Brood Failure dataBrood failure of Nicorphorus vespilloides females on mouse carcasses aged for seven days and on fresh carcasses, collected for Experiment 1 in the linked publication. ‘History’ refers to the mother’s natal environment, ‘Treatment’ to the carcass provided for her first breeding attempt. The weight of the female beetle (‘Mother_weight’) and the mouse carcass (pre-aging) (‘Mouse_weight’) are given. Brood size refers to the number of successfully dispersing offspring.Dryad JEB_12394 Brood Failure data csv.csvBrood weight data – Experiment 1Brood size and weight produced by Nicorphorus vespilloides females on mouse carcasses aged for seven days and on fresh carcasses, collected for Experiment 1 in the linked publication. ‘History’ refers to the mother’s natal environment, ‘Treatment’ to the carcass provided for her first breeding attempt. ‘Family’ indicates which sister females were mated to the same male. The weight of the female beetle (‘Mother_weight’) and the mouse carcass (pre-aging) (‘Mouse_weight’) are given. Brood size refers to the number of successfully dispersing offspring.Dryad JEB_12394 Egg data csv.csvBrood weight data – Experiment 3Brood size and weight of cross-fostered Nicorphorus vespilloides broods, collected for Experiment 3 in the linked publication. The foster mother prepared the mouse carcass and provided post-hatch care. ‘Foster_mother history’ and ‘Genetic_mother history’ refer to the environment which the breeding females experienced as larvae. The weights of the foster mother and of the mouse carcasses (which were fresh in all cases) are given. The cross-fostered broods all consisted initially of 20 larvae (‘Start_number_larvae’). Survival and brood weight were then recorded at 24 hours and at dispersal.Dryad JEB_12394 Expt 3 data csv.csvEgg data – Experiment 2Average volume and number of eggs produced by Nicorphorus vespilloides females on mouse carcasses aged for seven days and on fresh carcasses, collected for Experiment 2 in the linked publication. ‘History’ refers to the mother’s natal environment. The weight of the female beetle (‘Mother_weight’) is also given.Dryad JEB_12394 Egg data csv.csv

Intergenerational effects can have either adaptive or nonadaptive impacts on offspring performance. Such effects are likely to be of ecological and evolutionary importance in animals with extended parental care, such as birds, mammals and some insects. Here, we studied the effects of exposure to microbial competition during early development on subsequent reproductive success in the burying beetle Nicrophorus vespilloides, an insect with elaborate parental care. We found that exposure to high levels of microbial competition both during a female’s larval development and during her subsequent reproduction resulted in females rearing smaller broods than those exposed to lower levels of microbial competition. To determine whether these differences arose before or after offspring hatching, a cross-fostering experiment was conducted. Our results demonstrate that the impact of larval competition with microbes for resources extends into adult life and can negatively affect subsequent generations via impacts on the quality of parental care provided after hatching. However, we also find evidence for some positive effects of previous microbial exposure on pre-hatch investment, suggesting that the long-term results of competition with microbes may include altering the balance of parental investment between pre-hatch and post-hatch care.