Trait-mediated indirect interactions of ant shape on the attack of caterpillars and fruits.

Mainly owing to their high diversity and abundance, ants are formidable as predators and defenders of foliage. Consequently, ants can exclude both invertebrate and vertebrate activity on plants via direct and indirect interactions as already shown in many previous studies. Here we present empirical evidence that objects resembling ant shape on dummy caterpillars were able to repel visually oriented predators. Moreover, we also show that rubber ants on dummy fruits can repel potential fruit dispersers. Our results have direct implications on the ecological and evolutionary dynamics of interactions in ant-based systems, as ant presence could affect the fitness of its partners. In short, our study highlights the importance of visual cues in interspecific interactions and opens a new way to study the effects of ant presence to test ecological and evolutionary hypotheses.

The role of tending ants in host plant selection and egg parasitism of two facultative myrmecophilous butterflies.

Ovipositing adult females of myrmecophilous lycaenids are expected to select plants based on ant presence in order to maximize the survivorship of immature stages. Usually, larvae feed ants with honey-like solutions and, in turn, ants ward off parasitoids. Nonetheless, a rarely investigated approach is whether ant partners can also extend their protective behavior towards lycaenids eggs. Here, we investigated the ant-related oviposition pattern of Allosmaitia strophius and Rekoa marius; then, we compared egg parasitism according to the presence of ants. Lycaenid oviposition and egg parasitism (in percent) were experimentally compared in ant-present and ant-excluded treatments. The study plant, Heteropterys byrsonimifolia, is an extrafloral nectaried shrub which supports several ant species. We sampled 280 eggs, of which 39.65 % belonged to A. strophius and 60.35 % to R. marius. Both lycaenids eggs were significantly more abundant on branches with ants, especially those with Camponotus crassus and Camponotus blandus, two ant species known to attend to lycaenids. A. strophius and R. marius parasitism was 4.5- and 2.4-fold higher, respectively, in ant-present treatments, but the results were not statistically significant. Our study shows that ant-mediated host plant selection in lycaenids might be much more widespread than previously thought, and not restricted to obligate myrmecophilous species. Tending ants may be inefficient bodyguards of lycaenid eggs, because unlike larvae which release sugared liquids, eggs do not offer obvious rewards to ants. Ants can ward off parasitoids of larvae, as observed elsewhere, but our findings show that positive ant-lycaenid interactions are conditional and depend on immature ontogeny.

Two new ectoparasitic species of Aulacothrips Hood, 1952 (Thysanoptera: Heterothripidae) associated with ant-tended treehoppers (Hemiptera).

Aulacothrips Hood, 1952 is a remarkable South American genus of ectoparasitic thrips which feed on gregarious ant-tended hemipterans (Hemiptera: Auchenorrhyncha). Here we describe two new species of this genus infesting membracid treehoppers in Colombia and Brazilian Amazon, and provide a key to the five Aulacothrips spp. now recognised. Aulacothrips levinotus n. sp. is unique in having pronotum with only two pairs of major setae; and Aulacothrips tenuis n. sp. has unusually long abdominal tergite IX. These findings will be helpful for understanding the species diversification in this genus, bringing a new perspective on the diversity of Aulacothrips spp. and their myrmecophilous hemipteran hosts.

A new ant-butterfly symbiosis in the forest canopy fills an evolutionary gap.

Myrmecophilous butterflies can establish complex symbiotic relationships with ants. A caterpillar wandering among the brood of the aggressive ponerine ant Neoponera villosa was found inside the core of a nest built in the myrmecophytic bromeliad Aechmea bracteata. This is the first caterpillar found living inside a ponerine ant nest. Its DNA barcode was sequenced, and an integrative approach was used to identify it as Pseudonymphidia agave, a poorly known member of the subtribe Pachythonina in the riodinid tribe Nymphidiini. The cuticle of the tank-like caterpillar lacks projections or tubercles and is covered dorsally by specialized flat setae that form an armor of small plates. Ant-organs potentially related to caterpillar-ant signaling, such as perforated cupola organs and tentacle nectary organs, are present. These morphological traits, together with evidence of social integration (direct contact with host brood, protective morphology, slow movement, no host aggressiveness), suggest that P. agave is a symbiotic, social parasite of N. villosa, preying on its host brood. However, several knowledge gaps remain, including oviposition site, dependence on bromeliad association, steps to colony integration, and larval diet through development. Carnivory has been reported in all known members of the subtribe Pachythonina (caterpillars prey on honeydew-producing hemipterans) suggesting a shift to myrmecophagy inside the ant nests as a possible evolutionary transition.

