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Revista Brasileira de Entomologia 56(4): 492–498, dezembro, 2012
Regardless of the cropping systems, local conditions, and
the cultivated variety, cotton plants can be infested by sev-
eral insect and mite species. Among the defoliator insects,
the American cotton leafworm, Alabama argillacea (Hübner)
(Lepidoptera, Noctuidae), is of common occurrence across
all cotton growing areas in Brazil. Recently, Anomis impasta
(Guenée) (= Anomis doctorium), has been collected in ex-
perimental cotton fields localized in Remigio (PB), Paudalho
and Surubim (PE), and in grower areas placed at Frei
Miguelinho (PE). This noctuid species is remarkably similar
to A. argillacea concerning the egg morphology, early larval
instars, pupal stage and feeding behavior. The only published
record of the occurrence of A. impasta in Brazil was made by
Guenée using specimens from Bonito, Pernambuco (Dyar
1913). Given the resemblance, both morphological and be-
havioral, with a common and well known cotton pest, A.
argillacea, the occurrence of A. impasta in our cotton fields,
at least in the Semiarid region, might have been masked. In
fact, Lima (1949) already mentioned the similarity of Anomis
texana (Riley) with A. argillacea, and that the former spe-
cies was an important pest of cotton in Peru.
Cotton has moved considerably across Brazil over the past
two decades. Large areas of cotton were located in the Arid
and Semiarid regions of the Northeast until 1980’s. During
The lesser cotton leafworm, Anomis impasta (Guenée) (Lepidoptera,
Noctuidae), in cotton
Roberta L. dos Santos1, Jorge B. Torres1,3, Itillio V. A. F. Pontes1, Eduardo M. Barros1 & Cristina S. Bastos
1Departamento de Agronomia-Entomologia, Universidade Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros s/n, Dois Irmãos,
52171–900 Recife-PE, Brazil. robertaleme2@uol.com.br, jtorres@depa.ufrpe.br, itilliopontes@hotmail.com
2Instituto Central de Ciências Ala Sul, Faculdade de Agronomia e Medicina Veterinária, Universidade de Brasília, 70910–900 Brasília-DF, Brazil.
cschetino@unb.br
3Corresponding author: jtorres@depa.ufrpe.br
ABSTRACT. The lesser cotton leafworm, Anomis impasta (Guenée) (Lepidoptera, Noctuidae) in cotton. Anomis impasta (Guenée)
is a species that shows remarkable morphological and behavioral similarities with the cotton leafworm Alabama argillacea (Hübner).
During two growing cotton seasons, A. impasta was observed feeding on leaves and flower bracts of cotton and monitored. Further-
more, a study was conducted under laboratory conditions to generate biological information about this species with larvae feeding
cotton squares and leaves. Larvae fed on cotton squares exhibited delayed development (18.5 ± 0.18 days) and lower pupal weight
(140.8 ± 2.26 mg) compared to larvae fed on cotton leaves (14.0 ± 0.07 days and 169.3 ± 2.06 mg). Thus, one generation cycle of
A. impasta was obtained by feeding the larvae with cotton leaves. The mean (minimum-maximum) values for the duration of eggs,
larvae and pupae were: 3.0 (3–4), 14.8 (14–18), and 9.7 (7–14) days, respectively. The viability of the eggs, larvae, and pupae were
43.7, 98.3, and 94.7%, respectively. Females lived on average 25.2 days (ranging from 15 to 37 days) and produced 869 eggs (from
4 to 1,866 eggs). The successful development and reproduction of A. impasta on cotton, especially, on the cotton leaves, suggest the
potential of this species to reach a pest status in cotton. The similarities with A. argillacea, as discussed in this study, can be one of
the reasons for low reference to A. impasta in the field. Therefore, the information provided here will allow researchers and growers
to distinguish these two cotton defoliators.
KEYWORDS. Biology; cotton pest; intercropping; Noctuidae.
