SPIDER DEAD-ENDS. “In the short term, inbreeding is expected to result in the expression of recessive deleterious alleles with the consequent reduction in fitness (i.e., inbreeding depression) of the offspring of close relatives. Further, even after the most damaging recessive deleterious alleles have been removed from a population due to repeated cycles of inbreeding, inbred individuals are expected to suffer from reduced fitness due to loss of heterosis.”
https://www.researchgate.net/profile/Leticia_Aviles/publication/259116856_The_Evolution_of_Inbred_Social_Systems_in_Spiders_and_Other_Organisms_From_Short-Term_Gains_to_Long-Term_Evolutionary_Dead_Ends/links/00b4952a0304203a9d000000.pdf