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Cyanogenic insects release cyanide and other breakdown products that are thought to make them unpalatable to predators. Cyanogenic lepidopterans such as Heliconius butterflies and Zygaena moths are rejected by vertebrate predators, but the role played by these compounds in predator deterrence is poorly explored. Here I report tests undertook with captive domestic chicks (Gallus gallus) to evaluate the effect of cyanoglucosides, linamarin and prunasin and their breakdown products. In insects as well as plants, cyanoglucosides are enzymatically broken down when the tissue is disrupted as in the case of a predator attack. The aliphatic linamarin releases cyanide and acetone upon breakdown, while prunasin is an aromatic cyanoglucoside that releases cyanide and benzaldehyde. Using concentrations that mimicked the concentration of Heliconius butterflies, I ran trials with naive chicks by offering palatable prey laced with chemicals resulting from cyanoglucoside breakdown. I categorized prey acceptance and compared the behavior of the predators towards test and control prey. Prey coated with cyanide and benzaldehyde were rejected by the birds, while acetone elicited some avoidance behavior. Intact cyanoglucosides were not rejected by the predators presumably because of fast ingestion time or lack of enzymes to break it down. Rejection of cyanide-laced prey confirms the protective nature of cyanoglucosides against a vertebrate predator. The rejection of the pungent but not toxic benzaldehyde and the potential effect of acetone suggest that cyanoglucosides could be detected via smell as well by taste. These results provide support for cyanoglucosides as defensive chemicals of aposematic lepidopterans and related arthropods.

The interdisciplinary field of Chemical Ecology in Brazil is currently composed of groups that emerged through the pioneering studies of Keith Spalding Brown Jr. and José Tércio Barbosa Ferreira. Following Keith Brown 's steps, José Roberto Trigo continued investigating the role of plant natural products in mediating the association among insects and their host plants, mainly in the Order Lepidoptera. The role of pyrrolizidine alkaloids in those associations was investigated extensively by Brown and Trigo, and most of what is currently known on this subject is based on their studies. The present work acknowledges their contribution to the Brazilian chemical ecology field and on insect-plant communication studies mediated by different chemical compounds.

Large areas in tropical countries were converted into Eucalyptus plantations for pulp production. Although these plantations are structurally more similar to native ecosystems than traditional short-lived crops, they can be less suitable for more sensitive species. Thus, it is important to know how they can harbor native biodiversity and contribute for its conservation in highly fragmented landscapes. In this work, we compared fruit-feeding butterfly assemblages from Eucalyptus plantations, forest fragments immersed in Eucalyptus plantations and samples inside a continuous forest tract on an extremely rich and threatened area of Atlantic forest in Brazil. We found that plantations harbor a less diverse assemblage of fruit-feeding butterflies, with low richness and a few, very abundant species. Samples placed in plantations were more similar to each other in species composition than those taken from fragments or continuous forests, although the dissimilarities among forest fragments are similar to those found among continuous forest samples. The occurrence of some very abundant species, mostly grass-feeding (Satyrines), differentiate the plantations from forests plots. In common between plantations and forests there were a few other species, notably some associated with second growth (Biblidinae and Satyrinae) and others with strong flying capabilities (Charaxinae). The small fragments harbored a significant portion of the regional butterfly diversity, and this reinforces the importance of actions to preserve them and to increase landscape connectivity for butterfly conservation purposes. It is clear that Eucalyptus sp. plantations cannot substitute forests for a vast majority of fruit-feeding butterflies, but it is better than other land use practices, such as pastures and sugar cane plantations, in sustaining part of this fauna and acting as a potential corridor.

The extent of biodiversity in the urban setting is related to the degree of land transformation and the relative quantity of green spaces in the city. Large tracts of green spaces may harbor species and serve as sources of colonists to other urban spaces, but the degree to which this occurs is not well known, particularly in cities in the tropics. Here we evaluate if a large urban green space (Dunas State Park) affects the diversity of fruit-feeding butterflies in city plazas. We sampled 18 plazas, varying in size (1000 to >3000 m2) and distance to the Park’s edge (up to 3000 m). In each plaza, we measured number of trees, plant cover in it and in surrounding buffers of up to 200 m. Butterflies were captured using standardized traps. We found that butterfly communities were significantly different between Park and plazas, and that individuals plazas represented a poor sample of the total butterfly diversity. Distance to the park did not influence butterfly communities in the plazas, nor did any of the local plaza characteristics. Plazas harbored mostly generalist species and experienced more fluctuations in butterfly abundance than the Park. The Park is the only significant repository of fruit-feeding butterfly biodiversity in our system. We conclude that the urban setting is a strong filter for species settlement, a worrisome conclusion for tropical cities. We offer advice on how city planners may improve this trend.

The interdisciplinary field of Chemical Ecology in Brazil is currently composed of groups that emerged through the pioneering studies of Keith Spalding Brown Jr. and Jose Tercio Barbosa Ferreira. Following Keith Brown ‘s steps, Jose Roberto Trigo continued investigating the role of plant natural products in mediating the association among insects and their host plants, mainly in the Order Lepidoptera. The role of pyrrolizidine alkaloids in those associations was investigated extensively by Brown and Trigo, and most of what is currently known on this subject is based on their studies. The present work acknowledges their contribution to the Brazilian chemical ecology field and on insect–plant communication studies mediated by different chemical compounds.

