The green lacewings (Neuroptera: Chrysopidae) are an important group of insect
predators (Dean and Satasook, 1983), that can be mass
reared in the laboratory and used against insect pests (Ashfaq
et al., 2002; Syed et al., 2008).
Their ability to adapt to a wide range of ecological factors (Ulhaq
et al., 2006) and tolerance to insecticides (Bigler,
1984; Nasreen et al., 2003) has made them
important in research and field application.
Predators play an important role in the complex ecosystem and the green lacewing
(Neuroptera: Chrysopidae) is one of these important predator (Zeleny,
1984), which is a powerful biological control agent against various homopterous,
lepidopterous and others soft bodied insect pests in field and green house (Duelli,
The host plant preferences and ovipositional preferences of the chrysopid predators
are factors which decide the effectiveness of the predators on the different
host plants (Ballal and Singh, 1999)
The species of the family Chrysopidae such as Chrysopa sp., Ankylopteryx
trimaculata Gerst., Ankylopteryx octopunctata F., Nothochrysa
evanescens, Mch. and Italochrysa ae-qualis Walk (Yunus
and Ho, 1980) and the recent recorded green lacewing Apertochrysa sp.
(Alasady et al., 2010) have been recorded from
Malaysian agro-ecosystem and Gleno-chrysa sp. has been reported from
Malaysian lowland tropical rain forest (Sajap et al.,
1997) and these natural enemies can play a very important role in agriculture
and forest ecosystem in Malaysia (Yunus and Ho, 1980;
Sajap et al., 1997; Alasady
et al., 2010).
The Apertochrysa sp., is one of the important species of Madagascan
Chrysopidae that is found wide spread African south of the Saharan and eastward
of African continent to the Pacific Region (Ohm and Holzel,
2002). It is also distributed and well known in India (Ramani
et al., 2002). However this genus is poorly known in South East Asia
and is newly record in Malaysia (NHM, 2008).
The hosts of Apertochrysa sp., include the mealy bug Maconellicoccus
hirsutus (Green) (Krishnamoorthy and Mani, 1989),
the spiralling whitefly, Aleurodicus disperses Russell (Ramani
et al., 2002) and the eggs of Helicoverpa armigera. This predator
can be reared successfully on eggs of Crocyra cephalonica in the laboratory
(Bakthavatsalam et al., 1994).
Such information about Chrysopidae just isnt available in Malaysia. Thus, the objectives of this study are to sample population of green lacewings from agro-ecosystem, to determine the important species of green lacewing, survey the occurrence of green lacewing on various plants in the field, study the occurrence of Apertochrysa sp. within the field and determine the percentage of parasitism of Telenomus sp. on eggs of Apertochrysa sp. in citrus and corn field.
MATERIALS AND METHODS
Study site: The study was carried out at University Putra Malaysia (UPM) fields, Serdang, Selan-gor, Malaysia (3°02 N, 101 42 E, 31 m elevation), during 2007-2008 in agro ecosystem area planted with diversity of plants, vegetables, grains, horticultures, various types of or-chards and herbs. The monthly rainfall average was (235±100.7) mm and daily mean temperature was 31°C±5.6.
Survey methods: Methods used to capture the adults and to sample the immature stages was as follows:
Handmade white plastic collision trap: Each trap (25 cm dia., 42 cm
ht.) was provided with cotton ball which had been infused with 25 mL of methyl
eugenol. The cotton balls were changed weekly. The traps were hung between trees
at different heights above ground. Same traps used by Sajap
et al. (1997) for capturing the Glenochrysa sp. at lowland
tropical rain forest.
Sticky traps: The trap consisting of square nylon screen measuring,
30x30 cm, smeared with trapping adhesive, a 5 mL glass vial containing eugenol
plugged with a cotton wick was placed on the screen. The traps were hung on
various heights above ground between the trees. The same sticky trap used by
Sajap et al. (1997) for capturing the Glenochrysa
sp. at lowland tropical rain forest.
Sweep net: Standard sweep net was used for capture the adults on herbs, vegetables, corn and or-chards.
