Body Remains Left by Bird Predators as a Reliable Source for Population Genetic Studies in the Great Capricorn Beetle Cerambyx cerdo, a Veteran Oak Specialist

Abstract

Obtaining biological material for DNA extraction is often challenging in organisms of conservation interest. Non-invasive sampling (i.e., sampling without injuring or disturbing an animal) is preferred as it carries no risk to the population’s survival. Here, we tested the possibility of using the body remains left by bird predators for microsatellite genotyping in Cerambyx cerdo, a veteran oak specialist. We compared results obtained from such potentially degraded samples with samples of fresh beetle tarsi (i.e., invasive and destructive but non-lethal samples). Using 10 SSR loci, we genotyped 28 fresh, and 28 remains samples. The analysis indicated that PCR amplification efficiency was not influenced by sample type but allele length and individual heterozygosity. Allele frequencies were perfectly correlated for both sample types (R2 = 0.94). Additionally, null allele frequencies and genotyping failure rates were not significantly different from zero. Although the point estimates of individual inbreeding rates (fi) were higher in remains than fresh samples (medians 0.08 vs. 0.02, respectively), both groups were not significantly different from each other and zero. Our study demonstrated that non-invasive remains samples could provide satisfactory data for population–genetic studies. However, we highlight the problem of biased inbreeding estimates, which may result from samples affected by allelic dropout.

Female delayed mating has a limited impact on the reproductive output of Cerambyx welensii, a synovigenic longhorn beetle

“…It follows that under field conditions, the impact of delayed mating on female fitness would be critical if the female dies young due to stress/damage derived from constant male harassment, early predation or poor nutrition. For instance, adult predation by birds (Ceia & Ramos, 2016; Redlarski et al, 2021; Strojny, 1977) and meso‐mammals (Torres‐Vila, López‐Calvo, et al, 2017) may be intense, and the lack of adult feeding sources may be critical in extreme summers, especially in Mediterranean habitats (Torres‐Vila, 2024). Second, the daily fecundity pattern largely depended on female age at mating, with a great increase in the egg‐laying rate taking place in the day(s) following delayed mating, similar to that reported in the beetle A. orientalis (Wenninger & Averill, 2006).…”

Genetic diversity and population structure of the endangered saproxylic beetle L. cervus in a fragmented landscape

“…Non‐invasive sampling was performed during June–September 2022. We collected fragments of the beetles' bodies left behind by predators, which are a good source of material for population genetic analyses (Redlarski et al, 2021). In alignment with the granted permission, a total of 250 dead L. cervus specimens or fragments were collected, of which 118, 17 and 15 individuals from sites 1–3, respectively, were subjected to the final genetic analysis.…”