SHORT COMMUNICATION
Attraction of Alates of Cryptotermes brevis (Isoptera: Kalotermitidae)
to Different Light Wavelengths in South Florida and the Azores
M. T. FERREIRA,1,2,3 P.A.V. BORGES,2
AND
R. H. SCHEFFRAHN1,2
J. Econ. Entomol. 105(6): 2213Ð2215 (2012); DOI: http://dx.doi.org/10.1603/EC12240
ABSTRACT The termite Cryptotermes brevis (Walker) (Isoptera: Kalotermitidae) is an urban pest
that causes much damage to wood structures. Little has been done concerning the use of control
methods for alates. C. brevis is known to have phototropic behavior during the dispersal ßights, and
this knowledge has been applied for preventative control in the Azores where this species is a serious
urban pest. We were interested in determining whether there was a light wavelength preference by
the alates of C. brevis to optimize light traps against this species. Six light wavelengths were tested:
395 nm (UV), 460⫺555 nm (white), 470 nm (blue), 525 nm (green), 590 nm (yellow), and 625 nm
(red) in choice chambers, with dark chambers as controls. Two populations were tested, one
population in Florida and one population in the Azores (Terceira Island). We found consistent results
for both populations, with a preference for the light wavelengths in the white, blue, and green
spectrum (460 Ð550 nm). This information can be used to build more effective light traps that can be
used by home owners in the Azores to help control this pest.
KEY WORDS alate, light wavelength, drywood termite, phototropic
The termite Cryptotermes brevis (Walker) (Isoptera:
Kalotermitidae) is an urban pest that causes much
damage to wood structures. It has a tropicopolitan
distribution and is endemic of Chile and Peru (Scheffrahn et al. 2009). The Azores is the most northern
location where this species is established, and it has
become a serious pest there (Borges 2007). The archipelago is located in the Northern Atlantic, and it
spreads out through 615 km (37Ð 40⬚ N, 25Ð31⬚ W), at
1,584 km west of southwest Europe and 2,150 km east
of the American continent. The subtropical weather in
this archipelago allows for C. brevis to prosper. The
levels of infestation in the major cities of the archipelago are elevated, and some houses are at structural
risk. This species has been spreading to other smaller
islands of the archipelago, with structures infested in
six of the nine islands (P.A.V.B. et al., unpublished
data). The spread within cities is continuous with new
infestation sites being discovered every year (P.A.V.B.
et al., unpublished data). Some of the measures that
have been used to diminish the spread of this species
within cities involve the use of light traps in infested
structures.
The seasonal ßights of C. brevis are the only time this
species is seen outside wood (Kofoid 1934), making it
a good time to apply control measures. C. brevis is
1 Fort Lauderdale Research and Education Center, University of
Florida, Institute of Food and Agricultural Sciences, Davie, FL 33314.
2 Azorean Biodiversity Group (CITA-A) and Platform for Enhancing Ecological Research & Sustainability (PEERS), Universidade dos
Açores, Dep. Ciências Agrárias, 9700-042 Angra do Heroṍsmo, Terceira, Açores.
3 Corresponding author, e-mail: [email protected].
known to ßy toward light (phototropic) during its
dispersal ßights, and high-intensity lights attract more
alates of this species (Ferreira and Scheffrahn 2011).
However, there are no data reporting whether there
is any preference by C. brevis for a speciÞc light wavelength. The purpose of this study is to determine
whether there is a preferred light wavelength that will
attract more alates of C. brevis into traps in two different populations of the species (Florida and
Azores).
Materials and Methods
Experimental Setting. Experiments were conducted at the Fort Lauderdale Research and Education Center (FLREC) Davie, FL, and in a privately
owned attic in Angra do Heroṍsmo, Terceira Island,
Azores. The experiments were set up in dark rooms
kept at ambient temperature and relative humidity
(Florida: 25.5⬚C, 73.6% RH; Azores: 20.5⬚C, 79.9% RH).
In both locations, the rooms were Þlled with C. brevisÐ
infested wood. The Florida experiment was conducted between April and June 2009, and the experiment in the Azores was conducted between July and
September 2009, the dispersal ßight season for C. brevis in each place.
Twenty-one transparent plastic boxes (36 by 23 by
28 cm) served as light wavelength preference chambers. Six different wavelengths were used: 395 nm
(UV), 460⫺555 nm (white), 470 nm (blue), 525 nm
(green), 590 nm (yellow), and 625 nm (red). There
were three replicates per wavelength. Each box was
wrapped in aluminum foil to isolate the light from one
0022-0493/12/2213Ð2215$04.00/0 䉷 2012 Entomological Society of America
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JOURNAL OF ECONOMIC ENTOMOLOGY
Vol. 105, no. 6
Fig. 1. Distribution of the different choice chambers for wavelengths. Lights were distributed randomly, with three
replicates per wavelength and three replicates with no light (controls). (Online Þgure in color.)
box to the other. Light-emitting diodes (LEDs) were
used for each wavelength (UV, model YA-UV5N30N
white, model SS5W4UAEC; blue, model SS5B4SEEC;
green, model SS5G4UAEC; yellow, model SS5Y4UAEC;
and red, model SS5R4SDEC [from theledlight.com]).