Knockdown (Sondage sampling): Groundsheets were used around the cocoa
and citrus trees and then each tree was sprayed with cypermethrin at 2 ml L-1
to kill the insects. The ground sheets were left for 2 h before the insects
were collected. This to ensure that as many as possible insects knocked down
were collected (Southwood, 1978).
Shaking: A sheet of cloth (3x3 m) was laid out under the cocoa and citrus trees and then branches of the tree were shacked fast to bring down the immature stages of insects. They were collected and killed immediately using glass killing bottles.
Food attractant traps: White plastic collision traps, sticky plastic traps, delta traps were utilized with artificial diet (3 g sugar, 2.5 g yeast, 2.5 mL honey, 3 g powder milk) to attract the adults of green lacewings in citrus orchards field.
Air blower: Air blower was used to blow the immature stages from one side of tree and collect the insect using large plastic container (0.7x0.55 m) on the other side of tree. The collected insects were immediately killed using glass killing bottle.
Spray the adults food: Artificial diet was sprayed on the branches of citrus trees to encourage the adults of green lacewing to lay their eggs on citrus trees.
Color plastic card board traps: White, black, green, red, orange, brown, maroon and yellow plastic card boards (40x30 cm) smeared with trapping adhesive were hung on citrus orchards to attract the adults of green lacewings.
Eggs handmade collection: Direct eggs observation of green lacewing was conducted and then collected and counted by light microscope. The eggs were reared separately in plastic petri dishes on Corcyra cephalonica frozen eggs at 25±1°C, 55-85% RH and 12: 12D photoperiod conditions.
Survey the occurrence of Apertochrysa sp. on various plants: Forty three plants were surveyed by direct egg observation of green lacewing on leafs, trunks and fruits. The plants as listed in Table 1.
The parasitism of Telenomus sp. on the eggs of Apertochrysa sp. collected from citrus trees and corn plants: The eggs of green lacewing on leaves of citrus trees and corn plants were collected, counted, recorded and kept in the laboratory. The eggs were isolated based on the color, white, green, brown and black eggs and then placed in plastic cylindrical containers (12x17.5 cm). The eggs were monitored daily until hatching while un-hatch eggs especially the brown and black eggs were monitored until the parasitoids emerged. The numbers of parasitoids were recorded.
The eggs were collected at 6:45 am to 7:45 am to avoid other predators on eggs of green lacewing especially ants.
The percentage of parasitism of Telenomus sp. on the eggs of green lacewing on corn plants and citrus trees was calculated using the following equation:
The eggs of green lacewing from citrus trees were collected between 31-7-2007 to 19-7-2008, while the eggs from corn plants were collected in January, February, March and April of 2008.
||List of selected plants surveyed for green lacewings during
The occurrence of Apertochrysa sp. within the field: The area of the corn field was 17x28 m. Randomized Complete Block Design (RCBD) with 3 replicates were used in the experiment. The distribution of eggs of green lacewing in the corn field was observed by collecting the eggs from the plants at intervals of 2 m from the east to west of the field. The eggs were collected from 10 randomly selected plants. The eggs were also collected from the corn plants at all four borders of the field.
Identification of collected specimens: The eggs of green lacewing collected from citrus orchards were reared separately until emergence of the adults. Eggs cluster collected from the same leaf was considered belonging to the same species. Some of the adults obtained from rearing culture were killed and kept in specimen vials containing 70% alcohol. The vials were labeled accordingly (Date of collection, locality, common and technical name).
The eggs of green lacewing that were primarily infected by parasitoid (black eggs) were collected, reared in laboratory until the adults of parasitoids emerged. These parasitoids were collected, killed and kept in vials containing 70% alcohol. These specimens were sent to Natural History Museum (NHM) in Britain for identification.
Statistical analysis: The mean of eggs per plant of Apertochrysa sp. and the percentage of eggs occurred were used to determine the occurrence of Apertochrysa sp. on various plant species.
