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Body mass and wing geometric morphology of the codling moth (Lepidoptera: Tortricidae) according to sex, location and host plant in the region of Maule, Chile

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Codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is the key pest of apple and walnut production worldwide. Among other variables, successful management of this pest is dependent on adult dispersal at the local scale. Body mass and wing geometric morphology were evaluated on female and male codling moth adults collected from apple and walnut trees in three localities of the Region of Maule. Codling moth adults were obtained by rearing diapausing larvae collected from the field. Newly emerged adults were killed, and the total dry weight, thorax weight and abdomen weight were calculated. The wings were cleared and mounted for morphometric analyses: 15 and 11 characteristics of the fore and hind wings, respectively, were measured, including the meeting points of the veins and attaching points to the margins. In addition, wing length, area, loading, and aspect ratio were evaluated. As previously reported, females showed larger thorax, abdomen and total body mass, with longer, larger, and wider wings than males but with similar wing loading as males. The geometric morphology analysis also confirmed a sexual dimorphism in the fore and hind wings' size and shape. Significant differences in body mass and wing loading were found between localities, with morphological differences detected in the fore and hind wing shape but not in size. Host plant (apple and walnut) did not influence body mass, wing size or shape variables. Potential consequences of body mass and wing morphology differences on the dispersal and management of this major pest are discussed.
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Cien. Inv. Agr. 42(3):397-406. 2015
www.rcia.uc.cl
crop protection
research paper
Body mass and wing geometric morphology of the codling moth
(Lepidoptera: Tortricidae) according to sex, location and host plant in
the region of Maule, Chile
Fa b i o l a Tor re s1, Marcela A. Rodríguez1,2, Blas Lavandero3, and Eduardo
Fuentes-Contreras1
1Millennium Nucleus Center in Molecular Ecology and Evolutionary Applications in the Agroecosystems
(CEM), Facultad de Ciencias Agrarias, Universidad de Talca. Casilla 747, Talca, Chile.
2Departamento de Zoología, Facultad de Ciencias Naturales y Oceanográcas, Universidad de Concepción,
Casilla 160C, Concepción, Chile.
3Millennium Nucleus Center in Molecular Ecology and Evolutionary Applications in the Agroecosystems
(CEM), Instituto de Ciencias Biológicas, Universidad de Talca. Casilla 747, Talca, Chile.
Abstract
F. Torres, M.A. Rodríguez, B. Lavandero, and E. Fuentes-Contreras. 2015. Body mass and
wing geometric morphology of the codling moth (Lepidoptera: Tortricidae) according to
sex, location and host plant in the region of Maule, Chile. Cien. Inv. Agr. 42(3): 397-406.
Codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is the key pest of apple and
walnut production worldwide. Among other variables, successful management of this pest is
dependent on adult dispersal at the local scale. Body mass and wing geometric morphology were
evaluated on female and male codling moth adults collected from apple and walnut trees in three
localities of the Region of Maule. Codling moth adults were obtained by rearing diapausing larvae
collected from the eld. Newly emerged adults were killed, and the total dry weight, thorax weight
and abdomen weight were calculated. The wings were cleared and mounted for morphometric
analyses: 15 and 11 characteristics of the fore and hind wings, respectively, were measured,
including the meeting points of the veins and attaching points to the margins. In addition, wing
length, area, loading, and aspect ratio were evaluated. As previously reported, females showed
larger thorax, abdomen and total body mass, with longer, larger, and wider wings than males but
with similar wing loading as males. The geometric morphology analysis also conrmed a sexual
dimorphism in the fore and hind wings’ size and shape. Signicant differences in body mass
and wing loading were found between localities, with morphological differences detected in the
fore and hind wing shape but not in size. Host plant (apple and walnut) did not inuence body
mass, wing size or shape variables. Potential consequences of body mass and wing morphology
differences on the dispersal and management of this major pest are discussed.
Key words: Apple, aspect ratio, Cydia pomonella, landmark-analysis, MorphoJ, walnut, wing
loading
Received March 15, 2015. Accepted July 24, 2015.
