Regulatory mechanisms in phenotypic plasticity of diapause and nondiapause pupal colouration of the swallowtail butterfly Papilio machaon

Nondiapause pupae of Papilio machaon L. exhibit pupal colour diphenism comprising green–yellow and brown–white types. To understand the regulatory mechanism underlying the control of pupal colouration in P. machaon, the effect of environmental cues on diapause and nondiapause pupal colouration is investigated. When larvae reared under short‐day and long‐day conditions are allowed to pupate in sites with a smooth surface and a yellow background colour, all diapause pupae exhibit a brown–white type and 89.5% of nondiapause pupae exhibit a green–yellow type, respectively. With rough‐surface pupation sites, all diapause pupae exhibit brown–white and intermediate types, whereas a large proportion of nondiapause pupae exhibit brown–white and intermediate types, although some exhibit a green–yellow type. When extracts prepared from the head‐thoracic and thoracic‐abdominal regions of larval central nervous systems are injected into the ligated abdomens of P. machaon short‐day pharate pupae, all recipients exhibit a brown–white colouration. Furthermore, when each extract is injected into the ligated abdomen of Papilio xuthus L. short‐day pharate pupae with orange‐pupa‐inducing factor activity, recipients injected with the head‐thoracic extract exhibit the brown type, whereas those injected with the thoracic‐abdominal extract exhibit an orange colour. The results indicate that the response to the environmental cues of pupation site in P. machaon changes according to the photoperiodic conditions experienced during larval stages, and that at least two hormonal factors producing brown–white pupae are located in the larval central nervous system, with the secretion of these factors being regulated by the recognition of environmental cues in long‐day larvae.     

The effect of larval photoperiod on pupal colour and diapause in swallowtail butterflies

ABSTRACT.

• 1 There are significant differences in the effects of larval photo-period on diapause and pupal colour among the species Papilio polyxenes Fabr., P.troilus L., Battus philenor (L.) and Eurytides marcellus (Cramer).
• 2 Diapause and pupal colour in P.polyxenes and P.troilus are strongly influenced by larval photoperiod, short photophase eliciting brown diapausing pupae. Photoperiods of 15L:9D permit the expression of the green and brown pupal colour alternatives.
• 3 Pupal colour in B.philenor and E.marcellus is not affected by larval photoperiod, but short photophase induces diapause in these species.
• 4 All species except B.philenor show an association between brown pupal colour and diapause: Emarcellus when reared on long (midsummer) photophase, P.polyxenes and P.troilus when reared on short (autumnal) photophase.
• 5 In P.polyxenes, short photophase can affect pupal colour responses directly, whether the individual enters diapause or not.
• 6 Differences among the species are related to differences in the ecology of their natural pupation sites.

     

The evolution of environmentally-cued pupal colour in swallowtail butterflies: natural selection for pupation site and pupal colour

1. Environmentally-cued pupal colour in swallowtail butterflies has been hypothesized to evolve as a consequence of (a) the evolution of a preference for pupation sites above the ground that vary in colour and (b) natural selection for crypsis on such sites.
2. This hypothesis was tested by comparing the field survival of green and brown Papilio polyxenes Fabr. pupae placed on green or brown pupation sites that were either above the ground on near the ground.
3. Green pupae on green sites above the ground had a significantly higher probability of survival than did all other pupal colour and pupation site combinations.
4. Pupae on sites above the ground were more likely to be preyed upon during the day, whereas those on sites near the ground were more likely to be preyed upon during the night, suggesting that variation in nocturnal and diurnal predation influences the evolution of pupation site preference.
5. To the extent that diurnal predators use colour vision to locate prey, diurnal predation should favour environmentally-cued pupal colour.     