Conservation biology is designed to identify pressing environmental problems and to solve them. This review evaluates the relative effort of conservation biology in problem-based and solution-based research, and tests whether or not this has changed in the past decades for five major drivers of biodiversity loss, i.e. habitat loss and fragmentation, overexploitation, biological invasion, pollution, and climate change. By randomly sampling papers from four decades of the conservation literature (1980–2019), we estimated the frequency of solution-based research related to the five biodiversity loss drivers. We also estimated how the ratio of the words ‘problem’ and ‘solution’ has changed over time, as a proxy for discourse bias. We found that a quarter of the scientific papers on conservation constitute solution-based research, while three-quarters were classified as problem-based. Temporal analyses showed that the proportion of solution-based papers increased along the four decades, from 0.18 to 0.30, mostly due to research on effects of habitat loss and fragmentation, and overexploitation. The solution-to-problem word ratio increased steadily, from almost zero in the 1980s to 0.60 in 2019. Significant increases occurred for all drivers of biodiversity loss, indicating an important temporal change in conservation discourse and concerns. We propose that, in order to be more effective against the biodiversity crisis, conservation science should expand the solution-based agenda by active changes in graduate education, research choice, research funding priority, editorial emphasis, and media coverage that can produce desired impacts on conservation practice, public perception, and environmental policies.

Heliconiines are called passion vine butterflies because they feed exclusively on Passiflora plants during the larval stage. Many features of Passiflora and heliconiines indicate that they have radiated and speciated in association with each other, and therefore this model system was one of the first examples used to exemplify coevolution theory. Three major adaptations of Passiflora plants supported arguments in favour of their coevolution with heliconiines: unusual variation of leaf shape within the genus; the occurrence of yellow structures mimicking heliconiine eggs; and their extensive diversity of defence compounds called cyanogenic glucosides. However, the protection systems of Passiflora plants go beyond these three features. Trichomes, mimicry of pathogen infection through variegation, and production of extrafloral nectar to attract ants and other predators of their herbivores, are morphological defences reported in this plant genus. Moreover, Passiflora plants are well protected chemically, not only by cyanogenic glucosides, but also by other compounds such as alkaloids, flavonoids, saponins, tannins and phenolics. Heliconiines can synthesize cyanogenic glucosides themselves, and their ability to handle these compounds was probably one of the most crucial adaptations that allowed the ancestor of these butterflies to feed on Passiflora plants. Indeed, it has been shown that Heliconius larvae can sequester cyanogenic glucosides and alkaloids from their host plants and utilize them for their own benefit. Recently, it was discovered that Heliconius adults have highly accurate visual and chemosensory systems, and the expansion of brain structures that can process such information allows them to memorize shapes and display elaborate pre-oviposition behaviour in order to defeat visual barriers evolved by Passiflora species. Even though the heliconiine–Passiflora model system has been intensively studied, the forces driving host-plant preference in these butterflies remain unclear. New studies have shown that host-plant preference seems to be genetically controlled, but in many species there is some plasticity in this choice and preferences can even be induced. Although much knowledge regarding the coevolution of Passiflora plants and heliconiine butterflies has accumulated in recent decades, there remain many exciting unanswered questions concerning this model system.

Agroforestry systems have increased in area in tropical regions in recent decades and many studies have sought to evaluate their impact on native biodiversity. Yet, few have assessed the impact of perennial plantations such as rubber-tree harvesting on native biodiversity. The goal of our study was to assess the effect of rubber tree plantations on fruit-feeding butterflies of the endangered Brazilian Atlantic Forest in Brazil. To do so, we sampled fruit- feeding butterfly species in a landscape mosaic composed of primary forest, rubber tree plantations under two management regimes (active production with intense management and undergrowth suppression and low management plantations with no undergrowth suppression), and forest fragments immersed in rubber tree plantation matrix. By trap-baiting butterflies for a year, we captured 5800 individuals of 85 butterfly species. Species richness was higher in unmanaged (no growth suppression) plantation and forest fragments (57–60 species) and lower in managed plantation (with growth suppression) (47) and primary forest (43). Ordination analysis suggests three main community groups formed by primary forest samples, a cluster combining unmanaged plantation and fragments, and managed plantation. There was substantial variation in butterfly abundance in the landscape, but our data suggest that several forest specialists species are able to occur along the mosaic on the landscape, and despite differences in management the entire landscape can contribute for a rich biota. Loss of understory vegetation led to simplified communities, with skewed dominance of a few species. By allowing understory development, a low impact management can provide adequate habitat for native butterflies. Yet, current rubber tree plantation technology does not normally use this method, opting to use the high management approach instead. We hypothesize that these minimally benign plantations may serve as conduits for butterflies in forest patches. Thus, we suggest that rubber tree plantations near Atlantic forest fragments should encourage understory development and establish a landscape mosaic, allowing forest fragments immersed in plantation matrix to be able to exchange individuals and colonize more complex plantation habitat. Intensive suppression of undergrowth should be avoided, except for trail maintenance, and isolation of fragments in this matrix should be kept to a minimum. If undergrowth suppression cannot be avoided, then establishment of stepping stones in plantation matrix should be encouraged to reduce isolation of fragments.

Polymorphism is common in nature, but few Heliconius species are polymorphic for wing colour patterns. Eastern Brazil H. erato phyllis populations are polymorphic for hindwing elements (red raylets) and studies suggest that trait distribution varies seasonally. We carried a 3-y sampling to evaluate the hypothesis that season, wing length and pollen foraging were associated with morph diversity. Individual phenotypes were scored with regards to number of red elements in the dry and in the wet seasons. Co-mimic H. melpomene nanna was also analysed. We scored 432 H. erato and 513 H. melpomene. Our results confirm polymorphism in H. erato, with individuals showing from one to eight elements, with a mode between five and six. We found that H. melpomene is polymorphic for red dots, varying from two to five (mode = 2). Red basal dots were mostly invariant in H. erato. Even though we found a seasonal change in pollen loads, we found no association between individual phenotypes and season, pollen load scores, or wing length. We reject the hypothesis of ecological correlates of morph frequency, and suggest that trait colour variation in the two species is linked to and constrained by effects on mate recognition.

