Delia antiqua is categorized as a specialist herbivore, with oviposition and larval feeding occurring only on plants in the genus allium. However, ovipositional "errors" have long been observed. Assays of egg deposition on a range of artificial resources demonstrate oviposition on poor resources, even in the presence of the best resource. This trend is consistent across years, generations of flies, fly populations, and graduate student assayists. This trend is not explainable by either the behavioral chain or the rolling fulcrum oviposition models and was key in the development of the jittery neural math model. Deterrents (chemical and visual, singly and in combination) were added to the artificial resource array and presented to gravid onion flies. The resulting patterns of egg deposition were compared to those predicted by the jittery neural math model. The jittery neural math model predicts that the slope of the line describing distribution of eggs will not change in the presence of deterrents, but that the intercept (or amplitude) of the line describing the ovipositional response will decrease with increasing levels of deterrency. This model predicts that the ovipositional response is suppressed by deterrents, but not stopped. Outcomes of tests with various chemical deterrents, including trans-cinnamaldehyde and phenethyl alcohol were fully consistent with the predictions of the jittery neural math model.
Species 1: Diptera Anthomyiidae Delia antiqua (onion fly)
Keywords: oviposition behavior, model testing
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