RESUMO. O curuquerê, Anomis impasta (Guenée) (Lepidoptera, Noctuidae) em algodoeiro. Anomis impasta (Guenée) é uma
espécie que apresenta morfologia e comportamento muito similar ao curuquerê-do-algodoeiro, Alabama argillacea (Hübner). Du-
rante duas safras de algodão, foi monitorada a alimentação de A. impasta em folhas e brácteas da cultura. Assim, este estudo foi
conduzido para gerar informações biológicas sobre a espécie. As larvas foram criadas em folhas de algodão e botões florais (brácteas
+ botão floral), partes em que as lagartas foram comumente encontradas em campo. Larvas criadas com botão floral apresentaram
maior período larval (18,5 ± 0,18 dias) e menor peso pupal (140,8 ± 2,26 mg) em comparação às larvas criadas apenas com folhas
(14,0 ± 0,07 dias e 169,3 ± 2,06 mg). Assim, uma geração de A. impasta foi obtida alimentando-se as larvas com folhas de algodão.
A média (variação) de duração para a fase de ovo, larva e pupa foi de 3,0 (3 a 4), 14,8 (14 a 18) e 9,7 (7 a 14) dias, respectivamente.
A viabilidade para ovos, larva e pupa foi de 43,7; 98,3 e 94,7%, respectivamente. As fêmeas viveram em média 25,2 dias (15 a 37)
e produziram 869 ovos (4 a 1866). O desenvolvimento e reprodução de A. impasta em algodoeiro, em especial quando as lagartas
desenvolvem-se sobre folhas, fornecem indícios do seu potencial em atingir condição de praga na cultura. A semelhança com a
espécie A. argillacea, como apresentado neste estudo, pode ser uma das razões de sua baixa constatação de A. impasta em campo.
Portanto, acredita-se que as informações geradas com este estudo auxiliem pesquisadores e produtores na identificação dessas duas
espécies desfolhadoras do algodoeiro.
PALAVRAS-CHAVE. Biologia; Noctuidae; policultivo; pragas do algodoeiro.
493The lesser cotton leafworm, Anomis impasta (Guenée) in cotton
Revista Brasileira de Entomologia 56(4): 492–498, dezembro, 2012
the mid 1980’s, the crop moved from those areas to the me-
ridional part of Brazil, concentrating on Paraná and São Paulo
States. In the late 1990’s, large areas of cotton were estab-
lished in the Cerrado’s biome spreading out around the West,
Central and Northeast regions of Brazil, stretching out, later
on, toward the Northwest and North regions areas (Fontes et
al. 2006; Freire 2007). This change in the distribution of the
cotton growing areas has exposed the crop to a diversified
arthropod fauna (Torres 2008). In addition to the usual her-
bivores commonly associated with the crop, new species of
insects have been reported damaging cotton. The adoption
of new varieties and cropping systems such as non-tillage
and doubling cropping, the cultivation of large areas next to
other major crops, and the intensive use of pesticides, can be
cited as the possible causes for secondary pests outbreaks,
and may account for the emergence of new cotton pests (Diez-
Rodriguez & Omoto 2001; Torres 2008; Nagoshi 2009;
Barros et al. 2010a; b).
Despite the tendency of increasing areas cultivated with
cotton within Brazil, the semiarid region has been reducing
the cultivation of cotton over the past decades. In addition, it
seems that the way of cultivating cotton has not changed much
over the years, mainly while comparing these areas with those
grown in the Cerrado’s Biome. In the Semiarid of Northeast,
cotton is cultivated by small growers, where the predomi-
nant techniques adopted are extractives, e.g., very limited
inputs are used for fertilization or pest management purposes
(Barros & Torres 2010). Therefore, studies on the entomo-
fauna of cotton in the Semiarid of northeast Brazil are scarce.
Considering the recent past, only species of mealybugs have
been reported to cause loss in cotton production in the Semi-
arid that was not common in the previous pest records (Bastos
et al. 2007; Torres et al. 2011). Lately, this species has been
also reported in the Cerrado’s areas of Bahia, Goiás, and Mato
Grosso (J. B. Torres), major areas of cotton production in
Brazil.