Interaction between Mutualisms: Ant-tended butterflies exploit enemy-free space provided by ant-treehopper associations.

Although mutualisms have been intensively investigated, demonstration of indirect effects between co-occurring mutualistic systems is rare. For instance, the ecological consequences of co-occurrence of ant-tended insects on a plant have never been examined for survival effects on either trophobiont species. Here, we assess the selective pressures mediating co-occurrence of a facultative ant-tended butterfly (Parrhasius polibetes) with ant-tended treehoppers (Guayaquila xiphias) on Schefflera vinosa shrubs. We evaluated host plant selection and caterpillar survival in P. polibetes in the presence and absence of ant-treehopper associations. Paired trials revealed that butterflies preferably oviposit on branches hosting ant-tended treehoppers when they had a choice between those and branches without this interaction. Presence of ant-tended treehoppers on a branch reduced the abundance of P. polibetes' natural enemies and improved caterpillar survival in both premyrmecophylic and ant-tended phases. Thus ant-tended treehoppers create an enemy-free space on foliage that butterflies exploit to protect larval offspring. These findings connect two widely documented ant-trophobiont mutualisms and highlight the importance of considering multiple interactions for a proper understanding of ant-plant-herbivore systems. Detection of other ant-based mutualisms on oviposition to improve offspring survival may have represented an important evolutionary step in the process of host plant selection in facultative myrmecophilous butterflies.

Trade-offs underlying polyphagy in a facultative ant-tended florivorous butterfly: the role of host plant quality and enemy-free space.

The underlying mechanisms mediating the use of multiple host plants were investigated in Parrhasius polibetes (Lycaenidae), a florivorous and facultative myrmecophilous butterfly. Plant traits such as presence of ant-treehopper associations as a source of enemy-free space, flower bud dimensions, toughness, thickness, trichomes, and the corresponding performance and wear of P. polibetes mandibles were examined for three natural hosts: Schefflera vinosa (Araliaceae), Pyrostegia venusta (Bignoniaceae) and Luehea grandiflora (Malvaceae). Parasitism levels of larvae found on the three hosts were also determined. Almost all Luehea had ant-treehopper associations, and all larvae found on this host were non-parasitized. Parasitism was low in larvae found on Schefflera, half of which hosted ant-treehopper associations. No ant-treehopper association was found on Pyrostegia, where parasitism was significantly higher compared to other hosts. In the laboratory, P. polibetes performed well on Schefflera, followed by Pyrostegia. No larvae survived when fed with Luehea. Flower buds of Luehea were thicker and tougher than those of Schefflera and Pyrostegia. Indeed, mandibles of larvae reared on Luehea showed substantial wear, whereas those reared either on Schefflera or Pyrostegia presented no significant damage. Additionally, we suggest that co-occurrence with ant-treehopper associations on a plant provides parasitoid-free space for P. polibetes larvae. Our results support the hypothesis that ecological trade-offs among host plants (i.e., food quality and enemy-free space) promote polyphagy in natural populations of P. polibetes. Host morphological traits seem to play a relevant role in P. polibetes performance. To our knowledge, this is the first report showing the costs of polyphagy in a myrmecophilous butterfly.

A new species of Aricoris Westwood, 1851 (Lepidoptera: Riodinidae) from the Neotropical Cerrado savanna.

A new species of Aricoris Westwood, 1851, until now treated erroneously as Aricoris tutana (Godart, [1824]), is described and illustrated from the Neotropical Cerrado savanna. Aricoris emeryi Callaghan, Lemes Kaminski, sp. nov. can be identified by a set of characters on wings and male genitalia that differentiates it from other species belonging to the constantius group.