Convergent evolution of neuroendocrine control of phenotypic plasticity in pupal colour in butterflies

Phenotypic plasticity in pupal colour occurs in three families of butterflies (the Nymphalidae, Papilionidae and Pieridae), typically in species whose pupation sites vary unpredictably in colour. In all species studied to date, larvae ready for pupation respond to environmental cues associated with the colour of their pupation sites and moult into cryptic light (yellow–green) or dark (brown–black) pupae. In nymphalids and pierids, pupal colour is controlled by a neuroendocrine factor, pupal melanization-reducing factor (PMRF), the release of which inhibits the melanization of the pupal cuticle resulting in light pupae. In contrast, the neuroendocrine factor controlling pupal colour in papilionid butterflies results in the production of brown pupae. PMRF was extracted from the ventral nerve chains of the peacock butterfly Inachis io (Nymphalidae) and black swallowtail butterfly Papilio polyxenes (Papilionidae). When injected into pre-pupae, the extracts resulted in yellow pupae in I. io but brown pupae in P. polyxenes. These results suggest that the same neuroendocrine factor controls the plasticity in pupal colour, but that plasticity in pupal colour in these species has evolved independently (convergently).     

Pupal colour dimorphism in a desert swallowtail (Lepidoptera: Papilionidae) is driven by changes in food availability,not photoperiod

1. The swallowtail butterfly Battus polydamas archidamas Boisduval, 1936, exhibits polyphenism for pupal coloration (green and brown). It is distributed across arid regions with winter rains and is monophagous on Aristolochia plants, which emerge after the winter rains and dry out the during summer. Thus, day length does not covary positively with host plant productivity. It was hypothesised that pupal colour was driven by food availability, not photoperiod. The benefits of pupal coloration matching the colour of pupation sites in terms of field survival were also investigated to evaluate the adaptive value of pupa colour. 2. Larvae were reared under a factorial array of two photoperiods (LD 10:14 h and LD 14:10 h) and two food availability regimes (leaves ad libitum and available every other day) to assess the frequency of green and brown pupae. Field survival of green and brown pupae was quantified in three commonly used habitats that differ in background coloration (cacti, rocks and shrubs). 3. Food availability determined pupal colour. Larvae in the ad libitum regime resulted mostly in green pupae, while those with restricted food were mostly brown. In contrast, photoperiod did not influence pupal colour. Survival probability of pupae placed on cacti was higher than those placed on rocks and shrubs, and the lowest predation risk across habitats was for green pupae on cacti. 4. Food availability plays a major role in the seasonal polyphenism for pupal colour of specialist butterflies inhabiting arid environments with winter rains.     

Environmental control of pupal colour in swallowtail butterflies (Lepidoptera: Papilioninae): Battus philenor (L.) and Papilio polyxenes Fabr.

Abstract. 1. Some swallowtail butterflies produce both green and brown pupae. The phenotypes result from the joint action of genotype and environment and usually make the pupae cryptic in their habitats.
2. The major environmental cues influencing pupal colour in two swallowtail species were determined to be textural and optical.
3. Differences in the usage of these kinds of cues in the two species are thought to have evolved because of major differences in the pupation habitats. P.polyxenes , which usually pupates on slender stems amidst vegetation, responds more strongly to optical cues. B.philenor , which usually pupates on exposed surfaces of tree trunks and cliffs, responds more strongly to textural cues.
4. Differences in the overall tendency to produce brown pupae ('sensitivity': Hazel, 1977) are thought to be related to the frequency of brown pupation sites utilized by these two species: high average sensitivity in philenor , which often uses brown sites, and lower average sensitivity in polyxenes , which often uses green sites.     

Pupation site preference and environmentally cued pupal colour dimorphism in the swallowtail butterfly Papilio polyxenes Fabr. (Lepidoptera: Papilionidae)

Environmentally cued polymorphisms are hypothesized to evolve when the environment is coarsegrained and different genotypes are unable to choose the habitats in which they are most fit. In Papilio polyxenes , which has an environmentally cued pupal colour dimorphism, there is genetic variation in both tendency to produce brown or green pupae and preference for green- or brown-inducing pupation sites, but the two traits are not correlated.     

