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Morphology, Genetics and Biology of Pterochloroides persicae Cholodkovsky (Hemiptera: Lachninae) and Their Effect on Pauesia antennata Mukerji (Hymenoptera: Aphidinae) Behaviour

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Pauesia antennata Mukerji is a specific parasitoid of the brown peach aphid Pterochloroides persicae Cholodkovsky which causes severe damage on almond and peach in Tunisia. To control this pest, P. antennata was collected from Iran, introduced to Tunisia in 2011 and some of their biological parameters were studied in laboratory conditions. Therefore, in orchard, aphid population and sites/zones of Tunisia and aphid behaviour impact on the parasitoid have not been studied. Morphometric measurements, molecular analysis of P. persicae specimens collected from two Tunisian sites [(Akouda-Sousse (Site 1), Sfax (Site 2)] were studied and compared and aphid behaviour versus P. antennata was followed. Results demonstrated a significant difference of four morphological characters (body length, body width, total antennal length, hind femora length). Molecular analysis showed two haplotypes corresponding to the sites. For biological analysis, larval longevities were 14.3 ± 1.52 and 12.6 ± 2.08 days for Site 1 and Site 2, respectively. Fecundities were 20.2 ± 13.57 and 12.3 ± 11.06 larvae/day corresponding to Sites 1 and 2, respectively. A relationship between P. persicae specimens and behaviour versus P. antennata were explained.
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Morphology, genetics and biology of Pterochloroides persicae Cholodkovsky
(Hemiptera: Lachninae) and their effect on Pauesia antennata Mukerji
(Hymenoptera: Aphidinae) behaviour
R.B. Adouani1*§, L. Mdellel1, M.B.H. Kamel1& D.T. Martinez2
1U.R: Cultures Maraichères Conventionnelles et Biologiques UR13AGR03, Institut Supérieur
Agronomique Chott Mariem, Université de Sousse, Tunisia
2Genetics Department, Institute for Integrative Systems Biology, University of Valencia, Spain
Pauesia antennata Mukerji is a specific parasitoid of the brown peach aphid Pterochloroides
persicae Cholodkovsky which causes severe damage on almond and peach in Tunisia. To
control this pest, P.antennata was collected from Iran, introduced to Tunisia in 2011 and some
of their biological parameters were studied in laboratory conditions. Therefore, in orchard,
aphid population and sites/zones of Tunisia and aphid behaviour impact on the parasitoid
have not been studied. Morphometric measurements, molecular analysis of P.persicae
specimens collected from two Tunisian sites [(Akouda-Sousse (Site 1), Sfax (Site 2)] were
studied and compared and aphid behaviour versus P.antennata was followed. Results
demonstrated a significant difference of four morphological characters (body length, body
width, total antennal length, hind femora length). Molecular analysis showed two
haplotypes corresponding to the sites. For biological analysis, larval longevities were 14.3 ±
1.52 and 12.6 ± 2.08 days for Site 1 and Site 2, respectively. Fecundities were 20.2 ± 13.57 and
12.3 ± 11.06 larvae/day corresponding to Sites 1 and 2, respectively. A relationship between
P.persicae specimens and behaviour versus P.antennata were explained.
Key words: parasitoid, aphid, morphometric and biological measures, haplotype, Tunisia.
INTRODUCTION
Pauesia antennata Mukerji (Hymenoptera: Braco-
nidae) is a specific parasitoid of the brown peach
aphid Pterochloroides persicae Cholodkovsky
(Hemiptera: Aphididae) (Cross & Poswal 1996;
Rakhshani et al. 2005). It is a solitary endopara-
sitoid originating from Southeast Asia (Kairo &
Poswal 1995). Its presence was limited to Pakistan,
Iran and Iraq (Rakhshani et al. 2005) despite wide
distribution of P.persicae which is found in temper-
ate regions such as Asia, southern Europe,
America, Italy, Spain, France, eastern Mediterra-
nean and North Africa (Bolchi Serini & Cravedi
1985; El Trigui & El Sherif 1989; Mendoza & Lacasa
1995; Kairo & Poswal 1995; Stoetzel & Miller 1998;
Rakshshani et al.2005; Blackman & Eastop 2006;
Ateyyat & Abu-Darwish 2009; Mdellel et al. 2011;
Hidalgo et al. 2013; Anses 2016). In Tunisia, the
brown peach aphid has been reported as a serious
pest of Prunus spp., especially peach and almond
trees (Jerraya 2003; Ben Halima Kamel & Ben
Hamouda (2004, 2005); Mdellel et al. 2011; Kamel
et al. 2012). Many biotic and abiotic factors can
cause changes on P.persicae growth and develop-
ment period (Müller et al. 2001; Thomas &
Blanford 2003; Mdellel & Ben Halima Kamel 2011).
Photoperiod (Dixon 1985; Robert 1988), relative
humidity (Missonier et al.1980), wind (Robert
1998) and rain (Jerraya 1997) were some of these
factors affecting P.persicae biology. Also, natural
enemies play a key role in managing the aphid
population characteristics (Northfield et al. 2010).
