Tropical Butterfly Research Articles

The Impact of Plant Diversity on Spider Populations in a Tropical Butterfly Conservatory, Tiruchirappalli, South India

Spiders, as crucial predators and biodiversity indicators, significantly influence ecosystem health. This study investigates the intricate relationship between plant diversity and spider communities within distinct habitats of the Tropical Butterfly Conservatory, Tiruchirappalli, India. By classifying spiders based on their hunting strategies, we aim to understand their ecological roles. This research establishes a baseline for the spider fauna within the conservatory, emphasizing the impact of plant life on spider diversity and distribution. Our findings contribute to a comprehensive evaluation of the ecological importance of spiders in this unique ecosystem, providing valuable insights for future conservation and management efforts. By unravelling the complex interplay between plants and spiders, this study underscores the necessity of preserving plant diversity to sustain a robust and balanced spider community.

Nanostructural Influence on Optical and Thermal Properties of Butterfly Wing Scales Across Forest Vertical Strata.

Butterfly wing scales feature complex nanostructures that influence wing coloration and various mechanical and optical properties. This configuration plays a key role in ecological interactions, flight conditions, and thermoregulation, facilitated by interactions with environmental electromagnetic energy. In tropical forests, butterflies occupy distinct vertical habitats, experiencing significant light and temperature variations. While wing nanostructures have been widely studied, their variation across different vertical flight preferences remains underexplored. This study investigates the wing nanostructures of 12 tropical butterfly species from the Nymphalidae family, focusing on their optical, morphological, and thermal properties across different forest strata. We analyzed the optical response through diffuse reflectance in the UV, Vis, and NIR ranges, correlating these findings with nanostructural configuration and thermal stability using thermogravimetric analysis (TGA). Our results reveal a significant correlation between flight stratification and wing optical responses, alongside distinct nanostructural features within each stratum. This study demonstrates the variability in butterfly wing nanostructures along the vertical stratification of the forest to cope with environmental conditions, raising new questions for future research on eco-evolutionary flight and thermal adaptations. Additionally, this underscores the importance of understanding how these structural adaptations influence butterfly interactions with their environment and their evolutionary success across different forest strata.

Blind measurements did not confirm effects of forest fragmentation on fluctuating asymmetry of a tropical butterfly Morpho helenor

Re-evaluation of photographs of the tropical butterfly Morpho helenor from a previous study (Pignataro et al. 2023) revealed that its conclusion regarding increased wing fluctuating asymmetry in forest edge habitats compared to forest interior habitats could not be replicated. This discrepancy likely arises from (i) original measurements not being conducted blindly, (ii) insufficient photograph quality hindering accurate landmark selection, and (iii) a lack of detailed description of the measurement protocol. The likelihood of false positive discoveries within the published data concerning the impacts of environmental stress on the fluctuating asymmetry of plants and animals is probably higher than previously assumed.

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 because of experiencing stronger environmental seasonality than forest species. We quantified seasonality using environmental niche modeling and surveyed the degree of plasticity in a key wing pattern element (eyespot size) using museum specimens. We showed 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.

Succession and seasonality drive tropical butterfly assembly after an extreme hurricane

AbstractThe composition and biodiversity of insect community assemblages are mediated by a complex set of biotic and abiotic factors. Among these factors are forest structure and atmospheric variables (like temperature and humidity), which are heavily influenced by frequent hurricane activity in the Caribbean. Despite this, changes in Caribbean insect assemblages as forests recover from hurricane disturbance are poorly documented. Butterflies represent a charismatic model taxon in biodiversity and conservation, and are thus an ideal subject for exemplifying these shifts in insect abundances and diversity across ecological succession. Here, we monitored butterfly communities in two Puerto Rican forests differing in structure (i.e., canopy height, tree size) to assess butterfly diversity, abundances, and community level wing traits (size and color) over 1 year, beginning 6 months after Hurricane Maria. Monthly sampling over the course of 1 year revealed no relationships between abundances and canopy openness or humidity; instead, species abundances fluctuated seasonally and were nonlinearly correlated with temperature. In contrast, wing size and color were linearly correlated with abiotic variables. Specifically, wings were larger in cooler and more open conditions. Wing color saturation and brightness were negatively correlated with humidity. Our results suggest that, first, a functional approach may provide better insight into the factors mediating species responses to disturbances. Second, further disentangling abundance seasonality from impacts of extreme disturbances necessitates long‐term monitoring.Abstract in Spanish is available with online material.

