Hardness and color of the oviposition substrate impact Anastrepha fraterculus female oviposition behavior

RUIZ, M. JOSEFINA; GOANE, L.; GABRIELA VALLADARES; PÁEZ-JEREZ, PAULA; SEGURA, DIEGO F; LOPEZ, LIZA; VERA, M. TERESA

Tapachula

Simposio; 10th International Symposium on Fruit lies of Economic Importance.; 2018

Background: Host selection in fruit flies is a crucial process for female fitness. Many species of fruit flies are polyphagous and exhibit a gradient of preference among different host species. Females use tactile, visual and olfactory cues during host finding and acceptance. Here we evaluated the effect of hardness and color of the oviposition substrate on female oviposition behavior of the highly polyphagous South American fruit fly, Anastrepha fraterculus. Methods: Mated females from a laboratory colony with no oviposition experience were used for the tests. Female oviposition preference was assessed in 1 L containers where 5 sexually mature females were offered two agar slices. Two dual choice experiments were run. In the first experiment, black agar slices that differed in hardness (four levels: H1 to H4 being H1 the softest and H4 the hardest) were offered in all possible combinations (H1 vs H2, H1 vs H3, and so on). In the second experiment, females were offered two agar slices from different colors (red, green, yellow and blue) and same hardness (H1); again in all possible dual combinations. Agar slices were removed after 48 h and the number of eggs laid scored. As control, no choice conditions were run for each hardness level and color.Results: Number of eggs laid under no choice conditions depended on oviposition substrate hardness. Females laid significantly more eggs in H2 substrates that the remaining hardness levels. This was confirmed under choice conditions. Females preferred the softer substrate in all cases which included the hardest substrate (H4 < H1, H2 or H3) and preferred the second hardness over the third (H2 > H3). The number of eggs laid in combinations H1 vs H2, and H1 vs H3 did not differ between options. Number of eggs laid under no choice conditions was independent of oviposition substrate color. Under dual choice conditions, the only combination that presented significant differences was the one involving yellow and blue slices, females preferred the yellow substrate. Cages with substrates of the same hardness or color (controls) exhibited no preference.Conclusions: Under the test conditions, the hardness of the substrate appeared to play a role in the oviposition preference. The behavior might be related to avoidance or reduction of ovipositor wear. The absence of a strong color preference could be related to the fact that color is mostly involved with host finding rather than host acceptance and therefore this cue is most relevant at long distances.