The boxes were placed against a wall in a room with
C. brevisÐinfested wood with the open end facing the
room. The different wavelengths were randomly distributed (Fig. 1). Three of the boxes had unlit lights
to serve as control. Hefty EZ Foil cake pans (21.5 cm
in diameter and 3.8 cm in depth) were placed inside
the boxes underneath the LEDs and Þlled to three
quarters with water to capture the alates ßying toward the lights. The LEDs were distanced from each
other ⬇36 cm. Alates were collected and counted
every day for all the boxes, throughout the ßight
season.
Data Analysis. The data collected from the experiments in the Azores and in Florida were separately
analyzed using an analysis of variance (ANOVA) (SAS
Institute 2003) to test whether there was any difference in the number of alates per light trap per day.
Light wavelength was used as the factor for the
ANOVA analysis. The data were transformed by
ln(x ⫹ k) where k ⫽ 2. The tested hypothesis was that
there were no differences between the variances for
the number of alates caught in the light traps per day.
Further analysis using TukeyÕs method (SAS Institute
2003) was used to determine which wavelengths were
signiÞcantly different.
Table 1.
Results
In total, 2,826 alates were captured in the light traps
with 991 alates in Florida and 1,835 alates in the
Azores. For both Florida and the Azores, the ANOVA
results showed that there were signiÞcant differences
between the number of alates in the traps per wavelength (F ⫽ 17.00 for Florida and F ⫽ 5.4 for the
Azores, df ⫽ 6; P ⬍ 0.05). Further analysis with
TukeyÕs method showed that the blue light had the
highest total number of alates in the traps but that it
was not signiÞcantly different from white, green, yellow, and UV. The red and control had the lowest total
number of alates but were not signiÞcantly different
from yellow and UV (Table 1).
Discussion
The alates ßying in both the Azores and Florida
showed a similar behavior toward the wavelength of
preference. These two different populations were
kept in different environments under different characteristics of temperature and humidity, but the results were comparable, showing that this preference is
not just a characteristic of a particular population.
When faced with choice chambers, the lights in the
wavelength of the blue, green, and white (between
460 and 550 nm) had a higher preference by alates.
Although these three wavelengths did not have signiÞcantly more alates caught than yellow or UV lights,
Total and mean number of alates caught in light traps in Florida and the Azores
Florida
Azores
Wavelength
Total no. of alates per
wavelength
Mean no. of alates per trap
per day (⫾ SE)
Total no. of alates per
wavelength
Mean no. of alates per trap
per day (⫾ SE)
Control
625 nm (red)
590 nm (yellow)
395 nm (UV)
460Ð550 nm (white)
525 nm (green)
470 nm (blue)
2
6
26
110
262
298
343
0.10 ⫾ 0.02a
0.29 ⫾ 0.06a
1.10 ⫾ 0.24ab
4.80 ⫾ 1.05ab
11.86 ⫾ 2.58b
13.62 ⫾ 2.97b
15.42 ⫾ 3.37b
79
97
228
304
377
362
388
3.29 ⫾ 0.63a
4.04 ⫾ 0.95a
9.50 ⫾ 2.37ab
12.67 ⫾ 3.05ab
15.71 ⫾ 3.17b
15.08 ⫾ 3.78b
16.17 ⫾ 4.017b
December 2012
FERREIRA ET AL.: TERMITE ATTRACTION TO LIGHT WAVELENGTHS
they were more attractive than the higher wavelength
red (625 nm) and control. Minnick et al. (1973) had
observed an attraction of the alates for UV light. UV
light is commonly used in insect traps. However, more
studies are looking into other wavelengths and their
attraction to insects. Nakamoto and Kuba (2004)
tested the effectiveness of green LEDs in light traps
against the weevil Euscepes postfasciatus (Fairmaire)
and made a case for using LEDs as opposed to more
conventional UV lights. Chang et al. (2001) looked at
alate attraction of Formosan subterranean termite,
Coptotermes formosanus Shiraki, to different light
wavelengths and found that blue (367Ð583-nm) and
green (525Ð 648-nm) lights attracted signiÞcantly
more alates of this species than the red (600 Ð733-nm)
lights and the control. Yamano (1987) also found that
winged C. formosanus response to colored lights
reached the maximum with the blue (400 Ð 420-nm)
lights.
The main reason that it was important to look at the
light wavelength preferences for C. brevis was to optimize light traps to be used during the dispersal ßight
season. Using simple LED lights that are inexpensive
can be a good way to get the public involved in preventative treatments for C. brevis in the Azores. Also,
there is lower Þre hazard, because LEDs are cold lights
and do not overheat. A simple light trap composed of
regular Christmas tree lights (nowadays composed of
LEDs) white, green or blue (for maximum attraction),
and a sticky trap, or a container with water underneath
could be recommended for use in a household. In the
Azores the main infestation sites are in the dark often
unused or cluttered attics. Promoting the use of these
simple traps, as opposed to more expensive UV light
traps, among homeowners can help slow the further
spread of this species during the dispersal ßight season.
Acknowledgments
We thank the late Boudanath Maharajh, Orlando Guerreiro, and Annabella Borges for the technical support. We
thank Ana Simões for providing laboratory facilities in a
building in the town of Angra do Heroṍsmo. We thank Michael K. Rust and anonymous reviewers whose invaluable
2215
critical comments helped improve this manuscript. Financial
support for this research was provided in part by the University of Florida, School of Structural Fumigation, the project TERMODISP (DRCT-M221-I-002-2009) and the Portuguese Foundation for Science and Technology (FCT-SFRH/
BD/29840/2006).
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Received 15 June 2012; accepted 25 July 2012.