Search

The cabbage armyworm, Mamestra brassicae, has winter-and aestival- diapause pupae (WD- and AD-pupae) showing differences in the strength of diapause. We tried to quantify diapause-strength by measuring the doses of 20-hydroxyecdysone (20-E) required to induce adult development in WD-, AD- and decerebrated non-diapause pupae (ND-pupae). The role of the brain in the regulation of diapause-strength was studied through the decerebration and brain-reimplantation of WD-and AD-pupae. The 20-E doses required for adult development were small within the first 2 days of pupation, and increased thereafter to reach a constant level about 10 days after pupation in AD- and decerebrated ND-pupae. The required 20-E doses in WD-pupae increased for more than 40 days after pupation. When 0-day-old WD- and 0-day-old AD-pupae were decerebrated, required 20-E doses increased after pupation and reached a constant about 10 days later. The required 20-E dose reached a constant level in decerebrated WD-pupae that was smaller than that observed for decerebrated ND- and WD-pupae. Furthermore, the required doses increased when 0-day-old WD-pupal brains were reimplanted into decerebrated WD- and decerebrated ND-pupae. In WD-, AD- and decerebrated ND-pupae, diapause-strength can be represented as the 20-E dose required for adult development. Diapause-strength is weak after pupation, increases thereafter, and reaches a constant about 10 days later in AD- and decerebrated ND-pupae. In WD-pupae, diapause-strength increases for more than 40 days after pupation and reaches a level that is twice that estimated for AD-pupae. Brains of diapausing WD-pupae may secrete a factor that suppresses the 20-E responsiveness of pupal organs, for the purpose of maintaining winter-diapause.

Diapause pupae of Papilio xuthus show color polymorphism, represented by diapause-green, orange, and brownish-orange types that are each associated with specific pupation sites. We investigated the role of the site of pupation on the induction of the development of orange types (or brownish-orange types), and the endocrine mechanism underlying the control of color polymorphism in short-day pupae. All short-day larvae of the wandering stage developed into orange or brownish-orange type pupae when they were placed in rough-surfaced containers after gut-purge. Utilizing a pharate pupal ligation between the thorax and abdomen, the endocrine mechanism underlying the control of color polymorphism was shown to involve a head-thorax factor (Orange-Pupa-Inducing Factor: OPIF) that induced orange types in short-day pupae. OPIF was bioassayed using the ligated abdomens of short-day pharate pupae. OPIF was extractable with 2% NaCl solution from 5th-instar larval ganglia complexes following the mesothoracic complex (TG(2,3)-AG(1-7)), but it could not be extracted with either acetone or 80% ethanol solution. OPIF may not exist in the brains of day-0 pupae or in brain-subesophageal ganglion and prothoracic ganglion complexes of 5th-instar larvae. The short-day pharate pupae responded to OPIF in a dose-dependent manner.

The small copper butterfly, Lycaena phlaeas daimio, has pupal beige/black polymorphism, the development of which is found to be controlled in an apparent association with the development of adult seasonal polymorphism (spring and summer morphs) by photoperiod and temperature in the larval stages. That is, the pupae of beige and black types developed under long-day and short-day conditions tend to develop into brown-winged and red-winged adults, respectively. In addition, a large proportion of long-day pharate pupae chilled at 4 degrees C for 5 days were observed to develop into pupae whose head-thoracic complexes and abdomens were judged to be of the black and intermediate types, respectively. They developed into adults with redder wings as compared to those obtained from unchilled pupae. The results indicate that the physiological mechanism underlying the photoperiodic control of the development of adult seasonal polymorphism may also play a significant role in the determination of pupal beige/black polymorphism in L. phlaeas daimio. Furthermore, cuticle melanization was found to be induced in the head-thoracic complexes of pupae by chilling of the pharate pupae. Melanization of pupal cuticle seems to occur in a close association with the development of reddish-winged adults.

The swallowtail butterfly, Papilio xuthus L., exhibits seasonal diphenism, i.e., spring and summer morphs, the development of which is determined by photoperiod and temperature imposed during the larval stage. Larvae reared under long day conditions at 25°C develop into summer morphs without pupal diapause, while larvae reared under short day conditions at 20°C develop into spring morphs after diapause development at 4°C for more than three months. To investigate the neuroendocrine mechanism regulating seasonal morph development, the activity of the summer-morph-producing hormone (SMPH) was tried to assayed by using male short day pupae of P. xuthus that accomplished diapause development at 4°C. The wing patterns of male butterflies shifted toward summer morphs when short day pupae were treated with the SMPH at an adequate stage. SMPH activity was detected in 2% NaCl extracts of the brain-subesophageal ganglion (Br-SG) complexes of P. xuthus long day pupae. Chilled male short day pupae responded ...

The pupae of Papilio xuthus show green, brown, and orange color polymorphism. The color of the pupal body is determined by a hormone that produces brown coloration, a hormone called pupal-cuticlemelanizing hormone (PCMH) which is secreted from brain-suboesophageal ganglion and prothoracic ganglion (Br-SG-PG) complexes during the pharate pupal stage. PCMH was extracted with 2% NaCl from Br-SG-PG complexes of P. xuthus green pupae. When pharate pupae producing brown pupae (brown-pupa-producers) were ligatured between the thorax and abdomen with cotton thread, the head-thorax complex developed into the brown type and the abdomens into the green type. Ligatured abdomens treated with crude PCMH produced intermediates of green- and brown-pupae (melanization degree of grades 0–3), which was used to assay PCMH-activity. Extracts of Br-SG complexes from Bombyx mori adults also shifted the color of the pupal cuticle toward the brown type in ligatured P. xuthus abdomens of brown-pupa-producers. The molecula...

The cabbage armyworm, Mamestra brassicae, enters winter and aestival diapause in the pupal stage under 10L-14D and 16L-8D, respectively, at 23°C. It develops without pupal dormancy under 14L-10D at 23°C. In 6th-instar larvae, the hemolymph ecdysteroid titers as well as the activity and sensitivity of the prothoracic glands (PGs) were nearly the same in the diapause- and nondiapause-programmed larvae. In non-diapause pupae (ND-pupae), the ecdysteroid titer peaked in the first half of the pupal stage. By contrast, in winter and aestival diapause pupae (WD- and AD-pupae), the ecdysteroid titer remained low after pupation. The ecdysteroid titer in diapausing AD-pupae was 8- to 10-times higher than that in diapausing WD-pupae. PGs from 5th-instar and 6th-instar larvae, as well as those from pupae, secreted ecdysteroids and showed a far stronger response to big prothoracicotropic hormone (PTTH) than to small PTTH in vitro. PG activity and its sensitivity to big PTTH fluctuated in a stage-dependent mann...

To investigate whether four Papilio species, Papilio xuthus, P. machaon, P. bianor and P. helenus, have two molecular forms of the prothoracicotropic hormones (PTTHs), referred to as big- and small-PTTHs, the PTTHs were extracted and fractionated from their pupal brains. The activating ability of big- and small-PTTH fractions was examined by the in vitro assay using the prothoracic glands (PGs) of 2-day-old 5th-instar larvae of their own and several other papilionid species. Big- and small-PTTH fractions activated the larval PGs of their own species to increase the ecdysteroid secretion in vitro. The doses of small-PTTH fractions for activating the larval PGs were 8- to 10-times larger than those of big-PTTH fractions. The big- and small-PTTH fractions as well as those of P. machaon activated the PGs of 2-day-old 5thinstar larvae of several heterogeneous papilionids, but the activating ability did not always decrease with the distance of the genetic (or phylogenetic) relationships. The results in...