Male coloration affects female gestation period and timing of fertilization in the guppy (Poecilia reticulata)

The trade-up hypothesis is a female behavioral strategy related to mating with multiple males. In this hypothesis, females can produce high-quality offspring while avoiding the risk of losing reproductive opportunities by non-selective mating with males at first mating and then re-mating with more attractive males. As an internal mechanism to realize this behavioral strategy, we predicted that females would immediately fertilize their eggs when they mated with attractive males, whereas females would delay fertilization when they mated with unattractive males to trade-up sires of offspring. The guppy (Poecilia reticulata) is an ovoviviparous fish with internal fertilization, and females show a clear mate preference based on the area of orange coloration on the bodies of males. In addition, it is known that females show a re-mating strategy consistent with the trade-up hypothesis. We tested whether the attractiveness of mated males affected the gestation period and the timing of fertilization. Females were paired with either colorful males or drab males, and the gestation periods (the number of days from mating to parturition) were compared. In addition, we dissected the abdomens of the females at intervals of several days after mating and observed whether the eggs were fertilized. The gestation period in females that were paired with attractive colorful males was significantly shorter than that in females that were paired with drab males. We found that females that mated with colorful males also had their eggs fertilized earlier than those that mated with drab males. Our findings show that differences in the timing of fertilization according to attractiveness of the mate increase the opportunity for cryptic female choice and trading up.

237 Evaluation of fleece and fiber characteristics of ultrafine Paco-Vicunas farmed in Missouri

Data recordings of animal breeding, fleece production, and fiber characteristics in an ultrafine Paco-Vicuna herd farmed at Victory Farm, Missouri were analyzed. A selective mating strategy was applied while establishing an ultrafine fleece growing Paco-Vicuna herd on the ranch over 12 years. The herd size was expanded from five males and one dozen breeding females in 2009 to more than 200 heads in 2016. All animals were recorded for sires, dams, and registered pedigree, birth weight, weaning weight, shearing weight, and fleece weight. Mid-side flank fleece samples were measured for Optical Fiber Diameter Analyser (OFDA) fiber characteristics, including mean fiber diameter, length, and fiber curvature. Live weight, fleece weight, and fiber characteristics were analyzed using SAS® GLM procedures. Mean birth weight, weaning weight, mixed age shearing weight, fleece weight, fiber diameter, coefficient of fiber diameter variation, fiber length, and fiber curvature were 6.82 kg, 25.27 kg, 48.84 kg, 0.85 kg, 16.6 µm, 25.2%, 64.6 mm and 56.9 degree /mm, respectively. The average fiber diameter of herd was 18.3 µm at 2009 clip, which was gradually but significantly (P < 0.05) reduced yearly to 16.4 µm at 2019 clip. In addition, the finest 25 percent of the herd’s fleeces were tested and found to have an average fiber diameter of 14 micron, which was within vicuna fleece fiber diameter ranges. These measures did not significantly increase with ages. Heritability estimates for the fleece weight and fiber diameter, length, and curvature were 0.40, 0.65, 0.29, and 0.50, respectively. The average fiber diameter measurements of Paco-Vicuna herd at Victory Farm were significantly (P < 0.01) finer than the comparable camelid herds in the country. This study found that strict selective breeding is effective for genetic gains in ultrafine fiber diameter and fleece quality in Paco-Vicunas.

Genetic Divergence of the Species of the Yellow Wagtails Group (Passeriformes, Motacillidae) in European Territory of Russia

Phenotypic and genotypic diversity of populations of species of the yellow wagtails in the space of their ranges in a wide sympatry reflects the mechanisms of reproductive isolation of species and forms of subspecies rank and features of microevolution group - polytypic complex Motacilla flava Linnaeus, 1758. The distribution of species of the yellow wagtails in the European part of Russia is sympatric. The purpose of this study was to investigate whether sympatric settlement led to any genetic separation between the populations of these species. 20 blood samples and 2 samples of eggs collected in areas geographically representing the MID and the southern Russian breeding populations of these species, including all juvenile ringed in 2012, were used. After the polymerase chain reaction (PCR) 4 types of the yellow wagtails group Motacilla flava L., 1758; M. feldegg Michahelles, 1830; M. lutea (S. G. Gmelin, 1774); M. cilreola Pallas, 1776 (Passeriformes, Motacillidae) were sequenced. After aligning the sequences of the gene cytochrome oxidase I, based on the comparison of genetic distances between these species phylogenetic tree of genus Motacilla was constructed. These results suggest that, despite the broad sympatry in nesting places, there is a selective mating between males and females of each species studied in spite of the free crossing and insulating mechanisms in populations.

ROLE OF SELECTIVE MATING IN POPULATION SPLITTING

We present a simple model of pseudo-speciation driven only by selective mating. Using Monte Carlo simulation on a lattice we show that even without considering the genetic structure of the individuals a population living in a homogeneous habitat will divide into two, spatially separated, groups having different values of their trait. After some time one group (species) will change their trait and will be absorbed into the winning species.