The Pectoral Antwren (Herpsilochmus pectoralis) and Caatinga Antwren (H. sellowi) are thamnophilids endemic to northeastern Brazil. The Pectoral Antwren is considered an “Endangered” species by the IUCN. The present study aimed at providing data on the distribution, abundance, habitat, and conservation status of these species in Rio Grande do Norte state (RN), Brazil, in order to help define conservation strategies for the species. Thirty-three sites in the Atlantic Forest domain were sampled between November 2005 and March 2008, for a total sampling effort of 414 h. Observations took place mainly between 5:30 h and 12:00 h, and records were based on visual and/or auditory detections. Standardized censuses were conducted in four different phytophysiognomies to determine abundance and density. Herpsilochmus pectoralis was found in 73% (n = 24) of the sampled areas, mean density was estimated at 89.1 individuals.km2 and population size was approximately 13,921 individuals for the state. Available area of occupancy was 156.25 km2. Herpsilochmus sellowi was present in 39% (n = 13) of the areas, with mean density of 60.4 individuals.km2, estimated population of 7202 and area of occupancy of 119.25 km2. The population estimate found in this study for H pectoralis is high for a small geographical area, thus demonstrate that BirdLife International information is underestimated. These data widen knowledge of the species at local and national levels, in addition to confirming the importance of H. pectoralis in RN state. The low number of protected areas in the region is alarming, given that privately-owned areas face fragmentation, selective deforesting, burnings and significant real estate development.

Heliconius butterflies are highly specialized in Passiflora, laying eggs and feeding as larvae only on these plants. Interestingly, Heliconius butterflies and Passiflora plants both contain cyanogenic glucosides (CNglcs). While feeding on specific Passiflora species, Heliconius melpomene larvae are able to sequester simple cyclopentenyl CNglcs, the most common CNglcs in this plant genus. Yet, aromatic, aliphatic, and modified CNglcs have been reported in Passiflora species and they were never tested for sequestration by heliconiine larvae. As other cyanogenic lepidopterans, H. melpomene also biosynthesize the aliphatic CNglcs linamarin and lotaustralin, and their toxicity does not rely exclusively on sequestration. Although the genes encoding the enzymes in the CNglc biosynthesis have not yet been fully biochemically characterized in butterflies, the cytochromes P450 CYP405A4, CYP405A5, CYP405A6 and CYP332A1 are hypothesized to be involved in this pathway in H. melpomene. In this study, we determine how the CNglc composition and expression of the putative P450s involved in the biosynthesis of these compounds vary at different development stages of Heliconius butterflies. We also established which kind of CNglcs H. melpomene larvae can sequestered from Passiflora. By analysing the chemical composition of the haemolymph from larvae fed with different Passiflora diets, we observed that H. melpomene is able to sequestered prunasin, an aromatic CNglcs, from P. platyloba. They were also able to sequester amygdalin, gynocardin, [C13/C14]linamarin and [C13/C14]lotaustralin painted on the plant leaves. The CNglc tetraphyllin B-sulphate from P. caerulea was not detected in the larval haemolymph, suggesting that such modified CNglcs cannot be sequestered by Heliconius. Although pupae and virgin adults contain dihydrogynocardin resulting from larval sequestration, this compound was metabolized during adulthood, and not used as nuptial gift or transferred to the offspring. Thus, we speculate that dihydrogynocardin was catabolized to recycle nitrogen and glucose, and/or to produce fitness signals during courtship and calling. Mature adults had a higher concentration of CNglcs than any other developmental stages due to intense de novo biosynthesis of linamarin and lotaustralin. All CYP405As were expressed in adults, whereas larvae mostly expressed CYP405A4. Our results shed light on the importance of CNglcs in Heliconius biology and for their coevolution with Passiflora.

Heliconius butterflies are highly specialized in Passiflora plants, laying eggs and feeding as larvae only on them. Interestingly, both Heliconius butterflies and Passiflora plants contain cyanogenic glucosides (CNglcs). While feeding on specific Passiflora species, Heliconius melpomene larvae are able to sequester simple cyclopentenyl CNglcs, the most common CNglcs in this plant genus. Yet, aromatic, aliphatic, and modified CNglcs have been reported in Passiflora species and they were never tested for sequestration by heliconiine larvae. As other cyanogenic lepidopterans, H. melpomene also biosynthesize the aliphatic CNglcs linamarin and lotaustralin, and their toxicity does not rely exclusively on sequestration. Although the genes encoding the enzymes in the CNglc biosynthesis have not yet been biochemically characterized in butterflies, the cytochromes P450 CYP405A4, CYP405A5, CYP405A6 and CYP332A1 have been hypothesized to be involved in this pathway in H. melpomene. In this study, we determine how the CNglc composition and expression of the putative P450s involved in the biosynthesis of these compounds vary at different developmental stages of Heliconius butterflies. We also establish which kind of CNglcs H. melpomene larvae can sequester from Passiflora. By analysing the chemical composition of the haemolymph from larvae fed with different Passiflora diets, we show that H. melpomene is able to sequestered prunasin, an aromatic CNglcs, from P. platyloba. They are also able to sequester amygdalin, gynocardin, [C13/C14]linamarin and [C13/C14]lotaustralin painted on the plant leaves. The CNglc tetraphyllin B-sulphate from P. caerulea is not detected in the larval haemolymph, suggesting that such modified CNglcs cannot be sequestered by Heliconius. Although pupae and virgin adults contain dihydrogynocardin resulting from larval sequestration, this compound was metabolized during adulthood, and not used as nuptial gift or transferred to the offspring. Thus, we speculate that dihydrogynocardin is catabolized to recycle nitrogen and glucose, and/or to produce fitness signals during courtship. Mature adults have a higher concentration of CNglcs than any other developmental stages due to increased de novo biosynthesis of linamarin and lotaustralin. Accordingly, all CYP405As are expressed in adults, whereas larvae mostly express CYP405A4. Our results shed light on the importance of CNglcs for Heliconius biology and their coevolution with Passiflora.

