ABSTRACT The life history and predation rate of Lemnia biplagiata ( Swartz ) fed on Aphis gossypii Glover was studied at 25 # C in the research lab. The natural informations were analyzed based on the age-stage,
two-sex life tabular array to take the variable developmental rate among persons and both sexes into
consideration. The intrinsic rate of addition ( R ) is 0.1570 vitamin D # 1, the Tnite rate of addition ( # ) is 1.170
d # 1, the net reproduction rate ( R0 ) is 291.1 offspring per person, the average coevals clip ( T )
is 36.2 vitamin D, and the gross reproduction rate ( GRR ) is 604.8 offspring. L. biplagiata consumed 430 # 42
aphids ( average # SD ) during the larval phase. The average ingestion rate for an grownup during the Trst
25 vitamin D ( aged 14D38 vitamin D from birth ) is 1,548 # 118 aphids. The average ingestion for an older grownup ( aged
60D119 vitamin D from birth ) is 1,319 # 1,259 aphids. When the endurance rate is taken into history, the net
ingestion rate is 3,022 aphids per person during the entire life span. The transmutation rate from
prey population to predator progeny is 10.4. The relationship among GRR, R0, and the preadult
endurance rate ( La ) is proven as R0 # la # GRR # GRR. However, when using the female age-speciTc
life tabular array to a two-sex population, due to the difTculty in finding the preadult mortality of the
females, the deliberate age-speciTc endurance rate and fruitfulness are perchance wrong and accordingly
the relationship among GRR, R0, and Las besides may be wrong.
KEY WORDS Life tabular array, predation, Lemnia biplagiata, Aphis gossypii
Lemnia biplagiata ( Swartz ) ( Coleoptera: Coccinellidae )
is a common predatory ladybug in Taiwan and
mainland China ( Yao and Tao 1972 ) . Its quarry includes
cotton aphid, Aphis gossypii ( Glover ) ; green Prunus persica
aphid, Myzus persicae ( Sulzer ) ; and other Homoptera
( Tao 1990 ) . L. biplagiata has been studied as a biological
control agent in India ( Saharia 1980 ) and China
( Deng et al. 1987 ) . In the former USSR, it was imported
from Vietnam for usage in nurseries to command
A. gossypii on Cucumis sativus and M. persicae on Piper nigrums
( Tverdyukov et al. 1993 ) . The population ecology of
L. biplagiata, nevertheless, remains mostly unknown.
Life table surveies are cardinal to population
ecology. A life tabular array gives the most comprehensive
description of the survivorship, development, and reproduction
of a population. The theory and methods
of the life tabular array are discussed in most ecology text editions
( Monetary value 1997, Ricklefs and Miller 1999 ) . The
aggregation of life tabular array informations for related species at different
trophic degrees in a nutrient concatenation is a basic and
of import undertaking for preservation ( Bevill and Louda
1999 ) and pest direction ( Naranjo 2001 ) . Knowledge
of the life tabular array of both marauder and quarry is
necessary for the mass raising and practical application
of a natural enemy to biological control systems
( Chi and Getz 1988, Chi and Yang 2003 ) . However,
most of the traditional female age-speciTc life tabular arraies
( Lewis 1942, Leslie 1945, Birch 1948 ) ignore the male
population and the phase distinction. They can non
take into history the variable predation rate among
phases and the predation rate of the male. To take the
variable developmental rates among persons and
both sexes into consideration, Chi and Liu ( 1985 ) and
Chi ( 1988 ) developed an age-stage life tabular array theory.
Because fluctuation in developmental rate among persons
and between sexes in a natural population is a
normal happening ( e.g. , Fig. 2 of Chi 1988, Fig. 3 of
Liu et Al. 1997, and Fig. 2 of Liu and Stansly 1998 ) , an
age-stage structured theoretical account aids take the fluctuation in
the predation rate and the survival rate of persons
of the same age but different phase into consideration.
