Darwin's finches treat their feathers with a natural repellent.

Darwin's finches are highly innovative. Recently we recorded for the first time a behavioural innovation in Darwin's finches outside the foraging context: individuals of four species rubbed leaves of the endemic tree Psidium galapageium on their feathers. We hypothesised that this behaviour serves to repel ectoparasites and tested the repellency of P. galapageium leaf extracts against parasites that negatively affect the fitness of Darwin's finches, namely mosquitoes and the invasive hematophagous fly Philornis downsi. Mosquitoes transmit pathogens which have recently been introduced by humans and the larvae of the fly suck blood from nestlings and incubating females. Our experimental evidence demonstrates that P. galapageium leaf extracts repel both mosquitoes and adult P. downsi and also inhibit the growth of P. downsi larvae. It is therefore possible that finches use this plant to repel ectopoarasites.

Interactions between the Avian Parasite, Philornis downsi (Diptera: Muscidae) and the Galapagos Flycatcher, Myiarchus magnirostris Gould (Passeriformes: Tyrannidae).

An incidental observation of the fly Philornis downsi parasitizing a Galapagos Flycatcher (Myiarchus magnirostris) nest has revealed new insights into the searching behavior and biology of this invasive fly parasite and its interactions with endemic landbirds in the Galapagos Islands. Observations suggest that P. downsi relies on olfactory cues, or olfactory cues combined with the activity of adult birds, to locate nests and that flies continue to visit nests when chicks are >3 d old. At least 200 eggs were laid by P. downsi in different parts of the nest and >40 early-instar larvae were found inside the head of one chick, with additional larvae found in the base of the nest. Parasitism was the likely cause of mortality of both chicks found in or near the nest. This description of P. downsi parasitizing chicks of M. magnirostris highlights the vulnerability of this endemic bird species to this invasive fly.

Microstructure and diversity of the bursa copulatrix wall in Tortricidae (Lepidoptera).

The inner surface and muscle structure of the bursa copulatrix are examined for the first time with Electron Microscopy in some representatives of the family Tortricidae (Lepidoptera). The internal microprotuberances reveal taxon dependent characters unstudied in the Lepidoptera until now. Acanthae occur in almost all taxa studied, whereas ctenidia and papillae are found only in representatives of Tortricinae and Olethreutinae, respectively. Muscles are radially arranged from the signa. Areas of muscle insertion on the bursal wall are not covered by other muscle fibers. Muscle attachments to evaginated areas, e.g. capitulum and diverticulum, suggest an apodeme role for these structures, correlated with long protruding signa. The potential evolutionary and adaptive significance of these new findings are discussed.