Zygosity-based sex determination in a butterfly drives hypervariability of Masculinizer.

Nature has devised many ways of producing males and females. Here, we report on a previously undescribed mechanism for Lepidoptera that functions without a female-specific gene. The number of alleles or allele heterozygosity in a single Z-linked gene (BaMasc) is the primary sex-determining switch in Bicyclus anynana butterflies. Embryos carrying a single BaMasc allele develop into WZ (or Z0) females, those carrying two distinct alleles develop into ZZ males, while (ZZ) homozygotes initiate female development, have mismatched dosage compensation, and die as embryos. Consequently, selection against homozygotes has favored the evolution of spectacular allelic diversity: 205 different coding sequences of BaMasc were detected in a sample of 246 females. The structural similarity of a hypervariable region (HVR) in BaMasc to the HVR in Apis mellifera csd suggests molecular convergence between deeply diverged insect lineages. Our discovery of this primary switch highlights the fascinating diversity of sex-determining mechanisms and underlying evolutionary drivers.

Phenotypic plasticity in tropical butterflies is linked to climatic seasonality on a macroevolutionary scale.

Phenotypic plasticity can be adaptive in fluctuating environments by providing rapid environment-phenotype matching and this applies particularly in seasonal environments. African Bicyclus butterflies have repeatedly colonized seasonal savannahs from ancestral forests around the Late Miocene and many species now exhibit seasonal polyphenism. On a macroevolutionary scale, it can be expected that savannah species will exhibit higher plasticity due to them experiencing stronger environmental seasonality than forest species. We quantified seasonality using environmental niche modelling, and surveyed the degree of plasticity in a key wing pattern element (eyespot size) using museum specimens. We show that species occurring in highly seasonal environments display strong plasticity, while species in less seasonal or aseasonal environments exhibit surprisingly variable degrees of plasticity, including strong to no plasticity. Furthermore, eyespot size plasticity has a moderate phylogenetic signal and the ancestral Bicyclus likely exhibited some degree of plasticity. We propose hypotheses to explain the range of plasticity patterns seen in less seasonal environments, and generate testable predictions for the evolution of plasticity in Bicyclus. Our study provides one of the most compelling cases showing links between seasonality and phenotypic plasticity on a macroevolutionary scale and the potential role of plasticity in facilitating the colonization of novel environments.

Miocene Climate and Habitat Change Drove Diversification in Bicyclus, Africa's Largest Radiation of Satyrine Butterflies.

Compared to other regions, the drivers of diversification in Africa are poorly understood. We studied a radiation of insects with over 100 species occurring in a wide range of habitats across the Afrotropics to investigate the fundamental evolutionary processes and geological events that generate and maintain patterns of species richness on the continent. By investigating the evolutionary history of Bicyclus butterflies within a phylogenetic framework, we inferred the group's origin at the Oligo-Miocene boundary from ancestors in the Congolian rainforests of central Africa. Abrupt climatic fluctuations during the Miocene (ca. 19-17 Ma) likely fragmented ancestral populations, resulting in at least eight early-divergent lineages. Only one of these lineages appears to have diversified during the drastic climate and biome changes of the early Miocene, radiating into the largest group of extant species. The other seven lineages diversified in forest ecosystems during the late Miocene and Pleistocene when climatic conditions were more favorable-warmer and wetter. Our results suggest changing Neogene climate, uplift of eastern African orogens, and biotic interactions have had different effects on the various subclades of Bicyclus, producing one of the most spectacular butterfly radiations in Africa. [Afrotropics; biodiversity; biome; biotic interactions; Court Jester; extinction; grasslands; paleoclimates; Red Queen; refugia forests; dependent-diversification; speciation.].

Predictability of temporal variation in climate and the evolution of seasonal polyphenism in tropical butterfly communities.