By utilizing the age-stage, two-sex life tabular array, Chi and Yang
( 2003 ) described the life tabular array and stage-speciTc predation
rate of the marauder Propylaea japonica Thunberg
( Coleoptera: Coccinellidae ) fed on M. persicae.
In this article, we use the age-stage, two-sex life tabular array
theory to analyse the life history informations and predation
rate of L. biplagiata Federal on A. gossypii to integrate
1 Department of Applied Zoology, Taiwan Agricultural Research
Institute, Wufeng 413, Taichung. Taiwan, Republic of China.
2 Corresponding writer: Lab of Theoretical Ecology, Department
of Entomology, National Chung Hsing University, Taichung
402, Taiwan, Republic of China ( e-mail: hsinchi @ dragon.nchu.
edu.tw ) .
0013-8746/05/0475D0482 $ 04.00/0 # 2005 Entomological Society of America
the variable developmental rates among persons
and the male population. Furthermore, we mathematically
turn out the relationship among gross reproduction
rate, net reproduction rate, and preadult survivorship.
Materials and Methods
Life Table Study. L. biplagiata was originally collected
in the guava grove of Taiwan Agricultural
Research Institute ( Taichung, Taiwan ) in 1996 and
has later been reared on A. gossypii on Cucumis
melo L. in the research lab for 39 coevalss. For
the life tabular array survey, L. biplagiata were kept in a growing
chamber ( 25 # 1 # C, 70 # 10 % RH and a photoperiod
of 12:12 [ L: D ] H ) for one coevals. One hundred
eggs laid by 20 braces of grownups within a 1-d period were
collected in a plastic box ( 7 by 5 by 3 cm3, with a Tne
mesh nylon cyberspace covering for airing ) . The box was
kept in a growing chamber under the same conditions.
Hatched larvae were moved daily to single raising
boxes, and 140D200 A. gossypii of assorted phases kept on
a foliage of C. melo were supplied as nutrient. When grownups
emerged, the females and males were paired, and
# 400 aphids of assorted phases on a foliage of C. melo were
supplied. In the raising box, two pieces of plastic tubings
( # 1.2 centimeter in diameter, 3 centimeter in length, made from
plastic pipette tubings ) were offered for oviposition ;
little petri dishes ( 3 centimeter in diameter ) with moistened
cotton were used for H2O supply. The fruitfulness and
endurance were recorded daily until the decease of each
single.
Depredation Rate Study. To provide L. biplagiata with
A. gossypii of the same age, 30 grownups of A. gossypii were
set on single foliages of C. melo. After 1 vitamin D, grownup
aphids were removed. The newborn aphids were kept
on the foliages for 3 d. Using this technique, 3-d old
aphids were obtained for the predation survey. Before
a foliage was used in the predation survey, the figure of
aphids was recorded. For the survey of the predation
rate by larvae, 30 larvae of L. biplagiata hatched on the
same twenty-four hours, aged 3-d from birth, were moved into single
rise uping boxes, and were given a foliage of C. melo
with 140D200 aphids daily. After 24 H, the lasting
aphids were counted, the predation rates recorded,
and the larvae of L. biplagiata were transferred to new
rise uping boxes with another 140D200 aphids. This continued
until all larvae pupated. When grownups emerged,
the sex of each person was recorded. Because each
larva was kept in an single raising instance during the
larval phases, the day-to-day predation rate could be recorded
for each person. For the survey of the predation
rate by immature grownups, 15 braces of freshly emerged
grownups ( aged 14 vitamin D from birth ) were collected, paired,
and set into single raising boxes. A foliage of C. melo
with 300D400 aphids was supplied daily. The lasting
L. biplagiata were transferred to new rise uping boxes,
and the endurance and predation rates were recorded
daily for the following 25 d. For the predation rate by older
grownups, we collected 15 braces of 46-d-old grownups, aged
60 vitamin D from birth, and paired them in rise uping boxes with
3-d-old aphids. The endurance and predation rates were
recorded until the decease of all persons. Because the
grownups were kept as braces, we ignored the difference
between sexes, and one-half of the day-to-day predation rate
of a brace was assigned to both male and female as long
as both sexes remained alive. If one sex of a brace died,
the day-to-day predation rate was assigned to the lasting
single.
