We present a detailed description of the predatory behavior of the beetle Canthon virens Mannerheim, 1829, on the leafcutter ant Atta sp. We observed 51 acts of predation, which were also recorded on film and subjected to behavioral analysis. Canthon virens exhibited 28 behaviors while predating upon Atta sp. queens. Adult beetles search for queens while flying in a zigzag pattern, 15 to 20 cm above the ground. After catching a queen, the predator stands on its back and starts cutting the queen cervix. Once the prey is decapitated, the predator rolls it until an insurmountable obstacle is reached. The distance from the site of predation to the obstacle can vary widely and is unpredictable. The beetle rolling the queen also buries it in a very peculiar way: first, it digs a small hole and pulls the queen inside, while another beetle is attached to the prey. The burial process takes many hours (up to 12) and may depend on the hardness of the soil and the presence of obstacles. In general, one or two beetles are found in a chamber with the queen after it is buried. They make the brood balls, which serve as food for the offspring. This study contributes to the knowledge of the predatory behavior of Canthon virens, a predator poorly studied in Brazil and widespread in the country.

ABSTRACT. Spider cornrn unities (Araneae) on rubber tree (Hevea brasiliensis Muell. Arg.) plantations in São Paulo State, Brazil. The spider fauna co mpositi on of three rubber tree co mmercial plantations in the Northwest part of São Paulo State, Brazil , was characteri zed for both canopy and li tter strata. On seven occasions fram April 2000 to October 200 I, samples were taken by beating sheet and hand capture, res ulting in a total of 946 individuaIs, belonging to 24 fam ilies and 11 9 species. The most co mmon speci es were ltalaman santamaria Brescovil , 1997 and Teudis sp. (Anyphaenidae), Caslianeira sp. and Falconina aff. gracilis (Corinnidae), Paracleocnemis sp. (Philodramidae), lbo fypora nga ,wideae Mello-Leitão, 1944 (Pholcidae) , Chira spinipes (Taczanowiski , 1871 ) and Rudra sp. (Salticidae), A chaearanea hirla (Taczanowiski , 1873) and Coleosom.a jloridanum (Banks, 1900) (Theridiidae) and Coeldia sp. (Titanoecidae). Anyphaenidae, Theridi idae and Salticidae were the mosl abundant fami lies in the canopy, while Pholcidae and Co rinnidae in the litter. Spider abundance was found to be, in general , positively correlated to the litter volume and density of branches in the trees. The use of acaricides and insecticides for one plantation resulted in a dec rease in spider abundance for both strata. Abundance values among the sampl es suggest thal lhe canopy sp ider abundance decreases with lhe loss of leaves in lhe dry seaso n. Simultaneously, li tter spider abundance increased in lhi s season, because of the increase in lilter volume. The moSl aclive canopy spiders, like runners and stalkers, should be in vestigated For their potenlial as pest contraI agents. KEY WORDS . Spiders, Hevea brasiliensis, guild s, biodiversity, peslicides Aranhas co mpõ e m um dos gru pos de predadores nativos mais abundantes na maioria dos habitats terrestres, incl u indo os agríco las. Como inimigos naturais de artrópodes , as aranhas podem contr ibuir n a reg ul ação das pop ul ações de in se tos e de ácaros fitófagos, prejudiciais para cultivos comerciais. Por esta razão, as a ranhas têm sido ativamente preservadas em áreas agríco las da China (ZHAO 1993 apud MARC & CANARD 1997).Estudos sobre biodiversidade e ecolog ia básica desses p redadores em agroecossistemas são fundamentais para uma utilização m ais racional do ambiente pe lo homem. Levantamentos conduzidos em áreas agrícolas têm revelado alta d iversidade de aranhas (RI NALDI & FORTI 1997), o que afasta a idéia freqüente de q u e os sistemas agrícolas são sim plificados quanto à araneofauna.

The hunting spider communities of the Dionycha clade were studied 1986 through I 988 in fragmented woodlands and secondary agricultural habitats of the Botucatu area in Siio Paulo state, Brazil. The original vegetation of mainly tropical Atlantic rainforest (Mat a At/antica) was cleared already 70 years ago. In a total sample of over 1000 adult spiders, 247 species belonging to l2families were determined. A decreasing frequency and diversity of spiders was found if forest remnants were compared with sugar cane fields and cattle pasture. The specific composition of the spider fauna as surveyed in different habitats is discussed under ecological aspects and in relation to the history of land use.

ABSTRACT. Observations of the developmental biology of Loxosceles gaucho Gertsch, 1967, the brown spider of southeastern Brazil are scarce. The present study reports the method of individualized rearing of 18 populations of L. gaucho, kept in laboratory under varied diet conditions, and characterizes their nympho·imaginal period as well as factors related to their reproduction. Females built the first egg sac about 20 days after copulation and nymphs hatched 40 days after the laying date. Average offspring was 61.3 spiderlings and females usually built three to four successive egg sacs in a period of five to seven months. First nymphs initiated their predatOlY activity between the 5 th and 8 th days after hatching and the majority reached adulthood within six moults (range of five to eight) in approximately 15 to 17 months (male) and 15.5 to 18 months (female). The average sex ratio equa led 1.0:1.7 (male:female). The wide individual variability of this species intermoult intervals is herewith expressed by the "intermoult rate", which was fairly unitorm tor both intra and interpopulations and gives a relevant aspect for a general idea of the life cycles of spiders.

Abstract.  1. Sexuals of a leaf‐cutting ant, Atta bisphaerica Forel, left their nest for nuptial flights in October to December. 2. When leaving a nest, 53 of the 479 winged sexuals (or alates) observed (11.1%) carried up to three inquiline spiders of Attacobius luederwaldti. 3. Spiders exclusively selected winged sexuals, not workers, and preferred females, indicating their expectation of the stronger flight ability of females. Neither these sexuals nor workers that appeared out of the nest on flight days attempted to remove or attack spiders on the body of alates. 4. New qucens landing from their nuptial flight did not carry spiders, indicating that the spiders had left the ants in the sky to be dispersed by wind. 5. No spiders were found in more than 100 incipient nests, which were estimated to be 2–3 months old. This suggests that the spiders jumped off the alate during mid‐flight and dispersed on the wind to inhabit larger nests.