Made available in DSpace on 2019-09-12T16:53:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2018 Butterflies are one of the best-known insect groups, and they have been the subject of numerous studies in ecology and evolution, especially in the tropics. Much attention has been given to the fruit-feeding butterfly guild in biodiversity conservation studies, due to the relative ease with which taxa may be identified and specimens sampled using bait traps. However, there remain many uncertainties about the macroecological and biogeographical patterns of butterflies in tropical ecosystems. In the present study, we gathered information about fruit-feeding butterfly species in local communities from the Atlantic Forests of South America. The ATLANTIC BUTTERFLIES data set, which is part of ATLANTIC SERIES data papers, results from a compilation of 145 unpublished inventories and 64 other references, including articles, theses, and book chapters published from 1949 to 2018. In total, the data set contains 7,062 records (presence) of 279 species of fruit-feeding butterflies identified with taxonomic certainty, from 122 study locations. The Satyrini is the tribe with highest number of species (45%) and records (30%), followed by Brassolini, with 13% of species and 12.5% of records. The 10 most common species correspond to 14.2% of all records. This data set represents a major effort to compile inventories of fruit-feeding butterfly communities, filling a knowledge gap about the diversity and distribution of these butterflies in the Atlantic Forest. We hope that the present data set can provide guidelines for future studies and planning of new inventories of fruit-feeding butterflies in this biome. The information presented here also has potential use in studies across a great variety of spatial scales, from local and landscape levels to macroecological research and biogeographical research. We expect that such studies be very important for the better implementation of conservation initiatives, and for understanding the multiple ecological processes that involve fruit-feeding butterflies as biological indicators. No copyright restrictions apply to the use of this data set. Please cite this Data paper when using the current data in publications or teaching events. [dos Santos, Jessie Pereira; Lucci Freitas, Andre Victor; Brown, Keith Spalding, Jr.; Oliveira Carreira, Junia Yasmin; Gueratto, Patricia Eyng; Batista Rosa, Augusto Henrique; Lourenco, Giselle Martins; Accacio, Gustavo Mattos] Univ Estadual Campinas UNICAMP, Inst Biol, Dept Biol Anim, Campinas, SP, Brazil [Uehara-Prado, Marcio] Inst Neotrop Pesquisa Conservacao, Curitiba, Parana, Brazil [Iserhard, Cristiano Agra; Richter, Aline] Univ Fed Pelotas, Dept Ecol Zool & Genet, Campus Univ Capao Leao, Pelotas, RS, Brazil [Romanowski, Helena Piccoli; Mega, Nicolas Oliveira; Teixeira, Melissa Oliveira; Moser, Alfred] Univ Fed Rio Grande, Dept Zool, Porto Alegre, RS, Brazil [Ribeiro, Danilo Bandini; Araujo, Poliana Felix] Univ Fed Mato Grosso do Sul, Inst Biociencias, Campo Grande, Brazil [Cordeiro Filgueiras, Bruno Karol; Alves Melo, Douglas Henrique] Univ Fed Pernambuco, Dept Zool, Recife, PE, Brazil [Leal, Inara Roberta] Univ Fed Pernambuco, Dept Bot, Recife, PE, Brazil [Beirao, Marina do Vale] Univ Fed Ouro Preto, Programa Posgrad Ecol Biomas Tropicais, Ouro Preto, MG, Brazil [Ribeiro, Danilo Bandini] Univ Fed Ouro Preto, Dept Biodiversidade, Lab Ecol Evolut Insetos Dossel & Sucessao Nat, Minas Gerais, Brazil [Barbosa Cambui, Elaine Cristina] Univ Fed Bahia, PPG Multiinst Multidisciplinar Difusao Conhecimen, Salvador, BA, Brazil [Vasconcelos, Rodrigo Nogueira] Univ Estadual Feira de Santana, PPG Modelagem Ciecias Terra & Ambiente, Feira De Santana, Brazil [Cardoso, Marcio Zikan] Univ Fed Rio Grande do Norte, Dept Ecol, Natal, RN, Brazil [Paluch, Marlon] Univ Fed Reconcavo Bahia, Cruz Das Almas, BA, Brazil [Greve, Roberto Rezende] Univ Fed Integracao Latino Amer UNILA, Inst Latino Amer Ciencias Vida & Nat, Lab Ecol Metacomunidades, Foz Do Iguacu, Brazil [Voltolini, Julio Cesar] ECOTROP Grp Pesquisa & Ensino Biol Conservacao, Unitau, Dept Biol [Galetti, Mauro] Univ Estadual Sao Paulo UNESP, Inst Biociencias, Dept Ecol, Rio Claro, SP, Brazil [Regolin, Andre Luis; Sobral-Souza, Thadeu; Ribeiro, Milton Cezar] Univ Estadual Sao Paulo UNESP, Inst Biociencias, Dept Ecol, Lab Ecol Espacial Conservacao LEEC, Rio Claro, SP, Brazil