Life Table Analysis. The natural life history informations of all
persons of this survey were pooled and analyzed
harmonizing to the age-stage, two-sex life tabular array ( Chi and
Liu 1985 ) and the method described by Chi ( 1988 ) .
The agencies and standard mistakes of the population parametric quantities
were estimated utilizing the Jackknife method
( Sokal and Rohlf 1981 ) . To ease natural informations analysis,
life table analysis, and the Jackknife method, a userfriendly
computing machine plan, TWOSEX-MSChart ( Chi
2004 ) , was designed in Visual Basic for the Windows
operating system. It is available at hypertext transfer protocol: //140.120.197.
173/Ecology/download/TWOSEX-MSChart.zip ( National
Chung Hsing University, Taiwan ) and hypertext transfer protocol: //
nhsbig.inhs.uiuc.edu/wes/chi.html ( Illinois Natural
History Survey, Urbana, IL ) . The age-stage speciTc
endurance rate ( sxj ) ( where ten is the age and J is the phase ) ,
age-stage speciTc fruitfulness ( fxj ) , age-speciTc endurance
rate ( sixty ) , age-speciTc fruitfulness ( maxwell ) , and population
parametric quantities ( R, intrinsic rate of addition ; # , Tnite rate
of addition ; R0, net reproduction rate ; and T, the mean
coevals clip ) are calculated consequently. The
meangeneration clip is deTned as the clip length that
a population needs to increase to R0-fold of its size
( i.e. , erT R0 or # T R0 ) at the stable age-stage
distribution.Themeangeneration clip is calculated as
T InR0/r.
Consequences and Discussion
Of 100 eggs used at the beginning of the life tabular array
survey, 62 eggs hatched successfully. There are four
instars. The agencies of developmental periods for each
developmental phase, length of services for grownup male and
female, and female fruitfulness of L. biplagiata are given
in Table 1. The entire developmental period for preadult
phases was 14.1 vitamin D, whereas grownups lived every bit long as
105.7 d. A maximum day-to-day fruitfulness of 74 eggs was
observed. For the entire life span, a maximum fruitfulness
of 1,711 eggs has been recorded for a individual female.
The average female fruitfulness of L. biplagiata is 939.1
eggs.
Table 1. Developmental clip, grownup length of service, and fruitfulness of
L. biplagiata at 25 Ninety
Parameter Stage n Mean SEM
Developmental clip ( vitamin D ) Egg 62 3.18 0.08
First instar 60 1.97 0.02
Second instar 55 1.15 0.05
Third instar 55 1.73 0.06
Fourth instar 54 2.09 0.07
Pupa 54 4.02 0.02
Entire preadult 54 14.13 0.13
Adult length of service ( vitamin D ) Adult male 23 105.6 6.50
Adult female 31 105.7 3.54
Fecundity ( F ) ( offspring ) Adult female 31 939.1 67.4
476 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 98, no. 4
The sxj gives the chance that a neonate will
survive to age ten and phase J ( Fig. 1 ) . There are important
convergences during the developmental period. Under
controlled conditions, both male and female can
survive long periods, and there is no lessening in endurance
rates for either male and female for # 60 500 postemergence.
If the natural informations were analyzed utilizing a traditional
female age-speciTc life tabular array ( Lewis 1942, Leslie 1945,
Birch 1948 ) , it would be impossible to see the
alterations of the phase construction, because traditional life
tabular arraies ignore male persons and the variable developmental
rate among persons ( i.e. , the phase distinction ) .
Manyresearchers have ignored the variable
developmental rate among persons and have
used the rounded agencies of each phase to split the life
span into nonoverlapping phases ( e.g. , Fig. 8.5 of Pianka
1994, 153 ; Table 4D4, 4D5, 6D14, and 6D12 of
Carey 1993 ) . These processs necessarily result in
mistakes in life table parametric quantities. Chi ( 1988 ) gave a
comprehensive treatment on the jobs and mistakes
due to disregarding phase imbrication.