Corresponding author: efuentes@utalca.cl
DOI: 10.4067/s0718 -16202015000300008
Introduction
Codling moth, Cydia pomonella L. (Lepidoptera:
Tortricidae), is the major pest of pome fruits
(apple, pear, and quince) and walnut worldwide
(Barnes, 1991). The control of this pest has been
based on regular sprays of synthetic insecticides;
in some areas, mating disruption and granulovirus
applications are also key components of manage-
ment programs (Witzgall et al., 2008; Weddle et
al., 2009). The spatial population dynamics of
ciencia e investigación agraria398
the codling moth can affect these control strate-
gies in several ways (Mazzi and Dorn, 2012).
Landscape, orchard and tree canopy structure
inuence codling moth dispersal at the local
scale and thus its spatial population dynamics
(Stoeckl i et al., 2008; Ricci et al., 2009, 2011).
The selection of insecticide-resistant individu-
als in orchards under regular insecticide sprays
could be reduced by immigration and gene ow
of susceptible individuals from unmanaged
areas (Basoalto et al., 2010, Fuentes-Contreras
et al., 2014). Furthermore, a decrease in mat-
ing disruption efcacy is well-documented as a
consequence of the immigration of mated females
from unmanaged areas, especially in orchard
borders, as well as from high density populations
or small orchard sizes with high perimeter-area
relationship (Witzgall et al., 2008).
Some studies in codling moth have found an as-
sociation between insecticide resistance, body
size, and sexual dimorphism because females
have higher levels of resistance compared with
males, which usually are of smaller body size
(Vare la et al., 1993; Sauphanor et al., 2000;
Reyes et al., 2004, 2015; Fuentes-Contreras et
al., 2007). Body size has also been related to
dispersal capability in the codling moth: in the
same population, larger females tend to be more
fecund, live longer, and disperse less than smaller
females (Gu et al., 2006). Flight distance was also
negatively correlated with body weight and wing
size in the codling moth, suggesting a trade-off
between tness and dispersal for this species
(Schumacher et al., 1997a). Sex dimorphism in
the codling moth is apparent in the body size,
wing size, and wing shape, as detected using wing
geometric morphology analyses (Khaghaninia
et al., 2011a), and factors such as altitude and
geographic origin affect wing morphometrics
(Khaghaninia et al., 2011b).
Few other studies suggest the existence of differ-
ent apple and walnut races of the codling moth
(Cisneros and Barnes, 1974; Phillips and Barnes,
1975), although genetic studies have found little
genetic differentiation between apple and walnut
populations (Buès et al. 1995; Thaler et al., 2008;
Franck and Timm, 2010). To our knowledge, no
studies on body size or wing morphology have
been performed with codling moth from differ-
ent host plants, although such differences could
be important for the insecticide resistance and
dispersal capabilities of this pest species.
Our aim was to evaluate whether body size and
several wing morphometric variables of codling
moth populations differ between sex, locality and
host plant in the Region of Maule, Chile. This
information could shed light on the patterns of
insecticide resistance and codling moth disper-
sal in central Chile, which could contribute to a
more successful management of this pest under
rotation of insecticides with different modes of
action between codling moth generations.
Materials and methods
Insect sampling and rearing
Cardboard traps were strapped around tr unks
in unsprayed backyard apple and walnut trees at
the end of the summer in the Region of Maule
(Februar y 2013), Chile. Apple and walnut trees,
usually growing together, were sampled in each of
these three localities: Las Cruces (35º45’43,11’’S,
71º62’10,66’’W), Orilla de Maule (35º63’ 39,70’’S,
71º41’89,07’’W), and Yerbas Buenas (35º74’64,07’’S,
71º58’57,01’’W). One apple and one walnut tree
were sampled in Orilla de Maule and Yerbas
Buenas, whereas six apple and two walnut trees
were sampled in Las Cruces. The cardboard traps
were removed in autumn (April 2013) and brought
ba ck to the labor at ory to obtai n ft h ins tar larvae
in diapause. A minimum of fty larvae were sexed
and maintained for three months at 10 ± 1 °C and
a 12:12 (L:D) photoperiod to complete diapause.