Male investment in spermatophore quality is a function of the degree of polyandry. Among butterflies and other organisms that provide gifts, polyandry tends to select for gifts of better quality than monandry. Tropical butterfly species Heliconius erato and H. melpomene differ in mating systems and provide an ideal system to test expectations regarding allocation to spermatophore quality and production. Heliconius erato males mate with females while they emerge from pupa. Females mate for life and show no mate choice. In H. melpomene, females are courted by males and may mate several times in their lifetime. In order to evaluate whether spermatophore quality (mass and protein content) differed between the two species we conducted mating experiments with virgin males and virgin females in an outdoor insectary. In order to study the dynamics of spermatophore production during subsequent matings, males were also allowed to mate two or more times. Spermatophores of virgin H. melpomene males contained significantly more protein than those of H. erato, confirming theoretical expectations; spermatophore mass was not different. The polyandrous species also showed a significant reduction in mass and protein content in the second mating, while H. erato responses were mixed but non significant. Additionally, the effect of time between successive matings was dependent on species identity. Our results confirm that polyandrous Heliconius invest more in spermatophore quality than its monandrous congener. Two explanations are suggested for the observed loss of mass and protein content in polyandrous Heliconius, potential cost for production or strategic ejaculation.

Heliconius nattereri C. Felder & R. Felder, 1865 is an enigmatic and rarely collected species. Because of severe habitat reduction, the species is currently listed as endangered. We here report the confirmation of a northernmost population. This collection and further observations reported here add two more known localites to the distribution of the species. Two of the three confirmed locations are in protected areas. We worry that the northern population may be at great risk because it is not formally protected. We urge conservation efforts to preserve the local forests where the species is found.

Eucalyptus plantations are increasing in Brazil, frequently replacing pastures, but there is still scarce information about its capacity to maintain the fauna of neighbor forest remnants. In this study, we compared descriptors of the communities of leaf litter organisms (lizards, anurans, myriapods, arachnids, orthopterans, coleopterans, and ants) between a large remnant of primary Atlantic Forest and an adjacent eucalyptus monoculture (phase 1). Then, we compared the same descriptors for leaf litter lizards and anurans, Euglossini bees, and frugivorous butterflies among the largest remnant, small remnants at intermediate regeneration stage, and eucalyptus monocultures that were not adjacent to the largest remnant (phase 2). Monocultures were sampled immediately before logging. In phase 1, we detected significant differences in structure between the forest and the monoculture in six out of seven communities sampled. Ca. 81% of the species of the landscape were recorded in the forest, but only 54% of these were found also in the monoculture. In phase 2, the structure of two out of four forest communities was significantly different from the structure of small remnants and monocultures. On average, 76% of the species found in the whole landscape were sampled in the forest. Out of this subset, on average 74% of the species were also sampled in small remnants and 68% in monocultures. Findings of the present study point out a moderate capacity of eucalyptus monocultures to harbor species of the forest fauna even when fully grown but highlights the opportunity that they might offer for increasing connectivity in anthropogenic forest landscapes depending on their management

Nestedness is a useful metric that characterizes the generalist–specialist balance in ecological communities. Although several nestedness indices have been proposed, few have explored how species abundance per se affects their performance and the ability to detect true interaction networks. We here develop a mathematical framework that takes into account abundance in estimates of nestedness. We use an analytical approach to relate abundance and nestedness. In our null model the probability of interaction among species is determined solely as function of their abundances. Assuming a power-law abundance model we analytically find the nestedness index and its coefficient of variability. We find that the sloping abundance distribution of our null model generates more nested structures. On the other hand steeper abundances lead to higher coefficients of variability. Both results suggest that nestedness analysis should be evaluated and explanations sought carefully.

While butterfly responses to climate change are well studied, detailed analyses of the seasonal dynamics of range expansion are few. Therefore, the seasonal range expansion of the butterfly Heliconius charithonia L. (Lepidoptera: Nymphalidae) was analyzed using a database of sightings and collection records dating from 1884 to 1992 from Texas. First and last sightings for each year were noted, and residency time calculated, for each collection locality. To test whether sighting dates were a consequence of distance from source (defined as the southernmost location of permanent residence), the distance between source and other locations was calculated. Additionally, consistent directional change over time of arrival dates was tested in a well-sampled area (San Antonio). Also, correlations between temperature, rainfall, and butterfly distribution were tested to determine whether butterfly sightings were influenced by climate. Both arrival date and residency interval were influenced by distance from source: butterflies arrived later and residency time was shorter at more distant locations. Butterfly occurrence was correlated with temperature but not rainfall. Residency time was also correlated with temperature but not rainfall. Since temperature follows a north-south gradient this may explain the inverse relationship between residency and distance from entry point. No long-term directional change in arrival dates was found in San Antonio. The biological meaning of these findings is discussed suggesting that naturalist notes can be a useful tool in reconstructing spatial dynamics.

Theory predicts that when males provision females with nuptial gifts that include nutrients, the degree of polyandry should be positively correlated with the size or quality of the gift. This is because larger and more nutritious gifts tend to increase female refractory period, reducing the chances the female will remate soon. This decreases the likelihood of sperm competiton and consequently increases the donor male fitness. Butterflies in the genus Heliconius Kluk (Lepidoptera: Nymphalidae: Heliconini) exhibit variable mating systems that include monandry and polyandry. In addition to protein in the spermatophore, males increase gift quality by providing females with cyanide, which may contribute to protection of the female or her eggs. We tested whether degree of polyandry and gift quality (spermatophore weight and cyanide content) were correlated in nine Heliconius species from greenhouse populations. As predicted, both spermatophore weight and cyanide content were correlated with mating frequency. This is the first report to show that degree of polyandry correlates with allocation of defensive chemical as part of a nuptial gift.