Effect of habitat type and soil moisture on pupal stage of a Mediterranean forest pest (Thaumetopoea pityocampa)

相似文献   

Diapause pupal color diphenism induced by temperature and humidity conditions in Byasa alcinous (Lepidoptera: Papilionidae)

We investigated whether diapause pupae of Byasa alcinous exhibit pupal color diphenism (or polyphenism) similar to the diapause pupal color polyphenism shown by Papilio xuthus. All diapause pupae of B. alcinous observed in the field during winter showed pupal coloration of a dark-brown type. When larvae were reared and allowed to reach pupation under short-day conditions at 18 °C under a 60 ± 5% relative humidity, diapause pupae exhibited pupal color types of brown (33%), light-brown (25%), yellowish-brown (21%), diapause light-yellow (14%) and diapause yellow (7%). When mature larvae reared at 18 °C were transferred and allowed to reach pupation at 10 °C and 25 °C under a 60 ± 5% relative humidity after a gut purge, the developmental ratio of brown and light-brown, yellowish-brown, and diapause light-yellow and diapause yellow types was 91.2, 8.8 and 0.0% at 10 °C, and 12.2, 48.8 and 39.0% at 25 °C, respectively. On the other hand, when mature larvae reared at 18 °C were transferred and allowed to reach pupation at 10 °C, 18 °C and 25 °C under an over 90% relative humidity after a gut purge, the developmental ratio of brown and light-brown, yellowish-brown, and diapause light-yellow and diapause yellow types was 79.8, 16.9 and 3.3% at 10 °C, 14.5, 26.9 and 58.6% at 18 °C, and 8.3, 21.2 and 70.5% at 25 °C, respectively. These results indicate that diapause pupae of brown types are induced by lower temperature and humidity conditions, whereas yellow types are induced by higher temperature and humidity conditions. The findings of this study show that diapause pupae of B. alcinous exhibit pupal color diphenism comprising brown and diapause yellow types, and suggest that temperature and humidity experienced after a gut purge are the main factors that affect the diapause pupal coloration of B. alcinous as environmental cues.     

Pupal colour polymorphism in Papilio machaon L. and the survival in the field of cryptic versus non-cryptic pupae

• 1 A field experiment was carried out in a natural habitat of Papilio machaon L. in southern Sweden to assess the evolutionary significance of pupal colour polymorphism.
• 2 Cryptic and non-cryptic pupae were planted in pairs in the vegetation, and exposed to predators.
• 3 The protective coloration conferred a selective advantage approximating 1.5 on the cryptic pupae of the summer generation. In the overwintering generation no difference could be detected between the predation of cryptic and non-cryptic pupae.
• 4 The adaptive fitness of protective coloration, as determined by the different rates of elimination of the colour morphs, was greater for the green pupae than for the brown ones.
• 5 Natural selection favours the evolution of a seasonal difference in the proportion of green and brown pupae in the summer and hibernating generations of P.machaon.

     

Interactions of environmental factors influencing pupal coloration in swallowtail butterfly Papilio xuthus

The swallowtail butterfly Papilio xuthus Linné [Lepidoptera: Papilionidae] exhibits pupal protective color polyphenism. Interactions of various environmental factors on pupal coloration were analyzed in non-diapausing individuals. Under sufficient light (200lux), most pupating larvae became green pupae when the surface of the pupation site was smooth, while they became brown when the surface was rough. Tactile signals are the positive environmental factors causing induction of the brown pupal coloration. In dark boxes, the induction of the brown pupal coloration was easily induced even on a smooth surface, suggesting that light suppresses induction of brown coloration. Different colors of pupation sites did not affect pupal coloration under sufficient light. Environmental factors received during a critical period both before girdling and after girdling affected pupal coloration. When tactile signals received from rough surfaces reach threshold levels during pupation, brown pupal coloration is determined. Larvae reared under a daily periodicity of natural light formed a girdle at midnight, subsequently, the prepupae received strong daylight the following day. Under natural light most larvae produced brown pupae on rough surfaces and green pupae on smooth surfaces.     

Natural pupation sites of swallowtail butterflies (Lepidoptera: Papilioninae): Papilio polyxenes Fabr., P.glaucus L. and Battus philenor (L.)

