Margarete V. Macedo

Biology and Seasonality of Fulcidax monstrosa (F.) (Chrysomelidae: Chlamisinae)

Abstract The phenology of Fulcidax monstrosa (F.) on its host plant Byrsonima sericea DC. was studied from November 2000 to June 2003 at the Restinga de Jurubatiba National Park, Rio de Janeiro, Brazil. During this period, observations on the biology and behavior of the species were also conducted in the field and in laboratory. The female lays single eggs on young stems of its host plant and covers them with feces, building an excremental shell. The hatched larva remains within it and adds more of its own feces to the case as it grows. After a maximum of four months, the larva pupates within the case, which remains closed for another four months before adult emergence. Diapause seems to occur in the adult stage inside the pupal case before emergence. Fulcidax monstrosa is a univoltine species and showed a highly seasonal distribution along the years for all stages of development. Climatic factors as well as resource availability are suggested to influence the species seasonality.

Altitudinal and temporal distribution of Plagiometriona Spaeth, 1899 (Coleoptera, Chrysomelidae, Cassidinae) in a tropical forest in southeast Brazil

Abstract Species richness and abundance of seven Plagiometriona species on their host plants were studied along a single trail in the mountainous Serra dos Órgãos National Park in the State of Rio de Janeiro, Brazil. Six sites were chosen along an altitudinal gradient ranging from 1300 m to 2050 m, where all Solanaceae host plants were inspected in search of adults every two months from June 2006 to June 2007. Species richness did not vary clearly with altitude, but abundance increased up to 1800 m, where the highest mean host plant density was found, and abruptly decreased at the last elevational site. Most species showed a restricted distribution and just one occurred across the entire gradient. For at least four species, altitudinal distribution seems to be strongly related to host plant availability, while for the others it is difficult to access which factors are decisive, due to their low numbers. Only in October all species were found in the field, although February was the month with the highest total abundance. Over the course of the study, the greatest abundances were recorded from October to February, comprehending the hottest and rainiest months, and the lowest abundances were found from June to August, which include the coldest and driest months. Thus, species seasonal distribution, supported by other studies in the same area, seems to be related to the local climate.

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

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% used any kind of shelter to get food or for defence. Six Lepidoptera species (27%) were polyphagous, three (14%) oligophagous and 13 (59%) 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.

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.

Biology and phenology of three leaf beetle species (Chrysomelidae) in a montane forest in southeast Brazil.

Abstract The population phenology of the cassidines, Coptocycla arcuata and Omaspides trichroa, and the chrysomeline, Platyphora axillaris, was studied at Serra dos Órgãos National Park, State of Rio de Janeiro, southeast Brazil. Monthly surveys of larvae and adults were conducted between 2008 and 2011 at approximately 1000 m altitude on their respective host plants, Cordia polycephala (Boraginaceae), Ipomoea philomega (Convolvulaceae) and Solanum scuticum (Solanaceae). This is the first observation of larviparity and host record for Platyphora axillaris. Although having different life history traits, all species showed similar phenologies. They were abundant from October to March, months of high temperatures and intense rainfall, with two distinct reproductive peaks in the same season. Abundance dropped abruptly during the coldest and driest months, from May to August. Frequently none of these species were recorded during June and July. This phenological pattern is similar to other Chrysomelidae living in subtropical areas of Brazil. Temperature and rainfall appear to be the major factors influencing the fluctuation of these three species.

Elevation and temporal distributions of Chrysomelidae in southeast Brazil with emphasis on the Galerucinae

Abstract In this study we present an ecological pattern of elevation and temporal variations found in the Chrysomelidae in one of the highest mountains in southeastern Brazil. Monthly surveys using an entomological sweep-net were conducted between April 2011 and June 2012, at five different elevations (800 m, 1000 m, 1750 m, 2200 m and 2450 m). A total of 2318 individuals were collected, belonging to 91 species. The elevation and temporal patterns of distribution of Chrysomelidae were heavily dominated by the Galerucinae. This subfamily had the highest richness and abundance at intermediate altitudes and during the rainy season. Probably the food availability as well as abiotic factors this time of the year favor the development of Galerucinae. Also, most of the more abundant Galerucinae species showed broad elevation ranges but approximately 20% of these species were only collected on the mountaintop sites. We would expect these species to be ones most prone to extinction in a scenario of climate warming or even after local disturbances.