Phenotypic plasticity in heterogeneous environments can provide tight environment-phenotype matching. However, the prerequisite is a reliable environmental cue(s) that enables organisms to use current environmental information to induce the development of a phenotype with high fitness in a forthcoming environment. Here, we quantify predictability in the timing of precipitation and temperature change to examine how this is associated with seasonal polyphenism in tropical Mycalesina butterflies. Seasonal precipitation in the tropics typically results in distinct selective environments, the wet and dry seasons, and changes in temperature can be a major environmental cue. We sampled communities of Mycalesina butterflies from two seasonal locations and one aseasonal location. Quantifying environmental predictability using wavelet analysis and Colwell's indices confirmed a strong periodicity of precipitation over a 12-month period at both seasonal locations compared to the aseasonal one. However, temperature seasonality and periodicity differed between the two seasonal locations. We further show that: (a) most females from both seasonal locations synchronize their reproduction with the seasons by breeding in the wet season but arresting reproduction in the dry season. In contrast, all species breed throughout the year in the aseasonal location and (b) species from the seasonal locations, but not those from the aseasonal location, exhibited polyphenism in wing pattern traits (eyespot size). We conclude that seasonal precipitation and its predictability are primary factors shaping the evolution of polyphenism in Mycalesina butterflies, and populations or species secondarily evolve local adaptations for cue use that depend on the local variation in the environment.

Seasonal environments drive convergent evolution of a faster pace-of-life in tropical butterflies.

New ecological niches that may arise due to climate change can trigger diversification, but their colonisation often requires adaptations in a suite of life-history traits. We test this hypothesis in species-rich Mycalesina butterflies that have undergone parallel radiations in Africa, Asia, and Madagascar. First, our ancestral state reconstruction of habitat preference, using c. 85% of extant species, revealed that early forest-linked lineages began to invade seasonal savannahs during the late Miocene-Pliocene. Second, rearing replicate pairs of forest and savannah species from the African and Malagasy radiation in a common garden experiment, and utilising published data from the Asian radiation, demonstrated that savannah species consistently develop faster, have smaller bodies, higher fecundity with an earlier investment in reproduction, and reduced longevity, compared to forest species across all three radiations. We argue that time-constraints for reproduction favoured the evolution of a faster pace-of-life in savannah species that facilitated their persistence in seasonal habitats.

A release from developmental bias accelerates morphological diversification in butterfly eyespots.

Development can bias the independent evolution of traits sharing ontogenetic pathways, making certain evolutionary changes less likely. The eyespots commonly found on butterfly wings each have concentric rings of differing colors, and these serially repeated pattern elements have been a focus for evo-devo research. In the butterfly family Nymphalidae, eyespots have been shown to function in startling or deflecting predators and to be involved in sexual selection. Previous work on a model species of Mycalesina butterfly, Bicyclus anynana, has provided insights into the developmental control of the size and color composition of individual eyespots. Experimental evolution has also shown that the relative size of a pair of eyespots on the same wing surface is highly flexible, whereas they are resistant to diverging in color composition, presumably due to the underlying shared developmental process. This fixed color composition has been considered as a prime example of developmental bias with significant consequences for wing pattern evolution. Here, we test this proposal by surveying eyespots across the whole subtribe of Mycalesina butterflies and demonstrate that developmental bias shapes evolutionary diversification except in the genus Heteropsis which has gained independent control of eyespot color composition. Experimental manipulations of pupal wings reveal that the bias has been released through a novel regional response of the wing tissue to a conserved patterning signal. Our study demonstrates that development can bias the evolutionary independence of traits, but it also shows how bias can be released through developmental innovations, thus, allowing rapid morphological change, facilitating evolutionary diversification.

To mate, or not to mate: The evolution of reproductive diapause facilitates insect radiation into African savannahs in the Late Miocene.

Many tropical environments experience cyclical seasonal changes, frequently with pronounced wet and dry seasons, leading to a highly uneven temporal distribution of resources. Short-lived animals inhabiting such environments often show season-specific adaptations to cope with alternating selection pressures. African Bicyclus butterflies show strong seasonal polyphenism in a suite of phenotypic and life-history traits, and their adults are thought to undergo reproductive diapause associated with the lack of available larval host plants during the dry season. Using 3 years of longitudinal field data for three species in Malawi, dissections demonstrated that one forest species reproduces continuously, whereas two savannah species undergo reproductive diapause in the dry season, either with or without pre-diapause mating. Using additional data from field-collected and museum samples, we then documented the same three mating strategies for a further 37 species. Phylogenetic analyses indicated that the ancestral state was a non-diapausing forest species, and that habitat preference and mating strategy evolved in a correlated fashion. Bicyclus butterflies underwent rapid diversification during the Late Miocene, coinciding with expansions into more open savannah habitat. We conclude that the ability to undergo reproductive diapause was a key trait that facilitated colonization and eventual radiation into savannahs in the Late Miocene.

Sexual selection contributes to partial restoration of phenotypic robustness in a butterfly.