Abstract. 1. Natural pupation sites have been found in Papilio polyxenes and P.glaucus by releasing prepupal larvae marked with UV-fluorescent paint and locating them at night with a UV lamp, and in Battus philenor by searching a forest habitat where the larval foodplant is abundant.
2. P.polyxenes , a species of weedy habitats, pupates off the ground on a variety of substrates including grasses, weed stalks, posts, etc. The pupae may be green or brown, resembling the substrate.
3. P.glaucus , a species of forest habitats, pupates very close to the ground in the litter and has monomorphic brown pupae.
4. B.philenor , also a forest species, pupates on exposed surfaces (chiefly tree-trunks or cliffs) well off the ground. Its pupae may be brown or green, but the latter were found only on the slenderest twigs.
5. The results for polyxenes and glaucus support the generalization of Clarke & Sheppard (1972) that species of stable habitats are likely to have monomorphic pupae, while those of habitats in which available sites may not be so similar from one generation to the next will be dimorphic.
6. B.philenor is more problematical, but its tendency towards pupal monomorphism (brown) is logical in relation to its common pupation sites.     

Pupal polymorphism in the butterfly Danaus chrysippus (L.): environmental, seasonal and genetic influences

The pupae of the tropical butterfly Danaus chrysippus are either green or pink the switch being operated by a ‘greening’ hormone produced in the larval head. Both environmental and genetic cues are involved in controlling the endocrine mechanism. The environmental factors identified are of two distinct kinds: proximate factors influence pupal colour after the larva has selected its pupation site, whereas ultimate factors are effective at an earlier stage, either prompting choice of pupation site by the larva or priming pupation physiology in a particular direction. Genetic factors preadapt the larva to form a pupa which will be cryptic in the normal or average conditions, climatic or biogeographical, anticipated in its environment. The proximate factors demonstrated are background colour, darkness, light quality (wavelength) and humidity. There is some evidence that substrate texture may also be relevant. Ultimate factors are temperature, humidity and species of larval foodplant. Two closely linked gene loci which govern the phenotype of adult morphs and races either have a pleiotropic effect on pupa colour or are closely linked with other genes which do so. Moreover, the two loci interact epistatically with respect to their pupation effects. Factors producing predominantly green pupae are plant substrates, yellow background, darkness, yellow light, high humidity, high temperature, the b allele at the B locus when homozygous and, on non-plant substrates, the C allele at the C locus. High frequencies of pink pupae result on non-plant substrates, red backgrounds, in blue light, low humidity, low temperatures and in B- and cc genotypes. The C locus alleles, C and c, interact epistatically with the B alleles, their effect on choice of pupation site being determined by linkage phase. Of the two foodplants tested, Calotropis produced a high frequency of green pupae and Tylophora of pinks. The seasonal cycling of rainfall, temperature, availability or condition of foodplant, and gene frequencies are all correlated with oscillations in the frequencies of green and pink pupae. Though genotype influences pupa colour, all genotypes are capable of forming pupae of both colours. The variation can therefore be attributed to an environmental polyphenism superimposed upon a genetic polymorphism. The hormone producing green pupae emanates from the head during the prepupal period. Denied hormonal influence, the pupa is pink. Pupal colour is judged to be aposematic at close range and cryptic at distance.     

Diapause, migration and pyrethroid-resistance dynamics in the cotton bollworm, HeIicoverpa armigera (Lepidoptera: Noctuidae)

Abstract.

• 1 A diapause induction and duration experiment was conducted in the laboratory on Indian Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) where 79% of individuals had extended pupal periods. At 22°C and 26°C respectively, 57% and 100% of the pupae had emerged 145 days after pupation.
• 2 A mathematical model was developed to investigate the interactions between diapause, migration and pyrethroid resistance frequency development in both eastern Australia and Andhra Pradesh, India.
• 3 The effect of diapause was different in the Australian and Indian cases, providing a mechanism to conserve resistance and susceptibility respectively.
• 4 For Australia, the model simulated discriminating dose data reasonably well and showed that resistance frequencies could rise prior to the pyrethroid window without invoking cross-resistance to non-pyrethroid insecticides applied to cotton.
• 5 The saw-toothed seasonal cycle of resistance development could be simulated in the Indian case without hypothesizing the existence of susceptible migrants.
• 6 The implications of‘refugia’populations for H.armigera insecticide resistance management programmes are discussed.