Larvae were then transferred to 24 ± 1 °C and a
16:8 (L:D) photoperiod to promote diapause break
and to obtain adults. Less than 1-day old adults
were killed to prevent wing damage caused by
399
VOLUME 42 Nº3 SEPTEMBER – DECEMBER 2015
igh t inside smal l conta iners and were pre se r ve d
in 95% ethanol for further analyses. A sample size
of ten individuals (N = 10) for each sex, location
and host plant combination was used for body
mass and wing morphometric measurements.
Body mass evaluation and wing mounting
Adult insects were removed from the alcohol and
dried at 45 °C for 48 h to evaluate their total dry
mass (m), expressed in mg, using a microbalance
(Mettler Toledo XS, Greifensee, Switzerland).
After weighing, the fore and hind wings, head, and
legs were carefully removed to weigh the thorax
(t) and abdomen (a) separately, as described by
Norberg and Leimar (2002). The right pair of wings
was then transferred to 70% ethanol to induce a
partial rehydration for two hours. The wings were
placed in a sodium hypochlorite solution (5%) for
ve minutes, and the scales were removed with
a ne brush. The wings were then cleared with
a potassium hydroxide solution (5%), and then
glacial acetic acid solution (5%) was added to
stop the alkaline reaction. The wings were gen-
tly washed with eugenol and left in 95% alcohol
overnight. Finally, the wings were mounted on
a slide/coverslip with Neo-Mount media (Merck
Millipore, Darmstadt, Germany).
Wing morphology and geometric morphometric
measurements
Geometric morphometrics of the wings were
calculated using landmark analysis (Bookstein,
1986) to address the possible inuence of sex,
location and host plant on wing size and shape.
Fifteen and eleven landmarks were dened for
the fore and hind wings, respectively, which cor-
respond to the meeting points of the veins and
attaching points of the veins and wing margins
(Type I landmarks), as described for this species
by Khaghaninia et al. (2011a,b). Images with 10X
ma gni cation were ta ken with th e soft ware Optika
Vision Pro using a stereoscopic microscope with
a digital camera (SMZ 2, Optikam Pro5, Optika,
Pontenarica, Italy). Two-dimensional coordinates
of the landmarks were obtained with TpsDIG 2
software (Rohlf, 2006). Coordinate data were
transformed to shape variables and partial warp
scores with MorphoJ 1.03a software (Klingen-
berg , 2011).
Dry body mass in relation to wing size and area
was used to estimate the wing loading and aspect
ratio, as dened by Betts and Wootton (1988).
Wing morphology measurements were performed
as follows: i) wing length (R) was the maximum
length (mm) from forewing base to apex, ii) wing
area (S) was the total area (mm
2
) of both fore and
hind wings, iii) wing loading (Pw) was the ratio
between total dry mass and wing area mS-1 (mg
mm-2), and iv) aspect ratio (AR) was the ratio
between four times the square of the wing length
and wing area (4R2S-1).
Statistical analyses
Sig n ican t differe nces between bod y dry mass (t,
a, and m) and wing morphology variables (S, R,
Pw and AR) were performed with a generalized
linear model (GLM) using the package glm in
R (R Development Core Team, 2014). A gamma
error distribution with a logarithmic link func-
tion was used. Sex, host plant, location and their
interactions were considered as xed effects.
Model selection was performed according to
Crawley (2013), using the package car in R. In all
cases, we selected the additive model because the
interaction model was not signicantly better and
showed the lowest value of the Akaike informa-
tion criterion (AIC). Contrasts between pairs of
treatments were calculated using the multcomp
package in R following Bretz et al. (2011).