Heat stress reduced survival but sped up development in Heliconius erato butterflies

AbstractAnthropogenic climate change is thought to present a significant threat to biodiversity, in particular to tropical ectotherms, and the effects of long‐term developmental heat stress on this group have received relatively little research attention. Here, we studied the effects of experimentally raising developmental temperatures on a tropical butterfly. We measured survival, development time, adult body mass and wing size of Heliconius erato demophoon (Linnaeus) (Lepidoptera: Nymphalidae) across three temperature treatments. Egg survival was lower in the hotter treatments, with 84%, 73% and 49% of eggs hatching in the 20–30°C (fluctuating temperature with 12 h at 20°C followed by 12 h at 30°C), 23–33°C and 26–36°C treatments, respectively. Larval survival was three times lower in the 26–36°C treatment (8%) compared with the 20–30°C treatment (26%), and we did not detect differences in pupal survival across treatments due to high mortality in earlier stages. Under a moderately increased temperature at 23–33°C, larvae developed faster and adults had a higher body mass and wing loading, but this was not seen in the hottest treatment (26–36°C). Females were also heavier than males in the 23–33°C treatment, but there was no associated increase in wing size. This may suggest a different developmental response to moderately elevated temperatures between the sexes. In summary, high developmental temperatures are particularly lethal for eggs and less so for larvae and also affect adult morphology. This highlights the importance of understanding the effects of temperature variation across ontogeny in tropical ectotherms.

Temperature seasonality drives taxonomic and functional homogenization of tropical butterflies

AbstractAimTo better understand the potential impact of climate change on butterfly assemblages across a tropical island, we model the potential for taxonomic and functional homogenization and determine climate‐ and trait‐mediated shifts in projected species distributions.LocationPuerto Rico.MethodsWe used thousands of museum records of diurnal Lepidoptera to model current (1970–2000) and forecast future (2061–2080) species distributions and combined these to test for taxonomic and functional homogenization. We then quantified climatic‐mediated effects on current and forecasted taxonomic and functional composition and, specifically, whether temperature was a primary driver, as predicted by the temperature–size rule and the thermal melanism hypotheses. Finally, we measured wing traits important in thermoregulation (size and colour) and determined trait‐mediated changes in forecasted species distributions over time.ResultsBased on ensemble model outputs, taxonomic and functional richness and turnover were predicted to vary across the island's complex topography. Our models projected an increase in taxonomic and functional richness over time, and a decrease in taxonomic and functional turnover – a signature of biotic homogenization. Under future climate scenarios, models projected a decrease in wing length and an increase in wing brightness at higher elevations. One variable, temperature seasonality, was the strongest predicted driver of both the current spatial distribution and the projected per cent change over time for not only wing traits but also taxonomic and functional richness and turnover.Main conclusionsThe species distribution models generated here identify several priority regions and species for future research and conservation efforts. Our work also highlights the role of seasonality and climatic variability on diverse tropical Lepidoptera assemblages, suggesting that climatic variability may be an important, albeit overlooked, driver of climate change responses.

Divergent warning patterns influence male and female mating behaviours in a tropical butterfly.