     

Two different sensory mechanisms for the control of pupal protective coloration in butterflies

The butterflies Graphium sarpedon nipponum Fruhstorfer and Papilio xuthus Linné show pupal protective color polymorphism, but the two species appear to have different sensory mechanisms for determining pupal coloration. When light was of sufficient illumination, the larvae of Graphium sarpedon became bright yellowish green pupae on white pupation boards and reddish brown pupae on black pupation boards. The pupal coloration thus strongly depended on the brightness of the pupation site. In addition, larvae became bright yellowish green pupae in complete darkness. From these results, measurement of the illumination suggested that pupal color is determined by the illuminant difference between incidence light from the dorsal direction and ventral light from a paper board; i.e., the sum of the reflected light of the board plus the penetrated light passing through the board. The illuminant difference required for reddish brown coloration was 40 lux or more. The optical signals received through the stemmata during a critical period before formation of the thorax garter (band string) were important for coloration. By contrast, in Papilio xuthus, successive tactile signals from a rough surfaced pupation site during a critical period before and after formation of the garter were important for determining brown pupal coloration.     

Prothoracicotropic Hormone Acts as a Neuroendocrine Switch between Pupal Diapause and Adult Development

Diapause is a programmed developmental arrest that has evolved in a wide variety of organisms and allows them survive unfavorable seasons. This developmental state is particularly common in insects. Based on circumstantial evidence, pupal diapause has been hypothesized to result from a cessation of prothoracicotropic hormone (PTTH) secretion from the brain. Here, we provide direct evidence for this classical hypothesis by determining both the PTTH titer in the hemolymph and the PTTH content in the brain of diapause pupae in the cabbage army moth Mamestra brassicae. For this purpose, we cloned the PTTH gene, produced PTTH-specific antibodies, and developed a highly sensitive immunoassay for PTTH. While the hemolymph PTTH titer in non-diapause pupae was maintained at high levels after pupation, the titer in diapause pupae dropped to an undetectable level. In contrast, the PTTH content of the post-pupation brain was higher in diapause animals than in non-diapause animals. These results clearly demonstrate that diapause pupae have sufficient PTTH in their brain, but they do not release it into the hemolymph. Injecting PTTH into diapause pupae immediately after pupation induced adult development, showing that a lack of PTTH is a necessary and sufficient condition for inducing pupal diapause. Most interestingly, in diapause-destined larvae, lower hemolymph titers of PTTH and reduced PTTH gene expression were observed for 4 and 2 days, respectively, prior to pupation. This discovery demonstrates that the diapause program is already manifested in the PTTH neurons as early as the mid final instar stage.     

Dispersal and prepupation behavior of Chilean sympatric Drosophila species that breed in the same site in nature

We investigated dispersal patterns of Drosophila larvae searchingfor pupation sites over three substrates to determine the roleof spatial heterogeneity and presence of other species on prepupationbehavior. We used D. melanogaster, D. hydei, and D. pavani whoseparents emerged from apples collected in one orchard. Each speciesshowed different preferences for substrates on which to pupate,particularly in the presence of another Drosophila species.Larval locomotion rate and turning behavior in D. melanogaster,D. hydei, and D. pavani were modified depending this upon thetype of substrate (agar and sand) on which the larvae crawled.These two behaviors are involved in dispersal and aggregationof pupae. Distance between pupae of the same species decreaseswhen larvae of another species pupate on the same substrate.Aggregated distributions over the substrates lead to patcheswith few or no individuals. These could serve as pupation sitesfor other Drosophila species that, in nature, also emerge fromsmall breeding sites.     

Closely related parasitoids induce different pupation and foraging responses in Drosophila larvae

