The Plastic Larval Body Color of the Pale Grass Blue Butterfly Zizeeria maha (Lepidoptera: Lycaenidae) in Response to the Host Plant Color: The Maternal Effect on Crypsis

SIMPLE SUMMARY: The larvae of many butterflies and moths show various body colors within a species. We studied the possible effect of the host plant color on the plastic larval body color of the lycaenid butterfly Zizeeria maha, which shows various larval body colors ranging from green to red, even within a sibling group. The females laid eggs normally on both green and red leaves, despite showing a green preference. The larvae grew equally by consuming either green or red leaves. The number of red larvae decreased as the larvae grew, demonstrating a stage-dependent variation. When the larvae were fed either green or red leaves across multiple generations, the red larvae were significantly more abundant in the red leaf lineage than in the green leaf lineage. Moreover, the red-fed siblings showed a significantly higher red larval frequency than the green-fed siblings in the red leaf lineage but not in the green leaf lineage. These results suggest that, in this butterfly species, the plastic larval body color for crypsis may be affected not only by the color of the leaves that the larvae consume but also by the color of the leaves that their mothers consume, in addition to a stage-dependent color variation. ABSTRACT: Many lepidopteran larvae show body color polyphenism, and their colors may be cryptic on the host plant leaves. To elucidate the effect of the host plant color on the plastic larval body color, we focused on the lycaenid butterfly Zizeeria maha, which shows various larval body colors ranging from green to red, even within a sibling group. We showed that oviposition was normally performed on both green and red leaves, despite a green preference and the fact that the larvae grew equally by consuming either green or red leaves. The number of red larvae decreased from the second instar stage to the fourth instar stage, demonstrating a stage-dependent variation. When the larvae were fed either green or red leaves across multiple generations of the lineages, the red larvae were significantly more abundant in the red leaf lineage than in the green leaf lineage. Moreover, the red-fed siblings showed a significantly higher red larval frequency than the green-fed siblings in the red-leaf lineage but not in the green-leaf lineage. These results suggest that, in this butterfly species, the plastic larval body color for crypsis may be affected not only by the color of the leaves that the larvae consume (single-generation effect) but also by the color of the leaves that their mothers consume (maternal effect), in addition to a stage-dependent color variation.