Immature stages of the Rubiaceae-feeding metalmark butterflies (Lepidoptera: Riodinidae), and a new function for the tentacle nectary organs.

Metalmark butterfly (Riodinidae) diversity is heavily concentrated in the Neotropical lowland forests but despite their prevalence basic information on immature stages is still scarce. Here we describe the life cycle of seven taxa in the Rubiaceae-feeding section of the Mesosemiina, including three Mesosemia Hübner, [1819], three Leucochimona Stichel, 1909, and the first information for Semomesia Westwood, 1851. Immature stage morphology of Mesosemia cippus Hewitson, 1859 is described in detail through scanning electron microscopy. Generally, eggs are laid singly and caterpillars are folivorous with a cryptic green coloration except for M. cippus which has gregarious caterpillars with a bright yellow color pattern. Immature stages of all analyzed species are morphologically similar and characterized by: oblate spheroid eggs with small spines on the rib intersections; nonmyrmecophilous larvae with sparse long setae on chalazae or pinnacles, perforated cupola organs (PCOs) and tentacle nectary organs (TNOs) in all instars; pupae attached longitudinally to the substrate by the cremaster and a silk girdle that crosses over abdominal segments A1 or A2. Functionality of the TNOs is documented for the first time in the "Mesosemia section" of the Mesosemiina, but they are not used to facilitate symbiotic interactions between caterpillars and ants. When molested, caterpillars everted the TNOs secreting a conspicuous drop of opaque and viscous liquid with a defensive function. A summary of the host plants in the "Mesosemia section" is presented, confirming the preponderance of oligophagy in the Rubiaceae. The morphological and behavioral traits here described are discussed in the context of defense against natural enemies and constitute key information to understanding the evolution of ant-organs and myrmecophily in riodinids.

Oviposition of Minstrellus grandis (Lepidoptera: Riodinidae) in a harmful ant-plant symbiosi

The oviposition behavior of the rare butterfly Minstrellus grandis (Callaghan, 1999) (Lepidoptera: Riodinidae) is recorded for the first time. Two females laid eggs on the old leaves of an unidentified Triplaris sp. (Polygonaceae), a myrmecophytic plant typically known as 'Triplaria' or 'novice' tree, inhabited by aggressive 'taxi' ants of the genus Pseudomyrmex sp. (Hymenoptera: Formicidae). These observations suggest that M. grandis caterpillars live associated with one of the most harmful types of Amazon ant-plant symbiosis. (AU)

The effect of symbiotic ant colonies on plant growth: a test using an Azteca-Cecropia system.

In studies of ant-plant mutualisms, the role that ants play in increasing the growth rates of their plant partners is potentially a key beneficial service. In the field, we measured the growth of Cecropia glaziovii saplings and compared individuals that were naturally colonized by Azteca muelleri ants with uncolonized plants in different seasons (wet and dry). We also measured light availability as well as attributes that could be influenced by the presence of Azteca colonies, such as herbivory, leaf nutrients (total nitrogen and δ(15)N), and investments in defense (total phenolics and leaf mass per area). We found that colonized plants grew faster than uncolonized plants and experienced a lower level of herbivory in both the wet and dry seasons. Colonized plants had higher nitrogen content than uncolonized plants, although the δ(15)N, light environment, total phenolics and leaf mass per area, did not differ between colonized and uncolonized plants. Since colonized and uncolonized plants did not differ in the direct defenses that we evaluated, yet herbivory was lower in colonized plants, we conclude that biotic defenses were the most effective protection against herbivores in our system. This result supports the hypothesis that protection provided by ants is an important factor promoting plant growth. Since C. glaziovii is widely distributed among a variety of forests and ecotones, and since we demonstrated a strong relationship with their ant partners, this system can be useful for comparative studies of ant-plant interactions in different habitats. Also, given this study was carried out near the transition to the subtropics, these results help generalize the geographic distribution of this mutualism and may shed light on the persistence of the interactions in the face of climate change.