In Tunisia, different endemic natural enemies
have been reported to attack P.persicae, including
Coccinella algerica Kovar (Coleoptera: Coccinel-
lidae), Episyrphus balteatus De Geer, 1776 (Diptera:
Syrphidae) and Metasyrphus carollae (Diptera:
Syrphidae) and Chrysoperla carnea Stephens, 1836
(Neuroptera: Chrysopidae) (Mdellel & Ben
Halima Kamel 2015).Two entomopathogenic
fungi have been reported on P.persicae:Beauveria
bassiana (Ascomycota: Hypocreales: Cordycipita-
ceae) and Metacordyceps liangshanensis (Asco-
mycota: Hypocreales, Clavicipitaceae) (Mdellel
et al. 2015). Failures in effective control of the pest
*Author for correspondence. E-mail: rihemadouani@gmail.com
Received 23 October 2019. Accepted 22 September 2020
ISSN 1021-3589 [Print]; 2224-8854 [Online]
African Entomology
29(1): 59–68 (2021)
DOI: https://doi.org/10.4001/003.029.0059 ©Entomological Society of Southern Africa
aphid led to emphasis on classical biological
control agents using parasitoids. Therefore, a few
parasitoids are known to attack the brown peach
aphid such as Lysiphlebus fabarum (Marshall, 1896)
and Diaeretiella rapae (McIntosh 1855). Pauesia
antennata is commonly recorded as the most effi-
cient of them (Kairo & Poswal 1995). However, at
Sana’a in Yemen, the release programme was
achieved successfully as the parasitoid continued
to spread and establish (Cross & Poswal 1996; Kfir
et al. 2003). In Tunisia, P.antennata was introduced
in 2011 from Iran and five biological parameters
were studied in laboratory conditions (Mdellel
et al. 2015). Under field conditions, a preliminary
parasitoid establishment evaluation was done
on almond orchards (Adouani et al. 2017). Adult
development time, rate of mummification, rate of
emergenceandsex ratioofP.antennata weredeter-
mined for two generations. The presence of mum-
mies of P.persicae on almond trees proved the
host’s acceptance, and a dispersion of the parasit-
oid was accomplished. Efficiency of this parasitoid
can be affected by severe factors such as aphid
hosts, climatic conditions, genetic variation of
aphids and endosymbiont bacteria (Ortiz-Rivas
et al. 2009; Valenzuela et al. 2009). In Tunisia,
behaviour and relationship between aphid/
parasitoid sites and parasitoid efficiency were not
studied from 2011 (date of parasitoid introduc-
tion). The release of P.antennata against P.persicae
on peach orchards revealed two behavioural
responses: acceptance and rejection. In order to
shed light on this issue, the present study aimed
to clarify those responses by using a combined
approach that includes the study of partial sequen-
ces of the mitochondrial genes COI and cytb and a
fragment of the nuclear gene elongation factor-1
alpha (EF1α) as well as biological and morpho-
logical characters of the peach aphid samples
collected for acceptance and rejection sites.
MATERIAL AND METHODS
Aphid sampling and rearing
Live specimens of P.persicae were collected from
peach trees from Chott Mariam Sousse, Tunisia
(35°55”46.71”N 10°33”06.07”E) and were reared in
a greenhouse in the High Agronomic Institute of
Chott Mariem (ISA), Tunisia, under regulated
conditions at 21 ± 1 °C, 60 ± 10 % relative humid-
ity and a photoperiod 16L:8D on peach shoots in
Knop solution (Knop 1965; Mdellel et al. 2011).
Parasitoid sampling and rearing
Mummies of P.antennata were collected from
Taftan (Iran) in May 2015 (Taftan: 28°36’00”N
61°07’57”E) (altitude: 1498 m). Two-hundred and
fifty-five mummies were introduced into special
vials prior to emergence and were placed in the
entomology laboratory of the Higher Institute of
Agronomy, Chott Mariem (Tunisia) until total
emergence. Thirty-five emerged parasitoids were
released in Perspex cages (60 × 60 × 60 cm) con-
taining reared P.persicae on peach shoots. Three
droplets of honey were added in order to feed
adults, enhance fertility and extend parasitoid
longevity (Mondedji et al. 2002).
Methods of release
In June 2015, 12 pairs of parasitoids were col-
lected from the rearing colony and released on
two private farms of peach orchards (from locali-
ties, less than 110 km apart), preserved in organic
mode (Fig. 1). Ten trees at each site were selected
forreleasingsix pairs ofparasitoid P.antennata. The
two sites (Akouda-Sousse and Sfax) are located on
the Tunisian coast. The release of parasitoids was
made precisely between 10:00 and 12:00 when the
parasitic activity was high (Mdellel et al. 2015).
After release, mummies presence/absence were
recorded weekly until the end of August.
Collection of
P. persicae
for experiment
analyses
Live specimens of P.persicae were collected from
acceptance site (Site 1) and rejection site (Site 2).
Climatic and geographical information of the two
studies sites are given in Table 1.
60 African Entomology Vol. 29, No. 1, 2021
Fig. 1. Tunisian map representing zones of experiments.
Biological analyses
Comparative analysis of P.persicae behaviour
was carried out to evaluate plant resistance to
insects by antibiosis and antixenosis experiment
under laboratory conditions during January– Feb-
ruary 2016. No-choice tests to identify antibiosis,
which affects the biology and reproduction of the
insect (Dogimont et al. 2010), and choice tests to
establish antixenosis (or non-preference), in
which the plant is a poor host for the insect (van
Emden 2007). The objectives of this work were
to identify additional sources of resistance to
P.persicae on individuals collected from two zones
(acceptance and rejection of parasitoids).
Antibiosis. As a category of resistance to P.persicae
wasstudiedon peachbranches,shoots inKnopso-
lution (Knop 1965; Mdellel et al. 2011), in which
populations from parasitoid acceptance and rejec-
tion zones were reared. The selected branches
were infested by a female from the same mother
population. After 24 h, the apterous female and all
larvae except one were eliminated from the
branch. This larva was checked daily to measure
the larval longevity, the adult longevity and the
fecundity of P.persicae, continuously until the
death of the last aphid (Hill et al. 2004). In the
greenhouse, this experiment was repeated three
times.
Antixenosis. Three branches of peach, almond
and plum were reared together and arranged in a
single pot of Knop solution. Fifty adult aphids of
the same populations used in the antibiosis test,
were released in the centre of the pot, and 24 h
later the number of adults attracted to each branch
was counted and recorded (Laamari et al. 2008).
This experiment was also conducted three times.
