Molting Period Research Articles

TMEM39A and TMEM131 facilitate bulk transport of ECM proteins through large COPII vesicle formation

The growth of Caenorhabditis elegans involves multiple molting processes, during which old cuticles are shed, and new cuticles are rapidly formed. This process requires the regulated bulk secretion of cuticle components. The transmembrane protein-39 (TMEM-39) mutant exhibits distinct dumpy and ruptured phenotypes characterized by notably thin cuticles. TMEM-39 primarily co-localizes with the coat protein II complex (COPII) in large vesicles rather than small COPII vesicles. These TMEM-39-associated large vesicles (TMEM-39-LVs) form robustly during the molting period and co-localize with various extracellular matrix (ECM) components, including BLI-1 collagen, BLI-3 dual oxidase, and carboxypeptidases. Through immunoprecipitation using TMEM39A-FLAG and proteomics analysis in human sarcoma cells, we identify TMEM39A-associated proteins, including TMEM131. Knockdown of TMEM131 results in reduced TMEM39A-LV formation and collagen secretion in both C. elegans and human sarcoma cells, indicating a cooperative role between TMEM39A and TMEM131 in the secretion of extracellular components through the formation of large COPII vesicles. Given the conservation of TMEM39A and its associated proteins between C. elegans and humans, TMEM39A-LV may represent a fundamental machinery for rapid and extensive secretion across metazoans.

Utilization Ecdysterone Hormone of Krokot (Portulaca oleracea) Extract on Molting Activity in Mud Crabs (Scylla serrate)

The Scylla serrate mangrove crab is one of the leading fisheries commodities in terms of exports, only behind shrimp, tuna and shellfish. Crabs have a fairly high price in foreign markets and most of the mud crabs obtained from wild catches are soft shell crabs. In terms of price, cultivating soft shell crabs is quite profitable, but most cultivators have several problems such as long maintenance periods and inconsistent molting times so that they do not experience business continuity. Applying herbal extracts via injection is an effective method because all the substances that trigger molting directly enter the body. Physiological engineering is needed to speed up the molting phase and get the same molting time. This research aims to identify the ecdysterone content in purslane leaves and determine the optimum dose of purslane leaf extract which can encourage skin molting in mud crabs. This research used a Randomized Block Design (RBD). The in silicons test results show that the compound that has the smallest binding affinity is ecdysone, namely -6.80 kcal/mol. Based on analysis of variance, the best molting percentage occurred in treatment B at 55.50%. The fastest molting period occurred in treatment C, namely on days 4 to 29 after injection. Treatments B and C had the highest survival rate, namely 100%, while in terms of increasing body weight and carapace width, the effect of all treatments was not significantly different. The water quality results for all groups were still within the optimum value, temperature 26.40 – 33.80ºC; pH 6.83 – 7.20; salinity 20.70 – 26.70 ppt and dissolved oxygen 4 – 4.52 ppm

Enhancing laying performance and immunity via probiotic and vitamin additives during induced molting.

Molting is induced in commercial laying hens to rejuvenate the reproductive system and increase egg production. However, this process causes stress and reduces bird health and performance. The experiment was conducted to study the effect of multi probiotics and vitamin additives on induced molting in 240 ISA Brown hens. Hens were randomly divided into four groups receiving probiotic and vitamin additives (I-IV) during different period of molting. During the whole molting process, the laying performance indexes such as egg laying rate, egg quality, ovary weight and oviduct lengths were measured, and the spleen index, serum immunoglobulin, immune response of NDV and AIV vaccine were monitored. Molted hens resumed 50% egg production in just 37 days, with 1.62% mortality. Egg quality such as egg weight, yolk color, Haugh unit, eggshell strength and protein height were significantly improved. After the second production peak, the reproductive organs and immune organs returned to normal, and the immune antibody titer of NDV vaccine increased significantly. Molting with probiotic and vitamin additives improve the laying performance and egg quality, reduce mortality, significantly improve immune function and vaccine titer, and help to enhance disease resistance and maintain production performance of aged laying hens.

Corazonin Stimulates Ecdysteroid Synthesis during the Molting Process of the Swimming Crab, Portunus trituberculatus.