The genus Anomis comprehends 201 species and subspe-
cies (Zipecodezoo 2010) with several species using
Malvaceae (e.g. cotton and okra) and Solanaceae (e.g. to-
mato) as hosts (CABI 2010). Anomis flava (Fabr.) and Anomis
fulvida Guenée have been reported as pest of cotton in Aus-
tralia, Philippines, India, and Madagascar (Bishop et al. 1978;
Ferino et al. 1981; Kuklinski 2000), while Anomis texana
(Riley) is a pest of cotton in various countries of the Ameri-
can continent including Chile, Guatemala, Mexico, Peru, and
United States (Lima 1949). Lima (1949) while describing A.
argillacea stressed the high degree of similarities found be-
tween A. texana and A. argillacea and stated that A. texana is
an important pest of cotton in Peru. According to Deutscher
et al. (1999), unsprayed cotton fields in Australia have as
much as 80% of defoliation under infestation of A. flava.
However, infestations are uncommon in fields where sprays
are applied to control bollworms. Furthermore, Anomis
sabulifera (Guenée) has been an important pest of jute in
India, requiring intensive control efforts (Tripathi & Ram
1972; Hat & Basak 2000; Yadav 2010). In Brazil, Anomis
illita Guenée was cited occurring in Itaperuna, RJ, feeding
upon Urena lobata (Malvaceae) (Lima 1949).
Considering the lack of information on A. impasta and
the potential problems that may arise from the attack and
misidentification of this insect in cotton plants, this study
aimed to report the dynamics of A. impasta infesting cotton
from a Semiarid area of Brazil. In addition, this contribution
also aims to generate data on the biology of this species feed-
ing on cotton.
MATERIAL AND METHODS
Field description and sampling procedure. The occur-
rence of A. impasta was noticed during two cotton seasons,
2008 and 2009, in field plots set up in Remigio, PB,
08°01’46.5"S and 34°57’28.7"W. The occurrence and popu-
lation densities of the species were verified and monitored
simultaneously to an experiment in which the influence of
intercropping local crops including cotton (Gossypium
hirsutum cv. BRS Rubi), cowpea (Vigna unguiculata L.
(Walp.)), corn (Zea mays L.), peanut (Arachis hypogaea L.),
and sesame (Sesamum indicum L.) was under investigation.
The planting dates were the 10th and 30th May in 2008 and
2009, respectively. The experiment was set up as a random-
ized block design with four plots (replications) and three treat-
ments: cotton cultivated in monoculture (i); local grower
design consisting of cotton cultivated intercropped with cow-
pea and corn (ii); and a system consisting of cotton inter-
cropped with sesame and peanut (iii). The intercropping
system adopted consisted of three different crops cultivated
simultaneously. The intercropping design adopted was that
used by local growers, which consisted of three lines of each
crop. Each experimental plot consisted of 18 crop lines with
six lines for each crop species. Each line was 16m long. Three
lines of sorghum surrounded the whole experimental field
as a way to separate/isolate each experimental plot. Besides
randomizing the plots within the whole experimental area,
the group of three lines of each plant species was also ran-
domized within the each plot. The row and within row spac-
ing adopted followed the local growers’ practice: cotton
(1.1x0.4 m), corn (1.0x1.0 m), sesame (0.8x0.8 m), cowpea
and peanut (0.5x0.5 m). Thinning and weed control were
carried out by hand. No external inputs were adopted such as
pesticides or fertilizers.
