Age-dependent insemination success of sterile Mediterranean fruit flies

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Is polyandry a common event among wild populations of the pest Ceratitis capitata?

In many insect species, females can mate more than once and store sperm from more than one male. An assessment and understanding of polyandry in the field can be important for pest species with a high colonization potential, such as the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), which is also highly polyphagous and among the most destructive agricultural insects. The use of polymorphic microsatellite markers, combined with different statistical approaches, provides evidence that polyandry occurs in two C. capitata natural populations, one population from the Greek island of Chios and one population from Rehovot, in Israel. The observed different level of polyandry is discussed in relation to the genetic diversity, seasonality, and demography of the two populations. When polyandry is present, paternity analysis also indicates that one male, presumably the last, tends to sire most of the progeny. Polyandry and paternity skew may have important implications for the evolution of the species, in terms of maintenance of the genetic variability. Moreover, these aspects of the mating behavior, i.e., remating frequency and paternity skew, may locally affect the sterile insect technique, the most commonly applied control strategy against C. capitata

Polygyny in the olive fly-effects on male and female fitness

Polygynous males must balance their limited ejaculate resources between current copulations, with putative future ones. Working on olive flies (Bactrocera oleae), our objectives were to determine (a) how males budget sperm to consecutive copulations, (b) what costs consecutive copulations incur, and (c) how male mating history affects female fecundity, fertility, and longevity. We allowed males to copulate with virgin females on successive days and monitored the fertility and fecundity of these females, and the longevity of both sexes. We found that as males gained sexual experience, latency to mate declined significantly, while copula duration increased. The number of sperm stored by females declined according to the sexual history of her mate-as males gained experience, significantly fewer sperm cells were transferred. Mated males suffered a significant longevity cost compared to virgin ones, but this cost was not compounded by additional matings. Male sexual experience affected both female fecundity and fertility. Furthermore, mating with an experienced male incurred a longevity cost to females. We conclude that non-sperm components of the male ejaculate are responsible for reducing female fecundity, fertility, and longevity, and predict that females should prefer to mate with virgin males

Transcriptome profiling of sexual maturation and mating in the Mediterranean fruit fly, Ceratitis capitata

Sexual maturation and mating in insects are generally accompanied by major physiological and behavioural changes. Many of these changes are related to the need to locate a mate and subsequently, in the case of females, to switch from mate searching to oviposition behaviour. The prodigious reproductive capacity of the Mediterranean fruit fly, Ceratitis capitata, is one of the factors that has led to its success as an invasive pest species. To identify the molecular changes related to maturation and mating status in male and female medfly, a microarray-based gene expression approach was used to compare the head transcriptomes of sexually immature, mature virgin, and mated individuals. Attention was focused on the changes in abundance of transcripts related to reproduction, behaviour, sensory perception of chemical stimulus, and immune system processes. Broad transcriptional changes were recorded during female maturation, while post-mating transcriptional changes in females were, by contrast, modest. In male medfly, transcriptional changes were consistent both during maturation and as a consequence of mating. Of particular note was the lack of the mating-induced immune responses that have been recorded for Drosophila melanogaster, that may be due to the different reproductive strategies of these species. This study, in addition to increasing our understanding of the molecular machinery behind maturation and mating in the medfly, has identified important gene targets that might be useful in the future management of this pest