The neuropeptide corazonin (Crz) exerts diverse physiological effects in insects, yet its role in crustaceans remains elusive. The abundant expression of Crz receptor (CrzR) in the Y-organs of several crustaceans suggests a potential involvement of Crz in regulating ecdysteroid synthesis. In this study, we examined the effects of PtCrz on ecdysteroid synthesis during the molting period of Portunus trituberculatus through PtCrz treatments and PtCrzR silencing. Our results showed that PtCrz peptide stimulates ecdysteroid levels and the gene expression involved in ecdysteroidogenesis both in vitro and in vivo, whereas dsPtCrzR treatments had opposite effects on ecdysteroid levels and associated gene expression. Thus, our study suggests that PtCrz may modulate ecdysteroid synthesis via Y-organ-expressed PtCrzR. Furthermore, we also discovered the involvement of PtCrz/PtCrzR signaling in regulating PtETH expression. Notably, the inhibitory effect of dsPtCrzR on ecdysteroid synthesis or PtETH expression can be reversed by PtCrz treatment, suggesting the potential existence of multiple receptors for PtCrz. This study provides new insights into the function of crustacean Crz and, for the first time, elucidates the presence of a neuropeptide that can stimulate ecdysteroid synthesis in crustaceans.

The effect of different fresh feeds on the growth and molting period of mud crab (Scylla serrata) cultivated in a single room system

The effect of different fresh feeds on the growth and molting period of mud crab (Scylla serrata) cultivated in a single room system

Flightless Molt Period and Habitat Selection of White-Naped Cranes (Antigone vipio) Revealed by Satellite Tracking

Flightless Molt Period and Habitat Selection of White-Naped Cranes (Antigone vipio) Revealed by Satellite Tracking

Using telemetry data and the sea ice satellite record to identify vulnerabilities in critical moult habitat for emperor penguins in West Antarctica

AbstractWe tracked adult emperor penguins from Rothschild Island, west Antarctic Peninsula in 2015/2016 during a summer with extensive sea ice of long duration, contrasting with past years of reduced sea ice extent associated with the recent, rapid, warming trend across the region. We fitted ARGOS PTT devices to penguins of unknown breeding status. Of 33 penguins tracked, nine returned to the colony, presumably to provision offspring. Their foraging trips lasted 9.6 ± 3.7 days, with maximum distances of 75 ± 45 km from the colony within coastal waters. Also, 18 instruments transmitted until the initiation of the annual moult. Penguins travelled at ~ 2.3 km h−1 before slowing for moult. Post-moult, some devices continued to transmit, with speeds of ~ 0.8 km h−1, plausibly due to ice drift, which is rapid in this region. Penguins remained within the seasonal sea ice throughout, staying within 100 km of land, and generally within 5 to 10 km of features (open water, polynyas, leads, icebergs) that offered potential access to the ocean. Penguins were unlikely to have been constrained by the extensive sea ice habitat in 2015/2016. Similar habitats would also have been available in most years of the satellite record (since 1979); however, the moult locations in 2015/2016 would not have been available in many years, and penguins would have needed to find alternative moult locations during some years. Despite uncertainties, the moult period is a critical time for emperor penguins, particularly as sea ice declines, potentially affecting adult survival.

Effects of dietary L-tryptophan supplementation on agonistic behavior, feeding behavior, growth performance, and nutritional composition of the Chinese mitten crab (Eriocheir sinensis)

In the pond culture of Chinese mitten crabs (Eriocheir sinensis), high stocking densities usually increase the frequency of agonistic behavior, which can directly impact crab integrity, survival, and growth and result in economic losses. We hoped to reduce agonistic behavior by adding additives to feed. In this study, we first observed the agonistic behavior of E. sinensis in 5 molting periods (from first molting to puberty molting) during the adult grow-out stage. Then, we assessed the effects of L-TRP as a feed additive on the agonistic behavior of juvenile, precocious, subadult, and adult crabs. Finally, we performed 106 days of cage culture to assess the effects of L-TRP on feeding behavior, animal vitality, growth performance, and nutritional composition. The results showed that the intensity of agonistic behavior was significantly higher after puberty molting than in other molting periods during the adult grow-out stage. Moreover, L-TRP supplementation inhibited the agonistic behavior of juvenile, subadult, and adult crabs, but it did not affect the precocious crabs. During cage culture, L-TRP significantly improved crab vitality after 3 weeks but not after 6 and 9 weeks, but it reduced the ingestion rate after 9 weeks. Moreover, the L-TRP group showed a significant increase in the weight gain rate and specific growth rate after the fourth molting. After 106 days of culture, the content of proline and fatty acids in the muscle decreased significantly after L-TRP diet supplementation. Some long-chain polyunsaturated fatty acids also decreased significantly in the hepatopancreas. However, we must focus on the adverse effects of L-TRP on Pro and fatty acid composition. Further research is required on the balance between inhibition of agonistic behavior and effects of L-TRP on the nutritional quality of E. sinensis.

