Genetic diversity of a flightless dung beetle appears unaffected by wildfire

The wildfires of Australia’s Black Summer in 2019/2020 caused a massive loss of wildlife and habitats, but the effects of the fire on invertebrate species post-burn are unknown. We hypothesised that the fires would negatively affect the genetic diversity of invertebrate species by impeding movement between populations due to habitat loss. We studied the genetic diversity of a flightless dung beetle, Amphistomus primonactus Matthews 1974, to determine the impact of the wildfires on this species. We examined 90 SNPs from 193 individuals across seven localities impacted by the wildfires in north-eastern New South Wales. We used STRUCTURE to determine the overall population structure of the seven localities. We calculated four within-locality genetic diversity measures (observed heterozygosity (Ho), unbiased expected heterozygosity (uHe), Shannon’s Information (1 H), and the inbreeding coefficient (FIS). We calculated three between-locality genetic diversity measures (Fixation Index (FST), Hedrick’s G”ST, and Shannon’s Mutual Information (I). We used partial Mantel tests to compare the between-locality genetic diversity measures with the mean fire intensity along each pairwise linear transect, while accounting for genetic variation due to geographic distance. We compared the within-locality genetic diversity measures to the mean fire intensity at each site. STRUCTURE showed a large degree of intermixing between localities. We found no significant effect of fire on any within-locality genetic diversity measure, or on any between-locality genetic diversity measure. We suggest that the genetic diversity of A. primonactus was not significantly affected by the Black Summer wildfires. Implications for insect conservation: Our results show that the 2019/2020 wildfires had a negligible impact on the genetic structure of A. primonactus. This offers a promising outlook for the species in its recovery from the fires

Parental breeding age effects on descendants' longevity interact over 2 generations in matrilines and patrilines

Individuals within populations vary enormously in mortality risk and longevity, but the causes of this variation remain poorly understood. A potentially important and phylogenetically widespread source of such variation is maternal age at breeding, which typically has negative effects on offspring longevity. Here, we show that paternal age can affect offspring longevity as strongly as maternal age does and that breeding age effects can interact over 2 generations in both matrilines and patrilines. We manipulated maternal and paternal ages at breeding over 2 generations in the neriid fly Telostylinus angusticollis. To determine whether breeding age effects can be modulated by the environment, we also manipulated larval diet and male competitive environment in the first generation. We found separate and interactive effects of parental and grand-parental ages at breeding on descendants' mortality rate and life span in both matrilines and patrilines. These breeding age effects were not modulated by grand-parental larval diet quality or competitive environment. Our findings suggest that variation in maternal and paternal ages at breeding could contribute substantially to intrapopulation variation in mortality and longevity