No abstract

Phytophagous insects may choose host plants based on conditions that enhance offspring performance. However, some insect species may also select plants based on attributes that enhance their own performance regardless of the consequences for offspring survival. An approach evaluating both hypotheses could provide a more comprehensive understanding of the host plant selection by phytophagous insects. In this study, we described the life stages of a Neotropical stink bug, Edessa contermina, co-occurring on Byrsonima verbascifolia plants in a conservation area of the Brazilian Savannah. We also empirically evaluated how food supply, shelter availability and competitors' density on the host plants affected the densities of nymphs, adults and mating pairs. We identified and described five life stages of E. contermina. The amount of plant resources did not explain the nymph, adult and mating pairs' density. However, adults and mating pairs chose plants with a low density of nymphs, probably because egg laying on the host plants with a high density of competitors may negatively affect offspring performance. ARTICLE HISTORY

Filarid nematodes are transmitted by arthropod vectors. In the vertebrate host, they inhabit the cardiovascular, pulmonary, and lymphatic system. Although most bird infections are not considered pathogenic, there may be an impact on fitness. Blood smears were performed to verify the intensity of the infection and to morphometrically analyse and describe the microfilariae found in individuals of Antilophia galeata captured in a fragment of the Cerrado forest. The microfilariae were photographed, and morphometry analysis was performed using the ImageJ software. One individual was infected (14.2%; n = 7) but with a high intensity of infection (42 microfilariae). It is suggested that the microfilariae found belong to the genus Eufilaria spp., since all specimens presented the diagnostic characteristics of the taxon (absence of sheath, pointed tail, and length less than 200 μm). This is the first time that microfilariae parasitising A. galeata have been recorded. Considering that microfilariae records are rare in Brazilian wild birds, this record may be useful to support further studies and contribute to the understanding of the conservation of the host species.

Changes in the amounts and proportions of leukocytes, known as leucocyte profiles, have been documented for several bird species and have been used to measure stress levels in these animals. The present work ascertained the biological and ecological attributes that influence the leukocyte profile of Antilophia galeata (Lichtenstein, 1823), the helmeted manakin. This species has been deemed useful in ecological studies because it responds to environmental changes. Blood samples drawn from 89 individuals of A. galeata captured in a Cerrado forest fragment were subjected to analysis under optical microscopy to identify and quantify leukocytes and micronuclei. The number of lymphocytes was greater for males, non-reproductive individuals and individuals infected with ticks. None of the leukocyte components differed in relation to age, molting or body condition index. The amount of micronuclei was correlated with values for total leukocytes, H/L ratio, heterophils, basophils and monocytes. The results suggest that reproduction may be an immunosuppressive factor for the species, producing sexual differences in lymphocyte availability. In addition, biomarkers of genotoxic damage (micronuclei) were related to the amount of leukocytes, indicating that individuals may be sensitive to environmental disturbances. Leukocyte profiles can be considered a useful tool for addressing ecological questions that are relevant to the conservation of species in degraded environments.

Blood parasites can infect myriad avian species and thereby affect the fitness and survival of their hosts. There is wide interspecific variation in parasite prevalence related to biological, ecological, and evolutionary host factors. This study aimed to determine the blood parasite prevalence in avian species from the Brazilian Cerrado and to investigate the associations among biomass, body condition, and blood parasitism. A total of 1,098 blood smears from 549 individuals (56 species) collected in four forest fragments were analyzed. Of these, 109 (19.85%) individuals from 33 species were infected: 13 (2.36%) were positive for Haemoproteus and 103 (18.76%) for Plasmodium. There was co-infection between both genera of parasites in 7 individuals. Among bird species, prevalence ranged from zero to 100%. There were significant positive correlations between prevalence and biomass and the body condition index. Hemosporid vectors track their hosts by carbon dioxide detection. Since large organisms emit more carbon dioxide, our results suggest that larger birds may be more susceptible to hemosporid vectors. Additionally, species with higher body condition indices can be more tolerant to parasites, possibly because they have more energy reserves. This study showed that species with higher biomass and body condition indices were associated with higher blood parasite prevalence, a finding that suggests these factors are efficient predictors to explain the interspecific variations. This information could be important for the understanding parasite-host relationships and useful for bird conservation programs.