In song-learning birds, male song shows a large inter-individual variation that frequently plays an important role in intra- and inter-sexual selection. In other bird groups, such as Galliformes, song learning is absent, ...

El reconocimiento de parentela en grupos sociales de artrópodos puede ocurrir por diferentes tipos de estímulos, como por ejemplo los compuestos excretados de la cutícula. Un rasgo posiblemente ancestral de las arañas ...

We recorded 27 species of Charadriiformes on the mud flats of Chomes, Golfo de Nicoya, Costa Rica, during biweekly censuses over one year. These were grouped taking into account their abundance and permanence on the flat. ...

The use of carrion to feed spiderlings has never previously been observed in spiders. Here we show that the theridiid Theridion evexum Keyserling 1884 stored dead insectan prey for up to one week prior to the emergence of ...

Sooty-faced Finches (Lysurus crassirostris) occur in dense undergrowth of wet forests that border streams along the Caribbean slope of Costa Rica between 600 to 1500 m in altitude. Its distribution is from Cordillera de ...

The koinobiont ectoparasitoids of spiders in the Polysphincta genus group are divided into two well-supported clades. Species in one clade parasitize spiders in the higher araneoid group, and the behaviour of these ...

Standard accounts of how spiders obtain food without masticating their prey are probably largely wrong. Species in the families Uloboridae, Thomisidae, Araneidae and Theridiidae do not inject digestive fluid into the prey’s ...

In Costa Rican coastal and marine environments (e.g., estuaries, mud- flats, islands, open ocean) 96 bird species have been recorded, 11% of the total avifauna in the country. This high diversity is primarily explained by ...

The koinobiont ectoparasitoid Zatypota petronae Gauld (Ichneumonidae) parasitizes medium-sized immatures of the cobweb spider Theridion evexum Keyserling (Theridiidae). Zatypota petronae apparently attacks the spider inside ...

Adaptive flexibility in response to environmental variation is often advantageous and occurs in many types of traits in many species. Although the basic designs of the orb webs of a given species are relatively uniform, ...