Biology and ecology of Mecistomela marginata (Thunberg, 1821) (Hispinae: Alurnini) in Brazil

The Hispinae are a relatively homogeneous subfamily in the Chrysomelidae most of which feed on monocot leaves, mainly Graminae and Palmae. Their larvae are usually leaf miners or free feeders between appressed leaves (Jolivet, 1989). The Neotropical tribe Alurnini ecologically is one of the most homogeneous in the subfamily, all the larvae feeding freely between leaves of Palmae. This tribe includes the largest species in the Chrysomelidae.

Three New Reports of Subsocial Tortoise Beetles from South America (Chrysomelidae: Cassidinae)

ABSTRACT Subsociality is known in 35 species in 10 genera of the chrysomelid subfamilies Cassidinae and Chrysomelinae. In Cassidinae, the behavior is clustered in two tribes, Eugenysini and Mesomphaliini, but unknown biologies of many of these species limit fine-scaled resolution of the origins and diversity of this interesting behavior. We report three new records of subsocial Cassidinae, Eugenysa martae Borowiec in Colombia, Omaspides (Omaspides) clathrata L. in French Guiana, and Paraselenis (S.) aulica in Brazil. Females guard larvae and pupae; larvae retain exuvio-fecal shields in some stages. Longer-term study of P. (S.) aulica on the host Ipomoea (Convolvulaceae) revealed that eggs, larvae, and pupae are gregarious and guarded by the female. Larvae lose the defensive exuvio-fecal shields in older instars. Females will mate despite being occupied with brood care. A wasp, Emersonella sp. (Hymenoptera: Eulophidae), and a tachinid fly (Diptera) were observed associated with and reared from juveniles. Our report increases the dataset of documented subsocial cassidines to 26 species, with 23 in Mesomphaliini and three in Eugenysini.

A chalcid wasp acts chiefly as a hyperparasitoid by mostly using small uncommon hosts

Although ovipositing insects may predominantly use resources that lead to high offspring quality, exceptions to this rule have considerably aided understanding of oviposition decisions. We report the frequency of host species use by a solitary facultative hyperparasitoid, Brachymeria subrugosa Blanchard (Hymenoptera: Chalcididae). In our samples, the wasp attacks the large pupae of the moth Gonioterma indecora Zeller (Lepidoptera: Elachistidae), as well as the considerably smaller, and rarer, pupae of two of its other parasitoids. Consistent with conditional sex allocation models, the wasp produced mainly female offspring on the largest (moth) host, an unbiased sex ratio on the middle‐sized (parasitoid) host, and only males on the smallest (parasitoid) host. Adult offspring size was correlated with the size of the host attacked. These features strongly suggest that the two smaller, primary parasitoid, hosts produce lower‐quality offspring. Despite being more common, the proportion of hosts from which parasitoids emerged was lowest (14%) on the largest host species, and highest on the rarer middle‐sized (34%) and smallest (30%) hosts. This suggests that costs or constraints on attacking high‐quality primary hosts may be a selective force favouring the evolution of hyperparasitism.

Larvas de insetos associadas a Clusia hilariana Schltdl. (Clusiaceae) na Restinga de Jurubatiba, RJ, Brasil

Clusia hilariana is one of the most abundant plant species in the National Park playing important role at the sucessional dynamic of the restinga ecosystem. This paper presents the composition and ecological aspects of caterpillars species found on C. hilariana. From 40 plants monthy inspected, fourteen species of Lepidoptera were obtained. Chloropaschia granitalis (Pyralidae) was the most abundant species feeding on this plant species.