Morphometric analyses
Thirty wingless viviparous adults of P.persicae
collected from each site, were swept with a brush
and stored in 70 % ethanol for morphological
examination. Using the techniques described by
Blackman & Eastop (1984), aphids were individu-
ally mounted on microscope slides and studied
under a Leica stereoscopic binocular microscope.
Sixteen continuous characters (body length, body
width, antennal total length, individual length of
antennal segments I, II, III, IV, V and VI, basal part
of antennal segment VI length, processus termi-
nalis length, siphunculus length, cauda length,
hind femora length, hind tibia length, and tarsus
length) were selected for morphometric study
(Agarwala et al. 2009). All morphological charac-
ters were measured in millimetres by microscopic
imaging software. Principal components analysis
(PCA) from MINITAB 14 was used for data
analysis.
Molecular analyses
DNA extraction and PCR amplification
All the samples were sampled in Tunisia. The
collected aphids, of the same two populations
used in the antibiosis and antixenosis test, were
stored in vials filled with 95 % ethanol for molecu-
lar studies and kept at –20 °C until DNA extraction.
We first examined the colonies under a binocular
microscope in order to select apterous adults.
Then, we used 20 individuals from each sampled
colony for DNA extraction and polymerase chain
reaction amplification (PCR). TotalDNA was sepa-
rately extracted from three individual adults from
each sample using the Hot SHOT (Hot Sodium
Hydroxide and Tris) method (Truett et al. 2000).
PCR amplification of the three gene fragments
analysed was carried out on 3 µl of the extracted
DNA. A 710 bp fragment of the 5’ region of the
mitochondrial cytochrome c oxidase subunit 1
(COI) was amplified using primers LCO1490 and
HCO2198, previously described by Folmer et al.
(1994). PCR conditions for COI amplification were
asfollows:94°C for1 min;35 cyclesof 94°C for30 s,
48°C for1 minand 68°C for1 min;a finalextension
step of 7 min at 68 °C was included after cycling.
Amplification of the elongation factor-1 alpha
(EF1α) gene fragment was performed using two
consecutive PCR reactions with primers Efs175
and Efr1 (5’GTGTGGCAATSCAANACNGG
Adouani
et al
.: Effect of brown peach aphid on
Pauesia antennata
(Hymenoptera) behaviour 61
Table 1.Geographic and climatic information about experiment sites (INM 2016).
Site Geographical coordinates Climate Annual average °C Annual average
temperature relative humidity %
Site 1: Sousse 35°5216N 10°3416E Semi-arid 25 ± 1 64 ± 10
Site 2: Sfax 34°4426N 10°4537E Arid 29 ± 1 57 ± 10
AGT3’) in the first reaction and then primers
Efs175 and Efr2 (5’TTGGAAATTTGACCNGG
GTGRTT3’) in the second hemi-nested reaction
(Moran et al. 1999). PCR conditions used in the first
reaction were: 94 °C for 1 min; 40 cycles of 94 °C for
30 sec, 50 °C for 1 min and 68 °C for 1.5 min; a final
extension step of 7 min at 68 °C was included after
cycling. The hemi-nested PCR was done similarly
but using 52 °C for the annealing step and using
1 µl of the first PCR product.
Sequencing and analysis of DNA sequences
PCR products were purified by ammonium
precipitation and reconstituted in 10 ml of LTE
buffer (10 mM Tris, 0.1 mM EDTA). Direct
sequencing of the amplified fragments was done
in both directions using PCR primers (Efr2 was
used as the reverse primer for sequencing the EF1
fragment). Sequencing was conducted using the
Big Dye Terminator version 3.1 Cycle Sequencing
Kit (Applied Biosystems) following manufac-
turer ’s instructions, and samples were loaded into
an ABI 3730XL automated sequencer. Chromato-
grams were revised and sequences correspond-
ing to each sample assembled using the Staden
package version 1.6.0 (Staden et al. 2000). Multi-
ple alignments and phylogenetic analysis of
sequences were done using MEGA6 (Tamura et al.
2011). It was done on a fragment of the mitochon-
drial DNA containing the 5’ region of the cyto-
chrome c oxidase 1 (COI), on a fragment of the
cytochrome gene b (cyt b) and on a fragment of the
nuclear gene coding for elongation factor-1 alpha
(EF1) of all samples.
PCRproducts werepurified using Montage PCR
Centrifugal Filter Devices (Millipore, Billerica,
MA, U.S.A.). Cycle sequencing reactions were
performed in both forward and reverse directions
using Big Dye Terminator version 3.1 Chemistry
(Applied Biosystems, Foster City, CA, U.S.A.), and
excess dye terminators were removed using
Performa DTR Gel Filtration Cartridges (Edge
Biosystems, Gaithersburg, MD, U.S.A.). Cycle
sequencing products were sequenced using an
ABI 3100 Genetic Analyser. Polymorphisms were
identified with Mutation Surveyor 2.51 software
(Soft Genetics, State College, PA, U.S.A.).
Statistical analyses
The larval and adult longevity and the fertility
data of antixenosis of the brown peach aphid were
compared using the analysis of variance (ANOVA)
test with MINITAB (version 14). Comparisons
among means were carried out by using the Tukey
test at α= 0.05. Principal components analysis
(PCA) was applied to determine the morphologi-
cal differences recorded for P.persicae from two
zones.
RESULTS
Biological results
The no-choice test showed significant difference
inlarvalongevity attwo sites(F= 5.44,d.f. = 5.114,
P< 0.001). Shortest larval longevity was 12.6 ±
2.08 days at Site 1 and the longest was 14.3 ± 1.52
days at Site 2. However, no significant difference
was found for the adult longevity of P.persicae
(Table 2). Pterochloroides persicae fecundity was
significantly different between two sites (F= 8.23,
d.f. = 5.114, P< 0.001). At Site 1, number of larvae/
female/day was 12.3 ± 11.06, therefore, at Site 2, it
was 20.2 ± 13.57.