Phenotypic variation is the raw material for selection that is ubiquitous for most traits in natural populations, yet the processes underlying phenotypic evolution or stasis often remain unclear. Here, we report phenotypic evolution in a mutant line of the butterfly Bicyclus anynana after outcrossing with the genetically polymorphic wild type population. The comet mutation modifies two phenotypic traits known to be under sexual selection in this butterfly: the dorsal forewing eyespots and the pheromone-producing structures. The original comet mutant line was inbred and remained phenotypically stable for at least seven years, but when outcrossed to the wild type population the outcrossed comet line surprisingly recovered the wild type phenotype within 8 generations at high (27 °C), but not at low (20 °C), developmental temperatures. Male mating success experiments then revealed that outcrossed comet males with the typical comet phenotype suffered from lower mating success, while mating success of outcrossed comet males resembling wild types was partially restored. We document a fortuitous case where the addition of genetic polymorphism around a spontaneous mutation could have allowed partial restoration of phenotypic robustness. We further argue that sexual selection through mate choice is likely the driving force leading to phenotypic robustness in our system.

Developmental Bias and Evolution: A Regulatory Network Perspective.

Phenotypic variation is generated by the processes of development, with some variants arising more readily than others-a phenomenon known as "developmental bias." Developmental bias and natural selection have often been portrayed as alternative explanations, but this is a false dichotomy: developmental bias can evolve through natural selection, and bias and selection jointly influence phenotypic evolution. Here, we briefly review the evidence for developmental bias and illustrate how it is studied empirically. We describe recent theory on regulatory networks that explains why the influence of genetic and environmental perturbation on phenotypes is typically not uniform, and may even be biased toward adaptive phenotypic variation. We show how bias produced by developmental processes constitutes an evolving property able to impose direction on adaptive evolution and influence patterns of taxonomic and phenotypic diversity. Taking these considerations together, we argue that it is not sufficient to accommodate developmental bias into evolutionary theory merely as a constraint on evolutionary adaptation. The influence of natural selection in shaping developmental bias, and conversely, the influence of developmental bias in shaping subsequent opportunities for adaptation, requires mechanistic models of development to be expanded and incorporated into evolutionary theory. A regulatory network perspective on phenotypic evolution thus helps to integrate the generation of phenotypic variation with natural selection, leaving evolutionary biology better placed to explain how organisms adapt and diversify.

Pervasive gene expression responses to a fluctuating diet in Drosophila melanogaster: The importance of measuring multiple traits to decouple potential mediators of life span and reproduction.

Phenotypic plasticity is an important concept in life-history evolution, and most organisms, including Drosophila melanogaster, show a plastic life-history response to diet. However, little is known about how these life-history responses are mediated. In this study, we compared adult female flies fed an alternating diet (yoyo flies) with flies fed a constant low (CL) or high (CH) diet and tested how whole genome expression was affected by these diet regimes and how the transcriptional responses related to different life-history traits. We showed that flies were able to respond quickly to diet fluctuations throughout life span by drastically changing their transcription. Importantly, by measuring the response of multiple life-history traits we were able to decouple groups of genes associated with life span or reproduction, life-history traits that often covary with a diet change. A coexpression network analysis uncovered which genes underpin the separate and shared regulation of these life-history traits. Our study provides essential insights to help unravel the genetic architecture mediating life-history responses to diet, and it shows that the flies' whole genome transcription response is highly plastic.

A high-coverage draft genome of the mycalesine butterfly Bicyclus anynana.

The mycalesine butterfly Bicyclus anynana, the "Squinting bush brown," is a model organism in the study of lepidopteran ecology, development, and evolution. Here, we present a draft genome sequence for B. anynana to serve as a genomics resource for current and future studies of this important model species. Seven libraries with insert sizes ranging from 350 bp to 20 kb were constructed using DNA from an inbred female and sequenced using both Illumina and PacBio technology; 128 Gb of raw Illumina data was filtered to 124 Gb and assembled to a final size of 475 Mb (∼×260 assembly coverage). Contigs were scaffolded using mate-pair, transcriptome, and PacBio data into 10 800 sequences with an N50 of 638 kb (longest scaffold 5 Mb). The genome is comprised of 26% repetitive elements and encodes a total of 22 642 predicted protein-coding genes. Recovery of a BUSCO set of core metazoan genes was almost complete (98%). Overall, these metrics compare well with other recently published lepidopteran genomes. We report a high-quality draft genome sequence for Bicyclus anynana. The genome assembly and annotated gene models are available at LepBase (http://ensembl.lepbase.org/index.html).