The figure of offspring produced by single L.
biplagiata of age ten and phase J per twenty-four hours is shown with
fxj in Fig. 2. Because lone females reproduce, there is
merely a individual curve fx7 ( i.e. , female is the 7th life
Fig. 1. Age-stage speciTc endurance rate of L. biplagiata at 25 # C.
Fig. 2. Age-speciTc endurance rate ( sixty ) , age-stage speciTc fruitfulness ( fx7 ) of the female phase ( the 7th life phase ) ,
age-speciTc fruitfulness ( maxwell ) , and the age-speciTc pregnancy ( lxmx ) of L. biplagiata at 25 # C.
July 2005 YU ET AL. : LIFE TABLE OF L. biplagiata 477
phase ) . The sixty, maxwell, and age-speciTc pregnancy ( lxmx )
besides are plotted in Fig. 2. It shows that there are
periodic generative extremums about every 20 vitamin D,
and these may be due to cyclicity of the reproductive
physiology. Abou Zied et Al. ( 2003 ) found a periodic
reproduction in the Australian sheep blowsy,
Lucilia cuprina ( Wiedemann ) ( Diptera: Calliphoridae ) .
Many research workers ignore the differences in preadult
development among persons and form fruitfulness
informations based on grownup age ( Fig. 3 of Liu and Stansly
1998, Fig. 1 of Calvitti and Remotti 1998, Fig. 2 of Tsai
1998, Fig. 3 of Riudavets and Castan? vitamin E? 1998, Fig. 1 of
Hansen et Al. 1999, Fig. 4 of Joyce et Al. 1999, Table 3
of Havelka and Zemek 1999, Fig. 1 of Abdel-Salam and
Abdel-Baky 2001, Fig. 2 of Chabi-Olaye et Al. 2001, Fig.
2 of Tsai and Wang 2001, Fig. 4 of Greenberg et Al.
2003, and Stenseng et Al. 2003 ) . For illustration, Liu and
Stansly ( 1998 ) observed a signiTcant fluctuation in the
developmental rate among persons of Bemisia argentifolii
Bellows & A ; Perring ( Homoptera: Aleyrodidae )
( Fig. 2 in their article ) but ignored the variable
developmental rate and organized the survivorship
and fruitfulness based on grownup age ( Fig. 3 in their
article ) . Headrick et Al. ( 1999 ) reported the preimaginal
developmental clip for female Eretmocerus eremicus
Rose & A ; Zolnerowich ( Hymenoptera: Aphelinidae )
assailing B. argentifolii on cotton ranged from 16
to 27 vitamin D ( Table 3 of Headrick et Al. 1999 ) . Their computations
of the day-to-day oviposition, nevertheless, were
based merely on grownup age. Because the Trst reproduction
yearss of single females really vary harmonizing to
the scope of the grownup outgrowth, disregarding the differences
in preimaginal development consequences in mistakes
in the fruitfulness curve, and, finally, in mistakes in the
population parametric quantities. Therefore, if the age-speciTc endurance
rate is constructed based on the agencies of nonoverlapping
phases and the age-speciTc fruitfulness is
constructed based on the grownup phase, the curves will
be different from the sixty and maxwell that are based on the
age counted from the birth of the person. If the life
history natural informations are organized harmonizing to the theoretical account
of Caswell ( 1989, p. 83 ) , it will ensue in the same
job as utilizing grownup age, because CaswellOs theoretical account
classiTes persons by age within phases. Chi ( 1988 )
discussed explicitly the differences between the traditional
female life tabular array and the age-stage, two-sex life
tabular array.