Last instar larvae and pupae of Ourocnemis archytas and Anteros formosus (Lepidoptera: Riodinidae), with a summary of known host plants for the tribe Helicopini.

Last instar larvae and pupae of Ourocnemis archytas (Lepidoptera: Riodinidae) are described for the first time and compared with those of Anteros formosus, which are also described in detail. Last instars of both species present body covered with long white plumose setae, a row of orange balloon setae on the prothoracic shield, and clusters of perforated cupola organs (PCOs) near the spiracles; differences are the black cephalic capsule, the placement and format of balloon setae cluster, and the presence of enlarged black tips on some plumose setae. Pupae of O. archytas resemble that of Anteros, covered with the last instar setae and with no balloon setae. Characteristics of the immature stages of these two genera could be useful to establish the still unresolved relationship between them. A summary of the host plants of Helicopini is presented, showing a polyphagous pattern for Anteros, recorded in 21 host plant families, which contrasts with the specialized diet observed in Helicopis and Sarota. 

Immature stages of the butterfly Magneuptychia libye (L.) (Lepidoptera: Nymphalidae, Satyrinae).

The immature stages of the butterfly Magneuptychia libye (L.) are described, and their morphology is compared with other Neotropical Satyrinae.

Occurrence of Lepidopterism caused by the moth Hylesia nigricans (Berg) (Lepidoptera: Saturniidae) in Rio Grande do Sul State, Brazil.

Lepidopterism by Hylesia nigricans (Berg) moth is recorded for the first time in southern Brazil. Preventive strategies of control are proposed based on information on the biology and ecology of this moth.

Immature stages of the butterfly Magneuptychia libye (L) (Lepidoptera: Nymphalidae, Satyrinae)

The immature stages of the butterfly Magneuptychia libye (L.) are described, and their morphology is compared with other Neotropical Satyrinae.

Os estágios imaturos da borboleta Magneuptychia libye (L.) são descritos, e sua morfologia é comparada com a de outros Satyrinae Neotropicais.

Morfologia externa dos estágios imaturos de heliconíneos neotropicais: VI. Dione moneta moneta Hübner (Lepidoptera, Nymphalidae, Heliconiinae) / External morphology of the immature stages of Neotropical heliconines: VI. Dione moneta moneta Hübner (Lepidoptera, Nymphalidae, Heliconiini)

As estruturas externas do ovo, larva e pupa de Dione moneta moneta Hübner, 1825 são descritas e ilustradas, baseadas em microscopia óptica e eletrônica de varredura.

The external features of the egg, larva and pupa of Dione moneta moneta Hübner, 1825 are described and illustrated, based upon light and scanning electron microscopy.

Morfologia externa dos estágios imaturos de heliconíneos neotropicais: VII. Dryadula phaetusa (Linnaeus) (Lepidoptera, Nymphalidae, Heliconiinae) / External morphology of the immature stages of Neotropical heliconians: VII. Dryadula phaetusa (Linnaeus) (Lepidoptera, Nymphalidae, Heliconiinae)

As estruturas externas do ovo, larva e pupa de Dryadula phaetusa (Linnaeus, 1758) são descritas e ilustradas, baseadas em microscopia óptica e eletrônica de varredura.

The external features of egg, larva and pupa of Dryadula phaetusa (Linnaeus, 1758) are described and illustrated, based upon light and scanning electron microscopy.

Occurrence of Lepidopterism caused by the moth Hylesia nigricans (Berg) (Lepidoptera: Saturniidae) in Rio Grande do Sul State, Brazil

Lepidopterism by Hylesia nigricans (Berg) moth is recorded for the first time in southern Brazil. Preventive strategies of control are proposed based on information on the biology and ecology of this moth.

É registrado pela primeira vez o lepidopterismo provocado pela mariposa Hylesia nigricans (Berg) para o sul do Brasil. São apresentados alguns aspectos da biologia da espécie e relatadas medidas como estratégia preventiva de controle.