Procrustes superimposition removed the varia-
tion not related to shape, and the residuals were
analyzed with ANOVA using MorphoJ 1.03a
software (Klingenberg, 2011) to evaluate the
decomposition of the geometric morphological
ciencia e investigación agraria400
χ2 = 48.4, df = 1, P≤0.001; S: χ2 = 59.8, df = 1,
P≤0.001) (Table 2). Signicant differences in Pw
were found between localities (χ2 = 41.6, df =
2, P≤0.001), but not between sex (χ2 = 3.2, df =
1, P = 0.07) or host plant (χ2 = 0.04, df = 1, P =
0.84). Pw was signicantly higher in wings from
Orilla de Maule than in wings from Las Cruces
and Yerbas Buenas (Table 2). Finally, AR was
signicantly higher in males than in females (χ2
= 14.9, df = 1, P≤0.001), without signicant dif-
ferences by locality (χ2 = 0.7, df = 2, P = 0.72) or
host plant (χ2 = 0.05, df = 1, P = 0.84).
Wing geometric morphology
Pr ocr ust es ANOVA showed sig n icant ef fe cts of
sex on wing size (fore wings MS = 1273003, F(1, 11 8)
= 54.7, P≤0.001; hind wi ngs MS = 983139, F(1 , 118)
= 58. 8, P≤0.0 01) bu t no t for host pla nt or lo ca tion.
Similarly, signica nt effects on wing shape wer e
found for sex (fore wings MS = 0.00034, F(26, 3 068)
= 3.5, P≤ 0.001; hi nd wi ng s MS = 0.0 064 4, F(18, 21 24)
= 23.1, P≤0.001) and location (fore wings MS =
0.00024, F(52, 3042) = 2.5, P≤0.0 01; hind wings MS
= 0.00081, F
(36, 2106)
= 2.5, P≤0.001) but not for host
variation between individuals and independent
variables (sex, host plant and location). Furthermore,
canonical variation and discriminant function
analyses were performed with the same software.
Results
Body mass and wing morphology
Thorax (t), abdomen (a) and total dry body mass
(m) showed signicant differences between sex
(t: χ2 = 40.4, df = 1, P≤0.001; a: χ2 = 39.9, df = 1,
P<0.001; m: χ
2
= 50.0, df = 1, P≤0.0 01) and local -
ity (t: χ2 = 6.6, df = 2, P≤0.05; a: χ2 = 30.4, df =
2, P≤0.001; m: χ2 = 21.7, df = 2, P≤0.0 01), but not
between host plants (t: χ2 = 0.2, df = 1, P = 0.67;
a: χ2 = 0.3, df = 1, P = 0.56; m: χ2 = 0.5, df = 1, P
= 0.47) (Table 1). Females had higher t, a and m
than males (Table 1). Regardless of host plant and
sex, adults from Oril la de Ma ule has sig nica ntly
heavier t, a and m than those obtained from Las
Cruces and Yerbas Buenas (Table 1).
Regardless of locality or host plant, females
had signicantly larger R and S than males (R:
Table 1. Mean ± SE dry mass (mg) of adult codling moth thorax (t), abdomen (a) and full body (m) from males and females
obtained from dif ferent host plants and localities in the Maule Region, Ch ile.
Mean ± SE dry mass (mg)1
Male Female
Locality Host t a m t a m
Las Cruces Apple 1.29 ± 0.08 1.91 ± 0.10 4.12 ± 0.22 1.74 ± 0.12 2.81 ± 0.30 5.59 ± 0.49
Walnut 1.21 ± 0.03 2.23 ± 0.15 4.28 ± 0.18 1.49 ± 0.14 2.65 ± 0.21 5.15 ± 0.43
Mean21.25 ± 0.06 b 2.07 ± 0.13 b 4.20 ± 0.20 b 1.62 ± 0.13 b 2.73 ± 0.25 b 5.37 ± 0.45 b
Orilla de
Maule
Apple 1.34 ± 0.06 2.72 ± 0.19 4.88 ± 0.24 1.82 ± 0.18 4.06 ± 0.53 7.0 ± 0.73
Walnut 1.45 ± 0.09 2.90 ± 0.23 5.23 ± 0.34 1.90 ± 0.14 4.13 ± 0.40 7.55 ± 0.48
Mean 1.40 ± 0.08 a 2.81 ± 0.20 a 5.05 ± 0.29 a 1.86 ± 0.16 a 4.09 ± 0.45 a 7.27 ± 0.61 a
Yerbas Buenas Apple 1.46 ± 0.10 2.61 ± 0.16 4.91 ± 0.25 1.71 ± 0.14 3.04 ± 0.34 5.79 ± 0.53
Walnut 1.28 ± 0.06 2.14 ± 0.15 4.31 ± 0.17 1.81 ± 0.20 3.70 ± 0.47 6.64 ± 0.74
Mean 1.37 ± 0.09 b 2.37 ± 0.17 b 4.61 ± 0.23 b 1.76 ± 0.17 b 3.37 ± 0.41 b 6.22 ± 0.64 b
Grand Mean31.34 ± 0.08 B 2.42 ± 0.19 B 4.62 ± 0.26 B 1.75 ± 0.15 A 3.40 ± 0.42 A 6.28 ± 0.62 A
1Sample size N = 10.
