Variation in a Darwin Wasp (Hymenoptera: Ichneumonidae) Community along an Elevation Gradient in a Tropical Biodiversity Hotspot: Implications for Ecology and Conservation.

Understanding how biodiversity varies from place to place is a fundamental goal of ecology and an important tool for halting biodiversity loss. Parasitic wasps (Hymenoptera) are a diverse and functionally important animal group, but spatial variation in their diversity is poorly understood. We survey a community of parasitic wasps (Ichneumonidae: Pimplinae) using Malaise traps up a mountain in the Brazilian Atlantic Rainforest, and relate the catch to biotic and abiotic habitat characteristics. We find high species richness compared with previous similar studies, with abundance, richness, and diversity peaking at low to intermediate elevation. There is a marked change in community composition with elevation. Habitat factors strongly correlated with elevation also strongly predict changes in the pimpline community, including temperature as well as the density of bamboo, lianas, epiphytes, small trees, and herbs. These results identify several possible surrogates of pimpline communities in tropical forests, which could be used as a tool in conservation. They also contribute to the growing evidence for a typical latitudinal gradient in ichneumonid species richness, and suggest that low to medium elevations in tropical regions will sometimes conserve the greatest number of species locally, but to conserve maximal biodiversity, a wider range of elevations should also be targeted.

Male-male contests for mates, sexual size dimorphism, and sex ratio in a natural population of a solitary parasitoid.

Understanding how different behavioural and life history traits interact is fundamental to developing ethological theory. Here we study the interaction of male-male competition for mates and sexual size dimorphism in a solitary wasp, with implications for sex allocation. In Hymenoptera, females are normally larger than males suggesting that males do not benefit as much as females from larger size. However, in our focal species, a solitary Eurytoma wasp, males compete for mates by pairwise contests at female emergence sites, suggesting that male size may strongly affect fitness. In contests observed in the field, larger males were more likely to win fights, and males fighting at female emergence sites were much larger than average males. Males showed higher variance in body size than females, such that all the smallest individuals were males, a majority of medium-to-large individuals were female, but the majority of largest individuals were male. Our data suggest that sexual size dimorphism in this species has been affected by intra-sexual selection for male size, which may have implications for sex allocation.

Predação de sementes de Allagoptera arenaria (Gomes) O'Kuntze (Arecaceae) por Pachymerus nucleorum Fabricius (Coleoptera, Chrysomelidae, Bruchinae) / Seed predation on Allagoptera arenaria (Gomes) O'Kuntze (Arecaceae) by Pachymerus nucleorum Fabricius (Coleoptera, Chrysomelidae, Bruchinae)

A predação de sementes da palmeira Allagoptera arenaria (Gomes) O'Kuntze, 1891(Arecaceae) por Pachymerus nucleorum Fabricius, 1972 foi avaliada de setembro de 2003 a setembro de 2005 no Parque Nacional da Restinga de Jurubatiba (RJ). A biologia e o comportamento de P. nucleorum em A. arenaria e as taxas de predação de sementes foram descritas. Frutos encontrados sob 50 palmeiras foram coletados, mensalmente, em cada uma das duas áreas amostradas no PNRJ (mata de cordão arenoso e formação arbustiva aberta de Clusia Sclthdl, Clusiaceae). A avaliação dos cocos predados foi feita a partir da contagem dos orifícios de saída dos bruquíneos no campo, da emergência dos insetos no laboratório e da abertura dos frutos remanescentes. Através de observações e experimentos em 60 infrutescências, verificou-se que a oviposição de Pachymerus nucleorum em A. arenaria ocorre na infrutescência ainda em desenvolvimento diferentemente de registros na literatura em outras espécies de palmeiras, onde a oviposição ocorre nos frutos no chão. A predação dos frutos por P. nucleorum foi de 29,3 por cento na área de mata de cordão arenoso e 20,6 por cento na formação arbustiva aberta de Clusia. O ciclo de vida de P. nucleorum foi bastante longo e com amplitudes bem grandes dentro de uma mesma amostra, o que sugere uma possível diapausa em alguma fase do seu ciclo de vida.