Effects of cage type and the light-dark cycle on the behavior of hens subjected to forced molting.

In this study, the effects of cage type and the light-dark cycle on the behavior of hens before, during, and after forced molting were determined. For this purpose, 73-week-old hens were placed in the two different cage types used in the experiment. The barley method was used to induce molting at 75 weeks of age. The molting period lasted 35 days in total. The frequencies of walking, feeding, comforting, and preening behaviors were affected by the forced molting period. The addition of enrichment materials to the cage did not cause any changes in hen behavior. The light-dark cycle was important for the frequency of all examined behaviors except fighting behavior. No interaction was found among forced molting period, cage type, and light-dark cycle regarding behaviors. It is thought that there is a decrease in welfare-related behaviors at the end of the laying period and this decrease does not increase with forced molting using barley; on the contrary, appropriate forced molting applied to hens during this period will increase welfare. It was observed that cage type did not cause a significant difference in hen behavior during the forced molting period.

Incidental pinnipeds at high latitudes of the Vestfold Hills, Prydz Bay, East Antarctica

AbstractSpecies distributions are predicted to change with future climate-associated ecosystem changes such that so-called ‘vagrant’ individuals may become established or re-establish in areas currently thought to be beyond their principle ranges. Survey data were collated for occurrences of pinniped (seal) species at very high latitudes of the Vestfold Hills, East Antarctica. Aside from Weddell seals (Leptonychotes weddellii) and southern elephant seals (Mirounga leonina), which aggregate annually at the Vestfold Hills to breed and/or moult, three other pinniped species were observed with the recession of the fast-ice edge. Leopard seal (Hydrurga leptonyx) occurrences increased with an increase in a seasonally abundant prey resource, and crabeater seals (Lobodon carcinophaga) were seen at a time that coincides with their moult period. Occurrences of sub-adult male Antarctic fur seals (Arctocephalus gazella) increase the known southward range for this species and may reflect population increases at source populations in the Kerguelen Plateau area. Although there were no direct sightings of Ross seals (Ommatophoca rossii), their presence close to the Vestfold Hills was detected by underwater passive acoustic monitoring. Sightings of obligate drift-ice species and sub-Antarctic fur seals may change at the Vestfold Hills with climate-mediated changes in sea-ice conditions.

Functional importance of groups I and II chitinases, CHT5 and CHT10, in turnover of chitinous cuticle during embryo hatching and post-embryonic molting in the red flour beetle, Tribolium castaneum

Chitinases (CHT) comprise a large gene family in insects and have been classified into at least eleven subgroups. Many studies involving RNA interference (RNAi) have demonstrated that depletion of group I (CHT5s) and group II (CHT10s) CHT transcripts causes lethal molting arrest in several insect species including the red flour beetle, Tribolium castaneum, presumably due to failure of degradation of chitin in their old cuticle. In this study we investigated the functions of CHT5 and CHT10 in turnover of chitinous cuticle in T. castaneum during embryonic and post-embryonic molting stages. RNAi and transmission electron microscopic (TEM) analyses indicate that CHT10 is required for cuticular chitin degradation at each molting period analyzed, while CHT5 is essential for pupal-adult molting only. We further analyzed the functions of these genes during embryogenesis in T. castaneum. Real-time qPCR analysis revealed that peak expression of CHT10 occurred prior to that of CHT5 during embryonic development as has been observed at post-embryonic molting periods in several other insect species. With immunogold-labeling TEM analysis using a fluorescein isothiocyanate-conjugated chitin-binding domain protein (FITC-CBD) probe, chitin was detected in the serosal cuticle but not in any other regions of the eggshell including the chorion and vitelline membrane layers. Injection of double-stranded RNA (dsRNA) for CHT5 (dsCHT5), CHT10 (dsCHT10) or their co-injection (dsCHT5/10) into mature adult females had no effect on their fecundity and the resulting embryos developed normally inside the egg. There were no obvious differences in the morphology of the outer chorion, inner chorion and vitelline membrane among eggs from these dsRNA-treated females. However, unlike dsCHT5 eggs, dsCHT10 and dsCHT5/10 eggs exhibited failure of turnover of the serosal cuticle in which the horizontal chitinous laminae remained intact, resulting in lethal embryo hatching defects. These results indicate that group I CHT5 is essential for pupal-adult molting, whereas group II CHT10 plays an essential role in cuticular chitin degradation in T. castaneum during both embryonic hatching and all of the post-embryonic molts. CHT10 can serve in place of CHT5 in chitin degradation, except during the pupal-adult molt when both enzymes are indispensable to complete eclosion.