Traits under divergent ecological selection that also function during mating can be important in maintaining species boundaries. Few studies have considered mutual mate choice, where both males and females base mating decisions on the same trait. Wing colouration in Heliconius butterflies evolved as a warning signal but also functions as a mating cue. We investigated the contribution of visual preference to assortative mating in an aposematic butterfly Heliconius cydno in the context of reproductive isolation with its sympatric, visually distinct relative Heliconius melpomene. Heliconius cydno have conspicuous white bands on their forewings, whereas those of H. melpomene are red in colour. We predicted that both sexes of H. cydno contributed to assortative mating by exhibiting visual preference towards conspecific wing colouration. We analysed published and new data from preference experiments, in which males were presented with conspecific and H. melpomene females. We also recorded female responses and mating outcomes in choice experiments, involving conspecific males with either the original white or artificially painted red forewing bands. Both sexes of H. cydno responded more positively towards the conspecific colouration, and males strongly preferred females of its own colours. In contrast, male colouration did not predict mating outcomes in female choice experiments. As courtships are initiated by males in butterflies, our findings suggest that female visual preference might be of secondary importance in H. cydno. Our data also suggest that the contribution of visual preference to reproductive isolation might be unequal between H. cydno and its sympatric relative H. melpomene.

On the presence of two tropical butterflies (Lepidoptera Nymphalidae) in the city of Palermo (Italy)

On the presence of two tropical butterflies (Lepidoptera Nymphalidae) in the city of Palermo (Italy)

Butterfly community composition within a tropical urban landscape is influenced by habitat type and temperature

Abstract The specific factors that influence spatial community or population dynamics are often elusive, and even less known is the impact of tropical urban landscapes on diverse species community assemblages. To address this knowledge gap, we used a survey data set with 510 fruit‐feeding butterflies comprising 20 species across two heterogeneous habitats within a city in Nigeria. Next, we constructed generalised linear mixed models to understand the differential responses of the butterfly community to changes in environmental conditions across habitats. Butterfly species community assemblages significantly differed between the two urban habitats, with butterfly species significantly higher in the savannah woodland compared with the gallery forest due to the optimal daily temperatures of the savannah woodland. However, butterfly richness was lower in the gallery forest due to extreme environmental conditions. This study highlights that butterfly community changes in tropical urban landscapes are possibly responding to local microclimates and spatial heterogeneity across habitats. For evidence‐based conservation management of tropical butterfly biodiversity, there would be need for a long‐term, extensive and systematic insect monitoring programme for butterflies across disturbed and undisturbed fragmented habitats harbouring diverse insect species.

Demographically explicit scans for barriers to gene flow using gIMble.

Identifying regions of the genome that act as barriers to gene flow between recently diverged taxa has remained challenging given the many evolutionary forces that generate variation in genetic diversity and divergence along the genome, and the stochastic nature of this variation. Progress has been impeded by a conceptual and methodological divide between analyses that infer the demographic history of speciation and genome scans aimed at identifying locally maladaptive alleles i.e. genomic barriers to gene flow. Here we implement genomewide IM blockwise likelihood estimation (gIMble), a composite likelihood approach for the quantification of barriers, that bridges this divide. This analytic framework captures background selection and selection against barriers in a model of isolation with migration (IM) as heterogeneity in effective population size (Ne) and effective migration rate (me), respectively. Variation in both effective demographic parameters is estimated in sliding windows via pre-computed likelihood grids. gIMble includes modules for pre-processing/filtering of genomic data and performing parametric bootstraps using coalescent simulations. To demonstrate the new approach, we analyse data from a well-studied pair of sister species of tropical butterflies with a known history of post-divergence gene flow: Heliconius melpomene and H. cydno. Our analyses uncover both large-effect barrier loci (including well-known wing-pattern genes) and a genome-wide signal of a polygenic barrier architecture.

A neurophysiological limit and its biogeographic correlations: Cold-induced spreading depolarization in tropical butterflies.