Regarding the choice test, a significant differ-
ence was found in the preference of P.persicae after
24h(F= 10.14, d.f. = 4, P< 0.001). However, the
peaches at Site 1 attracted the highest number of
apterous aphids as opposed to the peaches at Site
2, which attracted the lowest number (Table 3).
However, the number of aphids on peach
branches was more than those on almond and
plum branches in both situations.
62 African Entomology Vol. 29, No. 1, 2021
Tab le 2. Larvae longevity, adult longevity and daily fecun-
dity of
Pterochloroides persicae
on peach of presence
(T1) and on peach of absence of parasitoid (T2).
T1 T2
Larvae longevity (days) 14.3 ± 1.52 a 12.6 ± 2.08 b
Adult longevity (days) 6.6 ± 1.15 a 6.4 ± 1.52 a
Daily fecundity (larvae/day) 20.2 ± 13.57 a 12.3 ± 11.06 b
Differences among two zones of peach were determined by Tukey
test. In columns, means followed by different letters are significantly
different (
P
< 0.05).
Tab le 3. The numbers of brown peach aphid attracted on
the peach of presence (T1) and on the peach of absence
(T2) of parasitoid after 24 h.
Peach Almond Plum
T1 18.6 ± 1.52 a 16.3 ± 1.52 b 5.6 ± 1.15 c
T2 13.6 ± 1.52 a 9 ± 1.15 b 4.6 ± 1.52 c
Differences among two zones of peach were determined by Tukey
test. In columns, means followed by different letters are significantly
different (
P
< 0.05).
Morphological results
A summary of the measurements, considering
16 morphological characters of the P.persicae
population after the exposure to the parasitoid is
given in Fig. 2. The results show a morphological
difference between zone of acceptance and zone
of rejection of parasitoid, it clearly separated the
population of P.persicae collected from Site 1 of
parasitoid’s acceptance from those collected from
Site 2 of parasitoid’s rejection. Indeed, there were
significant differences in four of the 16 characters.
Body length (F= 5.17, d.f. = 5, P= 0.0022), body
width (F= 9.78, d.f. = 5, P= 0.0021), antennal total
length (F= 21.02, d.f. = 5, P= 0.001) and hind
femora length (F= 11.48, d.f. = 5, P= 0.002)
appeared to be important predictors to separate
the two taxa (Fig. 3). However, no significant
differences were found in the rest of the measured
parameters: Antennal segment I length, antennal
segment II length, antennal segment III length,
antennal segment IV length, antennal segment V
length, antennal segment VI length, basal part of
antennal segment VI length, processus terminalis
length, siphunculus length, cauda length, hind
tibia length and tarsus length.
Molecular results
COI sequences analysis
A 710 bp DNA fragment partially containing the
mitochondrial COI coding sequence was ampli-
fied by PCR. Useful sequences obtained from each
sample consisted of 658 nucleotides. Two different
haplotypes were detected among P.persicae sam-
ples that differed in two nucleotides (positions 1
and 3 of the sequenced fragment). The polymor-
phism at position 1 is a silent T/A change affecting
a third codon position. The polymorphism at
position 3 is a replacement change involving a
second codon position. For the codon affected by
this polymorphism, haplotype I showed an ATT
(isoleucine) codon while haplotype II showed an
ACT (threonine) (Fig. 4). This molecular difference
was not correlated with host plant and geograph-
ical origin. However, it was clearly related to the
presence and absence of parasitoid (P< 0.01 after
a Fisher exact probability test). All samples collec-
ted in a zone of presence parasitoid were haplo-
type I which was identical to a P.persicae sequence
available in GenBank (accession number JN644
628). However, all samples collected in a zone of
absence parasitoid were haplotype II.
Cytb sequences analysis
The analysis of the cytb haplotypes, generated
by BLAST program, showed that our sequences
were 100 % identical to a P.persicae mitochondrial
cytb gene sequence available at GenBank (acces-
sion number KC110893). Therefore, no differences
were found in this mitochondrial gene and no
other analyses were done.
EF1
α
sequence analysis
The analysis of the EF1-alpha locus produced an
Adouani
et al
.: Effect of brown peach aphid on
Pauesia antennata
(Hymenoptera) behaviour 63
Fig. 2. Plot of principal components analysis (PCA) of the mean scores of morphometric parameters of
Pterochloroides persicae
for two peach zones after exposure to
Pauesia antennata
(Peach 1:site of acceptance and
Peach 2: site of rejection of parasitoid).
64 African Entomology Vol. 29, No. 1, 2021
Fig. 3. Plot of principal components analysis (PCA) of morphological characters contribute to the difference of
Pterochloroides persicae
between two zones of peach after the exposure to parasitoid.
Fig. 4. DNA sequences and translated protein sequences of 707 bp of the mitochondrial COI gene.This sequence is
for haplotype I (in peach of acceptance). The three nucleotides in positions 36, 37 and 38 due to polymorphism are
(AAC) for haplotype I and (TAT) for haplotype II.
alignment of 750 bp of which 635 bp were used
for the analyses after excluding primers and
bad quality bases from the end of sequences.
Our sequences were 100 % identical to sequence
available at database with accession number
FM174687.
DISCUSSION AND CONCLUSION
This study was done to find out if biological,
morphological and genetic variation of P.persicae
peach samples correlated with characteristics of
the exposure to the parasitoid P.antennata. Regard-
ing the biological aspect, the current study
revealed that there is a significant difference in the
brown peach aphid’s performance among expo-
sure to the parasitoid. Antibiosis experiment
showed that the longest longevity of P.persicae is
20.9 days on site of parasitoid’s acceptance and the
shortest was 19 days on site of parasitoid’s rejec-
tion. Nevertheless, Mdellel et al. (2015) and Khan
et al. (1998) reported it to be 22.11 days and 20.51
days, respectively, in controlled conditions. As for
daily fecundity, our results demonstrated that a
single female of P.persicae gave 20.2 larvae/day,
higher in zone of P.antennata presence. However,
Mdellel et al. (2015) showed that the daily fecun-
dity of P.persicae was 29.68 at 20 ± 1 °C. Karley et al.