Few examples exist where parasites manipulate host behaviour not to increase their transmission rate, but their own survival. Here we investigate fitness effects of parasitism by Asobara species in relation to the pupation behaviour of the host, Drosophila melanogaster . We found that Asobara citri parasitized larvae pupate higher in rearing jars compared to unparasitized controls, while A. tabida pupated on or near the medium. No change in pupation site was found for three other species. A follow-up experiment showed a non-random distribution of parasitized and unparasitized pupae over the different jar parts. To test the adaptiveness of these findings, we performed pupal transfer experiments. Optimum pupation sites were found to be different between host individuals; wall individuals survived better than bottom individuals, but bottom individuals did worse at the wall. Two parasitoid species that alter pupation site significantly showed high rates of diapause at their 'preferred' pupation site. For one of them, A. citri , pupation occurred at the optimal site for highest survival (emergence plus diapause). From literature we know that pupation height and foraging activity are genetically positively linked. Therefore, we implement a short assay for rover/sitter behavioural expression by measuring distance travelled during foraging after parasitism. For one out of three species, foraging activity was reduced, suggesting that this species suppresses gene expression in the for pathway and thereby reduces pupation height. The parasitoid species used here, naturally inhabit widely different environments and our results are partly consistent with a role for ecology in shaping the direction of parasite-induced changes to host pupation behaviour. More parasitoids are found on the wall of the rearing jar when they originate from dry climates, while parasitoids from wet climates pupate on the humid bottom.     

葱蝇非滞育、 冬滞育和夏滞育蛹发育和形态特征比较

昆虫非滞育、 冬滞育和夏滞育蛹具有不同的生理和发育过程。本研究以葱蝇Delia antiqua作为模式种, 以黑腹果蝇Drosophila melanogaster蛹的发育形态特征和命名为参照, 用解剖、 拍照、 长度测量和图像处理等方法系统地比较研究了非滞育、 冬滞育和夏滞育蛹的发育历期和形态变化, 重点在头外翻和滞育相关发育和形态特征, 目的在于弄清非滞育、 冬滞育和夏滞育蛹发育和形态特征差异, 为滞育发育阶段的识别、 滞育分子机理研究奠定形态学基础。冬滞育蛹的滞育前期、 滞育期和滞育后期分别为4, 85和27 d, 夏滞育蛹的滞育前期、 滞育期和滞育后期分别为2, 8和22 d。从化蛹至头外翻完成为滞育前期, 头外翻完成约10 h内复眼中央游离脂肪体可见。头外翻的完成是滞育发生的前提, 非滞育、 夏滞育和冬滞育蛹头外翻发生在化蛹后的48, 36和83 h, 在头外翻过程中发育形态没有差异。头外翻的过程为： 首先, 头囊和胸部附肢从胸腔外翻, 头部形态出现; 然后, 腹部肌肉继续收缩, 将血淋巴和脂肪体推进头部及胸部附肢。葱蝇蛹在完成蛹期有效积温约15%时进入冬滞育或夏滞育。在滞育期, 蛹的形态一直停留在复眼中央游离脂肪体可见这一形态时期, 且冬滞育和夏滞育的蛹在形态上没有区别。在体长、 体宽和体重上, 冬滞育蛹最大, 夏滞育蛹次之, 非滞育蛹最小。在滞育后期, 在黄色体出现期间, 非滞育蛹的马氏管清楚可见, 呈绿色, 而滞育蛹的马氏管几乎不可见。本研究为认知昆虫滞育生理、 从发育历期和形态上推断滞育发育进程提供了依据。     

The effects of temperature on development of the large narcissus fly (Merodon equestris)

Eggs, larvae, pupae and adults of the large narcissus fly (Merodon equestris) were reared at a series of constant temperatures between 9–24°C. Egg development required from 37 days at 9°C to 7 days at 21.5°C. The low-temperature threshold for development was 6.7°C. Larvae reared at 1424°C were fully-grown after 18 weeks, but it took much longer for such insects to pupate, and adult flies emerged only after about 45 weeks of development. Large narcissus flies enter diapause during the larval stage and overwinter as fully-fed larvae, forming pupae in the following spring. Post-winter pupation and pupal development took from 169 days at 10°C to 36 days at 21.5°C. Of this, pupal development required from 91 days at 10°C to 19 days at 21.5°C. The low-temperature threshold for post-winter pupation and pupal development was 7.1°C, and for pupal development alone, 7.2°C. Females maintained at or below 19°C laid few eggs, whereas some females kept at or above 21.5°C laid more than 100 eggs (mean 69 ± 36). Approximately 50% of females maintained at or above 21.5°C laid less than 10 eggs during their lifetime. The mean egg-laying time was 6 to 9 days. Although temperatures at or below 19°C inhibited mating, once a female had mated, such temperatures did not prevent oviposition.