Influence of Varying Temperature on the Development and Fertility
of Plutella xylostella (L.) (Lepidoptera: Yponomeutidae) on Cabbage
Syed Kamran Ahmad,
Parvez Qamar Rizvi
A laboratory study was conducted to find out the development and fertility
of Plutella xylostella at varying temperatures (20±1, 25±1
and 20/25±1°C, coupled with 70±5% RH and 12 h L: 12
h D). The observations of two successive generations revealed that P.
xylostella registered maximum life span of 33.13±1.494 days
at 20±1°C, followed by 30.75±1.513 days at 20/25°C
and 28.84±1.847 days at 25±1°C. When, a comparison was
made between the developmental stages of P. xylostella at different
temperature, it ranged from 3.0-4.0, 8.0-13.0, 1.0-1.5, 4.0-6.0 and 5.0-15.0
days at egg, larval, prepupal, pupal and adult stage, respectively. Although,
the minimum temperature (20±1°C) influenced the highest natality
(11 days) of the female, it also persuades highest fecundity of 104.42
eggs/female against the lowest of 78.26 eggs/female at 25±1°C.
Similarly, mean length of generation of P. xylostella also attained
high value of 27.92 days at 20±1°C and the low of 24.70 days
at 25±1°C. However, P. xylostella exhibited a markable
variation in different rates of increase (intrinsic, finite and annual)
at different temperatures; it scheduled high value at fluctuating temperature
(20/25±1°C) in comparison to constant temperature (20±1
and 25±1°C). Likewise, a high carrying capacity (26.57 female/female/day)
was also observed at fluctuating temperature (20/25±1°C), against
the low (18.52 female/female/day) at 25±1°C. Therefore, the
temperature is a crucial abiotic factor, governs the certain biological
attributes of various insects. Both minimum and fluctuating temperatures
favor the development and survival of Plutella xylostella on cabbage
under controlled condition.
Cabbage, Brassica oleracea var. capitata is one of the
important cruciferous vegetable crops in the world. The most important
factor limiting cabbage production is the presence of pests especially
insects that cause regular quantitative as well as qualitative losses
in diverse ecological conditions. This crop attacked by number of insect-pests
at different developing stages. Among them diamond back moth, Plutella
xylostella (L.) is the most destructive one (Mahla et al.,
2005; Kumar et al., 2007). In India this pest has national importance
on cabbage, causing 50-80% annual loss in marketable yield (Devjani and
Singh, 1999; Ayalew, 2006).
Although, this insect is believed to have originated in the Mediterranean
area and now it is the most universally distributed pest of all lepidopterans
(Hemchandra and Singh, 2005). The purpose of present investigation is
to provide detailed information of life table of Plutella xylostella
and generates simple but more informative statistics that giving the comprehensive
description of the survivorship, development and reproduction of this
insect. Therefore the study was aimed to find out development and female
fertility of diamondback moth, Plutella xylostella at varying temperatures.
MATERIALS AND METHODS
To maintain the culture of P. xylostella, larvae were collected
from cabbage plants grown in experimental fields of the Department of
Plant Protection, Aligarh Muslim University, Aligarh, during late January
and early February, 2007. They were released in batches of 50 in broad
mouthed plastic jars (diameter 15 cm and height 25 cm) for obtaining pupae
at different temperatures (20±1, 25±1 and 20/25±1°C,
coupled with 70±5% RH and 12 h L: 12 h D) in BOD incubator. The
bottom of each plastic jar was lined with sphere of blotting paper. The
mouths of the jars were covered with muslin cloth. Fresh leaves of cabbage
were provided as food to the larvae, daily. The lower end of the cabbage
leaf was wrapped with cotton swab to maintain the turgidity. The pupae
collected from each of jars from respective temperatures were kept again
in separate plastic jars of the same size as above for emergence of adults.
After emergence of adults, they were sexed and paired (20 pairs) in each
of egg laying jars. There were four replications of each egg laying jars
were kept at different temperatures. After adult emergence, the egg laying
jars were provided with cabbage leaves to obtain eggs. The leaves were
removed daily and examined, using hand lens for finding out the eggs.
The eggs were removed with the help of soft wet camel hair brush. Counted
number of same age old eggs obtained from the adults of P. xylostella
were placed over the wet blotting paper in petridishes and allowed to
hatch at different temperatures. Egg hatch percentage was recorded from
each aliquot and subsequently adjusted, so that life table commenced with
Fluctuating temperature (20/25±1°C) was maintained by transferring
the rearing jars from one constant temperature (20±1°C) to
another (25±1°C) at an interval of 12 h and L:D of 12:12 h.