(2002) proved that quality of host plants is an
important factor for the antibiosis resistance of
plants at the level of amino acids or nitrogen in the
phloem sap. In this regard, a significant difference
in the preference of the brown peach aphid was
found in the antixenosis experiment. Possibly due
to exposure to the parasitoid. The resistance factor
at Site 2 is more likely to be due to parasitoid
absence. Chemical traits like the toughness of the
epidermic tissues or trichomes on the surface of
the plant may indicate antixenotic traits against
aphids (Alvarez et al. 2007). However, it is not easy
to make a clear distinction between antibiosis and
antixenosis (Smith 2005). Many studies have
shown that plants have antibiosis towards phloem-
feeding insects, while having no antixenosis to
insects. Du et al. (2009) showed that the Bph14 gene
conferred the rice seedlings, Oryza sativa L., a resis-
tance to the brown plant hopper Nilaparvata lugens
Stål but had no influence on host acceptance of
this insect. Although the pea aphid Acyrthosiphon
pisum (Harris) displayed a similar host preference
between the resistant Medicago truncatula line A17
and line A20, it had significant differences in
phloem ingestion duration between these two
lines (Guo et al. 2012). According to morphological
traits, our work revealed the presence of differ-
ences between individuals of P.persicae collected
from two sites. These samples were divided into
two groups according to the presence and absence
of P.antennata by P.persicae. The two groups are
separated morphologically by four characters
such as body length. Measurements of all samples
are completely in accordance with Blackman &
Eastop’s (2000) reports. However, the aphid
morphology can be affected by host plant (Mdellel
et al. 2015), ecological zones and their physiologi-
cal condition (Margaritopoulus et al. 2007). Envi-
ronmental factors like geography (Madjdzabeh &
Mehrparvar 2009), temperature (Mdellel et al.
2012) and natural enemies may have important
effects for isometric and allometric growth in
aphids (Blackman & Spence 1994). The results of
mitochondrial COI analyses corresponded with
those of the morphological comparison, and
revealed two haplotypes: haplotype I (AAC)
and haplotype II (TAT). In agreement with the
report of Foottit et al. (2008), the level of intra-
specific variation described for the COI fragment
was average, this polymorphism was for three
nucleotides. It should be noted that partial COI
sequences correlated with presence and absence
of the parasitoid. All samples collected at Site 1
were haplotype I and all samples collected in zone
2 were of the new haplotype II (collected from
peach Site 2). COI gene is one the best DNA mark-
ers for higher taxonomic categories in most animal
phyla (Park et al. 2007). Our results suggest that
biological and morphological variation of our
samples are congruent with mitochondrial COI
and parasitoid information. The haplotype I was
the same as the one detected by Mdellel et al.
(2013), while the new haplotype II differed in a
single nucleotide. Both feeding site and seasonal
conditions seem to be key factors that have
contributed to the distribution of the maternal
lineages detected in P.persicae. In the same
context, Mdellel et al. (2011) suggested that the
presence of two different populations or maternal
lineages showing different dynamics along the
year. Individual analyses of Cytb were more con-
sistent with EF1αsequence analysis of each group
(Sites 1 and 2) of P.persicae than the mitochondrial
genes (von Dohlen et al. 2006). However, in insect
phylogeny, Cytb has rarely been used instead
of COI (Hebert et al. 2003). The homogeneity of
Adouani
et al
.: Effect of brown peach aphid on
Pauesia antennata
(Hymenoptera) behaviour 65
EF1αalong with mitochondrial DNA increases its
usefulness as a marker (Bull et al. 2003). However,
the first phylogenetic analysis using sequences of
the mitochondrial cytb gene identified a total of 25
haplotypes among which 21 were unique, differ-
ing only by point substitutions and are found
within the same group in the phylogenetic tree
(Kharrat et al. 2014).
In conclusion, morphological and genetic differ-
ences between P.persicae populations collected
from two zones could be related to physiological
variations, host plant nutrient composition,
endosymbionts and to unknown coexisting biotic
factors. At least two hypotheses may explain this
difference in parasitoid behaviour: may be genetic
variation in P.persicae or could be related to envi-
ronmental conditions like temperature, relative
humidity, wind, velocity, sunshine and rainfall.
Temperature could have much importance when
average in June to August fluctuated between
25 °C and 30 °C in Sousse and 27 °C and 34 °C
in Sfax. However, the results presented in this
work, obtained by COI sequences as well as with
morphological and biological characters can be
solid support to justify acceptance and rejection
of the parasitoid – a common conclusion needs
further investigation.
ACKNOWLEDGEMENTS
We are grateful to all members of the Genetics
Department of the Institute for Integrative Sys-
tems Biology especially N.S. Pérez, M. Barbera,
M. Collantes, University of Valencia, Spain, for
theirhelp withthe molecularaspects ofthe work.
§ORCID iDs
R.B. Adouani: orcid.org/0000-0002-5825-0323
L. Mdellel: orcid.org/0000-0002-6429-4015
M.B.H. Kamel: orcid.org/0000-0001-8309-0993
66 African Entomology Vol. 29, No. 1, 2021
REFERENCES
ADOUANI, R., MDELLEL, L., BEN HALIMA KAMEL,
M. & EHSAN, R. 2017. Preliminary observations on
introduction of Pauesia antennata Mukerji, 1950
(Hymenoptera, Braconidae) parasitoid of the brown
peach aphid Pterochloroides persicae Chlodkovsky,
1899 (Hemiptera, Aphididae) in Tunisia. Egyptian
Journal of Biological Pest Control 27(2): 227–230.
AGARWALA, B.K., DASAND, K. & RAYCHOUDHRY, P.