A. impasta was sampled by randomly inspecting 10 cot-
ton plants per plot. For each plant, the whole plant was in-
spected for larvae and pre-pupae. Since only the larvae and
pre-pupae could be safely differentiated in the field, we did
not use eggs and pupae in this study. Neonate larvae, when
not clearly separated apart from A. argillacea in the field,
were collected and reared up to the second or third instar
allowing a correct identification. Samplings were carried out
at 10 to 12 days intervals, from June 25 to October 11 in
2008 and from June 12 to October 16 in 2009, with 10 sam-
pling dates. The total number of larvae found in a cotton
plant was averaged from the 10 plants evaluated per plot on
494 Santos et al.
Revista Brasileira de Entomologia 56(4): 492–498, dezembro, 2012
each sampling date to produce the mean value of replication
(plot) per treatment. In addition to the species occurrence
report, the abundance of A. impasta larvae per treatment was
submitted to one-way repeated measure analysis of variance,
using the sampling dates within plots as the repeated mea-
sures (between subjects) and the treatments and abundance
over time as the factors under analysis (within subjects). These
analyses were carried out using PROC MIXED of SAS (SAS
Institute 2001).
Development of A. impasta fed with cotton squares or
leaves. A colony of A. impasta was set up at the Biological
Control Laboratory of the Universidade Federal Rural de
Pernambuco (UFRPE) from larvae and pupae collected in
cotton fields cultivated with the variety BRS Rubi and in the
experimental plots, both located in Remigio, PB, Brazil
(08°01’46.5"S and 34°57’28.7"W).
The insects were kept at 26 ± 2°C, 60–80% relative hu-
midity, and 12 h photophase following the methods used to
rear de American cotton leafworm, A. argillacea. Briefly,
larvae were reared up to pupal stage, and then they were dis-
lodged from the leaves and transferred to adult cages. Adult
cage consisted of a cylindrical PVC tube (17cm width and
22 cm tall), placed over a plastic plate of 20cm diameter lined
with paper towel. The top of the cages was closed with
organdie fabric fixed with an elastic ribbon. Adults were fed
with 10% honey solutions (honey: water) applied to moist-
ened cotton pads inserted inside plastic caps and placed in
the bottom of the cages. Cotton terminals were offered as
egg laying substrate. Cotton terminals were cut from the plant,
placed in water, and cut again to prevent cavitations. Each
stem was placed into a 100 mL water filled vial. To maintain
the stock colony, eggs laid on the plant terminals were col-
lected together with the whole structure every day, when the
terminals were also replaced for a new one. To set up the
biological observations, plant terminals were offered in the
evening and replaced in the morning. This guarantees that
the eggs used in the experiment were less than 12h-old. There-
after, leaves containing the eggs were transferred to Petri
dishes until larval emergence. The Petri dishes containing
the eggs were stored in climatic chamber regulated to 25°C
and 12h of photophase. The study was initiated with eggs of
the third generation of the colony in the laboratory. Newly
hatched larvae were fed fresh cotton leaves harvested from
cotton variety Acala 90.
During field sampling procedures, young larvae were
observed while feeding on cotton leaves. Large larvae and
pre-pupae were located between bracts and flowers or boll
and damaged both flower bracts and bolls. Based on these
field observations, two treatments were set up: larvae feed-
ing on whole flower square (bracts and bud); and larvae feed-
ing only on fully expanded leaves from the plant terminals.
The cotton variety used was Acala 90.
The performance of A. impasta larvae feeding on squares
and expanded cotton leaves from plant terminals was evalu-
ated based on the duration and survival of larval and pupal
stages and the weight of 24h-old pupae. To obtain these pa-
rameters, newly hatched larvae (< 12h-old) were transferred
to plastic containers of 80mL-volume (Cral Artigos para
Laboratório Ltda). Tiny perforations were made throughout
the container caps using a no. 1 entomological pin to allow
ventilation inside the containers. The observations initiated
with 90 neonate larvae per treatment. A rate of three larvae
per rearing containers was maintained during the first three
days of the larval stage. Each container represented a repli-
cation. After three days, the food was replaced and the sur-
viving larvae were individually reared. Observations on the
development and survival were daily performed together with
food replacement and cage cleaning operations. Developmen-
tal times and survival of larvae and pupae, and weight of
pupae were tested for normality (Kolmogorov D: normal test)
and homogeneity of variance (Bartlett’s test), and square root
(x + 0.5) or arsine square root (survival/100) transformed
every time the data failed to fulfill one of the ANOVA’s as-
sumptions. However, untransformed means are presented.