Trichomes reduce herbivore attack on plants by physically and/or chemically inhibiting movement or other activities. Despite evidence that herbivores are negatively affected by trichomes there also reports of insect counter-adaptations that circumvent the plant’s defense. This paper reports on a study that investigated the likely mechanisms employed by larvae of the nymphalid butterfly, Heliconius charithonia (L.), that allow it to feed on a host that is presumably protected by hooked trichomes (Passiflora lobata (Killip) Hutch). Evidence were gathered using data from direct observations of larval movement and behavior, faeces analysis, scanning electron microscopy of plant surface and experimental analysis of larval movement on plants with and without trichomes (manually removed). The latter involved a comparison with a non specialist congener, Heliconius pachinus Salvin. Observations showed that H. charithonia larvae are capable of freeing themselves from entrapment on trichome tips by physical force. Moreover, wandering larvae lay silk mats on the trichomes and remove their tips by biting. In fact, trichome tips were found in the faeces. Experimental removal of trichomes aided in the movement of the non specialist but had no noticeable effect on the specialist larvae. These results support the suggestion that trichomes are capable of deterring a non specialist herbivore (H. pachinus). The precise mechanisms that allow the success of H. charithonia are not known, but I suggest that a blend of behavioral as well as physical resistance mechanisms is involved. Future studies should ascertain whether larval integument provides physical resistance to trichomes.

Males of several insect species transfer nuptial gifts to females during mating, typically in the form of a protein-rich spermatophore. In chemically defended species, males could potentially enhance such a gift with chemicals that help protect the female, her eggs, or both. This was shown for lepidopteran species that accumulate pyrrolizidine alkaloids. Most Heliconius butterflies are presumably protected from predators by virtue of de novo synthesized and/or sequestered cyanogenic glycosides. Males of Heliconius species are known to transfer nutritional gifts to the females but whether defensive chemicals could also be transferred is not known. To ascertain whether transfer of cyanogens occurs, we dissected freshly mated females from nine different Heliconius species and analyzed spermatophores for cyanogenic glycosides. We found cyanogens in the spermatophores of all nine species. This is the first time cyanogenic glycosides are reported in the spermatophores of arthropods. We discuss the implications of these findings for Heliconius biology and for other cyanogenic insects as well. We suggest that chemically defended species commonly lace their nuptial gifts with defensive chemicals to improve gift quality.

Most butterfly species forage for nectar, which provides them with carbohydrates and to some degree other nutrients, such as lipids and amino acids (Boggs 1987). A small number of genera feed exclusively on rotting fruits and plant sap (DeVries et al. 1999). Some 40 passion vine butterfly species, belonging to the genus Heliconius Kluk and a closely related monospecific genus Laparus Billberg gather nutrients from pollen feeding (Brown 1981, Gilbert 1972). Although common in bees, wasps, flies and beetles (Roulston & Cane 2000, Thorpe 2000), pollen feeding is rare among lepidopterans. In order to collect pollen, adults scrape anthers with the proboscis and gather the grains. The pollen is then incubated in solution and the amino acid-rich solution is ingested. The empty pollen grains are eventually discarded (Gilbert 1972, Krenn & Penz 1998). Pollen feeding provides amino acids that are used for egg production and somatic maintenance in adult Heliconius (Dunlap-Pianka 1979, Gilbert 1972, 1991). The most common sources of pollen are flowers of species in the genera Psiguria Neck. ex Arn. and Gurania (Schltdl.) Cogn. (Cucurbitaceae). The home range of an individual Heliconius will encompass one to many pollen plants (Murawski & Gilbert 1986).

We provide description of eggs and nest structure for two Brazilian antwrens, including the IUCN "vulnerable" species, H. pectoralis Sclater, 1857, and the BirdLife International "near-threatened", H. sellowi Whitney & Pacheco, 2000. Our observations derive from a larger study on Herpsilochmus Cabanis, 1847 distribution in coastal forest fragments in the northern range limit of the Brazilian Atlantic rainforest. Both species nested in relatively open forest. The nest of H. sellowi was built with fungal hyphae, a trait common among some birds. Both eggs were moderately beige with brown spots. Most of the information on Brazilian antwren nesting comes from species that do not occur in the Atlantic rainforest. This is the first account for nest behavior for Atlantic rainforest antwrens. Descrevemos a estrutura do ninho e características dos ovos de duas espécies brasileiras de Herpsilochmus, incluindo a espécie vulnerável (IUCN) H. pectoralis Sclater, 1857 e a quase ameaçada (BirdLife International) H. sellowi Whitney & Pacheco, 2000. Nossas observações derivam de um estudo maior sobre a distribuição de Herpsilochmus Cabanis, 1847 em fragmentos costeiros de Mata Atlântica em seu limite norte. Ambas as espécies nidificam em floresta relativamente aberta. O ninho de H. sellowi foi construído com hifas de fungo (Marasmius), uma característica comum entre algumas aves. Os ovos das duas espécies foram moderadamente beges, com pequenas manchas marrons. A maioria das informações disponíveis sobre nidificação do gênero no Brasil provem de espécies que vivem fora da Mata Atlântica. Este é o primeiro relato do comportamento de nidificação para Herpsilochmus na Mata Atlântica.