2009. Morphological, ecological and biological varia-
tions in the mustard aphid, Lipaphis pseudobrassicae
(Kaltenbach) (Hemiptera, Aphididae) from different
host plants. Journal of Asia-Pacific Entomology 12:
169–173.
ALVAREZ, A.E., TJALLINGII, W.F., VLEESHOUWERS,
V., DICKE, M. & VOSMAN, B. 2007. Location of
resistance factors in the leaves of potato and wild
tuber bearing Solanum species to the aphid Myzus
persicae.Entomologia Experimentalis et Applicata 121:
145–480.
ANSES. 2016. Fiche de Reconnaissance de Pterochloroides
persicae. Agence nationale de sécurité sanitaire de
l’alimentation, de l’environnement et du travail,
Montpellier, France.
ATEYYAT, M.A. & ABU-DARWISH, M.S. 2009. Insecti-
cidal activity of different extracts of Rhamnus disper-
mus (Rhamnaceae) against peach trunk aphid Ptero-
chloroides persicae (Homoptera: Lachnidae). Spanish
Journal of Agricultural Research 7(1): 160–164.
BEN HALIMA KAMEL, M. 2012. Aphid fauna
(Hemiptera, Aphididae) and their host association of
Chott Mariem, coastal area of Tunisia. Annals of Bio-
logical Research 3(1): 1–11.
BEN HALIMA KAMEL, M. & BEN HAMOUDA, M.H.
2004. Aphids of fruits trees in Tunisia. In: Simon, J.C.,
Dedryyer C.A., Rispe, C. & Hullé, M. (Eds) Aphids in a
New Millennium. Procceeding of the VIth Interna-
tional Symposium on Aphids. INRA Editions,
Versailles, France. 119–123.
BEN HALIMA KAMEL, M. & M.H. BEN HAMOUDA.
2005.A propos des arbres fruitiers de Tunisie. Notes
fauniques de Gembloux 58: 11–16.
BEN-ZE’EV, I.S., ZELIG, Y., BRITON, S. & KENNETH,
R.G. 1988. The Entomophthorales of Israel and their
arthropod hosts: Additions 1980–1988. Phytoparasitica
16: 247–257.
BERNAYS,E.A. &CHAPMAN, R.F. 1994.Host-Plant Selec-
tion by Phytophagous Insects. Chapman and Hall, Lon-
don, U.K.
BLACKMAN, R.L. & EASTOP, V.F. 2006. Aphids on the
World’s Herbaceous Plants and Shrubs. John Wiley &
Sons, Chichester, U.K. 1460 pp.
BLACKMAN, R.L. & EASTOP, V.F. 2000. Aphids on the
World’s Trees: an Identification and Information Guide.
CABI, Wallingford, U.K. 986 pp.
BLACKMAN, R.L. & EASTOP, V.F. 1984. Aphids on the
World’s Crops: an Identification Guide. John Wiley &
Sons, London, U.K. 476 pp.
BLACKMAN, R.L. & SPENCE, J.M. 1994. The effect of
temperature on aphid morphology, using a multi-
variate approach. European Journal of Entomology 91:
7–22.
BOLCHI SERINI, G. & CRAVEDI, P. 1985. Afidi delle
drupacee. Italia Agricola 122: 122–136.
BONFIELD, J.K., SMITH, K.F. & STADEN, R. 1995. A
new DNA sequence assembly program. Nucleic Acids
Research 23: 4992–4999.
BULL, N.J., SCHWARZ, M.P. & COOPER, S.J.B. 2003.
Phylogenetic divergence of the Australian allodapine
bees (Hymenoptera: Apidae). Molecular Phylogenetics
and Evolution 27: 212–222.
CHAU, A. & MACKAUER, M. 2001. Preference of the
aphid parasitoid Monoctonus paulensis (Hymenop-
Adouani
et al
.: Effect of brown peach aphid on
Pauesia antennata
(Hymenoptera) behaviour 67
tera: Braconidae, Aphidiinae) for different aphid
species: female choice and offspring survival. Biologi-
cal Control 20: 30–38.
CROSS, A.E. & POSWAL, M.A. 1996. Dossier on Pauesia
antennata Mukerji,Biological Control Agent for the
Brown Peach Aphid, Pterochloroides persicae in Yemen.
International Institute of Biological Control, Ascot,
U.K. 21 pp.
DIXON, A.F.G. 1985. Aphid Ecology. Chapman & Hall,
New York, U.S.A.
DOGIMONT, C., BENDAHMANE, A., CHOVELON, V.
& BOISSOT, N. 2010.Host plant resistance to aphids
in cultivated crops: genetic and molecular bases, and
interactions with aphid populations. Comptes Rendus
Biologies 333: 566–573.
DU, B., ZHANG, W., LIU, B., HU, J., WEI, Z., SHI, Z., HE,
R., ZHU, L., CHEN, R. & HAN, B. 2009. Identification
and characterization of Bph14, a gene conferring
resistance to brown plant hopper in rice. Proceedings
of the National Academy of Sciences of the United States of
America 106: 22163–22168.
EL TRIGUI, A., EL CHERIF, R. & AMMAR, E. 1989. Con-
tribution à l’étude du puceron brun Pterochlorus
persicae (Cholodk.). Nouveau ravageur des arbres
fruitiers à noyaux en Tunisie. Annales de l’INRAT
62(11): 40.
FOLMER, O., BLACK, M., HOEH, W., LUTZ, R. &
VRIJENHOEK, R. 1994. DNA primers for amplifica-
tion of mitochondrial cytochrome c oxidase subunit I
from diverse metazoan invertebrates. Molecular
Marine Biology and Biotechnology 3: 294–299.
FOOTTIT, R.G., MAW, H.E.L., VON DOHLEN, C.D. &
HEBERT, P.D. 2008. Species identification of aphids
(Insecta: Hemiptera: Aphididae) through DNA bar-
codes. Molecular Ecology Resources 8: 1189–1201.