Using generalised additive models to visualise the annual cycle of primary feather moult patterns

Moult is a vital but energy-demanding event in a bird's phenological cycle. Primary moult is the shedding of old feathers and the regeneration of new flight feathers to maintain efficient functioning of these critical structures. Life history events, such as moult, breeding and migration, are typically separated from one another temporally because of the costs associated with moult Thus, extrapolation of other life-history events is possible from an understanding of the primary moult schedule in species for which data are easier to collect This study aimed to explore the primary moult patterns of nine nectarivorous species (seven Sunbirds and two Sugarbirds) using data extracted from the South African Bird Ringing Unit (SAFRING) database. Logistic generalised additive models (GAMs) were fitted to active/inactive moult observations to explore annual primary moult patterns. Breeding patterns based on the presence of brood patches in females were also analysed using GAMs for species with sufficient data. The GAMs illustrated the annual patterns well, with the probability of moult having clear peaks and troughs, allowing intuitive understanding of annual life-history patterns, such as the probability of breeding. Generally, GAMs hold potential to be used as a supplementary tool to study the timing of primary moult GAMs appear especially useful for species with no well-defined annual moult period.

The biosynthesis of alarm pheromone in the wheat aphid Rhopalo-siphum padi is regulated by hormones via fatty acid metabolism

Aphids are major insect pests in agriculture and forestry worldwide. Following attacks by natural enemies, many aphids release an alarm pheromone to protect their population. In most aphids, the main component of the aphid alarm pheromone (AAP) is the sesquiterpene hydrocarbon (E)-β-farnesene (EβF). However, the mechanisms behind its biosynthesis and regulation remain poorly understood. In this study, we used the bird cherry–oat aphid Rhopalosiphum padi, which is an important wheat aphid, to investigate the regulatory mechanisms of EβF biosynthesis. Our results showed that EβF biosynthesis occurs during the mature embryo period and the molting period of the 1st- and 2nd-instar nymphs. Triglycerides provide the prerequisite material for EβF production and release. Based on transcriptome sequencing, RNAi analysis, hormone treatments, and quantitative measurements, we found that the biosynthesis of EβF utilizes acetyl coenzyme A produced from fatty acid degradation, which can be suppressed by juvenile hormone but it is promoted by 20-hydroxyecdysone through the modulation of fatty acid metabolism. This is the first systemic study on the modulation of EβF production in aphids. The results of our study provide insights into the molecular regulatory mechanisms of AAP biosynthesis, as well as valuable information for designing potential aphid control strategies.

A demonstration of the value of recapture data for informing moult phenology models for avian species with imperfect moult data

The Underhill–Zucchini model has revolutionised the study of moult in the context of birds’ annual cycles, but, as for all statistical models, inferences are vulnerable to violations of model assumptions. In particular, the standard Underhill–Zucchini models for moult phenology are vulnerable to imperfect moult data arising, for example, from non-random sampling and/or the misclassification of non-moulting birds. Similarly, inference is challenging for species with dispersed moult periods (population-level moult extending beyond an annual cycle). Using ringing data from Cape Weavers Ploceus capensis and SAFRING data for Cape Sugarbirds Promerops cafer, we demonstrate how recent extensions to the Underhill–Zucchini framework can help the robust estimation of moult parameters in such situations, in particular when within-season recapture data is available.

