The global distribution of diet breadth in insect herbivores.

Understanding variation in resource specialization is important for progress on issues that include coevolution, community assembly, ecosystem processes, and the latitudinal gradient of species richness. Herbivorous insects are useful models for studying resource specialization, and the interaction between plants and herbivorous insects is one of the most common and consequential ecological associations on the planet. However, uncertainty persists regarding fundamental features of herbivore diet breadth, including its relationship to latitude and plant species richness. Here, we use a global dataset to investigate host range for over 7,500 insect herbivore species covering a wide taxonomic breadth and interacting with more than 2,000 species of plants in 165 families. We ask whether relatively specialized and generalized herbivores represent a dichotomy rather than a continuum from few to many host families and species attacked and whether diet breadth changes with increasing plant species richness toward the tropics. Across geographic regions and taxonomic subsets of the data, we find that the distribution of diet breadth is fit well by a discrete, truncated Pareto power law characterized by the predominance of specialized herbivores and a long, thin tail of more generalized species. Both the taxonomic and phylogenetic distributions of diet breadth shift globally with latitude, consistent with a higher frequency of specialized insects in tropical regions. We also find that more diverse lineages of plants support assemblages of relatively more specialized herbivores and that the global distribution of plant diversity contributes to but does not fully explain the latitudinal gradient in insect herbivore specialization.

South American spider mites: new hosts and localities.

In order to contribute to taxonomic information on Tetranychid mites (Acari: Tetranychidae) in South America, surveys were conducted in Brazil (15 States and the Federal District) and Uruguay (one Department); 550 samples of 120 plant species were collected. Tetranychid mite infestations were confirmed in 204 samples, and 22 species belonging to seven genera of the Bryobiinae and Tetranychinae subfamilies were identified on 58 different host plants. Thirty-six new plant hosts were found in Brazil, South America, and worldwide for the following species: Eutetranychus banksi (McGregor); Mononychellus tanajoa (Bondar); Oligonychus anonae Paschoal; O. mangiferus (Rahman and Sapra); Tetranychus bastosi Tuttle, Baker and Sales; T. desertorum Banks, 1900 , T. evansi Baker and Pritchard; T. ludeni Zacher; T. mexicanus (McGregor); T. neocaledonicus André; and T. urticae Koch. Four new localities in Brazil were reported for Eotetranychus tremae De Leon; O. anonae; Panonychus ulmi (Koch); and T. gloveri Baker and Pritchard.

A critical review on some closely related species of Tetranychus sensu stricto (Acari: Tetranychidae) in the public DNA sequences databases.

Taxonomic misidentification of the specimens used to obtain DNA sequences is a growing problem reported for different groups of organisms, which threatens the utility of the deposited sequences in public DNA databases. This paper provides new evidence of misidentifications in molecular DNA public databases in phytophagous mites of the Tetranychidae family belonging to the group Tetranychus (Tetranychus). Several species in this group are of economic and quarantine importance in agriculture and among them Tetranychus urticae, a highly polyphagous mite causing outbreaks in many crops worldwide, is certainly the most studied. We analyzed and evaluated the identity of 105 GenBank accessions of ITS2 rDNA and 138 COI mtDNA sequences which were deposited as T. urticae and those of 14 other taxa morphologically closely related to Tetranychus sensu stricto. In addition, ITS2 and COI sequences of 18 T. urticae samples collected for this study and identified by morphological criteria, were generated and included in the analyzed dataset. Among the deposited sequences in the GenBank database, numerous cases of apparently mistaken identities were identified in the group Tetranychus s. str., especially between T. urticae, T. cinnabarinus, T. kanzawai and T. truncatus. Unreliable sequences (misidentified or dubious) were estimated at nearly 30%. In particular the analysis supports the invalidity of the controversial species status of T. cinnabarinus. More generally, it highlights the need of using combined morphological and molecular approaches to guarantee solid species diagnostics for reliable sequence accessions in public databases.

Changing interactions among persistent species as the major driver of seasonal turnover in plant-caterpillar interactions.

