
tation in a sugarcane Þeld. Hallock (1930) speculated
that natural spread was slow because oriental beetles
were rarely engaged in long ßights and thus shipment
of infested sod, rose blossoms with hidden females,
and other infested plants with ball of earth was of
considerable importance in the spread of this insect.
Acknowledgments
We thank Jim Evans and Bruce Lattmann of Bethpage
State Park for their generous cooperation and ample toler-
ance to the inconveniences that go with researches like this.
Tracy Wilson and a number of her crew are also acknowl-
edged for their help in monitoring the traps. Maria Cinque
and Kevin Masarik of the Cornell Cooperative Extension,
Nassau County, also assisted in the monitoring of season-long
traps in 1996. We also thank Patricia Duncan-Grady of Plant-
ing Fields Arboretum and Samuel Boiko of Pinelawn Cem-
etery for allowing us to conduct observations and collect
grubs at those sites. Much gratitude is due to Dan Gilrein of
the Long Island Horticultural Research Laboratory and Scott
Clark of the Cornell Cooperative Extension, Suffolk County,
for their help in the logistics. Loretta V. Dionisio of Nassau
County Department of Public Works provided us with tem-
perature data from 1994 Ð1996. Charles Eckenrode lent us the
emergence cones. Alison Power and Cole Gilbert are also
hereby thanked for their comments and suggestions in the
original manuscript. This study was funded in part by NE-
integrated pest management grant no. 94-34103Ð0126 and a
W. Arthur and Alma D. Rawlins Endowment to H.T.F.
References Cited
Alm, S. R., M. G. Villani, and M. G. Klein. 1995. Oriental
beetle, pp. 81Ð83. In R. L. Brandenburg and M. G. Villani
[eds.], Handbook of turfgrass insect pests. The Entomo-
logical Society of America, Lanham, MD.
Bianchi, F. A. 1935. Investigations on Anomala orientalis
Waterhouse at Oahu Sugar Company, Ltd. Hawaii. Plant.
Rec. 39: 234Ð255.
Conover, W. J. 1980. Practical nonparametric statistics, 2nd
ed. Wiley, New York.
Cowles, R. S., and M. G. Villani. 1996. Susceptibility of Jap-
anese beetle, oriental beetle, and European chafer (Co-
leoptera: Scarabaeidae) to halofenozide, and insect
growth. J. Econ. Entomol. 89: 1556Ð1565.
Facundo, H. T. 1997. The reproductive ecology of the ori-
ental beetle, Exomala orientalis (Waterhouse) (Co-
leoptera: Scarabaeidae). Ph.D. dissertation. Cornell Uni-
versity, Ithaca, NY.
Facundo, H. T., A. Zhang, P. S. Robbins, S. R. Alm, C. E. Linn,
Jr., M. G. Villani, and W. L. Roelofs. 1994. Sex phero-
mone responses of the oriental beetle (Coleoptera: Scar-
abaeidae). Environ. Entomol. 23: 1508Ð1515.
Facundo, H. T., C. E. Linn, Jr., M. G. Villani, and W. L.
Roelofs. 1998a. Emergence, mating and mate-locating
behaviors of the oriental beetle, Exomala orientalis (Co-
leoptera: Scarabaeidae). Insect Behav. (in press).
Friend, R. B. 1929. The Asiatic beetle in Connecticut. Conn.
Agric. Exp. Stn. Bull. 304: 585Ð664.
Hallock, H. C. 1930. The Asiatic beetle, a serious pest in
lawns. U.S. Dep. Agric. Circ. 117: 7.
Hallock, H. C. 1933. Present status of two Asiatic beetles
(Anomala orientalis and Autoserica castanea)inthe
United States. J. Econ. Entomol. 26: 80Ð85.
Johnson, J. P. 1927. Soil treatment and scouting for the con-
trol of the Asiatic beetle. J. Econ. Entomol. 20: 373Ð376.
Leal, W. S. 1993. (Z)- and (E)- Tetradec-7-en-2-one, a new
type of sex pheromone from the oriental beetle. Natur-
wissenschaften 80: 86Ð87.
Siegel, S. 1956. Nonparametric statistics for the behavioral
sciences. McGraw-Hill, New York.
Tashiro, H. 1987. Turfgrass insects of the United States and
Canada. Cornell University Press, Ithaca, NY.
Villani, M. G., R. J. Wright, and P. B. Baker. 1988. Differ-
ential susceptibility of Japanese beetle, oriental beetle,
and European chafer (Coleoptera: Scarabaeidae) larvae
to Þve soil insecticides. J. Econ. Entomol. 81: 785Ð788.
Zhang, A., H. T. Facundo, P. S. Robbins, C. E. Linn, Jr., J. L.
Hanula, M. G. Villani, and W. L. Roelofs. 1994. Identi-
Þcation and synthesis of female sex pheromone of oriental
beetle, Anomala orientalis (Coleoptera: Scarabaeidae).
J. Chem. Ecol. 20: 2415Ð2427.
Received for publication 23 September 1997; accepted 16
September 1998.
February 1999 FACUNDO ET AL.: DISTRIBUTION OF ORIENTAL BEETLE 21
by guest on March 21, 2016http://ee.oxfordjournals.org/Downloaded from