GISH, M. & INBAR, M. 2006. Host location by apterous
aphids after escape dropping from the plant. Journal
of Insect Behavior 19: 143–153.
GUO, S-M., KAMPHUIS, L.G., GAO, L.L., KLINGLER,
J.P., LICHTENZVEIG, J., EDWARDS, O. & SINGH,
K.B. 2012. Identification of distinct quantitative trait
loci associated with defence against the closely
related aphids Acyrthosiphon pisum and A.kondoi in
Medicago truncatula.Journal of Experimental Botany 63:
3913–3922.
HARRY, M., ROBIN, S. & LACHAISE, D. 1998. L’utilisa-
tion de marqueurs génétiques polymorphes (RAPDs)
en entomologie evolutive et appliquee. Annales de la
Societe Entomologique Française 34 : 9–32.
HEBERT, P.D.N., RATNASINGHAM, S. & WAARD, J.R.
2003. Barcoding animal life: cytochrome c oxidase
subunit 1 divergences among closely related species.
Proceeding of the Royal Society B: Biological Sciences 270:
S96–S99.
HIDALGO, N.P., UMARAN, A. & ESPADALER, X. 2013.
El uso de la cibertaxonomía para seguir la expansión
de Pterochloroides persicae (Cholodkovsky, 1899) en la
Península Ibérica (Aphididae: Lachninae). Fotogragia
y Biodiversidad,BV News 2: 112–118.
HILL, C.B., LI, Y. & HARTMAN, G.L. 2004. Resistance to
the soybean aphid in soybean germplasm. Crop
Science 44: 1606–1608.
JERRAYA, A. 1997. Sur la dynamique des populations de
Hyalopterus pruni (Geoffroy) (Hom., Aphididae) dans
la région de Tunis. Journal of Applied Entomology 121:
373–382.
JERRAYA, A. 2003. Principaux Nuisibles des Plantes
Cultivées et des Denrées Stockées en Afrique du Nord; Leur
Biologie,Leurs Ennemis Naturels,Leurs Dégâts et Leurs
Contrôles. Maghreb Editions, Tunisia. 415 pp.
KAIRO, M.T.K. & POSWAL, M.A. 1995. The brown peach
aphid Pterochloroides persicae (Lachninae, Aphididae):
prospects for IPM with particular emphasis on classi-
cal biological control. Biocontrol News and Information
16: 41–47.
KARLEY, A.J., DOUGLAS, A.E. & PARKER, W.E. 2002.
Amino acid composition and nutritional quality of
potato leaf phloem sap for aphids. Journal of Experi-
mental Biology 205: 3009–3018.
KHAN, A.N., KHAN, I-A. & POSWAL, M.A. 1998. Evalu-
ation of different hosts and developmental biology
and reproductive potential of brown peach aphid,
Pterochloroides persicae (Cholodkovsky) (Lachninae)
underlaboratory conditions.Sarhad Journal of Agricul-
ture 14: 369–376.
KHARRAT, I., MEZGHANI-KHEMAKHEM, M.,
BOUKTILA, D., MAKNI, H. & MAKNI M. 2014.
Genetic variability of the giant black aphid, Ptero-
chloroides persicae (Hemiptera: Aphididae), based on
sequences of the mitochondrial cytochrome b gene.
Journal of the Entomological Research Society 16(2):
99–109.
KNOP, W. 1965. Quantitative Untersuchungen uber die
Ernahrungsprozesse der Pflanzen. Landwirtschaft-
lichen Versuchsstationen 7: 93–107.
LAAMARI, M., KHELFA,L. & COEUR D ’ACIER, A. 2008.
Resistance source to cowpea aphid (Aphis craccivora
Koch) in broad bean (Vicia faba L.) Algerian land-
race collection. African Journal of Biotechnology 7:
2486–2490.
LARKIN, M.A., BLACKSHIELDS, G., BROWN, N.P.,
CHENNA, R., McGETTIGAN, P.A. & McWILLIAM,
H. 2007. Clustal W and Clustal X version 2.0. Bioinfor-
matics 23: 2947–2948.
MADJDZADEH, S.M. & MEHRPARVAR, M. 2009. Mor-
phological discrimination of geographical popula-
tions of Macrosiphoniella sanborni (Gillette, 1908)
(Hem.: Aphididae) in Iran. North-Western Journal of
Zoology 5: 338–348.
MARGARITOPOULOS, J.T., TZORTZI, M., ZARPAS,
K.D., TSITSIPIS, J.A. & BLACKMAN, R.L. 2007.
Morphological discrimination of Aphis gossypii
(Hemiptera: Aphididae) populations feeding on
Compositae. Bulletin of Entomological Research 96:
153–165.
MARTINEZ-TORRES, D., MOYA, A., HEBERT, P.D.N. &
SIMON, J.C. 1997. Geographic distribution and sea-
sonal variation of mitochondrial DNA haplotypes in
the aphid Rhopalosiphum padi (Hemiptera: Aphidi-
dae). Bulletin of Entomological Research 87: 161–167.
MDELLEL L., BEN HALIMA KAMEL, M., TEIXEIRA,
D.A. & SILVA, J.A. 2011. Effect of host plant and tem-
perature on biology and population growth of
Pterochloroides persicae (Hemiptera, Lachninae). Pest
Technology 5(1): 74–78.
MDELLEL, L. & BEN HALIMA KAMEL, M. 2012.
68 African Entomology Vol. 29, No. 1, 2021
Aphids on almond and peach: preliminary results
about biology in different area of Tunisia. Redia XCV:
3–8.
MDELLEL, L. & BEN HALIMA KAMEL, M. 2012. Prey
consumptionefficiency andfecundityof theladybird
beetle, Coccinella algerica Kovàr (Coleoptera: Cocci-
nellidae) feeding on the giant brown bark aphid,
Pterochloroides persicae (Cholodkovsky) (Hemiptera:
Lachninae). African Entomology 20(2): 292–299.