Pyrrolizidine alkaloids are considered the primary defence mechanism in aposematic ithomiine butterflies and arctiid moths. Despite evidence that pyrrolizidine alkaloids are effective against some invertebrate predators, proof for a protective function of pyrrolizidine alkaloids against vertebrate predators is fragmented. The present work shows that the pyrrolizidine alkaloid monocrot-aline is unpalatable to the pileated finch, Coryphospingus pileatusand that the unpalatability is learned through association with a specific colour pattern (blue stripes). In a series of trials, using mealworms as model prey, birds rejected those to which pyrrolizidine alkaloid solution had been applied topically but accepted prey devoid of the alkaloid. Subsequent offerings of prey with pyrrolizidine alkaloid and a painted blue-striped pattern led to consistent rejections by the experimental birds. Birds were then offered blue-striped painted larvae without pyrrolizidine alkaloids ('mimics'), which were rejected at levels similar to the previous trial. The predators learned to recognize the prey as unpalatable items based on their experience in the previous encounters. These results provide evidence for the protective capacity of the pyrrolizidine alkaloid against a vertebrate predator and supports the role of these chemicals in aposematism in the Lepidoptera.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour

Mimicry among Heliconius butterflies provides a classic example of coevolution but unresolved relationships among mimetic subspecies have prevented examination of codiversification between species. We present amplified fragment length polymorphism and mtDNA datasets for the major comimetic races of Heliconius erato and H. melpomene . The AFLP data reveal unprecedented resolution, clustering samples by geography and race in both species. Our results show that, although H. erato and H. melpomene co-occur, mimic each other, and exhibit parallel shifts in color pattern, they experienced very different modes of diversification and geographic histories. Our results suggest that H. erato originated on the western side of South America whereas H. melpomene originated in the east. H. erato underwent rapid diversification and expansion with continued gene-flow following diversification, resulting in widely dispersed sister taxa. In contrast, H. melpomene underwent a slower pace of diversification with lower levels of gene flow, producing a stepwise directional expansion from west to east. Our results also suggest that each of the three main wing pattern phenotypes originated and/or was lost multiple times in each species. The rayed pattern is likely to be the ancestral phenotype in H. erato whereas postman or red patch is likely to be ancestral in H. melpomene . Finally, H. cydno and H. himera are monophyletic entities clearly nested within H. melpomene and H. erato , rather than being their respective sister species. Estimates of mtDNA divergence suggest a minimum age of 2.8 and 2.1 My for H. erato and H. melpomene , respectively, placing their origins in the late Pliocene.

New occurrences for two Heliconius Kluk species are reported for sites in inland Bahia, Brazil. New inland sites are reported for Heliconius sara (Fabricius), a species normally found at coastal regions. To our knowledge, Heliconius besckei Ménétriés, a species restricted to cool mountain habitats, is reported for Northeastern Brazil for the first time. Novas ocorrências para duas espécies de Heliconius Kluk são registradas para áreas no interior da Bahia. Novas áreas interioranas para Heliconius sara (Fabricius), uma espécie encontrada na costa, são apresentadas. Este é, provavelmente, o primeiro relato de Heliconius besckei Ménétriés para o Nordeste brasileiro.

BackgroundBrazil's Atlantic Forest is a biodiversity hotspot endangered by severe habitat degradation and fragmentation. Habitat fragmentation is expected to reduce dispersal among habitat patches resulting in increased genetic differentiation among populations. Here we examined genetic diversity and differentiation among populations of twoHeliconiusbutterfly species in the northern portion of Brazil's Atlantic Forest to estimate the potential impact of habitat fragmentation on population connectivity in butterflies with home-range behavior.ResultsWe generated microsatellite, AFLP and mtDNA sequence data for 136Heliconius eratospecimens from eight collecting locations and 146H. melpomenespecimens from seven locations. Population genetic analyses of the data revealed high levels of genetic diversity inH. eratorelative toH. melpomene, widespread genetic differentiation among populations of both species, and no evidence for isolation-by-distance.ConclusionsThese results are consistent with the hypothesis that the extensive habitat fragmentation along Brazil's Atlantic Forest has reduced dispersal ofHeliconiusbutterflies among neighboring habitat patches. The results also lend support to the observation that fine-scale population genetic structure may be common inHeliconius. If such population structure also exists independent of human activity, and has been common over the evolutionary history ofHeliconiusbutterflies, it may have contributed to the evolution of wing pattern diversity in the genus.

