Fruit colour and edge effects poorly explains frugivorous bird-plantinteractions in disturbed semideciduous forests / A cor dos frutos e o efeito de borda não explicam as interações entre aves frugívoras e plantas em fragmentos florestais semidecíduos alterados

Fruit colour is considered an important feature mediating interactions between plants and frugivorous birds. Despite that, colour mediated interactions are context-dependent, and habitat disturbances may affect how frugivorous birds perceive fruit colours. This study assessed the influence of fruit colour and edge effect on the consumption of artificial fruits by frugivorous birds in three disturbed semideciduous forests in southeastern Brazil. In each of those areas, we performed a field experiment in which we placed artificial fruits of three different colours on plants and recorded their consumption by birds. Red-coloured fruits were ingested more often than yellow, but neither of them was consumed differently from dark-blue. Edge effect only affected consumption of yellow fruits. Our data neither support the hypothesis of preferential consumption of the highest contrasting colours nor of increased fruit consumption in the forest interior. These findings indicate that colour and edge effects, as well as the interaction between them, may not be strong predictors of fruit choice by birds in disturbed environments, especially because generalist species, which are less sensitive to the physical alterations in forests, are favoured in these areas.

A cor dos frutos é importante nas interações entre plantas e aves. Apesar disso, as interações mediadas por cores são contexto-dependentes e as alterações no habitat podem afetar a maneira como os frugívoros percebem a coloração dos frutos. Este estudo avaliou a influência da cor e do efeito de borda no consumo de frutos artificiais por aves em três florestas semidecíduas degradadas no sudeste brasileiro. Em cada uma dessas áreas, foi conduzido um experimento no qual foram colocados frutos artificiais de três cores diferentes nas plantas e foi registrado o seu consumo pelas aves. Os frutos vermelhos foram mais consumidos do que os amarelos, mas nenhum deles foi consumido mais frequentemente do que os azulescuros. O efeito de borda afetou apenas o consumo de frutos amarelos. Nossos dados não suportam as hipóteses de consumo preferencial da coloração mais contrastante nem do aumento do consumo de frutos no interior dos fragmentos. Estes resultados indicam que a cor dos frutos, o efeito de borda e a interação entre estes dois fatores, não são fortes preditores da escolha do fruto por aves em ambientes degradados, principalmente pela ocorrência de espécies generalistas nestas áreas, que são menos sensíveis às alterações físicas nos fragmentos.

Sensory cues employed for the acquisition of familiarity-dependent recognition of a shoal of conspecifics by climbing perch (Anabas testudineus Bloch).

In this study we showed that a freshwater fish, the climbing perch (Anabas testudineus) is incapable of using chemical communication but employs visual cues to acquire familiarity and distinguish a familiar group of conspecifics from an unfamiliar one. Moreover, the isolation of olfactory signals from visual cues did not affect the recognition and preference for a familiar shoal in this species.

Behavioural biology of Chagas disease vectors

Many arthropod species have adopted vertebrate blood as their main food source. Blood is rich in nutrients and, except for the presence of parasites, sterile. However, this food source is not freely available, nor is obtaining it devoid of risk. It circulates inside vessels hidden underneath the skin of mobile hosts that are able to defend themselves and even predate the insects that try to feed on them. Thus, the haematophagous lifestyle is associated with major morphological, physiological and behavioural adaptations that have accumulated throughout the evolutionary history of the various lineages of blood-sucking arthropods. These adaptations have significant consequences for the evolution of parasites as well as for the epidemiology of vector-transmitted diseases. In this review article, we analyse various aspects of the behaviour of triatomine bugs to illustrate how each behavioural trait represents a particular adaptation to their close association with their hosts, which may easily turn into predators. Our aim is to offer to the reader an up-to-date integrative perspective on the behaviour of Chagas disease vectors and to propose new research avenues to encourage both young and experienced colleagues to explore this aspect of triatomine biology.