RESUMO
The importance of the protein ingestion during the adult stage on the mating success of males of Ceratitis capitata Wiedemann was evaluated in experiments of laboratory and field cage. In laboratory, the effects of protein ingestion during the first four or 12 days of the male adult life was assessed by the following parameters: mating success (capacity of being chosen by the female) and the number of males that give out pheromonal signals. Some experiments of mating success had been carried through with males in different ratios. In these tests, the number of males which had ingested protein (an unique male) was remained constant and the number of males fed without protein was gradually increased from 1:1 to 1:5. In the field cages, the mating success experiments were done using a 1:1 ratio. The results showed that the protein ingestion in the first four days of life did not influence any of the analyzed parameters. When the period of ingestion of protein was extended to 12 days, protein-fed males fed produced more pheromonal signals and had a higher mating success when at a 1:1 ratio in laboratory and field cage assays. In laboratory, females randomly chose males in any other tested ratio (1:2, 1:3, 1:4 and 1:5), indicating that the female may lose the perception to identify the male who ingested protein in the first 12 days.
Assuntos
Animais , Masculino , Ceratitis capitata , Proteínas Alimentares , Comportamento Sexual Animal/fisiologiaRESUMO
O objetivo deste estudo foi avaliar o efeito da senescência no sucesso de cópula e na secreção de feromônio sexual por machos de Ceratitis capitata (Wiedemann). O efeito do envelhecimento do macho sobre o acasalamento foi analisado utilizando-se machos com cinco e 21 dias de idade, através do seu sucesso de copula (escolha dos machos pela fêmea para cópula) e pela quantidade de machos que emitiram feromônio sexual. O sucesso de cópula foi avaliado através de várias proporções de machos jovens em relação a machos velhos pelo aumento do número de machos velhos:machos jovens de 1:1 até 5:1. O sucesso de cópula na proporção de 1:1 também foi avaliado em gaiola de campo. A avaliação do sucesso de cópula (na proporção 1:1) demonstrou clara preferência das fêmeas pelos machos jovens. A emissão de feromônio sexual foi mais comum em machos jovens do que em machos velhos. Mesmo em casos onde os machos velhos foram mais abundantes (proporções 2:1 e 3:1), as fêmeas continuaram escolhendo os machos jovens. Entretanto, as fêmeas não distinguiram mais os machos jovens em relação aos machos velhos nas proporções 4:1 ou 5:1. Os resultados indicam que o envelhecimento dos machos de C. capitata tem considerável efeito negativo sobre seu sucesso reprodutivo, especialmente se eles são encontrados em proporção menor do que 3:1.
The objective of this study was to evaluate the effect of male ageing on male pheromone release and mating success of Ceratitis capitata (Wiedemann). The effects of male ageing on mating were evaluated on five and 21 d-old males by assessing their mating success (males chosen by a female for copulation) and the amount of males releasing the sex pheromone. The mating success was evaluated by using several ratios of young to older males by increasing the number of older males:young males from 1:1 to 5:1. The mating success of the 1:1 ratio was also evaluated in field cages. The evaluation of the mating success (in the 1:1 ratio) showed a clear preference of the females for young males. Sex pheromone emission was much more common on young than older males. Even in cases were older males were more abundant (ratios 2:1 and 3:1), females still chose the young males. However, females could not distinguish young from older males in ratios of 4:1 or 5:1. Our data indicate that the ageing of C. capitata males has a considerable negative effect on their reproductive success, especially if they are found in a proportion any lower than 3:1.