When informations of all 100 persons of L. biplagiata in
this survey are used to cipher the population parametric quantities,
the R is 0.1565 vitamin D # 1, # is 1.1694 vitamin D # 1, R0 is 291.1
progeny, meangeneration clip ( T ) is 36.3 vitamin D, and gross
reproduction rate ( GRR ) is 604.8 offspring. We besides
estimated the agencies and standard mistakes of the population
parametric quantities by utilizing the Jackknife method
( Sokal and Rohlf 1981 ) . The estimated R of L. biplagiata
is 0.1570 # 0.0069 500 # 1 ( average # SEM ) , # is
1.1700 # 0.0080 500 # 1, R0 is 291.1 # 48.3 progeny, T is
36.2 # 1.0 vitamin D, and GRR is 604.8 # 85.3 offspring. There
are minor differences between the consequences estimated
by utilizing the Jackknife method and that calculated by
pooling informations of all persons. Discussion refering
the general application of the Jackknife method can be
found in standard statistics books such as Sokal and
Rohlf ( 1981 ) . Discussion on speciTc applications of
the Jackknife method on population parametric quantities can
be found in Meyer et Al. ( 1986 ) . Perdikis and Lykouressis
( 2002 ) reported R, R0, and T of the predatory
bug Macrolophus pygmaeus Rambur ( Hemiptera: Capsidae )
at 27.5 # C of 0.0981 500 # 1, 49.94, and 46.62, severally.
Harmonizing to life table theory, T ln R0/r.
Because the consequences of Perdikis and Lykouressis ( 2002 )
showed that T # ln R0/r, their informations may be in mistake.
Similar mistakes are found in Morales-Ramos and Cate
( 1992 ) and Urbaneja et Al. ( 2001 ) . As proven by Chi
( 1988 ) for the two-sex life tabular array, the relationship between
R0 and average female fruitfulness, F, is given as
follows:
R0 # F # Nf/N [ 1 ]
whereNis the entire figure of persons used for life
tabular array survey and Nf is the figure of female grownups. In
this survey, the value of N, Nf, F, and R0 for L. biplagiata
is 100, 31, 939.1, and 291.1, severally. Their relationship
is consistent with equation 1. Seal et Al. ( 2002 )
studied the life tabular array of Catolaccus hunteri ( Hymenoptera:
Pteromalidae ) . In their study, GRR was
291.60 and R0 was 216.84 when reared on black-eyed pea
weevil, Callosobruchus maculatus ( F. ) , at 25 # C ( Table
3 of Seal et Al. 2002 ) . In Lee and Ahn ( 2000 ) , GRR and
R0 for Amblyseius womersleyi ( Schicha ) ( Acari: Phytoseiidae )
at 24 # C are 20.42 and 12.48, severally ( Table
8 of Lee and Ahn 2000 ) . For a clear apprehension
on the relationship between GRR and R0, we give the
following cogent evidence. In the female age-speciTc life tabular array,
the gross reproduction rate is deTned as follows:
GRR # #
x 0
#
maxwell [ 2 ]
where # is the last age of the cohort. The net reproduction
rate is deTned as follows:
R0 # #
x 0
#
lxmx [ 3 ]
Before the grownup outgrowth, all maxwell values are zero.
Therefore, if the grownup emerged on age a, so
#
x 0
a # 1
lxmx # 0 [ 4 ]
R0 # #
x a
#
lxmx [ 5 ]
and
GRR # #
x a
#
maxwell [ 6 ]
Because sixty is a drone diminishing sequence of age,
it gives
478 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 98, no. 4
1 # la # La
1 # La
2 # . . . # fifty # [ 7 ]
Therefore, it follows that
R0 # #
x a
#
lxmx # #
x a
#
mx # GRR [ 8 ]
The utmost instance of R0 GRR exists if and merely if sixties
1 when maxwell # 0. Because sixty lessenings with age and
Tnally diminishes to zero, it is safe to anticipate that
R0 # GRR [ 9 ]
and
#
x a
#
lamx #
x a
#
lxmx # R0 [ 10 ]
Therefore, if la # 1 ( i.e. , there is preadult mortality ) , it gives
R0 # #
x a
#
lxmx # #
x a
#
lamx # La #
x a
#
mx # #
x a
#
mx # GRR
[ 11 ]Conclusively, the following relationship exists for both
the age-stage, two-sex life tabular array and the female agespeciTc
life tabular array:
R0 # la # GRR # GRR [ 12 ]
However, when using the female age-speciTc life
tabular array to a two-sex population, due to the difTculty in
finding the preadult mortality of the females, the
calculated age-speciTc endurance rate and fruitfulness are
perchance incorrect and accordingly the relationship
among GRR, R0, and Las besides may be wrong. In the
study of Seal et Al. ( 2002 ) , the age-speciTc endurance
rate at grownup outgrowth is signiTcantly # 0.5 at 25 # C,
i.e. , la # 0.5 ( Fig. 1 of Seal et Al. 2002 ) . IfGRR 291.60,
so the following relationship should be:
R0 # la # GRR # 0.5 # 291.60 # 145.8
Therefore, if the GRR is 291.60 as reported in Seal et Al.