Conserved patterns of integrated developmental plasticity in a group of polyphenic tropical butterflies.

BACKGROUND: Developmental plasticity is thought to have profound macro-evolutionary effects, for example, by increasing the probability of establishment in new environments and subsequent divergence into independently evolving lineages. In contrast to plasticity optimized for individual traits, phenotypic integration, which enables a concerted response of plastic traits to environmental variability, may affect the rate of local adaptation by constraining independent responses of traits to selection. Using a comparative framework, this study explores the evolution of reaction norms for a variety of life history and morphological traits across five related species of mycalesine butterflies from the Old World tropics. RESULTS: Our data indicate that an integrated response of a suite of key traits is shared amongst these species. Interestingly, the traits that make up the functional suite are all known to be regulated by ecdysteroid signalling in Bicyclus anynana, one of the species included in this study, suggesting the same underlying hormonal regulator may be conserved within this group of polyphenic butterflies. We also detect developmental thresholds for the expression of alternative morphs. CONCLUSIONS: The phenotypic plasticity of a broad suite of morphological and life history traits is integrated and shared among species from three geographically independent lineages of mycalesine butterflies, despite considerable periods of independent evolution and exposure to disparate environments. At the same time, we have detected examples of evolutionary change where independent traits show different patterns of reaction norms. We argue that the expression of more robust phenotypes may occur by shifting developmental thresholds beyond the boundaries of the typical environmental variation.

Growing more positive with age: The relationship between reproduction and survival in aging flies.

Populations of laboratory animals that are selected for increased lifespan often show negative correlated responses in early fecundity. However, late fecundity and/or total lifetime fecundity can be higher in the populations selected for increased lifespan. This has been interpreted by some as being at odds with the disposable soma theory, which predicts decreased lifespan to increase total reproductive output. Alternatively, the Y-model explores the effects of variation in resource allocation and acquisition on life histories. In this model, a negative relationship between lifespan and reproduction can be viewed as variation in allocation, whereas a positive relationship is the result of variation in acquisition. However, a frequently neglected complication of the Y-model is that older individuals often show a decline in resource acquisition. Therefore, differential allocation to maintenance and survival might affect this decline in late-life acquisition which will affect resource availability across the whole lifespan. In this paper we show that a model which incorporates the ideas of the Y-model, the disposable soma theory, and an age-related decrease in resource acquisition, i.e. feeding senescence, can explain how the relationship between fecundity and lifespan changes with age. Furthermore, by modeling environments with contrasting extrinsic mortality rates, we explored how the outcome of the model depended on the relative importance of early and late-life reproduction. In high mortality environments a relatively higher early fecundity, lower late fecundity, and lower lifespans were more optimal, whereas the opposite was true for low mortality environments. We applied predictions from the model to a cohort of individually-housed female Drosophila melanogaster flies for which we measured age specific fecundity and lifespan. Early fecundity was negatively associated with lifespan, while late fecundity related positively with lifespan in the same cohort. This verified that the mechanism of feeding senescence could explain patterns for age specific relationships between lifespan and fecundity.

Differentiation in putative male sex pheromone components across and within populations of the African butterfly Bicyclus anynana as a potential driver of reproductive isolation.

Sexual traits are often the most divergent characters among closely related species, suggesting an important role of sexual traits in speciation. However, to prove this, we need to show that sexual trait differences accumulate before or during the speciation process, rather than being a consequence of it. Here, we contrast patterns of divergence among putative male sex pheromone (pMSP) composition and the genetic structure inferred from variation in the mitochondrial cytochrome oxidase 1 and nuclear CAD loci in the African butterfly Bicyclus anynana (Butler, 1879) to determine whether the evolution of "pheromonal dialects" occurs before or after the differentiation process. We observed differences in abundance of some shared pMSP components as well as differences in the composition of the pMSP among B. anynana populations. In addition, B. anynana individuals from Kenya displayed differences in the pMSP composition within a single population that appeared not associated with genetic differences. These differences in pMSP composition both between and within B. anynana populations were as large as those found between different Bicyclus species. Our results suggest that "pheromonal dialects" evolved within and among populations of B. anynana and may therefore act as precursors of an ongoing speciation process.