One-way analysis of variance (ANOVA) was performed us-
ing the PROC GLM of SAS (SAS Institute 2001), and the
results from the F-test were used to infer about the means of
treatments.
Development and reproduction of A. impasta. Based
on previous experimental results, the best performance of
the larva and pupa of A. impasta was obtained with the lar-
vae feeding on cotton leaves. Thus, this part of the study aimed
at evaluating the development and reproduction of A. impasta
while feeding on cotton leaves of the variety Acala 90.
Cotton leaves were overnight exposed to the moths as an
egg laying site. Then, leaves containing eggs less than 12h-
old were cut into pieces containing three eggs each. Forty
replications consisting of three eggs each were monitored.
The pieces of leaves containing the eggs were stored in plas-
tic containers of 80mL with finely perforated lids to allow
ventilation inside the containers. The containers holding the
eggs were maintained in climatic chamber regulated to 25 ±
1°C, 12h of photophase and relative humidity varying from
60 to 70% until the emergence of the larvae. After larval
emergence, 60 larvae were individually reared per container
to evaluate the developmental period and survival. The food
offered to the larvae was pieces of cotton leaves picked from
the upper portion of cotton plants of the variety Acala 90.
Food replacement took place at daily intervals starting with
larval emergence and extending until pupation. During diet’s
replacement the containers were cleaned, eliminating feces
and remaining pieces of food. The presence of head capsule
was used to determine the day of the molt, and later to deter-
mine the number of instars that the larvae went through. Some
larvae were reared separately under the same conditions to
allow registration of the larval stages through measurements
and pictures. Measurements were made using a micrometer
scale (0.01 mm), attached to the ocular of a light microscope
(10–40, Motic™, São Paulo, Brazil).
By recording the day of pupation, it was possible to de-
termine the duration of each larval instar and the viability of
the each instar. The body size of pupae based on their weight
495The lesser cotton leafworm, Anomis impasta (Guenée) in cotton
Revista Brasileira de Entomologia 56(4): 492–498, dezembro, 2012
was taken on 24h-old pupa. The pupae were reared in the
same rearing containers of the larvae until adult’s emergence.
Two days prior to adult’s emergence, one male and one fe-
male pupae were transferred to adult rearing cages that con-
sisted of PVC tubes of 10cm diameter and 17cm tall. Twenty
adults (= replications) were monitored daily to evaluate egg
production and longevity of females. Cotton pads moistened
in 10% honey solution (honey: water) fixed inside plastic
caps were placed in the bottom of the cages for adults feed-
ing. To enhance oviposition and to facilitate egg counting,
young cotton leaves were harvested, had its petiole inside
vials containing water, and offered as substrate for the fe-
male to lay eggs. Cotton leaves were replaced daily and the
cages also had the wall inspected for eggs. After counting
the eggs laid on the cotton leaves using a bench 10x-magni-
fication lent, the cotton leaves containing the eggs were main-
tained in Petri dishes sealed with PVC film until larva
emergence. Egg viability was determined based on the num-
ber of hatching larvae. Further, the age of first oviposition,
period of egg production and female longevity were also
determined. The female adult size based on wingspan (the
largest distance between the two wings ends) was also taken
from those females that exhibited no damage on the wings at
day of death (n = 7 males and 6 females). The data were then
averaged and presented with minimum and maximum value
range.
RESULTS AND DISCUSSION
Occurrence of A. impasta in cotton. The lesser cotton
leafworm, A. impasta, was present in all three experimental
locations during the two years of study. The distances from
these experimental locations (Paudalho and Surubim, PE; and
Remigio, PB) to the grower field in Frei Miguelinho, PE,
varied from 126 to 230Km.