ß diversity of herbivorous insects in the tropics is usually very high, and there is often strong dissimilarity in herbivore species composition across different spatial scales and different abiotic gradients. Similarly, turnover is high for trophic interactions between herbivorous insects and their host plants. Two factors have been proposed to explain temporal or spatial differences in trophic interactions: changes in species composition and temporal changes in the behavior of shared species. The goal of this study was to evaluate determinants of high ß diversity of trophic interactions between lepidopteran caterpillars and their host plants across dry and rainy seasons and their transitions. Over the course of a year, interaction diversity data were collected from 275 temporary plots in Cerrado vegetation, comprising 257 species of caterpillars, 137 species of host plants and 503 different trophic interactions. All these diversity parameters varied across seasons. Species assemblages of caterpillars and plants were different among the four seasons, and there was a high turnover of interactions between the seasons. The high temporal ß diversity of trophic interactions was mostly due to interaction rewiring between co-occurring species, as opposed to changes in species composition over time.

Temporal occurrence of two morpho butterflies (Lepidoptera: Nymphalidae): influence of weather and food resources.

The seasonality of fruit-feeding butterflies is very well known. However, few studies have analyzed the influence of climatic variables and resource availability on the temporal distributions of butterflies. Morpho helenor achillides (C. Felder and R. Felder 1867) and Morpho menelaus coeruleus (Perry 1810) (Nymphalidae) were used as models to investigate the influences of climatic factors and food resources on the temporal distribution of these Morphinae butterflies. These butterflies were collected weekly from January 2005 to December 2006 in the Parque Nacional de Brasília (PNB). In total, 408 individuals were collected, including 274 of M. helenor and 134 of M. menelaus. The relative abundance of the two species was similar in 2005 (n = 220) and 2006 (n = 188). Of the variables considered, only the relative humidity and resource availability measured in terms of phenology of zoochorous fruits of herbaceous plants explained a large proportion of the variation in the abundance of these butterflies. Both of the explanatory variables were positively associated with the total abundance of individuals and with the abundances of M. helenor and M. menelaus considered separately. The phenology of anemochorous fruits was negatively associated with butterfly abundance. The temporal distribution of the butterflies was better predicted by the phenology of the zoochorous fruits of herbaceous plants than by the climatic predictors.

Elbella luteizona (Mabille, 1877) (Lepidoptera, Hesperiidae: Pyrginae) in Brazilian Cerrado: larval morphology, diet, and shelter architecture

Abstract This study examined temporal variation in the abundance of immature stages of Elbella luteizona (Hesperiidae) and describes the morphology and behavior of the larvae on their host plants, Byrsonima coccolobifolia and Myrsine guianensis. Five hundred sixty-eight 10 m diameter plots were searched for caterpillars in the Brazilian Cerrado over a period of one year. We inspected 5968 host plants, and found 31 eggs and 262 larvae on 244 plants. Similar numbers of immatures were found in both species of host plants. The abundance of immature stages varied monthly and was significantly higher in the dry season on both host plants, which may be due to the low density of natural enemies during that time. E. luteizona is univoltine, and larvae present relatively little morphological variation. However, during development, substantial changes occur in the architecture of leaf shelters that caterpillars construct. In addition, E. luteizona larvae develop very slowly, taking more than 300 days to complete metamorphosis.

Alternative food sources and overwintering feeding behavior of the boll weevil, Anthonomus grandis boheman (Coleoptera: Curculionidae) under the tropical conditions of Central Brazil.

The boll weevil causes serious damage to the cotton crop in South America. Several studies have been published on this pest, but its phenology and behavior under the tropical conditions prevailing in Brazil are not well-known. In this study the feeding behavior and main food sources of adult boll weevils throughout the year in Central Brazil was investigated. The digestive tract contents of insects captured in pheromone traps in two cotton fields and two areas of native vegetation (gallery forest and cerrado sensu stricto) were analyzed. The insect was captured all through the year only in the cerrado. It fed on pollen of 19 different plant families, on Pteridophyta and fungi spores and algae cysts. Simpson Index test showed that the cerrado provided greater diversity of pollen sources. In the beginning of the cotton cycle, the plant families used for pollen feeding were varied: in cotton area 1, the weevil fed on Poaceae(50%), Malvaceae and Smilacaceae (25% each); in cotton area 2 the pollen sources were Malvaceae (50%), Asteraceae (25%) and Fabaceae and Clusiaceae (25% each); in the cerrado they were Chenopodiaceae (67%) and Scheuchzeriaceae (33%). No weevils were collected in the gallery forest in this period. After cotton was harvested, the family Smilacaceae was predominant among the food plants exploited in all the study areas. These results help to explain the survivorship of adult boll weevil during cotton fallow season in Central Brazil and they are discussed in the context of behavioral adaptations to the prevailing tropical environmental conditions.