2Small letters indicate signi cant differences between localities in each column.
3Capital let ters indicate signicant dif ferences between sex columns.
401
VOLUME 42 Nº3 SEPTEMBER – DECEMBER 2015
plant. Canonical variation analysis showed that the
rst and second canonical variates accounted for
29.3% and 18.8% of the variance in the fore wings,
respectively, and 50.0% and 18.5% of the variance
in the hind wings, respectively. Discriminant
function analysis showed signicant differences
between sex (fore wings Mahalanobis distance =
2. 21, t2 = 146.2 , P≤0.001; hi nd wi ngs Mah alanobis
distance = 2.62, t
2
= 205.5, P≤0.001) and be tween
some locations, as follows: Las Cruces and Orilla
de Maule (fore wings Mahalanobis distance =
1.80, t
2
= 64.5, P = 0.05; hind wings Mahalanobis
distance = 0.99, t2 = 19.6, P = 0.63), Las Cruces
and Yerbas Buenas (fore wings Mahalanobis
distance = 1.51, t2 = 45.4, P = 0.29; hind wings
Mahalanobis distance = 1.74, t2 = 60.7, P≤0.01),
Orilla de Maule and Yerbas Buenas (fore wings
Mahalanobis distance = 1.36, t2 = 37.1, P = 0.52;
hind wings Mahalanobis distance = 1.69, t2 = 57.2,
P≤0.01). Finally, discriminant function analysis
showed non-signicant differences between host
plants (fore wings Mahalanobis distance = 1.33, t
2
= 52.7, P = 0.06; hind wings Mahalanobis distance
= 0.94, t2 = 26.4, P = 0.24).
Discussion
Our results support previous reports of sexual
dimorphism in body mass and wing morphology
in the codling moth (Schumacher et al., 1997a; Gu
et al., 2006), with females showing larger thorax,
abdomen and body mass than males. Larger body
size is related to higher detoxication capacity,
which confers resistance towards insecticides
(Reyes et al., 2004, 2015; Fuentes-Contreras et
al., 2007). Therefore, females with larger body
size have higher levels of insecticide resistance
than do males with a smaller body size (Varela
et al., 1993; Sauphanor et al., 2000; Reyes et al.,
2004, 2015; Fuentes-Contreras et al., 2007).
In our study, codling moth females have longer
(higher R), larger (higher S), and wider (lower
AR) wings than males. However, heavier females
with larger, longer and wider wings have a similar
wing loading (Pw) as males. The wing shape of
females is associated with slow and agile ight
in restricted space and dense vegetation, whereas
the smaller and more slender wings of males is
related to extensive ight in open spaces (Betts and
Wootton, 1998). The similar wing loading between
sexes is indicative of similar ight speeds (Betts
and Wootton, 1998). Wing geometric morphology
analyses consistently detected larger wings for
females, with females exhibiting broader wings
than males, as previously reported by Khaghaninia
et al. ( 2011a , b).
