Biology and Demography of Ephestia kuehniella (Pyralidae: Lepidoptera)
80
1
60
0.75
Survivorship
Abstract Ephestia kuehniella z. is a major stock pest not only in Iran but also around the world which attacks a large number of products in stocks and damages them. Flour moth (E. kuehniella) is very important and is used as a leading laboratory host in breeding and mass production of parasitoid wasps of Trichogramma genus and some other predators. Life table of Flour moth was studied at temperature of 25±0.5°C, humidity of 50 ±0.5% and in darkness and flour and yeast as the food. The obtained data were analyzed according to conventional life table. Intrinsic rate of population growth (rm), finite rate of population growth (λ), net reproduction rate (R0), gross reproduction rate (GRR), mean generation time (T), doubling time (DT) were respectively 0.0683 days, 1.0707 days, 133.861 female offspring, 1147 female eggs, 71605 days, and 10135 days.
Egg per female
Z. Moghadamfar1, M. Amir-Mafi2 and H. pakyari1 1- Department of plant protection, faculty of Agriculture, Islamic Azad University, Takestan Branch- Iran,
[email protected]. 2- Sunn pest Research Department, Iranian Research Institute Of Plant Protection, Tehran, Iran
40 20 0
0.5 0.25 0
0 1 2 3 4 5 6 7 8 9 101112131415161718 Adult age (days)
0 1 2 3 4 5 6 7 8 9101112131415161718 Adult age (days)
Key words Ephestia kuehniella , Biology, Demography
Fig. 5. Daily egg production of adult mediterranean flour moth at 25 °C.
Introduction The Mediterranean flour moth, Ephestia kuehniella Zeller, 1879 is a serious cosmopolitan pest of stored products, particularly cereal mills (Rees 2003) and its eggs are used to rear parasitoids and predators for biological control programs (Tavares et al. 1989, Viera et al. 1992). The improvement of mass rearing is dependent on the knowledge of rereproductive capacity and related biological traits. Therfore, the objectives of this study were, to estimate basic demographic parameters that could be used in mass rearing program and control research.
Survivorship of female is given in fig. 6. No females died during the first 3 days. After 7 days about 60% of the original female cohort was alive. Those remaining females continued to live for 10 days. Summary statistics of the adult characteristics are given in table 1. the expectation of life at female eclosion was 8.53 days. Gross and net fecundity were 392 and 295 eggs/female respectively. A female living to her maximum life span laid 90% fertile eggs. Net fertility was 32% less than was gross fecundity. Of this percentage, 22%was due to adult mortality and 10% due to infertility. In short, adult mortality played larger role than infertility in reducing gross reproduction.
Materials and Methods Insect's colonies: E. Kuehniella were reared for 2 generation in metal boxes (30 × 20 × 5 cm) each filled with 1 kg of a standard diet (970 g of wheat flour and 30 g of brewer’s yeast for 250-300 pyralid eggs (Attaran 1996) (Fig. 1). Temperature and relative humidity was maintained in an incubator at 25±0.5⁰C , 50±% RH and in darkness (Fig. 2). Life Table: For the life table study, 100 eggs laid within 4 h randomly, were collected from colony by fine brush. Eggs were individually placed on standard diet (2 g) in plastic Petri dishes (5 cm in diameters and 1 cm in depth) (Fig. 3).. All Petri dishes were kept in an incubator under the same conditions as described above. The survival and developmental stage were checked daily. As adult moths emerged, males and females were paired in plastic vials (5.5 cm in diameters and 5 cm in depth) that its bottom end was covered by fine mesh net (Fig. 4) and provided with sugar water (10%). The daily survival of each individual and fecundity of each female fecundity were recorded daily until the death of all individuals. Population parameters, life and fertility tables were estimated following the methods described in Carey (1993). Fig. 2
Fig. 6. Age specific survival.
Table. 1. Summary statistics of adult life history trait General trait Survivorship
Fecundity
Egg hatch
Fertility
Parameter Expectation of life at eclosion Gross fecundity Net fecundity mean eggs per day mean age of fecundity Gross hatch Net hatch mean age hatch Gross fertility Net fertility mean fertile eggs per day mean age of fertility
Value 8.53 (days) 392 (eggs) 295 (eggs) 23 (eggs) 5.12 (days) 90% 90% 7.5 (days) 353 (eggs) 265 (eggs) 20.7 (eggs) 5.12 (days)
Table. 2. Population parameters GRR
207.8422682 (offspring)
R0
60.10627561 (offspring)
rm
0.063765093 (d-1)
λ
1.065841996 (d-1)
T
64.23756387 (day)
DT
10.87032331 (day)
Fig. 1
Fig. 3
Fig. 4
Results The Mediterranean flour moth, Ephestia kuehniella Zeller, 1879 is an important pest of cereal mills and its eggs are used widely to rear Trichogramma spp. for biological control programs in Iran. Eggs: Eggs are laid singly. They are ellipsoid and white when laid, turning light yellow as embryo develops. The time taken for the eggs to hatch at 25 °C, ranged from 1 to 7 days. The mean developmental time was 4.27±0.11 d. Larvae: Larvae are cream coloured and sparsely covered with long hairs. E. kuehniella have six instars. After hatching enter the infested flour, begin feeding and remain unseen. At 25 °C, mean developmental time of larvae was 46.9±1.96 d. (ranged 35-81 d.). Pupa: E. kuehniella pupate in silken cocoons. Mature larvae crawl to the surface of flour, and spin silk cocoons. Pupae are pale green at the early stage and then turn to reddish brown and at the last day of development pupae become dark in colour. At 25 °C, mean developmental time of pupa was 9.19±0.69 d. Adults: E. kuehniella females are ready to mate and lay eggs when the emerge, but egg production began after 1 day. The number of eggs per female peaked at 3 days, then it decreased steadily from day 4 to 14 and tapered off to zero after this time (Fig. 5).
Population parameters. The intrinsic rate of increase and the net reproductive rate were 0.0.0638 and 60.106, respectively, indicating a daily increase of 6.38 % and a 60-fold increase from generation to generation. The population size was estimated to double in ~11 d., while the mean generation time was 164.23 d.. References ATTARAN, M.R. 1996. Effect of laboratory hosts on biological attributes of parasitoid wasp Bracon hebetor Say. M.S. THESIS, Tarbiat Modarres University, Iran. CAREY, J. 1993. Applied demography for biologists. Oxford University Press, New Yourk. REES, D. 2003. Insects of stored products. CSIRO Publishing, London. 181 pp. TAVARES, J., ANUNCIADA, L., OLIVEIRA, L. and VIEIRA, V. 1989. Produção em massa da Ephestia kuehniella Zeller (Lep., Pyralidae). III - Metodologia para a avaliação da produção de adultos e ovos. Bolm. Soc. port. Ent. 104: 13-24 VIEIRA, V., TAVARES, J. and DAUMAL, J. (1992): Influence des temperatures alternées sur le developpement larvaire d'Ephestia kuehniella Zeller (Lep., Pyralidae). Açoreana .7(3): 471-477.