Biology and occurrence of Inga Busk species (Lepidoptera: Oecophoridae) on Cerrado host plants.

We sampled Inga Busk species caterpillars weekly in the cerrado on 15 plants of Diospyros burchellii Hern. (Ebenaceae) from January 2002 to December 2003, on 30 plants of Caryocar brasiliense (Caryocaraceae) from July 2003 to June 2004, and since 1991 on several other plant species. In total we found 15 species of Inga on cerrado host plants. Nine species were very rare, with only one to five adults reared. The other six species occurred throughout the year, with higher abundance during the dry season, from May to July, coinciding with overall peaks of caterpillar abundance in the cerrado. Caterpillars of the genus Inga build shelters by tying and lining two mature or old leaves with silk and frass, where they rest and develop (a common habit found in Oecophorinae). The final instar builds a special envelope inside the leaf shelter, where it will complete the larval stage and pupate. The species are very difficult to distinguish in the immature stages. External features were useful in identifying only four species: I. haemataula (Meyrick), I. phaecrossa (Meyrick), I. ancorata (Walsingham), and I. corystes (Meyrick). These four species are polyphagous and have wide geographical distributions. In this paper we provide information on the natural history and host plants of six Inga species common on cerrado host plants, for which there are no reports in the literature.

Temporal and spatial variation of Stenoma cathosiota Meyrick (Lepidoptera: Elachistidae) caterpillar abundance in the cerrado of Brasilia, Brazil.

The caterpillars of Stenoma cathosiota Meyrick feed on Roupala montana Aubl. (Proteaceae) in the cerrado of the Distrito Federal, Brazil. They construct shelters by joining leaves of the plant where they feed and pupate. The caterpillars are parasitized by a wasp (Hymenoptera: Brachonidae), which emerges from the pupae. Caterpillar abundance and parasitism frequency were associated in an area of frequently burned cerrado (biennial fire) and in another area that burns sporadically (1987 and 1994). For S. cathosiota, the variation among years in a single area, with sporadic fires, was greater than the variation among areas with different fire regimes. Caterpillar abundance among years was significantly different in the area that burns sporadically (chi2 = 24.06; df. = 1; P = 0.000). However, there were no significant differences on caterpillar abundance between areas for the same period (chi2 = 3.45; df. = 1; P = 0.063). Parasitism frequency was high, reaching 29% of the collected caterpillars, and did not differ among areas. The great temporal variation in abundance of lepidopteran caterpillars in the cerrado makes it difficult to determine the effects that fire exerts over this fauna.

[Folivore caterpillars on Roupala montana Aubl. (Proteaceae) in cerrado sensu stricto]. / Lepidópteros folívoros em Roupala montana Aubl. (Proteaceae) no cerrado sensu stricto.

Richness of lepidopteran species in the cerrado is high. The confirmation of this richness is based on adult records but knowledge of larvae-host plants interactions is still incipient. The main purpose of this work was to identify folivorous caterpillar species on Roupala montana Aubl. in areas of a Brazilian cerrado sensu stricto, their dietary range, and the relative age of the consumed leaves richness. Three data sets, collected from 1991 to 2004 were used in this study. All caterpillars found on the host plants in the field were collected and reared in the laboratory. Sixty-two lepidopteran species from 22 families were recorded; they were found feeding on new (8%) and mature (92%) leaves of R. montana. Cerconota sciaphilina (Zeller) (Elachistidae), two unidentified Gracillariidae species and, one species of Gelechiidae fed only on new leaves. These species showed a short life cycle, which was very syncronized with the host plant foliar phenology. Among the species feeding on mature leaves, 36 were considered polyphagous and, these showed a large variation in the use of the food resource. Twenty-six species were found only on R. montana, 58% were very rare, a character that difficults the analysis of their dietary range. The monophagous species on R. montana were: Chlamydastisplatyspora (Meyrick) (Elachistidae), Stenoma cathosiota Meyrick (Elachistidae), Idalus prop. sublineata (Rothschild) (Arctiidae), and Eomichla sp. (Oecophoridae).

