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 ...

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 ...

The ratio of brain size to body size (relative brain size) is often used as a measure of relative investment in the brain in ecological and evolutionary studies on a wide range of animal groups. In birds, a variety of ...

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 characteristics and designs of webs provide valuable information on ecology, behavior and phylogenetic relationships. Characters are often obtained from detailed analyses of web photographs. We describe new methods to ...

Information theory and its indices were developed for human communication to predict the amount of information transferred in a message. One such index, the Shannon-Weiner index (SWI), has often been used to analyse ...

Anthropogenic noise (≤ 3 kHz) can affect key features of birds’ acoustic communication via two different processes: (1) song-learning, because songbirds need to hear themselves and other birds to crystallize their song, ...

Adult females of Helvibis longicauda accumulated tiny pieces of vegetation in the mesh of their webs. The amount of debris accumulated was much greater in webs of spiders with either egg sacs, spiderlings or juveniles than ...