Journal of Pest Science (2021) 94, 1091-1103

Sirsha Mitra, D.M. Firake, K.P. Umesh, Prashasti P. Pandey and Sagar Pandit (2021)
Polyphagous caterpillars of Spodoptera litura switch from a trap crop to the main crop, improve fitness, and shorten generation time
Journal of Pest Science 94 (4), 1091-1103
Abstract: Trap crops are used for pulling the pest load from the main crops toward themselves. Here, we report a switching by a polyphagous pest, Spodoptera litura, from trap crop castor to main crop eggplant during its mid-larval development. In the eggplant–castor mixed field, adults oviposit exclusively on castor. However, 3rd and 4th instar castor-grown larvae migrate to eggplants. Host choice assays for adults and larvae conducted in the controlled environment and the nutritional indices of castor and eggplant-feeding larvae revealed that the natural enemies did not influence the host switch. The host switch was rather associated with larvae's enhanced digestion and metabolism. It shortened the development time and increased the eclosion success on eggplant. Mother-selected castor is suitable for the early instars and eggplant is for the later instars, indicating that the host switching was not because of the mother's erroneous host choice but has evolved as an advantageous behavior. S. litura 's ability to switch hosts in the same ontogenic phase and reduce the generation time can contribute to an additional generation within a cropping season and endanger the critical growth stage of fruiting. Our findings support the 'mother knows the best' concept and annex that the larvae can also possess the ability to know the best. Such ability in different ontogenic stages can be fundamental to the exceptional adaptability of species like S. litura.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): D.M. Firake

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Spodoptera litura	Eggplant (Solanum melongena)	India