The data collected on distributions of eggs of green lacewing Apertochrysa sp. within the field of corn plant were analyzed by using analysis of variance (ANOVA) followed by LSD test.
The percentages of parasitism of Telenomus sp. on the eggs of Apertochrysa
sp. found on citrus trees and corn plants were assessed with chi-square
test, depend on the deviations from a 4% parasitism level obtained by Ruberson
et al. (1995) (df = 2, χ2calc.= 31.66, p<0.05).
RESULTS AND DISCUSSION
Survey methods: All methods used to survey the green lacewing failed
to capture the adults. This was attributed to three reasons; firstly the low
percentage of green lacewing in the survey area, secondly no much information
on the green lacewing behaviors in the field and thirdly most of these methods
needed more optimizations. These results were confirmed by many previous studies
for instance using water traps baited with fruits in Gombak Forest Reserve did
not catch any green lacewings (McLure, 1980) and using
the sweep net by Wong (1984) also failed in Pasoh Forest
Reserve. Similar results were obtained by Stork (1987)
and Sajap and Kotulai (1992) when using the pyrethrum
knockdown in lowland tropical rain forest of Bukit Sulang. Nevertheless the
sticky traps and white plastic collision traps baited with eugenol succeeded
to attract the adults of Glenochrysa sp. in Malaysian low-land tropical
forest (Sajap et al., 1997). It is extremely
difficult to observe the adults of green lacewings in the field because of unknown
flight behaviors, small body size and nocturnal flight activity (Chapman
et al., 2003).
The specimens identification: All green lacewing specimens send
to the Natural History Museum in Briton were identified as follow:
While the parasite specimens on the eggs of green lacewing were identified
|| Suvae Johnson and Bin (NHM, 2008).
The occurrence of green lacewings on various plants: Table
2 shows that the citrus orchards contained the highest number of eggs of
Apertochrysa sp. (3.98 eggs/plant) followed by chili pepper (0.54 eggs/plant),
water melon (0.33 eggs/plant) and cucumber (0.25 eggs/plant). The rest of the
plants recorded 0.13 or less eggs/plant.
No eggs were found on Durian, Jakfruit (Nangka), Pulasan, Rambutan, Mangosteen, Ciku (Sapodilla), Cocoa, Palm oil, Coconut, Papaya, Star fruit, Cempedak, Guava, Jatro-pha, Strawberry, Pineapple, Cauliflower, Tea shrub, Dragon fruit, Tobacco, Bamboo, Car-nation, Bougainvilla, Kenaf and Pieria plant.
|| The occurrence of green lacewing Apertochrysa sp.
eggs on various plant species (eggs Plant-1)
The results also showed that all green lacewing specimens collected belong to single species which is Apertochrysa sp.
The variation in percentages of occurrence of eggs of green lacewing on various
plants may be attribute to influence of females attraction to lay their eggs
on the plant because of the odor of plant and prey (Zhu
et al., 2005; Hagen et al., 1976)
or may be because of plant architecture (Clark and Messina,
1998; Ahmad and Ali, 1989). The current results
confirmed the results obtained by Ballal and Singh (1999)
when they reported the variations of ovipositional preferences and occurrences
of Ch. carnea (Stephens), Mallada boninensis (Okamoto) and M.
astur (Banks) on three plants; cotton, sunflower and pigeon pea.
However many biotic factors and environment factors working together to obligate the females of green lacewing to lay their eggs on specific plant, for instance in our field, it is been noticed that numbers of preys like mealy bugs and citrus black flies Alerocanthus woglumi may increase the preference of females of green lacewing to lay their eggs on citrus orchards, at the same time, it is been noticed huge number of white flies Aleurodicus disperses Russell on guava trees but no eggs of green lacewing were noticed.
Table 3 shows that 65.84% of eggs collected were on citrus trees while 26.48% of eggs were on vegetables plants. Although high number of eggs were collected from corn plants (sweet and cereal), the percentage of eggs Apertochrysa sp. were very low (2.33%) comparing with eggs collected from citrus trees. The lowest percentage was recorded on herbs plants (1.59%). These results show clearly that the females of Apertochrysa sp. preferred to lay their eggs on citrus trees and the vegetables plants more than other plants. It seems the odor of citrus trees has special effect.