From hatched eggs, one hundred 0-10 h old larvae were collected with the
help of soft wet camel hair brush. Larvae were individually reared in
plastic vials (5x10 cm) on fresh cabbage leaves. Initially, fresh leaves
provided as food, were changed after three days of larval feeding. Thereafter,
the food was changed daily. The longevity and mortality of each larval
instars, prepupal, pupal and adult stage was recorded daily at respective
To record fecundity, ten pairs of adult moths of different age group
were released individually in plastic jars (15x25 cm) along with leaves
and 10% sugar solution, soaked in cotton swab, as food for adults. The
sugar soaked cotton swab was hanged with a thread 15 cm below from the
mouth of the jar. The egg laying jars along with individually paired moths
of different age group were kept at different temperatures (20±1,
25±1 and 20/25±1°C) for obtaining eggs. Black paper
sheet was lined along the inner surface of each of the jars. Since, moths
not only laid the eggs on leaves but also on the surface of the paper,
therefore, black paper sheet as well as leaves were examined daily, using
hand lens to count the number of the eggs laid by a single female of different
age group. Fresh leaves and black paper sheet were used daily until the
egg laying of each of the females was completed at different temperatures.
Longevity of female was also recorded in each of replications. This way
the observations for the survival and fertility of female were recorded
and the table was constructed with the following assumptions:
The table was constructed on the suggestions made by Birch (1948) and
Southwood (1978). It consisted of following columns:
||The survivorship rates were assumed to be the same for
both the sexes, as it was not possible to identify the sexes prior
to the adult stage.
||The sex could not be identified at the egg stage. Therefore a sex
ratio of 1: 1 was considered in each batch of eggs (Birch, 1948; Southwood,
||Pivotal age of the class in days.
||Number of females alive at the beginning of the age interval x (as
fraction of initial population of one).
||Average number of eggs laid per female in each age interval assuming
50:50 sex ratio and computed as:
|Where, Nx =Total natality per female off springs in each
Following parameters were also calculated for survivorship and fertility
||Net Reproductive or Replacement Rate (Ro):
This is also referred to as the carrying capacity of insect. The information
on the multiplication rate of a population in one generation is obtained
from it. It is denoted as,
||Mean length of Generation (T): It is defined
as the mean period between the birth of the parent and the birth of
their off springs. This period is a weighed approximate value since
the progeny is produced over a period of time and not at a definite
time. Calculation followed the method suggested by Dubin and Lotka
||Intrinsic Rate of Increase (r): It is also denoted
by r or rm or rmax and called as biotic potential.
It is defined as the instantaneous rate of increase of a population
in a unit time under a set of ecological conditions (Birch, 1948).
An estimate of the intrinsic rate of increase (r) can be calculated
by using the following equation:
r = [Loge Ro]
/ T (for rough estimation)
= 1 (for accurate estimation of r)
||Net reproductive rate
|| Mean length of the generation
||Finite Rate of Increase (λ): It provides the information
about the frequency of the population multiplication in a unit of
time (Birch, 1948). It is denoted as
λ = er. Taking log on both sides
we get loge λ = loge er
Where, λ = Antilog er
||Potential Fecundity (Pf): It expresses
the total number of eggs laid by an average female in her life span.
It is obtained or calculated by adding up the age specific fecundity
||Doubling Time (DT): It is defined as the time required for
the population to double and is calculated as follows:
||Annual Rate of Increase (ARI): This can be calculated
from the intrinsic rate of increase (r) or finite rate of increase
(λ) or doubling time (DT) or the net reproductive rate (Ro)
assuming that the rate of increase was constant throughout the year.
ARI = 365 = e365r = 2365/DT
It was inferred from the Table 1 that the P. xylostella exhibited
longest incubation period at 20±1°C (3.89±0.046 days)
and shortest at 25±1°C (3.27±0.121 days). Similarly,
all the larval instars (1st to 4th) also registered their maximum span
(3.98±0.017, 2.79±0.104, 2.76±0.102 and 2.96±0.023
days, respectively) at 20±1°C and the minimum (3.64±0.170,
2.59±0.140, 2.57±0.120 and 2.49±0.142, respectively)
at 25±1°C. Likewise, prepupal and pupal stages also tuned their
highest developmental period (1.35±0.124 and 5.13±0.219
days, respectively) at 20±1°C in contrast to lowest (1.00±0.033
and 4.82±0.243 days, respectively) at 25±1°C. Nevertheless,
adult stage exhibited a considerable variation in longevity of P. xylostella
at all the temperatures. The maximum adult longevity (10.27±0.859
days) was recorded at 20±1°C followed by 20/25±1°C
(9.21±0.878 days) and 25±1°C (9.21±0.696 days).