( 2002 ) , so R0 must be # 145.8. Their consequences, R0
216.84 and GRR 291.60, are perceptibly inconsistent
with the above-named cogent evidence ( equation 12 ) . In the
study of Lee and Ahn ( 2000 ) , the mortality of the
entire immature phase of A. womersleyi is 60 % at 24 # C
( Table 1 of Lee and Ahn 2000 ) , i.e. , la 1 # 0.6 0.4.
If the GRR 20.42, so it must give
R0 # la # GRR # 0.4 # 20.42 # 8.168
Obviously, R0 must be # 8.168. Therefore, their consequences,
R0 12.48 and GRR 20.42, are seemingly inconsistent
with the above-named cogent evidence ( equation
12 ) . The above-named two illustrations demonstrate
an extra job that may ensue from the application
of the age-speciTc female life tabular array to stagestructured
populations. Detailed treatments on the
jobs are given in Chi ( 1988 ) and Chi and Yang
( 2003 ) . The GRR for L. biplagiata is 604.8. The R0 is
291.1. The La is 0.54. Our consequences are consistent with the
relationship as proven in equation 12. Lemos et Al.
( 2003 ) , who reported the GRR, R0, and survival rate to
maturity for Euborellia annulipes ( Lucas ) ( Dermaptera:
Anisolabididae ) , besides had consequences consistent
with equation 12. In equation 2, GRR is a simple summing up
all maxwell. At the beginning of reproduction, maxwell is
calculated based on the fruitfulness of all lasting females.
However, at older ages, maxwell is by and large calculated
based on the fruitfulness of a few surviving females,
sometimes even a individual female. Therefore, maxwell of the
older ages contribute signiTcantly less to the population.
Because GRR ignores the different weight of maxwell
of different age, it should be interpreted with cautiousness.
However, equation 12 can be surely used as a
standard for double-checking the statistical consequences in
life table surveies.
The age-speciTc predation rate ( kx ) during the larval
phase of L. biplagiata is shown in Fig. 3. The agespeciTc
predation rate is the average figure of aphids
consumed by L. biplagiata of age ten. By taking the
endurance rate into consideration, Chi and Yang ( 2003 )
deTned the age-speciTc net predation rate ( qx ) as the
leaden figure of quarry consumed by marauder of
age ten and it is calculated as follows:
qx # lxkx
The qx besides is plotted in Fig. 3. The consequence shows that
the larval predation rate increased signiTcantly from
age 3 to 8 d. Then, because some larvae entered the
pupal phase, the predation rate decreased on age 9 vitamin D.
During the full larval phases, an person of L.
biplagiata consumed 430 # 42 ( average # SD ) aphids.