However the percentage of eggs of green lacewing per plant was very low, because
of two main raisons; 1- the predation on eggs of Apertochrysa sp. especially
by the ants and dragon fly, as was documented by Silva et
al. (2007) and 2- the parasitism by Telenomus sp. (Hymenoptera:
Scelinoidae) on the eggs of Apertochrysa sp. as confirmed by Krishnamoorthy
and Mani (1989) and Ruberson et al. (1995).
|| Percentage of occurrence of Apertochrysa sp. on various
types of plants
|| The percentage of parasitism of Telenomus sp. on
eggs of Apertochrysa sp. found on citrus orchards and corn plants
|Within the same columns, means followed by the different letters
are significantly different from each other at p<0.05 (df = 2, χ2calc.
The parasitism of Telenomus sp. on the eggs of Apertochrysa sp.
in citrus trees and corn plants fields: Table 4 shows
that there is high percentage of parasitism of Telenomus sp. parasitoid
on the eggs of green lacewing Apertochrysa sp. and shows the significant
differences be-tween the percentage of parasitism on the eggs of green lacewing
found on citrus trees and corn plants. The highest percentage of parasitism
was recorded on the eggs of Apertochrysa sp. on corn plants. This study
showed higher level of percentage parasitism than the results of previous research
by Ruberson et al. (1995).
These results also confirmed the previous results by Alrouechdi
et al. (1984) and Krishnamoorthy and Mani (1989)
that the Telenomus sp. is an important parasitoid that can reduce the
effectiveness of biological control. However the effect of Telenomus
sp. on chrysopids populations still unclear in the field (Ruberson
et al., 1995).
The occurrence of Apertochrysa sp. eggs within the field: Table 5 shows the occurrence of eggs of Apertochrysa sp. was different from site to site within the field.
Observations showed the females of Apertochrysa sp. prefer to lay their eggs on the corn plants planted in the east sites of the field, especially the first 10th m after east border recorded 57.13% off eggs collected, followed by west sites (from 20 m after east border to west border) 21.73%, while lowest percentage were noticed in central sites (10 to 20 m after east border) 19.86%. Within the field, the east border (12.42%), 2nd m (19.25%), 8th m (21.74%) and 28th m (11.80%) after east border recorded the highest percentage of eggs of Apertochrysa sp. with no significant differences between them. While significantly differences were recorded between east border, 2nd m, 8th m and 28th m compared with other sites. The highest occurrence of Apertochrysa sp. was found in east border recorded significant differences compared with west, north and south border.
These variations of occurrence in field attribute to two main reasons, the
sun light and availability of food. These findings agree with the results obtained
by Klein et al. (2002) when they found the positively
effect of light intensity on the cacao arthropod community in cacao agro forestry
|| The Mean±SD and the percentage of eggs occurrence
of Apertochrysa sp. on different locations within the corn field.
|Within the same column, means followed by the different letters
are significantly different from each other at p = 0.05 (LSD = 6.637, F
= 2.457, d.f = 18, 36)
While the effect of food availability were noticed by Zheng
et al. (1993).
All captured specimens belong to a single species in this research area during the survey period that is the Apertochrysa sp.
The Apertochrysa sp. is newly recorded in Malaysian agro ecosystem can be found on different type of plants, orchards, vegetables, grains, horticulture and herbs with different percentages occurrence and the highest eggs density of Apertochrysa sp. was recorded on citrus orchards.
The Telenomus sp. is also newly recorded as a very important parasitoid on the eggs of green lacewing Apertochrysa sp. and with other predator especially the ant and dragon fly can made the occurrence of it very low in the field of citrus and corn.
The sun light and availability of food are the main important factors that can affect the distribution Apertochrysa sp. within the field.
All methods used to capture the adults and to sample the immature stages failed except the direct observation of eggs mainly because the low percentage of green lacewings in the field.