Preference for C4 shade grasses increases hatchling performance in the butterfly, Bicyclus safitza.

The Miocene radiation of C4 grasses under high-temperature and low ambient CO 2 levels occurred alongside the transformation of a largely forested landscape into savanna. This inevitably changed the host plant regime of herbivores, and the simultaneous diversification of many consumer lineages, including Bicyclus butterflies in Africa, suggests that the radiations of grasses and grazers may be evolutionary linked. We examined mechanisms for this plant-herbivore interaction with the grass-feeding Bicyclus safitza in South Africa. In a controlled environment, we tested oviposition preference and hatchling performance on local grasses with C3 or C4 photosynthetic pathways that grow either in open or shaded habitats. We predicted preference for C3 plants due to a hypothesized lower processing cost and higher palatability to herbivores. In contrast, we found that females preferred C4 shade grasses rather than either C4 grasses from open habitats or C3 grasses. The oviposition preference broadly followed hatchling performance, although hatchling survival was equally good on C4 or C3 shade grasses. This finding was explained by leaf toughness; shade grasses were softer than grasses from open habitats. Field monitoring revealed a preference of adults for shaded habitats, and stable isotope analysis of field-sampled individuals confirmed their preference for C4 grasses as host plants. Our findings suggest that plant-herbivore interactions can influence the direction of selection in a grass-feeding butterfly. Based on this work, we postulate future research to test whether these interactions more generally contribute to radiations in herbivorous insects via expansions into new, unexploited ecological niches.

Revision of the Bicyclus sciathis species group (Lepidoptera: Nymphalidae) with descriptions of four new species and corrected distributional records.

In this paper we present a thorough revision of the sciathis species group of the butterfly genus Bicyclus (Kirby). Type materials are discussed and in several cases lectotypes are assigned to specimens from original type series. Four new, and morphologically distinct, species are described (B. elishiae Brattström sp.n., B. heathi Brattström sp.n., B. sigiussidorum Brattström sp.n. and B. subtilisurae Brattström sp.n.), along with a comprehensive molecular phylogeny that includes exemplar taxa of all currently recognized species. We also investigate the types of all previously synonymized taxa and in the process invalidate the name B. ewondo Libert. This was done after finding the previously missing holotype of B. makomensis (Strand), which clearly belongs to the same species and thereby gives the older name priority. The phylogeny showed that some distinctly different species were surprisingly closely related, suggesting a high rate of morphological evolution in parts of the sciathis group. The distributional records for the group are updated after investigating over 1700 specimens kept in a range of museum collections. Many species previously thought to be broadly sympatric were found to have much more restricted ranges, with the previous overestimations probably based on misidentified specimens. The higher level of allopatry now established will make identification of many morphologically similar species easier. The fact that species often have smaller ranges than previously known, meaning that the level of endemism for African butterflies is likely to be higher than current estimates, has important implications for conservation management. An identification key for males of all 13 currently recognized species in the species group is included. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:837A9D4C-779A-4497-8176-7151D409DFA5.

Revision of the Bicyclus ignobilis species-group (Lepidoptera: Nymphalidae: Satyrinae) with descriptions of two new species.

The ignobilis-group of the genus Bicyclus Kirby 1871 is revised. The species-group contains six species with a distinct wing pattern, but limited intraspecific variation, distributed across tropical African rainforest. We investigate a set of more than 1000 specimens from a range of museum collections, including some type material, and thoroughly update the biogeographical knowledge for the group. We also describe two new species as members of the group. The included species are: Bicyclus ignobilis (Butler 1870) stat. rev., B. rileyi Condamin 1961, B. maesseni Condamin 1971, B. brakefieldi Brattström 2012, B. ottossoni sp. nov. and B. vandeweghei sp. nov. Due to observing a gradual morphological cline within B. ignobilis without any sharp transitions we suppress the previously identified subspecies B. ignobilis eurini Condamin & Fox 1963 syn. nov. and B. ignobilis acutus Condamin 1965 syn. nov.

Systematics and historical biogeography of the old world butterfly subtribe Mycalesina (Lepidoptera: Nymphalidae: Satyrinae).