The physiology of insects is directly influenced by environmental temperature, and thermal tolerance is therefore intrinsically linked to their thermal niche and distribution. Understanding the mechanisms that limit insect thermal tolerance is crucial to predicting biogeography and range shifts. Recent studies on locusts and flies suggest that the critical thermal minimum (CTmin) follows from a loss of CNS function via a spreading depolarization. We hypothesized that other insect taxa share this phenomenon. Here we investigate whether spreading depolarization events occur in butterflies exposed to cold. Supporting our hypothesis, we find that exposure to stressful cold induced spreading depolarization in all 12 species tested. This reinforces the idea that spreading depolarization is a common mechanism underlying the insect CTmin. Furthermore, our results highlight how CNS function is tuned to match species' environments. Further research into the physiology underlying spreading depolarization will likely elucidate key mechanisms determining insect thermal tolerance and ecology.

Tropical butterflies use thermal buffering and thermal tolerance as alternative strategies to cope with temperature increase.

Climate change poses a severe threat to many taxa, with increased mean temperatures and frequency of extreme weather events predicted. Insects can respond to high temperatures using behaviour, such as angling their wings away from the sun or seeking cool local microclimates to thermoregulate or through physiological tolerance. In a butterfly community in Panama, we compared the ability of adult butterflies from 54 species to control their body temperature across a range of air temperatures (thermal buffering ability), as well as assessing the critical thermal maxima for a subset of 24 species. Thermal buffering ability and tolerance were influenced by family, wing length, and wing colour, with Pieridae, and butterflies that are large or darker in colour having the strongest thermal buffering ability, but Hesperiidae, small, and darker butterflies tolerating the highest temperatures. We identified an interaction between thermal buffering ability and physiological tolerance, where species with stronger thermal buffering abilities had lower thermal tolerance, and vice versa. This interaction implies that species with more stable body temperatures in the field may be more vulnerable to increases in ambient temperatures, for example heat waves associated with ongoing climate change. Our study demonstrates that tropical species employ diverse thermoregulatory strategies, which is also reflected in their sensitivity to temperature extremes.

Wings are not perfect: increased wing asymmetry in a tropical butterfly as a response to forest fragmentation.

Habitat fragmentation and ecosystem changes have the potential to affect animal populations in different ways. To effectively monitor these changes, biomonitoring tools have been developed and applied to detect changes in population structure and/or individual traits that reflect such changes. Fluctuating asymmetry (FA) represents random deviations from perfect symmetry in bilateral traits from perfect symmetry in response to genetic and/or environmental stresses. In this study, we evaluated the use of FA as a tool to monitor stress caused by forest fragmentation and edge formation, using the tropical butterfly M. helenor (Nymphalidae) as a model species. We collected adult butterflies from three fragments of Atlantic Forest in Brazil encompassing both edge and interior habitats. Four wing traits (wing length, wing width, ocelli area, and ocelli diameter) were evaluated. Butterflies captured at edge sites exhibited higher FA values for wing length and wing width compared to those captured at interior sites, whereas traits related to ocelli did not show differences between the two habitat types. Our results suggest that the differences in abiotic and biotic conditions between forest interior and edges can act as a source of stress, impacting the symmetry of flight-related traits. On the other hand, as ocelli are crucial for butterfly camouflage and counter-predator strategies, our results indicate that this trait may be more conserved. By employing FA, we identified trait-specific responses to habitat fragmentation, thus suggesting its potential as a biomarker for environmental stress that can be used in butterflies to monitor habitat quality and change.

Repeated genetic adaptation to altitude in two tropical butterflies

Repeated evolution can provide insight into the mechanisms that facilitate adaptation to novel or changing environments. Here we study adaptation to altitude in two tropical butterflies, Heliconius erato and H. melpomene, which have repeatedly and independently adapted to montane habitats on either side of the Andes. We sequenced 518 whole genomes from altitudinal transects and found many regions differentiated between highland (~ 1200 m) and lowland (~ 200 m) populations. We show repeated genetic differentiation across replicate populations within species, including allopatric comparisons. In contrast, there is little molecular parallelism between the two species. By sampling five close relatives, we find that a large proportion of divergent regions identified within species have arisen from standing variation and putative adaptive introgression from high-altitude specialist species. Taken together our study supports a role for both standing genetic variation and gene flow from independently adapted species in promoting parallel local adaptation to the environment.

