Effects of temperature increase caused by larval metabolism on the reproduction of Anagasta kuehniella (Lepidoptera: Pyralidae), a factitious host for Trichogramma

ABSTRACT

Many biological-control programmes, particularly those using egg parasitoids of the genus Trichogramma, involve rearing control agents on eggs of factitious hosts such as Anagasta kuehniella (Zeller). The objective of this study was to improve procedures for mass rearing of A. kuehniella, by determining the optimal population density in rearing trays, and evaluating the effects of metabolically induced temperature increase on reproduction and development. During the fourth and fifth instars, the temperature in trays increased 7–9°C, depending on larval density. Maximum egg production was obtained in trays inoculated with 10,800 eggs. Females and eggs obtained from this density were heavier than those reared at higher densities. Maintaining the temperature inside the rearing trays at 25°C increased egg production by up to 8 g per tray. However, both the heat from larval metabolism and the larval density significantly reduced the fecundity of A. kuehniella.

KEYWORDS:

• Mass rearing
• metabolic heat
• fecundity

Acknowledgements

We thank Janet W. Reid, JWR Associates, for the English revision, and the reviewers for suggestions and criticisms.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We thank the National Council of Technological and Scientific Development (CNPq) and the National Institute of Semiochemicals in Agriculture (INCT) for financial support.