The Biology of Lepidoptera Infesting Stored Products, With Special Reference to Population Dynamics

Abstract

Summary I. This review provides a background to those aspects of the biology and behaviour of Lepidoptera infesting stored products which may be important in terms of population dynamics. 2. The general biologies of four common species of Phycitid moth are described. 3. Both the fecundity and the fertility of the adult can be influenced by the diet of the female, the size of the female, the numbers of adults per unit area and a variety of environmental factors. 4. Egg mortality may be caused by sterility or cannibalism. Larval mortality may be caused by starvation or cannibalism. Crowding leads to emigration, reduced size and extended developmental period. Pupal and adult mortalities are of minor importance. Pupae may suffer developmental disorders and adults are killed by spiders and lost by emigration. 5. Parasitoids, predators and diseases, which also contribute to mortality of eggs, larvae, pupae and adults, are described. 6. The importance of planning and sampling in order to obtain detailed data on populations are discussed, together with the analysis of the data. 7. It is shown that Lepidoptera which infest stored products and the parasitoids associated with them have proved convenient experimental tools for the elucidation of certain aspects of population dynamics. A small number of studies have succeeded in identifying the main factors or processes responsible for fluctuation or regulation of the densities of these moths.

Effect of storage duration on the stored pupae of parasitoid Bracon hebetor (Say) and its impact on parasitoid quality

“…Another study indicated that female: male sex ratio was 1:3.9 (Ahmed et al, 1985). Male biased sex ratio was obtained in the present which explained that the male eggs hatched before than the female eggs, and the male larvae would have a better survivability due to sufficient food (Benson, 1973).…”

Determining Host Suitability of Pecan for Stored-Product Insects

“…Because P. interpunctella succeeded in developing adults on nutmeats and immatures were found inside in-shell pecans, this indicates a possible inability of adults to pupate in or emerge properly from the pecan shell. Low numbers of adult P. interpunctella recovered throughout the later intervals of the experiment may possibly be attributed to the brittle adult corpses being destroyed by larval competition, wanderingstage activity, web-production of subsequent caterpillar generations, crowding, or cannibalism within the conÞnes of jars (Benson 1973, Briggs et al 2000. In addition, low adult numbers may be because of the pecan "meal" produced by feeding being of inadequate size to complete reproduction in P. interpunctella (Sambaraju and Phillips 2008).…”

Assessment of the Influence of Artificial Dietary Supplements on Aspects of Biology of Adult Cocoa Moth, Ephestia Cautella

“…Although adult E. cautella has non-feeding adults with functional mouthparts that are used to drink liquids [3,4,5], access to drinking water prior to and after mating during adulthood in almond moths (cocoa moths) increased longevity in males and females, and also resulted in an increase in the total number of fertilized eggs [3].. This study had a contrary result to what [3] reported on the effects of water on longevity of both virgin and mated adults (male and female), as access to water significantly (p = 0.05) reduced the longevity of adults of E. cautella treated before and after mating.…”

“…Many pyralid moths were reported to have non-feeding adults [2]. E. cautella, a typically indoor pest of stores and warehouses and has a non-feeding adult with functional mouthpart modified for sucking liquid [3,4,5]. Food quality and availability will affect the lifehistory investment in any organisms [6].…”

“…Stored-product moths and beetles are often used as model species in laboratories for life-history and matingstrategy studies in insects [9,10,11]. These insects are cosmopolitan, are able to inhabit indoor facilities and are adapted to live on abundant food commodities with either good or poor quality [4,12]. The cocoa moth's natural food media (cocoa beans, dried fruits, nuts, grains etc) require low moisture content for proper storability; adults should therefore be highly dependent on water for reproductive investments such as gonads development and gamete production, in connection to adult moth's attractiveness to water [7,8].…”