The age-speciTc predation rates and age-speciTc cyberspace
predation rate during the Trst 25 vitamin D of the grownup phase
( aged 14 to 38 vitamin D from birth ) are shown in Fig. 4. It
increased signiTcantly with the age for # 15 vitamin D and so
decreased for a few yearss. In comparing with the
fruitfulness curve ( Fig. 2 ) , a similar periodic predation
rate of 20 vitamin D can be observed. The entire mean ingestion
rate during the Trst 25 vitamin D of the grownup phase
is 1,548 # 118 aphids. The age-speciTc predation rates
and age-speciTc net predation rate for older grownups
( aged 60 to 119 vitamin D counted from birth ) are shown in
Fig. 5. For older grownups, the predation rate decreased
with age and no obvious cyclicity of predation rate
is observed. The entire ingestion rate for an older
grownup is 1,319 # 1,259 aphids with a coefTcient of
fluctuation ( CV ) of 95 % . The high CV value is due to the
signiTcant fluctuation in endurance in older grownups. Because
experiments on predation rate are really time-consuming,
we did non roll up informations for the age interval from
39 to 59 d. Alternatively, we calculated the mean of the day-to-day
predation rate for the age intervals from 29 vitamin D to 38 vitamin D
and from 60 vitamin D to 69 vitamin D ( counted from birth ) , and so
we used it as the estimated predation rate for the age
interval from 39 to 59 d. Chi and Yang ( 2003 ) calculated
the net predation rate ( C0 ) as follows:
C0 # #
x 0
#
kxlx
July 2005 YU ET AL. : LIFE TABLE OF L. biplagiata 479
where # is the last age of the population and kx is the
age-speciTc predation rate. In this survey, because the
informations on predation is recorded merely to age 119 vitamin D, we
obtained a net predation rate C0 3,022 for # 119.
Chi and Yang ( 2003 ) showed that the part of
older marauders to the net predation rate is minor.
Because of the low predation rate after age 120 vitamin D, we
ignore the predation rate from age 120 to 152 d. Chi
and Yang ( 2003 ) deTned the transmutation rate from
prey population to predator offspring as follows:
Qp #
C0
R0
.
The Qp for L. biplagiata Federal on A. gossypii is 10.4. This
agencies that L. biplagiata demands 10.4 persons of 3-dold
A. gossypii for the reproduction of one marauder
egg. This Qp gives an demographic appraisal for the
relationship between the reproduction rate and predation
rate of marauder. Sahayaraj and Paulraj ( 2001 )
reported that the predation rate of Rhynocoris marginatus
F. ( Heteroptera: Reduviidae ) on Spodoptera
litura F. ( Lepidoptera: Noctuidae ) larvae increased
with phase. Xia et Al. ( 2003 ) studied the functional
responses of Coccinella septempunctata L. ( Coleoptera:
Coccinellidae ) fed on A. gossypii and found
signiTcant difference in predation rates among marauder
phases. The age-stage variableness of predation of
marauder and that of exposure of quarries have been
observed by many research workers ( Isenhour and Yeargan
1981, Clements and Yeargan 1997, Hu and Frank 1997,
Chi and Yang 2003 ) . All of these facts about stagespeciTc
predation rates could non be taken into ac-
Fig. 3. Age-speciTc predation rate ( kx ) and age-speciTc net predation rate ( qx ) of larva of L. biplagiata at 25 # C ; the age
is counted from birth.
Fig. 4. Age-speciTc predation rate ( kx ) and age-speciTc net predation rate ( qx ) of immature grownup of L. biplagiata at 25 # C ;
the age is counted from birth.
480 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 98, no. 4
count in simple predation theoretical accounts without age or phase
construction, e.g. , LotkaDVolterra predation theoretical account and its
derived functions. Actually, Hassell ( 1978 ) had pointed out
that the inclusion of the marauder and prey age construction
is an of import measure in understanding predatorD
quarry relationship. Because most carnal species are
age-structured or age-stage-structured, farther accretion
of the cognition of the stage-speciTc predation
rate and stage-structured life tabular array will be necessary
for a proper mold of predatorDprey
kineticss.
Recognitions
We thank Y. H. Yeh for aid with the experiments.
We are thankful to Cecil L. Smith for generous aid in rectifying
our English.Wethank the editor and two anon.
referees for valuable remarks that greatly improved the
manuscript.