Intercropping cotton with any of the tested crops did not
shape the infestation of A. impasta larvae in cotton during the
seasons of 2008 (F2, 18 = 2.11, P = 0.2023) and 2009 (F2, 18 =
1.00, P = 0.4210) (Fig. 1). The seasonal means of A. impasta
larvae per cotton plant across the 10 sampling dates in 2008
were 0.56 ± 0.09, 0.34 ± 0.06 and 0.41 ± 0.05 for cotton mo-
noculture, cotton intercropped with cowpea and corn, and cot-
ton intercropped with peanut and sesame, respectively. The
density of larvae per plant in 2009 was quite similar to the
density found in the previous year: 0.46 ± 0.08, 0.52 ± 0.08,
and 0.47 ± 0.08 larvae per plant of cotton monoculture, cotton
intercropped with cowpea and corn, and cotton intercropped
with peanut, respectively. The average number of larvae per
plant, however, varied throughout the cotton growing season
of 2008 (F9, 27 = 13.43, P < 0.0001) and 2009 (F9, 27 = 23.60, P
< 0.0001). During 2008, the highest densities of larvae per
cotton plant were found in the evaluations carried out on Sep-
tember 3 and 13. In 2009, the greatest densities of larvae per
plant were found in the evaluations made at July 20 and Au-
gust 2 (Fig. 1). Although the high occurrence of larvae took
place during mid-late season over a100 days-old crop, larvae
of A. impasta was found earlier (second and first evaluations
of 2008 and 2009, respectively), when the crop was around
30-days old. In 2008 and 2009, the mean densities were over
1.0 and 1.5 larvae per plant, during the periods of higher oc-
currence. Despite the observed infestation, severe plant defo-
liation was not observed. According to Ferino (1981), 5 to 6
mature larvae of A. flava per plant were required to cause de-
foliation of approximately 60%. These authors also reported
that A. flava larvae were heavily parasitized and preyed upon
in the field, which probably occurred in our fields considering
that no pesticides were used at any time and the high diversity
of predators observed (data not showed here).
Eggs and neonate larvae of A. impasta were treated as A.
argillacea at beginning of this study, since these two species
share similar characteristics at these stages (Fig. 2). How-
ever, later instar larvae of A. impasta exhibited behavior of
lodging in the fruiting structures between the bracts and the
flower squares, flowers and bolls. At that stage, A. argillacea
stays predominantly on the leaves scattered throughout the
plant canopy. In addition, the morphology is notably differ-
ent from A. argillacea for older larvae.
Development of A. impasta fed cotton squares or leaves.
Larvae of A. impasta fed with cotton squares (bracts + buds)
delayed development on average for 4.5 days (18.5 ± 0.18
days) compared to larvae fed with cotton leaves (14.0 ± 0.07
days) (F1, 70 = 719.20, P < 0.0001). Furthermore, larvae fed
Fig. 1. Seasonal means (+SE) of Anomis impasta larvae per plant of cotton
(variety BRS Rubi). Remigio, PB. Seasons 2008 and 2009.
496 Santos et al.
Revista Brasileira de Entomologia 56(4): 492–498, dezembro, 2012
with cotton leaves produced larger pupae (169.3 ± 2.06 mg)
compared to pupae originated from larvae fed with flower
squares (140.8 ± 2.26 mg) (F1, 70 = 65.03, P < 0.0001). In
fact, larvae did not injure flower squares, where only scars
were observed. The larvae fed mostly on the flower bracts
when offered only flower squares and bracts.
Development and reproduction of A. impasta. The eggs
of A. impasta are light blue-green when first laid, becoming
brownish-yellow close to hatching. The eggs are almost
spherical with a slightly flattened top with an average of 0.69
mm in diameter (n = 15 eggs) (Fig. 2). Like most noctuids,
the egg has a series of ridges projected upwards, hardly no-
ticeable at the top near the micropyle (Torres & Ruberson
2006). In the field, the eggs are laid individually, scattered
over the plant leaves, bracts and pinhead structures. Under
laboratory conditions (on rearing cages) cluster of eggs were
observed, especially on the pinhead structures.
