Associative learning in immature lacewings (<i>Ceraeochrysa cubana</i>)

It is known that many social insects and arthropod predators and parasitoids can learn the association between a resource and volatile cues. Although there are various studies on the effect of experience in immature arthropods on behavior later in adult life, not much is known about the effects of such experiences on immature behavior. This was investigated here in the lacewing Ceraeochrysa cubana (Hagen) (Neuroptera: Chrysopidae). Whereas adults of this lacewing feed on plant‐provided food and honeydew, larvae are voracious polyphagous predators of several insect pests, and therefore important for biological control. Hence, studying the foraging behavior and the effects of learning in immatures of this species is important. We exposed immatures to the volatile methyl salicylate (MeSA), which was either associated with food or with the absence of food. Subsequently, their response to this volatile was tested in an olfactometer. Immatures that had experienced the association of MeSA with food were attracted to it and immatures that were exposed to MeSA during food deprivation were repelled. Subsequently, predator immatures that had experienced the association between MeSA and food were released on a plant without food and were found to use this volatile in locating patches with food. In contrast, larvae without such experience were found equally on food patches with and without the volatile. We conclude that these immature predators are capable of learning the association between volatiles and food, or the absence of food, and use this during foraging

Produtividade e qualidade de frutos de mamão cultivar 'Golden' sob diferentes lâminas de irrigação e doses de potássio no norte de Espírito Santo Fruit yield and quality of papaya 'Golden' under different irrigation depths and potassium doses in the north of Espírito Santo State, Brazil

Este trabalho teve como objetivo estudar os efeitos de diferentes lâminas de irrigação e de doses de potássio sobre a produtividade e a qualidade dos frutos do mamoeiro cultivar Golden. O experimento foi realizado em área de produção agrícola comercial, localizada em Linhares - ES. O delineamento experimental foi em blocos casualizados, com arranjo em parcela subdividida, com três repetições. Os tratamentos foram compostos por cinco lâminas de irrigação, na parcela, e quatro doses de potássio, na subparcela, totalizando 20 tratamentos. As cinco lâminas de irrigação programadas foram de 50; 70; 90; 110 e 130% da ETo, e as quatro doses de potássio foram de 30; 42; 54 e 66 g de K2O por planta ao mês. Os elevados índices pluviométricos no período experimental (fevereiro-2005 a junho-2006) excederam em muito as necessidades hídricas das plantas, interferindo nos tratamentos, não permitindo variação significativa nas variáveis analisadas, principalmente em função das lâminas aplicadas. Durante os 11 meses e 21 dias de colheita, a produtividade média da cultivar Golden foi de 79,4 t ha-1, com média de 96 frutos por planta, que, no estádio I de maturação, apresentavam massa de 404 g, teor médio de SST de 10,11 ºBrix e firmeza da polpa e do fruto de 79,80 N e 126,19 N, respectivamente.<br>This work aimed to study the effects of different irrigation depths and potassium doses on yield and fruit quality of papaya cv Golden. The experiment was carried out in an area of commercial and agricultural production situated in Linhares - ES, Brazil. The design employed was randomized blocks, arranged in subdivided parcels and having three replications. The treatments consisted of five irrigation depths in the parcel and four potassium doses in the subparcel, totalizing 20 treatments. The five programmed irrigation depths were 50; 70; 90; 110 and 130% of the reference evapotranspiration and the four potassium doses were 30; 42; 54 and 66 g of K2O plant-1month-1. The high rainfall rates in the experimental period (February-2005 to June-2006), greatly overcame the plant water requirements, interfering in the treatments, not allowing significant variation in the variables analyzed, particularly in function of the applied depths. During the 11 months and 21 days of harvest, the average yield was 79.41 t ha-1, with an average of 96 fruits per plant which, in the first stage of ripening, presented a mass of 404 g, average total soluble solids content (SST) of 10.11 ºBrix and pulp and fruit firmness of 79.80 N and 126.19 N, respectively