MDELLEL, L., MARTINEZ-TORRES, D. & BEN
HALIMA KAMEL, M. 2013. Two mitochondrial
haplotypes in Pterochloroides persicae (Hemiptera:
Aphididae: Lachninae) associated with different
feeding sites. Insect Science 20: 637–642.
MDELLEL, L., BEN HALIMA KAMEL, M. &
RAKHSHANI, E. 2015. Laboratory evaluation of
Pauesia antennata (Hymenoptera: Braconidae), spe-
cific parasitoid of Pterochloroides persicae (Hemiptera:
Aphididae). Journal of Crop Protection 4(3): 385–393.
MISSONNIER, J., ROBERT, Y. & THOIZON, G. 1980.
Circonstances épidémiologiques semblant favoriser
le développement des mycoses à Entomophthorales
chez trois aphides, Aphis fabae Scop., Capitophorus
horni Börner et Myzus persicae (Sulz.). Entomophaga 15:
169–190.
MONDEDJI, D., AMEVOIN, K., NUTO, Y. & GLITHO,
I.A. 2002. Potentiel reproducteur de Dinarmus basalis
Rond. (Hymenoptera : Pteromalidae) en présence de
son hôte Callosobruchus maculatus F. (Coleoptera :
Bruchidae) en zone Guinéenne. Insect Science and its
Application 22(2): 113–121.
MORAN, N.A., RUSSELL, J.A., KOGA, R. & FUKATSU, T.
1999. Evolutionary relationships of three new species
of Enterobacteriaceae living as symbionts of aphids
and other insects. Applied and Environmental Microbi-
ology 71: 3302–3310.
MÜLLER, C.B., WILLIAMS, I.S. & HARDIE, J. 2001. The
role of nutrition, crowding and interspecific interac-
tions in the development of winged aphids. Ecological
Entomology 26: 330–340.
DOI: 10.1046/j.1365-2311.2001.00321
NORTHFIELD, T.D., SNYDER G.B., IVES, A.R. &
SNYDER, W.E. 2010. Niche saturation reveals re-
source partitioning among consumers. Ecology Letters
13: 338–348.
ORTIZ-RIVAS, B., MARTINEZ-TORRES, D. & PEREZ
HIDALGO, N. 2009. Molecular phylogeny of Iberian
Fordini (Aphididae: Eriosomatinae): implications for
the taxonomy of genera Forda and Paracletus.System-
atic Entomology 34: 293–306.
PAINTER, R.H. 1936. The food of insects and its relation
to resistance of plants to insect attack. American Natu-
ralist 70: 547–566.
PARK,M.H., SIM, C.J., BAEK, J. & MIN, G.S. 2007. Identi-
fication of genes suitable for DNA barcoding of
morphologicallyindistinguishable KoreanHalichon-
driidae sponges. Molecules and Cells 23: 220–227.
RAKHSHANI, E., TALEBI, A.A., STARY, P., MANZARI, S.
& REZWANI, A. 2005. Re-description and biocontrol
information of Pauesia antennata (Mukerji) (Hym.,
Brachonidae): parasitoid of Pterochloroides persicae
(Chol) (Hom., Aphidoidea, Lachnidae). Journal of the
Entomological Research Society 7: 59–69.
ROBERT, T. 1998. Responses of aphid parasitoids to
aphid sex pheromones: laboratory and field studies.
Ph.D. thesis, University of Nottingham, Nottingham,
U.K.
ROBERT, Y. 1988. Particularités éthologiques des
aphides: cycles, comportement de vol. In: Pensam,
A.N.P. (Ed.) Journées d’Information sur les Invertébrés
Vecteurs d’Agents Phytopathogènes. Hérault, Paris,
France. pp. 61–70.
SMITH, C.M. 2005. Plant Resistance to Arthropods – Molec-
ular and Conventional Approaches. Springer, Berlin,
Germany.
STOETZEL, M.B.S. & MILLER, G. 1998. Aphids
(Homoptera: Aphididae) colonizing peach in the
United States or with potential for introduction.
Florida Entomologist 81: 325–345.
TALHOUK, A.S. 1977. Contribution to the knowledge of
almond pests in east Mediterranean countries. VI.
The sap sucking pest. Zeitschrift für Angewandte
Entomologie 83: 248–257.
TAMURA, K., PETERSON, D., PETERSON, N.,
STECHER, G., NEI, M. & KUMAR, S. 2011. MEGA5:
molecular evolutionary genetics analysis using maxi-
mum likelihood, evolutionary distance, and maxi-
mum parsimony methods. Molecular Biology and
Evolution 28: 2731–2739.
THOMAS, M.B. & BLANFORD, S. 2003. Thermal biology
in insect–parasite interactions. Trends in Ecology and
Evolution 18: 344–350.
TRUETT, A.A., WALKER, J.A., WARMAN, M.L., TRUETT,
G.E., HEEGER, P. & MYNATT, R.L. 2000. Preparation
of PCR-quality mouse genomic DNA with hot sodium
hydroxide and Tris (HotSHOT). Bio Techniques 29:
52–53.
VALENZUELA, I., EASTOP, V.F., RIDLAND, P.M. &
WEEKS, A.R. 2009. Molecular and morphometric
data indicate a new species of the aphid genus
Rhopalosiphum (Hemiptera: Aphididae). Annals of the
Entomological Society of America 102: 914–924.
VAN EMDEN, H.F. & HARRINGTON, R. 2007. Aphids as
Crop Pests. CABI, Wallingford, U.K.
VON DOHLEN, C.D. & MORAN, N.A. 2006. Molecular
data support a rapid radiation of aphids in the Creta-
ceous and multiple origins of host alternation. Biolog-
ical Journal of the Linnean Society 71: 689–717.
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