Larvae of first, second and third instars are slender and
with greenish-yellow coloration (Fig. 2). They feed by scrap-
ing the leaves of the plant terminals and bracts, similarly to
the common American cotton leafworm. As the third and fourth
instar larvae increase in size, and start to have dark spots at the
Fig. 2. Developmental stages of Anomis impasta – eggs, first (I) and second instar larva (II). Green (V.a), reddish-purple (V.b), and dark fifth instar lar vae
(V.c); green (VI.a) and reddish-purple (VI.b) sixth instar prepupa larvae. Pupa and adult female (J.B. Torres). Tips of entomological pin no. 000 indicate
size of eggs, first and second instar larvae.
497The lesser cotton leafworm, Anomis impasta (Guenée) in cotton
Revista Brasileira de Entomologia 56(4): 492–498, dezembro, 2012
base of the setae. These spots form two rows of setae on the
dorsum with two pairs of setae per body segment. The spots
are more evident in fourth instar larvae and also in fifth instar
larvae from green populations. Coloration of the larvae might
change dramatically, from fifth to sixth instar (Fig. 2). Larvae
in the fifth instar can be differentiated into two populations
with predominance of green or black coloration in the dorsum
as observed for several species of noctuids. In our study, all
fifth instar larvae observed in the field were green-colored.
However, under laboratory conditions, color changed to dark-
brown in the dorsum at fifth instar and reddish-purple at sixth
instar (Fig. 2). In this laboratory study, only 29.8% of the lar-
vae (17 out of 57 larvae) retained the green coloration in the
fifth instar, while the remaining larvae changed color to dark-
brown or reddish-purple. Furthermore, 100% of those larvae
molting within a sixth instar exhibited the reddish-purple col-
oration, similar to all prepupae found out in the field. Despite
the color, both green and dark-brown fifth and sixth instar
larvae exhibited a characteristic pattern of inverted white bands
around the setae (Fig. 2 V.a to VI.a). There are several hypoth-
eses related to the polymorphism variation in noctuid larvae
(Applebaum & Heifetz 1999). The density-dependent phase,
in which individuals reared at high densities become heavily
melanized during the later larval instars, is one hypothesis
commonly reported. The high-density phase is also associated
with differences in behavior and developmental time
(Simmonds & Blaney 1986). Larvae reared in isolation typi-
cally exhibit green coloration. This might explains the pre-
dominance of the green population of A. impasta surveyed in
the field, while they were predominantly dark in crowded rear-
ing laboratory conditions. Additional hypotheses also suggests
that individuals reared solitarily might have melanized cuticles
and might be related to hormonal activities as sex pheromone
production (Matsumoto et al. 1990), diet (Fescemyer &
Erlandson 1993), defense against parasitism (Kunimi &
Yamada 1990), and diseases (Wilson et al. 2001). Diet affects
the degree of dark body color of gregarious Anticarsia
gemmatalis Hübner larvae, but it does not influence green
coloration in solitarious individuals (Fescemyer & Erlandson
1993). Therefore, several hypotheses substantiate the polymor-
phism observed in the noctuid larvae. However, the double
polymorphism exhibited by A. impasta mature larvae (Fig. 2
V–VI) that includes changes from green to dark and green to
reddish-purple is uncommon and should be explored for an
explanation.
The larvae grow, on average, from 3mm to 24mm from
first to the sixth instar. A gain of about 5.67 mm is obtained
just from the fifth to the sixth instar (Table I). The pupa of A.
impasta is quite similar to that of A. argillacea (Fig. 2). They
are found in sparse cocoon between bracts and bolls or in
curled up leaves. There was no statistical difference in size
between male and female pupae (Table I). Adult males and
females are also of similar size with wingspan ranging from
30 to 34 mm (Table I). Adult forewings are pale whitish brown
to darker pale with one pair of darker spots sparse on each
wing (Fig. 2). Hind wings are light pale with white borders.