As abundâncias e identidades das espécies de qualquer comunidade biológica mudam tanto ao longo do espaço quanto do tempo. Não obstante, aspectos espaciais da biodiversidade têm sido muito mais explorados do que os temporais. Um dos motivos pelos quais padrões temporais têm recebido menos atenção é a escassez de estudos de longo prazo, especialmente na região neotropical, uma das mais biodiversas e ameaçadas do planeta. Estudar a dinâmica de populações e comunidades ao longo do tempo pode revelar processos ecológicos fundamentais, bem como descrever como pressões naturais e humanas afetam a biodiversidade. Entender a dinâmica das populações e comunidades envolve entender as histórias de vida dos organismos, como eles interagem com o ambiente, o papel de interações entre espécies, o papel de processos demográficos estocásticos, dentre outros fatores. Nesta tese investigamos a dinâmica temporal de populações e comunidades de borboletas e aves, e ao longo dos capítulos avaliamos o papel de diferentes processos na regulação dessas dinâmicas. No Capítulo 1 investigamos se um comportamento sazonal observado em borboletas Ithomiini (Nymphalidae, Danainae), supostamente adaptativo à seca - os \"bolsões de Ithomiini\"- seria uma simples resposta reativa à falta de chuvas ou se mecanismos endógenos (\"relógios biológicos\") estariam envolvidos. No Capítulo 2 realizamos um estudo de dinâmica populacional comparada de borboletas miméticas da tribo Ithomiini. Algumas evidências têm sugerido que além de convergir na morfologia, espécies co-miméticas tenderiam a convergir também no comportamento, no uso de microhabitats e possivelmente em suas dinâmicas populacionais. Testamos as hipóteses de que 1) pares de espécies co-miméticas (i.e., com a morfologia convergente) ou 2) pares de espécies mais próximas filogeneticamente teriam suas dinâmicas populacionais mais correlacionadas do que pares de espécies agrupados ao acaso. No Capítulo 3 descrevemos como a composição de espécies de assembleias de aves e borboletas de nove localidades tropicais e subtropicais na América do Sul e do Norte variou ao longo do tempo (anos a décadas), e se diferenças demográficas entre espécies (nicho) seriam importantes para explicar os padrões observados. No Capítulo 1 encontramos evidências de que a agregações seriam um comportamento endógeno sincronizado com o fotoperíodo, com plasticidade limitada para lidar com as alterações no regime de chuvas previstas para a região e para o continente. No Capítulo 2 encontramos que as dinâmicas populacionais de pares de espécies de Ithomiini de um mesmo anel mimético ou mais próximas filogeneticamente não tenderam a ser mais correlacionadas do que pares reunidos ao acaso, e que as espécies, anéis miméticos e subtribos estudadas tiveram suas dinâmicas temporais mais correlacionados do que seria esperado por acaso. Estes resultados e os do Capítulo 1 sugerem que na dinâmica desse sistema as pressões seletivas exercidas por fatores ambientais seriam mais importantes do que interações entre espécies. No Capítulo 3 mostramos que a composição de espécies de assembleias de aves na Amazônia, Cerrado, Mata Atlântica e Flórida se alterou ao longo dos anos, mesmo em assembleias de áreas bem preservadas. Sobreposta a essa rotatividade (turnover) interanual também encontramos rotatividade sazonal, previsível, na composição de espécies de assembleias de aves da Amazônia e da Mata Atlântica e na assembleia de borboletas Ithomiini. Padrões de rotatividade sazonal na composição de espécies podem ser mais comuns em comunidades neotropicais do que se imagina. As estratégias temporais dos organismos neotropicais, as quais parecem ser a base dos padrões sazonais observados nas comunidades, podem ser largamente determinadas por ritmos (\"relógios\") endógenos. Estudos sobre a regulação dos ritmos e estratégias temporais dos organismos, e dos efeitos das mudanças climáticas e do uso do solo sobre eles, são essenciais. Um importante passo nesse sentido é a disseminação de estudos de longo-prazo de populações e comunidades, contínuos, sistemáticos e com resolução para detectar padrões sazonais. Além disso, a interação das perspectivas, bases teóricas e abordagens da biologia molecular, fisiologia, cronobiologia e ecologia pode avançar nosso entendimento sobre os processos que moldam a dinâmica da biodiversidade e sobre as consequências das perturbações humanas sobre os ecossistemas The species abundances and identities of any biological community change both over space and time. Nevertheless, Spatial biodiversity dimensions have been much more exploited than temporal ones. One of the reasons for which temporal patterns have received less attention is a scarcity of long-term studies, especially in the neotropical region, one of the most biodiverse and endangered on the planet. Studying the dynamics of populations and communities over time can reveal key ecological processes as well as describe how natural and human pressures affect biodiversity. Understanding the dynamics of populations and communities involves understanding organisms life histories, how they interact with the environment, the role of interactions among species, the role of stochastic demographic processes, and other factors. In this dissertation we investigated the temporal dynamics of butterflies and birds populations and assemblages, and throughout its chapters we evaluate the role of different processes in the regulation of dynamics. In Chapter 1 we investigated whether a seasonal behavior observed in butterflies Ithomiini (Nymphalidae, Danainae), supposedly adaptive to dissecation - the \"Ithomiini pockets \" - is a simple reactive response to drought or there is internal time-keeping mechanisms involved. In Chapter 2, we performed a comparative population dynamics study of mimetic butterflies of the Ithomiini tribe. Some evidence has suggested that besides the convergence in morphology, co-mimetic species would tend to converge also in behavior, in the use of microhabitats and possibly in their population dynamics. We hypothesized that (1) pairs of co-mimetic species or (2) pairs of species more phylogenetically related would have their population dynamics more correlated than pairs of species grouped at random. In Chapter 3 we described how species composition of bird and butterfly assemblages from nine tropical and subtropical locations in South and North America varied over time (years and decades), and if demographic differences between species (niche) are needed to explain observed patterns. In Chapter 1 we found evidence that Ithomiini pockets are regulated by internal time-keeping mechanisms synchronized to photoperiod, and that mechanism has limited plasticity to cope with rainfall regime changes predicted for the study region and for the continent as a whole. In Chapter 2 we found that the population dynamics of Ithomiini species pairs more phylogenetically related or belonging to the same mimetic ring did not tend to be more correlated than pairs assembled at random, and that the species, mimetic rings and subtribes had their temporal dynamics more correlated than would be expected By chance These results and those of Chapter 1 suggest that this system dynamics is more influenced by selective pressures exerted by environmental factors than by species interactions. In Chapter 3 we show that the composition of bird assemblages in the Amazon, Cerrado, Atlantic Rainforest, and Florida has changed over the years, even in assemblies of well-preserved areas. Superimposed to this interannual turnover we also found seasonal, predictable turnover in species composition of bird assemblages of the Amazon and Atlantic Forest and in the Ithomiini butterflies assembly. Patterns of seasonal turnover in species composition may be more common in neotropical communities than is imagined. The temporal strategies of neotropical organisms, which appear to be the basis of the seasonal patterns observed in communities, can be largely determined by endogenous rhythms (\"biological clocks\"). Studies on the regulation of organisms\' temporal rhythms and strategies, and the effects of climate change and land use on them, are essential. An important step in this direction is the dissemination of continuous, systematic, population and community long-term studies, with sampling resolution to detect seasonal patterns. In addition, the interaction of perspectives, theoretical basis, and approaches of molecular biology, physiology, chronobiology, and ecology can advance our understanding of the processes that shape biodiversity dynamics and the consequences of human disturbances on ecosystems