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

Abstract

AbstractThe mothSymmetrischema lavernella(Chambers) (Lepidoptera: Gelechiidae) has two feeding strategies on its host plantPhysalisLinnaeus (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 inPhysalis heterophyllaNees), consumes the developing ovules, and pupates in the fruit. InP.heterophylla, occupancy of the ovary byS. lavernellacauses 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 ofS. lavernellausing the fruitworm strategy was the frugivorous caterpillarHeliothis subflexa(Guenée) (Lepidoptera: Noctuidae), also a specialist ofPhysalis. The largerHeliothis subflexafeeds on the fruit externally, consumesS. lavernella, and caused 31.3% of fruitworm mortality in field surveys. Parasitoids included wasps (Hymenoptera) of the families Braconidae, Ichneumonidae, and Chalcididae.