Morphogenetic Consequences of Short-Term Thermal Stress in Short and Long Life House Fly Lines (Musca Domestica L.): Geometric Wing Morphometrics

The morphogenetic consequences of exposure to short-term heat stress (STHS) in two housefly strains mass-selected for lifespan were studied based on the assessment of adult wing variability by geometric morphometrics. Significant differences in the size and shape of the wing between the control and impact groups of different genders in the strains were revealed. Shg (short lived) and Lg (long-lived). The STHS effect manifested in an increase in the size of the wing and a directed change in its shape. The between-group hierarchy of gender and stress-induced differences is expressed in the same way in both strains of flies. The range of linear differences is significantly higher than the gender differences, which, in turn, are higher than the level of stress-induced ones. Instability of imago wing development ( Vm ) in Shg was significantly higher than the Lg strains, and higher in all groups of females, but in most cases significantly lower in impact groups (taking into account the increase in size, the latter may be associated with the effect of hormesis). It is hypothesized that the directed morphogenetic effects of STHS are based on latent species modifications, the appearance of which in the phenotype is due to stress-induced epigenetic genome rearrangements that cause similar morphological changes in the wing in groups of adult males and females of both strains. The phenotypic plasticity of strains during selection for different lifespans and the changes induced by STHS directly indicate the reality of stress-induced rapid morphogenetic rearrangements under a sharp change in environmental conditions.