Oviposition Preference and Nutritional Indices of Papilio polytes L. (Papilionidae) Larvae on Four Rutaceous (Sapindales: Rutaceae) Host Plants

Oviposition preference and larval developmental performance of the butterfly, Papilio polytes L. on four rutaceous host plants, Citrus aurantifolia (Chrism.) Swing, Citrus reticulata Blanco, Citrus hystrix DC, and Murraya koenigii (L.) Sprengle, were investigated in outdoor cages. Maxima of eggs were laid on C. reticulata, followed by C. aurantifolia, but the numbers laid on the two host plants were not significantly different from each other; however, these numbers differed significantly (F = 155.70; P < 0.01) from those laid on C. hysrix and M. koenigii; the last host plant was the least preferred for egg laying. Leaves were significantly the preferred site (and in turn the underside of leaves) over stems for deposition of eggs in all host plants; negligible number of eggs was also laid on plant pots. The duration of 5th instar larval development was the shortest on C. reticulata and significantly different (P < 0.01) from that on M. koenigii, but did not differ significantly between the three Citrus species. The nitrogen content in leaves of all four host plants differed significantly (P < 0.01), with C. reticulata containing 4.52%, followed by C. aurantifolia (4.37%), C. hystrix (4.29%), and M. koenigii (3.73%), while the water content of leaves was significantly the lowest in M. koenigii (71.72%), compared to the three Citrus species (76.38–79.12%) among which the water content did not significantly differ. Relative consumption rate (RCR) and fecal dry weight of 5th instar larvae feeding on M. koenigii were the highest and significantly different (P < 0.01) from the other three host plants. Pupal dry weight, relative growth rate (RGR), efficiency conversion of digested food (ECD), efficiency conversion of ingested food (ECI) of M. koenigii were significantly lowest compared to the three Citrus species. The values of RGR, ECD, and ECI of the 5th instar larvae were similar for the three Citrus species; the approximate digestibility (AD) values were similar for all four host plants. This study shows that C. reticulata was the best host plant among the three Citrus spp. and M. koenigii was the least preferred.