Differences in body mass and wing morphology
between sexes are indicative of different dispersal
capabilities. Regardless of sex, adult ight in
wind-tunnel experiments has shown a negative
correlation with body weight (Schumacher et al.,
1997a). However, no major differences in ight
capacity between males and females were found
in another study (Schumacher et al., 1997b). Flight
activity was related with the circadian rhythm,
age and mating status rather than sex (Schum-
acher et al., 1997b; Keil et al., 2001; Gu et al.,
2006). Additionally, ight activity was higher in
mated than virgin females and increased during
the egg-laying period; therefore, little dispersal
occurs before mating (Schumacher et al., 1997b).
Both sexes showed higher activity at dusk, with
males reaching ight activity peaks at a younger
age than females (Keil et al., 2001). Treatment
with the juvenile hormone mimic insecticide
fenoxycarb stimulated locomotor activity and
provoked a marked activity peak at dawn in
both virgin and mated females (Keil et al., 2001).
Therefore, morphological traits are important to
explain dispersal, and the physiological and life
history attributes are of major relevance (Roff
and Fairbairn, 2007).
Regardless of sex and host plant, adults from
Orilla de Maule were heavier and had higher Pw
than adults from Las Cruces and Yerbas Buenas.
However, no differences in R, S or AR were found
between locations. The geometric morphology
analyses revealed signicant differences in the
ciencia e investigación agraria402
Table 2. Mean ± SE wing length (R) (mm), area (S) (mm2), loading (Pw) (mg mm-2), and aspect ratio (AR) from males and females obt ained from different host plants and localities in the
Maule Region, Chile.
Mean ± SE wing length, area, loading and aspect ratio1
Male Female
Locality Host R (mm) S (mm2) Pw (mg mm-2) AR R (mm) S (mm2) Pw (mg mm-2) AR
Las Cruces Apple 7.3 ± 0.2 32.0 ± 1.5 0.129 ± 0.004 6.67 ± 0.07 8.0 ± 0.2 40.9 ± 2.2 0.135 ± 0.006 6.37 ± 0.10
Walnut 7.3 ± 0.1 32.5 ± 0.9 0.133 ±0.007 6.56 ± 0.06 7.6 ± 0.3 37.4 ± 2.9 0.138 ± 0.008 6.35 ± 0.11
Mean27.3 ± 0.2 32.3 ± 1.2 0.131 ± 0.006 b 6.62 ± 0.07 7.8 ± 0.2 a 39.1 ± 2.6 a 0.137 ± 0.007 b 6.36 ± 0.10 a
Orilla de Maule Apple 7.0 ± 0.1 29.5 ± 1.0 0.167 ± 0.010 6.58 ± 0.10 7.8 ± 0.2 37.6 ± 2.0 0.188 ± 0.020 6.50 ± 0.11
Walnut 7.1 ± 0.2 30.5 ± 1.2 0.173 ± 0.011 6.59 ± 0.14 8.1 ± 0.2 41.0 ± 2.0 0.183 ± 0.006 6.45 ± 0.08
Mean 7.0 ± 0.1 30.0 ± 1.1 0.170 ± 0.010 a 6.59 ± 0.12 7.9± 0.2 39.3 ± 2.0 0.186 ± 0.015 a 6.47 ± 0.09
Yerbas Buenas Apple 7.3 ± 0.2 32.5 ± 1.8 0.154 ± 0.009 6.54 ± 0.09 8.0 ± 0.2 40.8 ± 2.4 0.141 ± 0.09 6.31 ± 0.07
Walnut 7.5 ± 0.1 33.6 ± 1.6 0.131 ± 0.009 6.67 ± 0.09 8.0 ± 0.2 40.4 ± 1.9 0.162 ± 0.014 6.42 ± 0.07
Mean 7.4 ± 0.2 33.0 ± 1.7 0.142 ± 0.009 b 6.60 ± 0.09 8.0 ± 0.2 a 40.6 ± 2.1 a 0.152 ± 0.012 b 6.36 ± 0.07
Grand Mean37.2 ± 0.2 B 31.8 ± 1.4 B 0.148 ± 0.010 6.60 ± 0.09 A 7.9 ± 0.2 A 39.7 ± 2.2 A 0.158 ± 0.013 6.40 ± 0.09 B
1Sample size N = 10.
