Natural history of Symmetrischema lavernella (Lepidoptera: Gelechiidae): a moth with two feeding strategies and the ability to induce fruit formation in the absence of pollination.

The moth Symmetrischema lavernella (Chambers) (Lepidoptera: Gelechiidae) has two feeding strategies on its host plant Physalis Linnaeus (Solanaceae): a fruitworm that feeds on developing ovules in a fruit and a budworm that consumes a floral bud. The fruitworm strategy occurs when a neonate caterpillar enters the ovary of a flower bud above a size threshold (~4 mm in Physalis heterophylla Nees), consumes the developing ovules, and pupates in the fruit. In P. heterophylla, occupancy of the ovary by S. lavernella causes fruit development to occur in the absence of pollination, indicating that the caterpillar initiates developmental pathways associated with pollination. The budworm strategy occurs in buds below ~4 mm, involves consumption of the ovary and immature anthers, and results in pupation inside the uninflated calyx. The two strategies co-occur on plants, determined by the sizes of the available buds at the time of oviposition. The most prominent natural enemy of S. lavernella using the fruitworm strategy was the frugivorous caterpillar Heliothis subflexa (Guenée) (Lepidoptera: Noctuidae), also a specialist of Physalis. The larger Heliothis subflexa feeds on the fruit externally, consumes S. lavernella, and caused 31.3% of fruitworm mortality in field surveys. Parasitoids included wasps (Hymenoptera) of the families Braconidae, Ichneumonidae, and Chalcididae. [ABSTRACT FROM AUTHOR]