Butterflies teach beautiful lessons about leadership

I have lived an hour away from Callaway Gardens in Georgia for over 20 years now. I've driven past the gates numerous times but never stopped. Recently I coaxed my husband into taking me to the Cecil B. Day Butterfly Center in the Gardens. The center is 7,300 square feet with over 1,000 panes of glass and state‐of‐the‐art mechanical systems. According to the center's website, it is home to more than 2,000 tropical butterflies of 50 different species, which fluctuate in diversity and density.

Butterflies teach beautiful lessons about leadership

I have lived an hour away from Callaway Gardens in Georgia for more than 20 years. I've driven past the gates numerous times, but never stopped. Recently, I coaxed my husband into taking me to the Cecil B. Day Butterfly Center in the Gardens. The center is 7,300 square feet with more than 1,000 panes of glass and state‐of‐the‐art mechanical systems. According to the Center's website, it is home to more than 2,000 tropical butterflies of 50 different species, which fluctuate in diversity and density.

Butterflies teach beautiful lessons about leadership

I have lived an hour away from Callaway Gardens in Georgia for more than 20 years. I've driven past the gates numerous times, but never stopped. Recently, I coaxed my husband into taking me to the Cecil B. Day Butterfly Center in the Gardens. The center is 7,300 square feet with more than 1,000 panes of glass and state‐of‐the‐art mechanical systems. According to the Center's website, it is home to more than 2,000 tropical butterflies of 50 different species, which fluctuate in diversity and density.

Butterflies teach beautiful lessons about leadership

I have lived an hour away from Callaway Gardens in Georgia for more than 20 years. I've driven past the gates numerous times, but never stopped. Recently, I coaxed my husband into taking me to the Cecil B. Day Butterfly Center in the Gardens. The center is 7,300 square feet with more than 1,000 panes of glass and state‐of‐the‐art mechanical systems. According to the Center's website, it is home to more than 2,000 tropical butterflies of 50 different species, which fluctuate in diversity and density.

Is elevation a strong environmental filter? Combining taxonomy, functional traits and phylogeny of butterflies in a tropical mountain

AbstractEnvironmental filters select species that tolerate and respond to habitat conditions similarly. By combining taxonomy, functional traits and phylogeny, we aimed to understand the spatial distribution of a tropical butterfly community, evaluating whether elevation acts as an environmental filter strong enough to select flight‐related traits.Frugivorous and nectarivorous butterflies were sampled with nets at seven altitudinal bands (800–1400 m) in four sampling periods. We tested seven flight‐related traits (wing length, width, and area; thorax volume; wing:thorax ratio [WTR]length, WTRwidthand WTRarea) and incorporated the effects of phylogeny in the relationships among these traits and with elevation.Butterfly diversity decreased with increased elevation, and four traits exhibited larger values at higher elevations: wing length, width, area and WTRarea.This suggests that butterflies tended to have smaller wings and robust bodies at lower elevations, and larger wings with slender bodies at higher elevations, possibly related to flight speed or wind conditions. Although the phylogenetic relatedness did not exert significant weight in the traits and elevation, we found indication of phylogenetic conservatism of wing area and WTR.Butterflies in mountains experience a strong selection by several environmental filters related to flight performance, and our study demonstrated a robust relationship between elevation, flight‐related traits and species distribution. These relationships occurred regardless of phylogenetic relatedness, but most traits are conserved and exhibit resemblance in the phylogenetic lineages of these species. These findings suggest an influence of a widespread filter promoted by the elevational gradient with convergent trait evolution.