2Small letters indicate signi cant differences between localities in each column.
3Capital let ters indicate signicant dif ferences between sex columns.
403
VOLUME 42 Nº3 SEPTEMBER – DECEMBER 2015
shape of the fore and hind wings between locations,
which were accounted for by marginal differences
in the fore wings between Orilla de Maule and
Las Cruces and larger differences in the hind
wings from Yerbas Buenas in comparison with
Las Cruces and Orilla de Maule. Previous studies
on wing geometric morphology of codling moth
populations from different localities in North-
West Iran (Khaghaninia et al., 2011a,b) found
that abiotic conditions, such as wind velocity at
different altitudes, were associated with signicant
changes in wing size and shape. Slender and longer
wings were found in codling moth adults from
higher altitudes (Khaghaninia et al., 2011a , b).
All locations included in our study were in the
central valley of the Maule River, less than 50
km apart, at altitudes between 100 and 200 masl.
At the small geographic scale of our study, it is
less likely that abiotic factors explain the differ-
ences in body mass or wing shape. We propose
that biotic factors, such as host plant condition
and codling moth population density, which
might vary at smaller spatial scales, explain the
changes in body mass and wing size and shape
observed between locations. For instance, water
availability for home-grown trees could be higher
or the codling moth population density lower in
Orilla de Maule than in Las Cruces and Yerbas
Buenas, which could improve the availability of
fruits as resources for the development of the
codling moth and therefore allow a higher body
mass and wing size in adults from this location
in relation to others with lower fruit availability
or higher codling moth population density (Ferro
and Hardwood, 1973; Howell, 1991).
Previous studies detected behavioral differences
between codling moth from apple and walnut
trees in California (Cisneros and Barnes, 1974;
Phillips and Barnes, 1975). Because no inuence
of the host plant species on body mass or wing
morphology was found, our results did not sup-
port a phenotypic differentiation between apple
and walnut populations in the Maule Region of
central Chile. Walnut is often regarded as a sec-
ondary host for codling moth in comparison with
apple because of the high content of secondary
metabolites (e.g., juglone) that the walnut fruit
contains (Piskorski and Dorn, 2011). Effective
metabolism of juglone was found in codling moth
larvae feeding on walnut, although a longer devel-
opmental period and a male biased sex ratio were
observed when reared in this host plant (Piskorski
and Dorn, 2011). In our study, we used adults
obtained from apple and walnut trees; therefore,
we selected those individuals who successfully
developed on those host plants.
Our results conrm previous studies showing
differences in body mass and wing morphology
depending on codling moth sex and location
but did not nd differences between apple and
walnut as host plants. Small individuals from
home-grown trees should have high insecticide
susceptibility and dispersal capabilities. The
scenario of insecticide-susceptible adults mi-
grating to managed orchards has been proposed
as source-sink population dynamics that could
explain the low levels of insecticide resistance
found in codling moth in central Chile (Fuentes et
al., 2014). Further studies could evaluate whether
such differences based on sex and location in
body mass and wing morphology could affect
the dispersal of this species and subsequently
inuence its management through the use of
insecticides and mating disruption.
Acknowledgements
This work was funded by Fondo de Desarrollo
Cientíco y Tecnológico (FONDECYT) grant
1120374 to EFC and BL, and Programa de Atrac-
ción e Inserción de Capital Humano Avanzado
en la Academia (CONICYT-PAI) 7912010027
to MR.