Alternative food sources and overwintering feeding behavior of the boll weevil, Anthonomus grandis boheman (coleoptera: curculionidae) underthe tropical conditions of central Brazil

The boll weevil causes serious damage to the cotton crop in South America. Several studies have been published on this pest, but its phenology and behavior under the tropical conditions prevailing in Brazil are not well-known. In this study the feeding behavior and main food sources of adult boll weevils throughout the year in Central Brazil was investigated. The digestive tract contents of insects captured in pheromone traps in two cotton fields and two areas of native vegetation (gallery forest and cerrado sensu stricto) were analyzed. The insect was captured all through the year only in the cerrado. It fed on pollen of 19 different plant families, on Pteridophyta and fungi spores and algae cysts. Simpson Index test showed that the cerrado provided greater diversity of pollen sources. In the beginning of the cotton cycle, the plant families used for pollen feeding were varied: in cotton area 1, the weevil fed on Poaceae(50 percent), Malvaceae and Smilacaceae (25 percent each); in cotton area 2 the pollen sources were Malvaceae (50 percent), Asteraceae (25 percent) and Fabaceae and Clusiaceae (25 percent each); in the cerrado they were Chenopodiaceae (67 percent) and Scheuchzeriaceae (33 percent). No weevils were collected in the gallery forest in this period. After cotton was harvested, the family Smilacaceae was predominant among the food plants exploited in all the study areas. These results help to explain the survivorship of adult boll weevil during cotton fallow season in Central Brazil and they are discussed in the context of behavioral adaptations to the prevailing tropical environmental conditions.

Biology and occurrence of Inga Busk species (Lepidoptera: Oecophoridae) on Cerrado host plants

We sampled Inga Busk species caterpillars weekly in the cerrado on 15 plants of Diospyros burchellii Hern. (Ebenaceae) from January 2002 to December 2003, on 30 plants of Caryocar brasiliense (Caryocaraceae) from July 2003 to June 2004, and since 1991 on several other plant species. In total we found 15 species of Inga on cerrado host plants. Nine species were very rare, with only one to five adults reared. The other six species occurred throughout the year, with higher abundance during the dry season, from May to July, coinciding with overall peaks of caterpillar abundance in the cerrado. Caterpillars of the genus Inga build shelters by tying and lining two mature or old leaves with silk and frass, where they rest and develop (a common habit found in Oecophorinae). The final instar builds a special envelope inside the leaf shelter, where it will complete the larval stage and pupate. The species are very difficult to distinguish in the immature stages. External features were useful in identifying only four species: I. haemataula (Meyrick), I. phaecrossa (Meyrick), I. ancorata (Walsingham), and I. corystes (Meyrick). These four species are polyphagous and have wide geographical distributions. In this paper we provide information on the natural history and host plants of six Inga species common on cerrado host plants, for which there are no reports in the literature.

Dada a ausência de informações sobre a biologia de lagartas que ocorrem em plantas de cerrado, apresentamos aqui algumas informações sobre larvas do gênero Inga Busk. Lagartas foram coletadas, semanalmente, em 15 indivíduos de Diospyros burchelli Hern. (Ebenaceae), de janeiro de 2002 a dezembro de 2003, em 30 indivíduos de Caryocar brasiliense Camb. (Caryocaraceae), de julho de 2003 a junho de 2004 e, em várias outras espécies de plantas desde 1991. No total foram encontradas 15 espécies de Inga em plantas de cerrado, no DF. Nove espécies foram raras com até cinco adultos obtidos em criação no laboratório. As outras seis espécies ocorreram durante o ano sendo mais abundantes entre maio e julho (estação seca), o que coincide com a época de maior abundância de lagartas no cerrado. As lagartas do gênero Inga constroem abrigos, juntando duas folhas maduras ou velhas com fios de seda, onde se alimentam e desenvolvem (um hábito comum entre os Oecophorinae). Larvas de último instar constroem, dentro do abrigo, um tipo de envelope onde completam seu desenvolvimento e empupam. A separação das espécies das lagartas é muito difícil. Características externas permitem o reconhecimento de apenas quatro espécies de Inga: I. haemataula (Meyrick), I. phaecrossa (Meyrick), I. ancorata (Walsingham), and I. corystes (Meyrick). Essas quatro espécies têm ampla distribuição geográfica e são polífagas. Neste artigo, apresentamos informações não encontradas na literatura sobre a história natural de seis espécies de Inga comuns em plantas hospedeiras de cerrado.

