Analysis of volatiles from feces of released Przewalski’s horse (Equus przewalskii) in Gasterophilus pecorum (Diptera: Gasterophilidae) spawning habitat

The absolute dominant species that infests wild population of Przewalski’s horse (Equus przewalskii) is Gasterophilus pecorum, and feces of released Przewalski’s horse, a habitat odor, plays an important role in mating and ovipositing locations of G. pecorum. To screen out unique volatiles for attracting G. pecorum, volatiles from fresh feces of released horses at stages of pre-oviposition (PREO), oviposition (OVIP), and post-oviposition (POSO) of G. pecorum, and feces with three different freshness states (i.e., Fresh, Semi-fresh, and Dry) at OVIP were collected by dynamic headspace adsorption and determined by automatic thermal desorption GC–MS. Results show that there were significant differences in fecal volatiles within both test conditions. Of the five most abundant volatiles from the five individual samples, the most important volatile was ammonium acetate at OVIP/Fresh, followed by acetophenone (Semi-fresh), toluene (PREO, OVIP and POSO), butanoic acid (OVIP and Semi-fresh), acetic acid (PREO, POSO and Semi-fresh), 1,6-octadiene,3,7-dimethyl-,(S)- (PREO, OVIP and POSO), 1,5,9-undecatriene,2,6,10-trimethyl-,(Z)- (PREO and Semi-fresh) and caprolactam (all conditions), which seem to be critical substances in oviposition process of G. pecorum. The findings may be beneficial to development of G. pecorum attractants, facilitating prevention and control of infection by G. pecorum to released Przewalski’s horse.

Classification of an equine skull in the Science Museum of Coimbra, Portugal, by means of multivariate and qualitative analysis

The study aimed at classifying an equine skull stored in Museu da Ciência da Universidade de Coimbra, Coimbra (Portugal) on the basis of its morphology using multivariate analyses. A visual appraisal had revealed that it was not from a horse. Nineteen cephalic measurements were obtained and compared with available data of horses of different groups (poneys, trait and saddle), equine hybrids, Przewalski’s horse (Equus przewalskii), wild and domestic asses, and quaggas (Equus quagga). Multivariate analysis plus head profile allowed us to assign the skull to a mare hinny -the hybrid between a jenny (female donkey) and a stallion (male horse). The research highlights the possibilities of categorization of equid skulls according to morphometry but with a need to consider qualitative traits, as head profiles. But more such studies are needed to be conducted to establish clearly differences between mules and hinnies, especially among sympatric populations.

Osudy koní Převalského (Equus przewalskii) importovaných z volné přírody (Perissodactyla: Equidae)

At the turn of the 19th and 20th centuries, 54 Przewalski’s horses were imported alive to Europe in five transports. Only twelve of them (6 ♂♂, 6 ♀♀) have bred. The earliest birth occurred in a mare at the age of five years and the oldest mare gave birth at the age of 17 years, always during the period from spring to autumn. The most fertile stallion was a father of ten foals and the most fertile mare gave birth to eight foals. Longevity was relatively high; three stallions reached the age over 20 years, the oldest one of 28 years. Cadavers of individuals imported from nature and registered in the pedigree-book are listed, they represent less than a half of all registered individuals officially imported to Europe.

The Double Rhythm Development and Characteristics of the Gasterophilus Pecorum (Diptera: Gasterophilidae) Population in Desert Steppe

Background: The departure of the mature larvae of the horse stomach bot fly from the host indicates the beginning of a new infection period, and the Gasterophilus pecorum becomes the dominant species in the desert steppe, showing its special biological characteristics. The population dynamics of G. pecorum were studied to reveal the population development rule of G. pecorum in the arid desert steppe. Method: The larvae were collected and recorded in the newly excreted feces by tracking the Przewalski’s horses (Equus przewalskii), meanwhile, the larval pupation experiments were carried out under natural conditions. Results: (a) There was a positive correlation between the survival rate and the number of larvae (r = 0.630, p < 0.01), indicating that the species development had the characteristics of centralized occurrence; (b) The main periods of mature larvae discharge were from early April to early May (peak Ⅰ) and from mid-August to early September (peak II), and the larval population curve showed a sudden spike in increase and gradual decrease at both peaks; under higher temperature, the number of adults from peak II had higher survival rate, higher pupation rate, higher emergence rate and less eclosion time than that of peak I; (c) Although it has one generation a year, the occurrence peak twice annually displaying a unique “ double rhythm development ” phenomenon, which forms a “ dual rhythm parasitism ” pressure on the local host. This phenomenon is very rare in the study of insect life history, especially in the parasite epidemiology. Conclusion: The natural discharge period of the G. pecorum larvae in Kalamaili Nature Reserve (KNR) is longer than 7 months and have the potentially long term infection effect on the host. The above phenomenon is one important reason for the local equine animals to be severely infected with equine myiasis.

Using nuclear microsatellite data to trace the gene flow and population structure in Czech horses

Based on a data set comprising 2879 animals and 17 nuclear microsatellite DNA markers, we propose the most comprehensive in-depth study mapping the genetic structure and specifying the assignment success rates in horse breeds at the Czech population scale. The STRUCTURE program was used to perform systematic Bayesian clustering via the Markov chain Monte Carlo estimation, enabling us to explain the population stratification and to identify genetic structure patterns within breeds worldwide. In total, 182 different alleles were found over all the populations and markers, with the mean number of 10.7 alleles per locus. The expected heterozygosity ranged from 0.459 (Friesian) to 0.775 (Welsh Part Bred), and the average level reached 0.721. The average observed heterozygosity corresponded to 0.709, with the highest value detected in the Czech Sport Pony (0.775). The largest number of private alleles was found in Equus przewalskii. The population inbreeding coefficient F_IS ranged from –0.08 in the Merens to 0.14 in the Belgian Warmblood. The total within-population inbreeding coefficient was estimated to be moderate. As expected, very large genetic differentiation and small gene flow were established between the Friesian and Equus przewalskii (F_ST= 0.37, Nm = 0.43). Zero F_ST values indicated no differences between the Czech Warmblood–Slovak Warmblood and the Czech Warmblood–Bavarian Warmblood. A high level of breeding and connectivity was revealed between the Slovak Warmblood–Bavarian Warmblood, Dutch Warmblood–Oldenburg Horse, Bavarian Warmblood–Dutch Warmblood, and Bavarian Warmblood–Oldenburg Horse. The breeds’ contribution equalled about 6% of the total genetic variability. The overall proportion of individuals correctly assigned to a population corresponded to 82.4%. The posterior Bayesian approach revealed a hierarchical dynamic genetic structure in four clusters (hot-blooded, warm-blooded, cold-blooded, and pony). While most of the populations were genetically distinct from each other and well-arranged with solid breed structures, some of the entire sets showed signs of admixture and/or fragmentation.