Juma Khan1 and Mehmood Ali Noor2,3*
1Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, Riyadh, Kingdom of Saudi Arabia 2Institute of Crop Science, Chinese Academy of Agricultural Sciences, Key Laboratory of Crop Physiology and Ecology, Ministry of Agriculture, Beijing 100081, China 3Department of Agricultural Extension and Rural Society, College of Food and Agriculture Sciences, King Saud University, Riyadh, Kingdom of Saudi Arabia
Received: 01 December, 2016; Accepted: 28 December, 2016; Published: 30 December, 2016
Mehmood Ali Noor, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Key Laboratory of Crop Physiology and Ecology, Ministry of Agriculture, Beijing 100081, China, E-mail:
Khan J, Noor MA (2016) Outline of Biological Effects, Fecundity, Eclosion and Lifespan on Adult Tropical Warehouse Moth, Cadra cautella (Lepidoptera: Pyralidae) by Using Sex Ratio. Int J Agric Sc Food Technol 2(1): 035-040. DOI: 10.17352/2455-815X.000012
© 2016 Khan J, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Cadra cautella; Pyralidae; Lepidoptera; Fecundity; Eclosion; Lifespan; Sex ratio; Biology
Tropical warehouse moth Cadra cautella Walker, 1863 (Lepidoptera: Pyralidae) is a major pest of stored food products worldwide. It was originated from the tropics and subtropics but it disperses through imported food cargoes. The biological performance, fecundity, eclosion (emergence of larvae from egg or adult from pupae) and lifespan of adult Tropical warehouse moth at different sex ratio (female: male) was studied under constant conditions. Fecundity and eclosion of larvae was investigated by five treatments: sex ratio (1F:1M, 2M, and 3M), (1M: 2F, 3F) and one more treatment of separated male and female as a control for lifespan. Eclosion of adult was measured by collecting 350 pupae in different aged 200 male and 150 female. 1M: 3F treatment have the highest number of eggs and the least percentage of hatching to larvae and 2M: 1F and 3M: 1F treatments non-significantly behaved between them having the least number of total eggs and the maximum number at total eggs per female, in both have a larger percentage of hatching to larvae respectively. Lifespan of male was significant with all treatments except 1M: 3F and lifespan of female was non-significant with all treatments. Eclosion of adults calculated as three levels of normal, abnormal and not emerged; for female 42% normal, 5% abnormal, 53% not emerged out of 150 pupae and for male 20% normal, 10% abnormal 70% not emerged out of 200 pupae, was observed.
Tropical warehouse moth; almond moth; cocoa moth; fig moth Cadra cautella Walker, 1863 (Lepidoptera: Pyralidae) is a major pest of stored food products worldwide . It is originated from the tropics and subtropics but it disperses through imported food cargoes . This dangerous pest of stored products is extremely found in packaged food . A very serious cosmopolitan stored product pest infesting a wide variety of hosts such as maize, wheat, and other grains in stores. This specie is a poly-phagous pest that feeds on dried fruits, beans, nuts, bananas, groundnuts, dried cocoa, dried grains, pulses, tobacco, and coconut. Infestation is mainly post-harvest .
Sex ratio means male to female rate in population when male and females in a ratio of 1:1 that a stable strategy in a population of diploid organisms including insect . Sex ratio for a population is an indicator of mating intensity . Almost equal sex ratio for males and females exists in many animal species including insects [5,7-9]. The mating system have strong effects on mechanism and sex ratio in population and also may be have effects in properties of sex ratio in older ages . A favor in sex ratio might occur because of many factors such as local mate competition (LMC) [10,11], birth, death and migration rates , edaphic factors , micro-organism infection  and inbreeding .
Reproduction of insects is also affected by the females mating frequency during her reproductive period . C. cautella is a polyandrous, and its initial mating starts on the first day after emergence and further takes place on following days . Present study was carried out to explore the biological performance of adult C. cautella at various sex ratios and pairing duration was also investigates for females and males kept together.
Materials and Methods
To fulfill the objectives of study, a laboratory experiment was conducted at the Economic Entomology Research Unit Laboratory, Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, Riyadh, Kingdom of Saudi Arabia. A colony of tropical warehouse moth was reared on a modified diet composed of a mixture of 1 kg of crushed wheat, hen and broiler poultry feed (each 1.5 kg), and 400 ml of glycerine (Al-azab 2007). Clear-plastic, 1.3-L containers (18, 12, and 6 cm) were used for rearing. The colony and experiments were maintained at 25°C and 65% relative humidity, with a photoperiod of 16:8 L: D inside an incubator (Steridium i500, Queensland, Australia). Only newly emerged adults were used for experiments. To obtain them, pupae were removed from the colony and kept in 60-mL transparent plastic cups (7 cm diameter, 2.5 cm tall). Insects were sexed at the pupal stage and adults of each sex were kept in separate containers. For the sex-ratio experiment, groups of newly emerged adults at different sex ratios were confined until their deaths in a 310-mL plastic jar (7 cm diameter, 8 cm tall), positioned upside down. Fiber screen (1 mm2) was used to cover the rim of the jar to let eggs pass down to the 8-cm diameter plastic Petri dishes, which acted as a lid for the jar. Adults were fed by a piece of cotton soaked in sugar solution (10% w/v) that was clipped on the wall of each jar. Air circulation inside the jar was increased by seven small needle holes in the container’s walls. 5 replications of the sex-ratio experiment were performed on six treatments: normal sex ratio (1 Female: 1 Male), two male-bias sex ratios (1F:2M and 1F:3M), two female-bias sex ratios (2F:1M and 3F:1M), and virgin females alone (1F:0M) and virgin male alone also. The number of eggs, their hatching rate, and the incubation period were determined. Also, total lifespan for both males and females were recorded for the experiment. All data were obtained by daily observations starting from the time females and males were confined in the plastic jar until they died. All data analysis was conducted using SPSS version 18.
Results and Discussion
Impact of sex ratio on the fecundity of adult tropical warehouse moth
All treatments, started laying eggs in 24 hours after mating except only one treatment (2F:1M) it began setting the eggs after 48 hours. The maximum number of eggs deposition was in the 3rd, 4th and 5th day respectively (Table 1)
When we compare between total number of eggs and total eggs per one female, it is clear that treatment 3F:1M have the maximum number of total eggs and 1F:1M have the least number of total eggs and 3M: 1F have the maximum number of total eggs per female and 2F:1M have the least number of total eggs per female. It means that the population have a lot of female, it can deposit the more eggs but the minimum number of eggs per one female (Figures 1,2). On other hand the population have a lot of male, it can give the optimum number of eggs but the maximum no. per one female (3M: 1F, 2M: 1F) respectively (Figures 1,2).