Seed predation on Allagoptera arenaria (Gomes) O'Kuntze, 1891(Arecaceae) palm by Pachymerus nucleorum Fabricius, 1972 was evaluated from September 2003 to September 2005 at the Parque Nacional da Restinga de Jurubatiba (PNRJ), Rio de Janeiro, Brazil. The biology and behaviour of P. nucleorum on A. arenaria and predation rates were described. Fruits found beneath 50 palms were collected, monthly, for each one of the two sampled areas at PNRJ (ridge forest and Clusia Sclthdl (Clusiaceae) open shrubland formation). The evaluation of preyed fruits was done by counting exit holes of Bruchinae in the field, the emergence of these insects in the laboratory and from fruits dissected. It was verified that Pachymerus nucleorum oviposit on young developing infrutescences, different from literature records for other palm species, for which oviposition takes place on the fruit already on the ground. Fruit predation by P. nucleorum was 29.3 percent at ridge forest and 20.6 percent at Clusia open shrubland formation. The life cycle of P. nucleorum was long and with wide range of variation within samples, what suggests a possible diapause in some stage of life cycle.

Composição, abundância e notas sobre a ecologia de espécies de larvas de lepidópteros associadas a cinco espécies de plantas hospedeiras no Parque Nacional da Restinga de Jurubatiba, RJ / Composition, abundance and notes on ecology of lepidopteran larvae associated with five plant species in Parque Nacional da Restinga de Jurubatiba, RJ

Com o objetivo de descrever a composição, ocorrência temporal e aspectos ecológicos das espécies de larvas de Lepidoptera associadas a cinco espécies de plantas: Erythroxylum ovalifolium e E. subsessile (Erythroxylaceae), Manilkara subsericea (Sapotaceae), Protium icicariba e P. heptaphyllum (Burseraceae), 1.455 plantas foram vistoriadas durante o período de Julho de 2003 a Agosto de 2005 no Parque Nacional da Restinga de Jurubatiba (PNRJ). Foram encontradas 32 espécies de Lepidoptera associadas a essas cinco espécies de plantas hospedeiras, sendo que as quatro espécies mais abundantes pertenciam à família Elachistidae. Manilkara subsericea apresentou o maior número de espécies de Lepidoptera associadas, 14 espécies, seguida por E. ovalifolium, com 10 espécies, P. icicariba, com sete, E. subsessile com seis e P. heptaphyllum com duas espécies de Lepidoptera associadas. Apenas uma das 32 espécies de Lepidoptera criadas apresentava hábito gregário e 56 por cento utilizavam algum tipo de abrigo para alimentação e/ou defesa. Seis espécies de Lepidoptera identificadas (27 por cento) eram polífagas, três (14 por cento) oligófagas e 13 (59 por cento) tiveram apenas uma única espécie de planta hospedeira registrada. As espécies mais abundantes de mariposas apresentaram dois períodos reprodutivos no ano, predominantemente, no inverno e outono. Fatores abióticos, como a forte insolação na primavera e verão na formação aberta de restinga, podem ser importantes determinando esse padrão temporal de reprodução dos insetos, mas não podemos descartar também fatores bióticos como a pressão de inimigos naturais.

In order to describe the species composition, temporal occurrence and ecological aspects of larvae associated with five plant species: Erythroxylum ovalifolium and E. subsessile (Erythroxylaceae), Manilkara subsericea (Sapotaceae), Protium icicariba and P. heptaphyllum (Burseraceae), 1.680 plants were bimonthly surveyed from July of 2003 to August of 2005 in the Parque Nacional da Restinga de Jurubatiba (PNRJ). Thirty two species of Lepidoptera were reared from these five host plants, and the most abundant four species belonged to the Elachistidae. Manilkara subsericea showed the greatest number of Lepidoptera species associated, 14 species, followed by E. ovalifolium (10 species), P. icicariba (seven species), E. subsessile (six species) and P. heptaphyllum (two species). Only one out of the 32 species of Lepidoptera was gregarious and 56 percent used any kind of shelter to get food or for defence. Six Lepidoptera species (27 percent) were polyphagous, three (14 percent) oligophagous and 13 (59 percent) had just only one host plant species recorded. The most abundant species of moths exhibitted two reproductives periods in the year, predominantly in winter and autumn. Abiotic factors, such as strong insolation during spring and summer in the open scrub vegetation of restinga, may be very important in producing this temporal pattern of insect reproduction, but we cannot neglect biotic factors like natural enemies.