Primary moult of adult Laughing Doves Spilopelia senegalensis: introduction of the relative duration index and a comparison of moult indices

A new moult index, the relative duration index (RDI), was developed to quantify progress through moult using the Underhill–Zucchini model of primary avian moult, with the Laughing Dove Spilopelia senegalensis as a case study. The RDI weights individual primaries in accordance with their estimated relative moult durations in the same way that proportion feather mass grown (PFMG) weights primaries in accordance with their relative masses. A sample of 1 893 moult records of adult Laughing Doves was used to study their primary moult. Moult parameters were estimated for three moult indices: the traditional moult score (TMS), PFMG and the RDI, and for each of the 10 primaries. Comparing the moult parameter estimates of each of the three indices to their respective cumulative growth curves obtained from the progression of moult of individual primaries, PFMG had the closest fit. However, any of the three moult indices would give satisfactory results for the Laughing Dove. Laughing Doves had an estimated primary moult duration of 215 days, with mean start and end dates of 3 November and 6 June, respectively. The standard deviation parameter was 66 days, which implies a lack of synchronisation of moult in adult doves. It was hypothesised that the RDI might be an appropriate moult index for species that moult one feather at a time and for which the individual moult durations are not proportional to their mass, as seen in Laughing Doves. However, this was not the case as PFMG provided the best fit. The RDI might also prove to be an appropriate moult index for species that moult multiple feathers simultaneously during part of the moult period and these feathers grow more slowly than when fewer feathers are moulting simultaneously.

Post‐colony swimming migration in the genus Uria

Seabirds within the Alcini subfamily have a unique breeding strategy, with their offspring leaving the colony flightless, at only a quarter of adult body size, accompanied by the father and fledge (become independent) out at sea. In this study we test several hypotheses about this elusive second part of the breeding season, termed swimming migration, for common guillemots Uria aalge and Brünnich's guillemots Uria lomvia by tracking 34 chicks (of which 17 transmitted data) equipped with satellite linked Argos PTTs (Platform Transmitter Terminals) at Bjørnøya, a major colony in the European Arctic. All chicks, presumably accompanied by their fathers, swam actively towards species‐specific autumn staging areas, rather than passively drifted away from the colony with a swim speed generally twice that observed of surrounding surface currents. They swam fastest during the first two days after departure. This coincides with the only time they actively crossed a current and the time needed to leave the area of prey depletion around the colony. They otherwise took advantage of available currents, while still swimming actively during the remainder of their migration towards species‐specific autumn staging areas. These staging areas corresponded to areas used by breeding adults during their moulting period (as confirmed by complementary light‐level logger tracking of adults), rather than being specific nursery areas. Migration duration correlated with distance resulting in species‐specific migration periods that were only a fraction of previously reported fledging periods out at sea, indicating that not only the swimming migration, but also known adult autumn staging regions constitute in effect breeding areas. This work has important implications for our understanding of population dynamics within the Alcini subfamily and the management of these species under multiple threats, while providing the foundation to investigate swimming migrations across their distributional range.

Seasonal changes in diel haul‐out patterns of a lacustrine ringed seal (Pusa hispida saimensis)

AbstractSeasonal changes in diel haul‐out patterns of the lacustrine Saimaa ringed seal (Pusa hispida saimensis) were studied using a combination of satellite telemetry and camera traps during 2007–2015. We found the haul‐out activity patterns to vary seasonally. Our results show that during the ice‐covered winter period before the seals start their annual molt, the peak in haul‐out generally occurs at midnight. Similarly, during the postmolt season of summer and autumn when the lake is free of ice, the haul‐out is concentrated in the early hours of the morning. In contrast, over the spring molting period, Saimaa ringed seals tend to haul out around the clock. The spring molt is also the only period when a slight difference in haul‐out behavior between the sexes is observed, with females having a haul‐out peak at nighttime while the males have a less visible diel pattern. According to our results, the diel haul‐out patterns of Saimaa ringed seals are similar to the ones of marine ringed seals. Gathering information on haul‐out activity is important in order to safeguard the natural patterns of Saimaa ringed seals in areas that are prone to disturbance from human activities.