BACKGROUND: Butterflies of the subtribe Mycalesina have radiated successfully in almost all habitat types in Africa, Madagascar, the Indian subcontinent, Indo-China and Australasia. Studies aimed at understanding the reasons behind the evolutionary success of this spectacular Old World butterfly radiation have been hampered by the lack of a stable phylogeny for the group. Here, we have reconstructed a robust phylogenetic framework for the subtribe using 10 genes from 195 exemplar taxa. RESULTS: We recovered seven well supported clades within the subtribe corresponding to the five traditional genera (Lohora, Heteropsis, Hallelesis, Bicyclus, Mycalesis), one as recently revised (Mydosama) and one newly revised genus (Culapa). The phylogenetic relationships of these mycalesine genera have been robustly established for the first time. Within the proposed phylogenetic framework, we estimated the crown age of the subtribe to be 40 Million years ago (Mya) and inferred its ultimate origin to be in Asia. Our results reveal both vicariance and dispersal as factors responsible for the current widespread distribution of the group in the Old World tropics. We inferred that the African continent has been colonized at least twice by Asian mycalesines within the last 26 and 23 Mya. In one possible scenario, an Asian ancestor gave rise to Heteropsis on continental Africa, which later dispersed into Madagascar and most likely back colonised Asia. The second colonization of Africa by Asian ancestors resulted in Hallelesis and Bicyclus on continental Africa, the descendants of which did not colonise other regions but rather diversified only in continental Africa. The genera Lohora and Mydosama are derivatives of ancestors from continental Asia. CONCLUSION: Our proposed time-calibrated phylogeny now provides a solid framework within which we can implement mechanistic studies aimed at unravelling the ecological and evolutionary processes that culminated in the spectacular radiation of mycalesines in the Old World tropics.

Adaptive developmental plasticity: compartmentalized responses to environmental cues and to corresponding internal signals provide phenotypic flexibility.

BACKGROUND: The environmental regulation of development can result in the production of distinct phenotypes from the same genotype and provide the means for organisms to cope with environmental heterogeneity. The effect of the environment on developmental outcomes is typically mediated by hormonal signals which convey information about external cues to the developing tissues. While such plasticity is a wide-spread property of development, not all developing tissues are equally plastic. To understand how organisms integrate environmental input into coherent adult phenotypes, we must know how different body parts respond, independently or in concert, to external cues and to the corresponding internal signals. RESULTS: We quantified the effect of temperature and ecdysone hormone manipulations on post-growth tissue patterning in an experimental model of adaptive developmental plasticity, the butterfly Bicyclus anynana. Following a suite of traits evolving by natural or sexual selection, we found that different groups of cells within the same tissue have sensitivities and patterns of response that are surprisingly distinct for the external environmental cue and for the internal hormonal signal. All but those wing traits presumably involved in mate choice responded to developmental temperature and, of those, all but the wing traits not exposed to predators responded to hormone manipulations. On the other hand, while patterns of significant response to temperature contrasted traits on autonomously-developing wings, significant response to hormone manipulations contrasted neighboring groups of cells with distinct color fates. We also showed that the spatial compartmentalization of these responses cannot be explained by the spatial or temporal compartmentalization of the hormone receptor protein. CONCLUSIONS: Our results unravel the integration of different aspects of the adult phenotype into developmental and functional units which both reflect and impact evolutionary change. Importantly, our findings underscore the complexity of the interactions between environment and physiology in shaping the development of different body parts.

On the fate of seasonally plastic traits in a rainforest butterfly under relaxed selection.

Many organisms display phenotypic plasticity as adaptation to seasonal environmental fluctuations. Often, such seasonal responses entails plasticity of a whole suite of morphological and life-history traits that together contribute to the adaptive phenotypes in the alternative environments. While phenotypic plasticity in general is a well-studied phenomenon, little is known about the evolutionary fate of plastic responses if natural selection on plasticity is relaxed. Here, we study whether the presumed ancestral seasonal plasticity of the rainforest butterfly Bicyclus sanaos (Fabricius, 1793) is still retained despite the fact that this species inhabits an environmentally stable habitat. Being exposed to an atypical range of temperatures in the laboratory revealed hidden reaction norms for several traits, including wing pattern. In contrast, reproductive body allocation has lost the plastic response. In the savannah butterfly, B. anynana (Butler, 1879), these traits show strong developmental plasticity as an adaptation to the contrasting environments of its seasonal habitat and they are coordinated via a common developmental hormonal system. Our results for B. sanaos indicate that such integration of plastic traits - as a result of past selection on expressing a coordinated environmental response - can be broken when the optimal reaction norms for those traits diverge in a new environment.