ciencia e investigación agraria404
Resumen
F. Torres, M.A. Rodríguez, B. Lavandero y E. Fuentes-Contreras. 2015. Tamaño corporal
y morfometría geométrica de la polilla de la manzana (Lepidoptera: Tortricidae) según
sexo, localidad y planta hospedera en la Región del Maule, Chile. Cien. Inv. Agr. 42(3):
397-406. La polilla de la manzana, Cydia pomonella (L.) (Lepidoptera: Tortricidae), es la plaga
clave de manzanos y nogales alrededor del mundo. Entre otras variables, el manejo exitoso
de esta plaga depende de la dispersión de los adultos en la escala local. Se evaluó el peso
corporal y la morfología geométrica de las alas de hembras y machos adultos de la polilla de la
manzana, Cydia pomonella (L.) (Lepidoptera: Tortricidae), provenientes de manzano y nogal
en tres localidades de la Región del Maule, Chile. A partir de larvas en diapausa recolectadas
en el campo se obtuvieron adultos de la polilla de la manzana en laboratorio. Los adultos recién
emergidos fueron muertos y se calculó el peso seco total, peso del tórax y peso del abdomen.
Las alas fueron aclaradas y montadas para su análisis morfométrico, el cual incluyó 15 hitos
para las alas delanteras y once para las alas posteriores, respectivamente, incluyendo puntos
de unión de las venas y puntos de unión vena/margen. Además, se evaluó el largo, área, carga
alar y razón de aspecto de las alas. Como se ha reportado previamente, encontramos que las
hembras mostraron mayor peso de tórax, abdomen y cuerpo completo, con alas más largas,
grandes y anchas que los machos. Sin embargo, tales diferencias no resultaron en diferencias
de la carga alar entre sexos. El análisis de morfometría geométrica también conrmó un
dimorsmo sexual en el tamaño y forma de las alas anteriores y posteriores. Se encontraron
diferencias signicativas en el peso corporal y la carga alar entre localidades, con diferencias
en la morfología geométrica de la forma, pero no del tamaño en las alas anteriores y posteriores.
La planta hospedera (manzano y nogal) no inuenció ninguna de las variables de peso corporal,
tamaño o forma de las alas analizadas en los adultos de la polilla de la manzana. Se discuten
las posibles consecuencias de las diferencias en peso corporal y morfología alar según sexo y
localidad sobre la dispersión y manejo de esta plaga primaria.
Palabras clave: Carga alar, Cydia pomonella, hito, manzano, MorphoJ, nogal, razón de
aspecto.
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... Codling moth females are only slightly larger than males, and the two sexes have no distinguishing morphological characters without requiring a physical manipulation of the moth to observe the genitalia and the underside of the forewings. 38 It is also impossible to accurately sex moths from examining the screen images. The development of bisexual lures and the need to improve both action thresholds and phenology models based on female counts could be considered as serious limitations for the future adoption of smart traps. ...
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... The potential introduction of codling moth populations from different host plants species should have resulted in a more consistent genetic differentiation related to the host plants between the different localities. Furthermore, body mass, wing size, and shape variables studies performed with geometric morphology techniques did not show significant differences between the body size or wing morphology of the codling moths obtained from different host-plant species (apple versus walnut), further supporting the lack of host-plant strains of this species in the Maule Region of Chile [56]. ...
... The potential introduction of codling moth populations from different host plants species should have resulted in a more consistent genetic differentiation related to the host plants between the different localities. Furthermore, body mass, wing size, and shape variables studies performed with geometric morphology techniques did not show significant differences between the body size or wing morphology of the codling moths obtained from different host-plant species (apple versus walnut), further supporting the lack of hostplant strains of this species in the Maule Region of Chile [56]. ...
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... In CM, the effect of resistance on wing shape and size changes has not been examined. However, there have been several authors who have investigated how CM wing size, shape, and wing geometry are influenced by geography, wing speed, and elevation (e.g., CM from Iran [33,34]) and sex, location, and host plant (e.g., CM from Chile [35]). Studies on CM and insecticide resistance have shown that larger females are more resistant than smaller males [19,36,37]. ...
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... Immigration of susceptible individuals has been suggested as an important mechanism of insecticide resistance mitigation [27,35,57], and the preservation of susceptible individuals in refuges, within productive growing areas, could also be a determinant factor in delaying the increase in the proportion of insecticide-resistant individuals [58][59][60]. Moreover, differences in body mass and wing morphology between sexes are indicative of different dispersal capabilities [61] and also of different detoxification insecticide capabilit ies [4,17,57,62]. Therefore, our results ...
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