However, the overall developmental period of P. xylostella was
recorded highest (33.13±0.859 days) at 20±1°C against
the lowest (28.84±1.847 days) at 25±1°C.
Female Survival and Fertility
It is evident from data that females P. xylostella commenced egg
laying during definite period of pivotal age. The longest duration of
natality of 11 days was recorded at 20±1°C. However, a marked
variation in egg laying capacity of female was documented at different
temperatures. It was observed that the peak egg laying (18.01 eggs day-1),
was recorded at 20±1°C on 28th day, whereas, dip (1.95 eggs
day-1) at 20/25±1°C, on 23rd day (Table 2).
When a comparison was made in various life parameters at different temperatures,
it was discerned that superior potential fecundity (104.42 eggs/female),
was recorded at 20±1°C, as compared to inferior (78.26 eggs/female),
at 25±1°C (Table 3). A high carrying capacity (26.57 female/female/day)
was observed at a fluctuating temperature of 20/25±1°C, against
the low (18.52 female/female/day) at 25±1°C. Whereas, the maximum
mean length of generation of Plutella xylostella was recorded at
20±1°C (27.92 days) and the minimum at 25±1°C (24.70
days). However, the intrinsic rate of increase was of higher order (0.1228
female/female/day) at 20/25±1°C, against the low (0.1165 female/female/day)
at 20±1°C. Though, the finite rate of increase did show a considerable
variation, it was higher at 20/25±1°C (1.1307), followed by
20±1°C (0.1165) and 25±1°C (0.1189 females/female/day)
(Table 3). When Diamond Back Moth reared at 20±1°C took longest
period of 5.95 days for the population to double as compared to shortest
of 5.64 days at fluctuating temperature, 20/25±1°C. There was
a considerable effect of varying temperature on Annual Rate of Increase
(ARI) of P. xylostella. The maximum annual rate of increase (2.97E+19)
was computed at 20/25±1°C followed by 25±1°C (7.05E+18)
and 20±1°C (3.03E+18) (Table 3).
||Development of diamond back moth, Plutella xylostella
at varying temperatures on cabbage
|The values in the parenthesis showing the range of development
in days at respective stage
||Life and fertility table of P. xylostella on cabbage
at varying temperatures
||Summary of life parameters of P. xylostella
at varying temperatures
A comparative study of P. xylostella on different developmental
stages revealed that the value of its development ranged 3-4, 8-13, 1.0-1.5,
4-6 and 5-15 days at egg, larval, prepupal, pupal and adult stage, respectively
at different temperatures. Similar judgment also made by Hemchandra and
Singh (2003). They reported the incubation, larval, pre pupal, pupal and
adult period of P. xylostella ranged 3-4, 5-11, 1-2, 4-5 and 8-10
days, respectively at various temperatures. However, Devjani and Singh
(1999) was recorded the incubation, larval, prepupal, pupal and adult
duration of diamondback moth as 2.10, 10.5, 1.6, 6.06 and 16.7 days, respectively
at 23±1°C and 45±2% relative humidity.
It was also evident from the present findings that Plutella xylostella
registered maximum range of its life span of 23-40 days at 20±1°C,
followed by 23-38 days at 20/25±1°C and 19-37 days at 25±1°C.
Similar study also made by Hemchandra and Singh (2003), who reported that
the total life span of Plutella xylostella ranged from 28-34 days
Female Survival and Fertility
It was inferred from the result that the longest duration of natality
was recorded at 20±1°C against the shortest at 25±1°C
and the peak egg laying was also recorded highest at 20±1°C,
whereas, the minimum at 25±1°C. These findings are the corroborative
study of Shirai (2000) and Liu et al. (2002), who concluded that
the female did not exhibited good tolerance with high-temperature as compare
to low and the fecundity also decreased with increase in temperature.
In the present findings the maximum mean length of generation was recorded
at 20±1°C against the minimum at 25±1°C. Similar
observations also made by Liu et al. (1985), who reported maximum
generation length of 22.69 days at 20±1°C. However, the judgment
of Hemchandra and Singh (2005) also complete agreement of present findings,
who reported longest mean length of generation of 29.48 days at 22.2±1°C.
The highest carrying capacity was observed at fluctuating temperature
(20/25°C) as compare to lowest at constant temperatures (20±1
and 25±1°C). The results obtained by Shirai (2000) and Chen
and Liu (2004) also support these findings.
