Presence of a cerebral factor showing summer‐morph‐producing hormone activity in the brain of the seasonal non‐polyphenic butterflies Vanessa cardui, V. indica and Nymphalis xanthomelas japonica (Lepidoptera: Nymphalidae)

Abstract

Presence of a cerebral factor showing summer-morphproducing hormone activity in the brain of the seasonal nonpolyphenic butterflies Vanessa cardui, V. indica and Nymphalis xanthomelas japonica (Lepidoptera: Nymphalidae) Abstract Three species of nymphalid butterflies, Vanessa cardui, V. indica and Nymphalis xanthomelas japonica, do not exhibit seasonal polyphenism in wing coloration. To determine whether seasonal non-polyphenic butterflies possess a cerebral factor affecting wing coloration, we used a Polygonia c-aureum female short-day pupal assay for detection of summer-morph-producing hormone (SMPH) activity in P. c-aureum. When 2% NaCl extracts of 25 brain-equivalents prepared from the pupal brains of V. cardui, V. indica or N. xanthomelas japonica were injected into Polygonia female short-day pupae, all recipients developed into summer-morph adults with dark-yellow wings, and the average grade score (AGS) of summer morphs showing SMPH activity was 3.8, 3.7 and 4.0, respectively. In contrast, when acetone or 80% ethanol extracts prepared from pupal brains were injected into Polygonia pupae, all recipients developed into autumn-morph adults with a dark-brown coloration and each exhibited an AGS of less than 0.5. Our results indicate that a cerebral factor showing SMPH activity is present in the pupal brain of seasonal non-polyphenic nymphalid butterflies, suggesting that a SMPH and cerebral factor showing SMPH activity occur widely among butterfly species. This finding will improve our understanding of the presence of cerebral factors showing interspecific actions of SHPH.

Changes of seasonal morph development induced by surgical operations in pupae of the large map butterfly Araschnia burejana Bermer (Lepidoptera: Nymphalidae)

“…Recently, a cerebral factor showing SMPH activity was detected in pupal brain‐extracts of the non‐polyphenic nymphalid butterflies V. cardui , V. indica and N . xanthomelas japonica using a Polygonia pupal assay, suggesting that a cerebral factor showing SMPH activity (or a SMPH) may be distributed widely in many species of butterflies (Tanaka et al, ). It is therefore necessary to investigate the detection of a cerebral factor showing SMPH‐activity in the pupal brain of A .…”

“…c‐aureum and P. xuthus , and SMPH activity is detectable using a Polygonia female SD‐pupal assay and a Papilio chilled‐male SD‐pupal assay (Endo et al, ; Ito et al, ). Recently, we also reported that a cerebral factor showing SMPH activity was detected in pupal brain‐extracts of Vanessa cardui , V. indica , and Nymphalis xanthomelas japonica , which do not exhibit seasonal polyphenism, using a Polygonia female SD‐pupal assay, although the roles of the cerebral factor showing SMPH activity have not been studied in these butterflies (Tanaka et al, ). Overall observations suggest that a cerebral factor showing SMPH activity is distributed in the pupal brains of many nymphalid butterflies.…”

Effect of larval brain extracts derived from three swallowtail butterflies, Papilio helenus L., P. machaon L. and P. memnon L., on seasonal morph development of P. xuthus L. (Lepidoptera: Papilionidae)

“…; Tanaka et al . ), we first detected this factor in the larval brains of four Papilio species in this work. These results revealed that a cerebral factor showing SMPH activity is already synthesized in the 5th larval stage, suggesting that this factor acts not only on the seasonal morph development in adults, but also on the unknown seasonal or phenotypic plasticity in larvae, if this factor is present in the young instar larval brains.…”

“…), and Vanessa cardui L., Vanessa indica Herbst and Nymphalis xanthomelas japonica Esper, which do not exhibit seasonal polyphenism (Tanaka et al . ) following a Polygonia female short‐day (SD) pupal assay to detect SMPH activity (Endo et al . ).…”

“…memnon confirmed our previous finding of a cerebral factor showing SMPH activity in the brain of three seasonally non‐polyphenic nymphalids (Tanaka et al . ), although it has been suggested that SMPH is a neuropeptide hormone in specific butterfly species showing seasonal diphenism involving wing coloration such as P. xuthus and Lycaena phlaeas daimio Seitz (Endo et al . ).…”