1,722,195 research outputs found
Nuptial food gifts influence female egg production in the scorpionfly Panorpa cognata
Full text linkEngqvist L. Nuptial food gifts influence female egg production in the scorpionfly Panorpa cognata. Ecological Entomology. 2007;32(3):327-332.1. Before copulation, male Panorpa cognata scorpionflies offer females a salivary secretion, which is consumed by the female during copulation. It has previously been demonstrated that this nuptial food gift functions as mating effort by increasing male attractiveness and by increasing ejaculate transfer during copulation.
2. In this study, the effect of saliva consumption on female reproductive output was investigated, and thus the possibility that nuptial food gifts also serve as paternal investment. The experimental design enabled the effect of nuptial gift consumption to be disentangled from other possible effects of multiple mating or increased copula duration.
3. The results showed that saliva consumption increases female egg production by on average 8% (4.5 eggs) per consumed salivary mass, whereas mean egg weight was not influenced.
4. These results have important implications for the evolution and maintenance of both male nuptial gifts and female polyandry in this and other species
Should I stay or should I go? Condition- and status-dependent courtship decisions in the scorpionfly Panorpa cognata
Full text linkEngqvist L. Should I stay or should I go? Condition- and status-dependent courtship decisions in the scorpionfly Panorpa cognata. Animal Behaviour. 2009;78(2):491-497.The occurrence of prolonged courtship behaviour in many animal species is a well-known phenomenon. The duration of courtship may be influenced by both females and males, often with different interests. In the scorpionfly Panorpa cognata, males offer a salivary secretion as a nuptial gift before copulation. However, males do not immediately initiate copulation by the production of the salivary mass. Instead pairs usually engage in prolonged courtship interactions. Yet the duration of courtship is highly variable, ranging between a few minutes and several hours. Furthermore, courtship does not always result in copulation; instead females often terminate courtship and abandon the male. The duration and outcome of courtship are likely to be influenced by factors such as body condition and female mating history, because they might influence individual attractiveness and motivation to mate. I examined to what extent these factors influence both male and female courtship decisions. Mated females were less keen to remain in courtship for long and abandoned males sooner than virgin females. Yet, male mating behaviour was unaffected by female mating status. Counterintuitively, females in poor condition interrupted courtship sooner with increasing body weight of their male partner. In addition, heavier males initiated copulations sooner than males in poorer condition. However, this effect was evident only in interactions with females in poor condition. A possible interpretation of these results is that males attempt to prevent females in poor condition from leaving prior to copulation by initiating copulation faster
Females benefit from mating with different males in the scorpionfly Panorpa cognata
Full text linkThe adaptive significance of female polyandry has become a recurrent subject of recent theoretical and empirical research. It has been argued that in addition to direct benefits, such as nuptial gifts or an adequate sperm supply, females may gain genetic benefits from mating with different males. Females of the scorpionfly Panorpa cognata mate with several males during their lifetime. In an experiment designed to rule out any direct nutritional benefit of multiple matings, I found that polyandrous females that mated with two different males achieved a significantly higher egg-hatching success than monandrous females that mated twice with the same male. However, individual males did not trigger the same response in different females as the egg-hatching success of different females that mated with one and same male did not correlate. The results, thus, do not conform to predictions from hypotheses assuming that genetic benefits of polyandry are influenced by the intrinsic genetic quality of males. The results are, however, consistent with the genetic incompatibility hypothesis. Nevertheless, substances from different males transferred during copulation may synergistically affect zygote viability. Furthermore, I discuss why paternity studies can only explicitly test the genetic incompatibility hypothesis if there are a priori expectations of female-male genome compatibilities. Copyright 2006.egg-hatching success; genetic incompatibility; Mecoptera; polyandry; sperm limitation
Sperm transfer and paternity in the scorpionfly Panorpa cognata: large variance in traits favoured by postcopulatory episodes of sexual selection
Full text linkEngqvist L, Dekomien G, Lippmann T, Epplen JT, Sauer KP. Sperm transfer and paternity in the scorpionfly Panorpa cognata: large variance in traits favoured by postcopulatory episodes of sexual selection. Evolutionary Ecology. 2007;21(6):801-816.Post-copulatory episodes of sexual selection can be a powerful selective force influencing the reproductive success of males. In order to understand variation in male fertilisation success, we first need to consider the pattern of sperm utilisation by females following matings with more than one male. Second, we need to study those traits responsible for male success in sperm competition. Here we study both male sperm transfer characteristics as well as offspring paternity of females mated to two males in the scorpionfly Panorpa cognata. By repeatedly mating males to virgin females and interrupting copulation at defined time points, we found for all males that sperm transfer set off after approximately 40 min. During the remaining copulation, sperm transfer of individual males was continuous and with constant rate. Yet the rate of sperm transfer differed between individual males from about one sperm per minute to more than eight sperm per minute for the most successful males. In addition, we measured the fertilisation success in sperm competition of males with known sperm transfer capability. The relative number of sperm transferred by males during copulation, estimated from copulation duration and the males' individual sperm transfer rate, explained a large proportion of variation in offspring paternity. The mode of sperm competition in this species, thus, conforms largely to a fair raffle following complete mixing of sperm prior to fertilisation. Hence, male differences in both the ability to copulate for long and of rapid sperm transfer will translate directly into differences in reproductive success