Temporal and spatial variation of Stenoma cathosiota Meyrick (Lepidoptera: Elachistidae) caterpillar abundance in the cerrado of Brasilia, Brazil

The caterpillars of Stenoma cathosiota Meyrick feed on Roupala montana Aubl. (Proteaceae) in the cerrado of the Distrito Federal, Brazil. They construct shelters by joining leaves of the plant where they feed and pupate. The caterpillars are parasitized by a wasp (Hymenoptera: Brachonidae), which emerges from the pupae. Caterpillar abundance and parasitism frequency were associated in an area of frequently burned cerrado (biennial fire) and in another area that burns sporadically (1987 and 1994). For S. cathosiota, the variation among years in a single area, with sporadic fires, was greater than the variation among areas with different fire regimes. Caterpillar abundance among years was significantly different in the area that burns sporadically (chi² = 24.06; df. = 1; P = 0.000). However, there were no significant differences on caterpillar abundance between areas for the same period (chi² = 3.45; df. = 1; P = 0.063). Parasitism frequency was high, reaching 29 percent of the collected caterpillars, and did not differ among areas. The great temporal variation in abundance of lepidopteran caterpillars in the cerrado makes it difficult to determine the effects that fire exerts over this fauna.

As lagartas da mariposa Stenoma cathosiota Meyrick alimentam-se de folhas de Roupala montana Aubl. (Proteaceae) em áreas de cerrado do Distrito Federal. Elas constroem abrigos juntando folhas da planta onde se alimentam e empupam. São parasitadas por uma vespa (Hymenoptera: Braconidae) que emerge da pupa. A abundância de lagartas de S. cathosiota e a freqüência do parasitismo foram comparadas em duas áreas de estudo: uma com queimadas freqüentes (bienal) e a outra com queimadas esporádicas (1987 e 1994). Na área com baixa freqüência de queimada, a variação na abundância das lagartas entre anos foi significativamente diferente (chi² = 24,06; gl. = 1; P = 0,000). No entanto, a variação na abundância de lagartas entre áreas, para o mesmo período de tempo, não diferiu estatisticamente (chi² = 3,45; gl. = 1; P = 0,063). A freqüência do parasitismo foi alta, ocorrendo em 29 por cento das lagartas coletadas e não diferiu entre as áreas. A grande variação temporal na abundância de lagartas no cerrado dificulta a determinação dos efeitos do fogo sobre essa fauna.

Lepidópteros folívoros em Roupala montana Aubl. (Proteaceae) no Cerrado Sensu Stricto / Folivore caterpillars on Roupala montana Aubl. (Proteaceae) in Cerrado Sensu Stricto

No cerrado a riqueza de espécies de lepidópteros é alta e confirmada por registros de adultos, mas o conhecimento sobre as interações das lagartas com suas plantas hospedeiras ainda é incipiente. Os objetivos deste trabalho foram conhecer a riqueza de espécies de lepidópteros folívoros em Roupala montana Abl., a idade relativa das folhas consumidas pelas espécies e suas amplitudes de dietas. Os dados foram coletados em áreas de cerrado sensu stricto de Brasília de 1991 a 2004. As lagartas encontradas foram coletadas e criadas no laboratório. Foram registradas 62 espécies de lepidópteros de 22 famílias, consumindo folhas jovens (8 por cento) e maduras (92 por cento) de R. montana. Cerconota sciaphilina (Zeller) (Elachistidae), duas espécies de Gracillariidae e uma de Gelechiidae consumiram somente folhas jovens e, apresentaram ciclo de vida curto e sincronizado com a fenologia foliar da planta hospedeira. Das espécies que consomem folhas maduras, 36 foram consideradas polífagas e mostraram variação muito grande na utilização do recurso. Vinte e seis espécies foram encontradas somente em R. montana, sendo que 58 por cento delas são bastante raras, o que dificulta análise de amplitude de dieta. As espécies monófagas em R. montana foram Chlamydastis platyspora (Meyrick) (Elachistidae), Stenoma cathosiota Meyrick (Elachistidae), Idalus prop. sublineata (Rothschild) (Arctiidae) e Eomichla sp. (Oecophoridae).