In present experiment, different rates of increase viz., intrinsic, finite
and annual rate of increase were maximum at 20/25±1°C in contrast
to minimum at 20±1°C. These findings has been well supported
by the findings of Liu et al. (1985), Reddy and Singh (1998),
Hemchandra and Singh (2003, 2005) and Navatha and Murthy (2006). The population
of P. xylostella required maximum time to become double at 20±1°C
and minimum at fluctuating temperature of 20/25±1°C. The corroborative
study also made by Devjani and Singh (1999), Shirai (2000), Liu et
al. (2002), Chen and Liu (2004), Hemchandra and Singh (2003, 2005)
and Kumar et al. (2007).
It is accomplished from present findings that the development of the
subsequent stages of P. xylostella and the fecundity of female
decreased with increase in temperature, whereas, population took the shorter
period to become double at fluctuating temperature (20/25±1°C).
Therefore, both minimum and fluctuating temperatures favor the development
and survival of Plutella xylostella on cabbage under controlled
condition. This study also gave the detail information of survival and
fecundity of P. xylostella at different temperatures that is necessary
for management of this pest in cabbage ecosystem.
Authors are grateful to the authority of the Department of Plant Protection,
Faculty of Agricultural Sciences for providing necessary facilities during
the experimental work.
1: Ayalew, G., 2006. Comparison of yield loss on cabbage from diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) using two insecticides. Crop Prot., 25: 915-919.
2: Birch, L.C., 1948. The intrinsic rate of natural increase of an insect population. J. Anim. Ecol., 17: 15-26.
CrossRef | Direct Link |
3: Chen, F. and S. Liu, 2004. Effects of low and subzero temperature on a Plutella xylostella laboratory population. Ying Yong Sheng Tai Xue Bao, 15: 99-102.
Direct Link |
4: Devjani, P. and T.K. Singh, 1999. Field density and biology of diamond back moth P. xylostella L. (Lepidoptera: Yponomeutidae) on cauliflower in manipur. J. Adv. Zool., 20: 53-55.
Direct Link |
5: Dubin, L.I. and A.J. Lotka, 1925. On the true rate of natural increase: As exemplified by the population of the United States, 1920. J. Am. Statist. Assos., 20: 305-339.
CrossRef | Direct Link |
6: Hemchandra, O. and T.K. Singh, 2003. Life table, rate of increase and stable age distribution of P. xylostella (L.) on couliflower. Ann. Plant Prot. Sci., 11: 269-273.
Direct Link |
7: Hemchandra, O. and T.K. Singh, 2005. Life table, age-distribution and life expectancy of Plutella xylostella (Linnaeus) on Brassica juncea var. rugosa. Ann. Plant Prot. Sci., 13: 302-306.
Direct Link |
8: Kumar, P., C.S. Prasad and G.N. Tiwari, 2007. Population intensity of insect pests of cabbage in relation to weather parameters. Ann. Plant Prot. Sci., 15: 245-246.
9: Liu, H., H. Chi, C.N. Chen and K.S. Kung, 1985. The population parameters of the DBM, P. xylostella (L.) on common Kale. Plant Protec. Bull. Taiwan, 27: 145-153.
Direct Link |
10: Liu, S.S., F.Z. Chen and M.P. Zalucki, 2002. Development and survival of the diamondback moth, Plutella xylostella, at constant and alternating temperatures. Environ. Entomol., 31: 221-231.
Direct Link |
11: Mahla, R.S., S. Singh and P. Chaudhary, 2005. Management of diamondback moth, Plutella xylostella (L.) Larvae by entomopathogenic fungus Metarhizium anisopliae. Indian J. Entomol., 67: 342-344.
Direct Link |
12: Navatha, S. and K.S. Murthy, 2006. Host preference for oviposition and feeding by diamond back moth, Plutella xylostella Linn. Ann. Plant Prot. Sci., 14: 283-286.
Direct Link |
13: Reddy, C.N. and T.V.K. Singh, 1998. Rate of increase and stable-age distribution of Pluetlla xylostella on cabbage at Hyderabad. Indian J. Entomol., 60: 329-333.
14: Shirai, Y., 2000. Temperature tolerance of the diamondback moth, Plutella xylostella (Lepidoptera: Yponomeutidae) in tropical and temperate regions of Asia. Bull. Entomol. Res., 90: 357-364.
Direct Link |
15: Southwood, T.R.E., 1978. Ecological Method with Particular Reference to the Study of Insect Population. The English language Book Society and Chapman and Hall, London, pp: 524.