Direct glia-to-neuron transdifferentiation gives rise to a pair of male-specific neurons that ensure nimble male mating

Sexually dimorphic behaviours require underlying differences in the nervous system between males and females. The extent to which nervous systems are sexually dimorphic and the cellular and molecular mechanisms that regulate these differences are only beginning to be understood. We reveal here a novel mechanism by which male-specific neurons are generated in Caenorhabditis elegans through the direct transdifferentiation of sex-shared glial cells. This glia-to-neuron cell fate switch occurs during male sexual maturation under the cell-autonomous control of the sex-determination pathway. We show that the neurons generated are cholinergic, peptidergic, and ciliated putative proprioceptors which integrate into male-specific circuits for copulation. These neurons ensure coordinated backward movement along the mate’s body during mating. One step of the mating sequence regulated by these neurons is an alternative readjustment movement performed when intromission becomes difficult to achieve. Our findings reveal programmed transdifferentiation as a developmental mechanism underlying flexibility in innate behaviour.

The complex communication signals in the mating behavior of the tropical cricket Cranistus colliurides Stål, 1861 (Orthoptera: Grylloidea; Trigonidiidae: Phylloscyrtini)

Cricket mating behavior reflects different strategies developed by sexual selection throughout evolutionary time. To our knowledge, only one species of the Neotropical cricket Trigonidiinae had its mating behavior studied so far. Here we expand this knowledge by describing the mating behavior of Cranistus colliurides Stål, 1861, a cricket commonly found in bushes and grasses along open fields or the forest edge. Adult crickets were collected in the municipality of Capão do Leão, State of Rio Grande do Sul, Brazil. Trials were carried out in laboratory to characterize the mating sequence. We quantified elapsed time of each behavioral sequence and discussed its implications in the observed mating behavior. The males of C. colliurides attracted females by means of a continuous trill, and receptive female triggers the beginning of the courtship through antennation. During courtship, copulation and post-copulatory actions, males showed a complex communication system based on information send to female by substrate vibration and an elaborated repertoire composed by calling, courtship and post-copulatory song. The mating behavior here described reveals divergence between related species hitherto studied which give us clues to understand how the sexual selection shaped the complex behaviors exhibited by Trigonidiinae crickets presently.

Despite reproductive interference, the net outcome of reproductive interactions among spider mite species is not necessarily costly

This preprint has been reviewed and recommended by Peer Community in Evolutionary Biology (http://dx.doi.org/10.24072/pci.evolbiol.100025). Reproductive interference is considered a strong ecological force, potentially leading to species exclusion. This supposes that the net effect of reproductive interactions is strongly negative for one of the species involved. Testing this requires a comprehensive analysis of interspecific reproductive interactions, accounting for the order and timing of mating events, and for their effects on either fertility or fecundity. To this aim, we measured reproductive interactions between a focal species, Tetranychus urticae, and an invasive (T.evansi) and a resident (T. ludeni) species, varying the mating sequence and interval, and measuring the effect of such crosses on fecundity and offspring sex ratio (a measure of fertility, as these species are haplodiploid). We found that mating with heterospecifics affected fecundity and sex ratio negatively, but also positively, depending on the species involved, and on the order and timing of mating events. Overall, the net effect of reproductive interactions was weak despite strong effects of particular events. In natural situations, the outcome of reproductive interactions will thus hinge upon the frequency of each event.

Complex mating behavior in Adelosgryllus rubricephalus (Orthoptera, Phalangopsidae, Grylloidea)

We describe the mating behavior of Adelosgryllus rubricephalus Mesa & Zefa, 2004. In trials carried out in laboratory we verified the following mating sequence: (1) sexual recognition by antennation; (2) courtship with male turning his abdomen towards the female, performing mediolateral antennae vibration, jerking its body antero-posteriorly and stridulating intermittently, while receptive female drums on the male's abdomen tip, cerci and hind-tibia with her palpi or foretarsi; the male then stops and stays motionless for some seconds, extrudes the spermatophore and both restart the behavioral sequence described above; (3) copulation: male underneath female; with his tegmina inclined forward, and joins his genitalia to the female's to promote sperm transference ; the female steps off the male, occurring a brief end-to-end position; (4) postcopulation: without guarding behavior; male retains the spermatophore and eats it. We quantified elapsed time of each behavioral sequence and discussed its implications in the observed mating behavior.

Courtship and mating behaviour of the Mediterranean corn borer, Sesamia nonagrioides (Lepidoptera: Noctuidae)

The behavioural sequence of courtship and mating of Sesamia nonagrioides Lefèbvre males and females in laboratorycages is described. The attractant capacity of both sexes was studied by tethering males or females. The courtshipand mating sequence of tethered females was the same as untethered ones, but tethered males were absolutely inactive.Age (1 day versus 2 days) did not affect the mating rate. Differences in calling time onset and first calling agewere found between north-eastern Spanish and Greek populations. The role of hair pencils in courtship flight is discussed,rejecting that they stimulate calling behaviour of females or that they attract females. The influence of adultpopulation density was studied in laboratory and field tests, and was found to have no effect on the mating rate in thecontrols. However, moth density influenced mating rates where mating disruption treatments were applied. Several consequences for investigations into pheromone composition and its use in monitoring and population control are reported in the discussion.

Observations on an apparent mating sequence in three Southern Right Whales, Eubalaena australis (Cetacea: Balaenidae).

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Courtship and copulation in the terrestrial snail Helix aspersa

Mating behaviour in Helix aspersa has three major components: introductory behaviour, dart shooting, and copulation. Introductory behaviour, which includes reciprocal tactile and oral contacts, lasts an average of 33.7 ± 23.3 (SD) min. Dart shooting, the pushing of a calcareous dart into the mating partner's body, occurs once for each snail per mating sequence. Snails that hit their partners during the first dart-shooting event copulated 14.5 ± 8.7 min after dart shooting, whereas snails that missed their partners took 40.5 ± 37.5 min to copulate. Dart shooting may facilitate mating by increasing behavioural synchrony. Copulation is reciprocal and has a duration of 421.8 ± 56.6 min. Spermatophores are transferred approximately 300 min after simultaneous intromission. There are significant differences in the mating behaviours of Helix aspersa and Helix pomatia.