Functional importance of groups I and II chitinases in cuticle chitin turnover during molting in a wood-boring beetle, Monochamus alternatus

Insects must periodically replace their old cuticle/exoskeleton with a new one in a process called molting or ecdysis to allow for continuous growth through sequential developmental stages. Many RNA interference (RNAi) studies have demonstrated that certain chitinases (CHTs) play roles in this vital physiological event because knockdown of these CHT genes resulted in developmental arrest during the ensuing molting period in several insect species. In this research we analyzed the functions of group I (MaCHT5) and group II (MaCHT10) CHT genes in molting of the Japanese pine sawyer, Monochamus alternatus, an important forest pest known as a major vector of the pinewood nematode. Real-time qPCR revealed that these two CHT genes differ in their expression patterns during late stages of development. Depletion of either MaCHT5 or MaCHT10 transcripts by RNAi resulted in lethal larval-pupal and pupal-adult molting defects depending on the double-stranded RNA (dsRNA) injection timing during development. The insects were unable to shed their old cuticle and died. Furthermore, transmission electron microscopic analysis revealed that, unlike dsEGFP-treated controls, dsMaCHT5- and dsMaCHT10-treated pharate adults exhibited a failure of degradation of the endocuticular layer of their old pupal cuticle, retaining nearly intact horizontal chitinous laminae and vertical pore canal fibers. Both enzymes were indispensable for complete turnover of the chitinous old endocuticle, which is critical for insect molting. The possible functions of two spliced variants of MaCHT10, namely, MaCHT10a and MaCHT10b, are also discussed. Our results add to the knowledge base for further functional studies of insect chitin catabolism by revealing the relative importance of both MaCHT5 and MaCHT10 in chitin turnover with subtle differences in their action. These essential genes and their encoded proteins are potential targets to manipulate for controlling populations of M. alternatus and other pest insects.

Genetic Control of Avian Migration: Insights from Studies in Latitudinal Passerine Migrants.

Twice-a-year, large-scale movement of billions of birds across latitudinal gradients is one of the most fascinating behavioral phenomena seen among animals. These seasonal voyages in autumn southwards and in spring northwards occur within a discrete time window and, as part of an overall annual itinerary, involve close interaction of the endogenous rhythm at several levels with prevailing photoperiod and temperature. The overall success of seasonal migrations thus depends on their close coupling with the other annual sub-cycles, namely those of the breeding, post-breeding recovery, molt and non-migratory periods. There are striking alterations in the daily behavior and physiology with the onset and end of the migratory period, as shown by the phase inversions in behavioral (a diurnal passerine bird becomes nocturnal and flies at night) and neural activities. Interestingly, there are also differences in the behavior, physiology and regulatory strategies between autumn and spring (vernal) migrations. Concurrent molecular changes occur in regulatory (brain) and metabolic (liver, flight muscle) tissues, as shown in the expression of genes particularly associated with 24 h timekeeping, fat accumulation and the overall metabolism. Here, we present insights into the genetic basis of migratory behavior based on studies using both candidate and global gene expression approaches in passerine migrants, with special reference to Palearctic-Indian migratory blackheaded and redheaded buntings.

Combinatorial expression of ebony and tan generates body color variation from nymph through adult stages in the cricket, Gryllus bimaculatus.

Insect body colors and patterns change markedly during development in some species as they adapt to their surroundings. The contribution of melanin and sclerotin pigments, both of which are synthesized from dopamine, to cuticle tanning has been well studied. Nevertheless, little is known about how insects alter their body color patterns. To investigate this mechanism, the cricket Gryllus bimaculatus, whose body color patterns change during postembryonic development, was used as a model in this study. We focused on the ebony and tan genes, which encode enzymes that catalyze the synthesis and degradation, respectively, of the precursor of yellow sclerotin N-β-alanyl dopamine (NBAD). Expression of the G. bimaculatus (Gb) ebony and tan transcripts tended to be elevated just after hatching and the molting period. We found that dynamic alterations in the combined expression levels of Gb'ebony and Gb'tan correlated with the body color transition from the nymphal stages to the adult. The body color of Gb'ebony knockout mutants generated by CRISPR/Cas9 systemically darkened. Meanwhile, Gb'tan knockout mutants displayed a yellow color in certain areas and stages. The phenotypes of the Gb'ebony and Gb'tan mutants probably result from an over-production of melanin and yellow sclerotin NBAD, respectively. Overall, stage-specific body color patterns in the postembryonic stages of the cricket are governed by the combinatorial expression of Gb'ebony and Gb'tan. Our findings provide insights into the mechanism by which insects evolve adaptive body coloration at each developmental stage.