Carex cognata var. cognata (10667)
No full textKingdom: PlantaeDivision: MagnoliophytaClass: MonocotsOrder: PoalesFamily: CyperaceaeScientific name: Carex cognata var. cognata KunthSpecimen barcode: 1066
Determinants of sperm transfer in the scorpionfly Panorpa cognata: male variation, female condition and copulation duration
Full text linkEngqvist L, Sauer KP. Determinants of sperm transfer in the scorpionfly Panorpa cognata: male variation, female condition and copulation duration. Journal of Evolutionary Biology. 2003;16(6):1196-1204.Recent studies suggest that sperm production and transfer may have significant costs to males. Male sperm investment into a current copulation may therefore influence resources available for future matings, which selects for male strategic mating investment. In addition, females may also benefit from actively or passively altering the number of sperm transferred by males. In the scorpionfly Panorpa cognata, the number of sperm transferred during copulation depended on copulation duration and males in good condition (residual weight) copulated longer and also transferred more sperm. Moreover, sperm transferred and stored per unit time was higher in copulations with females in good condition than in copulations with females in poor condition. Males varied greatly and consistently in their sperm transfer rate, indicative of costs associated with this trait. The duration of the pairing prelude also varied between males and correlated negatively with the male's sperm transfer rate, but no other male character correlated significantly with male sperm transfer rate. The results are consistent with strategic mating effort but sperm transfer could also be facilitated by the physical size of females and/or females in good condition may be more cooperative during sperm transfer
cognata
No full textDigitaria cognata (Schultes) Pilgerfall crabgrassdigitaire d'automneLeptoloma cognataHatfieldsandy fiel
Male scorpionflies assess the amount of rival sperm transferred by females' previous mates
Full text linkEngqvist L. Male scorpionflies assess the amount of rival sperm transferred by females' previous mates. Evolution. 2007;61(6):1489-1494.Theory predicts that when sperm compete numerically, selection will favor males who vary the number of sperm they transfer with the immediate level of sperm competition. In this study, I measured male mating investment in response to both female mating status (virgin vs. mated) and the number of foreign sperm stored by females in a previous mating in the scorpionfly Panorpa cognata. Female sperm storage was manipulated by interrupting copulations at different time points. Female mating status did not significantly influence male mating investment, but resource-limited males invested strategically in relation to the amount of sperm stored by females in a previous mating. I found continuously decreasing male investment in response to increasing amounts of competing sperm. These results demonstrate an unprecedented male ability to assess the number of sperm stored by females. As a result, males are capable of an extraordinarily fine-tuned reaction to the intensity of sperm competition
Genetic variance and genotype reaction norms in response to larval food manipulation for a trait important in scorpionfly sperm competition.
Full text linkEngqvist L. Genetic variance and genotype reaction norms in response to larval food manipulation for a trait important in scorpionfly sperm competition. Functional Ecology. 2008;22(1):070915213639001-???Sperm competition is an important attribute of many mating systems. Examining the genetic and environmental factors influencing male sperm competition success is essential in order to understand variation in reproductive success.
In the scorpionfly Panorpa cognata, male success in sperm competition is influenced by the number of sperm transferred during copulation. This will be determined by copulation duration and the sperm transfer rate of males. Sperm transfer rate is a trait which shows considerable phenotypic variance.
Here, I use a full-sib split-brood design in order to investigate both to what extent this trait is heritable and the influence of larval food availability on male sperm transfer rate.
The results demonstrate considerable genetic variance underlying the phenotypic expression of sperm transfer rate. Heritability estimates were slightly larger, but not significantly so, for offspring reared at low food availability.
In contrast, there was no straightforward evidence that larval food availability had an effect on the sperm transfer rate of males. However, a significant family x treatment interaction provided evidence of a genotype x environment effect on male sperm competitive ability. These results demonstrate different reaction norms for sperm transfer rate in response to larval treatment for individuals with different genetic background
Braunsomeria cognata TURNER 1920
No full textBraunsomeria cognata TURNER 1920 Braunsomeria cognata TURNER 1920: 490. Lectotypus (here designated in order to ensure the name’ proper and consistent use). South Africa: /Junction Crocodile Marico R. Transvaal/ / Braunsomeria cognata Turn. Type / (autographic) /Type/ (red) /SAM HYM A00 3082/, SAM! Pal 2- and Pam 4-segmented.Published as part of Boni, M., 2011, Myzininae of the Old World The subtribe Braunsomeriina (Hymenoptera: Tiphiidae), pp. 363-380 in Linzer biologische Beiträge 43 (1) on page 375, DOI: 10.5281/zenodo.532459
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