More to legs than meets the eye:Presence and function of pheromone compounds on heliothine moth legs

Chemical communication is ubiquitous in nature and chemical signals convey species‐specific messages. Despite their specificity, chemical signals may not be limited to only one function. Identifying alternative functions of chemical signals is key to understanding how chemical communication systems evolve. Here, we explored alternative functions of moth sex pheromone compounds. These chemicals are generally produced in, and emitted from, dedicated sex pheromone glands, but some have recently also been found on the insects' legs. We identified and quantified the chemicals in leg extracts of the three heliothine moth species Chloridea (Heliothis) virescens, Chloridea (Heliothis) subflexa and Helicoverpa armigera, compared their chemical profiles and explored the biological function of pheromone compounds on moth legs. Identical pheromone compounds were present on the legs in both sexes of all three species, with no striking interspecies or intersex differences. Surprisingly, we also found pheromone‐related acetate esters in leg extracts of species that lack acetate esters in their female sex pheromone. When we assessed gene expression levels in the leg tissue, we found known and putative pheromone‐biosynthesis genes expressed, which suggests that moth legs may be additional sites of pheromone production. To determine possible additional roles of the pheromone compounds on legs, we explored whether these may act as oviposition‐deterring signals, which does not seem to be the case. However, when we tested whether these chemicals have antimicrobial properties, we found that two pheromone compounds (16:Ald and 16:OH) reduce bacterial growth. Such an additional function of previously identified pheromone compounds likely coincides with additional selection pressures and, thus, should be considered in scenarios on the evolution of these signals

Desempenho de novilhos em crescimento em pastagem de Brachiaria decumbens suplementados com diferentes fontes energéticas no período da seca e transição seca-águas Development of growing steers on Brachiaria decumbens supplemented with different energy sources during the dry season and transition from dry to wet season

Objetivou-se, neste trabalho, estudar o efeito da suplementação, com diferentes fontes energéticas, sobre o desempenho de novilhos em crescimento e a viabilidade econômica da suplementação, bem como avaliar a disponibilidade e composição química da braquiária (Brachiaria decumbens Stapf), no período de julho a novembro, na região Oeste do Estado de São Paulo. Foram utilizados 42 novilhos da raça Nelore, distribuídos em três piquetes de 7,2 ha cada. As fontes energéticas utilizadas como suplementos foram: milho desintegrado com palha e sabugo (MDPS), farinha de mandioca de varredura (FMV) e casca do grão de soja (CGS). Todos os tratamentos continham farelo de algodão, para atingir 25% de PB, e foram fornecidos em nível de 1,3% do PV. As pesagens dos animais foram realizadas a cada 14 dias e a disponibilidade de forragem foi estimada a cada 28 dias. A disponibilidade média de forragem foi de 2.570 kg de MS/ha e 1.306 kg de lâmina foliar/ha. A proporção de lâmina foliar apresentou comportamento quadrático em função do período experimental, com valor mínimo de 46,58%, observado em agosto. Os teores médios de proteína bruta foram de: 4,45% para planta inteira; 5,30% para lâmina foliar e 2,83% para o colmo + bainha. Os teores médios de FDN e FDA foram, respectivamente, de 70,61% e 39,93% para a planta inteira; 65,76% e 34,91% para a lâmina foliar e 75,83% e 47,90% para o colmo + bainha. Entre os suplementos não houve diferença para ganho médio diário, apresentando média de 0,836 kg/animal/dia. O suplemento mais viável economicamente foi o que continha a farinha de mandioca de varredura, pois, além de apresentar menor custo, foi o que proporcionou maior ganho animal, mostrando melhor relação receita: custo.<br>The aim of this work was evaluate the effect of supplementation with different energetic sources, on growing steers performance and economical viability, and also evaluate the structure and chemical composition of Signalgrass (Brachiaria decumbens) from July to November, on São Paulo state west region. Forty-two animals (Nelore) and three pastures of 7.2 ha each, were used. The energy sources used for supplements were: corn and cob with husks (CCH), cassava meal (CM) and soybean hulls (SH); each treatment had cottonseed meal to reach 25% of CP, and was given at 1.30% of BW. The animal weight was verified at each 14 days and forage characteristics were evaluated at each 28 days. The average availability of forage was 2570 kg DM/ha and 1306 kg leaves/ha. Leaves proportion showed a quadratic behavior in function of experimental period, with minimum value of 46.58 % observed in August. The average levels of CP were 4.45% for all plant, 5.30% for leaf e 2.83% for steam. The average levels of NDF and ADF were, respectively 70.61% and 39.93% for all plant, 65.76% and 34.91% for leaf, and 75.83% and 47.90% for steam. The supplements were not different on average daily gain, with average of 0.836 kg/animal/day. The supplement more economically viable was the cassava meal, which showed lesser coasts and bigger animal gain with better relation income:costs