The complete life cycle of A. impasta fed cotton leaves
of the variety Acala 90 comprised an average of 27.5 days
(95% confidence interval ranging from 26 to 31 days) (Table
II). Larval development occurred predominantly through five
instars, but 30% of the larvae exhibited an extra sixth instar
under rearing conditions. The larval viability was 98.3%. The
average weight of 24h-old pupae was 189.3mg (ranging from
164.1 to 221.8 mg) for female pupae and 188.3mg (ranging
from 128.4 to 215.9 mg) for male pupae. The adult emer-
gence was 94.7% with 53% of female adults. Female adults
lived on average 25.2 days (from 15 to 37 days).
Table I. Mean size (mm) (minimum-maximum) of Anomis impasta developmental stages fed with cotton leaves of the variety Acala 90. Temp.: 25 ± 1°C,
photophase 12 h, and R.H. of 65-80%.
Eggs Larvae Pupae Adults
I II III IV V VI Female Male Female Male
0.69
(0.65–0.75)
3.53
(3–4)
4.77
(4.5–5)
7.64
(7–8)
9.50
(8.5–11)
16.50
(15–19)
22.17
(20–24)
14.8
(14–16)
15.1
(14–17)
32.7
(32–34)
32.8
(30–34)
Table II. Mean duration (minimum-maximum) of the developmental stages
of Anomis impasta fed with cotton leaves of the variety Acala 90. Temp.:
25 ± 1°C, photophase 12h, and R.H. of 65–80%.
Eggs Larvae / instars Pupae Egg to adult
I II III IV V VI
3.0
(3–4)
3.1
(3–4)
1.3
(1–2)
2.6
(2–3)
2.1
(2–3)
2.1
(2–3)
5.0
(2–6)
9.7
(7–14)
27.5
(26–31)
From the 20 paired females used to evaluate adult sur-
vival and reproduction, three females did not lay eggs. From
the remaining 17 females, seven females did not produce
viable eggs. Considering all females monitored, it was yielded
an average of 577.2 eggs per female (from 0 to 1,866 eggs)
with 25.7% of the eggs hatching (from 0 to 78.8%). The av-
erage egg production among the females laying viable eggs
(n = 10 females) was 869 eggs per female (from 4 to 1,866
eggs) with 43.7% of egg hatching (from 3.2 to 78.8%). This
large variability in egg production and egg viability, includ-
ing females not laying eggs, can be a result of the various
factors that the insects are subjected when brought from the
wild to controlled conditions, including food quality, rearing
techniques and laboratory conditions. Besides the record
made by Dyar (1913) for A. impasta in Brazil, no data is
available for this species regarding its distribution, behav-
ioral traits, development, or reproduction. Thus, our study
provides the first data reported for this species. We hope that
this would provide the bases for further studies. In addition,
498 Santos et al.
Revista Brasileira de Entomologia 56(4): 492–498, dezembro, 2012
information about co-specific species, such as A. flava and
A. texana, is scarce, even when they happen to be of eco-
nomic importance as it is the case for the two previously
mentioned, which gives extra relevance to our findings.
Based on the lack of data for A. impasta in Brazil, two
hypotheses can be raised: First, A. impasta has sporadic oc-
currence due to the close host range to cotton, in which cul-
tivated area has reduced significantly in the Semiarid. The
monophagy condition is a reasonable explanation consider-
ing that most species of the group feed on malvaceous plants.
Second, the occurrence of the species is masked due to traits
that are shared with A. argillacea, a more important species.
Therefore, this species goes unnoticed when occurring in the
cotton fields with the population been kept under control by
the application of the insecticides aimed at controlling other
species, as it was found in Australia for A. flava and boll-
worms (Deutscher et al. 1999).
ACKNOWLEDGEMENTS
This research was sponsored by REDALGO-FINEP, CNPq,
and FACEPE. We thank Adriano Giorgi (UFRPE) for signifi-
cant comments and suggestions which greatly improved the
paper; and Dr. Victor Becker for the species identification.
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Received 25/11/2011; accepted 14/11/2012
Editor: Paulo Roberto Valle da Silva Pereira
